power supply system for negative ion source at ipr - iopscience
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Journal of Physics Conference Series
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Power supply system for negative ion source atIPRTo cite this article Agrajit Gahlaut et al 2010 J Phys Conf Ser 208 012030
View the article online for updates and enhancements
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Power supply system for Negative Ion Source at IPR
Agrajit Gahlaut Jashwant Sonara K G Parmar Jignesh Soni M Bandyopadhyay Mahendrajit Singh Gourab Bansal Kaushal Pandya and Arun Chakraborty
Institute for Plasma Research Gandhinagar Gujarat ndash 382428 India
agrajitiprresin
Abstract The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly ndash RF based where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ~5 x 1012 cm-3 from which ~ 10 A of negative ion beam shall be produced and accelerated to 35 kV through an electrostatic ion accelerator The experimental system is modelled similar to the RF based negative ion source BATMAN presently operating at IPP Garching Germany The mechanical system for Negative Ion Source Assembly is close to the IPP source remaining systems are designed and procured principally from indigenous sources keeping the IPP configuration as a base line High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup The HV power supplies for extraction and acceleration are rated for high voltage (~15 to 35kV) and high current (~ 15 to 35A) Other attributes are fast rate of voltage rise (lt 5ms) good regulation (lt plusmn1) low ripple (lt plusmn2) isolation (~50kV) low energy content (lt 10J) and fast cut-off (lt 100micros) The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids have attributes of low ripple high stability fast and precise regulation programmability and remote operation These power supplies are also equipped with over-voltage over-current and current limit (CC Mode) protections Fault diagnostics to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme To restrict the fault energy deposited on the ion source specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy Moreover the monitoring status and control signals from these power supplies are required to be electrically (~ 50kV) isolated from the system The paper shall present the design basis topology selection manufacturing testing commissioning integration and control strategy of these HVPS A complete power interconnection scheme which includes all protective devices and measuring devices low amp high voltage power supplies monitoring and control signals etc shall also be discussed The paper also discusses the protocols involved in grounding and shielding particularly in operating the system in RF environment
1 Introduction RF based negative ion facility is currently under development in IPR [1] For the operation of such a facility various power supplies are required as shown in lsquoFigure 1rsquo Since the negative ion source assembly at IPR is similar to the ion source at IPP the majority of the specifications are derived from this already existing system
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
ccopy 2010 IOP Publishing Ltd 1
Figure 1 Block diagram of power supply system for negative ion source at IPR
Plasma is produced by an oscillator RF generator which utilizes a separate power supply to drive the oscillator The power supply for the RF generator is a bought out item and is not discussed in this paper Regulated High Voltage Power Supplies (RHVPS) with low energy content fast rise time and various other critical parameters are required for the process of Extraction and Acceleration which are discussed later in this paper These Power supplies should be remotely operated and equipped with all necessary protective devices for the safety of the power supply as well as the source A passive protection scheme (Snubber) will also be incorporated which will provide protection against the grid breakdowns In addition to this various other isolated low to medium power heating and bias power supplies are required for beam production and control This includes Filament Bias Filament Heating Grid Bias and Grid Heating power supplies The Filament circuit assists in plasma generation Plasma Grid and Bias circuit is used for electron suppression The input power to these power supplies will be fed through MCB based sub-distribution panels housed with necessary electrical protection devices A 50kV DC isolation transformer will be used to feed the AC power to the power supplies which are floating at the source potential To avoid grounding problems like the ground loops and the noise pickups a star point based grounding scheme has been designed A complete power interconnection and integration scheme is designed showing all the power supplies protecting amp measuring devices and all the control and monitoring signals
2 Ion source High Voltage Power Supplies (HVPS) The high voltage system for the negative ion source consists of the following two power supplies
bull Extraction HVPS for extracting the negative ion bull Acceleration HVPS for accelerating the beam
The common characteristics of these power supplies are isolation from ground regulation low ripple amplitude and dynamic response of few milli seconds Moreover the HVPS power supplies (accelerator and extraction) should trip within 100micros in case of grid breakdown which is a common
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
2
phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively
Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Three major power supply topologies are explored to generate the regulated high voltage DC This
include
bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)
The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed
by a step up transformer and controlled rectifier
Figure 2 AC thyristorized power controller based topology with series switch
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
3
The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules
Figure 3 PWMPSM based RHVPS with multi-secondary transformer
Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The
output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system
Figure 4 Rectifier inverter based topology with High frequency transformer
Technical comparison of the all the three technologies is tabulated in table 3
Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices
Yes Yes No
Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR
Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
4
Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices
lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation
Figure 5 Integration and measurement scheme for HVPS
High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is
rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros
Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
5
Figure 6 The cut-off and turn-on sequence of HVPS during breakdown
A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo
Figure 7 Typical Scheme for Grid Breakdowns and over-current detection
The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and
compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)
Figure 8 (a) Startup procedure of HVPS
Figure 8 (b) Operational procedure of HVPS
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
6
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
Power supply system for Negative Ion Source at IPR
Agrajit Gahlaut Jashwant Sonara K G Parmar Jignesh Soni M Bandyopadhyay Mahendrajit Singh Gourab Bansal Kaushal Pandya and Arun Chakraborty
Institute for Plasma Research Gandhinagar Gujarat ndash 382428 India
agrajitiprresin
Abstract The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly ndash RF based where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ~5 x 1012 cm-3 from which ~ 10 A of negative ion beam shall be produced and accelerated to 35 kV through an electrostatic ion accelerator The experimental system is modelled similar to the RF based negative ion source BATMAN presently operating at IPP Garching Germany The mechanical system for Negative Ion Source Assembly is close to the IPP source remaining systems are designed and procured principally from indigenous sources keeping the IPP configuration as a base line High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup The HV power supplies for extraction and acceleration are rated for high voltage (~15 to 35kV) and high current (~ 15 to 35A) Other attributes are fast rate of voltage rise (lt 5ms) good regulation (lt plusmn1) low ripple (lt plusmn2) isolation (~50kV) low energy content (lt 10J) and fast cut-off (lt 100micros) The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids have attributes of low ripple high stability fast and precise regulation programmability and remote operation These power supplies are also equipped with over-voltage over-current and current limit (CC Mode) protections Fault diagnostics to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme To restrict the fault energy deposited on the ion source specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy Moreover the monitoring status and control signals from these power supplies are required to be electrically (~ 50kV) isolated from the system The paper shall present the design basis topology selection manufacturing testing commissioning integration and control strategy of these HVPS A complete power interconnection scheme which includes all protective devices and measuring devices low amp high voltage power supplies monitoring and control signals etc shall also be discussed The paper also discusses the protocols involved in grounding and shielding particularly in operating the system in RF environment
1 Introduction RF based negative ion facility is currently under development in IPR [1] For the operation of such a facility various power supplies are required as shown in lsquoFigure 1rsquo Since the negative ion source assembly at IPR is similar to the ion source at IPP the majority of the specifications are derived from this already existing system
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
ccopy 2010 IOP Publishing Ltd 1
Figure 1 Block diagram of power supply system for negative ion source at IPR
Plasma is produced by an oscillator RF generator which utilizes a separate power supply to drive the oscillator The power supply for the RF generator is a bought out item and is not discussed in this paper Regulated High Voltage Power Supplies (RHVPS) with low energy content fast rise time and various other critical parameters are required for the process of Extraction and Acceleration which are discussed later in this paper These Power supplies should be remotely operated and equipped with all necessary protective devices for the safety of the power supply as well as the source A passive protection scheme (Snubber) will also be incorporated which will provide protection against the grid breakdowns In addition to this various other isolated low to medium power heating and bias power supplies are required for beam production and control This includes Filament Bias Filament Heating Grid Bias and Grid Heating power supplies The Filament circuit assists in plasma generation Plasma Grid and Bias circuit is used for electron suppression The input power to these power supplies will be fed through MCB based sub-distribution panels housed with necessary electrical protection devices A 50kV DC isolation transformer will be used to feed the AC power to the power supplies which are floating at the source potential To avoid grounding problems like the ground loops and the noise pickups a star point based grounding scheme has been designed A complete power interconnection and integration scheme is designed showing all the power supplies protecting amp measuring devices and all the control and monitoring signals
2 Ion source High Voltage Power Supplies (HVPS) The high voltage system for the negative ion source consists of the following two power supplies
bull Extraction HVPS for extracting the negative ion bull Acceleration HVPS for accelerating the beam
The common characteristics of these power supplies are isolation from ground regulation low ripple amplitude and dynamic response of few milli seconds Moreover the HVPS power supplies (accelerator and extraction) should trip within 100micros in case of grid breakdown which is a common
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
2
phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively
Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Three major power supply topologies are explored to generate the regulated high voltage DC This
include
bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)
The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed
by a step up transformer and controlled rectifier
Figure 2 AC thyristorized power controller based topology with series switch
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
3
The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules
Figure 3 PWMPSM based RHVPS with multi-secondary transformer
Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The
output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system
Figure 4 Rectifier inverter based topology with High frequency transformer
Technical comparison of the all the three technologies is tabulated in table 3
Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices
Yes Yes No
Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR
Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
4
Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices
lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation
Figure 5 Integration and measurement scheme for HVPS
High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is
rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros
Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
5
Figure 6 The cut-off and turn-on sequence of HVPS during breakdown
A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo
Figure 7 Typical Scheme for Grid Breakdowns and over-current detection
The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and
compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)
Figure 8 (a) Startup procedure of HVPS
Figure 8 (b) Operational procedure of HVPS
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
6
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
Figure 1 Block diagram of power supply system for negative ion source at IPR
Plasma is produced by an oscillator RF generator which utilizes a separate power supply to drive the oscillator The power supply for the RF generator is a bought out item and is not discussed in this paper Regulated High Voltage Power Supplies (RHVPS) with low energy content fast rise time and various other critical parameters are required for the process of Extraction and Acceleration which are discussed later in this paper These Power supplies should be remotely operated and equipped with all necessary protective devices for the safety of the power supply as well as the source A passive protection scheme (Snubber) will also be incorporated which will provide protection against the grid breakdowns In addition to this various other isolated low to medium power heating and bias power supplies are required for beam production and control This includes Filament Bias Filament Heating Grid Bias and Grid Heating power supplies The Filament circuit assists in plasma generation Plasma Grid and Bias circuit is used for electron suppression The input power to these power supplies will be fed through MCB based sub-distribution panels housed with necessary electrical protection devices A 50kV DC isolation transformer will be used to feed the AC power to the power supplies which are floating at the source potential To avoid grounding problems like the ground loops and the noise pickups a star point based grounding scheme has been designed A complete power interconnection and integration scheme is designed showing all the power supplies protecting amp measuring devices and all the control and monitoring signals
2 Ion source High Voltage Power Supplies (HVPS) The high voltage system for the negative ion source consists of the following two power supplies
bull Extraction HVPS for extracting the negative ion bull Acceleration HVPS for accelerating the beam
The common characteristics of these power supplies are isolation from ground regulation low ripple amplitude and dynamic response of few milli seconds Moreover the HVPS power supplies (accelerator and extraction) should trip within 100micros in case of grid breakdown which is a common
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
2
phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively
Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Three major power supply topologies are explored to generate the regulated high voltage DC This
include
bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)
The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed
by a step up transformer and controlled rectifier
Figure 2 AC thyristorized power controller based topology with series switch
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
3
The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules
Figure 3 PWMPSM based RHVPS with multi-secondary transformer
Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The
output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system
Figure 4 Rectifier inverter based topology with High frequency transformer
Technical comparison of the all the three technologies is tabulated in table 3
Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices
Yes Yes No
Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR
Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
4
Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices
lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation
Figure 5 Integration and measurement scheme for HVPS
High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is
rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros
Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
5
Figure 6 The cut-off and turn-on sequence of HVPS during breakdown
A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo
Figure 7 Typical Scheme for Grid Breakdowns and over-current detection
The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and
compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)
Figure 8 (a) Startup procedure of HVPS
Figure 8 (b) Operational procedure of HVPS
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
6
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively
Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt
Three major power supply topologies are explored to generate the regulated high voltage DC This
include
bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)
The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed
by a step up transformer and controlled rectifier
Figure 2 AC thyristorized power controller based topology with series switch
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
3
The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules
Figure 3 PWMPSM based RHVPS with multi-secondary transformer
Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The
output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system
Figure 4 Rectifier inverter based topology with High frequency transformer
Technical comparison of the all the three technologies is tabulated in table 3
Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices
Yes Yes No
Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR
Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
4
Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices
lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation
Figure 5 Integration and measurement scheme for HVPS
High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is
rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros
Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
5
Figure 6 The cut-off and turn-on sequence of HVPS during breakdown
A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo
Figure 7 Typical Scheme for Grid Breakdowns and over-current detection
The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and
compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)
Figure 8 (a) Startup procedure of HVPS
Figure 8 (b) Operational procedure of HVPS
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
6
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules
Figure 3 PWMPSM based RHVPS with multi-secondary transformer
Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The
output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system
Figure 4 Rectifier inverter based topology with High frequency transformer
Technical comparison of the all the three technologies is tabulated in table 3
Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices
Yes Yes No
Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR
Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
4
Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices
lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation
Figure 5 Integration and measurement scheme for HVPS
High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is
rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros
Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
5
Figure 6 The cut-off and turn-on sequence of HVPS during breakdown
A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo
Figure 7 Typical Scheme for Grid Breakdowns and over-current detection
The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and
compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)
Figure 8 (a) Startup procedure of HVPS
Figure 8 (b) Operational procedure of HVPS
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
6
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices
lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation
Figure 5 Integration and measurement scheme for HVPS
High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is
rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros
Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
5
Figure 6 The cut-off and turn-on sequence of HVPS during breakdown
A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo
Figure 7 Typical Scheme for Grid Breakdowns and over-current detection
The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and
compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)
Figure 8 (a) Startup procedure of HVPS
Figure 8 (b) Operational procedure of HVPS
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
6
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
Figure 6 The cut-off and turn-on sequence of HVPS during breakdown
A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo
Figure 7 Typical Scheme for Grid Breakdowns and over-current detection
The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and
compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)
Figure 8 (a) Startup procedure of HVPS
Figure 8 (b) Operational procedure of HVPS
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
6
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure
31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies
Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current
Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON
32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm
Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
7
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
Figure 9 Startup and Operation algorithm of Grid heating power supply
Figure 10 Startup and Operation algorithm of Grid bias power supply
Figure 11 Startup and Operation algorithm Cs oven power supply
33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence
Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I
34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply
4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
8
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative
Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)
Figure 12 Power supply output connections
5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load
Figure 13 Typical passive protection scheme (snubber) for grid breakdowns
As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material
surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel
The snubber parameters can be calculated form the following mathematical relation
CRL timestimes= 24 (1)
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
9
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown
6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR
Figure 14 Typical grounding scheme for the negative ion system at IPR
The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
10
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point
7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR
Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)
8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
11
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
16V 10A DC POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-16VDC 10A+
-
230v50Hz
~
~
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
90VDC 500mA+
-
230v50Hz
~
~
+
-
5V
RETURN
5V24V
0V
DCCT 0-5v 0-1A
+ - + -
+ - + -
+ - + -
+ - + -
+ - + -
9V 9V
9V 9V
9V 9V
9V 9V
9V 9V
FILAMENT BIAS POWER SUPPLY
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
30V 66A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFF
0V
0-30VDC 66A+
-
230v50Hz
~
~
ACC - S218 1A
+
-
4V
RETURN
4V+15V0V
DCCT 0-4v 0-100ALEM HAL 100-S
15v DCPS+
-
15v
0v
~
~
230v50Hz
-15V
15v
+-
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
RF FAST IL CARD
GRID BIAS POWER SUPPLY
FILAMENT HEATER POWER SUPPLY
TTL LOW - OSC OFF HIGH - OSC ON
TX
TX
RX
RX
REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)
OPTION -B FOR ON (WITH STATUS)
24v DCPS+
-
24v
0v
~
~
230v50Hz
P
N
100k1k
LED
65V 10A DC POWER SUPPLY
GRID BIAS POWER SUPPLY
~
~
+
-
230v50Hz
V
V-SET
I
I-SET
AUXCONTACT
16A POWER CONTACTOR
K
24V
SNUBBERPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
COM
STATUS
STATUS = 24V PS ONSTATUS = 0V PS OFF
0V
0-65VDC 10A+
-
230v50Hz
~
~
V-MONCOM
I-MONCOM
V-SETCOM
I-SETCOM
GRID HEATING POWER SUPPLY
TX
TX
RX
RX
MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)
P N
P N
PLASMA GRID
EXTRACTION GRID
EARTH GRID
TX
P N
P N
REGULATED HVPS
(EXTRACTION)
15kV 35A
REGULATED HVPS
(ACCELERATOR)
35kV 15A
+
-
+
-
12v 60kv5000X DIVIDER
35kV = 7V
12v 60kv5000X DIVIDER
35kV = 7V
I-ion
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA15A = 15mA
15mA x 30E = 045v
I-erd
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
TX
P N
200A 200mA
5A x 10 TURNS = 50A --gt 50mA
50mA x 30E = 15v
10 TURNS
I-elec
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA20A = 20mA
20mA x 30E = 06v
12v 60kv
5000X DIVIDER
50kV = 10V
12v 60kv
5000X DIVIDER
50kV = 10V
I-drain
30E
15v DCPS+
-
15v
0v
~
~
230v50Hz
15v
+-
200A 200mA
35A = 35mA
35mA x 30E = 105v
DEDICATED GROUND
UTILITY GROUND
AUTO-GND SWITCH MANUAL-GND SWITCH
240240
PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV
DC ISOLATION XMER
[SEC COMPENSATEDFOR REGULATION]
+Vc -VcI
+Vc -VcI
+Vc -VcI
+Vc -VcI
A
B
A
BA
B
A
B
A
B
A B
A
B
A
B
A
B
SNUBBER
SNUBBER
FILAMENT
DCCT
DCCT
DCCT
DCCT
SHIELD
1 Ph 230V 50Hz
HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION
14-08-2008 REV-1
STAR GROUND
60kV DC TRIAX
60kV DC TRIAX
60kV DC TRIAX
4-TURNS --gt 18v
PULSE CT - DRAIN
P-DRAIN-1
P-DRAIN-2
PULSE CT - ELEC
P-ELEC-1
P-ELEC-2
P-DRAIN-1P-DRAIN-2
I-DRAIN-1I-DRAIN-2
I-DRAIN-1I-DRAIN-2
OR
BUFFER
BUFFER
Iref
DRAIN-BREAK-TTL-DAC
PS-TRIP-TTL
DRAIN-OC-TTL-DAC
DRAIN-I-MONITOR-DAC
I-ELEC-1I-ELEC-2
V-HV-IN V-HV-OUT
V-ACC-IN V-ACC-OUT
V-HV-IN-1V-HV-IN-2
V-HV-OUT-1V-HV-OUT-2
V-ACC-IN-1V-ACC-IN-2
V-ACC-OUT-1V-ACC-OUT-2
I-ERD-MONITORTO DAC
P-ELEC-1P-ELEC-2
BUFFER
BUFFER
Iref
ELEC-BREAK-TTL-DAC
ELEC-OC-TTL-DAC
ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2
I-ION-1I-ION-2
PULSE CT - ION
P-ION-1
P-ION-2
P-ION-1P-ION-2
BUFFER
BUFFER
Iref
ION-BREAK-TTL-DAC
ION-OC-TTL-DAC
ION-I-MONITOR-DACI-ION-1I-ION-2
BUFFER
Vref
V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2
V-HV-IN-OV-TTL-DAC
BUFFER
Vref
V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2
V-HV-OUT-OV-TTL-DAC
BUFFER
Vref
V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2
V-ACC-IN-OV-TTL-DAC
BUFFER
Vref
V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2
V-ACC-OUT-OV-TTL-DAC
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1ASi4 25A
R4-2
R4-1
R2-1
1
CT5
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
Uf
230AC
R1-5R1-4
R3-5R3-4
R4-5R4-4
R5-5R5-4
TE1 TE2 TE3 TE4 TE5
1 2 3 4 5 6 7 8 9 1011 12
HEATING-3Cartridge-3
31 2 4 5 6 7 8 9 1011 12
31 2 4 5 6 7 8 9 1011 12
HEATING-2Cartridge-2
1 2 3 4 5 6 7 8 9 1011 12
2 3 4 5 6 7 8 9 10 11 12
Cartridge-1HEATING-1
R2-4R2-5
CT1
CT5
230AC
230AC
230AC
230AC
R1
R2
R3
R4
R5
R=Temperature Controler
West 66OO
WTO7O5OOdegc (Batman)WO23500degc (L6)
Part modified
LWL
R1-910
SiR 2A
EinNETWORK
20mA60V
033uF250V
Lemo A
Network module
Si6 2x 4ANETWORKEin
60V
033uF250V
20mA40V
40V
Cartridge-2HEATING-2HEATING-1
Cartridge-1PipeHEATING-5
BodyHEATING-4 HEATING-3
Cartridge-3
Si1 25A Si2 25A Si3 25A
R3-2
R3-1
R2-2
R1-1
R1-2
R5-2
R5-1
Si5 1A
R4-2
R4-1
R2-1
1
V
V
V
HEATING-4Body
HEATING-5Pipe
K1
CT4
CT1 CT2 CT3
CT2
CT3
CT4
230v50Hz
~A
B ~
Cs OVEN POWER SUPPLY
COIL 3COIL 2COIL 1
COIL 4COIL 5
GRIDHEATING
MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT
Cs OVEN
V-MON-GB
I-MON-GB
V-SET-GB
V-SET-GB
24v DCPS+
-
24v
0v
~
~
230v50Hz 100k
1k
LED
AUXCONTACT
COM
STATUS
STATUS = 24V PS ON
STATUS = 0V PS OFFPFC
TTL
~ ~
TTL TO PFC
230v50Hz
PS ON0V - OFF24V - ON
A B
A
B
COIL 1COIL 2COIL 3COIL 4COIL 5
FROM Cs OVENPOWER SUPPLY
V-MON-GH
I-MON-GH
V-SET-GH
V-SET-GH
(TX) 5-CHANNEL (OVEN TEMPERATURE)
Figure 16 Detailed interconnection scheme
9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system
Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP
10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific
instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911
23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030
12