towards a portuguese participation in the ess project, 29 th jan. 2010, lisbon carlos martins –...

Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE

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Carlos A. Martins

Instituto Superior Técnico (IST) – Technical University of Lisbon

Centre for Innovation in Electrical and Energy Engineering (CIEEE)

(formerly a section leader at CERN in the power converters group)


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1.- Introduction on Power Supplies for particle accelerators- Classifications;

2.- Main issues to be considered in the design- Load Regime (topology), Precision, EMC compliance, Remote controls, Safety,

Reliability/maintenability;

3.- Examples of magnet power supplies (CERN case study)- “Of the shelf”;- Custom made;

4.- Solid state klystron modulators for proton Linac´s

5.- Potential contributions from CIEEE / IST

6.- Conclusions


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1.- Power Supplies for magnets

- beam bending magnets;- beam correction magnets (steerers, quadrupoles, solenoids, sextupoles, etc.);- beam kicking magnets (septa, kickers);- “special purpose” (gamma transition, beam scope meters, etc.);

2.- Power Supplies for RF tubes- Tetrodes for RF generators in particle sources;- Klystron / IOT modulators for accelerating structures;

Classification based on the load type


Classification based on load regimeRegime mode Energy

efficiency

Cost / Volume

Voltage (V), Current (I) waveforms

Physics Machine

1.- DC mode• 1-quadrant (V+ ; I+); Low High

DC SynchrotronsOrSuperconducting machines

2.- Function tracking mode• 1-quadrant (V+ ; I+);• 2-quadrants (V+/- ; I+);• 4-quadrants (V+/- ; I+/-)

MediumMediu

m

Normal conductingFast Cycling SynchrotronsOr Transfer Line Bending magnets

3.- Pulsed mode• 2-quadrants (V+/- ; I+)

Highest Lowest

Normal conducting LINAC’s and Transfer Lines

t(s)0

V, I

t(s)

0

V, I

t(ms)

0

V, I


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1. Load regime (power)• selection of topology (DC, function tracking, pulsed);• nº of quadrants;• Cabling and AC feeders;• Cooling (air natural or forced; water);

2. Precision• Stability (over one year ?, one day ?, half an hour ?);• Reproducibility (pulse to pulse);• “Precision budget” should be established together with beam dynamics

specialists;• Impact mostly from the choice of DCCT’s (magnets supplies) or HV voltage

dividers (RF tube supplies);• These complex sensor devices are manufactured by very few companies (i.e.

Danfysik, Hitec, North Star,...);

3. EMC compliance• All power supplies should be compliant with international standards in terms of

EMC emissions and immunity. Specific testing campaigns shall be planned and executed during prototyping and production acceptance;

• The guarantee that all systems (power supplies, instrumentation electronics, ...) will perform correctly once integrated together in the machine


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4. Remote Control System• Selection of the fieldbus (WorldFIP?, ScienceFIP?, Ethernet?, WhiteRabbit?, ...);• Interface with the low-level controller part in the power supplies;• Physical layout of the controller (single board?, cassette?, chassis?,...);• Should be UNIQUE to all power supplies in the physics complex;• Online monitoring, diagnosis and “post mortem” facilities;

5. Reliability and maintainability• MTBF – Mean Time Between Failures (should be ~ 10 years, individually; if total

power supplies = 1000 -> Total MTBF = 4 days);• Lifetime should be ~20 years by design (ageing of components like capacitors,

obsolescence, thermal cycling of semiconductors must be taken into account);

• MTTR – Mean Time to Repair (should be ~1 hour);• Spare parts and spare power supplies policy (shall be foreseen from the very

early stage of the project and included in call for tenders; inventory data-base created and updated);

6. Safety• Fire risks (special cables?);• Access for operation (Grounding equipment, capacitor discharge systems,...);• Presence of oil in HV equipments (leakage retainers, fire prevention systems, ...);


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Danfysik

Delta Elektronika

Heinzinger

FUG

Technix

• High Voltage DC;• Capacitor Chargers

• High Voltage DC;• Medium Voltage DC;• Capacitor Chargers

• Low voltage DC

• Low voltage DC • Low voltage DC;• High Voltage DC;• Capacitor Chargers


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Developed for

CERN PS Consolidation program

PS Gamma Transition(500Apk, +/-6kVpk)

PS Pole Face Windings(+/-250A, +/-1.2kV)

PS Pole Face Windings(+/-1600A, +/-600V)

Function tracking type


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CERN Linac2, PS Booster & PS Consolidation programs

Also foreseen for Linac4

19”,3U

7 ms

20A

Linac2 & PSB TLSteerers

(Pulsed:20Apk, 600Vpk,

5ms/5 Hz)

Pulsed type

voltage

current

1 ms

300A

500V

Power crate 19”, 6U

Electronics crate 19”, 3U

Linac2 & Linac3Quads

(Pulsed: 300Apk, 1kVpk,

1ms/5 Hz)

Septa current

PS injection / extraction Septa

(Pulsed:20kApk, 300Vpk,

0.6ms/1 Hz)


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Typical RequirementsKlystron power supply

- Pulse width: ~2 ms- Flat-top duration ~1.5 ms- Precision at flat-top: < 1%- HF ripple at flat-top: < 0.1%- Repetition rate: 2..50 Hz- Nominal voltage: ~120 kV- Nominal current: ~20..100 A- Nominal power (peak): ~10 MW- Rise/fall times (99% / 1%): ~10% of Pulse width- Maximum energy in case of arc: < 20 J

Pulse width

Rise time Fall time

timeFlat-top

V

Shape of High Voltage Pulses

Collector(GND)

Cathode(-)

~ hundred kV+-


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Also foreseen for:

- Project X @ Fermilab;- XFEL @ Desy;

•The FERMILAB / DESY type modulator

(Without pulse transformer)

Simplified schematic, with pulse transformer

120 kV, 140A, 2.3ms, 10 Hz


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•CERN Prototype (3-MeV Test Stand & Linac4)

Simplified schematics

PULSETRANSFORMER

(OIL TANK)

Main solid stateswitches

A1

C

KF

1:10

Ca

pa

cit

or

ba

nk

ch

arg

er

po

we

r c

on

ve

rte

r, P

S1

Anode powerconverter, PS3

A - Anode;C - Collector;K - Cathode;F - Filament

Filament powerconverter, PS4

Vout

Droop compensation powerconverter or “bouncer”, PS2

0.1mF

Capacitordischarge

system

VPS1

VPS2

12 kV max-1

20

kV

ma

x

KLYSTRON(OIL TANK)

DC

Hign FrequencyISOLATION

TRANSFORMER

DC

K1

PS1, PS3, PS4 - CommercialPS2 - CERN made

120 kV High voltage cables

120 kV High voltage connectors

DIODERECTIFIER

A

DRIVER DRIVER

100 kV, 20A, 0.8ms, 2 Hz


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• SLAC PrototypeAlso a candidate for:

- ILC;115 kV, 135A, 1.5 ms, 5 Hz


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• Oak Ridge (SNS) modulators 140 kV, 70A, 1.6ms, 60 Hz(9.8 MWpk, 940 kWav)

AC/DC input converter not shown


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• J-PARC modulators


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1. Carry on Studies for the Technical Design Report and Work-Package Description• Define main parameters, types and quantities for each application (in close collaboration with

magnets team (magnet power supplies), RF team (klystron modulators) and beam dynamics team;• Propose topologies/references taking into account the market availability;• Define remote control system (in close collaboration with controls people);• Estimate costs, volumes, auxiliary requirements (water cooling, AC electrical feeders, AC and DC

cables);• Planning;

2. Studies on Klystron Modulator Topologies• Evaluate in detail the existing topologies;• Propose the most suited topology for ESS (High power, High repetition ratio);• Study in detail the adopted topology by simulation and small scale prototyping (~same voltage, ~10%

of rated power);• Synergy with CERN possible;Or alternatively (consulting):• Participate in writing-up of technical specifications and test protocols;• Evaluate commercial offers; follow-up of contracting milestones; participate in the testing campaign;

3. Realization of prototypes for “custom made” power supplies

4. Write-up technical specifications, test protocols. Follow-up of construction and validation

On Power Supplies and Klystron Modulators:


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1. Power Supplies and Klystron Modulators are key technologies in accelerators• “Klystron modulators are probably the second most challenging sub-systems in high duty-cycle

Linac’s, just after accelerating structures…” – Maurizio Vretenar, CERN Linac4 Project Leader;• Very few European and Worldwide companies are able to develop and produce such specific

equipment (particularly for klystron modulators)

2. “Of the Shelf” versus “customized” solutions should be carefully evaluated• At least 2 solid companies (preferably 3) shall be able to provide the same or equivalent “Of the

shelf” product (double source), to avoid risks of bankruptcy, monopoles in the long term future;• The project team shall have a “word to say” on the selection of the topology (technology); Do not

delegate entirely this responsibility to companies;• Careful about functional specifications (technical specifications would be preferable…): - Too

much freedom given to companies on “turn-key” solutions may put the whole project dependent on a single company in terms of delays, performance, long term reliability and maintainability;

3. Close follow-up of companies’ technical activities is essential• Single contracts (not a long term based commercial exchange);• Companies main objective: Profit (which is perfectly fair and honourable);• Project main objectives: Systems ready on time according to specifications; Reliable and

maintainable in long term (20 years);• Be sure to get all documentation, knowledge and relevant information about the equipment;• Before placing a contract:- cross-check all parameters and technical details with the other partners of

the project;• Be sure the specifications are clear and cover all pertinent technical details. Companies will

challenge you on this capability…

towards a portuguese participation in the ess project, 29 th jan. 2010, lisbon carlos martins –...

Documents

ess project

systems power supplies

total power supplies

portuguese participation

quadrants v

cieee ist

power crate

spare power supplies