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1

POWER ELECTRONICSAND SIMULATION LAB

3rd YEAR-II SEMESTER

NAME OF THE STUDENT :

REGISTERNUMBER :

YEAR/ SEMESTER :

STAFF INCHARGE : Mr. G.SRIDHAR BABU Assoc.Prof/EEE

2

General Instructions to students for EEE Lab courses

Be punctual to the lab class.

Attend the laboratory classes wearing the prescribed uniform and shoes.

Avoid wearing any metallic rings, straps or bangles as they are likely to prove dangerous at times.

Girls should put their plait inside their overcoat

Boys students should tuck in their uniform to avoid the loose cloth getting into contact with rotating machines.

Acquire a good knowledge of the surrounding of your worktable. Know where the various live points are situated in your table.

In case of any unwanted things happening, immediately switch off the mains in the worktable.

This must be done when there is a power break during the experiment being carried out.

Before entering into the lab class, you must be well prepared for the experiment that you are going to do on that day.

Get the circuit diagram approved.

Prepare the list of equipments and components required for the experiment and get the indent approved.

Make connections as per the approved circuit diagram and get the same verified. After getting the approval only supply must be switched on.

Get the reading verified. Then inform the technician so that supply to the worktable can be switched off.

You must get the observation note corrected within two days from the date of completion of experiment. Write the answer for all the discussion questions in the observation note. If not, marks for concerned observation will be proportionately reduced.

Submit the record note book for the experiment completed in the next class.

If you miss any practical class due to unavoidable reasons, intimate the staff in charge and do the missed experiment in the repetition class.

Such of those students who fail to put in a minimum of 75% attendance in the laboratory class will run the risk of not being allowed for the University Practical Examination.

3

LIST OF EXPERIMENTS

Any eight of the experiments in power electronics lab

1. Study of characteristics of SCR, MOSFET, & IGBT.

2. Gate firing circuit for SCR’s.

3. Single phase AC voltage controller with R AND RL loads.

4. Single phase fully controlled bridge converter with R load and RL loads

5. Forced commutation circuits (Class A, Class B, Class C, Class D & Class E).

6. DC Jones chopper with R and RL loads.

7. Single phase parallel inverter with R and RL loads.

8. Single phase cycloconverter with R and RL loads.

9. Single phase half controlled converter with R loads.

10. Three phase half controlled bridge converter with R loads.

11. Single phase series inverter with R and RL loads.

12. Single phase bridge converter with R and Rl loads.

13. Single phase dual converter with RL loads.

14. Operation of MOSFET based chopper.

Any two simulation experiments with PSPICE/PSIM

15. PSPICE simulation of single phase full converter using RLE loads and single phase

AC voltage controller using RLE loads.

16. PSPICE simulation of resonant pulse commutation circuit and buck chopper.

17. PSPICE simulation of single phase inverter with PWM control.

4

LIST OF CYCLE-I

1. Single phase AC voltage controller with R AND RL loads.

2. DC Jones chopper with R and RL loads.

3. Single phase parallel inverter with R and RL loads.

4. Single phase half controlled converter with R loads.

5. PSPICE simulation of single phase full converter using RLE loads and single phase

AC voltage controller using RLE loads.

LIST OF CYCLE-II

6. Gate firing circuit for SCR’s.

7. Single phase fully controlled bridge converter with R load and RL loads.

8. Forced commutation circuits (Class A, Class B, Class C, Class D & Class E).

9. Single phase cycloconverter with R and RL loads

10. PSPICE simulation of single phase inverter with PWM control.

.

5

TABLE OF CONTENTS

Sl.No Experiment Name Experiment Date

Submission date

Marks Signature

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

SUBJECT INCHARGE INTERNAL MARK---------

6

Exp. No.:1 Date:

SINGLE PHASE AC VOLTAGE CONTROLLER WITH R AND RL LOADS

1.1 OBJECTIVE:

To study the module and waveforms of a 1-Φ AC voltage controller with R and RL loads.

1.2 RESOURCES:

S. No. Name of the Apparatus Range Type Quantity

11 AC voltage regulator

power module - - 1

2 Loading Rheostat 50, 2A - 1

3 Loading Inductor 150mH, 2A - 1

4 CRO & probe 20MHz Dual 1

5 Connecting wires - As required

1.3 SPECIFICATIONS:

1. Input 1, 230V, 50Hz AC Supply

2. Load R and RL.

3. Thyristors 12A, 600V, type 25 RIA 120.

4. TRIACs 10A, 600V, BT136.

5. MCB Two pole 230V/16A.

6. Fuses 16A HRC.

7. Step down transformer 230V/24V-0-24V, 2A.

1.4 PRECAUTIONS:

1. Make sure all the connecting links are tightly fixed.

2. Ensure all the controlling knobs in fully counterclockwise position before starting experiment.

3. Handle everything with care.

4. Make sure the firing pulses are proper before connecting to the power circuit.

5. Make sure to connect firing pulses from the firing circuit to their corresponding SCRs/TRIAC

in the power circuit.

7

1.5 MODEL GRAPH:

Input Waveform

Output Waveform Across R and RL- Load =00

0 π 2π 3π 4πt (ms)

Vi (v)

0

VL (v)

t (ms)

0

VL (v)

t (ms)

Output Waveform Across R- Load =900

0

VL (v)

t (ms)

Output Waveform Across RL- Load =900

8

1.6 PROCEDURE:

1. Switch ON the mains supply to the firing circuit. Observe the trigger outputs by varying firing

angle potentiometer and by operating On/OFF and SCR/TRIAC selector switch. Make sure the

firing pulses are proper before connecting to the power circuit.

2. Make the connections as per the circuit diagram.

3. Connect firing pulses from the firing circuit to the corresponding SCRs/TRIAC in the power

circuit.

4. Switch ON the step down transformer supply (MCB) and now switch ON the trigger pulses by

operating ON/OFF switch in the firing circuit.

5. Observe the output voltage waveform across load using oscilloscope.

6. Note down the input voltage, firing angle and output voltage readings in the TABULAR

FORMS.

7. Draw the waveforms in the graph at 0, 45, 90, 135 and 180 Deg. firing angles.

FORMULAE USED:

Output voltage, V0 = Vs

2

2sin1

9

0-250mH, 2A

P

N

1, 230V, 50Hz, AC

230V

0V

0V

24V

G

TRIACBT136

R

L

LOAD50,2A

SINGLE PHASE AC VOLTAGE CONTROLLER WITH RL LOAD USING TRIAC

MT1

G MT2FIRING CIRCUIT

24V

MT2

P

N

1, 230V, 50Hz, AC

230V

0V

0V

24V

K1

K2

A1

A2

G1

T1

T2

2TYN616

R

L

LOAD50,2A

SINGLE PHASE AC VOLTAGE CONTROLLER WITH RL LOAD USING SCRS

G2

K1 G1 K2 G2

24V

10

1.7 TABULAR FORMS: 1. for R load

S.No. Input voltage (V)Firing angle

()

Output voltage

(V)

Theoretical

output

voltage (V)

1.7 TABULAR FORMS: 2. RL load:

S.No. Input voltage (V)Firing angle

()

Output voltage

(V)

Theoretical

output

voltage (V)

P

N

1, 230V, 50Hz, AC

230V

0V

0V

24V

K1

K2

A1

A2

G1

T1

T2

2TYN616

RLOAD

50,2A

SINGLE PHASE AC VOLTAGE CONTROLLER WITH R LOAD USING SCRS

G2

K1 G1 K2 G2

24V

11

1.8 MODEL CALCULATIONS:

1.9 RESULT:

Thus the single phase AC voltage controller with R & RL loads is studied and we plotted the

waveforms of different firing angle.

1.10 PRE LAB QUESTIONS:-

1. Why should the two trigger sources be isolated?

2. What are the advantages and the disadvantages of phase control?

3. What is phase control?

4. What are the advantages of bidirectional controllers?

5. What is meant by duty cycle in ON-OFF control method?

1.11 POST LAB QUESTIONS:- 1. What type of commutation is used in this circuit?

2. What are the effects of load inductance on the performance of AC voltage controllers?

3. What is extinction angle?

4. What are the disadvantages of unidirectional controllers?

5. What are the advantages of ON-OFF control?

12

Exp. No.:2 Date:

DC JONES CHOPPER WITH R AND RL LOADS

2.1 OBJECTIVE:

To study the module and waveforms of a DC Jones chopper with R and RL loads.

2.2 RESOURCES:

S. No.Name of the

ApparatusRange Type Quantity

1

Jones chopper firing

circuit module and

power circuit module

- - 1





2.3 SPECIFICATIONS:

1. Input: 0 – 230V 1Φ AC supply.

2. Load R, & RL

3. Thyristors 25A, 1200V, type 25 RIA 120.

4. Diodes: 25A, 1200V.

5. Commutating Capacitor 25µF, 440V

6. MCB Two pole 230V/16A.

7. Fuses 16A HRC

2.4 PRECAUTIONS:





5. Make sure to connect firing pulses from the firing circuit to their respective SCRs in the power

circuit.

13

2.5 MODEL GRAPH: Voltage and Current waveforms in the Jones Chopper

t

`t

t

Ig1

Ig2

ISCR2

VSCR2

Vc

Ic

ISCR1

VSCR1

VL

t

t

t

t

t

t

14

2.6 PROCEDURE:

1. Switch On the mains supply to the firing circuit. Observe the trigger on by varying duty cycle

and frequency potentiometer by keeping the c switch in ‘INT’ position. Make sure the firing

pulses are proper be connecting to the power circuit.


3. Connect firing pulses from the firing circuit to the respective SCRs power circuit.

4. Initially set the input DC supply to 5V.

5. At the beginning, keep the ON/OFF switch in the firing circuit in OFF position.

6. Switch ON the DC supply and now ON the trigger pulses by open On/OFF switch in the firing

circuit.

7. Observe the DC chopped voltage waveform across load using oscilloscope.

8. If the commutation fails, pure DC voltage can be observed across the then switch OFF the DC

supply and trigger pulses. Check the connect and try again.

9. Observe the voltage waveform across load, capacitor, main SCR auxiliary SCR by varying the

duty-cycle potentiometer and frequency potentiometer, using oscilloscope.

10. Now, vary the DC supply up to the rated voltage, 30VDC.

11. Note down the readings in the TABULAR FORMS.

12. Draw the waveforms in the graph at different duty cycles and at different

Formula used:

Theoretical value = Ton/T100

T= Ton +Toff

15

2.7CIRCUIT DIAGRAM:

2.7.1 Circuit Diagram of DC Jones Chopper with RL Load

2.7.2Circuit Diagram of DC Jones Chopper with R Load

D1

–

+TA

L2L1

To CRO

T1

RV

DC Supply

16

2.8 TABULAR FORMS:

2.8.1 At F1 (middle)

S.

No.

Input

voltage

(Vin)

Time in milli sec. Duty

cycle

(%)

Output

voltage

(V0)

Theoretical

value =

Ton/T100Ton(ms) Toff(ms)

2.8.2 At F2 (maximum)

S.

No.

Input

voltage

(Vin)

Time in milli sec. Duty

cycle

(%)

Output

voltage

(V0)

Theoretical

value =

Ton/T100Ton(ms) Toff(ms)

2.9 RESULT:

Thus the module and waveforms of a DC Jones chopper with R and RL loads was studied.


1. What is a chopper? Where it is normally employed?

2. Explain the principle of operation of a chopper.

3. What are the control strategies used for a chopper?

4. What is time ratio control (TRC) of a chopper? How is it classified?

2.11 POSTLAB QUESTIONS:-

1. Why is forced commutation required in dc choppers?

2. What are the effects of turn on and turn off times of thyristor on the performance of the chopper.

3. What are the merits and demerits of this circuit?

4. What is current limit control of a chopper?

17

Exp. No.: 3 Date:

SINGLE PHASE PARALLEL INVERTER WITH R AND RL LOADS

3.1 OBJECTIVE:

To study the module and waveforms of a 1-Φ Parallel inverter with R and RL loads.

3.2 RESOURCES:

S. No.Name of the


1

1-Φ parallel inverter

firing module and

power circuit module

- - 1





3.3 SPECIFICATION:

1. Input 230V, 50Hz, 1-Φ AC supply.

2. Load R and RL.

3. Thyristors 10A, 600V.

4. Diodes 10A, 600V.

5. Capacitors 6.8µF, 100V.

7. Inductor 300mH, 2A.

9. Fuses 2A Glass fuse.

3.4 PRECAUTIONS:





5. Make sure to connect firing pulses form the firing circuit to their respective SCRs in the power

circuit.

6. Ensure to switch OFF the input supply first and then trigger pulses to short circuit.

18

3.5 MODEL GRAPH:

TRIGGER OUTPUTS

3.6 PROCEDURE:

1. Switch ON the mains supply to the firing circuit. Observe the trigger output in the firing circuit

by varying frequency potentiometer and by operating OFF switch. Make sure the firing pulses

are proper before connecting to the power circuit.


3. Connect firing pulses form the firing circuit to the respective SCRs in power circuit.

4. Connect the DC input from a 30V, 2A regulated power supply.

5. Switch ON the DC supply, set input voltage to 15V and switch ON the trigger pulses by

operating ON/OFF switch in the firing circuit.

6. Observe the voltage waveform across load using oscilloscope.

7. Vary the frequency and observe the voltage waveforms across load with without freewheeling

diode.

8. Draw the waveforms in the graph at different frequencies.

9. To switch off the inverter, switch OFF the input supply first and then trigger pulses.

10. Since the parallel inverter works on forced commutation, there is a chopper commutation

failure. If the commutation fails, switch off the DC supply and then trigger outputs. Check the

connections and try again.

T1

T2

+VDC

--VDC

19

3.7 CIRCUIT DIAGRAM

3.7.1 Single Phase Parallel Inverter with R load

RPS (0-30)VDC Supply

+

-

L

D1

T1

T2

D2

L

C 0VR-Lo

50,2A

RPS (0-30)VDC Supply

+

-

L

D1

T

T

D2

C 0V

RLLoad

50,150mH2A

3.7.2 Single Phase Parallel Inverter with RL load

20

3.8 TABULAR FORMS:

3.8.1For R Load:

S.

No.

Input

voltage

(Vin)

Time in milli sec. Amplitude

in (V)

Vm

Output

average

voltage

(V0)

Theoretical

output

frequency

in Hz

Ton(ms) Toff(ms)

3.8.2 For R-L Load:

S.

No.

Input

voltage

(Vin)

Time in milli sec. Amplitude

in (V)

Output

average

voltage

(V0)

Theoretical

output

frequency

in Hz

Ton(ms) Toff(ms)

V1 V2

3.9 RESULT:

Thus the module and waveforms of a 1-Φ Parallel inverter with R and RL loads was studied.

3.10PRE LAB QUESTIONS:-

1. What is parallel inverter? Why is it called so? 2. What is the purpose of capacitor in the parallel inverter? 3. What is the purpose of transformer in the parallel inverter? 4. IS the parallel inverter naturally commutated or force commutated? 5. What are the advantages of parallel resonant inverters?

3.11 POST LAB QUESTIONS:-

1. What is the purpose of the inductor in the parallel inverter? 2. During its operation, capacitor voltage reaches 2Vs. How? 3. What is the significance of the split phase transformer? 4. During operation, what is the voltage across primary winding of the transformer? 5. Capacitor current flows in how many modes of the operation of parallel inverter?

21

Exp. No.:4 Date:

SINGLE PHASE HALF CONTROLLED CONVERTER WITH R LOAD

4.1 OBJECTIVE:

To study the module and waveforms of a 1-Φ Half controlled converter with R load at different firing

angles.

4.2 RESOURCES:


1

1 Half controlled

converter power and

firing module

- - 1





4.3 SPECIFICATIONS:

1. Input : 1, 230V , 50Hz AC supply.

2. Load : R, RL

3. Thyristors : 25A, 1200V, type 25 RIA 120/TYN616.

4. Diode : 25A, 1200V, BY126/BY127.

5. MCB : Two pole 230V/16A

6. Fuses : 16A HRC.

7. Field Supply bridge rectifier : 10A, 600V.

8. Field Supply : 220V + 10%.

4.4 PRECAUTIONS:





5. If the output is zero even after all power connections, switch OFF the MCB and just

interchange AC input connections to the power circuit. This is to make the firing circuit and

power circuit to synchronize.

22

4.5 MODEL GRAPH:

0

0 π 2π 3π 4π

t (ms)

Vi (v)

VL (v)

t (ms)

0

VL (v)

t (ms)

t (ms)0

VL (v)

0t (ms)

Input Waveform

Output Waveform R and RL - Load at =00

Output Waveform R and RL -Load at =450



23

4.6 PROCEDURE:

1. Switch ON the main supply to the firing circuit. Observe the trigger output by varying firing

angle potentiometer and by operating ON/OFF switch and their phase sequence. Make sure the



3. Connect 30V tapping of the transformer secondary to the power circuit.

4. Connect firing pulses 0from the firing circuit to their respective SCRs in power circuit.

5. Switch ON the MCB and now switch ON the trigger pulses by operate ON/OFF switch in the

firing circuit.

6. Observe the output voltage waveforms across load and devices us oscilloscope.

7. Note down the input voltage, firing angle, Output voltage and output circuit reading in the

TABULAR FORMS.

8. Repeat the same for different input voltage up to max. voltage as provided in the isolation

transformer.

9. Repeat the same for R-L and RLE loads with and without freewheeling diode.

10. Draw the waveforms in the graph at firing angles 00, 450, 900, 1350 and 1800.

FORMULAE USED:

Output voltage V0 = Vdc = Vm/ (1 + cos )

24

4.7 CIRCUIT DIAGRAM:

P

N

1, 230V, 50Hz, AC

230V

0V 0V

30V

K1 K2

K2K1

A1 A2

A2A1

G1 G2

T1 T2

D2D1

2TYN616

21N4007

R LOAD150, 5A

4.7.1SINGLE PHASE HALF CONTROLLED CONVERTER WITH R LOAD

P

N

1, 230V, 50Hz, AC

230V

0V 0V

30V

K1 K2

K2K1

A1 A2

A2A1

G1 G2

T1 T2

D2D1

2TYN616

21N4007

R

L

LOAD150, 5A

0-150mH, 5A

4.7.2 SINGLE PHASE HALF CONTROLLED CONVERTER WITH RL LOAD

25

S. No. Input

voltage

(V)

Firing

angle (a)

Output voltage

(V)

Output

Theoretical

voltage

4.8 TABULAR FORMS: for R load

S. No. Input

voltage

(V)

Firing

angle (a)

Output voltage

(V)

Output

Theoretical

voltage


4.10 RESULT:

Thus the single phase half controlled converter with R and RL load is studied and also we

plotted the waveforms of different firing angles.


1. What is the delay angle control of converters? 2. What is natural or line commutation? 3. What is the principle of phase control? 4. What is extinction angle? 5. Can a freewheeling diode be used in this circuit and justify the reason?

4.12 POSTLAB QUESTIONS:- 1. What is conduction angle? 2. What are the effects of adding freewheeling diode in this circuit? 3. What are the effects of removing the freewheeling diode in single phase semi converter? 4. Why is the power factor of semi converters better than that of full converters? 5. What is the inversion mode of converters?

26

Exp. No.: 5 Date:

PSPICE SIMULATION OF SINGLE PHASE FULL CONVERTER AND SINGLE PHASE AC

VOLTAGE CONTROLLER USING RLE LOADS

5.1OBJECTIVE:

To study the output waveforms of single-phase full converter using RLE loads and single-phase AC

voltage controller using RLE loads using PSPICE simulation.

5.2 RESOURCES: PSPICE Software

AC Model of SCR:

F1= P1Ig + P2Ia

= 50Ig + 11Ia

27

5.3 Circuit diagram of single phase full converter:

5.4Circuit file for Single phase full converter:

VS 10 0 SIN (0 169.7V 60HZ)

VG1 6 2 PULSE (0V 10V 2777.8US 1NS 1NS 100US 16666.7US)




R 2 4 10

L 4 5 20MH

C 2 11 793UF

RX 11 3 0.1

VX 5 3 DC 10V

VY 10 1 DC 0V

* SUBCIRCUIT CALLS FOR THYRISTOR MODEL

XT1 1 6 2 SCR

XT2 0 8 2 SCR

XT3 3 7 0 SCR

XT4 3 9 1 SCR

. SUBCKT SCR 1 3 2

S1 1 5 6 2 SMOD

RG 3 4 50

VX 4 2 DC 0V

28

VY 5 2 DC 0V

RT 2 6 1

CT 6 2 10UF

F1 2 6 POLY (2) VX VY 0 50 11

.MODEL SMOD VSWITCH (RON=0.01 ROFF=10E+5 VON=0.1V VOFF=0V)

.ENDS SCR

.TRAN 10US 35MS 16.67MS

.PROBE

.OPTIONS ABSTOL=1.00U RELTOL=1.0M VNTOL=0.1 ITL5=10000

.FOUR 120HZ I (VX)

.END

29

5.5 Circuit diagram of single phase Ac Voltage Controller:

5.6 Circuit file for Single phase ac voltage controller:

VS 10 0 SIN (0 169.7V 60HZ)



R 4 5 2.5

L 5 6 6.5MH

VX 6 0 DC 0V

CS 1 7 0.1UF

RS 7 4 750

* SUBCIRCUIT CALLS FOR THYRISTOR MODEL

XT1 1 2 4 SCR

XT2 4 3 1 SCR

. SUBCKT SCR 1 3 2

S1 1 5 6 2 SMOD

RG 3 4 50

VX 4 2 DC 0V

VY 5 2 DC 0V

30

RT 2 6 1

CT 6 2 10UF

F1 2 6 POLY (2) VX VY 0 50 11

.MODEL SMOD VSWITCH (RON=0.01 ROFF=10E+5 VON=0.1V VOFF=0V)

.ENDS SCR

.TRAN 10US 33.33MS

.PROBE

.OPTIONS ABSTOL= 1.00N RELTOL = 1.0M VNTOL=1.0M ITL5=10000

.FOUR 60HZ V (4)

.END

5.7RESULT :

The output waveforms of single-phase full converter using RLE loads and single-phase AC voltage

controller using RLE loads using PSPICE simulation are studied.


1. What is the difference between a diode rectifier and a thyristor rectifier?

2. What is controlled rectification?

3. What is meant by firing angle of a converter?

4. What is an ac voltage controller?

5. How does the load inductance effect the conduction angle of a controller?


1. What is an integral cycle control?

2. What is phase control?

3. What is discontinuous in thyristor power converters?

4. How is it achieved in thyristor power converters?

5. What are the effects of load inductance on the performance of a power converter?

31

Exp. No.:6 Date:

GATE FIRING CIRCUITS FOR SCRs

6.1 OBJECTIVE:

To study the following various firing schemes for triggering SCRs when they are different converter

topologies employing line commutation.

1. Resistance firing circuit.

2. Resistance capacitance (RC) firing circuit.

3. UJT firing scheme.

6.2 RESOURCES:

S. No.Name of the


1 R & RC power module - - 1

2 UJT power module - - 1

3 R load 50, 2A - 1

4 CRO & probe Dual - 1


6.3 SPECIFICATIONS:

1. SCRs : 400V, 4A, type 106 D

2. Diodes : 1N4007

3. Diacs : D3202U

4. Zeners : 20V, 1W

5. UJTs : 2N2646

6. Pulse transformer : 1:1:1

6.4 PRECAUTIONS:

1. Make sure all the connections are tight.

2. Ensure all the controlling knobs are kept in fully counterclockwise position before starting

experiment.


32

6.5 MODEL GRAPH:

Input Waveform

Output Waveform =0 0

Output Waveform =90 0

0

0

0

0

0 π 2π 3π 4π t (ms)

Vi (v)

VL (v)

VSCR (v)

VL (v)

VSCR (v)

t (ms)

t (ms)

t (ms)

t (ms)

33

6.6 PROCEDURE:

(a). R firing circuit:


2. Connect a load rheostat of 50Ω, 2 A between the load points

3. Switch ON the power supply

4. Vary the control pot and observe the voltage waveforms across load and at different points in

the circuit using oscilloscope.

5. Draw the waveforms in the graph at firing angles 00, 450, 900, 1350.

6. Bring the pot to the original position.

7. Switch OFF the power Supply.

(b). RC firing circuit:




4. Vary the control pot and observe the voltage waveforms across load and at different points

in the circuit using oscilloscope.




(c). UJT firing circuit:




4. Vary the control pot and observe the voltage waveforms across load and at different points

in the circuit using oscilloscope.




FORMULAE USED:

Firing Angle = )(deg*

10*10

1803

0

reest

34

6.7 CIRCUIT DIAGRAM

6.8 TABULAR FORMS:

A. i. Resistance Firing Circuit: -

ii. Resistance Firing Circuit: - across SCR and Load

Sl.

No.

Resistance (R) in

Ω

Firing angle

() in s

1.

2.

3.

4.

5.

Sl.

No.

(R) in

Ω

Firing

angle

() in

s

Ton Toff Amplitude

1.

2.

3.

4.

5.

K1

GATE FIRING CIRCUIT FOR SCR’S-RESISTANCE FIRING CIRUCIT

KA

R LOAD

50, 2A

20V, 2A AC

R

RC

DRg

T1

TYN616

1N4007

35

B. i. Resistance Capacitance Firing Circuit: -

Sl.

No.

Resistance (R)

in Ω

Capacitance (c)

in Fd

Firing angle ()

in s

1.

2.

3.

4.

5.

ii. Resistance Capacitance Firing Circuit: -

Sl.

No.

(R) in

Ω

Firing

angle

() in

s

Ton Toff Amplitude

1.

2.

3.

4.

5.

K1

A1

G1

GATE FIRING CIRCUIT FOR SCR’S-RESISTANCE CAPACITANCE (RC) FIRING CIRUCIT

KA

R LOAD

50, 2A

20V, 2A AC

R

RC

D2Rg

T1

TYN616

1N4007

D1

C4.7F

36

C. i. UJT Firing Circuit: -

S.

No.

Resistance (R) in

Ω

Firing angle

() in s

1.

2.

3.

4.

5.

ii. UJT Firing Circuit: -

Sl.

No.

(R) in

Ω

Firing

angle

() in

s

Ton Toff Amplitude

1.

2.

3.

4.

5.

K

A

P

N

1, 230V, 50Hz AC

D3D1

D4 D2

R

CZD

R

RC

C

UJT2N2646

Pulse TFR1:1:1

T1

A

GK

AC20V, 2A

RLOAD

50, 2A

20V, 2A

4.7F

1000F

GATE FIRING CIRCUIT FOR SCR’S-UJT FIRING CIRUCIT

37

6.9 RESULT:

Thus the different types of gate firing circuits of SCR’s i. R Firing circuit, ii. RC Firing circuit and iii.

UJT firing circuit is studied and also plotted its waveforms.


1. UJT triggering circuit is also known as?

2. Types of triggering circuit?

3. What is the purpose of series resistor?

4. What is the condition for triggering the circuit?

5. What is the function of pulse transformer in firing circuit?


1. Explain how synchronization of the triggering circuit with the supply voltage across SCR is

achieved?

2. How can the capacitor charging be controlled?

3. What is the maximum value of firing angle which can be obtained from the circuit?

4. How is the output power to the triggering circuit controlled?

5. Compare UJT triggering circuit with RC firing circuit?

38

Exp. No.:7 Date:

SINGLE PHASE FULLY CONTROLLED BRIDGE CONVERTER WITH R AND RL LOADS

7.1 OBJECTIVE:

To study the module and waveforms of a 1-Φ Full Bridge Converter with RL and RL loads.

7.2 RESOURCES:


1

1 Full bridge

controlled converter

power and firing

module

- - 1





7.3 SPECIFICATIONS:

1. Input : 1, 230V 50Hz, AC supply.

2. Load : R and RL loads.

3. Thyristors : 16A, 1200V, type 16 TTS/TYN616

4. Diode : 25A, 1200V, BY126/BY127


6. Fuses : 16A HRC.

7. Field Supply bridge rectifier: 10A, 600V.


7.4 PRECAUTIONS:








39

7.5 MODEL GRAPH:

Input Waveform

0

0 π 2π 3π 4π

t (ms)

Vi (v)

VL (v)

t (ms)

0

VL (v)

t (ms)

t (ms)0

VL (v)

0

VL (v)t (ms)

Output Waveform R- Load at =00


R- Load at =900

R- Load at =1350

t (ms)0

VL (v) RL- Load at =450

0

VL (v)

t (ms)

RL- Load at =900

40

7.6 PROCEDURE:


angle potentiometer and by operating ON/OFF switch their phase sequence. Make sure the




4. Connect firing pulses from the firing circuit to their respective SCRs in power circuit.


firing circuit.



TABULAR FORMS.


transformer.



FORMULAE USED:

Average output voltage – R load, VAvg=

cos1

Vm

Average output voltage – RL load, VAvg=

cos

Vm2

41

7.7CIRCUIT DIAGRAM :

7.8TABULAR FORMS:

a. For R load

S.No. Input voltage (V)Firing

angle ()

Output voltage

(V)

Theoretical

Output

voltage (V)

P

N

1, 230V, 50Hz, AC

230V

0V 0V

30V

K1 K3

A1 A3

G1 G3

T1 T3

4TYN616

RLOAD150, 5A

SINGLE PHASE FULL CONTROLLED BRIDGE CONVERTER WITH R LOAD

K4 K2

A4 A2

G4G2

T4 T2

42

b. For RL load without freewheeling diode:


angle ()

Output voltage

(V)

Theoretical

Output

voltage (V)

P

N

1, 230V, 50Hz, AC

230V

0V 0V

30V

K1 K3

A1 A3

G1 G3

T1 T3

4TYN616

R

L

LOAD150, 5A

0-150mH, 5A

SINGLE PHASE FULL CONTROLLED BRIDGE CONVERTER WITH RL LOAD

K4 K2

A4 A2

G4G2

T4 T2

43

c. For RL load with freewheeling diode:


angle ()

Output voltage

(V)

Theoretical

Output

voltage (V)


P

N

1, 230V, 50Hz, AC

230V

0V 0V

30V

K1 K3

A1 A3

G1 G3

T1 T3

4TYN616

R

L

LOAD150, 5A

0-150mH, 5A

SINGLE PHASE FULL CONTROLLED BRIDGE CONVERTER WITH FREEWHEELING DIODE FED RL LOAD

K4 K2

A4 A2

G4G2

T4 T2

K

A

FD

44

7.10 RESULT:

Thus the single phase Full controlled bridge converter with R and RL load is studied and also

plotted the waveforms of different firing angles.


1. State the type of commutation used in this circuit?

2. What will happen if the firing angle is greater than 90 degrees?

3. What are the performance parameters of rectifier?

4. What are the advantages of three phase rectifier over a single phase rectifier?

5. What is the difference between half wave and full wave rectifier?

7.12POST LAB QUESTIONS:-

1. If firing angle is greater than 90 degrees, the inverter circuit formed is called as?

2. What is Dc output voltage of single phase full wave controller?

3. What are the effects of source inductance on the output voltage of a rectifier?

4. What is commutation angle of a rectifier?


45

Exp. No.:8 Date:

STUDY OF FORCED COMMUTATION CIRCUITS

8.1 OBJECTIVE: To Verify the different types of forced commutation circuits by connecting a

resistive load.

8.2 RESOURCES:

S.No EQUIPMENT Qty

1. Forced commutation Kit 1

2. Regulated Power Supply 1

3. Rheostat 2

4. CRO 1

5. Patch cards

8.3 PRECAUTIONS:








46

8.4 MODEL GRAPHS:

CLASS-A COMMUTATION:

CLASS-B COMMUTATION:

CLASS-C COMMUTATION:

CLASS-D COMMUTATION:

47

8.5 CIRCUIT DIAGRAM:

CLASS-A COMMUTATION: CLASS-B COMMUTATION:

CLASS-C COMMUTATION: CLASS-D COMMUTATION:

R

D

–

+TA

L

T1

(0-30V)T1 T2

C

R1 R2

(0-15V)

R

LT

(0-15V)

C

To CRO

R

L

T1

(0-15V) C To CRO

48

8.6 PROCEDURE:

CLASS-A COMMUTATION:

1. Connect the circuit as shown in the circuit.

2. Connect Trigger output T1 to gate and cathode of SCR T1

3. Switch on the DC supply to the power circuit and observe the voltage waveform across load by

varying the frequency potentiometer.

4. Repeat the same for different values of L, C and R.

CLASS-B COMMUTATION:


2. Connect Trigger output T1 to gate and cathode of SCR T1

3. Switch on the DC supply to the power circuit and observe the voltage waveform across load by

varying the frequency potentiometer.

4. Repeat the same for different values of L,C and R.

Note: Same procedure for Class-A and Class-B Commutation.

CLASS-C COMMUTATION:


2. Connect T1 and T2 from firing circuit to gate and cathode of Thyristor T1 and T2.

3. Observe the waveforms across R1,R2 and C by varying frequency and also duty cycle

potentiometer.

4. Repeat the same for different values of C and R.

CLASS-D COMMUTATION:


2. Connect T1 and T2 gate pulse from the firing circuit to the corresponding SCR’s in the power

circuit.

3. Initially keep the trigger ON/OFF at OFF position to initially charge the capacitor, this can be

observed by connecting CRO across the capacitor.

4. Now switch ON the trigger output switch and observe the voltage waveform across the load

T1, T2 and capacitor. Note down the voltage waveforms at different frequency of chopping

and also at different duty cycle.

5. Repeat the experiment for different values of load Resistance, commutation inductance and

capacitance.

49

8.7 TABULAR FORMS:

S.No. Classes Time in milli sec. Amplitude in Volts

Ton(ms) Toff(ms) VL VSCR Vc

+V –V

A

A


Ton(ms) Toff(ms) VL VSCR VC

+V –V +V –V

B

B

B



V1 V2 +V –V +V –V

C

C

C



+V –V +V –V

D

D

D

50

8.8 RESULT: The operations of class- A, B, C, and D are observed.


1. What is meant by commutation?

2. List out the commutation techniques?

3. Why is forced commutation required in dc choppers?

4. Explain the working principle of type E Chopper?


1. What is a four quadrant chopper?

2. What is the commutation angle of a rectifier?

3. What are the effects of source inductances on the output voltage of a rectifier?

4. What is a commutation of diodes?

51

Exp. No.:9 Date:

SINGLE PHASE CYCLO CONVERTER WITH R & RL LOADS

9.1OBJECTIVE:

To verify the operation of single phase Cyclo Converter with R and RL Loads and to observe

the output and input waveforms

9.2 RESOURCES:

S.No EQUIPMENT Qty

1.I-φ Center tapped

Transformer1

2.I-φ Cyclo Converter power

circuit with firing unit1

3. Rheostat 1

4. Inductive load 1

5. Voltmeter(MI) 1

6. CRO with (1:10) Probe 1

7. Patch cards 1 set

9.3 PRECAUTIONS:








52

9.4 MODEL GRAPHS:

1/2f cycloconverter waveforms

1/3f cyclo converter waveforms

1/4f cycloconverter waveforms

53

9.5 CIRCUIT DIAGRAMS:

center tapped transformer

T4

T3

To CRO

N

Ph

T1

T2L

R1-Φ, 230V 50Hz AC Supply

Fig-2Fig2-Single phase cyclo converter with RL-load

center tapped transformer

1-Φ, 230V 50Hz AC Supply

T4

T3

To CROR

N

Ph

T1

T2

Fig1-Single phase cyclo converter with R-load

54

9.6 PROCEDURE:

A) For R-Load:

1. Connect the circuit as shown in figure.

2. Verify the connections from the lab instructor before switch on the supply.

3. Keep the rheostat position value given by the lab instructor

4. Switch ON the supply and note down the frequency of input voltage from the CRO.

5. Set the frequency division switch at 2 and note the readings of time period of output

voltage waveform for different set of firing angles

6. Calculate the practical value of output frequency by reciprocating the value of time

period and theoretical value of frequency will be found from frequency division setting

7. Repeat the above process from step 5 to 6 for frequency division of 3 and 4.

B). For RL-Load:

1. Connect the circuit as shown in figure.

2. Connect an inductance of given value in series with the load resistance.

3. Verify the connections from the lab instructor before switch on the supply.

4. Keep the rheostat position value given by the lab instructor

5. Switch ON the supply and note down the frequency of input voltage from the CRO.

6. Set the frequency division switch at 2 and note the readings of time period of output

voltage waveform for different set of firing angles

7. Calculate the practical value of output frequency by reciprocating the value of time

period and theoretical value of frequency will be found from frequency division

setting

8. Repeat the above process from step 5 to 6 for frequency division of 3 and 4.

55

9.7 TABULAR FORMS:

A) For R-Load:

The input voltage Vph = V (As given by the instructor)

Value of load resistance RL= Ω(As given by the instructor)

Input frequency = Hz

S.NO. Frequency

division

Firing angle(α)

in degrees

Time period in

msec

Frequency

(practical)

Frequency

(theoretical)

B) For RL-Load:

The input voltage Vph = V (As given by the instructor)

Value of load resistance RL= Ω(As given by the instructor)

Value of Load inductance L= mH(As given by the instructor)

S.NO. Frequency

division

Firing angle(α)

in degrees

Time period in

msec

Frequency

(practical)

Frequency

(theoretical)

9.8 RESULT: The operation of I-φ cyclo converter is verified and the theoretical and practical values

of output frequencies at different frequency divisions are found both for R & RL loads


1. On what principle does cycloconverter works?

2. What is the major difference between AC voltage controller and cycloconverter?

3. What type of commutation is employed in cycloconverter?


1. What is the purpose of reactor connected in cycloconverter?

2. What happens to the output if the frequency of operation is beyond suggested limit?

3. What are the applications of cycloconverter?

56

Exp. No.:10 Date:

PSPICE SIMULATION OF SINGLE PHASE INVERTER WITH PWM CONTROL

10.1 OBJECTIVE: To study the output of single phase Inverter with PWM control using PSPICE

simulation.

10.2 Resources: PSPICE Software

10.3CIRCUIT DIAGRAMS OF SINGLE PHASE INVERTER WITH PWM CONTROL

(a) Circuit

(b) PWM generator

57

(c) carrier and reference signals

10.4 CIRCUIT MODEL FOR SINGLE PHASE INVERTER WITH PWM CONTROL

VS 1 0 DC 100V

VR 17 0 PULSE (50V 0V 0 833.33US 833.33US 1NS 16666.67US)

RR 17 0 2MEG

VC1 15 0 PULSE (0 -30V 0 1NS 1NS 8333.33US 16666.67US)

RC1 15 0 2MEG

VC3 16 0 PULSE (0 -30V 8333.33US 1NS 1NS 8333.33US 16666.67US)

RC3 16 0 2MEG

R 4 5 2.5

L 5 6 10MH

VX 3 4 DC 0V

VY 1 2 DC 0V

D1 3 2 DMOD

D2 0 6 DMOD

D3 6 2 DMOD

D4 0 3 DMOD

.MODEL DMOD D (IS=2.2E-15 BV=1800V TT=0)

Q1 2 7 3 QMOD

Q2 6 9 0 QMOD

Q3 2 11 6 QMOD

Q4 3 13 0 QMOD

.MODEL QMOD NPN(IS=6.734F BF=416.4 CJC=3.638P CJE=4.493P)

RG1 8 7 100

RG2 10 9 100

RG3 12 11 100

RG4 14 13 100

* SUBCIRCUIT CALL FOR PWM CONTROL

XPW1 17 15 8 3 PWM

58

XPW2 17 15 10 0 PWM

XP3 17 16 12 6 PWM

XP4 17 16 14 0 PWM

* SUBCIRCUIT FOR PWM CONTROL

.SUBCKT PWM 1 2 3 4

R1 1 5 1K

R2 2 5 1K

RIN 5 0 2MEG

RF 5 3 100K

RO 6 3 75

CO 3 4 10PF

E1 6 4 0 5 2E+5

.ENDS PWM

.TRAN 10US 16.67MS 0 10US

.PROBE

.OPTIONS ABSTOL 1.00N RELTOL=0.01 VNTOL=0.1 ITL5=20000

.FOUR 60HZ V (3, 6)

.END

10.5 RESULT:

PSPICE simulation of single phase Inverter with PWM control is studied and output

waveforms are observed.


1. What are the disadvantages of PWM control?

2. What are the methods of reduction of harmonic content?

3. What is meant by PWM control?

4. What are the main classifications of inverter?


1. What is meant by inverter?

2. What is McMurray Inverter?

3. How is the inverter circuit classified based on commutation circuitry?

4. What are the applications of an inverter?

59

Exp. No.:11 Date:

PSPICE SIMULATION OF BUCK CHOPPER AND RESONANT PULSE COMMUTATION

11.1OBJECTIVE:

Study of resonant pulse commutation circuit and Buck chopper with PSPICE simulation

11.2 RESOURCES: PSPICE Software

11.3 CIRCUIT DIAGRAM OF RESONANT PULSE COMMUTATION

11.4 CIRCUIT FILE FOR RESONANT PULSE COMMUTATION

VS 1 0 DC 12V

VY 1 2 DC 0V

VG 8 0 PULSE(0V 20V 0 1NS 1NS 12.24US 40US)

RB 8 7 250

R 6 0 10

LE 2 3 25.47UH

CE 3 0 1.38UF

C 3 4 0.0958UF

L 5 6 445.63UH

VX 4 5 DC 0V

Q1 3 7 0 MODQ1

.MODEL MODQ1NPN (IS=6.734F BF=416.4 ISE=6.734F BR=.7371

+ CJE=3.637P MJC=0.3085 VJC=.75 CJE=4.493P MJE=.2593 VJE=.75

+ TR=239.5N TF=301.2P)

.TRAN 2US 300US 180US 1US UIC

.PROBE

.OPTIONS ABSTOL=1.00N VNTOL=0.1 ITL5=20000

.END

60

11.5 Circuit diagram of buck converter

11.6 CIRCUIT MODEL FOR BUCK CHOPPER

VS 1 0 DC 110V

VY 1 2 DC 0V

VG 7 3 PULSE (0V 20V 0 0.1NS 0.1 NS 27.28US 50US

RB 7 6 250

LE 3 4 681.82UHCE 4 0 8.33UF IC=60V

L 4 8 40.91UH

R 8 5 3

VX 5 0 DC 0V

DM 0 3 DMOD

.MODEL DMOD D (IS=2.2E-15 BV=1800V TT=0)

Q1 2 6 3 QMOD

.MODEL QMOD NPN (IS=6.734F BF=416.4 BR=.7371 CJC=3.638P

+ CJE=4.493P TR=239.5N TF=301.2P)

.TRAN 1US 1.6MS 1US UIC

.PROBE

.OPTIONS ABSTOL=1.00N RELTOL=0.01 VNTOL=0.1 ITL5=50000

.FOUR 20KHZ I(VY)

.END

11.7 RESULT: PSPICE simulation of resonant pulse commutation circuit and Buck chopper is

studied and output waveforms are observed.

61


1. What is PSPICE?

2. What is the principle of Buck Chopper?

3. What are the different types of chopper with respect to commutation process?


1. What are the applications of dc chopper?

2. What is commutation angle or overlap?

3. What are the advantages of current commutated chopper?

62

Exp. No.:12 Date:

STUDY OF CHARACTERISTICS OF SCR, MOSFET & IGBT

A. STUDY THE CHARACTERISTICS OF SCR.

12.1 OBJECTIVE:

To plot the forward characteristics of SCR and the find the forward Resistance.

12.2 RESOURCES:

S. No.Name of the


1 SCR TYN 616 - 1

2 Ammeter (0 – 100)mA MC 1

3 Ammeter (0 – 25)mA MC 1

4 DMW (0 – 5)V MC 1

5 RPSU (0 – 30)V DC 2

6 Connecting wires - - As required

12.3 PROCEDURE:


2. Keep E1 & E2 (RPSU) at minimum position.

3. Set load potentiometer in minimum position.

4. Switch ON the supply and to set some value of Vak voltage (5V to 7V).

5. BY adjusting E2 and set some value of IG (constant).

6. Slowly vary E1 and note down the corresponding Vak and meter readings.

7. By varying E2 (or) Gate current potentiometer R2, adjust IG to some other values (constant).

8. Repeat the same procedure step 6 to obtain the different values of Vak and Ia.

9. Bring back everything to minimum position then switch off the supply.

10. Draw the graph Vak Vs Ia.

11. Then from the forward characteristics take the slope and find out forward resistance by using

the formulae

Rf = )(

I

V

a

ak

63

12.4TABULAR FORMS:

IG1 =__________ (mA)

S.No. VAK (volts) IA (mA)

IG2 = ________ (mA)

S.No. VAK (volts) IA (mA)

V2

RPS(0 –30V)

+ Ia -R1 = 1kΩ

(0-100mA)mc

Vak (0-5V)mc

+

-

V1

RPS(0 –30V)

+

-

+

-

R2 + -Ig

A

KG

TYN 616

(0-25mA)mc

STUDY OF CHARACTERISTICS OF SCR

64

12.5 MODEL GRAPH:

12.6 RESULT:

Thus the characteristics of SCR’s is studied and we plotted the forward characteristics of

SCR’s also found the forward resistance, RF=____ ()

Ia(ma)

IA2

IA1

VAK1 VAk2

VBO1 VBO2

IG IG

IG1 >

IG2

IL

IH

O VAK (Volts)

65

B. TO STUDY THE CHARACTERISTICS OF MOSFET

12.7 OBJECTIVE:

To plot the transfer characteristics and drain characteristics of MOSFET.

12.8 RESOURCES:


1 MOSFET IRF 740 - 1

2 Ammeter (0 – 500)MA MC 1

3 Voltmeter (0 – 20V) MC 1


5 RPS (0 – 30)V DC 2


12.9 PROCEDURE:

a. Transfer characteristics:-


2. Keep E1 &E2 (RPS) at minimum position initially.

3. Switch on the power supply.

4. Set E1 to some voltage (constant) and note down the readings of ID AND Vgs in steps by

adjusting E2 in step of 0.5 volt.

5. Bring back E1 & E2 to minimum position and switch off the power supply.

6. Plot the graph Vgs Vs ID.

FORMULAE USED:

Trans conductance (GM) = Change in Drain current / Change in Gate source voltage

= ΔID/ΔVGS

66

12.10TABULAR FORMS:

Trans conductance characteristics: VDS = _____ (V)

S.No. ID (A) VGS (V)

b. Drain Characteristics:

12.11PROCEDURE:


2. Switch ON the supply.

3. Initially set some value of VGS by adjusting E2.

4. Slowly vary E1 and note down the readings of ID and ‘VDS’

5. Set some other values of VGS and repeat the procedure step 4.

6. Bring back E1 and E2 position in minimum and switch off the power supply.

7. Plot the graph ID Vs VDS

FORMULAE USED:

Drain Resistance (RD) = ΔVDS/ΔID

67

12.12 TABULATION:

Drain characteristic:- VGS = _________(V)

S.No. ID (A) VDS (V)

V2

RPS(0-30V)

+ Id-

R1

(0-500mA)mc

(0-50V)mcVds

+

-

V1

RPS(0 –30V)

+

-

+

-

A

SG

IRF 740

D

Vgs

+

-

(0-20V)mc

STUDY OF CHARACTERISTICS OF MOSFET

68

12.13 MODEL GRAPH:

TRANS CONDUCTANCE CHARACTERISTICS

ID

V DS = 15V

ID

(on)

V GS (Th) V GS (on) V DS

3.5V

DRAIN CHARACTERISTICS

ID in mA

V GS = 3.6V

V GS = 3.55VV GS = 3.5V

V DS

12.14RESULT:

Thus the characteristics of MOSFET is studied and we plotted the Trans conductance and drain

characteristics of MOSFET and also found the Trans conductance, Gm=____ ( ), Drain Resistance

Rd=______ ()

69

C. STUDY CHARACTERISTICS OF IGBT

12.15OBJECTIVE:

To obtain transfer and output characteristics of IGBT.

12.16 RESOURCES:

S. No.Name of the


1 IGBT IRGBC 205 - 1

2 Ammeter (0 – 500)MA MC 1



5 RPS (0 – 30)V DC 2


12.17 PROCEDURE:

Transfer characteristics:

1. Make connection as per the circuit diagram.

2. Set E1& E2 (RPS) to minimum position Initially.

3. Switch ON the supply.

4. Set some value of VCE (constant) by adjusting E1.

5. Vary E2 in steps and note down the corresponding reading of VGE and IC.

6. Bring back E1 & E2 to original position and switch off the power supply.

7. Plot the graph VGE Vs IC.

O/P or Collector characteristics:


2. Set some value of VGE (constant) and by adjusting E2.

3. Slowly vary E1 and note down the readings of VCE and IC values.

4. For some other value of VGE (constant), repeat the procedure step 3.

5. Bring back E1 & E2 to minimum position and switch off the power supply.

6. Plot the graph VCE Vs IC.

70

12.18 TABULAR FORMS:-

a. Transfer characteristics:

VCE = _________ (V)

S.No. VGE (V) IC (mA)

V2

RPS(0 –30V)

+ Ic -R1

(0-500mA)mc

(0-50V)mcVce

+

-

V1

RPS(0 –30V)

+

-

+

-

E

G

IRBGC 20S C

Vge

+

-

(0-20V)mc

STUDY OF CHARACTERISTICS OF IGBT

71

b. O / P or collector characteristics:

VGE = _________ (V)

S.No. VCE (V) IC (mA)

12.19MODEL GRAPH:

TRANSFER CHARACTERISTICS

IC

V CE = 15V

IC

(on)

V CE (Th) V CE (on) V CE

5V

COLLECTOR CHARACTERISTICS

IC in V GE = 5.25V mA

V GE = 5.2V

V GE = 5.15V

V GE = 5.1V

V CE

12.20 RESULT:

Thus the characteristic of IGBT is studied and we plotted the Transfer and collector

characteristics of IGBT.

72

Exp. No.:13 Date:

SINGLE PHASE SERIES INVERTER WITH R AND RL LOADS

13.1 OBJECTIVE:

To study the operation of Single-phase series inverter with R and RL loads and plot its output

waveform.

13.2 RESOURCES:

S.No. ITEM RANGE TYPE QUANTITY

1 Series inverter power circuit kits 1 Ф ,230 V , 2 A 1

2 Series inverter firing circuit kit 1 Ф ,230 V , 2 A 1

3 Loading rheostat 100 / 2A 1


5 Regulated power supply (0 – 30 V) / 2 A 1

6 CRO 20 MHZ 1

7 Patch chords 15

13.3 MODEL GRAPH (SERIES INVERTER):

eo

ec2

ec1

T2

T1

t

t

t

t

t

73

13.4 PROCEDURE (SERIES INVERTER) :


2. Switch on the thyristor firing circuit

3. Keep the frequency knob of the firing circuit kit below the resonance Frequency of power

circuit kit

4. Switch on the DC power supply connected to the power circuit kit and Switch on the firing

circuit kit

5. Vary the frequency knob of the firing circuit kit

6. Observe the waveform from the CRO.

7. Repeat the same procedure for different values of L,C and load resistance.

8. Switch of the power supply and disconnect the connection

9. Calculate the frequency of the output waveform.

13.5 CIRCUIT DIAGRAM -SERIES INVERTER

D2T2

T1 (0-30V), M.ID1

(0-30)V RPS

L1

L2

LOAD

CRO

C1

C2

FUSE2A

V

74

13.6 TABULAR FORMS (SERIES INVERTER):

RESONANCE FREQUENCY = ____________: FIRING ANGLE = __________

S.No. Input Voltage

(Vi) Volts

Frequency Of Firing

Circuit (Hz)

Output Voltage

Vo (Volts)

13.7 RESULT:

Thus a single-phase series inverter operation was studied and its output waveform was plotted.


1. What is series inverter?

2. What are the advantages of basic series inverter?

3. Compare basic &modified series inverter?


1. What is the condition for resonant circuit behave like a capacitive load and inductive load in

series resonant inverter

2. What are the drawbacks of a basic series inverter?

3. What are the applications of series inverters?

4. Why are the inductors L1, L2 and why are two capacitors needed?

75

Exp. No.:14 Date:

THREE PHASE HALF CONTROLLED BRIDGE CONVERTER WITH R LOADS.

14.1 OBJECTIVEThe objective of Experiment is to analyze the operation (Switching) of three phase half

controlled rectifiers with resistive load.

14.2 RESOURCES:


1

3 Half controlled

converter power and

firing module

- - 1




14.3 SPECIFICATIONS:

Input Supply : 415V / 3ph. Supply for phase synchronization and 230V, 50Hz Single phase supply for the power supplyOutput : Six pairs of pulse transformer isolated trigger pulses.Gate drive current : 230mA.Gate Voltage : Open circuit- 5.1V, SCR LOAD-1.2V.Gate pulse width : Fixed 6.3 msec.Firing angle control : Internal 180° to 0° phase control by Potentiometer

External 180° to 0° phase control obtained by external control voltage between Vc and GND.

Test points : R, Y, B isolated signals for monitoring with respect to GND 1 to 8 – provide the test signals at various points of the trigger circuit.

14.4 PRECAUTIONS:








76

14.5 Waveform:

14.6 Circuit diagram:

77

14.7 PROCEDURE :1. Connect the three-phase half wave controlled rectifier circuit shown in Fig.(1) on the power electronic trainer. 2. Turn on the power. 3. By use oscilloscope, plot the input and output waveforms on the same graph paper" same axis". 4. Measure the average and RMS output voltage by connect the AVO meter across load resistance. 5. Turn off the power6. Use an inductive load. With L=10mH measure the output voltage and plot the output waveform. 7. Repeat step 6 with L=100mH measure the output voltage and plot the output waveforms. 8. Repeat step 6 & 7 with connect the freewheeling diode across the load

14.8 TABULAR FORMS: 1. for R load

S. No. Input

voltage

(V)

Firing

angle (a)

Output voltage

(V)

Output

Theoretical

voltage

14.9 Result:

Thus the operation (Switching) of three phase half controlled rectifiers with resistive load was studied.


1. What is the delay angle control of converters?

2. What is natural or line commutation?

3. What is extinction angle?

4. Can a freewheeling diode be used in this circuit and justify the reason?

14.11 POSTLAB QUESTIONS:-

1. What is conduction angle?

2. What are the effects of adding freewheeling diode in this circuit?

3. What are the effects of removing the freewheeling diode in three phase semi converter?

78

Exp. No.:15 Date:

SINGLE PHASE BRIDGE CONVERTER WITH R AND RL LOADS.

15.1OBJECTIVE:

To study the module and waveforms of a 1-Φ Bridge Converter with RL and RL loads.

15.2 RESOURCES:


1

1 Full bridge

controlled converter

power and firing

module

- - 1





15.3 SPECIFICATIONS:




4. Diode : 25A, 1200V, BY126/BY127


6. Fuses : 16A HRC.

7. Field Supply bridge rectifier: 10A, 600V.


15.4 PRECAUTIONS:








79

15.5 MODEL GRAPH:

Input Waveform

0

0 π 2π 3π 4π

t (ms)

Vi (v)

VL (v)

t (ms)

0

VL (v)

t (ms)

t (ms)0

VL (v)

0

VL (v)t (ms)



R- Load at =900

R- Load at =1350

t (ms)0

VL (v) RL- Load at =450

0

VL (v)

t (ms)

RL- Load at =900

80

15.6PROCEDURE:


angle potentiometer and by operating ON/OFF switch their phase sequence. Make sure the






firing circuit.



TABULAR FORMS.


transformer.



FORMULAE USED:

Average output voltage – R load, VAvg=

cos1

Vm

Average output voltage – RL load, VAvg=

cos

Vm2

81

15.7TABULAR FORMS:

a. For R load


angle ()

Output voltage

(V)

Theoretical

Output

voltage (V)

P

N

1, 230V, 50Hz, AC

230V

0V 0V

30V

K1 K3

A1 A3

G1 G3

T1 T3

4TYN616

RLOAD150, 5A

SINGLE PHASE FULL CONTROLLED BRIDGE CONVERTER WITH R LOAD

K4 K2

A4 A2

G4G2

T4 T2

82

b. For RL load without freewheeling diode:


angle ()

Output voltage

(V)

Theoretical

Output

voltage (V)


P

N

1, 230V, 50Hz, AC

230V

0V 0V

30V

K1 K3

A1 A3

G1 G3

T1 T3

4TYN616

R

L

LOAD150, 5A

0-150mH, 5A

SINGLE PHASE FULL CONTROLLED BRIDGE CONVERTER WITH RL LOAD

K4 K2

A4 A2

G4G2

T4 T2

83

15.9RESULT:

Thus the single phase Full controlled bridge converter with R and RL load is studied and

also plotted the waveforms of different firing angles.


1. State the type of commutation used in this circuit?


3. What are the performance parameters of rectifier?


5. What is the difference between half wave and full wave rectifier?



2. What is Dc output voltage of single phase full wave controller?

3. What are the effects of source inductance on the output voltage of a rectifier?

4. What is commutation angle of a rectifier?


84

Exp. No.:16 Date:

OPERATION OF MOSFET BASED CHOPPER.

16.1OBJECTIVE:

To study the Step up & Step down MOSFET based choppers and draw its output response

graph.

16.2 RESOURCES:

S.NO ITEM RANGE QUANTITY

1Step up & Step down MOSFET

based chopper kit

- 1

2 CRO 20 MHZ 1

3 Patch chords - 15

16.3 MODEL GRAPH (STEP UP CHOPPER) :

MODEL GRAPH (STEP DOWN CHOPPER) :

85

16.4PROCEDURE (STEP UP CHOPPER & STEP DOWN CHOPPER) :

1. Initially keep all the switches in the OFF position

2. Initially keep duty cycle POT in minimum position

3. Connect banana connector 24V DC source to 24V DC imput.

4. Connect the driver pulse [output to MOSFET input

5. Switch on the main supply

6. Check the test point waveforms with respect to ground.

7. Vary the duty cyle POT and tabulate the Ton, Toff & output voltage

8. Trace the waveforms of Vo Vs & Io

9. Draw the graph for Vo Vs Duty cycle, K

16.5 CIRCUIT DIAGRAM (STEP UP CHOPPER) :

16.6 CIRCUIT DIAGRAM (STEP DOWN CHOPPER):

86

16.7 TABULAR FORMS (STEP UP CHOPPER):

Vs = ____________ V

S.NO T ON

(sec)

TOFF

(sec)

T

(sec)

Duty Ratio, k=TON / T Vo=kVs(V)

TABULAR FORMS (STEP DOWN CHOPPER):

Vs = ____________ V

S.NO T ON

(sec)

TOFF

(sec)

T

(sec)

Duty Ratio, k=TON / T Vo=kVs(V)

16.8RESULT:

Thus the output response of Step down & Step up MOSFET based choppers was drawn.


1. What is control methods used in f chopper?2. What is meant by step-up and step-down chopper? 3. Power MOSFET is a voltage controlled device. Why?4. What are the different types of power MOSFET?


1. What is meant by step-up and step-down chopper?


3. What are the advantages of MOSFET’s over BJT’s?

87

Exp. No.:17 Date:

SINGLE PHASE DUAL CONVERTER WITH RL LOAD

17.1OBJECTIVE:

To study and observer the operation of single phase dual converter with RL loads.

17.2RESOURCES:


1

1 dual converter

power and firing

module

- - 1





17.3SPECIFICATIONS:




4. Diode : 25A, 1200V, BY126/BY127


6. Fuses : 16A HRC.

17.4 PRECAUTIONS:








88

17.5 MODEL GRAPH:

NON CIRCULATING CURRENT MODE:

P-TYPE CONVERTER AND N TYPE CONVERTER:

CIRCULATING CURRENT MODE:

N TYPE CONVERTER P TYPE CONVERTER

17.6 PROCEDURE:

1. Switch ON the single phase dual converter firing circuit. Make sure all the pulses are proper

before connecting to the power circuit.

2. Make the connections as per the circuit diagram for non circulating current mode.




firing circuit.



tabular forms.

8. Repeat the same for different input voltage up to max. Voltage as provided in the isolation

transformer.


10. Repeat the same step for circulating current mode also.

89

17.7 Circuit diagram:

Non circulating current mode:

Circulating current mode:

17.8 TABULAR FORMS:

For non circulating current mode


angle ()

Output voltage

(V)

Ton +Toff

(sec)

For circulating current mode:


angle ()

Output voltage

(V)

Ton +Toff

(sec)

90

17.9RESULT:

Thus the single phase dual converter with RL for circulating and non circulating mode of

current was studied and also plotted the waveforms of different firing angles.


1. What is the four quadrant operation?


3. What are modes of operation carried out in dual converter?

4. What are the advantages of dual converter?



2. How to change the circulating to non circulating current mode?

3. Write advantages of dual converter?

4. What are the drawbacks of the dual converter?

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