Power Electronics lab manual BE EEE

EE1303-Power Electronics Lab Manual

MUTHAYAMMAL ENGINEERING COLLEGE, RASIPURAM
Department of Electrical and Electronics Engineering

V Semester – BE (EEE)

EE 1303 - Power Electronics Laboratory

Manual

Prepared by Approved by
Prof.M.Muruganandam, M.E.,(Ph.D), Dr P.Murugesan,B.E.,Ph.D.,
AP/ EEE Proff. & HOD/EEE

Revision No.:1 Date:24.06.2008

Muthayammal Engineering college, Rasipuram. 1


INSTRUCTIONS TO THE CANDIDATE

SAFETY:
You are doing experiments in Power Electronics lab with high voltage and
high current electric power. It may cause even a fatal or loss of energy of your
body system. To avoid this please keep in mind the followings

In case of any wrong observations, you have to SWITCH OFF the power
supply related with it.
You have to tuck in your shirts or wear an overcoat.
You have to wear shoes compulsorily and stand on mats made by
insulating materials to electrically isolate your body from the earth.

ATTENDANCE:
If you absent for a lab class then you have lost several things to learn.
Laboratory should be treated as temple, which will decide your life. So don’t fail
to make your presence with your record notebook having completed
experiments, observation with completed experiments, day’s experiment
particulars with required knowledge about it and stationeries.

MAKING CONNECTIONS:
Get circuit diagram approval from your staff in charge.
Go to the respective worktable and start to give connection as per the
circuit diagram from source side.
Make series circuit connections before the parallel circuits like voltmeter
connections.
Before switch on the power, get circuit connection approval from the staff
in charge.

DOING EXPERIMENT:
Start the experiment in the presence of an instructor / staff in-charge and
do the same by proper procedure.
If staff permits you then precede your experiment.

OBSERVATION:
Before take the wave forms calibrate the CRO.
Note all the required readings in their respective tables.
Note all the wave forms from the CRO.

CALCULATION:
Calculate the required quantities by suitable formulae and tabulate them
with units.
Draw the necessary graphs and write the result with reference.
Get verification of observation and calculation from your staff in charge.

RECORD:


Shows the performance of equipment and yourself. It will be very useful
for future reference. So keep it as follows.
Write neatly; as they have to be preserved enter the readings in the record
notebook those have been written in your observation.
Units should be written for all quantities.
Draw necessary graphs and complete the record before coming to the
next lab class.
Don’t forget to write the theory with precaution and inference of each
experiment.

MAY I HELP YOU

1. Device ratings should be noted.
2. Moving coil meters should be used for DC measurements.
3. Moving iron meters should be used for AC measurements.
4. Use isolated supply for the CRO.
5. Use attenuation probe for high voltage measurements in CRO.



CONTENTS

Sl.No. Name of the experiment Page No.

1. VI CHARACTERISTICS OF SCR 2

2. VI CHARACTERISTICS OF TRIAC 8

3. VI CHARACTERISTICS OF MOSFET 14

4. VI CHARACTERISTICS OF IGBT 20

5. TRANSIENT CHARACTERISTICS OF MOSFET AND SCR 24

6. SINGLE PHASE AC TO DC FULLY CONTROLLED CONVERTER 30

7. SINGLE PHASE AC TO DC HALF CONTROLLED CONVERTER 36

8. STEP DOWN MOSFET BASED CHOPPER 42

9. STEP UP MOSFET BASED CHOPPER 46

10. IGBT BASED SINGLE PHASE PWM INVERTER 50

SERIES RESONANT DC-DC CONVERTER
11. 56
(ZERO CURRENT SWITCHING)

PARALLEL RESONANT DC-DC CONVERTER
12. 60
(ZERO VOLTAGE SWITCHING)



VI CHARACTERISTICS OF SCR

CIRCUIT DIAGRAM:

VI Characteristics

1 Half wave Rectifier

Triggering Circuit for 1 Half wave Rectifier




AIM:
(i) To Conduct an experiment and obtain the anode forward conduction
characteristics of the given SCR also find the latching and holding currents of the given
SCR.
(ii) To Demonstrate how a single-phase half wave rectifier circuit can be
implemented using a given SCR, AC power source and RC firing circuit.

APPARATUS REQUIRED:
S.No. Name of the item Type Range Quantity
1 SCR module TYN612 600V,12A 1
2 Ammeter MC (0-100) mA 1
4 Voltmeter MC (0-30) V 1
5 Digital Multimeter - - 1
6 RC Firing Module - - 1
7 Rheostat - 220 1
8 CRO - - 1
9 CRO probe - - 1
10 Patch Cards - - 10

FORMULA USED:
Vm
1. Average dc output voltage Vdc is Vdc = (1 + cos )
1
V 1 sin 2 2
2. RMS output voltage is Vrms Vrms = m +
2 2
2
Vdc
3. Rectification efficiency % = 2
Vrms
V
4. Form factor FF = rms
Vdc
5. Peak inverse voltage PIV = Vm
6. Ripple factor RF = FF 2 1
1
1 sin 2 2
7. Power factor PF = +
2 2
Where
Vm = maximum or peak voltage in volts = 2Vs
Vs = Supply voltage in volts
= Firing angle
= Extinction angle
= Conduction angle = -



MODEL GRAPH:


1 HALF WAVE RECTIFIER



PRECAUTION:

1. The initial set gate current should be taken as minimum in order to take the
consecutive readings.

2. Maximum anode current, anode-cathode voltage and gate current limit is 600mA,
30V and 20mA respectively

3. Before setting each gate current, keep the Anode to cathode voltage (VAK) as
zero.

PROCEDURE:

VI Characteristics:
1. Connections are made as per the circuit diagram.
2. Switch on the 230V AC supply through three-pin power chord.
3. Keep the gate current (IG) to a suitable value (say minimum of 4 mA to 5mA)
4. Now slowly increase the anode-cathode voltage (VAK) by varying the pot till
thyristor get turned on, with the indication that anode cathode voltage decreases
to it on state voltage drop (i.e 0.7V) and the anode current increases.
5. Note the values of voltmeter (VAK) which is the break over voltage and the
ammeter (I L) which is the latching current value.
6. Further, increase the anode current in steps by varying the anode-cathode
voltage and note the readings.
7. Now reduces the anode cathode voltage (VAK) till the thyristor turned off and find
the holding current.
8. For various gate current take the readings and tabulate it.
9. Finally, a graph of anode current Vs anode-cathode voltage is plotted for various
gate current.



TABULATION:

VI Characteristics:

IG1 = IG2 = IG3 =
S.No.
VAK(V) IA(mA) VAK(V) IA(mA) VAK(V) IA(mA)
1

2

3

4

5

6

1 HALF WAVE RECTIFIER:

Firing Practical Practical Theoretical Theoretical
S.NO.
angle ° Vavg (V) Iavg (A) Vavg (V) Vrms
1

2

3

4

5

6



1 HALF WAVE RECTIFIER:

2. Switch on the triggering circuit
3. Switch on the 24V AC supply
4. By varying potentiometer, vary the firing angle of the converter in order to vary
the output voltage step by step.
5. For each step note down the firing angle, output voltage and load current.
6. The output voltage is theoretically calculated for each step and the readings are
tabulated.

INFERENCE:

DISCUSSION QUESTIONS:

1. What is power electronics?
2. What are the types of converter in power electronics?
3. What is latching and holding current?
4. What is break over voltage?
5. What is forward bias and reverse bias?
6. What is firing angle?
7. Why the negative voltage is not possible in semi converter?
8. What is freewheeling diode?

RESULT:



VI CHARACTERISTICS OF TRIAC

CIRCUIT DIAGRAM:

VI Characteristics

Single-phase A.C phase controller for illumination control




AIM:

(i) To obtain the forward and reverse conduction characteristics of the given
TRIAC also find the latching and holding currents of the given TRIAC.

(ii) To demonstrate how a single- phase AC phase controller can be implemented
for controlling the illumination of lamp, using given TRIAC and RC triggering circuit and
draw the voltage wave form across the lamp.

APPARATUS REQUIRED:

1 TRIAC module BTA 12 600V,12A 1
5 Voltmeter MI (0-300)V 1
6 Ammeter MI (0-500)mA 1
7 Digital Multimeter - - 1
8 Transformer - 230/12V 1
9 CRO - - 1
10 CRO Probe - - 1

FORMULA USED:
1
1 Sin2 2
The RMS output voltage is V0 RMS = Vs +
2
Where
= Firing angle
Vs = Source voltage

PRECAUTION:

1. The initial set gate current should be taken as the value, for gate current for the

2. Maximum triac current, voltage across the triac and gate current limit is 600mA,
30V and 20mA respectively.

3. To see the phase controlled converter output waveform, use a 230 / 12 V
transformer for isolation purpose.



MODEL GRAPH:





PROCEDURE:

VI Characteristics:

1. Connections are made as per the circuit diagram with MT1 +Ve with respect to
MT2.
3. Keep the gate current (IG) to a suitable value (say minimum of 4 mA to 5mA)
4. Now slowly increase the anode-cathode voltage (VAK) by varying the pot till Triac
get turned on, with the indication that anode cathode voltage decreases to it’s on
state voltage drop (i.e 0.7V) and the anode current increases.
5. Note the values of voltmeter (VAK) which is the break over voltage and the
ammeter (I L) which is the latching current value.
6. Further, increase the anode current in steps by varying the anode-cathode
voltage and note the readings.
7. Now reduces the anode cathode voltage (VAK) till the triac turned off and find the
holding current.
8. For various gate current take the readings and tabulate it.
9. Connect MT2 terminal of Triac is + Ve with respect to MT1
10. Repeat the same procedure from 2 to 8
11. Finally, a graph of anode current Vs anode-cathode voltage is plotted for various
gate current for forward and reverse biases.


2. Switch on the 230 V, 50 Hz AC supply
3. By varying potentiometer, vary the firing angle of the converter in order to vary
the output voltage there by the illumination of the lamp will be varied.
4. For each step note down the firing angle, ammeter reading, voltmeter reading
and the output voltage waveform from and tabulate it.
5. Finally, the output voltage waveform is plotted and the theoretical RMS voltage is
calculated.



TABULATION:

VI Characteristics:

MT1 is + Ve with respect to MT2

IG1 = IG2 = IG3 =
S.No.
1

2

3

4

5

MT2 is + Ve with respect to MT1

IG1 = IG2 = IG3 =
S.No.
1

2

3

4

5

Single-phase A.C phase controller

S.No. Firing angle ( ) in I0RMS Measured V0RMS Measured V0RMS Calculated
degree in Amps in Volts in Volts
1
2
3
4
5



INFERENCE:


1. What is bidirectional device?
2. What is bipolar device?
3. What are the applications of phase controlled converter in home appliances?
4. What is the number and range of given triac?
5. What type of firing is used here?
6. How do you change the firing angle?
7. Draw the symbol of Triac.

RESULT:



VI CHARACTERISTICS OF MOSFET

CIRCUIT DIAGRAM:

VI CHARACTERISTICS



VI CHARACTERISTICS OF MOSFET

AIM:
(i) Obtain the steady – state output – side characteristics and transfer
characteristics of the given MOSFET, for a specified value of gate – source
voltage.

(ii) Identify whether given switch is MOSFET or IGBT by finding the
output– side characteristics.

APPARATUS REQUIRED:

1 MOSFET module IRF 840 600V,5A 1
3 Voltmeter MC (0-10)V 1
5 CRO - - 1
6 CRO Probe - - 1

FORMULA USED:

ID
1. Trans conductance Gm = mho
VDS
V DS
2. Output resistance RDS = ohm
ID
Where:
ID = Change in drain current.
VDS = Change in drain to source voltage

PRECAUTION:

The initial set gate voltage should be taken as minimum in order to take the

PROCEDURE:

DRAIN CHARACTERISTICS

1. Connections are made as per the circuit diagram



MODEL GRAPH:


TRANSFER CHARACTERISTICS



3. Keep the gate - source voltage (VGS) to a suitable value (say minimum of 6V to
7V)
4. Now slowly increase the drain-source voltage (VDS) by varying the pot till
MOSFET get turned on, with the indication that drain-source voltage decreases
to it on state voltage drop.
5. Note down the values of drain-source voltage (VDS) and the drain current (I D)
6. For various gate-source voltage take the different set of readings and tabulate it.
7. Finally, a graph of drain-source voltage (VDS) Vs drain current (ID) is plotted for
various gate-source voltage.

TRANSFER CHARACTERISTICS

3. Keep the Drain - source voltage (VDS) to a suitable value
4. Now slowly increase the gate - source voltage (VGS) by varying the pot till
MOSFET get turned on, with the indication that drain current getting constant
value.
5. Note down the values of gate-source voltage (VGS) and the drain current (I D)
6. Finally, a graph of gate - source voltage (VGS) Vs drain current (ID) is plotted.



TABULATION:

Drain Characteristics:

VGS1 = VGS2 = VGS3 =
S.No.
VDS(V) ID(mA) VDS(V) ID(mA) VDS(V) ID(mA)
1

2

3

4

5

Transfer Characteristics:
VDS =

VGS(V)
S.No. ID(mA)
1

2

3

4

5



INFERENCE:


1. What is current control device?
2. What is voltage control device?
3. What is the number and range of given MOSFET?
4. Draw the symbol of MOSFET?
5. What is Transconductance?
6. How to find the output resistance?

RESULT:



VI CHARACTERISTICS OF IGBT

CIRCUIT DIAGRAM:

VI CHARACTERISTICS

MODEL GRAPH:



VI CHARACTERISTICS OF IGBT

AIM:
(i) Obtain the steady – state output – side characteristics and transfer
characteristics of the given IGBT, for a specified value of gate – source voltage.

(ii) Identify whether given switch is MOSFET or IGBT by finding the
output– side characteristics.

APPARATUS REQUIRED:

1 IGBT module IRGBC 600V,10A 1
3 Voltmeter MC (0-10)V 1
5 CRO - - 1
6 CRO Probe - - 1

FORMULA USED:

IC
1. Trans conductance Gm = mho
VCE
VCE
2. Output resistance RCE = ohm
IC
Where:
IC = Change in collector current.
VCE = Change in collector to emitter voltage

PRECAUTION:

The initial set gate voltage should be taken as minimum in order to take the

PROCEDURE:


3. Keep the gate - emitter voltage (VGE) to a suitable value (say minimum of 6V to
7V)



TABULATION:

VGE1 = VGE2 = VGE3 =
S.No.
VCE(V) IC(mA) VCE(V) IC(mA) VCE(V) IC(mA)
1

2

3

4

5



4. Now slowly increase the drain-source voltage (VDS) by varying the pot till
MOSFET get turned on, with the indication that drain-source voltage decreases
to it on state voltage drop.
5. Note down the values of drain-source voltage (VDS) and the drain current (I D)
6. For various gate-source voltage take the different set of readings and tabulate it.
7. Finally, a graph of drain-source voltage (VDS) Vs drain current (ID) is plotted for
various gate-source voltage.

INFERENCE:


1. What is current control device?
2. What is voltage control device?
3. What is the number and range of given IGBT?
4. Draw the symbol of IGBT?
5. What are differences between Transistor, MOSFET and IGBT?
6. How to find the given device is whether MOSFET or IGBT?

RESULT:



TRANSIENT CHARACTERISTICS OF MOSFET AND SCR

CIRCUIT DIAGRAM:

FOR MOSFET

MATLAB CIRCUIT FOR MOSFET



TRANSIENT CHARACTERISTICS OF MOSFET AND SCR

AIM:
(i) Obtain and explain both turning ‘ON’ and turn ‘OFF’ characteristics of
given SCR
(ii) Obtain and explain both turning ‘ON’ and turn ‘OFF’ characteristics of
given MOSFET.

APPARATUS REQUIRED:

S.No. Blocks Type Items Quantity
1 Simulink
i. Sink Scope 1
ii. Source Pulse Generator 1
2 Sim power system
MC Ammeter 1
i. Measurements
MC Voltmeter 1
ii. Elements - RLC series branch 1
- MOSFET 1
iii. Power electronics
- SCR 1
iV. Electrical source - DC source 1

PROCEDURE:

FOR MOSFET

1. Open MATLAB and open Simulink then create a new file (new module)
2. Connections are made as per the circuit diagram by taking the required items
from the corresponding blocks.
3. According to the MOSFET, we should give the block parameter for MOSFET,
RLC series branch, pulse generator and the scope.
4. Now simulate the circuit. The graph of Gate pulse, Drain current and drain to
source voltage can be shown.
5. Finally the print out of the MATLAB circuit and the output is taken.



FOR SCR

MATLAB CIRCUIT FOR SCR



FOR SCR

1. Open MATLAB and open Simulink then create a new file (new module)
2. Connections are made as per the circuit diagram by taking the required items
from the corresponding blocks.
3. According to the SCR, we should give the block parameter for SCR, RLC series
branch, pulse generator and the scope.
4. Now simulate the circuit. The graph of Gate pulse, Anode current and anode to
cathode voltage can be shown.
5. Finally the print out of the MATLAB circuit and the output is taken.



MODEL GRAPH:

FOR MOSFET

FOR SCR



INFERENCE:


1. What is MATLAB?
2. What is a transient characteristic?
3. What is commutation?
4. Where the natural commutation is not possible in SCR?
5. What is the function of scope in MATLAB?

RESULT:



SINGLE PHASE AC TO DC FULLY CONTROLLED CONVERTER

CIRCUIT DIAGRAM FOR R LOAD

Model graph for R Load
°
( = 30°, R=100 )



SINGLE PHASE AC TO DC FULLY CONTROLLED CONVERTER
AIM:
(i) To study the operation of single phase fully controlled bridge converter with R
and R-L loads for continuous and discontinuous conduction modes.
(ii) Also find the performance parameters (Rectification efficiency, form factor,
peak inverse voltage and ripple factor)

APPARATUS REQUIRED:

1 1 SCR bridge module TYN612 600V,12A 1
2 SCR Triggering Kit - - 1
5 CRO - - 1
6 CRO Brobe - - 1

FORMULA USED:

For R load
Vm
1. Average dc output voltage Vdc is Vdc = (1 + cos )
1
1 sin 2 2
2. RMS output voltage is Vrms Vrms = Vm +
2 2

For R-L load continuous conduction:
2Vm
1. Average dc output voltage Vdc is Vdc = cos

Vm
2. RMS output voltage Vrms is Vrms = = Vs
2
For RL load discontinuous conduction:
Vm
3. Average dc output voltage Vdc is Vdc = (cos cos )
1
V2 sin 2 sin 2 2
4. RMS output voltage Vrms is Vrms = m +
2 2 2



CIRCUIT DIAGRAM FOR R-L LOAD

Model graph for R-L Load with continuous conduction
°
( = 30°, R=100 , L=200mH)

Model graph for R-L Load with discontinuous conduction
°
( = 90°, R=100 , L=200mH)



General Formula:
2
Vdc
Vrms
V
Vdc

Where
= Firing angle
= Extinction angle

Procedure:

1. Connections are made as per the circuit diagram for R load
2. Switch on the triggering kit
3. Switch on the 230 V AC supply
4. Switch on the debounce logic
5. By varying potentiometer vary the firing angle of the converter in order to vary the
output voltage step by step.
tabulated.
8. Repeat the same procedure for RL load.



Tabulation for R load:

Vs= R=

S.No. Firing Angle Idc Measured Vdc Measured Vdc Calculated Vrms Calculated
in degree in milliamps in volts in volts in volts

Tabulation for RL load:
Vs= R= L= =

Continuous conduction

Discontinuous conduction



INFERENCE:


1. What is inversion mode of operation?
2. When we connect a freewheeling diode in full converter, what will be the output?
3. Why the inversion mode is not possible in semi converter?
4. Why the power factor of full converter is lower than semi converter?
5. What is , , and µ?

RESULT:



SINGLE PHASE AC TO DC HALF CONTROLLED CONVERTER

CIRCUIT DIAGRAM FOR R LOAD

Model graph for R Load
°
( = 30°, R=100 )



SINGLE PHASE AC TO DC HALF CONTROLLED CONVERTER

AIM:
(i) To study the operation of single phase semi converter with R and R-L loads for
continuous and discontinuous conduction modes.
(ii) Also find the performance parameters (Rectification efficiency, form factor,
peak inverse voltage and ripple factor)

APPARATUS REQUIRED:

1 SCR module with protection TYN612 600V,12A 2
2 Diode module with protection BY126 - 3
3 SCR Triggering Kit - - 1
4 Battery - 12V 1
7 CRO - - 1
8 CRO Brobe - - 1

FORMULA USED:

For R and RL load continuous & discontinuous conduction:
V
1. Average dc output voltage Vdc is Vdc = m (1 + cos )
1
1 sin 2 2
2. RMS output voltage is Vrms Vrms = Vm +
2 2
General Formula:
2
Vdc
Vrms
V
Vdc

Where
= Firing angle
= Extinction angle



CIRCUIT DIAGRAM FOR R-L LOAD

Model graph for R-L Load with continuous conduction
°
( = 30°, R=100 , L=100mH)

Model graph for R-L Load with discontinuous conduction
°
( = 90°, R=100 , L=100mH)



Procedure:

1. Connections are made as per the circuit diagram for RL load
2. Switch on the triggering kit
3. Switch on the 230V AC supply
5. By varying potentiometer vary the firing angle of the converter in order to vary the
output voltage step by step.
tabulated.
8. Repeat the same procedure for RL load.



Tabulation for R load:

Vs= R=


Tabulation for RL load:

Continuous conduction

Discontinuous conduction



INFERENCE:


1. What is power electronics?
2. What are the types of converter in power electronics?
3. What is firing angle?
4. What is active load?
5. Why the negative voltage is not possible in semi converter?
6. What is freewheeling diode?
7. Is a separate freewheeling diode necessary for semi converter? Justify your answer.

RESULT:



STEP DOWN MOSFET BASED CHOPPER

CIRCUIT DIAGRAM

MODEL GRAPH



STEP DOWN MOSFET BASED CHOPPER
AIM:
To study the waveform for MOSFET based step down chopper for different load
for continuous and discontinuous conduction modes.

APPARATUS REQUIRED:

1 MOSFET Module IRF 840 - 1
2 Ammeter MC (0-500mA) 1
3 Voltmeter MC (0-30V) 1
4 Rheostat - - 1
5 RPS - (0-30V) 1
6 CRO - - 1
7 CRO Probe - - 1
8 Patch cards - - -

FORMULA USED:

1. Average dc output voltage Vdc is Vdc = Vs
2. RMS output voltage Vrms is Vrms = Vs

Where:
TON
= Duty cycle of the chopper =
T
TON = on time
T = Total time

Procedure:

2. Switch on the RPS and turn on triggering kit
4. By changing the width of the pulse, obtain the different set of reading.
5. For each step note down the duty cycle, output voltage and load current and
tabulate it.
6. The output voltage is theoretically calculated.
7. Draw the graph as per the reading in the table.



TABULATION:
Vs= T=

S.No. TON TON Idc (Avg) Vdc (Avg) Vdc (Avg)
in ms = Measured Measured Calculated
T
in mA in volts in volts
Vdc = Vs
1
2
3
4
5



INFERENCE:


1. What is chopper and what are the devices generally used for chopper?
2. What are the types of chopper?
3. What is step down chopper?
4. What are the control strategies used for choppers?
5. Why frequency modulation is not preferred mostly?
6. Why thyristor is not preferred in chopper circuit mostly?

RESULT:



STEP UP MOSFET BASED CHOPPER

CIRCUIT DIAGRAM:

Model graph for step up operation



STEP UP MOSFET BASED CHOPPER

AIM:
To study the waveform for MOSFET based step up chopper for different load for
continuous and discontinuous conduction modes.

APPARATUS REQUIRED:

1 MOSFET Module IRF 840 - 1
2 Ammeter MC (0-500mA) 1
3 Voltmeter MC (0-30V) 1
4 Rheostat - - 1
5 RPS - (0-30V) 1
6 Diode Py 127 - 1
7 Inductor Ferrite core 100mH 1
8 CRO - - 1
9 CRO Probe - - 1
10 Patch cards - - -

FORMULA USED:

Vs
Average dc output voltage Vdc is Vdc =
(1 )
Where:
TON
= Duty cycle of the chopper =
T
TON = on time
T = Total time

PROCEDURE:

2. Switch on the RPS and turn on triggering kit
4. By changing the width of the pulse, obtain the different set of reading.
5. For each step note down the duty cycle, output voltage and load current and
tabulate it.
6. The output voltage is theoretically calculated for each step.
7. Draw the graph as per the reading in the table.



TABULATION:
Vs= T=

S.No. TON TON Idc (Avg) Vdc (Avg) Vdc (Avg)
in ms = Measured Measured Calculated
T
in mA in volts in volts
Vs
Vdc =
(1 )
1
2
3
4
5



INFERENCE:


1. What is chopper and what are the devices generally used for chopper?
2. What are the types of chopper?
3. What is step up chopper?
4. What are the control strategies used for choppers?
5. Why frequency modulation is not preferred mostly?
6. Why thyristor is not preferred in chopper circuit mostly?

RESULT:



IGBT BASED SINGLE PHASE PWM INVERTER

CIRCUIT DIAGRAM



IGBT BASED SINGLE PHASE PWM INVERTER

AIM:
To study the operation of single-phase bridge inverter with sinusoidal pulse width
modulation with R load.

APPARATUS REQUIRED:

1 IGBT Module - - 1
2 Inverter control module - - 1
3 CRO - - 1
4 Ammeter MI (0-5A) 1
5 Voltmeter MI (0-300V) 1
6 Patch cards - - -

FORMULA USED:

1. Modulation index (m) is m = Ar / Ac

2. Output voltage V0 = m Vs

Where
Ar = Amplitude of reference signal
Ac = Amplitude of carrier signal
Vs = Source voltage



Model graph

Sinusoidal Pulse width modulation

Voltage and current waveforms



Precaution:

1. Check whether AC main switch is off condition in both the trainer.
2. Check whether control module mode selector switch is in first position (Sine
wave).
3. Check whether control module pulse release switch SW4 in control module is off
position.
4. Check whether 24V AC switch is in off position.
Procedure:
1. Make the connection as per the circuit diagram.
2. Switch on the AC main in both the trainer.
3. Measure the amplitude and frequency of sine wave and carrier triangular wave
and tabulate it. Also adjust sine wave frequency to 50Hz.
4. Connect CRO probe to observe the load voltage and load current waveform.
5. Release the switch SW4 in the inverter control module and switch SW1 in the
IGBT power module.
6. Measure the output voltage.
7. Using the amplitude POT to vary step by step, for each step note down the
amplitude and frequency of sine wave and triangular waveform and also
measure the output voltage and tabulate it.
8. Then find the theoretical output voltage by using the formula.



Tabulation:

Vs=

S.No. Amplitude Amplitude Modulation I0 V0 V0
of carrier of index Measured Measured Calculated
triangular reference m= Ar/Ac in Amps in Volts in Volts
wave sine wave V0 = m X V s
(Ac) in (Ar) in
volts volts
1
2
3
4
5
6



INFERENCE:


1. What is inverter?
2. Why we go for PWM?
3. What are the different types of PWM?
4. What is modulation index and what are the types?
5. What are the advantages of IGBT?

RESULT:




CIRCUIT DIAGRAM:

MODEL GRAPH:




AIM:

To determine the voltage and current wave form of series resonant dc-dc
converter (Zero current switching).

APPARATUS REQUIRED:

1 Resonant converter module VPET-315 - 1
2 Ammeter MC (0-2) A 1
4 CRO - - 1
5 CRO Brobe - - 1

FORMULA USED:
1
Frequency f = Hz
T
Where:

T= Time
f = Frequency

PRECAUTIONS:

Initially keep the frequency adjustment POT in minimum position

PROCEDURE:

2. Initially keep frequency adjustment POT in minimum position.
3. Switch on the main supply
4. Connect the “P” Pin connector from PWM output and PWM input
5. Connect the banana connector P10 to P4 , P8 to P11
6. Connect the current sensing resistor (1 / 20 W) across the banana connector P2
to P3.
7. The voltmeter is connected across P5 and P12



TABULATION:

Switching
Output Output
S.No. Time (ms) Frequency
Voltage (V) Current (A)
(KHz)
1

2

3

4

5



8. Connected the R load across P5 and P12 through ammeter.
9. Adjust the frequency POT and set switching frequency 40KHz.
10. Connect the CRO across the connector T1 (+) and ground. Another channel is
connected to P2 (+), P3 (-)
11. Now observe the switch voltage and current wave.
12. Similarly observe the switch voltage and current waveform for various switching
frequency.

INFERENCE:


1. What is resonance?
2. What is the condition for resonance?
3. What are the advantages of resonant converter?
4. What is soft switching?
5. What types of resonant converter?
6. What is zero current switching?
7. What is zero voltage switching?

RESULT:




CIRCUIT DIAGRAM:

MODEL GRAPH:




AIM:

To determine the voltage and current wave form of parallel resonant dc-dc
converter (Zero voltage switching).

APPARATUS REQUIRED:

1 Resonant converter module VPET-315 - 1
2 Ammeter MC (0-2) A 1
4 CRO - - 1
5 CRO Brobe - - 1

FORMULA USED:
1
Frequency f = Hz
T
Where:

T= Time
f = Frequency

PRECAUTIONS:

Initially keep the frequency adjustment POT in minimum position

PROCEDURE:

2. Initially keep frequency adjustment POT in minimum position.
3. Switch on the main supply
4. Connect the “9” Pin connector from PWM output and PWM input
5. Connect the banana connector P10 to P4, P8 to P11
6. Connect the current sensing resistor (1 / 20 W) across the banana connector P2
to P3.
7. The voltmeter is connected across P5 and P12



TABULATION:

Switching
Output Output
S.No. Time (ms) Frequency
Voltage (V) Current (A)
(KHz)
1

2

3

4

5



8. Connected the R load across P5 and P12 through ammeter.
9. Adjust the frequency POT and set switching frequency 40KHz.
10. Connect the CRO across the connector T1 (+) and ground. Another channel is
connected to P2 (+), P3 (-)
11. Now observe the switch voltage and current wave.
12. Similarly observe the switch voltage and current waveform for various switching
frequency.

INFERENCE:


1. What is resonance?
2. What is the condition for resonance?
3. What are the advantages of resonant converter?
4. What is soft switching?
5. What types of resonant converter?
6. What is zero current switching?
7. What is zero voltage switching?

RESULT:


Power Electronics lab manual BE EEE

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