POWER ELECTRONICS AND SIMULATION LAB

EEE
B.Tech. III Year II Sem
 POWER ELECTRONICS AND SIMULATION LAB
Any Eight of the Experiments in power electronics lab

1. Study of Characteristics of SCR, MOSFET and IGBT.

2. Gate Firing Circuits for SCR.

3. Single Phase Ac Voltage Controller with R and RL Loads.

4. Single Phase half controlled & Fully Controlled Bridge Converter with R and
RL Loads.

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

6. Single Phase Cyclo-converter with R & RL loads.

7. Single phase series & Parallel inveter with R & RL loads.

8. Single Phase Bridge inverter with R and RL loads

Any Two Simulation Experiments with PSPICE/PSIM.
1. DC Jones chopper with R & RL loads.
2. Three phase half controlled bridge converter with R load.
3. Single phase dual converter with RL loads.
4. (a)Simulation of single-phase Half wave converter using R and RL loads
(b)Simulation of single-phase full converter using R, RL and RLE loads
(c)Simulation of single-phase Semi converter using R, RL and RLE loads
5. (a)Simulation of Single-phase AC voltage controller using R and RL loads
(b)Simulation of Single phase Cyclo-converter with R and RL-loads
6. Simulation of Buck chopper
7. Simulation of single phase Inverter with PWM control
8. Simulation of three phase fully controlled converter with R and RL loads, with
and without freewheeling diode. Observation of waveforms for Continuous and
Discontinuous modes of operation.
9. Study of PWM techniques
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.

 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.

 You must bring the related text book which may deal with the relevant
experiment.

 Get the circuit diagram approved.

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

 Plan well the disposition of the various equipments on the worktable so that the
experiment can be carried out.

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

 For the purpose of speed measurement in rotating machines, keep the

tachometer in the extended shaft. Avoid using the brake drum side.

 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. They will have to repeat the lab course in subsequent
semester after paying prescribed fee.

 Use isolated supply for the measuring instruments like CRO in Power
Electronics Laboratory experiments.
 Exp-1

1a) STUDY OF SCR CHARACTERISTICS

AIM: To study the V-I Characteristics of SCR. Finding the value of Latching current,
Holding current, Gate voltage and gate current.

Apparatus required:

S.No. Name of the equipment Range Qty

01 SCR characteristics Trainer - 01

02 Patch chords - Adequate

Specifications:

S.No. Specifications Range

1 Standard voltage rating of SCR used 500V

2 IRMS(RMS value of current) 5A

3 Fuse 1A

CIRCUIT DIAGRAM:

IA
IG
PROCEDURE:

V-I CHARACTERISTICS:-

1. Make all connections as per the circuit diagram.

2. Initially keep VGS & V2 at minimum position & R2 maximum position.
3. Adjust Gate current Ig to some constant (2.5/5.0mA) by varying the VGS.
4. Now slowly vary V2 and observe Anode to Cathode voltage VAK and Anode
current IA.
5. Tabulate the readings of Anode to Cathode voltage VAK and Anode current IA.
6. Repeat the above procedure for different Gate current Ig.

GATE TRIGGRING AND FINDING VG AND IG:-

1. Keep all positions at minimum.

2. Set Anode to Cathode voltage VAK to some volts say 15V.
3. Now slowly vary the VGS voltage till the SCR triggers and note down the
reading of gate current(IG) and Gate Cathode voltage(VGK) and rise of anode
current IA
4. Repeat the same for different Anode to Cathode voltage and find VAK and IG
values.

TO FIND LATCHING CURRENT:-

1. Keep R2 at middle position.

2. Apply 20V to the Anode to cathode by varying V2
3. Raise the Vg voltage by varying VGS till the device turns ON indicated by
sudden rise in IA . At what current SCR trigger it is the minimum gate current
required to turn ON the SCR.
4. Now set R2 at maximum position, then SCR turns OFF, if it is not turned off
reduce V2 up to turn off the device and put the gate voltage.
5. Now decrease the R2 slowly, to increase the Anode current gradually in steps.
6. At each and every step, put OFF and ON the gate voltage switches VGS. If the
Anode current is greater than the latching current of the device, the device says
ON even after switch OFF S1, otherwise device goes to blocking mode as soon as
the gate switch is put OFF.
7. If IA>IL then, the device remains in ON state and note that anode current as
latching current.
8. Take small steps to get accurate latching current value.
 TO FIND HOLDING CURRENT:-

1. Now increase load current from latching current level by varying R2 & V2
2. Switch OFF the gate voltage switch S1 permanently (now the device is in ON
state)
3. Now increase load resistance(R2), so that anode current reducing, at some
anode current the device goes to turn off .Note that anode current as holding
current.
4. Take small steps to get accurate holding current value.

Observe that IH<IL

TABULAR COLUMN:

IG =….(mA) IG =….(mA)
S.No.
VAK (V) IA (mA) VAK (V) IA (mA)
MODEL GRAPH: Pin configuration

IA
I g1
I g2
SCR
ig2 >ig1

VAK

K A G

Viva questions: -

1. Explain the working operation of VI characteristics of S.C.R.

2. Define Holding current, Latching current on state resistance, Break down
3. voltage
4. Explain the working operation of S.C.R. characteristics by using two
5. transistor analogy
6. Write an expression for anode current
7. Mention the applications of S.C.R.?

RESULT:
 1b) STUDY OF MOSFET CHARACTERISTICS

AIM: To study the Output and Transfer Characteristics of MOSFET.

Apparatus required:

S.No. Name of the equipment Range Qty

01 MOSFET characteristics Trainer - 01

02 Patch chords - Adequate

Specifications:

S.No. Specifications Range

1 Standard voltage rating of MOSFET used 500V

2 IRMS(RMS value of current) 5A

3 Fuse 1A

CIRCUIT DIAGRAM:
PROCEDURE:

TRANSFER CHARACTERISTICS:

1. Make all connections as per the circuit diagram.

2. Initially keep VGS & VDS at minimum position and R2 middle position.
3. Set VDS to some say 10V.
4. Slowly vary Gate source voltage VGG .
5. Note down ID and VGS readings for each step.
6. Repeat above procedure for 20V & 30V of VDS. Draw Graph between ID & VGS.
OUTPUT CHARACTERISTICS:

1. Initially set VGS to some value say 3V by varying VGG.

2. Slowly vary VDD and note down ID and VDS
3. At particular value of VGS there a pinch off voltage between drain and
source.
If VDS< VP device works in the constant resistance region and IO is directly
proportional to VDS. If VDS>VP device works in the constant current region.

4. Repeat above procedure for different values of VGS and draw graph between
ID VS VDS.
TABULAR COLUMN:

OUTPUT CHARACTERISTICS:

VGS = V VGS = V
S.No.
VDS (Volts) I D(mA) VDS (Volts) I D(mA)
TRANSFER CHARACTERISTICS:

VDS= (Volts) VDS= (Volts)

S.No.
VGS (V) I D(mA) VGS (V) I D(mA)

MODEL GRAPH:

Fig: Output Characteristics Fig: Transfer Characteristics

RESULT:
 1c) STUDY OF IGBT CHARACTERISTICS

AIM: To study the Output and Transfer Characteristics of IGBT.

Apparatus required:

S.No. Name of the equipment Range Qty

01 IGBT characteristics Trainer - 01

02 Patch chords - Adequate

Specifications:

S.No. Specifications Range

1 Standard voltage rating of IGBT used 500V

2 IRMS(RMS value of current) 5A

3 Fuse 1A

CIRCUIT DIAGRAM:
PROCEDURE:

TRANSFER CHARACTERISTICS:

1. Make all connections as per the circuit diagram.

2. Initially keep V1 & V2 at minimum position and R2 middle position.
3. Set VCE to some say 10V.
4. Slowly vary Gate Emitter voltage VGE by varying V1.
5. Note down IC and VGE readings for each step.
6. Repeat above procedure for 20V & 25V of VCE. Draw Graph between IC & VGE.

OUTPUT CHARACTERISTICS:

1. Initially set VGE to some value say 5V by varying V1.

2. Slowly vary V2 and note down IC and VCE readings.
3. At particular value of VGE there a pinch off voltage VP between Collector and
Emitter.
If VCE< VP device works in the constant resistance region and IC is directly
proportional to VCE. If VCE>VP device works in the constant current region.

4. Repeat above procedure for different values of VGE and draw graph between
IC VS VCE.
TABULAR COLUMN:

OUTPUT CHARACTERISTICS:

VGE= (Volts) VGE= (Volts)

S.No.
VCE (V) IC(A) VCE (V) IC(A)
TRANSFER CHARACTERISTICS:

VCE = V VCE = V
S.No.
VGE (Volts) IC (Amps) VGE (Volts) IC (Amps)

MODEL GRAPH:

Fig: Collector Characteristics Fig: Transconductance Characteristics

RESULT:
 Exp-2
Gate Firing Circuits for SCR

AIM: To study amplitude control of SCR with R-triggering, RC-triggering, and UJT-
triggering.

Apparatus Required:

S.No. Name of the equipment Range Qty

01 Resistance Firing Circuit KIT - 01

02 Patch chords - Adequate

03 CRO with differential module - 01

04 Digital Multimeter 0-200Ω/2A 01

2a) Resistance Triggering

Circuit Diagram:

VL

D 4K7Ω

12V G
K
10KΩ
Potentiometer
 HALF WAVE TRIGGERING

4K7Ω

FULLWAVE TRIGGERING

PROCEDURE: (R-TRIGGERING)

1. Make the connections as per the circuit diagram and connect the DC voltmeter
or multimeter across the load.
2. Switch on the power supply.
3. Observe the load waveform in the CRO.
4. Gradually vary the potentiometer and note down the firing angle and
corresponding load voltage using multimeter.
5. Switch off the power and remove the connections.
6. Plot a graph of firing angle vs load voltage.
TABULAR COLUMN (Half Wave R-TRIGGERING):

Input Input Output Load voltage

Cycle Firing
S.No. Voltage Cycle Time
On Time angle(α)
(V) (𝑥 sec) (𝑦 sec) Theoretical(vo) Practical

1
2
3

𝑥
Firing angle (α) =[ 180 − × 360 ]
𝑦

O/p voltage Vo = [Vm/2π] (1+cosα) in volts

MODEL GRAPH (Half Wave R-TRIGGERING):

VS

VL
t

VAK

t
TABULAR COLUMN (Full Wave R-TRIGGERING):

Input Input Output Load voltage

Cycle Firing
S.No. Voltage Cycle Time
On Time angle(α)
(V) (𝑥 sec) (𝑦 sec) Theoretical(vo) Practical

1
2
3

𝑥
Firing angle (α) =[ 180 − × 360 ]
𝑦

O/p voltage Vo = [Vm/π] (1+cosα) in volts

MODEL GRAPH (full Wave R-TRIGGERING):

VS

VL
t

VAK

Result:
 2b) RC-Triggering
Circuit diagram:

RC-Half Wave Triggering

RC-Full wave triggering

PROCEDURE (RC-TRIGGERING):

1. Make the connections as per the circuit diagram.

2. Switch on the power supply.
 3. Note down the output waveform across the load using a CRO.
4. Repeat the procedure for various resistor values of potentiometer.
5. Switch off the power and remove the connections.

TABULAR COLUMN (Half Wave RC-TRIGGERING):

Input
Input Output Load voltage
Cycle Cycle Firing
S.No. Voltage
Time On Time angle(α)
(V) (𝑦 sec)
(𝑥 sec) Theoretical(vo) Practical

1
2
3

𝑥
Firing angle (α) =[ 180 − × 360 ]
𝑦

O/p voltage Vo = [Vm/2π] (1+cosα) in volts

MODEL GRAPH (Half Wave RC-TRIGGERING):

TABULAR COLUMN (Full Wave RC-TRIGGERING):

Input Input Output Load voltage

Cycle Firing
S.No. Voltage Cycle Time
On Time angle(α)
(V) (𝑥 sec) (𝑦 sec) Theoretical(vo) Practical

1
2
3

𝑥
Firing angle (α) =[ 180 − × 360 ]
𝑦

O/p voltage Vo = [Vm/π] (1+cosα) in volts

MODEL GRAPH (FULL Wave RC-TRIGGERING):
 2c) UJT Triggering

AIM: To Study Amplitude Control of SCR with UJT Triggering.

APPARATUS:

1. SCR firing circuit module

2. CRO

3. Patch cards

4. Digital Multimeter

CIRCUIT DIAGRAM:

PROCEDURE:
1. Circuit connections are made for UJT triggering circuit

2. Vary the firing angle using potentiometer and note down the load voltage using
multimeter

3. Observe the load voltage waveform on the CRO

4. Trace the graphs of input voltage and voltage across SCR for any one firing angle.

From these two graphs trace the graph for load voltage

5. Plot a graph of firing angle against load voltage

TABULAR FORM:

Input Input Output Load voltage

Cycle Firing
S.No. Voltage Cycle Time
On Time angle(α)
(V) (𝑥 Ms) (𝑦 Ms) Theoretical(vo) Practical

1
2
3

𝑥
Firing angle (α) =[ 180 − × 360 ]
𝑦

O/p voltage Vo = [Vm/2π] (1+cosα) in volts

LOAD VOLTAGE WAVE FORMS:

RESULT:
 Exp-3

SINGLE PHASE AC VOLTAGE CONTROLLER

USING TRIAC

AIM: To study the single phase AC voltage controller and observe the output waveform
with R Load.

Apparatus required:

S.No. Name of the equipment Range Qty

Single phase AC voltage controller

01 - 01
power circuit and firing circuit

02 CRO with deferential module - 01

03 Patch chords and probes - Adequate

04 Isolation Transformer 230/30V, 5A 01

05 Variable Rheostat 0-200Ω / 5A 01

07 AC Voltmeter 0-300V 01

Circuit Diagram:

Procedure:

1. Make all connections as per the circuit diagram.

2. Connect firstly 30V AC supply from Isolation Transformer to circuit.
3. Connect firing pulse from firing circuit to TRIAC as indication in circuit.
4. Connect resistive load 200Ω / 5A to load terminals and switch ON the MCB and IRS
switch and trigger output ON switch.
5. Observe waveforms in CRO, across load by varying firing angle gradually from 1800 -
00 .
6. Measure output voltage by connecting AC voltmeter across load.
7. Tabulate all readings for various firing angles.
8. Observe the various waveforms at different points in circuit by varying the Resistive
Load.
9. Calculate the output voltage theoretically and compare with it practically obtained
values.

TABULAR COLUMN:

Output voltage (VL)

Firing angle in
S.No. Input Voltage (V in)
Degrees
Theoretical Practical

MODEL CALCULATIONS:
V0r = (V / √∏) * [(∏-sin2
 = Firing Angle
V = RMS Value across transformer output

FOR R-LOAD:
Vavg=(Vm/п) (1+cosα)
Vm= α=
FOR RL-LOAD:
Vavg= (Vm/п) (cosα-cosβ)
Where β= п+α
Vm= α=

OUTPUT WAVE FORMS:

RESULT:
 Exp-4

SINGLE PHASE HALF CONTROLLED & FULLY CONTROLLED

BRIDGE CONVERTER

AIM: To study the single phase half controlled & fully controlled bridge converter and to
observe output wave forms with

i) R Load.
ii) R-L load with free wheeling diode.
iii) R-L load without free wheeling diode.

Apparatus Required:

S.No. Name of the equipment Range Qty

01 Single phase Half controlled bridge

- 01
converter power circuit and firing circuit

02 Single phase full controlled bridge converter

- 01
power circuit and firing circuit

03 CRO with deferential module - 01

04 Patch chords and probes - Adequate

05 Isolation Transformer Tapping from 30V to 230V /

01
5A

06 Variable Rheostat 0-100Ω / 2A 01

07 Inductor 100 or 250mH / 5A 01

08 DC Voltmeter 0-300V 01

09 DC Ammeter 0-5A 01

Circuit Diagram(R Load):

Circuit Diagram(R Load):
(0-5A)

(0-300V)
NOTE: IF SCR’S ARE NOT TRIGGERED, INTERCHANGE TERMINALS A AND B.

R-L load without free wheeling diode

(0-5A)

(0-300V)

R-L load with free wheeling diode

(0-5A)
(0-300V)
Procedure:

1. The connections are made as shown in the circuit of fully controlled rectifier with
R-load using isolation transformer.
2. The Gate & the Cathode terminals of four SCR’s are connected to the respective
points on the firing module.
3. Check all connections and confirm connections made are correct before switching
on the equipments.
4. Keep the firing angle knob at 1800 degree (minimum position).switch ON the firing
unit.
5. Now switch ON the power circuit (MCB).
6. The firing angle is varied output waveform is seen on a CRO.
7. The firing angle is varied and DC output voltage and current through the load is
noted.
8. Keep the firing angle knob at 1800 degree (minimum position), switch OFF the
firing unit. Remove the patch cards.
9. Do the experiment for R-L load.

TABULAR COLUMN:

Firing Output voltage (V0) Output Current (I0)

Input Voltage angle in
S.No.
(V in) Degrees Theoretical Practical Theoretical Practical

MODULE CALCULATIONS:

For R-L Load: For R Load:

V0 = (2√2V/∏) * Cosα V0 = (√2V/∏) * (1+Cosα)

I0 = (2√2V/∏R) * Cosα I0 = (√2V /∏R) * (1+Cosα)

α = Firing Angle

V = RMS Value across transformer output

MODEL GRAPHS
 For R-Load and RL- Load with free wheeling diode
α

For RL – Load without free wheeling diode

RESULT:
 EXP-5

FORCED COMMUTATION CIRCUITS

AIM:

To study the module and waveforms of forced commutation circuits.

1. Class A commutation – Self commutation by resonating load

2. Class B commutation – self commutation by IC circuit
3. Class C commutation – Complementary commutation.
4. Class D commutation – Auxiliary commutation.
5. Class E commutation – External commutation.

APPARATUS REQUIRED:

1. Forced commutation unit.

2. Loading Rheostat : 50 Ohms, 2A.
3. Regulated power supply : 0-30VDC, 2A.
4. 20 MHz dual trace oscilloscope with 1:10 BNC probes.

SPECIFICATIONS:

1. Thyristors : TYN 612.

2. Diodes : BYQ 28-200

3. Transistor : TIP 122.

4. Capacitor : C1= 6.8f , 100V C2= 10f , 100V

6. Inductor : L1=250 H, 2A. L2=500 H, 2A.L3 = 1m H.

7. Fuses : 2A Glass fuse

CIRCUIT DIAGRAM:
PROCEDURE:

1. Switch ON the mains supply to the firing circuit. Observe the

trigger outputs in the firing circuit by varying frequency
potentiometer and duty cycle potentiometer. Make sure the firing
pulses are proper before connecting to the power circuit.
2. Check the DC power supply between the DC input points.
3. Check the resistance between anode and cathode of all SCRs.
4. Check the resistance between the Gate and cathode of SCRs.
5. Check the diode and Transistor and their polarities.
6. Check the fuse in series with the DC input.
7. Make sure that all the components are good and firimg pulses are
correct before starting the experiment.
CLASS A&B:

1. Make the connections as per the circuit diagram.

2. Connect the trigger output T1 from the firing circuit to the Gate and
cathode of SCR T1.
3. Switch ON the DC supply and switch ON the trigger pulses by
operating ON/OFF switch in the firing circuit
4. Observe the voltage waveform across load using oscilloscope by
varying the frequency potentiometer. Duty cycle potentiometer is of no
use in this experiment.
5. Repeat the same for different values of R, L and C.
6. Draw the waveforms in the Graph for different R, L and C.
CLASS C:

1. Make the connections as per the circuit diagram.

2. Connect the trigger output T1 &T2 from the firing circuit to the Gate
and cathode of SCR T1 &T2.
3. Switch ON the DC supply and switch ON the trigger pulses by
operating ON/OFF switch in the firing circuit.
4. Observe the voltage waveform across R1, R2 and C using oscilloscope
by varying the frequency and duty cycle potentiometers.
5. Repeat the same for different values of R & C.
6. L is of no use in this circuit.
 7. Draw the waveforms in the graph for different R & C.
CLASS D:

1. Make the connections as per the circuit diagram.

2. Connect the trigger outputs T1 and T2 from the firing circuit to gate
and cathode of SCRs T1 & T2.
3. Initially keep the trigger ON/OFF switch at OFF position to charge the
capacitor. This can be observed by connecting CRO across the
capacitor.
4. Switch ON the DC supply and switch ON the trigger pulses by
operating ON/OFF switch in the firing circuit.
5. Observe and note down the voltage waveform across the load. T1, T2
and C using oscilloscope by varying the frequency and duty cycle
potentiometers.
6. Repeat the same for different values of load. L & C.
CLASS E:

1. Make the connections as per the circuit diagram.

2. Connect V2 supply from an external DC power supply unit.
3. Connect the trigger output T1 from the firing circuit to gate and
cathode of SCR T1.
4. Connect T2 to the transistor base and emitter points.
5. Switch ON the DC supply, external DC supply and the trigger pulses
by operating ON/OFF switch in the firing circuit.
6. Observe and note down the voltage waveform across the load.
7. Repeat the same by varying the frequency and duty cycle
potentiometers.
8. Draw the waveforms in the graph for different frequency and duty
cycle.
PRECAUTIONS:

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

2. Ensure all the controlling knobs in fully counter clock wise 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
respective SCRs in the power circuit.
6. Ensure switch OFF the input supply first and then trigger pulses to
avoid short circuit.

EXPECTED WAVE FORMS:

RESULT:
 EXP-6

SINGLE PHASE CYCLO - CONVERTER

AIM:

To study the module and wave forms of a 1Ф center tapped cyclo - converter with
R and RL loads.

APPARATUS REQUIRED:

1. 1Ф cyclo - converter firing circuit and power circuit units.

2. 1Ф 230 V /230 V -0-230 V center- tapped transformer.

3. 1Ф 230 V / 0-270 V auto transformer.

4. Loading Rheostat: 50 Ohms, 2 A.

5. Loading inductor; 50 mH, 2 A.

6. 20 MHz dual trace oscilloscope with 1:10 BNC probes.

SPECIFICATIONS:

1. Input : 0-230 V 1- Ф AC supply.

2. Load : 15 A

3. Thyristor : 25 A, 1200 V, type 25 RIA 120

4. MCB : two pole 230 V / 16A.

CIRCUIT DIAGRAM:
PROCEDURE:

1. Switch ON the main supply to the firing circuit and power circuit. Observe
the trigger outputs by changing frequency division push buttons and
varying the firing angle control knob. 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 respective SCRs in the
power circuit.

4. Initially connect the input terminals to the 30V- 0 -30V terminals of the
center tapped transformer.

5. Set the frequency division to 2. Switch ON the trigger pulses. And switch ON
the MCB.

6. Vary the firing angle potentiometer and observe the voltage wave forms
across load using oscilloscope.

7. Note down the reading in the tabular column.

8. After ensuring correct output at low voltage, increase the input voltage to
230V-0-230V in steps and note down the corresponding readings.

9. Follow the above procedure for frequency divisions 3 to 9.

10. Draw the wave forms in the graph at firing angles 0o, 45o, 90o, 135oand
180o..

TABULAR COLUMN:

S.NO. Input Frequen Firing Output Output

voltage(V) cy angle voltage current
division (o) (V) (A)
s
PRECAUTIONS:

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

2. Ensure all the controlling knobs in fully counter clock wise position
before starting experiment.
3. Handle everything with care.
4. Change the frequency divisions only when the trigger pulse switches at OFF
position.
5. Make sure the firing pulses are proper before connecting to the power
circuit.
6. If the out put is zero even after all power connections, switch OFF the MCB
and adjust interchange AC input connections to the power circuit. This is to
make the firing circuit and power circuit to synchronize.

EXPECTED WAVE FORMS:

RESULTS:
 EXP-7

SINGLE PHASE SERIES & PARALLEL INVERTER WITH R AND RL

LOADS

AIM: To construct series & parallel inverter and to study its performance.

APPARATUS REQUIRED:

S.no Name of the component Range Quantity

1 Parallel inverter module - 1

2 Parallel inverter module _ 1

3 DC power supply 30v/2A _

4 Load rheostat 100v /10w 1

5 Digital multimeter _ 1

6 CRO _ 1

Patch cards _ As per requirement

SERIES INVERTER CIRCUIT DIAGRAM

PARALLEL INVERTER CIRCUIT DIAGRAM

Series Inverter Procedure:

1. To begin with switch on the power supply to the firing circuit check that Trigger
pulses by varying the frequency.
2. Connections are made as shown in the circuit diagram.
3. Now connect trigger outputs from the firing circuits to gate and cathode of SCRs T1 &
T2.
4. Connect DC input from a 30v/2A regulated power supply and switch on the input DC
supply.
5. Now apply trigger pulses to SCRs and observe voltage waveform across the load.
6. Measure Vrms & frequency of o/p voltage waveform.

Firing Circuit: This part generates two pairs of pulse transformer isolated trigger two
SCR’s connected as series inverter. ON/OFF switch is provided for the trigger pulses
which can be used to switch ON the inverter. Frequency of the inverter can be varied
from 100 Hz to 1 KHz approximately.
Power Circuit: This part consists of two SCR’s two diodes. A center tapped inductor
with tappings and 4 capacitors. Input supply terminals with ON/OFF switch and a fuse
is provided. All the devices in this unit mounted on a proper heat sink, snubber circuit
for dv/dt protection and a fuse in series with each device for short circuit protection.
All the points are brought out to front panel for inter connections. They have to be
interconnected as shown in the circuit diagram. Fly wheeling diodes can be connected
across SCR’s and its effect can be observed.

Model Graph:
PARALLEL INVERTER PROCEDURE:

1) Circuit connections are made as shown in the circuit diagram by connecting

rheostat as load with input dc voltage at 24v.
2) Check all the connections and confirm connections made are correct before
switching on the equipment.
3) Switch on the DC power supply to the inverter and also the inverter circuit.4)
4) Vary the frequency of the inverter circuit in steps, for each step note down the
output voltage.
5) Observe the load voltage waveform on the CRO.
6) Plot a graph of frequency vs. output voltage.
7) Tabulate the observations.
8) A graph of AC voltage Vac Vs. duty cycle.
9) Draw the load voltage waveforms.

TABULAR FORM:

S.NO Time period in(ms) Frequency in Hz Load voltage in volts

FORMULAE:

Capacitor voltage VC =2VS [2exp (-n2tc /4RC)-1]

Circuit turn off time tc = (4RC ln2/n2)

Commutating capacitance C = (n2.tc /4R.ln2)

RESULT:-
 EXP-8

SINGLE PHASE BRIDGE INVERTER

AIM:- To construct a MC-Murray–Bedford inverter and study its performance.

APPARATUS:-

1. MC-Murray-bedford inverter anode with firing circuit

2. DC power supply 30v/2a dual channel

3. Loading rheostat 100E/10w

4. Digital multimeter

5. patch cards

CIRCUIT DIAGRAM:-
PROCEDURE:-

1. Circuit connections are made as shown in the circuit diagram by connecting

rheostat as load with input DC voltage at 15-0-15v
2. Check all the connections and confirm connections made are correct before
switching on the equipment.
3. Switch on the D.C power supply, to the inverter and also inverter circuit.
4. Vary the frequency of the inverter circuit in steps for each step note down the
output voltages.
5. Observe load voltage waveforms in CRO.
6. Tabulate the readings in the table.
7. Draw the load voltage waveform.

TABULAR FORM:

S.NO Time period in(ms) Frequency in Hz Load voltage in volts

NOTE:-

1. For commutation failure, switch off inverter circuit as well as power supply. Again
switch on the inverter circuit as well as power supply for proper commutation
2. At lower frequencies, SCR may not turn on due to insufficient voltages across the
capacitor.

RESULT:-
 EXP-9

DC JONES CHOPPER
AIM: To construct a CHOPPER circuit and study its time ratio (TRC) controls.

Apparatus required:

S.No. Name of the equipment Range Qty

01 DC JONES CHOPPER power circuit

- 01
and firing circuit

02 C.R.O. with deferential module - 01

03 Patch chords and C.R.O. probes - Adequate

04 Regulated dc power supply 30V/2A 01

05 Variable Rheostat 0-100Ω / 2A 01

07 DC Voltmeter 0-100V 01

08 DC Ammeter 0-5A 01

CIRCUIT DIAGRAM:

PROCEDURE:

1. Circuit connections are made as shown in the circuit diagram by connecting rheostat
as the load. The gate cathode terminals of the 2 SCR’s are connected to the respective
point on the firing module.
2. Check all the connections and confirm connections made are correct before
switching on the equipments.
3. Keeping duty cycle knob at minimum position & input voltage at zero switch on the
firing and then power circuit.
4. Now gradually increase the input voltage up to 30V.
5. Keeping frequency constant vary duty cycle of the chopper firing circuit in steps and
note down corresponding load voltage for each step.
6. The output waveforms are seen on a CRO.
7. Keeping duty cycle at minimum position gradually decrease the input voltage.
8. Switch OFF the power circuit & then firing unit. Remove the patch cords.

TABULAR COLUMN:

FREQUENCY = _________HZ

VO
S.NO VIN TON TOFF DUTY CYCLE(δ)
practical theoretical

MODULE CALCULATIONS:

VO = δ* VIN

I O = VO / R
MODEL GRAPHS:

Load voltage waveform

T = TON + TOFF

𝟏
Frequency =
𝑻
𝑻𝑶𝑵
Duty cycle =
𝑻

RESULT:
 EXP-10

THREE PHASE HALF CONTROLLED BRIDGE CONVERTER WITH R& RL LOADS

AIM: To obtain the output waveforms of three-phase full wave half-controlled bridge

rectifier with R and RL load and with or without commutating or freewheeling Diode.

APPARATUS : MATLAB SOFTWARE

Circuit Diagram:

Procedure:

1. Make the connections as per the circuit diagram.

2. Verify the connections before simulating.

3. Set the value of resistance .

4. Connect the scope and simulate the circuit.

5. Observe output voltage waveform.

6. Note down readings of firing angle and output voltage.

7. Also calculate theoretical and practical values of output voltages and compare.

8. Repeat above steps for various firing angles.

9. For RL-load connect Inductance in series with resistance.

10. Repeat the above steps.

Model Graphs:
 EXP-11

PSPICE SIMULATION OF SINGLE PHASE AC VOLTAGE CONTROLLER

Aim:- To plot the output voltage and the load current using PSPICE of a 1-phase AC
voltage controller having a load of R=15 ohm, L=20 mh and the supply voltage is 169.7v,
╥
50Hz and the delay angle is = degrees.
6
Apparatus Required:-
 MicrosimEval software(PSPICE software)
 Personal computer

9.
Circuit diagram:-

Procedure:-
 Click on MicrosimEval in star menu and select Design Manager.
 Design Manager Window opens, in same window click on run Text Edit.
 Text Edit window opens, where the program code can be written.
 After completion of program, save it and close it.
 In the same Design Manager window, click on run Pspice A/D.
  A new window opens, now by clicking open menu, open the program, which is
saved.
 After the simulation is successful, by clicking the file menu, click on Run Probe.
 In the probe window, select add trace and select the required parameters and click
ok.
 Plot the graphs of respective outputs.

Program:-
*pspice simualtion of single phase ac voltage controller
vs 1 0 sin(0 169.7v 50hz 0 0 0)
vg1 7 3 pulse (0 10v 1.667ms 1ns 1ns 1000us 20ms)
vg2 6 2 pulse (0 10v 11.667ms 1ns 1ns 1000us 20ms)
xt1 2 3 7 3 scr
xt2 3 2 6 2 scr
r 3 4 15
l 4 5 20mh
vy 5 0 dc 0v
vx 1 2 dc 0v
.subckt scr 1 2 3 2
s1 1 5 6 2 smod
rg 3 4 50
dt 7 2 dmod
vx 4 2 dc 0v
vy 5 7 dc 0v
rt 2 6 1
ct 2 6 10uf
f1 2 6 poly(2) vx vy 0 50 11
.model smod vswitch(ron=0.0125 roff=10e+5 von=0.5v voff=0v)
.model dmod d(is=2.2e-15 bv=1200v tt=0 cjo=0)
.ends scr
.tran 1us 60ms 20ms 1us
.probe v(3,0),i(vx),i(vy),v(1,0)
.end
Output waveforms:-

Result:-
 Exp: 12

PSPICE SIMULATION OF RESONANT PULSE COMMUTATION

AIM:- To plot the capacitor voltage Vc and the capacitor current ic and the load current
iL using PSPICE of a resonant pulse commutation circuit and supply voltage is 200V.

Circuit diagram:-

Procedure:-
 Click on MicrosimEval in star menu and select Design Manager.
 Design Manager Window opens, in same window click on run Text Edit.
 Text Edit window opens, where the program code can be written.
 After completion of program, save it and close it.
 In the same Design Manager window, click on run Pspice A/D.
 A new window opens, now by clicking open menu, open the program, which is
saved.
 After the simulation is successful, by clicking the file menu, click on Run Probe.
  In the probe window, select add trace and select the required parameters and click
ok.
 Plot the graphs of respective outputs.

Program:-

*pspice simulation of resonant pulse converter

vs 1 0 dc 200v
vg1 7 0 pulse (0 20 0 1ns 1ns 0.4ms 1ms)
vg2 8 0 pulse (0 20 0.4 1ns 1ns 0.6ms 1ms)
vg3 9 0 pulse (0 20 0 1ns 1ns 0.2ms 1ms)
vx 6 0 dc 0v
vy 1 10 dc 0v
rg1 7 0 10MEG
rg2 8 0 10MEG
rg3 9 0 10MEG
l 2 3 6.4u
rm 4 5 6.3
lm 5 6 5mh
cs 1 11 0.1uf
rs 11 4 750
c 1 2 31.2u ic = 200
d1 4 1 dmod
dm 0 4 dmod
.model dmod d(is=2.2e-15 bv=1800v tt=0 cjo=0)
xt1 10 4 7 0 scr
xt2 3 4 8 0 scr
xt3 1 3 9 0 scr
.subckt scr 1 2 3 4
st 1 5 3 4 smod
dt 5 2 dmod
*va 2 4 0v
.model dmod d(is=2.2e-15 bv=1800v)
.model smod vswitch(ron=0.1 roff=10e6 von=10v voff=5v)
.ends scr
.tran 1us 4ms
.probe i(vx) i(vy) v(10,4) v(4,0)
.end

Output waveforms:-

Result:-
 Exp: 13

SINGLE PHASE INVERTER WITH PWM

AIM: PSPICE SIMULATION OF SINGLE PHASE INVERTER WITH PWM.

Q: The single phase inverter shown uses the PWM control with five pulses per half cycle

The dc supply voltage is vs. =100v, the modulation index M is 0.6, the out put
frequency

Is f0=60hz.the is resistive with R=2.5.Use pspice to plot output voltage.

CIRCUIT DIAGRAM:

(A) Circuit
PROGRAM:

* SINGLE PHASE INVERTER WITH PWM CONTROLER

VS 1 0 DC 100V

VR 17 0 PULSE (50V 0V 0 833.35US 833.3US 1NS 1666.67US)

RR 17 0 2MEG

VC1 15 0 PULSE (0 -30V 0 1NS 1NS 8333.35US 16666.6US)

RC1 15 0 2MEG

VC3 16 0 PULSE (0 -30V 8333.33US 1NS 1NS 8333.3US 16666.6US)

RC3 16 0 2MEG

R 4 6 2.5

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

*SUBCKT CALL FOR PWM CONTROL

XPW1 17 15 8 3 PWM

XPW2 17 15 10 0 PWM

XPW3 17 16 12 6 PWM

XPW4 17 16 14 0 PWM

*SUBCKT 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 3 750

CO 3 4 10PF

E1 6 4 0 5 2E+5

.ENDS PWM
.TRAN 10US 16.67MS 0 10US

.PROBE

.FOUR 60HZ V (3, 6)

.END

WAVEFORMS:

RESULT: The output voltage of single phase inverter with pwm is to be plotted.