Power Lectronics Lab Mannual

POWER ELECTRONICS LABORATORY

Laboratory Manual ForPOWER ELECTRONICSB.E (E.C)

SEM VII

Electronics & Communication DepartmentGovernment Engineering College Dahodwww.gecdahod.ac.inIndexName: _____________________________________ Roll No._____________

Sr.

NoExperiment TitlePageDate

Initials

of StaffRemark

FromTo

1To Study & Perform about the Characteristics of DIAC.

2To Study the Characteristics of a SCR and measure Holding Current (IH) And Latching Current (IL) of SCR.

3To Study the Characteristic of UJT.

4To Study the Characteristics of TRIAC

5To Obtain the most preferable mode of operation of TRIAC.

6To Perform UJT as a Relaxation Oscillator.

7To Study the Triggering Circuit using PUT.

8To Study and Perform Triggering scheme of SCR

9To Study & Perform the Phase Control of TRIAC with & without DIAC.

10To Study the Characteristics of MOSFET (Metal Oxide Semiconductor Field EffectTransistor)

11To Perform The Lamp Dimmer Circuit Using TRIAC.

12To Study the Thyristor Commutation Circuit

13To Study 3-Phase half-wave Uncontrolled & Controlled Rectifier

14To Study 3-Phase full-wave Uncontrolled & Controlled Rectifier

15To Study the Inverter Circuit

Experiment -1: DIAC characteristics

Date: ________1. Aim: To study & perform about the characteristics of DIAC.

2. Requirements: C.R.O, DIAC, Power supply 230V-50Hz, Multimeter, Connecting wires.3. Pre-Experiment Exercises

Brief Theory MT1 MT1 MT2 MT2 Fig:1 DIAC Structure Fig:2 DIAC Symbol

+I

Blocking State for MT1 (+) w.r.t. MT2 Ve Half Cycle

Conduction State for

+Ve Half Cycle

+IBO

-VBO -V+V

+VBO

-IBO Conduction State for

-Ve Half Cycle

MT1 (-) w.r.t. MT2-IFig: 3 Characteristics of DIAC

4. Laboratory Exercises A) Procedure:1. Connect the ckt as shown in fig.4.

2. Draw the voltage w/f and V-I characteristics of DIAC, when it conduct.

B) Observation Table1. Forward BiasSr.

No.Supply Voltage VsVoltage Across DIAC

VdCurrent Through DIAC Id

2. Reverse BiasSr.

No.Supply Voltage VsVoltage Across DIAC

VdCurrent Through DIAC Id

5. Post Experiment Exercises A) Conclusion B) Questions1. Why DIAC is named so?2. Which are the applications of DIAC ? 3. What is Break over voltage for DIAC ?Experiment-2: SCR Characteristics Date: ________1. Aim: To Study the Characteristics of a SCR and measure Holding Current (IH) And Latching Current (IL) of SCR.

2. Requirements: SCR, Circuit board, Power supply, Multimeter, Connecting wires

3. Pre-Experiment Exercises

Brief Theory

+IA

Forward voltage Drop

Latching Current

ig3 > ig2 > ig1

Holding

Reverse Break Current ig3 ig2 ig1 Down VoltageIH

ig=0

-V

Forward Forward

Leakage Break Over

Reverse Current Voltage

Leakage

Current

-IFig:4 V-I characteristics of SCR

4. Laboratory ExercisesA) ProcedurePart:1 Steps for SCR Characteristics1. Connect the circuit as shown in fig.3.2. Set the anode voltage (VAK) to some fix value (25v).

3. Now slowly increase the gate voltage and measure the reading of current IA, IG and voltage VAK.4. Repeat the step (3) until the SCR is Turn-ON.5. When SCR is ON, stop increasing the Gate voltage and measure the value IA, IGO and VAK, where IGO is the current requires to Turn-ON the SCR.

6. Now reverse the polarity of supply voltage VAK and take the reading for SCR reverse bias.7. Plot the V-I Characteristics of SCR from the observation table.B) Observations 1. Forward BiasSr.

No.Supply Voltage VsVoltage Across SCRCurrent Through SCR

2. Reverse Bias

Sr.

No.Supply Voltage VsVoltage Across SCRCurrent Through SCR

Part: 2 Steps for Measuring IH and IL1. Connect the circuit as shown in fig3.2. Set the gate current slightly higher then the IGO. 3. Now slowly increase the anode voltage (VAK) until the ammeter connected to anode shows some current reading (IA).

4 .Now turn-off the gate voltage and see if the Anode current meters reduce to zero value then again give the gate voltage and increase the anode voltage (VAK).

5. Repeat step 4 until you get the some reading on Anode current meter, even after removing the gate voltage. This current is known as Latching current (IL).

6. Now slowly reduce the anode voltage to zero so the Anode current meter readings also reduce to zero.

7. At one value of anode voltage the Anode current (IL) suddenly reduce to zero this current known as the Holding current (IH).

8. Note down the value of IH and IL.

5. Post Experiment Exercises A) ConclusionOperation of SCR1. Operation without gate

2. Operation with gateExperiment-3: UJT Characteristics Date: ________ 1. Aim: To Study The Characteristic of UJT.

2. Requirements: UJT circuit board, Power supply, Multimeter, Connecting wires 3. Pre-Experiment Exercises

Brief Theory

Cut offNegative

Saturation

RegionResistance Region

Region VpPeak Point

Valley Point VE (sat)

Vv

IP Iv 50 IE (mA)

IEO (A) Fig: 3 Characteristics of UJT

4. Laboratory Exercises A) Procedure

1. Connect the DC variable power supply and fixed power supply to their respective terminal with proper polarity.

2. Connect the meters for measuring current and voltage.

3. Increase the supply voltage until the UJT fires; record the maximum value of IE prior to firing of UJT as IP.

4. Tabulate the reading in the observation table.

5. Plot the graph of characteristics of UJT.

6. Make the conclusion.

B) Observations

Sr. No.Vs(volt)VE(volt)IE(mA)

5. Post Experiment Exercises

A) Conclusion

Experiment-4: TRIAC characteristics Date: ________1. Aim: To Study the Characteristics of TRIAC 2. Requirements: TRIAC circuit board, Power supply (0-60v), Multimeter, Connecting wires 3. Pre-Experiment Exercises

Brief Theory

4. Laboratory Exercises A) Procedure 1. Connect the circuit as shown in fig. 2.

2. Apply the minimum Gate current requires to turn on the TRIAC.

3. Slowly increase the supply voltage until the TRIAC comes in ON state. 4. Measure the reading of voltage and current for different value.

5 Reverse the polarity of supply and repeat the step 2 to 5.

6. Plot the V-I characteristic of TRIAC from the reading.

+ - - - +

330

1K

+

+

+

0-5V

G -

-

B) Observations1. Forward BiasSr.

No.Supply Voltage VsVoltage Across TRIACCurrent Through TRIAC

2. Reverse BiasSr.

No.Supply Voltage VsVoltage Across TRIACCurrent Through TRIAC

5. Post Experiment Exercises

A) Conclusion Experiment-5: The most preferable mode for TRIAC Date: ________1. Aim:- To obtain the most preferable mode of operation of TRIAC.2. Requirements: TRIAC circuit board, Power supply (0-60v), Multimeter, Connecting wires

3. Pre-experiment Exercises

Brief Theory

4. Laboratory Exercises A) Procedure

1. Connect the MT2 terminal in +ve and MT1 to ve and gate terminal to +ve. This is the I+ mode.

2. Now apply the supply voltage to TRIAC and increase the gate voltage until the TRIAC fired.

3. Measure this gate current as Ig and gate voltage as Vg and note down this value in the observation table.

4. Repeat the process for all the modes and measure the different value of Ig and Vg.

5. From the observation table find out the most preferable mode of TRIAC firing. ModeMT2MT1G

I++-+

ModeMT2MT1G

I-+--

ModeMT2MT1G

III+-++

ModeMT2MT1G

III--+-

Fig: 1. Mode of operation of TRIACB) ObservationsModeMT2MT1GGate Current Ig

I++-+

I-+--

III+-++

III--+-

5. Post Experiment Exercises A) Conclusion

Experiment-6: UJT as a Relaxation Oscillator

Date: ________

1. Aim: To perform UJT as a relaxation oscillator. 2. Requirements: UJT relaxation oscillator board, Power supply, CRO, Connecting wires

3. Pre-Experiment Exercise

Brief Theory

Fig.1 Circuit Diagram

4. Laboratory Exercise

A) Procedure

1. Connect the circuit as shown in fig.1.

2. Apply the supply voltage to UJT.

3. Observe the waveform across the UJT when it is in the off condition.

B) Observation Table

Sr. No.Practical Charging

Time,

T1Practical Discharging Time,

T2Value of RTheoretical Charging Time,

T1= 0.69*RCTheoretical Discharging Time,

T2 =0.69* RB1C

5. Post Experimental Exercise

A) Conclusion

Experiment-7: Triggering circuit using PUT

Date: _________ 1. Aim: To study the triggering circuit using PUT. 2. Requirements: PUT circuit board, Power supply, C.R.O, Connecting wires 3.Pre-Experiment Exercise

Brief Theory

Fig.1 Circuit Diagram4. Laboratory Exercise

A) Procedure

1. Construct the circuit shown in the figure.

2. Observe the waveform at G,A & K and draw them.


Sr.

No.RaTcTd


A) Conclusion

Experiment-8: Triggering scheme of SCR

Date: ________

1. Aim: To study and perform triggering scheme of SCR2. Requirements: SCR Trainer kit, Rheostat, CRO, Transformer, DMM3. Pre-Experiment Exercise

Brief Theory

Fig. 1 RC triggering Scheme of SCR 4. Laboratory Exercise

A) Procedure

1. Connect the circuit as shown in fig.1.

2. Apply the supply voltage to SCR.

3. Observe the waveform across the SCR when it is in the off Condition

4. Now adjust the value of resistor R2 to turn on the SCR and observe the waveform across it.

5. Find the firing angle and conduction angle of the SCR from the Waveform.

6. Vary the value of R2 and see the effect on the output waveform and take the different readings of conduction angle and compare it with the calculated value.


Sr No.TON secResistor

R2Firing

Angle Conduction

Angle,

= 180 -


A) Conclusion

Experiment-9: Phase Control of TRIAC With & Without DIAC

Date:________

1. Aim: To study & perform the phase control of TRIAC with & without DIAC.

2. Requirements: Circuit board, Rheostat, Voltmeter, CRO, Transformer, 3. Pre-Experiment Exercise

Brief Theory

Circuit diagram

Fig.1 Phase Control of TRIAC


A) Procedure1. Connect the circuit as shown fig.1.

2. See the waveform across TRIAC without connecting the DIAC.

3. Measure the TON time and conduction angle for both the half cycle.

4. Calculate conduction angle = on time *360/20.

5. Take different reading for different values of R and note down it.

6. Now connect the DIAC in the firing circuit of TRIAC and observe the wave form across the TRIAC.

7. Repeat the step 3 to 5.

8. Compare the both the reading of conduction angle for positive half cycle and negative half cycle.


With DIAC

Sr No.TON (ms)Calculated Angle

= TON 360 / 20msec

+ve-ve+ve-ve+ve-ve

Without DIAC

Sr No.TON (ms)Calculated Angle

= TON 360 / 20msec

+ve-ve+ve-ve+ve-ve


A) Conclusion

Experiment-10: Characteristics of MOSFET

Date: ________

1. Aim: To Study the Characteristics of MOSFET (Metal Oxide Semiconductor Field Effect Transistor)2. Requirements: Experimental board, Multimeter, Connecting wires.


Brief Theory


A) Procedure

1. Connect the DC variable power supply and fixed power supply to their respective terminal with proper polarity.

2. Connect the meters for measuring current and voltage.

3. Increase the supply voltage VIN in step of 1V with the help of pot when keeping VGS at a constant value.

4. Tabulate the reading in the observation table.

5. Now increase the value of VGS and repeat step 3and 4.

6. Plot the graph of characteristics of UJT.


A) Conclusion

Experiment-11: The Lamp Dimmer Circuit Using TRIAC Date: _______

1. Aim: To Perform The Lamp Dimmer Circuit Using TRIAC.

2. Requirements: Experimental Board, Multimeter, CRO, Resistance decade box, connecting wires.


Brief Theory

Circuit Diagram

Fig.1


B) Procedure

1. Construct the circuit shown in the figure.

2. Connect the oscilloscope across load. Dont connect probes directly to the load but use divider network and connect the probes there.

3. Vary the firing angle by varying the resistance using decade box and observe the waveforms.

4. Draw waveforms at 450 and 900 firing angles.


Sr No.Current IS(Amp)Load Voltage (VL)Thyristor Voltage VT(Volt)Variable Resistor-R(K)


A) Conclusion

Experiment-12: Thyristor Commutation Circuit

Date: ________

1. Aim: To Study the Thyristor Commutation Circuit

2. Requirements: Experimental board, Multimeter, connecting wires


Brief Theory


A) ConclusionExperiment-13: 3-Phase Half-wave Uncontrolled & Controlled Rectifier

Date: ________

1. Aim: To study 3-Phase half-wave Uncontrolled & Controlled Rectifier

2. Requirements: Trainer for 3-phase controlled-uncontrolled rectifier, CRO.

3. Pre-Experiment Exercise Brief Theory


B) Procedure

1. Connect the components such that 3-phase half wave uncontrolled rectifier will be developed.

2. Connect load across the DC+ and N terminal.

3. Connect oscilloscope across it using voltage divider and observe waveform.

4. Replace diode with the SCR and develop 3-phase controlled rectifier.

5. Repeat step 2 & 3.

Vary the phase control knob and see the waveform.


A) Conclusion

Experiment-14: 3-Phase Full-wave Uncontrolled & Controlled Rectifier

Date: ________

1. Aim: To study 3-Phase full-wave Uncontrolled & Controlled Rectifier

2. Requirements: Trainer for 3-phase controlled-uncontrolled rectifier, CRO.

3. Pre-Experiment Exercise Brief Theory


A) Procedure

1. Connect the components such that 3-phase full wave uncontrolled rectifier will be developed.

2. Connect load across the DC+ and DC- terminal.

3. Connect oscilloscope across it using voltage divider and observe waveform.

4. Replace 3 diodes with the SCR and develop 3-phase full wave half controlled rectifier.

5. Repeat step 2 & 3.

6. Vary the phase control knob and see the waveform.


A) Conclusion

Experiment-15: The Inverter Circuit

Date: ________1. Aim: To Study the Inverter Circuit2. Pre-Experiment Exercise

Brief Theory

Series Inverter:Operation:Disadvantages:3. Post Experimental Exercise

A) Conclusion

+

B1

Fig: 2 Symbol of UJT

EMBED Multisim.Document


+

-

4.7K

0-50V

+ -

Fig: 4 Circuit Diagram

MT1 MT2


I

V

Fig.2 TRIAC Circuit


I

I

V


-

+

E

+

-

MT1

MT2

ig3 > ig2 > ig1

Latching Current

Forward voltage Drop

-

+

0-5VDC

+

-

+

C=1F

C

R1 =

10K

230 AC

MT1

MT2


L

R

R1 = 1K

G


Bulb

Fig.4 Characteristics of MOSFET

0

VDS

VGS = -4

VGS = -3

VGS = -2

VGS = -1

VGS = 0

VGS = 1

ID

Fig.3 Circuit Diagram of MOSFET

+

VGS

VGG

-

0 5VDC

-

S

VDD

VDS

+

G

R1

D

ID

R2

Fig.1 Construction of N-Channel MOSFET

Fig.2 Symbol of N-Channel MOSFET

Source

Source

N

Gate

Gate

P

Substrate

Substrate

Oxide Layer

(SiO2)

N

Drain

Drain

+I

Fig: 4 Circuit Diagram of UJT Characteristic

0-10VDC

12VDC

330

Fig:3 Circuit Diagram for SCR Characteristic

I

R2

4.7K

-

-

+

-

-

-

G

MT2

330

-

MT1

+

+

1K

+

+

+

-

-

-

-

V

B2

K

G

A

0-50VDC

R1

1K

I

-

+

B1

B2

E

R3

R2

V

I

-

+

R1

4K7

-

-

+


47E

Anode Current(A)

G

0-30VDC

-

+

+

-

+

+

330

1K

MT1

MT2

G

0-30V

0-5V

V

I

I



0-30V

0-5V

V

I

I



+

-

-

-

+

+

+

-

-

+

330

1K

MT1

MT2

G

0-30V

0-5V

V

I

I



-

-

-

-

+

+

+

+

+

-

330

1K

MT1

MT2

G

0-30V

0-5V

V

I

I



Anode (A)

N

P

N

P

Cathode (K)

Gate (G)

j1

j2

j3

Fig:1 Construction of SCR

A

G

K

Fig:2 Symbol of SCR

Fig: 1 Construction of UJT

N-Type Bar

P-Type Bar

N

E

B1

B2

N

P

N

P

ig3 ig2 ig1

Holding

Current IH (mA)

Negative Break Down Voltage

-V

Reverse Leakage Current

Forward

Leakage

Current

Positive

Break Over

Voltage

Reverse

Voltage

Drop

-I

Anode Current(A)

+V

ig1 ig2 ig3

ig1 < ig2 < ig3

Fig: 1 V-I Characteristics of TRIAC

-

MT1

15 Vp-p AC

O/P

MT2

R1 = 1K

Rs = 70

+

D2

D1

A

K

C = 0.01F

R2 =

470K

G

R1 = 1K

Rs = 70

O/P

15 Vp-p AC

K

A G K

PUT

C=2.2nF

Rk=100

R2=6.7K

PUT

G

A

Ra=470K

+12V

R1=4.7K

RB1=47

RB2=330

R=1K

B1

B2

E

C=0.1F

R=0-100K

+12V

GEC DAHODB.E. EC

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