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Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 1
POWER ELECTRONICS LAB
Subject Code: 06ECL78 IA Marks : 25 No. of Practical Hrs/Week: 03 Exam Hours : 03 Total no. of Practical Hrs: 42 Exam Marks : 50
1. Static characteristics of DIAC
2. Static characteristics of SCR
3. Static characteristics of MOSFET
4. Static characteristics of IGBT
5. Controlled HWR and FWR using RC triggering circuit
6. SCR turn off using LC circuit
7. SCR turn off using Auxiliary Commutation
8. UJT firing circuit for HWR and FWR circuits
9. Generation of firing signals for thyristors/ trials using digital circuits/ Microprocessor 10. AC voltage controller using TRIAC – DIAC combination
11. Single phase Fully Controlled Bridge Converter with R and R‐L loads
12. Voltage (Impulse) commutated chopper both constant frequency and Variable frequency operations 13. Speed control of a separately exited DC motor
14. Speed control of universal motor
15. Speed control of stepper motor
16. Parallel / series inverter
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 2
Set of Experiment
I ‐ Cycle
1. Static characteristics of DIAC
2. Static characteristics of SCR
3. Static characteristics of IGBT
4. Controlled HWR and FWR using RC triggering circuit
5. Speed control of a separately exited DC motor
6. Single phase Fully Controlled Bridge Converter with R and R‐L loads
7. Generation of firing signals for Thyristors/ trials using digital circuits/ Microprocessor
8. SCR turn off using LC circuit
II‐Cycle
1. Static characteristics of MOSFET
2. UJT firing circuit for HWR and FWR circuits
3. Voltage (Impulse) commutated chopper constant frequency and variable frequency Operations 4. Parallel / series inverter
5. Speed control of stepper motor
6. SCR turn off using Auxiliary Commutation
7. AC voltage controller using TRIAC – DIAC combination
8. Speed control of universal motor
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 3
Experiment No.1
Static characteristics of DIAC
Aim : To determine the forward and reverse characteristic of DIAC
Apparatus Required: Resistor 1kΩ‐1No, Voltmeter (0‐60v)‐1 No, DIAC‐1No, Ammeter (0‐250mA)‐1No, Connecting Wires, Connecting Board‐1No. Circuit Diagram:
Procedure: (1). Rig up the circuit as shown in the circuit diagram (2). Switch on the Regulated power supply by keeping the voltage course fine in
minimum position (3). Increase the voltage in steps and note down the corresponding voltage and Current in the tabular column (4). Reduce the voltage to the minimum position and switch off the power supply (5). To determine the reverse characteristics interchange the DIAC terminals and repeat the above steps (6). Plot the graph of Voltage versus Current
Applications:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 4
Tabular Column: Forward
V ( volts) I (ma)
Reverse
V ( volts) I (ma)
Graph:
Result:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 5
Experiment No.2
Static characteristics of SCR
Aim: To determine the V‐I characteristics of the given SCR
Apparatus Required: Resistor 1kΩ, 470E/5w ‐1No, SCR TYN604/410‐1No, Voltmeter (0‐60v)‐1 No, Ammeter (0‐100mA)‐2No, connecting Board‐1No, Connecting Wires.
SYMBOL:
Circuit Diagram:
Procedure:
(1). Rig up the circuit as shown in the circuit diagram (2). Set Ig=7ma, Keeping Ig constant, vary the anode voltage VAK and note down
the anode current Ia and anode voltage Vak (3). Tabulate the readings and plot the graph of Vak Versus Ia (4). Repeat the above steps for for different gate current (Ig) (5). From the graph determine holding current (IH), Latching current (IL) and
Forward Break over voltage (VBO)
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 6
Applications: Graph:
Tabular Column:
I g =_____________ma
V ak (volts) I a (mA)
IL = ____________ma IH =____________ma Result:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 7
Experiment No.3
Static characteristics of MOSFET
Aim: To obtain the drain and transfer characteristics of MOSFET
Apparatus Required: Resistor 10kΩ, 50E/5w ‐1No, MOSFET (IRF 450)‐1No, Voltmeter (0‐60v)‐1 No, Ammeter (0‐100mA)‐2No, Connecting Board‐1No, Connecting Wires. SYMBOL:
Circuit Diagram:
Procedure:
(1).Rig up the circuit as shown in the circuit diagram (2).Switch on the power supply and keep Vgs to a constant value (1, 2,3V etc) (3).By varying the voltage across drain and source and note down the
corresponding voltage Vds and current Id (4).Tabulate the readings plot the graph of V ds v/s Id for different Vgs determine Rd
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 8
(5).To determine the transfer characteristics set Vds to a specified value and vary Vgs (6).For each variations of Vgs note down the drain current Id, tabulate the readings and plot the graph of Vgs v/s Id for constant Vds
(7). Determine the Tran conductance Gm and Amplification factor (µ) Rd = V ds / Id Gm= Id / Vgs µ = Gm* Rd Applications: Graph: Output Characteristics: Transfer Characteristics
Tabular Column: Output Characteristics
Vgs1= V ds (volts)
I d (mA)
Transfer Characteristics
Vds= V gs(volts)
I d (mA)
Result:
Vgs2= V ds (volts)
I d (mA)
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Page 9
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 10
Procedure:
(1). Rig up the circuit as shown in the circuit diagram (2). Switch on the supply by keeping in minimum position of Vge and Vce (3). Set the value for Vge=5.32v (4). Increase Vce in steps and note down the corresponding voltage of Vce and Current Ic (5).Tabulate the readings plot the graph of Ic versus Vce (6).To determine the transfer characteristics set Vce to a specified value (7). By increasing Vge in steps note down the corresponding values of Ic and plot the graph of Vge versus Ic for constant Vce Applications: Graph: Transfer Characteristics: Output Characteristics:
Tabular Column: V‐I Characteristics
Vge1= Vge2=
V ce (volts) I c(mA)
Vce1= Vce2= V ge(volts)
I d(mA) Result:
Transfer Characteristics
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 11
Experiment No.5
Controlled HWR and FWR using RC triggering Circuit
Aim: To rig up a circuit for controlled HWR and FWR using RC Triggering circuit
Apparatus Required: SCR (2P4M)‐2No, Diode (BY127)‐2No, Resistor 100E/5W, Pot 1M, Capacitor (0.47µF),Transformer (12‐0‐12) Voltmeter(0‐60v), Connecting Board, Connecting Wires and CRO probe.
Circuit Diagram:
HALF WAVE RECTIFIER
FULL WAVE RECTIFIER
v
v
230V 50HZ
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 12
INPUT AND OUTPUT WAVEFORMS:
Procedure:
(1). Rig up the circuit as shown in the circuit diagram (2). Switch on the Power supply (3). Observe the wave forms across SCR and Load for HWR and FWR (4). By varying the potentiometer (1M) note down the delay angle and output voltage (5).Compare the results with the theoretical value Vdc=Vm [1+cosα]/2π for HWR, Vdc=Vm [1+cosα]/π for FWR Tabular Column:
Delay Angle(α) V practical (volts)
V theoretical (volts) Applications: Result:
D
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A A
C
Department
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SCR t
Aim: To stud Circuit
Apparatus
Circuit Diag
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on
t No.6
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8
age 13
WR
1k, ,
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 14
HALF WAVE CONTROLLER
FULL WAVE CONTROLLER
Procedure:
(1). Rig up the circuit as shown in the circuit diagram (2). Switch on the A.C supply (3). Observe the wave forms at Vs, Va, Vz, Vc Vb1, VSCR and across the load (4). By varying the potentiometer (100K) note down the delay angle and output
voltage Applications:
SCR
6V/12V
1k
230V
B!6V/12V
R5
100E/5W
B2
2N2646
VB1
100k
VC
Vz1k
50Hz
VS 1k
Z6.5
0.47MF
VA
E
E
VB1
VS
2N2646
6V/12V
230V/50HZ
VA1k
B1
R8
1k
0.47MF
6V/12V
100k
Z 6.5
D
100E/5W
B2
1k
VC
SCR1
SCR2
VZVz
D
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 15
Result:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 16
Experiment No.7
SCR turn‐off using LC circuit
Aim: To study the basic working of LC Commutation Apparatus Required: Multimeter, Patch chords, CRO probes Circuit Diagram:
Procedure:
(1). Rig up the circuit as shown in the circuit diagram (2). Switch on the triggering circuit and observe the triggering pulses with the
help of CRO (3). Switch on the chopper switch keeping the potentiometer of the triggering
circuit in Minimum position (4). Note down the output Voltage, Duty cycle and Plot the graph
Tabular Column:
Applications:
VL (volts) Ton (ms) Toff (ms) T (ms) Duty Cycle
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 17
Graph: VL Duty cycle Result:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 18
Experiment No.8
SCR turn‐off using Auxilliary Commutation
Aim: To study the SCR Turn Off using Auxilliary Commutation Apparatus Required: Multimeter, Patch chords, CRO probes, Lamp load. Circuit Diagram:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 19
Procedure: (1). Rig up the circuit as shown in the circuit diagram (2). Switch on the triggering circuit and observe the triggering pulses with the help of CRO (3). Keep the selector switch of the DC supply in the second position i.e. 30V (4). Switch on the DC supply of the firing circuit keeping the chopper switch in the Off Position (5). Switch on the chopper switch keeping the potentiometer of the triggering circuit in the Minimum position (6). Observe the waveforms across the SCR, capacitor and Load (7). By varying the firing pulses measure Ton, Toff and output voltage across the Load (8). Compare the practical value with the theoretical value Vdc=Ton/Ton+Toff x Vin, Vdc=Ton/T x Vin, Vdc = duty cycle x Vin (9).Plot the graph of Duty cycle v/s output voltage Tabular Column:
Applications: Graph:
Result:
VL (volts) Ton (ms) Toff (ms) T (ms) Duty Cycle
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 20
Experiment No.9
Digital Triggering of SCR
Aim: To study the triggering of SCR using digital triggering Method Apparatus Required: Multimeter, Transformer (12‐0‐12), Resistor 100E/5w, Patch chords, CRO probes.
Circuit Diagram:
To HWR
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 21
Procedure:
(1). Switch on the Digital Triggering circuit module and check the Triggering pulses of the digital triggering using CRO
(2). Note down the wave forms at different terminal points of the module [A,C, Tp, Tn] (3). Rig up the circuit as shown in the circuit diagram (4). Vary the Triggering angle in steps and note down the output voltage [vdc]
across the load (5). Bring back the Triggering angle to zero and switch off the module (6). Plot the graph of vdc v/s α
Tabular Column:
Load Voltage (volts) Delay angle (α)
Applications: Graph:
Result:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 22
Experiment No.10
AC voltage controller using TRIAC‐DIAC combination
Aim: To study AC voltage controller Apparatus Required: TRIAC module, differential module, Lamp, Multimeter, BNC to BNC probe. Circuit Diagram:
Procedure: (1). Rig up the circuit as shown in the circuit diagram (2). Switch on the power supply to the circuit (3). Vary the potentiometer and note down the load voltage and delay angle (4). Plot the graph of delay angle versus voltage
Tabular Column:
Load Voltage (volts) Delay angle (α)
Applications: Graph:
Result:
D
Po
A A C
Department
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Single
Aim: To stud Conver
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Circuit Diag
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s
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 24
Procedure:
(1). Rig up the circuit as shown in the circuit diagram (2). Switch on the Triggering circuit and check the Triggering pulses with the help of CRO Keeping the potentiometer in minimum position (3). By varying the Triggering pulses note down the corresponding output voltage and Delay angle (4). Plot the graph of delay angle V/s output voltage (5). Decrease the Triggering pulses to the minimum position and switch off the circuit
Tabular Column:
Load Voltage (volts) Delay angle (α)
Applications: Graph:
Result:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 25
Experiment No.12
Speed control of separately excited DC Motor Aim: To study the speed control of separately excited DC motor using single phase full Wave half controlled rectifier Apparatus Required: Isolation transformer, patch cords, Multimeter, and Tachometer. Circuit Diagram:
Procedure: (1). Rig up the circuit as shown in the circuit diagram (2). Switch on the firing circuit and check the firing pulses with the help of CRO (3). Switch on the AC supply of the isolation transformer (4). By varying the firing circuit note down the output voltage and speed
Tabular Column:
Applications: Graph:
Result:
Load Voltage (volts) Speed (rpm)
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 26
Experiment No.13
Speed Control of Universal Motor
Aim: To study the speed control of Universal Motor Apparatus Required: TRIAC module, differential module, Universal motor, Multimeter.
Procedure: (1). Rig up the circuit as shown in the circuit diagram (2). Switch on the power supply to the circuit (3). Vary the potentiometer and note down the load voltage and speed (4). Plot the graph of voltage v/s speed
Tabular Column:
Graph:
Result:
Load Voltage (volts) Speed (rpm)
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 27
A1 A2 B1 B2Red Green Blue Black
0 1 0 10 1 1 01 0 1 01 0 0 1
Q1 Q2 Q3 Q4
Experiment No.14
Stepper Motor
Aim: To study the speed control of stepper motor Apparatus Required: Stepper motor, Stepper motor controller. Circuit Diagram:
SWITCHING LOGIC SEQUENCE
Half Step Full Step
A1 A2 B1 B2Red Green Blue Black
0 1 0 10 0 0 11 0 0 11 0 0 01 0 1 00 0 1 00 1 1 00 1 0 0
BLACK
RED
BLACK
GREEN
LOGIC CONTROLLER
BLUE
FREEWHEELING DIODES
SWITCHING TRANSISTORS
RS
+ ve
WHITE RS
-ve
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 28
Procedure: (1). Connect A1, A2, B1 and B2 leads of stepper motor to the corresponding Terminals of the Control module (2). Set the appropriate number of steps (3). Set the stepper motor to operate in half step or full step mode (4). Observe the rotation of the motor for different type of settings Motor Ratings: Permanent magnet, bifilar wound two phase Steps per revaluation : 200 No. of Leads : 06 Step angle : 1.80 + 02 – 0.10 non cumulative. 3 kg.cm = 0.1 N.m = 13.0 OZ – in Applications: Graph: Result:
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 29
Experiment No.15
Series Inverter
Aim: To study the basic working of series Inverter Apparatus Required: Inverter module, Patch chord, Multimeter, CRO probes, Resistor 50 Ω/5w, DC Power supply. Circuit Diagram:
Procedure: (1). Switch on the module to check the triggering pulses on the CRO (2). Rig up the circuits as shown in the circuits diagram (3). Switch on the power supply and observe the wave forms across the load (4). Measure the output voltage and output frequency by varying the frequency of the triggering circuits (5). Repeat the above procedure for different values of Inductance and
Capacitance (6). Bring back the triggering angle to zero and switch off the module
Tabular Column:
Inductance (H) Capacitance(µf) Frequency (Hz)
VL (volts)
T1 Firing Circuit T2
G
K
G K
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 30
Applications: Graph:
Result:
Resonance Frequency [Fr] =
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 31
Experiment No.16
Parallel Inverter
Aim: To study the basic working of parallel Inverter
Apparatus Required: Inverter module, Patch chords, Triggering module. Circuit Diagram:
Procedure: (1). Rig up the circuits as shown in the circuits diagram (2).Connect the +15, ‐15, Gnd and supply to the Triggering circuit. Check the
output of the trigger circuit at various points (3).Connect the gate of SCR1 and SCR2 to the triggering circuit and oscilloscope to the load (4).Observe the waveform and measure the frequency across the load
Applications: Graph:
Result:
Vdc
C
D2
D1
LKVL
-SCR1
+
SCR2
RL
T1 Firing Circuit T2
G
K
GK
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 32
MODEL QUESTION BANK
[1] Obtain the static characteristics of SCR and hence determine the holding current [2] Conduct a suitable experiment to determine VI‐ characteristics of uni‐directional four
layer switches. Determine breakdown voltage and holding current [3] Obtain a variable DC output voltage using LC communication and plot the graph of Duty
cycle v/s output voltage [4] Rig up and test an oscillator chopper circuit to produce variable DC output. Draw the
output voltage v/s duty cycle [5] Conduct a suitable experiment to obtain an output voltage of a fully controlled bridge
rectifier using resistive load. Plot the output voltage v/s delay angle [6] Conduct a suitable experiment to obtain an output voltage of a fully controlled bridge
rectifier for R and RL load with and without free wheeling diode. Plot the output voltage v/s delay angle for R load
[7] Conduct a suitable experiment to convert fixed DC voltage to variable DC voltage with the duty cycle of ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ and verify
[8] Conduct a suitable experiment to convert fixed DC voltage to variable DC voltage with a fixed frequency
[9] Conduct a suitable experiment to control the speed of a given DC motor using single phase half controlled bridge rectifier. Draw the speed v/s output voltage
[10] Control the RPM and step size of a stepper motor tabulate the readings for different settings
[11] Conduct a suitable experiment to obtain the AC output from a DC input using a basic series inverter
[12] Conduct a suitable experiment to verify the operating principle of a single phase series inverter
[13] For single phase fully controlled bridge rectifier circuit with R load plot the graph of Alpha v/s output voltage using digital firing circuit
[14] By conducting suitable experiment on a given MOSFET obtain the drain and transfer characteristics
[15] By conducting suitable experiment on a given MOSFET determine Rd, µ, gm [16] Conduct a suitable experiment to draw VI characteristics of the given IGBT and comment
on its switching characteristics [17] Conduct a suitable experiment to draw transfer and output characteristics of given IGBT [18] Conduct a suitable experiment to control intensity of light using bidirectional switch and
plot output voltage v/s delay angle [19] Conduct a suitable experiment to control the speed of a single phase universal motor and
plot the graph of output voltage v/s speed [20] Conduct a suitable experiment to trigger SCR using a UJT relaxation oscillator [21] Using RC only rig up a suitable experiment to trigger SCR and hence obtain the output
voltages for different angles
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 33
[22] Using RC triggering for HWR and FWR obtain firing angle v/s output voltage. Study the relevant waveforms
[23] Conduct a suitable experiment to obtain V‐I characteristics of a given 4‐layer 2 terminal device. Find the breakdown voltage for both directions
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 34
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 35
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 36
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 37
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Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 38
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 39
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 40
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 41
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 42
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 43
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 44
Department of Electronics and Communication DSCE, Bangalore‐78
Power Electronics Laboratory Page 45