Geetanjali Institute of Technical Studies,Udaipur
Branch/Sem:EE/VI Sem
Subject: Advanced Power Electronics (6EE4A)
Faculty Name: Bheru Das
Unit- I
1. What is an AV voltage controller? List some of its industrial applications. Enumerate its
merit and demerits.
2. For a single phase ac voltage controller feeding a resistive load, show that power factor is
given by expression[ {(
)
}]
⁄
3. An ac voltage controller in figure has a resistive load of R = 10ohm the root-mean-square
(rms) input voltage is Vs = 120V, 60Hz. The Thyristors switch is on for n=25 cycles and
is off for m=75 cycles. Determine
a) The rms output Voltage Vo,
b) The input power factor (PF), and
c) The average and rms current of thyristors.
4. What are the steps involved in determining the output voltage waveforms of three –
phase bidirectional controllers?
5. A single phase half wave AC voltage controller feed power to a resistive load of 6ohm
from 230V, 50 Hz source.
The firing angle of SCR is π/2 calculate1. RMS value of output voltage
Geetanjali Institute of Technical Studies,Udaipur
2. Input power factor.
3. Average input current
6. Explain the principle of phase control .
7. Explain the principle of integral cycle control.
8. Write short notes on AC Voltage Controller with PWM Control.
9. What is the control range of the delay angle for single – phase unidirectional controller?
10. Explain single phase voltage controller with inductive load and draw various output
waveforms.
Unit-II
1. Explain the basic principle of operation of three phase cycloconverter.
2. Show that the fundamental rms value of per phase output voltage of low frequency for
an m-pulse cycloconverter is given by
Vrms = Vph (m/π) sin(π/m)
3. Discuss why 3-phase to 1-phase cycloconverter requires positive and negative group
phase controlled converters. Under what conditions, the group works as inverter or
rectifier?
4. Write short notes on three phase to three phase cyclo converter using 36 thyristor.
5. A 6 pulse cycloconverter, fed from 3 phase, 440 V, 50 Hz source, is delivering a load
current of 40 A to a 1 phase resistive load. The source has an inductance 1.2 mH per
phase. Calculate the rms value of load voltage for firing angle delays of (a) 00 ( b) 300
Geetanjali Institute of Technical Studies,Udaipur
6. Explain three phase to single phase cycloconverter.
7. A single-phase bridge-type cycloconverter has input voltage of 230 V, 50 Hz and load
R= 10 ohm . Output frequency is one third of input frequency. For the firing angle delay
of 300 calculate
(a) rms value of output voltage
(b) rms current of each converter.
8.
A single-phase bridge-type cycloconverter has input voltage of 230 V, 50
Hz and load R= 10 ohm . Output frequency is one third of input frequency.
For the firing angle delay of 300, calculate input power factor and rms
current of each thyristor.
9.
Write short notes on three phase to three phase cycloconverter using 18
SCR.
10. What is cycloconverter? List some of its industrial applications
Unit-III
1. Draw the schematic of a three phase current source inverter and describe its operation.
2. Describe the operation of 180˚ mode of conduction for inverter. Why this inverter is
called quasi-square wave inverter?
3. With the help of neat circuit diagram & waveform, explain briefly the operation of threephase bridge inverter with resistive load in 120˚ conduction mode.
4. Explain voltage control of single phase & three phase inverters.
5. Explain single phase bridge type inverter with RL load.
6. Write short notes on reduction of harmonics in the inverter.
7. Explain single phase Current source inverter.
8. A single phase full bridge inverter is fed from a dc source such that fundamental
component of output voltage is 230 V. Find the rms value of thyristor and diode currents
for the load R=2 ohm.
9. Short notes on PWM inverter.
10. Explain single phase Half wave inverter with R load.
Geetanjali Institute of Technical Studies,Udaipur
Unit-IV
1. Explain working of ZVS resonant converter.
2. Explain working of class E resonant inverter with the help of neat circuit diagram &
waveform.
3. Explain working of M-type ZCS resonan converter with the help of neat circuit diagram
& waveform.
4. Explain working of L-type ZCS resonan converter with the help of neat circuit diagram
& waveform.
5. Short notes on parallel resonant inverter.
6. Write the difference ZCS and ZVS.
7. Explain working of Series resonant inverter with unidirectional switches.
8. What is resonant converter? List some of its industrial applications.
Unit-V
1. Explain Resonant AC power supply.
2. Explain the concept of ac power supplies or UPS. What are the types of ac power supplies
available?
3. With a neat sketch, explain multistage conversion.
4. Discuss current mode control and voltage mode control in ac power supplies.
5. Write a short note on: Switch mode DC power supplies.
6. Write a short note on: Bi-directional power supplies.
7. Explain the operation of Resonant DC power supply.
8. Derive an expression for voltage transfer ratio Vo/Vs in terms of transformer turns ratio
and duty cycle for fly back converter, operating with continuous load current.
9. Explain the principle of fly back and forward converter.
10. Explain the voltage mode control of forward converter.
Geetanjali Institute of Technical Studies,Udaipur