Sinhgad Technical Educational Society’s
RMD Sinhgad School of Engineering, Warje, Pune-58.
Department of Electronics and Telecommunication
(T.E. semester-II) Prelim Examination-1 2022-23
Power Devices and circuits (304194)
Time: 2.30 hours
Max. Marks-70
Date -
Instructions to the candidates
1) Solve Q.1 Or Q. 2, Solve Q.3 or Q.4. , Q.5 or Q.6 and Q.7 or Q.8
2) Neat diagrams must be drawn wherever necessary.
Q.1
Q.2
Q.3
Q.4
a)
b)
Explain working of square wave full bridge inverter with RL load(waveform)
How to generate gate pulse to switches in case of PWM inverter?
OR
a) Explain working of 3-phase inverter in 1200 conduction with R load
b) Compare 3-phase inverter 1200 conduction and 180 0 conduction mode
(9)
(9)
a)
(8)
Explain with neat circuit diagram operation of the step up chopper. Derive an
expression for its output voltage
b) Explain with block schematic working of SMPS. What are its advantages over
linear power supply?
OR
a) A single phase full wave ac voltage controller has a resistive load of R=10Ω
and input voltage is Vs=120V(rms), 50Hz. The delay angles of thyristors are
equal: α1=α2=π/2. Determine i) rms output voltage ii) the rms output current iii)
the input PF.
b) Explain with neat circuit diagram operation of the step down chopper. Derive
an expression for its output voltage.
Q. 5 a)
b)
Q. 6
a)
b)
Q7
(9)
(8)
(9)
Explain with circuit diagram & waveforms working of Zero voltage switching
(9)
(ZVS)
What is electromagnetic interference (EMI)? Explain various sources & (8)
minimizing techniques of EMI. And also explain overvoltage protection circuit
OR
Write short note on overvoltage and overcurrent protection circuits and also
(9)
Explain working of metal oxide varistors
For as thyristor, maximum junction temperature is 125oC. the thermal (8)
resistances are Rᶿjc=0.16 oC/W, Rᶿcs=0.08oC/W for a heat ssink temperature of
70oC, calculate total average power loss in thyristor – sink combination. If heat
sink temperature is reduced to 60oC, find new total average power loss in
thyristor – sink combination.
a) Draw and explain AC Voltage controller using SCRs for R load
b) Explain various selection criteria of batteries in battery operated power systems.
OR
Q. 8 a) Explain speed control of separately excited DC motor using controller rectifier.
b)
(9)
(9)
(9)
(9)
(9)
Draw and explain in detail Architecture of EVs battery charger.and aslo write (9 )
short note on UPS
Sinhgad Technical Educational Society’s
RMD Sinhgad School of Engineering, Warje, Pune-58.
Department of Electronics and Telecommunication
(T.E. semester-II) Prelim Examination-1 2022-23
Power Devices and circuits (304194)
Time: 2.30 hours
Max. Marks-70
Date -
Instructions to the candidates
1) Solve Q.1 Or Q. 2, Solve Q.3 or Q.4. , Q.5 or Q.6 and Q.7 or Q.8
2) Neat diagrams must be drawn wherever necessary.
Q.1
Q.2
Q.3
Q.4
a)
b)
Explain working of square wave half bridge inverter with RL load(waveform)
Explain PWM inverter?
OR
a) Explain working of 3-phase inverter in 1800 conduction with R load
b) Compare 3-phase inverter 1200 conduction and 180 0 conduction mode
(9)
(9)
a)
(8)
Explain with neat circuit diagram operation of the step up chopper. Derive an
expression for its output voltage
b) Explain with block schematic working of SMPS. What are its advantages over
linear power supply?
OR
a) A single phase full wave ac voltage controller has a resistive load of R=10Ω
and input voltage is Vs=120V(rms), 50Hz. The delay angles of thyristors are
equal: α1=α2=π/2. Determine i) rms output voltage ii) the rms output current iii)
the input PF.
b) Explain the buck and boost converter .
Q. 5 a)
b)
Q. 6
a)
b)
Q7
(9)
(8)
(9)
Explain with circuit diagram & waveforms working of Zero Current switching (9)
(ZCS)
What is electromagnetic interference (EMI)? Explain various sources & (8)
minimizing techniques of EMI. And also explain overvoltage protection circuit
OR
Write short note on Online ups and offline ups
(9)
For as thyristor, maximum junction temperature is 125oC. the thermal (8)
resistances are Rᶿjc=0.15 oC/W, Rᶿcs=0.07oC/W for a heat ssink temperature of
70oC, calculate total average power loss in thyristor – sink combination. If heat
sink temperature is reduced to 60oC, find new total average power loss in
thyristor – sink combination.
a) Draw and explain AC Voltage controller using IGBT for R load
b) Explain the 3 phase variable voltage and frequency induction motor.
OR
Q. 8 a) Explain speed control of separately excited DC motor using controller rectifier.
b)
(9)
(9)
(9)
(9)
(9)
Draw and explain in detail Architecture of EVs battery charger.and aslo write (9 )
short note on UPS