Download PTU B.Tech 2020 March EE 6th Sem Power Electronics Question Paper

Download PTU (I.K. Gujral Punjab Technical University Jalandhar (IKGPTU) ) BE/BTech EE (Electrical Engineering) 2020 March 6th Sem Power Electronics Previous Question Paper

1 | M-72789 (S2)-1621
Roll No. Total No. of Pages : 02
Total No. of Questions : 09
B.Tech. (EE) PT (Sem.?6)
POWER ELECTRONICS
Subject Code : BTEE-504
M.Code : 72789
Time : 3 Hrs. Max. Marks : 60
INSTRUCTIONS TO CANDIDATES :
1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks
each.
2. SECTION-B contains FIVE questions carrying FIVE marks each and students
have to attempt any FOUR questions.
3. SECTION-C contains THREE questions carrying TEN marks each and students
have to attempt any TWO questions.

SECTION-A
1. Answer briefly :
a. Define latching and holding current of a thyristor.
b. What do you understand by PIV rating of a thyristor?
c. What is a snubber and why is it used?
d. What is phase control in a thyristor?
e. What is the purpose of a chopper?
f. What is feedback diode and where is it used?
g. What is di/dt and dv/dt ratings of a thyristor?
h. Why and where the zener diode is used for thyristors?
i. Can a converter be used as an Inverter? If yes how and if no why?
j. Differentiate between SUS and SCS.
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1 | M-72789 (S2)-1621
Roll No. Total No. of Pages : 02
Total No. of Questions : 09
B.Tech. (EE) PT (Sem.?6)
POWER ELECTRONICS
Subject Code : BTEE-504
M.Code : 72789
Time : 3 Hrs. Max. Marks : 60
INSTRUCTIONS TO CANDIDATES :
1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks
each.
2. SECTION-B contains FIVE questions carrying FIVE marks each and students
have to attempt any FOUR questions.
3. SECTION-C contains THREE questions carrying TEN marks each and students
have to attempt any TWO questions.

SECTION-A
1. Answer briefly :
a. Define latching and holding current of a thyristor.
b. What do you understand by PIV rating of a thyristor?
c. What is a snubber and why is it used?
d. What is phase control in a thyristor?
e. What is the purpose of a chopper?
f. What is feedback diode and where is it used?
g. What is di/dt and dv/dt ratings of a thyristor?
h. Why and where the zener diode is used for thyristors?
i. Can a converter be used as an Inverter? If yes how and if no why?
j. Differentiate between SUS and SCS.
2 | M-72789 (S2)-1621
SECTION-B
2. Discuss the transient characteristics of a thyristor and explain various terms used in it.
3. Differentiate between line and load commutations of a thyristor.
4. Explain the operation of a current commutated chopper with the help of its waveforms.
5. Explain the operation of a single-phase bridge inverter with the help of circuit diagram
and associated waveforms.
6. Discuss the PWM control for reduction of harmonics in the inverter output voltage.

SECTION-C
7. Discuss the need of static and dynamic equalization for the series and parallel operation
of thyristors? Also discuss various protection circuits used for thyristors.
8. Draw the circuit diagram of a three-phase bridge converter and explain its operation with
the help of various waveforms.
9. Write short note on any of two :
a. Single phase bridge cyclo-converter.
b. Modified Mc-Murray Half bridge Inverter.
c. Classification of choppers.






NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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