Download GTU BE/B.Tech 2018 Winter 7th Sem Old 171002 Power Electronics Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 7th Sem Old 171002 Power Electronics Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ?VII (OLD) EXAMINATION ? WINTER 2018
Subject Code: 171002 Date: 19/11/2018

Subject Name: Power Electronics

Time: 10:30 AM TO 01:00 PM Total Marks: 70

Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) List the different members of the thyristor family and draw their characteristics
and explain in brief.

07
(b) Explain single phase half wave rectifier with suitable circuit and waveform.

07

Q.2 (a) Explain the operation of the SCR using the Two transistor analogy. Obtain
the condition for the breakdown of the device. Derive an expression for
the anode current IA using this analogy.


07
(b) Sketch switching characteristics of Thyristor during its turn ON and turn OFF
processes. Discuss briefly the nature of these curves.

07
OR
(b) Draw and explain circuit of 3 phase semiconverter with RL load with
freewheeling diode for ? = 60?.

07

Q.3 (a) Draw and explain SCR V-I characteristics with required terms. 07
(b) Explain the DC Chopper?s principal of operation. 07
OR
Q.3 (a) Explain Single phase Full (Bridge) controlled rectifier for R & RL load in detail
with relevant waveform.
07
(b) Write short note on dual converter.

07

Q.4 (a) Discuss the pulse width modulated inverter.

07
(b) What is inverter? List few industrial applications of inverters. Explain basic
series inverter.

07
OR
Q.4 (a) Explain various thyristor turn-on methods.

07
(b) Write short note on step-up chopper.

07

Q.5 (a) Compare dielectric heating with induction heating

07
(b) What is SMPS? Give classification of SMPS. Also explain any one of the SMPS. 07
OR

Q.5 (a) Compare SCR, power MOSFET and IGBT.

07
(b) Explain the operation of UPS system

07

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