Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 7th Sem New 2172410 Power Electronics Design Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2172410 Date: 03/12/2018
Subject Name: Power Electronics Design
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) Enlist various attributes of ideal gate drive circuits. 03
(b) Draw the ideal shape of base drive pulse for power transistor and give circuit
configuration to produce such a base drive signal.
04
(c)
Discuss the steps in engineering design process for power electronics with appropriate
example
07
Q.2 (a)
Explain the concept of snubber Circuit.
03
(b) Discuss importance of isolation for gate drive circuit. 04
(c) Discuss crow-bar protection scheme using SCR. 07
OR
(c) An inductor is having rectangular core with following dimensions: Ag=Ac= 9
cm2, lg= 0.05 cm., lc= 30 cm., N= 500. ?
r
=72300 for core material. Find
inductance L of the winding, Where c stands for core; g stands for air gap.
07
Q.3 (a)
Explain multi-layer PCB in brief.
03
(b)
Explain Baker?s Clamp Circuit with diagram and also discuss requirements of it in base
driver circuit of Power Transistor.
04
(c)
Write a short note on SCR ratings.
07
OR
Q.3 (a) Derive the r.m.s value of current whose equation is given by
i(t)=5+10cos(wt+30).
03
(b) Give significance of proportional base control drive and also draw the driver
circuit for the same.
04
(c)
Enlist and explain the steps to design a transformer for line frequency power converters.
07
Q.4 (a) What is energy equation of inductor ? 03
(b) Describe the isolated gate driver for SCR with pulse transformer. 04
(c)
Describe the function of PUT with suitable example circuit.
07
OR
Q.4 (a)
Explain characteristics of UJT.
03
(b)
What is di/dt trouble for SCR ? Discuss remedies for the same.
04
(c)
Write a brief note on PCB designing
07
Q.5 (a) For a full wave rectifier minimum how many isolated power supplies will be
required for driver circuits ? Justify your answer.
03
(b) Describe the isolated base driver for MOSFET with opto-coupler IC. 04
FirstRanker.com - FirstRanker's Choice
Page 1 of 2
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2172410 Date: 03/12/2018
Subject Name: Power Electronics Design
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) Enlist various attributes of ideal gate drive circuits. 03
(b) Draw the ideal shape of base drive pulse for power transistor and give circuit
configuration to produce such a base drive signal.
04
(c)
Discuss the steps in engineering design process for power electronics with appropriate
example
07
Q.2 (a)
Explain the concept of snubber Circuit.
03
(b) Discuss importance of isolation for gate drive circuit. 04
(c) Discuss crow-bar protection scheme using SCR. 07
OR
(c) An inductor is having rectangular core with following dimensions: Ag=Ac= 9
cm2, lg= 0.05 cm., lc= 30 cm., N= 500. ?
r
=72300 for core material. Find
inductance L of the winding, Where c stands for core; g stands for air gap.
07
Q.3 (a)
Explain multi-layer PCB in brief.
03
(b)
Explain Baker?s Clamp Circuit with diagram and also discuss requirements of it in base
driver circuit of Power Transistor.
04
(c)
Write a short note on SCR ratings.
07
OR
Q.3 (a) Derive the r.m.s value of current whose equation is given by
i(t)=5+10cos(wt+30).
03
(b) Give significance of proportional base control drive and also draw the driver
circuit for the same.
04
(c)
Enlist and explain the steps to design a transformer for line frequency power converters.
07
Q.4 (a) What is energy equation of inductor ? 03
(b) Describe the isolated gate driver for SCR with pulse transformer. 04
(c)
Describe the function of PUT with suitable example circuit.
07
OR
Q.4 (a)
Explain characteristics of UJT.
03
(b)
What is di/dt trouble for SCR ? Discuss remedies for the same.
04
(c)
Write a brief note on PCB designing
07
Q.5 (a) For a full wave rectifier minimum how many isolated power supplies will be
required for driver circuits ? Justify your answer.
03
(b) Describe the isolated base driver for MOSFET with opto-coupler IC. 04
Page 2 of 2
(c) The maximum junction temperature of a bipolar junction transistor is TJmax = 150?C
and the maximum power dissipation is 2.0 W at ambient temperature TA = 25?C and
40 W at case temperature T C = 250C. Calculate the maximum allowable power
dissipation of the transistor operating in ambient temperature of 50?C in free air
environment.
07
OR
Q.5 (a) Compare active and passive heat sink. 03
(b) Explain totem pole configuration of MOSFET drive circuit. 04
(c)
Give the concept of thermal resistance. Describe the analogy between thermal and
Electrical quantities.
07
*************
FirstRanker.com - FirstRanker's Choice
This post was last modified on 20 February 2020