Download PTU. I.K. Gujral Punjab Technical University (IKGPTU) M.Tech. EE 1st Semester 70726 ADVANCED POWER ELECTRONICS Question Paper.

1 | M-70726 (S9)-1876

Roll No. Total No. of Pages : 01
Total No. of Questions : 08
M.Tech.(EE) (2013 Onwards) (Sem.?1)
Subject Code : MTEE-102
M.Code : 70726
Time : 3 Hrs. Max. Marks : 100

INSTRUCTION TO CANDIDATES :
1. Attempt any FIVE questions out of EIGHT questions.
2. Each question carries TWENTY marks.
1. a) Discuss the turn-off mechanism of a Thyristor. Draw well labelled circuit diagrams
with proper explanation.
b) Compare and contrast a power IGBT with a power transistor.
2. a) Justify the following statement : ?The Thyristor exhibits the property of Hysterisis?.
b) Develop the thermal mode of the thyristor and explain its use.
3. a) Explain in detail the power MOSFET circuit and the construction of a vertical
channel diffused MOS power MOSFET. Draw the schematic diagram.
4. Calculate the switching losses of an IGBT for the following conditions both for the
cc
= 200 V; tf1 = 0.5 ?s ; l
CM
= 50A;
t
rv
= 0.5 ?s; f = 20kHz; tf2 = 2.5 ?s; t
rv
= 0.5 ?s, where l
CM
is the maximum value of
collector current, t
rv
is the collector to emitter voltage-rise time.
5. Explain the turn-off characteristics (Voltage and current) of a GTO. By making use of the
snubber circuit for a GTO ,explain in detail, its role in the GTO circuits.
6. a) What are de-coupled Drive circuits?
b) Give a firing circuit for a thyristor that uses a saturable reactor. Explain how a
thyristor gets triggered with a high dv/dt.
7. a) What are the losses in a MOSFET ? Find out the expression for each one of them.
b) What precautions have to be taken for MOSFETS to operate in parallel?
8. a) What is a latch-on in an IGBT? What steps have to be taken to avoid it?
b) How many types of Power Integrated circuits (PICs) are there? What are their fields
of applications?
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