Anna University
Department of EEE
Department of EEE
Semester : 5
Year : 3
Note :
Answer to these questions page no is given based on the Book : Power Electronics by Dr.J.S.Chirode (Technical Publication) - Reprint July 2011
Part A
1.Advantage of IGBT over MOSFET.
Answer : Page no : 1.139
2.Define Switching losses
3.Define Pinchoff voltage of MOSFET.
Answer : Page no : 1.138
4.State Requirement of Gate drive.
Answer : Page no : 1.33
5.Define Commutation of Thyristor.
6.Difference Between Natural and Forced Commutation.
Answer : Page no : 1.143
7.Define Displace factor.
Answer : Page no : 2.113
8.Under What condition a single phase fully controlled gets operated as an inverter ?
Answer : Page no : 2.113
9.Advantage of semi converter bridge over full converter bridge.
10.In class D commutation circuit Vs = 230v , L = 20mh , C= 40mf. Calculate Peak value current through capactance through main auxillary thyristor.
Part B
11.Explain Different modes of Thyristor with the help of VI Characteristics.
12. Explain IGBT.
Answer : Page no : 1.65
13. Explain MOSFET.
Answer : Page no : 1.59
14. Explain Operation of Single Phase Full Converter with neat diagram and expression for RMS and output voltage for RLE.
15. A Single phase full converter is supplied from 230 V, 50 Hz source. The Load consists of R = 10 ohm and a large inducatance so as to render the load current constant. For a firing angle delay of 30 , determine :
i) Average output voltage,
ii) Average output current,
iii)Average and rms values of thyristor currents,
iv) The Power factor.
Answer : Page no 2.40