Pune University BE Electronics Advanced power Electronics Question Papers

B.E. (Electronics) ADVANCED POWER ELECTRONICS (2008 Pattern) (Elective – I) (Sem. – I)

Time :3 Hours]                                                                                              [Max. Marks :100

Instructions to the candidates :

1)            Answer 3 questions from Section -1 and 3 questions from Section – II.

2)            Answers to the two sections should be written in separate books.

3)            Neat diagrams must be drawn wherever necessary.

4)            Pigures to the right indicate full marks.

5)            All questions carry equal marks.

6)            Use of logarithmic tables, slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed.

7)           Assume suitable data if necessary.


QI) a) What is the need of PWM technique in converter circuits? Explain with circuit diagram 8 waveforms, working 3 ^ IGBT based PWM rectifier with suitable load. Comment on Pf 8 hormonics.             [10]

b)                Explain, EMI 8 power quality problem of Thyrister converter. [6]


Q2) a) What is power conditioning of diode rectifier? Explain.                                                                                                                                                                                                 [6]

b)                What is the need of 12 pulse converter in heavy industries? Justify how it improves the system performance as compare to conventional converters.                              [10]

Q3) a) What is Phase Locked Loop Control System? Explain with diagram speed control of DC Motor using PLL for varying load conditions. State its advantages 8 dis-advantages.            [10]

b)                Explain the need of (c based DC drive in industries.                                                                                                                                                                                  [6]


Q4) a) What are AC drives? Explain with block diagram 3 ^ , reversible Flux Control for IM drive. State its advantages and disadvantages. [8]


b)            Justify why cycloconverter based IM are not recommended for high power industrial applications.                                                                                                        [8]

Q5) a) What are different types of modulation techniques used in inverters?

Explain any one type. State its advantages.                                                   [6]

b)            What is the need of DC-Link inverter? State its advantages and disadvantages.         [6]

c)            What is adaptive control? Explain.                                                                 [6]


Q6) a) What are Multi-Level Inverters? Explain with circuit diagram switching of Multi-level inverters. State its advantages 8 dis-advantages. [10]

b)                                                                                                                                                                                                                                                                                            Write short notes on any two :                                                                                                                 [8]

i)             Z – source inverters.

ii)           Space vector modulation.

iii)        Double sided converter system.

iv)                            UPS.


Q7) a) What is soft switching in Resonant converter? Explain with circuit diagram 8 waveforms, working SLR converter.                                        [10]

b)                                                                                                                                                                                                                                                                          What is hot swappable redundant Power Supply? Explain.                                                      [6]


Q8) a) Explain the difference between single 8 Multi-resonant converter. [8]

b)            What is ZCS? Explain with circuit dia 8 waveforms working of ZCS. State its advantage 8 dis-advantages over ZVS.                                                                    [8]

Q9) a) What are different types of Renewable energy sources? Explain the role of DC – to DC converter in variable wind energy y-conversion system.


b)            What is the role of Power Electronic Converters (PEC’s) in Wind Power Plants (WPP’s).                                                                                                               [8]


QIO) a) What are battery powered drives? Explain.                                    [6]

b)            Explain in brief, Photovoltalic energy conversion system.                        [6]

c)            What is the role of Back to Back Power Electronic Converters (PEC’s)

8               state its Limitations.                                                                                           [6]

Qll)a) What is solar power conditioning? Explain in brief.                                           [6]

b)            What is power quality? Mention different power line disturbances. Suggest preventive 8 nullifying measures for these disturbances.                                                [10]


Ql2)Write short notes on any three :                                                                                [16]


Traction drives.


Universal Motors.




Battery chargers.


Cascaded Multi-Level Inverters.




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