Download GTU BE/B.Tech 2017 Winter 7th Sem Old 170801 Power Electronics And Industrial Drives Question Paper

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Subject Code: 170801

GUJARAT TECHNOLOGICAL UNIVERSITY

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BE - SEMESTER - VII EXAMINATION - WINTER 2017

Subject Name: Power Electronics & Industrial Drives

Time: 10:30 am to 01:00 pm

Date: 18-11-2017

Total Marks: 70

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Instructions:

1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

1. (a) Describe the operation of full wave uncontrolled rectifier with R-L load with neat sketch and necessary waveforms. [07]

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2. (b) Draw and explain the structure of power MOSFET. Also explain the principal of operation and I-V characteristics of power MOSFET. [07]

1. (a) Explain with neat sketch the 1-Φ full wave controlled rectifier with R-L load using its waveforms and equations. [07]
2. (b) With neat sketch, explain two-transistor analogy of SCR in detail. [07]

OR

1. (a) Draw and explain 3-Φ half wave controlled rectifier with required waveforms and equations. [07]

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2. (b) List the power factors improvement methods for phase controlled rectifiers and explain any one in detail. [07]

1. (a) Discuss 3-Φ AC to AC converter with star connected resistive load. [07]
2. (b) Explain with neat sketch the operation of 1Φ cycloconverter with necessary waveforms. [07]

OR

1. (a) Explain the voltage protection by selenium diode and metal oxide varistors in detail. [07]

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2. (b) Discuss the operation of current/source inverter with necessary waveforms. [07]

1. (a) Explain the following PWM methods for control of 1-Φ inverter.
   • Single Pulse Width-Modulation
   • Sinusoidal Pulse Width Modulation
   [07]

OR

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1. (b) Briefly discuss the operation of 3-Φ inverter for 120° mode of conduction. Draw necessary waveforms. [07]

1. (a) Discuss the role of Snubber Circuit from protection aspect. [07]
2. (b) What is DC drive? Discuss the basic characteristics of DC Motors. [07]

1. (a) Explain V/f control of Induction Motor Drives with its merits and demerits. [07]
2. (b) Briefly discuss the performance characteristics of Induction Motor. [07]

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OR

1. Discuss about the choice of A.C. & D.C. drives in detail. [07]