## December 3, 2011

### EE1351 SOLID STATE DRIVES question papers Anna university question papers NOVEMBER/DECEMBER 2007 Download

B.E/B.Tech DEGREE EXAMINATION NOVEMBER/DECEMBER 2007

Sixth Semester

Electrical and Electronice Engineering

EE 1351 -- SOLID STATE DRIVES

(Regulation 2004)
Time: Three hours                                                    Maximum marks: 100

PART A (10 x 2 =20 marks)

1. what is the principle of regenerative braking?

2. Draw the complete speed - torque curve of induction motor.

3. Is a sine - wave output current possible from a chopper circuit.

4. What are the two types of current controllers used in motor drive system?

5. Write any two applications of slip - power recovery drives in induction motors.

6. What is meaning of voltage - fed inverter locomotive drive with parallel machines?

7. Write any two applications of synchronous motor drives.

8. Write any four special features of self - controlled synchronous machine.

9. What is current controller and how it is represented in the form of simple equation?

10. Write the transfer function equation for a D.C motor.

PART B (5 x 16 = 80)

11 (i) Draw the typical speed - torque characteristics of D.C shunt motor, D.C series motor, 3 phase induction motor. (8)

(ii) Explain the principle of regenerative braking used in four - quadrant industrial drives. (8)
(or)
(b) (i) Explain the concept of steady state stability condition in industrial drives. (8)

(ii) Write equations governing D.C motor load dynamics. (8)

12. (a) Discuss the control circuit design for a two - quadrant chopper circuit. (16)
(or)
(b) Evaluate the instantaneous steady-state armature current and electromagnetic torque including harmonics for continuous current conduction mode for a chopper controlled d.c motor drive. (16)

13 (a) (i) Explain with diagrams a speed control system of a Kramer drive and its typical performance for a three phase induction motor. (8)

(ii) Derive the relationsip between stator voltage and stator frequency and draw corresponding graphs for a three phase induction motor. (8)
(or)
(b) (i) Explain with diagrams a minimal closed loop control system of a current - fed inverter system and its performance characteristics.(8)

(ii) Describe with a diagram the open loop volts/Hz control of an induction motor. (8)

14. (a) Draw the open loop volts/Hz speed control of multiple PM synchronous motors and volts/Hz speed control characteristics in torque - speed plane.(16) <
(or)
(b) Explain the special features of self controlled synchronous motor with diagram and differences between this and a d.c motor. (16)

15. (a) Draw and explain a close loop speed control system of a BLDM drive with the inverter operating in PWM feed back mode. (16)
(or)
(b) Explain with diagram a control schematic of the four - quadrant d.c motor drive. (16)