VALLIAMMAI ENGINEERING COLLEGE DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION Sem / Branch : V /EIE Subject code /Title: EI2301/Industrial Electronics UNIT-1 POWER DEVICES 1. What are the different methods to turn on the thyristor? 2. What are the types of power transistor? 3. Define latching current. 4. Define holding current. 5. What is a snubber circuit? 6. Why IGBT is very popular nowadays? 7. What is the difference between power diode and signal diode? 8. What are the advantages of GTO over SCR? 9. What losses occur in a thyristor during working conditions? 10. What do you mean by load commutation? 11. What do you mean by controlled switch? 12. What is the need of driver circuit? 13. Why are IGBT becoming popular in their application to controlled converters? 14. What are the factors that influence the turn-off time of a thyristor? 15. Write the merits and demerits of MOSFET over BJT. 16. Distinguish between holding current and latching current of SCR 17. Define the term pinch off voltage of MOSFET. 18. How a thyristor can be protected against excess dv/dt? 19. In TRIAC which of the modes the sensitivity of gate is high. 20. How SCR differs from TRIAC? 21. State the advantages of IGBT over MOSFET. 22. Draw the VI characteristics of TRIAC. 23. What is commutation? What are the two main types of commutation? 24. Draw the VI characteristics of SCR and mark the holding current and latching current in the characteristic.
25. What are the advantages of GTO over BJT? 26. What is an MCT? 27. Define turn-on time and turn-off time of thyristor. 28. Define PIV and reverse recovery time of Power diodes. 29. What are the drawbacks of GTO? 30. Draw the turn on characteristics of TRIAC and mark the timings t d, t r and t on 1. (i) Draw the two transistor model of SCR and derive an expression for anode current. (8) (ii) Explain the switching characteristics of SCR (8) 2. Describe the various methods of thyristor turn on. 3. Explain the operation of MOSFET and IGBT 4. (i) Explain the principle of operation and draw the chacteristics of MOSFET. (8) (ii)discuss the different modes of operation of thyristor with the help of its static V-I characteristics. (8) 5. (i) Draw and explain the two transistor model of a SCR. Using this model describe the various mechanisms of turning on a thyristor. (8) (ii)explain the turn off characteristics of a GTO. (8) 6. Compare the following power devices with respect to their advantages and limitations. A) Power MOSFET b)igbt, c)triac d)mct. 7. Explain the protection of power devices in detail. 8. Draw the schematic and equivalent circuit of MCT and explain its operation. 9. Discuss the transfer, output and switching characteristics of power MOSFET. 10. Explain the switching performance of BJT with relevant waveforms indicating clearly the turn-on, turn-off times and their components. Also define the term Safe Operating Area. 11. Describe about any one driver and sunbber circuit for MOSFET 12. Explain the structure, different modes of operation and characteristics of TRIAC 13. Explain the static and switching characteristics of IGBT. UNIT -2 CONVERTERS 1. What is the function of freewheeling diodes in controlled rectifier? 2. What is commutation angle or overlap angle? 3. What are the advantages of six pulse converter?
4. What is meant by commutation? 5. What are the types of commutation? 6. Mention some of the applications of controlled rectifier. 7. What are the different methods of firing circuits for line commutated converter? 8. What are the advantages of three phase converter over single phase converter? 9. What is commutation angle or overlap angle? 10. What are the advantages of six pulse converter? 11. What is meant by natural and forced commutation? 12. What does ac voltage controller mean? 13. What are the applications of ac voltage controllers? 14. What are the advantages and disadvantages of ac voltage controllers? 15. What are the two methods of control in ac voltage controllers? 16. What is the difference between ON-OFF control and phase control? 17. What is meant by cyclo-converter? 18. What is meant by step-up cyclo-converters? 19. What is meant by step down cyclo-converters? 20. What are the types and applications of cyclo-converter? 1. Explain about Rectifiers and specify their applications. 2. Describe using a power circuit and relevant waveforms the working of a single phase full converter with RL load. 3. Write neat sketch and output voltage waveforms explain the working of single phase bridge rectifier. 4. Discuss the operation of single phase half wave rectifier with RE load.also derive its average output voltage equations. 5. Describe the working of single phase fully controlled bridge converter in the rectifying mode. And derive the expressions for average output voltage and RMS output voltage. 6. Describe the working of single phase Dual converter. 7. Describe the working of three phase Dual converter. 8. Derive the expressions for average output voltage and RMS output voltage of single phase semi converter.
9. Describe the working of 3 phase fully controlled bridge converter in the Rectifying mode. And derive the expressions for average output voltage and RMS output voltage. 10. Explain the operation of AC voltage controllers with neat diagram. 11. Explain the operation of single phase AC voltage controller with RL load. 12. Derive the expressions for average output voltage and RMS output voltage of three phase semi converter. 13. Derive the expressions for average output voltage and RMS output voltage of three phase cycloconverter. 14. Derive the expressions for average output voltage and RMS output voltage of single phase cyclo converter. 15. Explain the operation of three phase full converter and also derive the expression for its average output voltage. 16. (i) Explain the effect of source inductance in the operation of single phase fully controlled converter (8) (ii) Describe the working principle of single phase AC voltage controller with circuits and wave forms. (8) UNIT-III INVERTER AND CHOPPER 1. What is meant by dc chopper? 2. What are the advantages and applications of dc chopper? 3. What is meant by step-up and step-down chopper? 4. What is meant by duty-cycle? 5. What are the two types of control strategies? 6. What is meant by TRC? And what are the two types of TRC? 7. What is meant by PWM control in dc chopper? 8. What is meant by inverter? 9. What are the applications of an inverter? 10. What are the main classifications of inverter? 11. Why thyristors are not preferred for inverters? 12. Give two advantages of CSI. 13. What is meant by series inverter? 14. What is meant by parallel inverter? 15. What are the applications of a series inverter? 16. What is meant by McMurray inverter?
17. What are the applications of a CSI? 18. What is meant by PWM control in inverter? 19. What are the advantages of PWM control? 20. What is current source inverter? 21. What is meant by time ratio control in chopper? 22. What is constant frequency control of chopper? 23. What are the advantages of PWM inverter? 24. What are the different techniques of PWM techniques? 1. Describe the operation of series inverter with aid of diagrams. Describe an Expression for output frequency, current and voltages. What are the disadvantages of basic series inverter? 2. Describe the operation of parallel inverter with aid of diagrams. Describe an Expression for output frequency, current and voltages. What are the disadvantages of basic series inverter? 3. State different methods of voltage control inverters. Describe about PWM control in inverter. 4. Describe in detail about the types of chopper. Derive an expression for the average output voltage in terms of input dc voltage & duty cycle 5. Explain the operation of 3 phase bridge inverter for 180 degree mode of operation with aid of relevant phase and line voltage waveforms. 6. Explain the operation of 3 phase bridge inverter for 120 degree mode of operation with aid of relevant phase and line voltage waveforms. 7. Describe the principle of step-up chopper. Derive an expression for the average output voltage in terms of input dc voltage & duty cycle. 8. Describe the principle of current source inverter. Derive an expression for the average output voltage in terms of input dc voltage. 9. Describe the working of four quadrant chopper. 10. Explain the working of current commutated chopper with aid of circuit diagram and necessary waveforms. Derive an expression for its output voltage. 11. Explain the working of voltage commutated chopper with aid of circuit diagram and necessary waveforms. Derive an expression for its output voltage. 12. Draw the power circuit for step down DC chopper and explain its operation for inductive load. What is the role of freewheeling diode in such choppers? 13. Explain the operation of boost and buck boost converter with neat circuit diagrams and waveforms
14. Discuss the functioning of three phase VSI with neat circuit diagrams and waveforms UNIT 4- DC AND AC DRIVES 1. What are the three types of DC drives? 2. Write the basic EMF equation of dc motor. 3. Draw the torque/speed characteristics of dc series motor. 4. Define plugging. 5. What is regenerative braking? 6. What is dynamic braking? 7. Draw the block diagram of modern electric drive. 8. What is the difference between armature and field speed control method? 9. Write the slip equation of induction motor? 10. Define slip. 11. Draw the per phase equivalent circuit of three phase induction motor. 12. Define pull out torque. 13. Write the relation between power and torque of three phase induction motor. 14. Draw the torque/speed characteristics of three phase induction motor. 15. What are the methods used to control the speed of three phase induction motor? 16. What are the advantages of slip power recovery schemes? 17. What is the significance of self controlled synchronous motor drives? 18. Mention the merits of forced commutated ac-dc converters used in dc drives. 19. What are the two important slip power recovery schemes? 20. What are the methods used to control the speed of synchronous motor? 21. Draw the phasor diagram for cylindrical rotor motors. 22. What is the difference between electromagnetic torque and reluctant torque? 1. Give the concepts of electric drive. Give the two methods of speed control normally employed for dc motors. 2. Draw the equivalent circuit of a separately excited dc motor and derive the expressions for motor torque and armature voltage.
3. Describe with appropriate voltage and current wave forms the working of single phase full converter fed drive. 4. Explain briefly the following methods of braking a dc motor Regenerative braking Dynamic braking Plugging 5. Draw the circuit diagram and explain the operation of three-phase, half wave converter drives. 6. Draw and explain the operation of single phase half wave converter drive and also draw the related voltage and current waveforms. 7. Enumerate the various method of speed control of a three phase induction motor when fed through semiconductor devices? 8. Derive the expressions for power developed in a salient pole synchronous motor in terms of excitation voltage, load angle etc. neglect armature resistance. 9. Enumerate the various types of synchronous motor. Derive the expressions for power developed in a cylindrical-rotor synchronous motor in terms of excitation voltage, load angle etc. neglect armature resistance. 10. Explain with relevant circuit diagrams, both types of static scherbius drive for obtaining speeds below as well as above synchronous speed. 11. Describe static Kramer drive for the speed control of a three phase SRIM and show how the steady state torque is not influenced by whether a transformer is used or not. And derive the appropriate expressions to obtain speed-torque characteristics of static Kramer drive. UNIT-5 OTHER APPLICATIONS 1. What is an electronic Timer? What is its use? 2. Mention the advantages of electronic timer over electron tube timer. 3. What are the classifications of electronic timers? 4. What is a digital counter? 5. What is the need of voltage regulators? 6. What is voltage regulation? 7. Mention the types of voltage regulators. 8. What is SMPS? 9. Mention the advantages and disadvantages of SMPS.
10. What is UPS? 11. What are the topologies of UPS? 12. What is high frequency heating? 13. Mention the two types of heating. 14. What is an induction heating? 15. What is Dielectric heating? 16. Mention the advantages and disadvantages of induction heating. 17. Mention some of the applications of induction heating. 18. Compare induction heating and dielectric heating. 19. Name the different topologies of un interrupted power supply. 20. What is offline UPS? 21. What is the necessity of UPS and draw its block diagram. 1. Explain the operation of Zener diode voltage regulator. 2. Explain the operation of transistor series regulator. 3. Draw the block diagram and explain the operation of SMPS which can be employed for low power applications and other for high power applications. 4. Explain in detail about the operation of UPS. 5. Draw and explain the operation of induction heating. 6. Explain in detail about the principle and application of Dielectric heating. 7. Write notes on (i) Electronic timers (ii) Digital Counters 8. Discuss the operation of on line and off line UPS with neat block diagram. 9. With neat circuit diagram explain the operation of switched mode and resonant ac power supply used in UPS. 10. With a neat sketch, explain the working of switched mode power supply.