Fundamentals of Power Electronics

Week 1

Power electronic devices

Power transistor: construction, working principle, V-I characteristics and uses.

Week 2

IGBT: Construction, working principle, V-I characteristics and uses. Concept of single electron transistor (SET) - aspects of Nano- technology.

Week 3

SCR: construction, two transistor analogy, types, working and characteristics. SCR mounting and cooling.

Week 4

Types of Thyristors: SCR, LASCR, SCS, GTO, UJT, PUT, DIAC and TRIAC

Thyristor family devices: symbol, construction, operating principle and V-I characteristics.

Week 5

Protection circuits: over-voltage, over-current, Snubber, Crowbar

Week 6

SCR Turn-On methods: High Voltage thermal triggering, Illumination triggering, dv/dt triggering, Gate triggering. Gate trigger circuits – Resistance and Resistance-Capacitance circuits.

Week 7

SCR triggering using UJT, PUT: Relaxation Oscillator and Synchronized UJT circuit. Pulse transformer and opto-coupler based triggering.

Week 8

SCR Turn-Off methods: Class A- Series resonant commutation circuit, Class B-Shunt Resonant commutation circuit, Class C-Complimentary Symmetry commutation circuit,

Week 9

Class D –Auxiliary commutation, Class E-External pulse commutation, Class F- Line or natural commutation.

Week 10

Phase control: firing angle, conduction angle. Single phase half controlled, full controlled and midpoint-controlled rectifier with R, RL load: Circuit diagram, working, input- output waveforms, equations for DC output and effect of freewheeling diode.

Week 11

Different configurations of bridge-controlled rectifiers: Full bridge, half bridge with common anode, common cathode, SCRs in one arm and diodes in another arm.

Week 12

Applications: Burglar’s alarm system, Battery charger using SCR, Emergency light system, Temperature controller using SCR and; Illumination control / fan speed control TRIAC.

Week 13

SMPS. UPS: Offline and Online; SCR based AC and DC circuit breakers.