1. Thyrlstors and their characteristics :
Introduction to thyristor family V-I characteristics of SCR, SUS, PUT, SCS, GTO, LASCR, DIAC and TRIAC. Principle
of operation of SCR. Two transistor analogy. Turn on methods of a thyristor Switching charactgeristics of thyristors
during tum-on and turn-off. Gate characteristics. Firing of thyristors. Gate triggering circuits. Series and parallel,
operation of SCRs and their triggering circuits. Thyristor specifications; such as latching current and bolding current,
dv/dt and di/dt, PTV etc. Protection of SCR from over voltage and over current. Snubber circuits. Power dissipation.
2. Thyristor commutation techniques :
Load commutation (Class A), Resonant-Pulse commutation (class B), impulse commutation (class D), Line
commutation (class F).
3. Phase controlled techniques :
Introduction to phase angle control. Single phase half wave controlled rectifiers. Single phase half controlled and full
controlled bridge rectifiers. Three phase full controlled bridge rectifiers. Effect of resistive, inductive and resistive cum
inductive loads. Basic circuit and principle of operation of Dual Converter, circulating current mode and non-circulating
current mode of operation. Applications of rectifiers and dual converters to speed control of DC motor drives.
4. Choppers
Introduction and principle of chopper operations. Control strategies, two quadrant chopper, Four quadrant
chopper. Regenerative chopper. Steady state time domain analysis of type A-chopper, voltage commutated
chopper or classical Jones chopper.
5. Cycloconverters
Basic circuit and operation of single phase cycloconverter. Single phase bridge cycloconverter. Three phase
to single phase to single phase cycloconverter. Advantages disadvantages of cycloconverters.
6. Inverters :
Introduction to inverter. Operating principle and already state analysis of single phase, voltage
source, bridge inverter. Modified Mcmurray half-bridge and full bridge inverter. Three phase bridge
inverter. Voltage control (PWM control etc.) and reduction of harmonics in the inverter output
voltage. Series inverter.