INTRODUCTION TO ELECTRIC DRIVES

Thyristor Principles and characteristics Gate triggering circuits. Phase Controlled Rectifiers Phase angle control, Single-phase half-wave controlled rectifier (One quadrant), Single-phase full-wave controlled rectifier (Two quadrant converters), Performance factors of line-commutated converters, The performance measures of two-pulse converters, Three phase controlled converters. Inverters : Thyristor inverter classification, Series inverters, Parallel inverter, Three-phase bridge inverters, Three-phase bridge inverter with input-circuit commutation. Choppers Principle of chopper operation, Control strategies, Step-up/down chopper, Jones chopper. Cycloconverters : The basic principle of operation, Single-phase to single-phase cycloconverter, Three-phase half-wave cycloconverters, Cycloconverter circuits for three-phase output. Control of D.C. Drives Basic machine equations, Breaking modes, Schemes for D.C. motor speed control, Single-phase separately excited drives, Braking operation of rectifier controlled separately excited motor, Single-phase separately excited drives, Power factor improvement, Three-phase separately excited drives, D.C. chopper drives. Control of A.C. Drives Basic principle of operation, Squirrel-cage rotor design, Speed control of induction motors, Stator voltage control, Variable frequency control, Rotor resistance control, Slip power recovery scheme, Synchronous motor drives.