Microprocessor based speed control of a chopper-fed d.c. drive
The thesis is concerned with microprocessor-based control of a d.c. drive system using armature voltage control technique with a separately-excited, chopper-fed d.c. motor. The chopper circuit has a full-bridge configuration employing gate-turn-off (GTO) thyristors, and. is capable of four-quadrant operation, making the drive both reversible and regenerative. The control of motor speed is achieved by a completely digital technique, which does not require any analog-to-digital or digital-to-analog converters. A microcomputer, specially designed and built, generates the triggering signals for the GTO's by using the unipolar switching strategy, which is accomplished totally by software using look-up tables.