CLOSED LOOP PWM INVERTER INDUCTION MOTOR DRIVE

Abstract

The microprocessor implementation of new optimal PWM switching strategies are presented and the special features, characteristics and advantages of various microprocessor configuration are demonstrated. The theoretical and practical development of a new suboptimal PWM switching based on well established regular sampling techniques, is presented. It is shown that this suboptimal PWM strategy closely approximates and exhibits many of the desirable performance characteristics of optimised PWM strategies based on minimised THD. The new suboptimal strategy is based on a well defined modulation process which has the potential for on-line real time microprocessor generation. A new high voltage suboptimal (HVSO) pulse width modulation (PWM) switching strategy is presented which can be used at high fundamental PWM voltages to achieve a smooth, transient free low harmonic distortion, and transition from the PWM to quasi square wave mode