An approach to realize higher power PWM AC controller

PWM controlled AC controllers exhibit difficulties in the commutation of inductive load current from one bidirectional switch to another due to finite switch on/off times. A four step switching strategy for repeated on/off operation of bidirectional switches in an AC controller is proposed. The approach permits safe transition of inductive load current at all power factors from one bidirectional switch to another, even in the presence of source side stray inductance. Results from an experimental prototype AC controller coupled to an inductive load are discussed