CONTROL OF SINGLE-PHASE INDUCTION-MOTOR USING FORCED-COMMUTATED ELECTRONIC SWITCHES

Single phase induction motors require assistant methods for starting, speed-control and reversing direction of rotation. The available metho ds suffer from many drawbacks. Most of these drawbacks are due to use of mechanical switches in addition to other expensive electrical equip ment. This paper suggests a nonconventional versatile method which rea lizes all the motor requirements. The method uses two forced-commutate d electronic switches to feed a single-phase motor which has two symme trical stater windings. By this circuit, the motor could produce a hig h starting torque. Also the speed could be controlled and the directio n could be reversed. A state space mathematical model has been develop ed for the motor and its solid state feeding converter. With the aid o f the model, the system has been simulated by a developed computer pro gram. Transient starting characteristics have been computed. Also, ste ady state speed control characteristics have been obtained for differe nt control strategies. The performance of the motor has been compared with other conventional control methods, and with a method which uses naturally commutated electronic switches.