A new method using two triacs for control of single-phase induction motor

Among the conventional methods there is no method by which single-phase induction motors can be started, sped-controlled and reversed. The paper develops a new method for controlling single-phase induction motors with two symmetrical stator windings by placing two bidirectional solid-state switches (triacs), one in series with the main winding and the other with the auxiliary winding. Such a connection will perform all the required jobs namely: starting, speed control and reversing the direction of rotation. A motor representation in the d, q, 0 reference fram is presented. A state-space mathematical model has been developed to describe the system taking care of the discontinuities introduced by the triacs. Computer results for transient and steady-state conditions are presented. Also, experimental verification has been done.