PWM AC chopper control schemes for energy saving of single-phase induction motors

This paper presents control schemes for energy saving of a capacitor start and run type single-phase induction motor using a PWM AC Chopper to adjust the appropriate motor voltage under various load levels. MATLAB/Simulink is used for the simulation. The main winding stator current is used to feedback for minus with the appropriate current obtained from the multiple of the auxiliary winding stator current and the appropriate constant. Then, the error is sent to a PI Controller. The output of the PI controller will be compared with a carrier to generate PWM signals for controlling all bidirectional switches of the single-phase AC chopper. With the proposed scheme under any motor load level, the motor will always operate at the rated speed, which allows for high efficiency and energy saving. The motor energy saving is 43.97%, particularly at light load.