Improvement of driver efficiency for the single-phase motor

The electrical fan, based on the induction motor, operate with very low efficiency on the high slip, when the speed control is used by the series inductors. In order to improve the efficiency, inverter benefit with Pulse Width Modulation (PWM) methods included the unipolar PWM and the bipolar PWM is discussed. The new type two-phase induction motor speed control is first designed and compared with the conventional method by using the two-phase theory. The voltage source inverter with three legs provides two phase voltages, vd and vq, to the main and the aux winding in the single-phase induction motor.