Enhancing power factor and efficiency of three phase induction motor drive using single main PWM switch and three auxiliary switches

Abstract

This paper presents a novel economic variable voltage high-frequency PWM direct AC to AC voltage controlled three phase induction motor drive. The drive consists of one main switch and three auxiliary controllable switches with AC freewheeling technique and adjustable dead-band between switches. This scheme would be useful for various Industrial drives for high power fans, pumps and blowers coupled to a three-phase induction motor. The proposed drive reduce the motor current thereby decreases the losses and improves the input power factor simultaneously with the reduced number of controllable switches as compared to conventionally used VVVF drive.