AC-AC Conversion with Improved Power factor for Efficient Control of Induction Motor Drive

This paper present proposed scheme of AC-AC drive for speed control of Induction Motor. The technique proposed gives leading input power factor. The devices are turned on at zero crossing and turned off at desired instant in every half cycle. In this scheme the drive can operate in entire range of controllable speed and torque unlike conventional phase angle control scheme. The additional advantage in this method is that supply current from AC source becomes leading. The triggering technique of Power electronic devices is opposite to that of firing angle control. The motor voltage is controllable in the entire range from zero to full voltage. The proposed scheme is very useful for various Industrial Applications like Fans, blowers, pumps, Paper mills, textile mills, rolling mills and many more.