Autotransformer Based Nine-Phase AC-DC Converter for Harmonic Mitigation in Induction Motor drives

This paper deals with an autotransformer based improved power quality nine-phase AC-DC converter feeding vector controlled induction motor drives (VCIMD´s). The design of the proposed autotransformer is presented along with the necessary modifications required for making it suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. The proposed AC-DC converter is found capable of improving the power quality indices in a wide operating range of the drive. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed AC-DC converter. A set of power quality indices on input AC mains and on DC bus for a VCIMD fed from various AC-DC converters are presented to compare their performance