Harmonic mitigation in ac-dc converters for vector controlled induction motor drives

This paper deals with autotransformer-based multipulse ac-dc converters with reduced magnetics feeding vector controlled induction motor drives for improving the power quality at the point of common coupling. The proposed 12-pulse ac-dc converter-based harmonic mitigator consists of an autotransformer alongwith a passive shunt filter tuned for 11th harmonic frequency. This results in the elimination of 5th, 7th, and 11th harmonic currents. Similarly, the proposed 18-pulse ac-dc converterbased harmonic mitigator eliminates the 5th, 7th, 11th, 13th, and 17th harmonic currents, thereby improving the power quality at ac mains. The experimentation is carried out on the developed prototype of autotransformers-based ac-dc converters. Different power quality indexes of the proposed 12-pulse and 18-pulse ac-dc converters are obtained from simulation and verified from experimental results.