An input current waveshaping AC-DC converter for rectifier loads

This paper presents the design and analysis of a new input AC current waveshaping AG-DC converter for cost effective harmonic mitigation under varying loads. The proposed converter consists of a delta-polygon connected autotransformer based twelve-pulse AC-DC converter and a small rating passive shunt filter tuned at 11(th) harmonic frequency. The proposed AC-DC converter eliminates the most dominant 5(th), 7(th) and 11(th) harmonics and reduces higher order harmonics; thereby, resulting in an improved power quality at AC mains. Moreover, the design of the autotransformer is modified to make it suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. To validate the proposed approach, various power quality indices are presented under varying loads. Experimental results obtained on the developed converter are given to validate the model and design of the proposed converter.