Comparison of power quality indices and apparent power (kVA) ratings in different autotransformer-based 30-pulse AC–DC converters

Abstract

Three-phase multipulse AC–DC converters (MPC) are developed for improving power quality to reduce harmonics in ac mains and ripples in dc output. This study, based on technical and economic factors, compares different autotransformer-based 30-pulse AC–DC converters. In this
paper, the comparison of two topologies of autotransformer-based 30-pulse AC–DC converter has been presented. In topology A, three-phase AC voltages are given to the autotransformer, which produces five sets of three-phase voltage and, in topology B, three-phase AC voltages are given to the autotransformer, which produces three sets of five-phase voltages of same magnitude and distributed in time through phase shifts of 12? . Topology A included polygon, hexagon, star, fork, and T-connected autotransformer-based 30-pulse AC–DC converters, and topology B Included polygon, and T-connected autotransformer-based 30-pulse AC–DC converters. These converters have been implemented and simulation using Matlab/Simulink software for similar ratings under different load conditions has been performed. A set of power-quality indices on input ac mains and on a dc bus for a DTCIMD fed from different 30-pulse AC–DC converters is given to compare their performance. Economic comparison of 30 pulse AC–DC converters is based on the apparent power (kVA) ratings of the different autotransformer for 30 pulse AC–DC converters.