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

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.