PULSE DOUBLING IN AC-DC CONVERTER BASED ON ZIGZAG AUTO-CONNECTED TRANSFORMER FOR HARMONIC MITIGATION

摘要

In this paper, a low kilo-volt-ampere rating modified zigzag autotransformer based 12-pulse ac-dc converter feeding vector controlled induction motor drive is designed, modeled and simulated. DC ripple reinjection technique is adopted to further improve performance of the converter. Detailed design procedures of the modified autotransformer and double-tapped interphase reactor are given. Moreover, a harmonic blocking transformer is used to investigate performance of the scheme under amplitude unbalance and phase unbalance of the three phase utility voltage condition. Simulation results confirm that the proposed system is capable of eliminating up to 11th harmonics in the ac mains current, and the power factor is also improved to near unity under varying loads. A harmonic blocking transformer is able to mitigate extra harmonic components under unbalanced utility voltages. In addition, various power quality indices are presented to compare the performance of four different converter topologies.