A Novel Phase-Shift Autotransformer with Reduced kVA Capacity in Multi-pulse Rectifier

In this paper a novel phase-shift autotransformer is proposed to reduce the required kVA capacity in multi-pulse rectifier applications with utility interface. The structure and operation principle of proposed autotransformer are presented and analyzed in detail. Design criteria of turn ratio, phase-shift angle and equivalent capacity for the proposed autotransformer is illustrated. It can be shown that the proposed method can significantly lower the kVA rating of transformer to 9.38% of output power. Simulations in Matlab/Simulink and experimental results of a 40kW prototype further validate the proposed concept.