Low harmonic 12-pulse rectifier with a circulating current shaping circuit

Abstract

This paper proposes a four-star 12-pulse diode rectifier with a circulating current shaping circuit (CCSC)on the DC side to decrease the input current harmonics effectively. The type of circulating current that can eliminatethe input current harmonics is analysed and its waveform parameters are derived. The effects of triangular circulatingcurrent on the harmonics of the input current are analysed, and the harmonic suppression mechanism of the triangularcirculating current is revealed. This scheme has excellent harmonic suppression capability, and the capacity of CCSC isonly 2.35% of output power of the 12-pulse rectifier. Thus, this scheme is cost effective for high power applications. Theexperimental results confirm the theoretical analysis and near sinusoidal input current is obtained.