Passive Harmonic Reduction for 12-Pulse Rectifier Using two Kinds of Unconventional Multi-tap Inter-Phase Reactors

A passive harmonic reduction scheme using two kinds of unconventional multi-tap inter-phase reactors is proposed to reduce the input current harmonics of the 12pulse rectifier effectively, and a novel multi-pulse rectifier with an approximately sinusoidal input current is obtained. The proposed passive harmonic reduction circuit (PHRC) is mounted on the DC side of the rectifier and comprises four auxiliary diodes, a three-tap inter-phase reactor and a four-tap inter-phase reactor. The four auxiliary diodes in the PHRC alternate conduction which increases the number of steps of the input current from 12 to 30 and effectively suppresses the input current harmonics. The proposed scheme does not require the use of any active devices. Thus, the proposed scheme has the advantages of simple circuit structure, cost-effective and high reliability. A 20 kW simulation prototype is built, and the simulation results verify the accuracy and effectiveness of the theoretical analysis.