Novel Power Converter for Protecting Three-phase AC Power Capacitors

Abstract

A novel power converter for protecting three-phase AC power capacitors is proposed. The salient point of this power converter is that the power converter is configured by a two arms bridge structure without split capacitors. Two of the three-phase AC power capacitors are serially connected via filter inductor set to two AC terminals of power electronic switch set, and another of the three-phase AC power capacitors is connected via filter inductor set to the negative DC terminal of power electronic switch set through no power electronic switches. The power converter acts as virtual harmonic resistors to be inserted into the AC power capacitors. Hence, the power converter, acting as the virtual harmonic resistors, can damp the harmonic resonance and avoid the harmonic current injection of AC power capacitors. Hence, the proposed method can effectively protect the power capacitor from harmonic damage. The proposed power converter has the advantage that the number of power electronic switches is reduced. A prototype is developed and tested to verify the performance of the proposed power converter. Experimental results show that the proposed power converter has the expected performance.