DESIGN OF A THREE-PHASE SWITCHED-CAPACITOR AC-AC CONVERTER WITH SYMMETRICAL TOPOLOGY

摘要

In this paper a novel three-phase direct ac-ac converter is proposed in order to offer sinusoidal three-phase voltages. To achieve light weight and small size, the proposed ac-ac converter is designed by switched-capacitor (SC) techniques. While keeping the frequencies of the input and output voltages equal, the proposed converter provides stepped-up or stepped-down voltages to output loads. Unlike conventional SC ac-ac converters, the proposed converter has symmetrical topology without flying capacitors. By reducing the number of capacitors, the proposed ac-ac converter can improve power efficiency as well as input power factor from conventional converters. In the case of delta-wye, delta-delta, wye-delta and wye-wye connections, the operation principle, qualitative analysis and simulation evaluation are described in order to clarify the characteristics of the proposed converter. The results of the simulation program with integrated circuit emphasis (SPICE) simulation demonstrate the effectiveness of the proposed ac-ac converter.