A Switched-Capacitor Three-Phase AC-AC Converter with Symmetrical Topology

Abstract

In this paper, a three-phase direct ac-ac converter is designed by using switched capacitor (SC) techniques. The proposed ac-ac converter consists of three module blocks which have symmetrical converter topology. Due to the symmetrical converter topology, the proposed ac-ac converter can achieve not only high power efficiency but also high input power factor while keeping the frequencies of the input and output voltages equal. Furthermore, unlike a three-phase auto- transformer, the proposed three-phase ac-ac converter requires no magnetic elements. Therefore, there is a possibility that the proposed ac-ac converter can be replaced as conventional three-phase autotransformers. The operation principle and simulation evaluation are described concerning the proposed ac-ac converter in the case of delta-wye and wye-wye connections. The results of the simulation program with integrated circuit emphasis (SPICE) simulation demonstrate the effectiveness of the proposed ac-ac converter.