Control of Three Phase to High Frequency Single Phase Matrix Converter Capable of High Power Factor Operation and Soft Switching

Abstract

An isolated AC/DC converter using a matrix converter (MC), which is a direct AC/AC converter, can be realized with a small size, high efficiency, and long life. Conventional MC control methods require the output frequency to be much lower than the switching frequency. Therefore, these control methods result in large galvanic transformers. This paper proposes an MC control method for the isolated AC/DC converter with the output frequency equal to the switching frequency, which can downsize the transformer. Furthermore, by controlling the instantaneous reactive power, a sinusoidal input current of a unity power factor is realized. Soft switching technology is used to suppress the switching losses. However, it is necessary to reduce the output power factor for soft switching. In this paper, the relationship between soft switching and the output power factor is clarified. The MC achieves the maximum output power factor and soft switching by frequency control using an LC resonant circuit. The effectiveness of the control method was evaluated experimentally.