Control strategy for a three-phase to single-phase power converter using an active buffer with a small capacitor

A novel three-to-single-phase power converter that allows for smaller smoothing capacitors in the DC link is proposed. Large smoothing capacitors are conventionally required in such converters to absorb power ripple at twice the frequency of the single phase AC. The proposed topology consists of an indirect matrix converter and an active snubber to absorb the power ripple, and does not require a reactor or large smoothing capacitors. In this paper, the fundamental operation of the proposed converter is confirmed through simulations and experiments. The experimental results indicate that for a 1 kW-class prototype circuit, the power ripple at twice the frequency of the power supply can be adequately suppressed using a buffer capacitor of only 50 muF. Moreover, the single-phase power factor of over 99% and good waveforms for input and output current.