A Single-Phase Single-Stage Buck-Boost AC-AC with Both In-Phase and Out-of-Phase Voltage Operations and No Commutation Problem

The ac-ac converters with bipolar voltage gain are desired for utility voltage compensation. In this paper, a singlephase buck-boost ac-ac converter is proposed with versatile operating modes and bipolar voltage gain capability. It consists of six bidirectional voltage blocking switches and an inductor, apart from input/ output filtering capacitors. The key features include no shoot-through or commutation problem, no MOSFET body diode conduction, and a common ground between input and output. The proposed converter can provide both in-phase and 180 degree outof- phase output voltages with buck-boost operations. Therefore, it has the potentional to compensate both voltage sag and swell when used as dynamic voltage restorer (DVR). The detail analysis of the proposed converter is provided followed by the experimental results.