A novel single-stage dual-active bridge based isolated DC-AC converter

This paper presents a single-stage, isolated DC-AC converter topology based on the dual active bridge concept. The proposed topology has the advantages of low device count and high efficiency due to the single-stage power processing structure and zero-voltage-switching (ZVS) operation of the MOSFETs. Double-line-frequency energy buffering can be achieved via the high voltage side dc bus capacitor, resulting in reduction of decoupling capacitance requirement. Thus it can be considered as a suitable candidate for high-efficiency, isolated, single-phase DC-AC converter applications such as PV microinverter. Basic principle of operation of the circuit is described followed by an explanation of the control strategy. Numerical simulation results are presented to validate the approach. Practical evaluation of converter performance is done on a 200 W experimental prototype.