Soft-switching active-clamp flyback microinverter for PV applications

This paper presents an active-clamp flyback microinverter for grid connected photovoltaic (PV) ac module system. The active-clamp circuit achieves the soft switching by allowing a negative current that discharges the output capacitor of the primary switch and zero voltage switching (ZVS) turn on is achieved. The active-clamp switch is also operated in ZVS. Therefore the switching losses of the high frequency primary switches are negligible. The galvanic isolation provided by the high frequency flyback converter and the single stage operation of the microinverter improve the reliability and efficiency of the system. The simulation of the proposed scheme has been done and a 250 W prototype has been realized to verify in real time operation.