Highly efficient flyback microinverter for grid-connected rooftop PV system

This paper proposes a high efficiency DC-DC flyback converter with a resonant full-bridge inverter to use in PV systems. The flyback converter is composed of a resonant active-clamp circuit that limits the voltage stress and provides zero voltage switching (ZVS) turn-on and turn-off of the power switches. Therefore, the switching losses of the high frequency primary switches are negligible. A resonant full-bridge inverter with ZVS of the high frequency switches is adopted to make the overall efficiency high. Moreover, using a film capacitor in the DC link for the power decoupling, the lifespan of the microinverter is increased. A 250 W prototype of the proposed microinverter has been implemented and the performance is analyzed with different loading condition. The feasibility analysis of the proposed topology for the PV modules in different weather condition confirms the superiority of the proposed microinverter for rooftop PV system compared with the existing topologies.