Low-cost photovoltaic microinverter with ultra-wide MPPT voltage range

This paper presents a novel low-cost photovoltaic (PV) microinverter with an ultra-wide MPPT voltage range. This approach is based on the two-stage energy conversion where the front-end boost half-bridge DC-DC converter is used to step up the fluctuating PV voltage to a stabilized high DC voltage, which is next transformed to a grid compliant AC voltage by the grid-tied inverter. The operation principle of the microinverter is explained by the help of the steady-state analysis. To verify theoretical assumptions and evaluate the performance of the proposed concept, a 250 W experimental prototype of a photovoltaic microinverter was assembled and tested. Finally, its shade-tolerant operation is demonstrated with the partially shaded 60-cell Si PV module.