Photovoltaic microinverter using single-stage isolated high-frequency link series resonant topology

Abstract

In this paper, PhotoVoltaic (PV) microinverter using a single-stage high-frequency ac link series resonant topology is proposed. The inverter has two active bridges, one at the front-end of PV module and the other at the output or utility side. The active bridges are interfaced through a series resonant tank and a high frequency transformer. A novel phase-shift modulation technique to regulate the current into utility is proposed. Steady-state analysis using sinusoidal approximation is presented to determine the magnitude of output current into utility. Soft-switching operation is ensured in all switches in the converter due to resonant nature of the circuit. The inverter has advantages of minimal power conversion stages, high-switching frequency operation and low switching losses and hence ideally suited for low power module integrated applications.