A Single-Phase Grid-Connected Boost/Buck–Boost-Derived Solar PV Micro-Inverter Topology Having Power Decoupling Capability

Abstract

A boost/buck–boost-derived solar photovoltaic (PV) micro-inverter suitable for interfacing a 35 V 220 W PV module to a 220 V single-phase ac grid is proposed in this article. It uses only six switches, of which two switches operate at high frequency (HF), two at line frequency (LF), and the remaining two switches at HF during either positive half cycle (PHC) or negative half cycle (NHC) of the grid voltage. To achieve high gain and negligible turn on losses for the HF switches, the micro-inverter is operated in discontinuous mode of conduction for all possible operating conditions. The negative terminal of the PV module is directly connected to the grid neutral, and hence the magnitude of leakage flow is zero. The instantaneous power mismatch between the dc side and the ac side is addressed by achieving inherent power decoupling in the proposed topology without incorporating any additional active power decoupling circuit (APDC). The detailed analyses of the proposed micro-inverter are carried out. A 220 W laboratory prototype of the proposed micro-inverter is fabricated, and experimental studies are carried out in detail to confirm the viability of the proposed scheme.