A Novel SEPIC-Ćuk Based High Gain Solar Micro-Inverter for Grid Integration

Solar micro-inverters are becoming increasingly popular as they are modular, and they posses the capability of extracting maximum available power from the individual photovoltaic (PV) modules of a solar array. For realizing micro-inverters single stage transformer-less topologies are preferred as they offer better power evacuation efficacy. A SEPIC-\'Cuk based transformer-less micro-inverter, having only one high frequency switch and four line frequency switches, is proposed in this paper. The proposed converter can be employed to interface a 35 V PV module to a 220 V single phase ac grid. As a very high gain is required to be achieved for the converter, it is made to operate in discontinuous conduction mode (DCM) for all possible operating conditions. Since the ground of the each PV modules is connected to the ground of the utility, there is no possibility of leakage current flow between the module and the utility. Detailed simulation studies are carried out to ascertain the efficacy of the proposed micro-inverter. A laboratory prototype of the inverter is fabricated, and detailed experimental studies are carried out to confirm the viability of the proposed scheme.