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

Abstract

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 microinverters single stage transformer-less topologies are preferred as they offer better power evacuation efficacy. A SEPIC-Ćuk 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.

A Comprehensive Control Strategy for a Push–Pull Microinverter Connected to the Grid

“…In [32], the effects and consequences of the circulating current are analyzed in the transformerless boost microinverter. In [33,34], the consequences of leakage current and leakage inductance in the Sepic-Ćuk microinverter are analyzed. The advantage of using the pull-pull topology is that it eliminates the problems caused by leakage current flowing from the PV panel to ground through parasitic capacitors in non-isolated single-stage microinverters, due to the fact that the topology of the microinverter push-pull uses a transformer in its architecture.…”