Micro Inverter Grid Connected for PV Application Based on SEPIC Differential Inverter

Document Type : Original research articles


1 Electrical Engineering Department, Faculty of Engineering, King Khalid University, Abha 61411, Saudi Arabia

2 Department of Electrical Engineering, Faculty of engineering, University of South Valley, Qena, Egypt

3 Electrical Engineering Department, Faculty of Engineering, Aswan University, Aswan 81528, Egypt


The problem of shading in photovoltaic systems has occupied a large part of the researchers' interests, and for this reason, the Micro-inverter (MI) is used as the solution, and the idea of manufacturing them depends on installing a small inverter with a low capacity to a small group of PV cells that agree with this rating. In addition to the interest in efficiency in the case of a connection in the standalone systems or grid electrical network.
A traditional inverter was used, accompanied by a large low-frequency transformer to connect to the grid, and this led to higher costs and volume, then the idea of using different types of choppers appeared as a first stage to boost or buck the voltage, but the second stage beside the inverter stage led to higher costs, so the use of a single stage was the best solution. In addition, using MI with differential mode contributes to obtaining many advantages such as fewer passive elements (inductors and capacitors). This results in the reduced total cost and improved reliability. Among differential topologies of the AC inverters, a Single-Ended Primary-Inductor Converter (SEPIC) has been selected. This inverter was chosen because of its advantages, including the possibility of working in the boost or buck mode, and also a high-frequency pulse switching transformer can be used to act as an isolated step up/down the voltage in PV systems. The theory of differential SEPIC has been validated by PSIM software. The results will be compared with mathematical analysis.