Two-stage micro-grid inverter with high-voltage gain for photovoltaic applications

Abstract

This study proposes a new two-stage high voltage gain boost grid-connected inverter for AC-module photovoltaic (PV) system. The proposed system consists of a high-voltage gain switched inductor boost inverter cascaded with a current shaping (CS) circuit followed by an H-bridge inverter as a folded circuit and its switches operate at line frequency. The switched inductor boost converter (SIBC) has one switch operates like a continuous conduction mode. The maximum power of the PV module is achieved through the SIBC circuit whereas the grid connection requirements are accomplished using the CS circuit with the H-bridge inverter. The switch of the CS circuit is controlled with a sine wave modulation control scheme. The main advantages of the new proposed system are high boosting gain, lower switching losses and reduces the ground leakage current as all H-bridge switches operate at the line frequency. A 120 W prototype has been built and experimentally tested. It has been found that experimental results have a good matching with the proposed analysis and simulation results. © The Institution of Engineering and Technology 2013.