Evaluation of Transformerless Inverters for Single Phase Photovoltaic Systems

Abstract: The transformerless inverter topologies have gained more attention in photovoltaic generation system since they feature high efficiency and low cost. Unfortunately, it has problems on the galvanic isolation between photovoltaic systems to the grid, which leads to high leakage current. So in order to meet the safety requirement, leakage current must be tackled carefully in the transformerless inverters. In order to avoid the leakage current, various transformerless inverters have been proposed using different topologies to keep the common mode voltage constant. This paper focuses on the latest development of the inverters for the photovoltaic grid. Their performances are compared and analyzed.

Keywords: photovoltaic systems, leakage current, transformerless inverters, parasitic capacitance, common mode voltage.