A Novel Single-Phase Transformerless Inverter for Grid-Connected Photovoltaic Systems

Eliminating the leakage current is one of the most important issues for transformerless inverters in grid-connected photovoltaic system applications, where the technical challenge is how to keep the system common-mode voltage constant to reduce the leakage current. A novel single-phase three-level topology for transformerless photovoltaic systems is presented in this paper. Compared with the conventional H-bridge topology, it only needs two additional asymmetrically distributed switches, and the system common-mode voltage can be kept constant with a simple modulation scheme. Test results verify the theoretical analysis and the feasibility of the proposed topology.