Transformerless Six-Switch (H6)-based Single-Phase Inverter for Grid-Connected Photovoltaic System With Reducd Leakage Current

Abstract

Advancements of power electronic devices and photovoltaic (PV) power systems, there has been an increasing interest in transformerless grid-connected PV inverters due to the benefits of lower cost, smaller volume and higher efficiency compared to the one with the transformer. However, transformerless inverters with conventional topologies suffer from leakage current problem which needs to be handled carefully. In order to overcome the conduction loss and leakage current problem associated with conventional transformerless inverters, a new transformerless H6 (6-switch-based) inverter topology is proposed in this paper that can maintain constant common mode (CM) voltage while reduce or eliminates the leakage current problem. The proposed inverter topology is simulated using MATLAB/Simulink software to validate the accuracy of the proposed system. The effectiveness of the proposed topology is verified through the comparative results of CM voltage, CM leakage current and conduction loss of the proposed topology with the conventional H6-I, H6-II and H5 topologies. Finally, to validate the proposed topology, a laboratory prototype is also built and tested. The experimental results validate the theoretical analysis and simulation results.