Three-phase Transformerless PV Inverter with Reconfigurable LCL Filter

In this paper, a three-phase transformerless photovoltaic (PV) inverter with a reconfigurable LCL filter is proposed. The reconfigurable filter constructs LCL filter between the converter and the grid with only three inductors which leads to magnetic components reduction by half compared to a conventional LCL filter. Moreover, the reconfigurable filter at high frequencies clamps the common mode (CM) voltage to Neutral and suppresses the leakage current. Therefore, the proposed topology is able to inject high quality grid current with minimum magnetic components and limit the leakage current to meet international standards. The principle of operation is explained by the equivalent circuits. The proposed topology is verified and compared by simulation and experimental results which agree with the theoretical concept.