Leakage current reduction of three-phase Z-source three-level four-leg inverter for transformerless PV system

A new modulation strategy of Z-source three-level four-leg inverter is proposed in this paper. Firstly, the operation principle is analyzed, and the influence factors, related to the common mode voltage and leakage current of Z source three-phase three-level four leg inverter, are discussed. Secondly, a new modulation strategy based on the double-carrier modulation is proposed. The proposed new method can achieve the constant common mode voltage, so the leakage current can be well attenuated. Finally, the proposed solution is carried out on the TI (Texas Instruments) TMS320F28335 DSP + Xilinx XC3400 FPGA digital control hardware platform. The experimental results verify the effectiveness of the proposed solution. © 2020, Solar Energy Periodical Office Co., Ltd. All right reserved.