Abstract：The single-phase transformerless photovoltaic (PV) system is investigated in this paper. A new single-phase four-switch multilevel inverter is proposed based on the full-bridge topology. Firstly, the operating principle is analyzed. Secondly, the high-frequency common mode model is established. The corresponding output voltage and common mode voltage corresponding to sixteen switching states are derived. Thirdly, two modulation strategies are presented to achieve the five-level output voltage and constant common mode voltage, depending on the different applications. The proposed solution is tested with Matlab. Finally, the experiments are carried out on the digital control platform with TMS320F28335 DSP and XC3S400 FPGA. The experimental results verify the effectiveness of the proposed solution.
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2018, Vol. 33 
