Abstract：In the traditional non-transformer PV grid-connected inverter systems, the additional AC-side or DC-side bypass switches are usually added into the inverters to solve the problem of the leakage current. However, the additional bypass switches increase the system cost, and also need extra driving circuits leading to complex circuit structure and complicated control. Therefore, a new solution based on the bypass capacitor is proposed to suppress the leakage current. The typical L-filter-based PV inverter is considered. Based on the common-mode model, the bypass capacitor scheme is proposed to reduce the leakage current. The effects of different values of bypass capacitances on the common-mode characteristics are discussed. The proposed scheme can effectively bypass the high frequency component of the common-mode voltage, and keep the parasitic capacitors voltage almost constant. Accordingly, the leakage current can be suppressed in an effective way. Finally, the experimental results verify the effectiveness of the proposed solution.
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2017, Vol. 32 
