基于中性点电容的三相光伏逆变器漏电流抑制

针对三相非隔离光伏发电并网系统的漏电流问题,提出了一种基于中性点电容的三相三电平逆变器漏电流抑制方法.建立三相三电平光伏逆变器共模模型,分析了漏电流的产生机理和抑制机理.为了抑制寄生电容上共模电压产生的漏电流,用电容将交流侧中性点和直流侧中性点连接起来,形成漏电流的共模LC滤波电路.该滤波电路可有效滤除共模电压的高频分...

Leakage Current Suppression of Three-phase Photovoltaic Inverter Based on Neutral-point Capacitance

Aimed at the leakage current problem in a three-phase transformerless photovoltaic(PV) power generation grid-connected system, a leakage current suppression method for a three-phase three-level inverter based on neutral-point capacitance is proposed. The generation and suppression mechanisms of leakage current are analyzed by establishing a common-mode model of a three-phase three-level PV inverter. To suppress the leakage current generated by the common-mode voltage on the parasitic capacitance, the AC- and DC-side neutral-points are connected by a capacitor to form a leakage current common-mode LC filter circuit, which can effectively filter the high-frequency component of the common-mode voltage and has no influence on the differential-mode loop. Finally, the effectiveness of the proposed method was verified by simulation and experimental results.