非隔离型三相四桥臂光伏逆变器漏电流抑制研究

Leakage Current Reduction for Three-Phase Four-Leg Photovoltaic Inverter

针对非隔离型三相三桥臂光伏逆变器无法有效抑制漏电流的问题,提出基于三相四桥臂拓扑的漏电流解决方案。建立非隔离型三相四桥臂光伏逆变器系统共模模型,分析了影响系统漏电流的主要因素和变量,提出一种基于布尔函数逻辑运算的新型载波调制策略。该调制可以实现共模电压恒定,从而有效抑制漏电流。最后搭建了TMS320F28335DSP+XC3S400FPGA数字控制硬件实验平台,对提出的新型载波调制进行了实验研究,并与传统调制方案进行了对比分析,实验结果验证了提出方案的有效性。

In order to solve the problem of the leakage current in three-phase photovoltaic （PV） inverter systems, a new solution of the leakage current reduction is proposed with the three-phase four-leg PV inverter. The common mode loop model of the transformerless four-leg PV inverter is presented. The effect of different factors and variables on the leakage current is discussed. A new modulation strategy based on Boolean logic function is then proposed to ensure the constant common-mode voltage. And thus the leakage current can be significantly suppressed. Finally the proposed modulation is implemented on the TMS320F28335DSP ＋ XC3S4OOFPGA digital control hardware platform. And the performance is also presented by comparison with the conventional modulation methods. The experiment results verifv the effectiveness of the nronosed modulation strategy.