新型CH5光伏逆变器共模漏电流抑制研究

Research on Common-mode Leakage Current Suppression for a Novel CH5 PV Inverter

漏电流抑制是非隔离型光伏系统需要解决的关键问题。该文首先分析了传统CH4光伏逆变器的工作原理,建立了系统共模回路模型,分析了系统共模特性和漏电流抑制能力。然后提出一种新型CH5光伏并网逆变器,从原理和理论上证明了新拓扑具有抑制漏电流的优点,并提出新型一维空间矢量调制策略改善系统共模漏电流抑制能力,最后在TMS320F28335 DSP+EP4CE10E22C8 FPGA数字控制实验平台上对提出的CH5拓扑和传统CH4拓扑进行了对比实验研究,结果验证了提出方法的有效性。

Leakage current suppression is one of the key technical issues for the transformerless photovoltaic （PV） systems. Firstly, the conventional current source H4 （CH4） PV inverter was investigated in this paper. The operation principle and common mode loop model were analyzed. The common mode feature and leakage current suppression capability were discussed. Secondly, a new current source H5 （CH5） PV inverter topology was proposed. The theoretical analysis was derived to verify the advantages regarding the leakage current reduction. Also, a new one dimension space vector modulation was proposed to improve the common mode feature to reduce the leakage current. Finally, the experiments of both CH4 and proposed CH5 inverters were carried out on the TMS320F28335 DSP ＋ EP4CE10E22C8 FPGA digital control platform. The experimental results verified the effectiveness of the proposed solution.