分布式光伏并网发电系统的高频环流抑制

High-Frequency Circulating Current Elimination for Distributed Photovoltaic Grid-Connected Generation System

针对分布式光伏并网发电系统的高频环流问题,建立了高频环流的等效模型,提出了有效抑制方法。分析Ⅰ、Ⅱ类高频环流的导纳;采用LCL滤波器的并联方案,选择合理大小的电感比。通过2台10 k W的光伏逆变器构成的分布式试验平台,证明了高频环流模型分析和抑制方法的正确性。

According to the problem that high-frequency circulating current exists in the distributed photovoltaic grid-connected generation system,the equivalent model of the high-frequency circulating current and the effictive suppression method were proposed. The high-frequency circulating current is divided into two types,namely,types Ⅰ and Ⅱ,according to different loops. The admittance of types Ⅰ and Ⅱ circulating current was analyzed,and the conclusion was made that type Ⅰ circulating current is much larger than type Ⅱ. Then,the parallel scheme with LCL filter was used,and the inductance ratio was reasonably designed to reduce the highfrequency circulating current effectively. A distributed photovoltaic grid-connected generation system rated 10 k W was built. The experimental results demonstrate the correctness of the model analysis and reduction methods of the high-frequency circulating current.