基于陷波算法实现LCL变流器网侧电流直接控制

A Novel Control Strategy of LCL-VSC Based on Notch Concept

随着并网变流器容量的增大,LCL滤波器的滤波优势得以体现,但与L型滤波器相比,LCL型滤波器存在谐振点,降低了系统的稳定性。常规的无源阻尼和有源阻尼的控制策略虽然能增强系统的稳定性,但会增加系统损耗,或者需要额外的传感器。这里首先比较分析了系统不同变量作为反馈值对LCL变流器的控制性能影响。在不增加额外传感器的基础上,选择最佳的控制对象,得出一种基于陷波器理论的新型有源阻尼算法,实现对网侧电流的稳定控制。并给出了陷波器参数的设计方法,仿真和实验验证了所述方案的有效性。

Although the advantages of the LCL type filter are presented by the increase of the capacitance of the grid-con-nected converter,compared to L type filter,LCL type filter has resonance frequency point,consequently reduce the relia-bility of converter.The general control strategy with passive damp or active damp can improve the stability of the convert-er,but it will bring extra loss,or need more sensor.This paper analyses the infection to LCL converter controller,when us-ing different system variable as feedback.Based on the optimization choice of feedback variable,a novel active damp con-trol strategy without extra sensor is proposed,it use the notch method and achieve the stably control of the grid current.The design method of notch parameter is suggested.The simulation and experimental results verify the effectiveness of the sys-tem design.