基于双PI+重复控制的光伏逆变器谐波抑制策略

A Strategy for Harmonic Suppression of Photovoltaic Inverter Based on Double PI+ Repetitive Control

针对光伏逆变器并网电流谐波较大的问题,首先对三电平逆变器的主电路结构进行了分析,得出了网侧输出电流的数学模型,并分析了该模型下逆变器谐波产生的机理。在分析了传统的PI+重复控制的基础上,针对传统PI与重复控制相互耦合容易导致等效重复控制对象不稳定的问题,提出了一种双PI+重复控制(double proportional integral+repetitive control,DPI+RC)的控制策略。采用PI补偿,在保证了传统PI+重复控制系统跟踪的快速性和准确性前提下,确保了系统的稳定性。最后,通过仿真和试验分析,验证了该控制策略对谐波抑制的有效性和可行性。

In this paper, the main circuit structure of the photovoltaic inverter is analyzed, the mathematical model of the net output current is generated, and the mechanism of harmonic generation of inverter under this model is analyzed.Based on the analysis of traditional PI+ repetitive control, for the problem of the equivalent repetitive control object instability easily caused by the coupling of traditional PI and repetitive control, this paper presents a control strategy of Double Proportional Integral + Repetitive Control(DPI+RC).By using PI compensation, the stability of the system is ensured by ensuring the speed and accuracy of traditional PI+ repetitive control system tracking. Finally, the feasibility of the control strategy for harmonic suppression is verified through simulation and experimental analysis.