LCL滤波单相光伏并网逆变器Quasi-PR控制策略

Quasi-PR Control Strategy for Single-phase Photovoltaic Grid-connected Inverter with LCL Filter

针对采用传统PI控制器的LCL滤波单相光伏并网逆变器在跟踪并网交流信号时存在静差的问题,在并网电流Quasi-PR单闭环控制的基础上,增加1个电容电流内环,从而构成双闭环控制结构,以提高系统抗扰能力,抑制振荡;通过Quasi-PR实现外环并网电流无静差控制.在系统建模和分析的基础上设计参数,利用MATLAB软件进行仿真分析,通过搭建的试验系统加以验证.结果表明:在此控制策略下,获得的并网电流畸变率小,实现了并网电流的无静差跟踪,系统输出波形满足入网要求.

Aiming at the static difference of single-phase photovoltaic grid-connected inverter with LCL filter andtraditional PI controller in tracking grid-connected AC signal,on the basis of Quasi-PR single loop control of gridconnected current,a capacitor current inner loop is added to form a double closed loop control structure,whichimproves the anti-disturbance ability and suppresses the oscillation of the system,realizes external loop-connectedcurrent without static control through Quasi-PR. Based on the system modeling and analysis,the parameter designwas carried out. The simulation analysis was carried out by using MATLAB software and verified by building testsystem. The results show that the obtained grid-connected current distortion rate is low under this control strategy,and the grid-connected current has no static tracking,and the system output waveform meets the requirements ofthe network.