三相LCL并网逆变器自带低通滤波功能的复合控制方法

Composite Control Method for Three-phase LCL Grid-connected Inverter with Low-pass Filtering Function

针对三相LCL型并网逆变器并网电流存在谐波污染问题,提出一种自带低通滤波功能的复合控制方案。在传统重复控制的内模中建立谐振衰减控制器,改善了重复控制对高频谐波抑制能力不佳的问题,不仅省去了低通滤波器的设计环节,简化了控制结构,同时提升了系统的整体稳态性能。将比例控制与带有谐振衰减控制器的重复控制并联组成自带低通滤波功能的复合控制,提高了系统负载突变时的动态补偿能力。最后提出了对自带低通滤波功能重复控制器参数的设计方案,理论分析和仿真结果验证了该控制方案的有效性。

Aimed at the problem of harmonic pollution in the grid-connected current of a three-phase LCL grid-connected inverter,a composite control scheme with a low-pass filtering function is proposed.A resonant attenuation controller is built in theinternal model under the traditional repetitive control,which solves the problem of poor suppression of high-frequency harmonic by repetitive control.As a result,the design of the low-pass filter is omitted,and the control structure is simplified.Meanwhile,the overall steady-state performance of the system is improved.The proportional control and the repetitive control with the resonant attenuation controller are combined in parallel to form a composite control with a low-pass filtering function,which improves the dynamic compensation capability when the change in system load is abrupt.A design scheme forthe parameters of the repetitive controller with alow-pass filtering function is put forward,and the oretical analysis and simulation results verify the effectiveness of the proposed control scheme.