基于电流环复合控制的有源电力滤波器

Active power filter based on compound control of current loop

针对有源电力滤波器电流环单纯数字PI控制补偿性能有限,提出基于数字PI控制和数字重复控制的复合控制系统。将PI控制器和重复控制器并联在控制系统电流环的前向通道,共同对系统的输出产生影响,利用数字PI控制改善系统的动态特性,利用重复控制改善系统的稳态跟踪性能。提出电流环PI控制器、重复控制器和复合控制系统的结构,并在同步旋转坐标系下,对其进行控制性能分析,详细推导和分析复合控制系统中重复控制器的设计方法、补偿性能及稳定性。进行三相并联型有源电力滤波器的研制和试验研究,结果证明该控制器在稳态运行时能将电网电流的THD值从30%降到3%,而其动态性能尽管有低通滤波器的影响也仅有半个基波周期(10ms)的延时。理论分析、仿真结果和试验结果均证明所提出的基于数字PI控制和数字重复控制的三相并联型有源电力滤波器复合控制可以兼顾系统动态特性和稳态特性。

As the compensation ability of digital PI control for APF（Active Power Filter） current loop is limited ,a compound control system based on digital PI control and digital repetitive control is proposed. They connect with the forward channel of current loop in parallel and exert influence together on the output of system. The PI controller is used to improve the system dynamic performance and the repetitive controller the static follow- up performance. The structures of PI controller,repetitive controller and compound control system are proposed,their control performance is analyzed in the synchronous revolving coordinates system and the design method,compensation performance and stability of repetitive controller are deduced. A three- phase shunt APF is developed and tested. Results show that,the controller reduces grid current THD from 30 % to 3 % in steady-state operation and has only half fundamental cycle delay （10ms） in dynamic performance under the influence of low-pass filter. Theoretical analysis, simulation and test all prove that,the compound control of three- phase shunt APF gives attention to both steady and dynamic performances.