内置重复控制器无差拍控制在有源滤波器中的应用

Application of Deadbeat Control with Plug-in Repetitive Controller in Active Power Filter

有源滤波器补偿电流跟踪控制要求具备较高的稳态精度和良好的动态性能。本文将无差拍控制和重复控制结合,利用二者优势,实现四桥臂有源滤波器电流环控制。依据四桥臂有源滤波器数学模型,推导了应用于该滤波系统的无差拍控制算法;通过内置重复控制器,改善无差拍控制的缺陷,消除周期性稳态误差,通过设置低通滤波器及补偿器改善系统的稳定性;分析了各环节的设计方法。在四桥臂有源电力滤波器实验平台上对所提控制策略进行了实验验证,滤波后三相电源电流畸变率分别由16.9%、26.7%、27%降至2.7%、2.7%、2.8%,中线电流有效值由1.58A降至0.17A。该结果表明,本文提出的内置重复控制的无差拍控制策略有效地抑制了谐波,较好地解决了三相不平衡问题,从而证明了此控制策略的有效性。

The compensation current tracking control for active power filter（APF） requires higher steady precision and better dynamic performance. In this paper, the deadbeat control is combined with repetitive control and advantages of the two controllers are utilized to realize the current loop control of the four-leg APF. Based on the four-leg APF mathematical model, the deadbeat control algorithm applied in the filter system is deduced. In order to avoid the defects of deadbeat control, a repetitive controller is introduced to eliminate periodic steady-state error. The system stability is improved by setting a low-pass filter and a compensator. The design method of each part is analyzed. The experiment on a four-leg APF phototype was carried out to verify the proposed control strategy. The total harmonic distrotion（THD） values of three phase source currents after filtering reduce to 2.7%, 2.7%, and 2.8% from 16.9%, 27%, 26.7% respectively, and the root mean square value（rms） of the neutral current dropes to 0.17A from 1.58A. The results suggest that the proposed deadbeat control strategy with plug-in repetitive controller restrains harmonics and solves the unbalanced problem of three-phase system effectively, which can prove the effectiveness of the control strategy.