电容中点式有源电力滤波器数学模型及电流复合控制策略

Analytical Model and Current Composite Control Strategy for Mid-Point Capacitor Three-Phase Four-Wire Shunt Active Power Filter

三相四线并联型有源电力滤波器通常可用来补偿非线性负载所引起的谐波和无功电流,以及负载不平衡引起的负序或零序电流。本文描述了电容中点型三相四线有源电力滤波器在abc及dq0坐标系下的数学模型,并由此给出了dq0同步旋转坐标系下的一种系统控制策略。由于有源电力滤波器指令为快速变化的交流谐波信号,传统的PI控制由于带宽有限,稳态精度较差。因此,提出了基于PI控制和重复控制并联的电流复合控制策略,利用重复控制对于周期扰动信号无差跟踪的特点来提高稳态精度,同时,PI控制又能保证良好的动态性能。仿真和实验结果验证该控制策略的可行性和有效性。

Three-phase four-wire shunt active power filters （APF） are often employed to compensate the harmonics and reactive current derived from non-linear load, as well as the negative-sequence and zero-sequence currents due to the unbalance of the load. This paper describes the analytical model for the mid-point capacitor three-phase four wire shunt active power filter. Since the reterence of the APF is AC harmonic signals ,the performance under PI control is not satisfierd due to its limited bandwidth. Therefore, the paper gives a composite current control strategy, where the PI controller are parallel with repetitive controller to compensation harmonics together. The advanced repetitive controller is used to eliminate the steady current tracking error caused by cyclic disturbance signal to improve the compensation precision , while the PI controller can ensure satisfied dynamic response performance. The feasibility and efficiency of the composite control architecture is verified completely by simulation and experimental results.