基于LCL滤波器的高稳态性能并联有源电力滤波器

Shunt Active Power Filter With High Steady-State Performance Based on LCL-Filter

并联有源电力滤波器(APF)适用于补偿电流源型谐波,通常由于谐波电流较大的变化率以及电流环的稳态误差,进行高精度补偿具有一定难度。本文采用LCL滤波器兼顾补偿电流带宽和开关纹波的滤除效果,从补偿电流变化率和滤波电容高频分流的角度详细讨论了滤波器的设计方法。同时,将重复控制直接应用于LCL滤波器的补偿电流控制,带有惯性的微分补偿器保证了控制环的稳定性和稳态精度。采用上述措施后,补偿后的电网电流在高、低频段都有较低的谐波含量。实验结果证明了本文方案的有效性。

Shunt active power filter（APF） is suitable to compensate current-type harmonics generated by nonlinear load,but high compensation precision is difficult to be obtained due to very high slew rate of harmonic current e.g.inductive rectifier and phase lag of close-loop control system.In this paper,LCL-filter is used as output filter to obtain high slew rate of compensation current and sufficient attenuation ratio for switching frequency.The design approach of LCL-filter based on slew rate of compensation current and bypass effect for switching ripple is proposed.What＇s more,repetitive control with differential compensator is adopted to eliminate steady-state error of control loop.Based on these two approaches,very high steady-state compensation performance both at low and high frequency range can be obtained.Experimental results validate the feasibility of the schemes proposed by this paper.