指定次谐波补偿并联型有源滤波器电流重构限流策略

Current-limiting Strategy for Current Reconstruction of Shunt Active Power Filter with Specified Sub-harmonic Compensation

针对有源滤波器指定次谐波补偿时负载谐波电流突增导致有源滤波器过流的现象,在并联型有源滤波器传统比例限流的基础上,提出了一种谐波电流重构的限流策略。本策略首先利用滑窗迭代FFT的方法,求出指定次谐波电流的幅值与相位,然后通过指定次谐波电流的叠加重构出被补偿的谐波电流,重构电流与比例系数之积作为新的参考电流参与并联型有源滤波器的控制。此方法可充分利用并联型有源滤波器的补偿能力,实现并联型有源滤波器的准确限流,并能使并联型有源滤波器在超出其补偿容量的系统中安全运行。仿真和试验结果验证了本方法的正确性与有效性。

When the specified sub-harmonic compensation of active power filter(APF)is performed,the load harm-onic current jump will result in over-current of APF.In this paper,a current-limiting strategy for the reconstruction of harmonic current is proposed based on the traditional proportional current-limiting of shunt active power filter(SAPF).First,the amplitude and phase of the specified sub-harmonic current are obtained using the sliding window iterative FFT analysis under this strategy.Then,the compensated harmonic current is reconstructed by the superposition of the specified sub-harmonic current,and the product of the reconstructed current and the proportional coefficient is used as a new reference current for the control of SAPF.This method can make full use of the compensation capability of SAPF,thus realizing the accurate current-limiting of SAPF and ensuring its safe operation beyond the compensation capacity of the system.Simulation and experimental results verified the validity and effectiveness of the propose method.