四桥臂APF电流跟踪控制方法研究

为解决三相四线制不对称电网系统的谐波污染问题，通过对三相四桥臂电路拓扑结构进行分析。针对传统的三维空间矢量调制方法，首先阐明了其不能用于四桥臂APF电流跟踪的原因。在此基础上，结合三桥臂APF的电流跟踪控制方法，在二维空间矢量控制策略上增加三维坐标垂直坐标轴上的电流跟踪策略，将三维空间矢量划分为12个三棱柱，而非传统的24个四面体，并根据垂直坐标轴分量的正负情况给出了电压，电流矢量的判定方法，得到了三维矢量电流跟踪控制下的输出矢量的选取判定表，实现了四桥臂APF对谐波电流的有效补偿。仿真和实验结果证明了该方法的正确性与有效性。

Research on current tracking control method for four-leg APF

In this paper, a control algorithm used in four-leg active power filter （APF） is presented to resolve the problem of harmonic pollution in unbalanced power system. In order to compensate the harmonic current in four-leg APF, based on the analysis of circuit of four-leg APF, this paper describes the shortcoming of conventional three dimensional vector control used in four-leg APF current track. Based on three-leg APF current track method, com-bining the current tracking control algorithm of three-leg APF with three dimensional coordinate vertical axis current control, which makes the three dimensional space vector distribution into 12 triangular prisms, instead of conven-tional 24 tetrahedrons, also the appropriate detection of voltage and current vector is proposed. At last, output vec-tor which select judgment tables of three dimension vector current tracking control is available. The improved cur-rent tracking control algorithm of three-dimensional space vector realizes the effective compensation of harmonic cur-rent. The simulation and experiment results show the correctness and the availability of this method.