为提高有源电力滤波器(active power filter,APF)的补偿性能和动态响应,提出采用选择性谐波补偿控制策略对待补偿谐波分量进行跟踪。针对普速和高速电力机车负荷特性,采用基于同步基波旋转坐标系的谐波电流检测方法及矢量比例积分(vector proportional-integral,VPI)调节器的选择谐波补偿方式,以减少电流控制环节的运算量,在补偿装置容量有限时可以选择补偿危害最大的谐波成分并提高待补偿谐波分量的跟踪精度。最后通过MATLAB仿真研究,电流总畸变率(total harmonic distortion,THD)由33.9%降至2.99%,负序与无功问题均得到解决,验证了VPI控制方法可以有效提高补偿精度,指令电流为混合谐波指令时,可以对其中主要次数谐波进行有效选择及跟踪,跟踪误差小,动态响应快,能够解决电气化铁路中的电能质量问题。
To improve the compensation characteristic and dynamic response of active power filter (APF), we put forward a selective harmonic current control strategy for APF to track those components to be compensated. According to the characteristics of normal and high speed locomotives, we adopted a detection method of harmonic currents based on synchronous rotating reference coordinates and VPI control scheme for selective harmonics compensation so as to reduce calculation of current control.Therefore, in the case of harmonic currents larger than the APF capability, the control system could selectively compensate only the most harmful harmonics. MATLAB simulation studies show that the total harmonic distortion of current will decrease from 33.9% to 2.99%, the problems of reactive power and negative sequence can be solved, thus it is verified the VPI control scheme can improve the compensation accuracy and select the main harmonics from the mixed reference, the advantages of smaller tracking error and faster dynamic response can improve electric energy quality.