对电流谐波的准确快速检测是决定有源电力滤波器补偿性能的一个重要环节．文中结合无功功率理论和佛布迪(FBD)法，提出一种改进的三相四线制系统谐波电流检测方法． 该方法省去了不必要的零序电流分离环节，降低了算法的复杂性，减少了传统瞬时无功功率法因坐标变换引起的矩阵运算，提高了谐波检测的实时性和动态性能． 对零轴电流进行单独提取，进行上下电容均压控制，确保在三相四线制电容中分式有源电力滤波器中的适用性． 采用改进的移动平均值算法代替低通滤波器，避免低通滤波器采样和计算过程中产生的滞后误差，提高了谐波的检测精度． 通过在三相四线制电容中分式有源电力滤波器中的仿真和实验，验证了所提出的方法的可行性与优越性．

Accurate and fast harmonic current detection plays an important role in determining the compensationperformance of active power filters.In this paper,an improved three-phase four-wire harmonic current detectionmethod is proposed by combining the traditional instantaneous reactive power theory with the FBD method.In thismethod,the algorithm complexity is reduced by cutting the unnecessary separation link of the zero-sequence cur-rent,and the matrix operations caused by the coordinate transformation in the traditional instantaneous reactivepower method are also reduced,thus improving the real-time and dynamic performance of the harmonic current de-tection.Moreover,the zero-axiscurrent is compensated separately and the balance control of upper and lower capac-itor voltages is conducted,so as to ensure the applicability of the active power filter of three-phase four-wire capaci-tors.In order to reduce the hysteresis error caused by the low-pass filter during the sampling and calculation and toimprove the harmonic detection accuracy,an improved moving average algorithm is adopted to replace the low-passfilter.Finally,the feasibility and superiority of the proposed method are verified through the simulation and experi-ment in a three-phase four-wire active power filter.