APF有源电力滤波柜通过外部电流互感器CT，实时检验负载电流，并通过内部DSP计算，提取出负载电流的谐波成分，然后通过PWM信号发送给内部IGBT,控制逆变器产生一个和负载谐波大小相等、方向相反的电流注入到电网中补偿谐波电流，实现滤波功能。

The active power filter detects the load current in real time through the external current transformer CT, and extractsharmonic components of the load current through internal DSP calculation, and then sends the harmonic components to the internal IGBT through PWM signals to control the inverter to generate a current with the same magnitude and oppositedirection as the load harmonic and inject the current into the power grid to compensate the harmonic current, thus realizing the filtering function.

有源滤波柜是一种可以动态抑制谐波和补偿无功功率的新型电力电子设备。可以补偿不同幅度和频率以及不同无功功率的谐波。有源滤波器柜因设备需要供电（补偿主回路谐波）而称为有源滤波器。它的应用可以克服传统的谐波抑制和无功功率补偿的方法，如LC滤波器（传统补偿只能固定），实现动态跟踪补偿，并在同一时间进行补偿的谐波和无功功率。