The Active Power Filter (APF) is a dynamic harmonic mitigation device based on power electronics technology.It first detects the load current in real time through a current sensor and separates the harmonic current components via an algorithm. 

Then, the IGBT inverter unit generates a compensation current with “equal amplitude and opposite phase,” which cancels out the original harmonic current. This achieves the purpose of harmonic filtering, thereby improving power quality and ensuring the stable operation of the power system and electrical equipment.