Active power filters can be widely used in industrial, commercial and institutional distribution networks, such as power systems, electrolytic electroplating enterprises, water treatment equipment, petrochemical enterprises, large shopping malls and office buildings, precision electronics enterprises, airport/port power supply systems, medical institutions and so on. According to different application objects, the application of active power filter will play a role in ensuring power supply reliability, reducing interference, improving product quality, prolonging equipment life and reducing equipment damage.