Active Filter (APF)

Basing on application of power electronic technique, APF is the best soltion for filtering harmonics.

APF is suitable for multi application accasions. We can design the most suitable installation solution for industrial occasions, distribution rooms, machine rooms etc. Because of flexible installation and convenient operation, our active power filters bring huge conveniences for solution design, on-site installation and after- sale maintaining.

Harmonic harms are including as followings.

  • Increase line loss, causing cables overheated, insulation aging and reducing efficiency of power supply.
  • Make capacitors overload, overheated, breakdown and accelerated aging.
  • Cause electric equipments malfunction and no response and power outage.
  • Induce electric network syntony and cause harmonic over-voltage and over-current.
  • Affect effeciency and normal operation of electric motors, producing vibration and noise and reducing service life.
  • Damage sensitive devices in electric network and cause production equipments operate unsteadily.
  • Interference communication and electronic equipments, causing control system failure.
  • Zero-sequence harmonic will cause neutral current too high.Neutral lines will heating and burn up.


When APF connects to electric network in parallel, it will measure harmonics and generate reverse compensation current to filtering harmonics by inverting.

APF measures the real-time current signals by external CT, analyzing and getting data of harmonic content. According to measured data, APF will control IGBT to generate compensating current which has the same value and the reverse phase of electric network system’s harmonics, realizing the function of filtering harmonics.

Because APF’s compensating current outputs activly with the changing of system harmonic content, it will not be over compensated. Meanwhile, APF has a function of limiting input capacity which will protect APF to avoid over-load outputing effectively.

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