APF is composed of command current computing circuit and compensation current generating circuit. Command current computing circuit conducts real-time monitoring of current in circuit; switch the analogue current signals into digital signals, and send the signals into DSP for handling; separate harmonics and fundamental wave, send drive pulse in form of PWM signals to compensation current generating circuit; drive IGBT power module, produce compensation current input network which has the same amplitude as harmonic amplitude and inverse polarity; compensate or balance out harmonic current, eliminate power harmonics actively, and thus realize the dynamic quick and complement treatment of power harmonics.
Dynamic reactive power compensation: While filtering harmonics, according to detected need for reactive power compensation, APF command current computing circuit can control internal capative and inductive fundamental current of compensation current generating circuit, conduct real-time compensation, set the target value of reactive power compensation through operation board. There are 4 working modes for choice, namely, “filter priority”, “reactive power priority”, “harmonic filter only”, “and reactive power compensation only”. The working mode should be selected according to specific conditions of power distribution system.
Correct unbalanced 3 phases: APF can compensate the unbalanced 3 phases respectively. It can conduct phase adjustment of active power through DC Energy Storage Systems shared by 3 phases, thus to correct unbalanced load of 3 phases. The operation of this function can also be set by operation board.
Computers and Peripherals
Variable Frequency Drives (VFDs)
Uninterruptible Power Supplies
DC Power Systems/Chargers