Flexible compensate arithmetic of the three-phase four-wire Active Power Filter

For adapting to the need of the harmonic compensate in the complicated industrial environment, this paper shows a 3-phase 4-wire shunt active power filter (APF) with the flexible harmonic compensate arithmetic. First the paper introduced the arithmetic about how to pick-up the harmonic current which is fundamental-wave-pick-up arithmetic and direct harmonic-wave-pick-up arithmetic, then discussed their advantage and fault. Finally, we introduced a new arithmetic which can adapt the most complicated industrial environment and improve the stability and performance of the APF. It can compensate flexibly the harmonic component, passive power component or imbalance component. The simulation and experiment result validated the arithmetic.