The determination on DC capacitor parameter in Active Power Filter

On the basis of the instantaneous reactive power theory the energy flow relationships of ac and dc sides in APF inverters for different compensation purposes are analyzed. The voltage fluctuation is caused by the inverter power losses and instantaneous active power ac component. Based on the principle and mathematical model of Active Power Filter (APF), this paper proposes an improved method which aims to solve the determination for dc capacitor parameter. Taking a three phase non-controllable load as an example, the calculation method for capacitor parameter selection is given. The voltage fluctuation of dc capacitor is less than 0.55 percent. Then it turns out to be true by the outcome of the emulation.