The Study on DC Capacitor Parameter Determination in Active Power Filter

Based on the principle and the mathematical model of Active Power Filter(APF), this paper proposes a improved method which is aiming to solve the selection for dc capacitor parameter. 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. Taking a three-phase non-controllable load as an example, the calculation method of capacitor parameter selection is given. The voltage fluctuation of dc capacitor is less than 0.55 per cent. Then it is turned out to be true by the outcome of emulation