Novel current control scheme with deadbeat algorithm and adaptive line enhancer for three-phase current-source active power filter

For an active power filter (APF), a three-phase current source PWM converter using IGBTs is not always used in place of a three-phase voltage source PWM converter with a voltage regulated DC capacitor. This is due to the difficulty of current control implementation for three-phase current source PWM converter. In this paper, the effective method to apply three-phase current-source PWM converter with a deadbeat controller to APF is presented. In this APF, the compensation of current harmonics is attained by setting the control purpose compensating the instantaneous reactive current component in load current and reducing the ripple in the instantaneous actual current component. In three-phase current source PWM converter, the time-optimal response for utility AC grid side input current is two-dimensional finite time settling response, in which two sampling periods are required for a settling time. To cancel this delay and one more delay caused by DSP control strategy, the reference value of three sampling periods ahead has to be predicted. For this prediction, the adaptive filter is introduced. Finally, it is proven from an experimental point of view that the compensating ability of this APF is very accurate though the PWM frequency is rather low.