Active Filter Control Method Based on Direct Power Control for Compensating Reactive Powers due to Unbalanced Voltages and Nonlinear Loads

Active filters have proven to be more effective than passive techniques to improve power quality and to solve harmonic and power factor problems due to nonlinear loads. This paper proposes a control scheme based on the instantaneous active and reactive power. The inverter of this active filter is a three-phase, two-level converter. Space vector technique is used as modulators and pattern generators for the Pulse Width Modulated converter. Virtual Flux and a Phase Locked Loop based on a Double Synchronous Reference Frame cause this control system be resistant to the majority of line voltage disturbances. Good dynamic response, independent control of active and reactive powers and also unity power factor of converter are advantages of the proposed method. The operation of the proposed control strategy is verified in MATLAB simulation environment.