An improved control strategy for three-phase four-wire active power filter based on vector-resonant control

This paper proposes an advanced non-harmonic detection control strategy for three-phase four-wire Active Power Filter (APF) based on improved Vector-Resonant Control (VRC). The mathematical model of the split-capacitor configuration is established with the source currents and the DC bus voltage as state variables. The proposed control scheme detects and regulates the source currents directly, without harmonic detectors, which could ensure the accuracy of the compensation and could improve the dynamic response of the system. A current loop controller is improved, which has superiority of frequency adaptation and stability margin. Finally, all conclusions in this paper are validated by Matlab/Simulink, and a 50-kW APF prototype with the proposed control strategy is implemented successfully.