Virtual flux based direct power control of shunt active filter

Active filters are effective solutions to eliminating harmonic pollution and improving reactive power in the presence of nonlinear loads and unbalanced sources. To reduce the disturbances caused by this type of load, we propose, in this paper, a new control strategy of a shunt active filter. Our method aims to improve electrical quantity behavior in steady and dynamic states, while reducing the installing cost of the filter, through eliminating AC line voltage sensors. This is established by Direct Power Control (DPC), based on Virtual Flux (VF) estimation of the electrical network, using a switching function table. Facing disturbances affecting the electrical network, we have integrated a Phase Locked Loop (PLL), and have implemented and tested our new control strategy in a Matlab/Simulink environment. The results obtained show the effectiveness of the active filter control algorithm in eliminating harmonic currents, and shows an improvement in the reactive power injected from nonlinear loads, which has allowed us to confirm the robustness of the proposed strategy. (C) 2014 Sharif University of Technology. All rights reserved.