Nonlinear Sliding Mode Control Design for Shunt Active Power Filter with the Minimization of Load Current

This paper proposes a new method of sliding mode base controller for shunt active power filter to compensate the harmonic currents of a load. In this controller there isn't any need to PI DC voltage controller to regulate the DC capacitor voltage of shunt active power filter. In this method, first the reference currents of shunt active power filter that should be tracked to reduce or eliminate the harmonic currents of line and power loss are derived based on Lagrange function. In the Lagrange function, the active components of load currents are minimized with the constraint of three-phase reactive power to zero. Then, three sliding surfaces are defined such that three-phase currents and voltage of capacitors in shunt active power filter are gone to reference values. The coefficients of sliding surfaces are derived such that the sliding surfaces go to zero with fast dynamic and more error reduction than conventional sliding mode controller.