A Novel DSP Based Current Controller with Fuzzy Variable-Band hysteresis for Active Power Filters

Conventional hysteresis current controller with fixed-band for active power filter (APF) has a high maximum switching frequency (MSF). To limit the MSF within the limit of inverter switches, a novel fuzzy hysteresis band current controller for active power filter is proposed in this paper. The band height, based on fuzzy control principle, is changed with the value of the error current and the rate of change of the error current, consequently the switching frequency is controllable. The fuzzy hysteresis band current control and harmonics compensation algorithm are both based on digital signal processor (DSP), which reduce the analogue circuitry and enhances the system´s immunity to noise. The simulation results by MATLAB show that control strategy proposed is feasible