A fuzzy hysteresis voltage and current control of an Unified Power Quality Conditioner

This paper presents a new control design of an Unified Power Quality Conditioner (UPQC) for harmonics and voltage compensation in a power distribution system. The topology of the UPQC is based on a combination of two 3-phase series and parallel active power filters. The determination of voltage references for series active power filter is based on a robust three-phase digital phase locked loop (PLL) system using fuzzy regulator. Control strategies related to fuzzy hysteresis band voltage and current control methods, where the band is modulated with the system parameters to maintain the modulation frequency nearly constant are developed. Simulation results based on MATLAB/SIMULINK are presented to verify the effectiveness and the viability of the proposed control technique.