Rojin R.K, Ajay Amrit Raj
Power quality issues are of great concern in transmission and distribution system nowadays due to the sensitive nature of the loads. The sensitive nature of the load increases with the advent of power electronic technology. In distribution systems, current harmonics, voltage sag/swell are more prominent. Power quality problems cannot be eliminated by using conventional filters. Therefore power electronic based active power filters (APF) are most commonly used nowadays. Unified Power Quality Conditioner (UPQC) is a custom power device, used to enhance power quality in distribution system. UPQC is an integration of shunt and series active power filter. In this paper fuzzy logic controller (FLC) based UPQC for a 3 phase 4 wire distribution system is proposed. The proposed system has the capability to mitigate power quality problems in a cost effective manner with reduced dc link voltage rating. The proposed system eliminates the limitations of PI controller. In this paper hysteresis controller is used to control the voltage source inverter (VSI) switches of UPQC. The performance of the proposed system is verified using MATLAB/Simulink.