POWER QUALITY IMPROVEMENT BY UPQC WITH FUZZY LOGIC CONTROLLER.

Abstract

This paper presents analysis of a three-phase four wire Unified Power Quality Conditioner (UPQC) with fully fuzzy logic controller. The UPQC is a custom power device which is integrated by series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt and series APF is carried out by using a three-phase, three legs Voltage Source Inverter (VSI). In series, shunt active filter, the fundamental voltages, currents are extracted by modified synchronous reference frame technique; Switching pulses for both filters generated by fuzzy logic current controller (FCC).The capacitance voltage is balanced by fuzzy logic controller .performance of the fuzzy logic based control algorithm of shunt active filter with series active filter is evaluated in terms of eliminating the power quality problems in a three-phase, three-wire distribution system with non-linear and unbalanced load conditions. Fuzzy logic control is used for dc capacitance balancing. The control algorithm is made by use of MATLAB / Simulink-based simulations environment and the results are verified by proto type hardware set up