SYNCHRONOUS REFERENCE FRAME THEORY BASED CONTROLLER FOR UNIFIED POWER QUALITY CONDITIONER IN THREE-PHASE FOUR-WIRE DISTRIBUTION SYSTEM

Abstract

This paper presents a Synchronous Reference Frame (SRF) theory based control strategy for a Three-Phase Four-Wire Unified Power Quality Conditioner (3P4W UPQC) in distribution system to compensate the Power Quality (PQ) problems under unbalanced, distorted supply voltage and /or load conditions. The 3P4W UPQC is realized by a combination of series and shunt Active Power Filters (APF) sharing with common DC link capacitor. The series APF is realized using a three-phase three-leg Voltage Source Inverter (VSI) , while shunt APF is realized using a three-phase four-leg VSI. A dynamic model of the 3P4W UPQC system is developed in the MATLAB / SIMULINK sim power system software. The simulation results validates the effectiveness and capabilities of SRF based control strategy of UPQC to mitigate various power quality problems, both steady and transient state operations in the 3P4W distribution system