Power Quality Improvement of Grid Interconnected 3-Phase 4-Wire Distribution System

This paper presents a grid interfacing inverter that compensates power quality problems and it can also interface renewable energy sources with the electric grid. The grid interfacing inverter can effectively be utilized to perform following functions: 1) transfer of active power harvested from the renewable resources; 2) load reactive power demand support; 3) current harmonic compensation at PCC; and 4) current unbalance and neutral current compensation in case of 3-phase 4-wire system. The ability of fuzzy logic to handle rough and unpredictable real world data made it suitable for a wide variety of applications, especially, when the models or processes are too complex to be analyzed by classical methods. In this paper fuzzy logic controller is used for controlling the DC capacitor voltage. Simulations using MATLAB / SIMULINK are carried out to verify the performance of the proposed controller. The results show that the proposed controller has fast dynamic response, high accuracy of tracking the DC-voltage reference, and strong robustness to load parameters variation.