Analysis of Power Quality Enhancement in MFGCI with PI and Fuzzy based Active Power Control

Abstract

Recent scenario in the distribution system is harmonics created by Non-linear load and unbalance current. It affects not only the working of adjacent loads but also shorten the life of power equipment by creating excessive losses. In this paper, a fuzzy controlled shunt active power filter is described to maintain the (Total Harmonic Distortion) THD within the allowable limits defined by IEEE Std. 519-1992 and to reduce reactive power and improve power factor. This Filter draws the opposite harmonics containing current from the load so that source current remain sinusoidal and undistorted. Fuzzy logic controller is used to control the shunt active power filter and the performance of the shunt active filter control strategies has been evaluated in terms of harmonic mitigation. Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. A fully functional MATLAB based Simulink model of Shunt Active Power Filter for different types of load (nonlinear, unbalance, both) has been designed based on `Instantaneous Power Theory' or `p-q Theory'. The results of simulation comply with all the features described by the theory, justifying employment of Shunt Active Power Filter (SAPF) with fuzzy controller improves power quality compared to conventional Proportional Integral(PI) controller.