Fuzzy controlled parallel active power filter

Abstract

Active filters are widely employed in distribution system to reduce the harmonics produced by non-linear loads. These results in voltage distortion and leads to various power quality problems. Shunt Active Power Filters are the best solution for the elimination of harmonics occurred in the power system. This paper presents the optimization of shunt active power filter parameters based on fuzzy logic control, which is employed to drive the switching signals and also to choose the optimal value of the coupling inductance. The fuzzy control is based on a linguistic description and does not require a mathematical model of the system. It can adapt its gain according to the changes in load. The indirect current control method is used for calculating the compensating currents. A fuzzy logic based controller is developed to control the voltage of the DC side Capacitor. The conventional hysteresis controller gives very fast response and good accuracy, but it causes uneven switching. This work presents and compares the performance of the fuzzy-controller with a conventional controller under constant load. The harmonic distortions are analysed and compared. The total Harmonic Distortion, Individual harmonic content with respect to % of fundamental in Supply current, have been analysed. The proposed systems are implemented with Mat lab/Simulink.