Fruzzy logic controller for three-phase four-leg five-level shunt active po\iler filter under unbalanced non-rinear load and distorted voltage conditions

Abstract

This paper presents a five-level inverter which is used as a three-phase four leg shunt active power f,lter, taking advantages of the multilevel inverter such as low harmonic distortion and reduced switching losses. It is used to suppress harmonic current, compensate reactive power and neutral line current and balance the load currents under unbalanced nonlinear load and distorted voltage conditions. The active power filter control is essentially based on the use of self tuning filters for the reference current generation arrd afuzzy logic curent conûoller. This study is divided in two parts. The flrst one deals with the harmonic isolator which generates the harmonic reference currents. The second part focuses on the generation of the switching pattern of the inverter by using a fizzy logic controller applied and extended to a four leg five level shunt active power fllter. The MATLAB Fuzzy Logic Toolbox is used for implementing the fltzzy logic control algorithm. The performance of the proposed shunt active power fllter controller is found considerably effective and adequate to compensate harmonics, reactive power and neutral current and balance load currents under distorted voltage conditions.