Application of fuzzy systems in the control of a shunt active power filter with four-leg topology

摘要

This paper presents the application of fuzzyudcontrollers to act in the current control loop of a shunt activeudpower filter (SAPF). The SAPF consists of a three-phaseudinverter with four-leg topology, and it has been used to reduceudthe harmonic content produced by nonlinear loads, as well as, inudthe reactive power compensation. The generation of theudreference currents is based on the synchronous reference frameud(SRF), which requires the use of a PLL (Phase Locked Loop)udsynchronization algorithm with the grid. The classic PI controludis here replaced by a fuzzy controller that has features thatudallows fast convergence and robustness when there areudparametric variations in the physical system. Results obtainedudfrom simulations are presented to validate the approach and touddemonstrate the performance of the filter in the suppression ofudharmonic currents and reactive power.