Self tuning Fuzzy PI controller for active filter optimized by Ant colony method

Recently active filters and fuzzy logic are being used in power systems. In this paper, an active filter to eliminate harmonics of line current and correct its waveform has been used. The controller of this active filter is using fuzzy logic as its base. First this filter defines the injection compensation current by Fourier analysis and then the controller switches the filter to produce and inject this current to the system. In order to have better operation, this controller is optimized by Ant Colony System (ANS). For improving filter performance for light loads, the controller is modified by adding another tuning controller which tunes the output parameter of the main controller. Simulation shows that installation of this controller in the system eliminates harmonics and corrects the waveform of the line current.