Robust Frequency Control of Island Microgrid using PI Controller Tuned by ICA-based Fuzzy Logic

Renewable energies are used by micro grid (MG) to produce electrical power. Scatered loads receive service from MG in both Island and Grid connected operation modes. Uncertainties of power system and natural deviations of power produced by renewable energies attenuate the performance of classic controllers. In this paper, fuzzy system determines the parameters of PI controller in response to this challenge. The Imperialist competitive algorithm (ICA) optimizes the nominal values of controller parameters and the membership functions of the proposed fuzzy system. The interval of the proposed controller parameters are determined by Kharitonov's theorem to ensure the stability of the closed loop system. Comparison of RMS, overshoot and undershoot, number of oscillations, and settling time of the frequency deviations of the proposed control scheme with two other controllers in several load changes demonstrates the better performance of the proposed controller. Considering the uncertainties of system parameters proves that the proposed controller is robust.