Abstarct: The role of an automatic voltage regulator (AVR) in excitation system is to hold and control the terminal voltage magnitude of a synchronous generator at a specified level. Unstablity in AVR cause seriously affect in stability of the power system. In this dissertation, using the concept of fractional calculus, the design and calculation of optimal coefficients of an optimum Fractional Order Proportioanl-Integral-Derivative controller (FOPID) using artificial intelligence techniques and imperial competition algorithm (ICA) algorithm for design an optimum Fractional Order Proportioanl-Integral-Derivative controller (FOPID) parametrs, That tuned to improve the performance of an automatic voltage regulator (AVR) in power generation systems. The components of the excitation system simulated and by defining a suitable cost function, optimization has been compared in evolutionary algorithms. Simulation and results obtained from the dissertation indicate the optimal performance of the controller designed against the uncertainties exists in system parameters.