Elham Ganji - Department of Electrical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Reyhaneh Kardehi Moghaddam - Department of Electrical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Mahdi Zarif - Department of Electrical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran

This paper presents a new study on isolated WT/FC/UC hybrid power generation system to control the frequency deviation of grid as well as maximum power extraction of WT system. The WT system is the main power source of the proposed hybrid system, while the long-term energy balance is supposed to be generated by FC, besides, as for the short-term compensation we have used the UC. In order to track maximum power point in the wind turbine system, at all operating condition, an efficient robust sliding mode control strategy is proposed. This proposed MPPT controller guarantees stability and high robustness to deal with model uncertainties of the turbine and generator. In this part, to demonstrate the effectiveness and reliability of the SMC controller, comparison with nonlinear Indirect Speed Control (ISC) control was performed. Then, by applying the optimal droop controller, a proper balance between the production and consumption of the grid is maintained via determining the precise reference values for UC and FC. To do so, the Improved Particle Swarm Optimization (IPSO) algorithm is used to optimize the droop gains and the frequency deviation in the various states changing of generated power and consumed power declines significantly compared to conventional droop controller and improved droop controller. Real weather data and practical load demand profile has verified the performance of proposed strategies in various conditions. Using MATLAB/SIMULINK by detailed mathematical and electrical models of proposed isolated hybrid system, simulation results are presented to prove the efficiency of the introduced model and strategies.

Frequency control, Maximum Power Point Tracker, dynamic modeling, Isolated Network, Sliding Mode Control, Improved particle swarm optimization (IPSO), optimal droop control