Coordinate control of wind turbine and battery in wind power generator system

Due to the large output power fluctuations of a wind power generator, a battery is installed to smooth these fluctuations. However, if a large battery is installed in the power system, the capital cost for wind power system will increase. Hence the smallest size of battery is preferable to save on capital cost. In this paper, we propose a methodology for controlling combined system output and optimal capacity of battery system. The system consists of a wind power generator and battery energy storage system. The generated power fluctuation in low and high frequency domain are smoothed by pitch angle control and battery charge or discharge. This coordinated control reduces the rated battery capacity and windmill blade stress. In our proposed method, we apply H_infin control theory to achieve good response and robustness. The effectiveness of the proposed control system is validated by simulations.