Smoothing control of generated power fluctuation of WTG using gain-scheduled control

To reduce the impact of large output power fluctuations of a wind power generator introduced in a power system usually, a battery is installed. However, if a large battery is used, the capital cost of wind turbine system will increase. Hence the smaller size of battery is preferable to reduce capital cost. This paper presents a methodology for controlling the combined output and the battery storage energy. The system consists of a wind turbine generator (WTG) and a battery energy storage system (BESS). The generated power fluctuations in low and high frequency components are smoothed by a pitch angle control of the WTG and battery charge/discharge. The proposed control reduces the rated kWh capacity of battery and the mechanical stress of windmill blade. In the proposed method, the gain-scheduled control theory is applied to achieve good response and robustness for high nonlinearity of the WTG model. The effectiveness of the proposed control system is validated by simulation results.