Active Power Smoothing Control Of Wind Generation System

Wind power is a clean and renewable energy. The fluctuations of wind power often occur as the stochastic feature of wind speed. With the increase of the wind power capacity in power grid, the change of power and frequency in power system will exceed the limit range when the fluctuation of the wind speed is large. The power quality of wind power and stability of system are influenced. So, it is important to control the output power level of the wind generation system. The wind speed prediction and the dynamic compensation are used to Variable Pitch and Variable Speed system with Doubly Fed Induction Generator to research the output power level.Firstly, the wind generation system is simplified to one order dynamic system using inverse-system method. And the inverse-system of the wind generation system is designed to cascade with the original system. One-step ahead prediction of wind speed is achieved by both Kalman filter predict model and auto regressive integrated moving average (ARIMA) model. The predicted wind speed is regarded as the input of the cascade connection system. It makes sense for regulating the pitch angle advance and avoiding regulating the pitch angle frequently. Secondly, the inverse-system is designed to cascade with the wind generator model transferred to a"pseudo-linear"system. In order to compensate the altitudinal nonlinearity of the wind turbine model, dynamic compensation controller based on the error normalization method is designed to compensate the pitch angle and the mechanical torque respectively. Thus the fluctuations of the mechanical torque and the output power are reduced by regulating the pitch angle quickly. Finally, based on the theoretical analysis, the simulation experiments are achieved by MATLAB/SIMULINK, and the corresponding data and figures are compared. The simulation results show that the above schemes are feasible.