Optimization Of Wind Turbine Pitch Angle Control Considering The Influence Of Wind Speed And Dispatched Power

With the high integration of wind power to power grid,in order to improve the stability and quality of grid frequency,it is urgent to develop wind power to participate in the automatic generation control(AGC)of power system.In the traditional maximizing efficiency mode,the power control of the wind turbine aims to maximize the power generation efficiency.The maximum power point tracking is realized by adjusting the electromagnetic power,and pitch regulation is only utilized when rotor speed/ output power of wind turbine reaches the rated value.However,in the AGC mode,the electromagnetic power of the wind turbine needs to track the power command of power grid and can no longer participate in rotor speed regulation of the wind turbine.Accordingly,pitch control will mainly undertake the task of maintaining the dynamic stability of the wind turbine.Therefore,the switching of wind turbine operating mode poses greater challenges to the design of pitch angle control.This paper studies the pitch control in AGC mode.It is found that besides wind speed,the power command of power grid also affects the adjustment performance of rotor speed.Furthermore,based on the proportional-integral pitch controller,the influence mechanism of two operating conditions(ie,wind speed and power command)is analyzed in this paper.It is found that both two operating conditions will influence the sensitivity of pitch angle to aerodynamic power,which means the rate of pitch angle regulation need to be adjusted according to the sensitivity in order to obtain a stable rotor speed regulation performance.Therefore,based on the analysis of the effect of operating conditions on the sensitivity,a pitch control strategy based on linear active disturbances rejection control(LADRC)is proposed.Since LADRC can handle model uncertainty and external interference,the LADRC pitch controller can be applied to complex and variable operating conditions,so the speed regulation performance of the wind turbine can be effectively improved.Finally,simulation and experiment results show that,compared with the existing pitch control,the proposed method has smaller overshoot and shorter adjustment time.Meanwhile,the new method has a good suppression effect on the speed noise generated in the experiment.