Pitch Angle Control Of Large Wind Turbine Based On Active Disturbance Rejection

Due to the challenges faced by the current world environment,the demand for energy is increasing day by day,and the wind in renewable energy develops rapidly with its advantages of low cost and reliability.In this paper,active disturbance rejection control(ADRC)technique is proposed to design the pitch angle model of large wind turbine(WTG)is an advanced control method proposed by Professor Han Jingqing.Its core idea is to treat the internal and external disturbances of the system as a "total disturbance" and estimate and compensate it by designing an extended state observer.In order to facilitate the parameter tuning of the ADRC controller and apply it to industrial scenes,Professor Gao Zhiqiang improved and proposed a linear active disturbance rejection controller(LADRC).The main contents of the paper are as follows:1.The wind turbine pitch angle model with time delay in the hydraulic drive unit of variable pitch control system is analyzed Under different model configurations and working conditions,three sets of wind turbine pitch angle models with different rated power are obtained,respectively.For this kind of high-order oscillation model with time delay,its dynamic characteristics are studied with Bode diagram,closed-loop zero-pole diagram of the system and time-domain step responses.The difficulty of controller design caused by the existence of time delay and non-minimum phase zero of the controlled plant is analyzed.2.Considering that the controlled system is oscillatory,a robust controller is designed with stability and reliability as the primary goal.The H∞ controller is designed by loop shaping method.Compared with the existing PI controller,the simulation results show that although the tracking ability of the H∞ controller is improved,the disturbance response is still oscillatory,and the order of the controller is too high to realized,thus ADRC with strong disturbance rejection ability will be considered to improve the control performance.3.A first-order linear active disturbance rejection controller is optimized by minimizinge a cost function with extremum-seeking algorithm under certain robustness constraints.In the Matlab/Simulink environment,the simulation test is carried out by changing the working conditions.The results show that the LADRC’s optimized by the algorithm have fast tracking performance and anti-interference ability than the traditional PI controller and the designed H∞ controller,and the simulation results show the feasibility of the design.