Research On ADRC Pitch Control Of Wind Turbine And Hardware-in-Loop Simulation

Vigorously developing and utilizing new energy represented by wind power is one of the important measures to solve energy and environmental problems.However,the strong randomness and intermittentity of wind power make it difficult to control the wind power generation system.With the continuous increase of wind turbine capacity as well as moment of inertia of wind wheel,it is more difficult to overcome the fluctuation of output caused by wind disturbance.For variable-speed variable-pitch doubly-fed wind turbine,the main type of wind turbine currently in use,a higher performance of pitch control is required.To solve the problem of strong nonlinearity and large moment of inertia of wind turbine and to achieve goals as suppressing random disturbance of wind conditions effectively and improving power output smoothness of wind turbine in high wind speed zone,a pitch control strategy based on aerodynamic torque feedback by using LADRC technology is designed in this paper.Nowadays,computer control systems such as DCS and PLC are used in almost all practical projects.Considering the practicability,the design and implementation method of discrete LADRC control strategy is systematically studied in this paper,and a hardware-in-loop simulation platform based on PLC,which can verify the performance of the controller more realistically and effectively is further established.The main work of this thesis is as follows:·Taking variable-speed variable-pitch doubly-fed wind turbine as research object to solve the problems of strong non-linearity of wind turbine,frequent wind disturbance and large moment of inertia of wind wheel.The characteristics of variable feedback of pitch control are studied,and the variables related to the power output,which are little or no affected by the moment of inertia are analyzed and selected.The dynamic characteristics of the controlled object are simplified to some standard form by ADRC theory.The complexity and uncertainty of the dynamic characteristics except the standard form are estimated and compensated as disturbance.The standard form is controlled so that the control strategy is not affected by or less affected by the moment of inertia.The LADRC pitch control strategy based on the aerodynamic torque feedback is proposed in this paper·The speed feedback LADRC controller and aerodynamic torque feedback LADRC controller are respectively simulated.The simulation results show that both LADRC controllers have good robustness and ability to suppress wind disturbances under step wind or turbulent wind.The response speed of aerodynamic torque feedback LADRC controller is faster and the power output is more smooth,which can effectively overcome the impact of large moment of inertia.·The design method of discrete controller,modeling method of discrete system and realization method of discrete ESO are systematically studied in order to realize the designed control strategy in computer control system.The influence of different methods on sampling period,model accuracy,observation delay,control performance and their complexity are analyzed.Discrete LADRC pitch controllers with high discretization accuracy and no observation sampling delay is established,and it is programmed in ST language in PLC.·A hardware-in-loop simulation platform based on PLC,which has the function of combining high-precision GH Bladed wind turbine model and wind state model with real PLC system for simulation test is established in order to make the designed control strategy closer to the practical engineering.The performance of the simulation platform is improved by setting different executing period of the wind turbine model and PLC as well as designing initial value tracking mode for the position type discrete LADRC controller.The simulation test of LADRC pitch control strategy is carried out on this platform,and the performance of the controller is verified.