Research On Simulation Strategy Of Dynamic Characteristics Of Wind Turbine

The field experiment of the actual wind turbine has the defects of high cost,high risk and inflexible adjustment of wind turbine parameters.The wind turbine simulation system in the laboratory uses a motor to replace the actual wind turbine to drive the generator,which can effectively solve the above problems.Due to the large difference between the moment of inertia of the simulated motor and the actual wind turbine,the dynamic process of the two systems will deviate when the wind speed or generator torque(load torque)changes.Therefore,it is necessary to study the dynamic simulation strategy to improve the accuracy of the simulation system.This paper mainly optimizes two traditional wind turbine dynamic characteristic simulation strategies based on acceleration feedback and load torque feedback.The main defect of the simulation strategy based on acceleration feedback is that there is a one-step delay in the acceleration feedback,which leads to the poor stability of the simulation system.Usually,a filter needs to be connected in series in the feedback loop to maintain the stability of the system,but at this time,the simulation accuracy of the system decreases.To solve the above problems,this paper proposes an improved simulation strategy integrating model predictive control(MPC),and analyzes the stability and accuracy of the improved simulation system.This strategy can suppress the electromagnetic torque fluctuation of the simulated motor when the wind speed changes suddenly,weaken the influence of the acceleration circuit on the system stability,and improve the simulation accuracy.The simulation strategy based on load torque feedback is derived from the principle of equal acceleration between the simulation system and the wind turbine system,but this method ignores the dynamic process simulation deviation caused by the speed error of the two systems.To solve this problem,this paper proposes an improved simulation strategy of speed error compensation,and analyzes the stability and accuracy of the improved simulation system.The results show that the simulation strategy can make the simulation system reproduce the dynamic change process of wind turbine more accurately when the wind speed and load torque change.In the simulation strategy based on load torque feedback and speed error compensation,it is necessary to obtain the electromagnetic torque of the generator in real time.Therefore,this paper studies two high-performance load torque observers,which not only increases the independence between the generator and the analog motor,but also ensures the acquisition accuracy of the generator torque.Finally,the MATLAB / Simulink simulation model of wind turbine simulation system and the semi-physical simulation platform are built.The two improved simulation strategies are simulated and verified by experiments.The results prove the correctness of the theoretical analysis.