Research On Frequency Modulation Control Of Wind-storage Combined System Based On VSG

In recent years,with the proposal of the " carbon peaking and carbon neutrality " strategy and the acceleration of the construction of new power systems,wind power has ushered in a new round of development opportunities.However,the access of large-scale wind power has brought great challenges to the frequency stability of the power system.The direct-drive permanent magnet fan using the traditional control method does not have the ability to actively participate in the frequency regulation of the power system,which is not conducive to the frequency stability of the power system.Therefore,this paper takes the direct-drive permanent magnet wind turbine as the research object,and conducts research on the frequency regulation control of wind turbines and the participation of the wind-storage combined system in power grid frequency regulation.The main work is as follows:(1)In view of the problem that the direct-drive permanent magnet fan does not have the ability to actively participate in the frequency regulation of the power system,this paper establishes a system mathematical model on the basis of analyzing the working principle of the direct-drive permanent magnet fan,and studies the technology based on the virtual synchronous generator technology.The control strategy of the wind turbine converter is analyzed,the operation stability and frequency regulation characteristics of the wind turbine under different wind conditions are analyzed,and the feasibility of the virtual synchronous generator control of the wind turbine is verified by simulation,which lays the foundation for the follow-up research of this paper.(2)Aiming at the problem of poor fan frequency regulation performance caused by the fixed inertia and fixed damping in the traditional virtual synchronous generator rotation equation,a nonlinear adjustment method of virtual synchronous generator parameters based on Elman neural network is proposed,which further improves the virtual synchronous generator.The frequency regulation capability of the generator.In this paper,the influencing factors of the stability and dynamic response of virtual synchronous generators are analyzed,the principle of parameter selection is obtained,and the parameter adjustment method is designed.(3)Aiming at the problem of insufficient frequency regulation capability of wind turbines,a wind-storage joint frequency regulation control method based on model predictive control is proposed.In this paper,a wind-storage integrated control framework is established based on model predictive control,and the advanced control characteristics of model predictive control are used to overcome the inherent lag effect of virtual synchronous generators.At the same time,the control objective function is set according to different wind speed conditions,and the frequency regulation capability evaluation and dynamic regulation system is constructed,which realizes the coupling and complementation of the frequency regulation characteristics of the wind turbine and the energy storage,and makes full use of the frequency regulation resources of the system.Finally,the superiority of the proposed control strategy in ensuring the stability of the fan and improving the frequency regulation capability of the fan is verified by simulation.