Dynamic Modeling And Simulation Analysis Of Large-scale Onshore DFIG Wind Turbine

In recent years,the single-unit capacity of wind turbines has continued to increase,with longer blades and tal er towers,the requirements for system dynamics are getting higher and higher,establishing accurate dynamic models and performing simulation analysis are important aspects of the early design of wind turbines.According to the international general standards GL2010 and IEC614000,the multi-body dynamic model of the rigid-flexible coupling system and the joint simulation control model of the whole machine are established,and the whole machine dynamic model of the wind turbine is studied,which has theoretical and engineering application significance.The main research work of the thesis is as follows:1)According to the aerodynamic characteristics of the wind turbine,the traditional aerodynamic mathematical model of the wind turbine is established.Then,combined with the structure of the wind turbine used in this paper,and using the basic principle of Lagrange dynamic formula,the accurate multi-body dynamic equation of the three degree of freedom transmission chain is established,which lays a theoretical foundation for the dynamic simulation analysis.2)A rigid-flexible coupling multi-body dynamics model was established,and the multi-body dynamics model was analyzed in the frequency domain and time domain.After calculation,the natural frequency and excitation frequency of the model were obtained.The dangerous resonance frequency of the model is found by Fourier Fast Transform principle.3)Based on the operation principle of DFIG,the grid side and machine side vector control schemes are designed respectively.The vector control system of DFIG is carried out.The DFIG model based on vector control is coupled with the traditional pneumatic model,and the pneumatic model including DFIG is established.The model can simulate the operation of wind turbine under ideal wind state and realize pitching simulation,maximum wind energy tracking,grid connection of the DFIG,decoupling control of active and reactive power,etc.4)Coupling the multi-body dynamics model and the vector-controlled doubly-fed motor model to establish a gas-elastic-electromechanical multi-field coupling dynamics model,and propose an independent pitch control system based on load feedback on the basis of the original unified pitch.The model provides a new model and new method to analyze the dynamic load and response of the wind turbine for the simulation research of the wind turbine.It is concluded that the independent pitch control can effectively reduce the yaw and pitch bending moment imbalance of the blade caused by the tower shadow effect.The conclusion has practical engineering application value.