Study On Dynamic Behavior Of MW-class Wind Turbine Generation System With Doubly Fed Asynchronous Generator

A modern wind turbine is a complex coupled system, involving multi-physical fields. Based on some relevant standards and guidelines, the work establishes the co-simulation model for the MW-class wind turbine generation system to deeply research its dynamic characteristics under the different conditions by MATLAB/SIMULINK and SIMPACK software. In order to build the model, multibody dynamic modeling method, electrical machine and some control theories are adopted. The work analyzes the vibration of the wind turbine in the conditions of turbulent wind and the change of wind direction. The possible resonance points are obtained, considering the excitation of the generator's electrical torque. In addition, the effects of the differences between pitch angles on the pitch bearings are calculated under the gust condition. The research has important practical value and theory meaning for wind turbine's modeling, simulation and optimization.The main contents and the achievements of the work are as follows:(1) Based on multibody system dynamics and GL2010 guidelines, dynamic model of the wind turbine is built and its modes are calculated by using SIMPACK software.(2) Based on the transient mathematic model of the doubly fed induction generator(DFIG) and the stator-flux vector control theory, the DFIG idling and connected grid models are established by using MATLAB/SIMULINK software. The DFIG and control system models are verified by simulation results.(3) Based on co-simulation technology and pitch and yaw control theory, the cosimulation model of the wind turbine is built. The turbulent wind model, the gust model, the wind direction model and the power grid voltage model are established according the wind turbine's levels.(4) Analyzed the vibration responses of the wind turbines under the turbulent wind and the change of the wind direction conditions.(5) Analyzed the possible resonance points of the drivetrain of the wind turbine considering the excitation of the generator electrical torque. The results show that the excitation cannot be ignored.(6) Analyzed the effects of the differences between the pitch angles on the pitch bearings are calculated under the gust condition. The results show that the load distributions, the contact angles and the life of the pitch bearings will be influence.