关键词: 风力发电机, 传动系统, 机电耦合, 动态特性, 运行控制

Abstract: To reveal the electromechanical coupling dynamic characteristics of the wind power transmission systems under the variable speeds and variable load operation conditions， the electromechanical coupling model of the wind power transmission systems including the gear system dynamics model， the finite element model of permanent magnet synchronous generator and the operation control model of wind turbine was established， taking into consideration of the nonlinear factors such as gears time-varying meshing stiffness， cogging effect and magnetic saturation of generators. The dynamic responses of the systems under the starting and power generation operation conditions and the electromechanical coupling dynamic characteristics of the system were analyzed. The results show that the dynamic responses of the wind power transmission systems are stable under the starting condition； under the power generation operation condition， the wind power transmission systems are under a variable speed and variable load state， and low-frequency torsional vibrations are vulnerable to be excited and dynamic responses are complicated. Under the effects of generator cogging， magnetic saturation and other factors， the currents and electromagnetic torques may produce main harmonic frequency fluctuations caused by time harmonics and space harmonics. Because of the electromechanical coupling effects， the gear vibration characteristics and the electromagnetic characteristics may affect each other. The currents and electromagnetic torques contain more mechanical vibration frequency components related to gear meshing. At the same time， the electromagnetic torques react to the gear systems， which excites rich structural frequency components of the gear systems. 

Key words: wind turbine, transmission system, electromechanical coupling, dynamic characteristic, operation control