随机风速下风电传动系统机电耦合动态特性分析

ELECTROMECHANICAL COUPLING DYNAMIC CHARACTERISTIC ANALYSIS OF WIND TURBINE TRANSMISSION SYSTEM UNDER RANDOM WIND SPEED

综合考虑时变啮合刚度、齿侧间隙等时变、非线性因素,采用集中参数法建立适用于变速工况的风电传动系统扭转动力学模型,并结合发电机矢量控制、叶片变桨运行控制,形成风力发电机传动链机电耦合模型。通过数值方法对模型进行求解,研究系统的固有振动特性和随机风速下的动态响应特性,揭示风电传动链中机械系统与电气系统间的相互影响规律。结果表明:该风电传动系统在风速扰动下易被激起由一阶模态主导的低频扭振,而电气系统具有阻尼特性,对该扭振产生明显抑制作用。此外,机械系统振动与电磁转矩波动相互作用,振动信号以调制形式出现在电流信号中,信号强弱与振动大小呈正相关性。

Considering time-varying and nonlinear factors such as mesh stiffness,backlash and etc,a torsional dynamic model of wind turbine drive system for variable speed condition is established through lumped-parameter method.Then a electromechanical coupling dynamic model is formed by combining this model with vector control modle of the generator and pitch angle control model of the blade.Numerical method is used to solve the dynamic model,the natural characteristics and the dynamic response characteristics under random wind speed of this system is analyzed,the mutual effect between the mechanical system with the electric system is revealed.The results show that the low-frequency torsional vibration,which is dominated by the first order mode of this system,is vulnerable to be excited under variable wind.And the electric system contains damping characteristics that obviously inhibit the torsional vibration.In addition,since the vibration of mechanical system interacts with the fluctuation of electromagnetic torque,the vibration of the mechanical system can be observed in generator stator current in the form of modulated signal and the signal strength is positively correlated with the vibration magnitude.