随机风载作用下风力发电机齿轮传动系统动态可靠性分析

运用最小二乘支持向量机(Sparse least squares support vector machines,SLS-SVM)机器学习方法建立风场随机风速模型,根据随机风速模型和空气动力学理论得到随机风引起的系统外部载荷激励,建立考虑齿轮时变啮合刚度和滚动轴承时变刚度的风力发电机行星齿轮传动系统齿轮—轴承耦合动力学模型,并对动力学模型进行仿真计算,分别得到各齿轮副的动态啮合力和滚动轴承动态接触力。以此为基础,将载荷作用过程视为随机过程,推导出随机载荷作用下的等效载荷累计分布函数。根据应力—强度干涉理论建立风力发电机齿轮传动系统各齿轮和轴承的动态可靠性模型,利用二阶矩和摄动方法求出各齿轮、轴承的动态可靠性指标,并计算出动态可靠度,研究各齿轮、轴承和传动系统的动态可靠度随时间的变化规律,为风力发电机齿轮传动系统动态可靠性设计奠定了基础。

Time-dependent Reliability Analysis of Gear Transmission System of Wind Turbine under Stochastic Wind Load

The sparse least squares support vector machines(SLS-SVM) is used to simulate wind speed of true wind field,and time-varying wind load caused by stochastic wind speed is then obtained based on the aerodynamics theory.A coupling gear-bearing dynamic model of planetary gear system of wind turbine is built by using lumped-parameter method,the model includes time-vary mesh stiffness of gear pair and time-vary stiffness of rolling element bearing.Numerical method is used to simulate the planetary gear system,and the dynamic meshing forces of each gear pair as well as dynamic bearing forces of each bearing are obtained.Then the load varying process is taken as a random process,the cumulative distribution function of equivalent load under the random load is derived.The time-dependent reliability model of the gears and the bearings in transmission system of wind turbine is established by using the stress-strength interference theory,and the dynamic reliability index and dynamic reliability of the gears and the bearings are obtained by using order-second moment method and perturbation method,and then the time related reliability variation laws of the gears and the bearings as well as the transmission system are studied.The research results lay a foundation for dynamic reliability design of gear transmission system of wind turbine.