Dynamic Characteristics Analysis And Optimization Design Of Speed-increasing Gearbox For High-power Wind Power Generator

With the problem of energy shortage becoming more severe, the wind power has drawn more attention and been widely utilized, the wind power technology has developed quickly. As the key components of wind turbine, the stability and reliability of gear transmission system affects the operation of the whole wind power system. Considering the time-varying load conditions and high erection, dynamic characteristics analysis under varying load and dynamic optimization design of gear transmission system become an important task during the design of wind turbine.One type of3.0MW wind turbine gear transmission system is considered as the research object. Dynamic characteristics of the gear transmission system are analyzed and optimized based on the theory of gear dynamics, numerical method and optimization technique. It has provided the method and theoretical foundation for the design of low vibration and lightweight gear transmission system. Here are the main contents:(1) The lumped parameter method is employed to establish the bend-twist-axis coupled nonlinear dynamics model of the gear transmission system. The model is established after comprehensive considering the factors associated with time-varying mesh stiffness, dynamic transmission error, supporting stiffness, flexibility of planet carrier and damping. The differential equations of the system are derived by analyzing the relative displacement relationship between each component. Meanwhile, the parameters in the equations are analyzed in details.(2) The natural characteristics of the system and their sensitivities to parameters are analyzed. The characteristics of each vibration mode are summarized and the vibration modes can be classified into four categories:vibration mode for three stages, radial translation mode for single planetary stage, planet vibration mode and parallel shaft gear vibration mode. The sensitivities of natural frequencies to the parameters of stiffness and mass are studied.(3) The dynamic responses of the transmission system under the interactions of internal and external excitations are studied. External varying load is determined based on the random wind simulated by ARMA model. Numerical method is employed to solve the dynamics equations, the dynamic responses of the system under constant and time-varying input torque are obtained, which contain the vibration displacements of gear and dynamic meshing load response in both time and frequency domain. The two results are compared and the effect of parameters on the dynamic responses of the system is analyzed.(4) Multi-objective and dynamic optimization design of the transmission system is carried out. The dynamic optimization design model of the transmission system is built after taking the reliability and strength requirements as constraints, which aims at minimizing the peak value of torsional vibration acceleration and volume of the system. With the help of the optimization toolbox in MATLAB, the optimum design is accomplished. The optimization results show that the objective of reducing vibration level and making volume lightweight is achieved.