Coupling Vibration Analysis And Optimum Design Of The Gear Drive System In Megawatt Level Wind-driven Generator

As the rapid development of regenerative energy market, wind power generation gradually becomes a new point of growth in energy industry. The speed increase gearbox of wind-driven generator is an important mechanical part. With the wind generating sets become larger, the function of more stability and high efficiency are required in gear speeder. Due to the randomness of wind velocity, the gear train works long-term under the complex alterate load. Then the vibration of gear transmission system was generated, which will cause fatigue in gear system, reduce the reliability of wind generating equipments, and increase the workload in maintenance. In order to decrease gearbox failures caused by vibration, increase reliability of wind turbine generator system, and raise the homemade level of wind turbine element of our country, which needs to emphasize the dynamic design approach to wind turbine gear speeder.Through the coupling vibration analysis of the gear transmission system of the 1.5 MW wind turbine gearbox, considering the influence of wind load variation and time-varying meshing stiffness in gear pair, the torsional vibration model of gear drive system was established. The system numerical response in time domain and analytic solution was figured out. According to the analytic solution, the object function of dynamic optimum design was obtained. In addition, the mathematical model of optimum design which aims at minizing the vibration and mass of gear train was established, and the ideal parameter of gear system was acquired.This dissertation mainly did following work:â‘ The lumped parameter method was applied to establish the dynamic model of gear drive system, which considered the time-varying meshing stiffness, system damping and the wind load. According to this model, Lagrange's equation was used to derive the torsional oscillatory differential equation of gear system.â‘¡Various solving methods was analyzed and compared, then the four-order Runge-Kutta integration method was utilized to calculate the time domain response of the system before and after optimization, and the optimum design results was evaluated accordingly.The harmonic balance method was adopted to find the analytic solution of system. Above work is favorable for the dynamic design of transmission system.â‘¢After analyzing the optimum design theory about model building, select number of teeth, modulus and transmission ratio as the design variable, the optimum design model of transmission system of speed-up gearbox was set up, which aims at minimizing the value of vibration acceleration of planet gear and the total mass of gear drive system.â‘£w ith the help of MATLAB software and its optimization toolbox,optimum design was accomplished. Compared with the initial results, the total mass of gear train has been decreased, the primary natural frequency of gear system has been obviously raised and the dynamic characteristic has been remarkably improved.Above mentioned could provide a reference with the design of gearbox in wind turbine, which will reduce its weight, cost, vibration and noise.