Studies On Dynamic Characteristics Of Wind Turbine Geared Transmission System With Interval Uncertain Parameters

Uncertainties exist in the geared system of wind turbine due to various factors, such as machining error, assembling error, defect in material and wear.Uncertainties of wind turbine gear transmission system are serious due to uncertain input load induced by random wind, nonlinear time-varying internal excitations caused by time-varying mesh stiffness and backlash, and multi-stage gear transmission. Traditional stochastic methods and fuzzy methods are difficult to deal with such uncertain dynamics owing to lack of information and high cost for obtaining samples. In contrast, the interval method is a relatively newly-developed uncertain method. Less information is required to describe the uncertain parameters. Therefore, the method can deal with uncertainties under scarcity of sample information. This dissertation develops the uncertain analysis methods for wind turbine gear transmission system based on the theory of interval mathematics. The application of the uncertain anlaysis in the nonlinear dynamics of wind turbine gear transmission system is also studied.1) The interval mathematical theory is introduced to uncertain analysis of wind turbine geared system. An uncertain analysis method based on interval is proposed for general geared systems. A wind turbine geared system with torsional vibration is taken as an example to validate the method.2) The above method is expanded to investigate the dynamic responses of wind turbine geared system under stochastic wind excitation and interval parameters. The governing equations for a typical wind turbine gear transmission system subjected to transmission errors, periodic mesh stiffness and random wind excitation are established. The effects of uncertain parameters on dynamic responses of system are also studied. It is shown that the uncertain stiffnesses of the planetary gear stage only have effects on the amplitudes around mesh frequency of the planetary gear stage. The dynamic responses of the intermediate and high-speed stages are all sensitive to uncertain stiffnesses of the intermediate and high-speed stages.3) The interval multi-dimensional harmonic balance method is proposed forsolving nonlinear dynamic equations of the parametrically excited system with multi-frequency excitations and interval parameters. The effects of uncertain parameters on responses of the nonlinear system are studied. The results show that this method keeps the accuracy of the interval method, and effectively improve the computational efficiency.4) The experimental study on dynamic characteristics of a single stage gear transmission system is conducted. In order to compare with experimental results,the theoretical analysis of the test rig is also presented. Theoretical and experimental results show good agreement.The research results will be of significant importance for the performance and reliability of the wind power equipment.