Dynamic analysis of wind turbine gearboxes with unknown‐but‐bounded parameters under random wind excitation

Dynamic analysis of the gearbox system plays a significant role in wind turbine fault diagnosis. The dynamic behaviour of the gearbox system may be affected by the unavoidable uncertainties of system parameters and external excitations. The dynamic characteristics of the wind turbine gearbox system with uncertainties subjected to random wind excitation are studied. A lumped‐parameter model of a multistage gearbox system under transmission errors, time‐varying mesh stiffness and random wind excitation is established. By using the Chebyshev inclusion function and the Welch method, an interval method for predicting the interval bounds of power spectral density for system responses is proposed. The accuracy of the presented method is verified by comparing with the scanning method. As an example, the effects of different uncertain parameters on the stochastic responses of system are investigated. The result illustrates the effectiveness of the proposed method. It is also shown that the dynamic responses of the system are sensitive to the uncertain stiffness parameters at the intermediate and high‐speed stages. The result is of significant importance for the fault diagnosis in the wind turbine drive train.