Fault diagnosis of wind turbine bearing using synchrosqueezing wavelet transform and order analysis

In this study, a two-steps method is proposed to diagnose the wind turbine bearing fault under the variable speed condition without using a tachometer. In the first step, the synchrosqueezing wavelet transform is used to process the bearing vibration signal to extract the rotating phase from the time-frequency plane. In the second step, the original time-domain vibration signal is resampled according to the extracted rotating phase, and then the bearing fault indicator can be recognized in the envelope order spectrum for fault diagnosis. The effectiveness of the proposed method is validated on a direct-drive wind turbine test rig in which a fault bearing is installed on a permanent magnet synchronous generator.