The invention provides a wind
turbine generator transmission chain fault diagnosis method based on time-frequency plane expectation maximization, and belongs to the technical field of fault diagnosis. The method comprises the following steps that a cylindrical MEMS acceleration sensor is arranged on a transmission chain of a wind
turbine generator, and vibration signals of the transmission chain of the wind
turbine generator are collected through the cylindrical MEMS acceleration sensor; an unsupervised classification method based on a
spectrogram zero point is adopted, a vibration
signal and a rotating speed
signal during operation of a wind turbine generator are collected, short-time
Fourier transform is used for generating time-frequency representation for the vibration
signal, the
spectrogram zero point is extracted, unsupervised classification is carried out, and
noise reduction
processing of the vibration signal is achieved; based on a multi-component signal
estimation method under time-frequency plane expectation maximization, the instantaneous frequency and the
instantaneous amplitude of a multi-component signal are accurately estimated on a
time domain plane of the denoised signal; and order
spectrum analysis is carried out, vibration signal characteristics of the wind turbine generator transmission chain are identified, and fault diagnosis of the wind turbine generator transmission chain under the variable rotation speed is realized.