Feature extraction method of wind turbine based on adaptive Morlet wavelet and SVD

Abstract

Analyzing the vibration signals of wind turbine usually requires feature extraction. However, in many cases, to extract feature components becomes challenging and the applicability of information drops down due to the large amount of noise. In this paper, a new denoising method based on adaptive Morlet wavelet and singular value decomposition (SVD) is applied to feature extraction for wind turbine vibration signals. Modified Shannon wavelet entropy is utilized to optimize central frequency and bandwidth parameter of the Morlet wavelet so as to achieve optimal match with the impulsive components. The time-frequency resolution can be adapted to different signals of interest. Then, an improved matrix construction method is used to construct matrix of the wavelet coefficient, and the scale periodical exponential (SPE) spectrum is obtained by SVD for selecting the appropriate transform scale. Experimental analysis and application into signal denoising indicate that the proposed method has better denoising performance than other wavelet transforms. The results of the experimental analysis in rolling bearing and the application in planetary gearbox show that the proposed method is an effective approach to detecting the impulsive feature components hidden in vibration signals and performs well for wind turbine fault diagnosis.