Method and system for accurately identifying main frequency of vibration signal

Abstract

The invention discloses a method and a system for accurately identifying the dominant frequency of a vibration signal, and the method comprises the steps: carrying out the sampling of the vibration signal at a frequency fs, and obtaining an AD conversion data sequence of a measured signal; setting a Fourier time window length k to intercept a data sequence, and compressing the sequence length to a fixed length N (N = 4n) by adopting a linear interpolation compression algorithm so as to perform Fourier transform; according to the Fourier transform result, using the side-main ratio of the point with the maximum amplitude in the spectrogram as the result ratio (k) of the calculation, and the smaller the ratio (k) is, the more accurate the calculation of the corresponding main frequency point is; and quickly searching the optimal solution k0 of the function ratio (k), namely the minimum value of the ratio (k), by adopting a branch and bound method, at the moment, k0 is closest to the integral multiple of the number of periodic sampling points of the dominant frequency, and calculating the dominant frequency and the amplitude of the measured signal by applying k0 and dominant frequency position information. According to the method, the problem of inaccurate signal frequency estimation caused by frequency leakage and frequency trailing effect in vibration signal frequency identification can be effectively solved, and the main frequency of the measured signal and the amplitude of the signal spectrum can be accurately identified.

Description

technical field [0001] The invention relates to the field of digital signal processing, in particular to a method and system for accurately identifying the main frequency of a vibration signal. Background technique [0002] As an important task in the field of digital signal processing research, signal frequency identification has significant engineering application value. It has important applications in the fields of non-intrusive internal combustion engine speed measurement, mechanical fault feature extraction, and power grid harmonic monitoring. Signal frequency identification can be divided into parametric method and non-parametric method according to whether to establish a mathematical model for the measured object. Among them, the non-parametric method does not need to establish a specific mathematical model and has good adaptability. The problem of poor recognition accuracy and large amount of calculation; the parametric method establishes a mathematical model for ma...

AI Technical Summary

Problems solved by technology

[0008] This application provides a method for accurately identifying the main frequency of the vibration signal, which solves the problems of low identification accuracy, slow speed and large error caused by frequency leakage.

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