Axial flow fan vibration signal sub-component extraction method based on inverse short-time fourier transform

A short-time Fourier and axial flow fan technology, applied in the field of signal processing, can solve the problem that the accuracy of the signal cannot be guaranteed, and achieve the effects of high-efficiency conversion, fast operation speed, and simple algorithm

Inactive Publication Date: 2018-10-26
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the patent uses Fourier transform and its inverse transform to detect the shaft speed of wind power gearbox at all levels, it is not used in the prior art to extract the subcomponents of the vibration signal of the axial fan and detect the axial fan failure, and the accuracy of the signal obtained during inverse transformation cannot be guaranteed

Method used

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  • Axial flow fan vibration signal sub-component extraction method based on inverse short-time fourier transform
  • Axial flow fan vibration signal sub-component extraction method based on inverse short-time fourier transform
  • Axial flow fan vibration signal sub-component extraction method based on inverse short-time fourier transform

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Embodiment 1, the situation of stationary signal simulation

[0054]S01, set the simulation signal: x=80sin(2π·60t)+50sin(2π·100t)t is the time, in this example from 0 to 1 second, the sampling frequency is 1000, the length is 1000, and the number of sampling points N in the frequency domain is 1024 ;

[0055] S02, make the time domain, frequency domain and time-frequency diagram of the signal, STFT parameters: window length win=100, overlap rate 0.5, overlap length overlap=50, see figure 2 ;

[0056] S03, constructing a zero vector Z, calculating the amplitude correction coefficient h=win-overlap;

[0057] S04, input the corresponding parameters, and completely restore the original signal according to the time-frequency diagram, the algorithm result is as follows image 3 shown. The dotted line signal is the original signal, the solid line signal is the reconstructed signal, and ρ is the correlation coefficient;

[0058] S05, the specified time period is between ...

Embodiment 2

[0065] Embodiment 2, frequency conversion signal simulation situation

[0066] S01, set chirp signal,

[0067] x=80sin(2π·60t+π·10t 2 )

[0068] The parameters are the same as those in the simulation case 1, and the time-frequency diagrams in the time domain, frequency domain and short-time Fourier transform are made, as shown in Figure 7 shown;

[0069] S02, input the corresponding parameters, restore the reconstructed signal in the complete time and frequency segment according to the time-frequency diagram, such as Figure 8 Shown; the dotted line signal is the original signal, the solid line signal is the reconstructed signal, and ρ is the correlation coefficient;

[0070] S03, input the corresponding parameters, set the frequency range to 100-150HZ, and make a reconstructed signal diagram, such as Figure 9 As shown; the dotted line signal is the original signal, and the solid line signal is the reconstructed signal. It can be seen that the signal is roughly within 0...

Embodiment 3

[0071] Embodiment 3, the vibration data of actual fan

[0072] S01, collect the vibration data of a section of the actual operation of the fan. It is known that the rotation frequency of the fan is 20HZ, and the sampling interval is 0.2ms;

[0073] S02, perform wavelet noise reduction processing on the signal, and make its time-domain diagram, frequency-domain diagram and time-frequency diagram after short-time Fourier transform, such as Figure 10 shown;

[0074] S03, input the corresponding parameters, view the reconstructed signal in the complete time and frequency band, and reconstruct the signal according to the time-frequency diagram, such as Figure 11 Shown; the dotted line signal is the original signal, the solid line signal is the reconstructed signal, and ρ is the correlation coefficient;

[0075] S04, input the corresponding parameters, set the viewing time period to 0.6 to 1.6s, and the frequency period to 10 to 25HZ, the algorithm results are as follows Figur...

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Abstract

The invention provides an axial flow fan vibration signal sub-component extraction method based on inverse short-time fourier transform. The axial flow fan vibration signal sub-component extraction method comprises that short-time fourier transform is performed on an axial flow fan vibration signal through a window function, an original waveform graph, a frequency domain graph and a time frequencygraph of the axial flow fan vibration signal are made, wherein the time-frequency diagram is subjected to short-time fourier transform, and corresponding parameters are obtained; a zero vector Z is constructed to serve as a reconstructed signal, the number zero vector Z is constructed to serve as a reconstructed signal, the number coln of the window function is calculated, an amplitude correctioncoefficient B is calculated and the length (Z)of the zero vector Z is calculated; inverse transformation is carried out on a short-time fourier transform matrix S, the returned reconstructed signal Zis obtained, and a time-domain waveform graph is reconstructed from the time frequency graph; and the time t and the graph of the returned reconstructed signal Z are obtained, and a vibration signalsub-component of an axial flow fan is obtained. The method can effectively extract the sub-component of the vibration signal of the axial flow fan, and can be applied to fault detection of the axial flow fan.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to a method for extracting subcomponents of vibration signals of an axial flow fan based on inverse short-time Fourier transform. Background technique [0002] The fan is a machine that relies on the input mechanical energy to increase the gas pressure and discharge the gas. When the impeller of the axial flow fan rotates, the gas enters the impeller axially from the air inlet, and is pushed by the blades on the impeller to increase the energy of the gas. , and then flow into the guide vane. The guide vanes change the deflected airflow into axial flow, and at the same time introduce the gas into the diffuser tube, further convert the kinetic energy of the gas into pressure energy, and finally introduce it into the working pipeline. The vibration of the bearing part is very small at the beginning of operation, but as the operation time increases, the dust in the fan will adhere to t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F04D27/00
CPCF04D27/001
Inventor 初宁张安格黄乾汪国阳吴大转
Owner ZHEJIANG UNIV
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