Meshing frequency and spectrum correction technology based wind power gear box order tracking method

Abstract

The invention discloses a meshing frequency and spectrum correction technology based wind power gear box order tracking method. The meshing frequency and spectrum correction technology based wind power gear box order tracking method comprises performing discrete sampling on vibration acceleration signals on the surface of a box body of a fan planet gear box to obtain a non-stationary time domain sequence xn (t); adding a hanning window w (t) to intercept a section of xn (t) and performing FFT (Fast Fourier Transformation) to obtain a power spectrum G (f); performing frequency correction on the meshing frequency fm of a gear box high-speed shaft in the G (f) by a four-point energy centrobaric correction method to obtain an instantaneous meshing frequency which is expressed by the formula; moving window functions in turn and extracting the formula by the energy centrobaric method repeatedly to obtain a meshing frequency curve which is expressed by the formula; obtaining a high-speed shaft rotating frequency curve according to the relation between the meshing frequency and the rotating frequency, wherein the high-speed shaft rotating frequency curve is expressed by the formula; combining with the formula to performing equal-angle resampling on the xn (t) to obtain a smooth angle domain sequence theta n (t); performing correction on the order time and the amplitude by a window length moving method and the energy centrobaric method to obtain an order tracking curves Oi (t). The meshing frequency and spectrum correction technology based wind power gear box order tracking method is good in generality, high in anti-noise performance and accurate and reliable and the problems that a method for measuring the fan rotating speed through a tachometer is difficult in installation, high in cost, poor in accuracy and the like can be avoided.

Description

technical field [0001] The invention relates to the fields of power machinery and signal processing, in particular to an order tracking analysis method for wind power gearboxes using meshing frequency and discrete spectrum correction technology, and is a calculation order tracking analysis method based on vibration acceleration signals that does not require a tachometer. Background technique [0002] The essence of order analysis is to convert the non-stationary signal in the time domain into a stable signal in the angle domain through constant angle incremental sampling. Its core is to obtain equiangular sampling data relative to the reference axis. i (t) and the instantaneous frequency f i (t) correspondence, such as formula (2-1), to accurately obtain the order sampling time (time scale) and the corresponding reference speed (or rotation frequency). [0003] no i (t)=60×f i (t) (2-1) [0004] At present, there are two main types of order tracking analysis methods: one...

AI Technical Summary

Problems solved by technology

[0008] (1) Formula (2-2) only has a clear physical meaning for single-component signals, while actual engineering signals are generally multi-component signals, which are only applicable when the components can be separated on the time-frequency plane, and the versatility is poor

[0009] (2) Using the peak search method to extract the instantaneous frequency of each component from the time-frequency distribution of the multi-component signal, the estimation accuracy is limited by the frequency resolution; when the frequency resolution is low, the phenomenon of finding the wrong instantaneous frequency will occur

[0010] (3) Due to the energy leakage caused by time domain windowing truncation and frequency domain discretization, the Fourier transform frequency result has a maximum error of 0.5 frequency resolution, which affects the accuracy of instantaneous frequency estimation

[0011] (4) The anti-noise performance of this method is poor, and the instantaneous frequency estimation accuracy is not high under noise interference;

[0012] (5) There are many frequency components in the measured wind power gearbox vibration signal, the rotational frequency components of each axis are not obvious, and the signal-to-noise ratio is low, so it is difficult to directly extract the instantaneous rotational frequency

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