Wind driven generator transmission chain vibration detection method based on echo wall mode microcavity

Abstract

The invention discloses a wind driven generator transmission chain vibration detection method based on an echo wall mode microcavity, and relates to the technical field of wind power generation. The wind driven generator transmission chain vibration detection method comprises the following steps: guiding a laser light source into the echo wall mode microcavity based on an optical fiber coupling technology; a vibration response signal at the position of a transmission chain of the wind driven generator is obtained by using the echo wall mode microcavity; and converting the vibration response signal into a digital signal by using a signal processing technology, analyzing and processing the digital signal by combining a digital signal processor, and obtaining vibration information at the position of the transmission chain of the wind driven generator based on a processing result. According to the wind driven generator transmission chain vibration detection method based on the echo wall mode microsphere cavity, the vibration condition of the wind driven generator transmission chain can be detected and analyzed in a high-precision and high-sensitivity mode, and meanwhile the method has the advantages of being capable of resisting interference and adapting to severe environments.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a method for detecting vibration of a transmission chain of a wind power generator based on a whispering gallery mode microcavity. Background Art

[0002] The transmission chain of a wind turbine includes key components such as the gearbox, main shaft and coupling. Its operating status directly affects the performance and safety of the entire wind power generation system. Abnormal vibration of the transmission chain may be a precursor to a fault. Therefore, real-time monitoring of the vibration of the transmission chain is crucial for preventive maintenance. Vibration detection can capture the status of the gearbox, bearings and other rotating parts in real time, and detect abnormal vibration patterns in time, thereby identifying potential faults and losses. This not only helps prevent unexpected downtime and expensive maintenance costs, but also extends the service life of the equipment and ensures the continuity and stability of wind power generation. Therefore, vibration detection is a core part of the predictive maintenance strategy for wind turbines, which helps to achieve higher safety standards and better economic benefits.

[0003] However, although existing vibration detection methods have been widely used in the wind power industry, they still face a series of limitations. Traditional vibration detection methods, such as accelerometer-based sensors, are reliable in certain environments, but they are usually sensitive to environmental noise and may require complex signal processing to distinguish between background noise and real vibration signals. In addition, these systems may have difficulty adapting to the detection requirements of high-frequency and small vibrations in wind turbines.

[0004] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0005] In view of the problems in the related art, the present invention proposes a wind turbine transmission chain vibration detection method based on whispering gallery mode microcavity to overcome the above technical problems existing in the existing related art.

[0006] To this end, the specific technical solution adopted by the present invention is as follows:

[0007] A wind turbine transmission chain vibration detection method based on a whispering gallery mode microcavity, the wind turbine transmission chain vibration detection method comprising:

[0008] Based on the optical fiber coupling technology, the laser light source is introduced into the whispering gallery mode microcavity, and the whispering gallery mode microcavity is used to obtain the vibration response signal at the transmission chain position of the wind turbine.

[0009] The vibration response signal is converted into a digital signal using signal processing technology, and the digital signal is analyzed and processed in combination with a digital signal processor, and the vibration information at the position of the wind turbine transmission chain is obtained based on the processing result.

[0010] Preferably, introducing a laser light source into a whispering gallery mode microcavity based on an optical fiber coupling technology, and using the whispering gallery mode microcavity to obtain a vibration response signal at a position of a transmission chain of a wind turbine generator comprises:

[0011] Install a whispering gallery mode microcavity at a set position of the wind turbine transmission chain, adjust the laser power using a laser controller, and then turn on the laser to emit a laser light source to the wind turbine transmission chain;

[0012] The laser light source is received by using an optical fiber coupler, and after adjusting the relative position between the optical fiber coupler and the whispering gallery mode microcavity, the laser light source is introduced into the whispering gallery mode microcavity;

[0013] The state information of the laser light source in the whispering gallery mode microcavity is analyzed, and the vibration response signal at the position of the wind turbine transmission chain is obtained based on the state information.

[0014] Preferably, the laser is a continuous wave laser with an output power of 15 mW, and the laser light source is a supercontinuum light source.

[0015] Preferably, analyzing the state information of the laser light source in the whispering gallery mode microcavity, and acquiring the vibration response signal at the position of the wind turbine transmission chain based on the state information comprises:

[0016] The whispering gallery mode microcavity receives the laser light source. Based on the spherical structure of the whispering gallery mode microcavity, the laser light source propagates in the whispering gallery mode microcavity according to the set mode.

[0017] Analyze the state information of the laser light source in the whispering gallery mode microcavity sensor cavity according to the propagation results, and determine the reflection information of the laser light source based on the state information to obtain a closed optical path;

[0018] The mass change of the whispering gallery mode microcavity is analyzed based on the closed optical path, and the resonant frequency change of the laser light source is calculated using the mass change and the preset resonant frequency.

[0019] The vibration at the position of the wind turbine transmission chain is induced according to the change of the resonant frequency, and the vibration response signal of the whispering gallery mode microcavity is obtained by using the vibration sensing result.

[0020] Preferably, the expression for the change in resonant frequency is:

[0021]

[0022] Where Δf represents the change in resonance frequency, f0 represents the resonance frequency of the whispering gallery mode microcavity when it is not affected by vibration, Δm represents the change in the effective mass of the whispering gallery mode microcavity due to vibration, and m0 represents the effective mass of the whispering gallery mode microcavity when it is not affected by vibration.

[0023] Preferably, the vibration response signal is converted into a digital signal by using a signal processing technology, and the digital signal is analyzed and processed in combination with a digital signal processor, and the vibration information at the position of the wind turbine transmission chain is obtained based on the processing result, including:

[0024] The vibration response signal is transmitted through an optical fiber coupler, and the vibration response signal is received by a photodetector, and the vibration response signal is converted into an electrical signal based on a photodiode;

[0025] After the electric signal is amplified by the signal amplifier, the electric signal is converted into a digital signal by using the signal conversion circuit;

[0026] Use a digital signal processor to perform Fourier transform on the digital signal, obtain the spectrum of the digital signal based on the transform result, and design a bandpass filter to combine with the spectrum to generate a filtered signal;

[0027] The nonlinear trend removal technology is used to preprocess the filtered signal, and the signal change amplitude and phase change are analyzed according to the processing results. The vibration information at the position of the wind turbine transmission chain is obtained based on the signal change amplitude and phase change.

[0028] Preferably, using a digital signal processor to perform Fourier transform on the digital signal, obtaining the spectrum of the digital signal based on the transform result, and designing a bandpass filter to combine with the spectrum to generate a filtered signal includes:

[0029] Performing Fourier transform operation on the digital signal using a digital signal processor, and converting the digital signal into a frequency domain based on the transform result to obtain a spectrum of the digital signal;

[0030] Based on the preset lower cutoff frequency and upper cutoff frequency, the frequency range allowed to pass by the bandpass filter is defined, and the frequency range is combined with the frequency variable to design the bandpass filter;

[0031] The digital signal is filtered using a bandpass filter and the spectrum of the digital signal, and an inverse Fourier transform is performed on the digital signal based on the filtering result to obtain a filtered signal in the regression time domain.

[0032] Preferably, the expression of the spectrum of the digital signal is:

[0033]

[0034] In the formula, S(f) represents the spectrum of the digital signal, s(t) represents the digital signal, t represents the time variable, f represents the frequency variable, e represents the conversion factor, j represents the imaginary unit, and d represents the summation of the digital signal in the time variable.

[0035] Preferably, the expression of the filtered signal is:

[0036]

[0037] Where s`(t) represents the filtered signal after inverse Fourier transform regression to the time domain, s(t) represents the digital signal, t represents the time variable, f represents the frequency variable, e represents the conversion factor, j represents the imaginary unit, and d represents the summation of the digital signal in the time variable.

[0038] Preferably, the filtered signal is preprocessed using a nonlinear trend removal technique, and the signal change amplitude and phase change are analyzed according to the processing result, and the vibration information at the position of the wind turbine transmission chain is obtained based on the signal change amplitude and phase change, including:

[0039] Generate a trend curve of the filtered signal based on a nonlinear trend removal technique, and remove the trend curve from the filtered signal to obtain a detrended filtered signal;

[0040] The difference between the maximum value and the minimum value of the filtered signal is obtained to obtain the peak-to-valley amplitude, and the vibration amplitude at the position of the wind turbine transmission chain is determined based on the peak-to-valley amplitude;

[0041] Using the periodic characteristics of the filtered signal, the maximum and minimum periodic values ​​of the filtered signal are estimated, and the vibration frequency at the position of the wind turbine transmission chain is determined based on the periodic difference result;

[0042] A continuous waveform of the filtered signal is obtained, the phase difference of the filtered signal is analyzed according to the phase difference of the continuous waveform, and the vibration phase at the position of the transmission chain of the wind turbine generator is obtained based on the phase difference.

[0043] The beneficial effects of the present invention are:

[0044] 1. The present invention adopts a specially designed whispering gallery mode microcavity structure and optical frequency comb technology to achieve high-sensitivity detection of tiny vibration signals. Compared with the traditional vibration detection method based on acceleration sensor, it can provide high-resolution vibration signal detection in a wider frequency range, and has significant resistance to environmental interference. At the same time, it can provide more sophisticated frequency response analysis, which makes it have obvious advantages in detection accuracy and stability. Therefore, it can not only improve the accuracy of fault detection, but also reduce the cost caused by frequent maintenance or unplanned downtime, and significantly enhance the reliability and economic benefits of wind turbines.

[0045] 2. The present invention realizes high-precision capture of extremely small physical changes in the transmission chain of wind turbines through the whispering gallery mode microcavity sensor, which changes the problem that traditional acceleration sensors are limited by their physical size and sensitivity and cannot detect small or high-frequency vibration signals. It can identify small vibration changes, thus providing the possibility for early fault warning, greatly reducing sudden shutdowns and maintenance costs caused by faults, and improving the reliability and operating efficiency of wind turbines.

[0046] 3. The wind turbine transmission chain vibration detection method based on the whispering gallery mode microsphere cavity provided by the present invention can detect and analyze the vibration of the wind turbine transmission chain with high precision and high sensitivity, and at the same time has the ability to resist interference and adapt to harsh environments. Based on the use of optical whispering gallery mode microcavity sensing technology, it can accurately capture tiny vibrations in the wind turbine transmission chain, thereby monitoring the health status of the equipment in real time, and can warn of possible failures and damages at an early stage, so as to improve the reliability and economic benefits of wind power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 is a flow chart of a method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to an embodiment of the present invention;

[0049] Figure 2 is a schematic diagram of a tapered optical fiber according to an embodiment of the present invention;

[0050] Figure 3 The invention relates to a coupling system of a whispering gallery mode microcavity and a tapered optical fiber according to an embodiment of the invention. DETAILED DESCRIPTION

[0051] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments. They can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in this field should be able to understand other possible implementation methods and advantages of the present invention.

[0052] According to an embodiment of the present invention, a method for detecting vibration of a transmission chain of a wind turbine generator based on a whispering gallery mode microcavity is provided.

[0053] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to an embodiment of the present invention, a method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity comprises:

[0054] Step S1: introducing a laser light source into a whispering gallery mode microcavity based on optical fiber coupling technology, and using the whispering gallery mode microcavity to obtain a vibration response signal at a position of a transmission chain of a wind turbine generator.

[0055] In this embodiment, when a laser light source is introduced into a whispering gallery mode microcavity based on an optical fiber coupling technology, and a vibration response signal at a position of a wind turbine transmission chain is obtained by using the whispering gallery mode microcavity, a whispering gallery mode microcavity can be installed at a set position of the wind turbine transmission chain, and after adjusting the laser power by using a laser controller, the laser is turned on to emit a laser light source to the wind turbine transmission chain; an optical fiber coupler is used to receive the laser light source, and after adjusting the relative position between the optical fiber coupler and the whispering gallery mode microcavity, the laser light source is introduced into the whispering gallery mode microcavity; state information of the laser light source in the whispering gallery mode microcavity is analyzed, and the vibration response signal at the position of the wind turbine transmission chain is obtained based on the state information.

[0056] In this embodiment, when analyzing the state information of the laser light source in the whispering gallery mode microcavity and obtaining the vibration response signal at the position of the wind turbine transmission chain based on the state information, the whispering gallery mode microcavity can receive the laser light source, and based on the spherical structure of the whispering gallery mode microcavity, the laser light source propagates in the whispering gallery mode microcavity according to a set mode; the state information of the laser light source in the whispering gallery mode microcavity sensor cavity is analyzed according to the propagation result, and the reflection information of the laser light source is judged based on the state information to obtain a closed optical path; the mass change of the whispering gallery mode microcavity is analyzed based on the closed optical path, and the resonant frequency change of the laser light source is calculated using the mass change and the preset resonant frequency; the vibration at the position of the wind turbine transmission chain is sensed according to the resonant frequency change, and the vibration response signal of the whispering gallery mode microcavity is obtained using the vibration sensing result.

[0057] Step S2: convert the vibration response signal into a digital signal using signal processing technology, and analyze and process the digital signal in combination with a digital signal processor, and obtain vibration information at the position of the wind turbine transmission chain based on the processing result.

[0058] In this embodiment, when the vibration response signal is converted into a digital signal by using signal processing technology, and the digital signal is analyzed and processed in combination with a digital signal processor, and the vibration information at the position of the wind turbine transmission chain is obtained based on the processing result, the vibration response signal can be transmitted through an optical fiber coupler, and the vibration response signal is received by a photodetector, and the vibration response signal is converted into an electrical signal based on a photodiode; after the electrical signal is amplified based on a signal amplifier, the electrical signal is converted into a digital signal by a signal conversion circuit; the digital signal is Fourier transformed by using a digital signal processor, the spectrum of the digital signal is obtained based on the transformation result, and a bandpass filter is designed to generate a filtered signal in combination with the spectrum; the filtered signal is preprocessed by using a nonlinear trend removal technology, and the signal change amplitude and phase change are analyzed according to the processing result, and the vibration information at the position of the wind turbine transmission chain is obtained based on the signal change amplitude and phase change.

[0059] In this embodiment, when using a digital signal processor to perform Fourier transform on a digital signal, obtaining the spectrum of the digital signal based on the transform result, and designing a bandpass filter to generate a filtered signal in combination with the spectrum, the digital signal processor can be used to perform a Fourier transform operation on the digital signal, and the digital signal can be converted to the frequency domain based on the transform result to obtain the spectrum of the digital signal; the frequency range allowed to pass by the bandpass filter is defined based on a preset lower cutoff frequency and an upper cutoff frequency, and the bandpass filter is designed by combining the frequency range with the frequency variable; the digital signal is filtered using the bandpass filter and the spectrum of the digital signal, and an inverse Fourier transform is performed on the digital signal based on the filtering result to obtain a filtered signal in the regression time domain.

[0060] In this embodiment, when the filtered signal is preprocessed using a nonlinear trend removal technique, and the signal change amplitude and phase change are analyzed based on the processing results, and the vibration information at the wind turbine transmission chain position is obtained based on the signal change amplitude and phase change, a trend curve of the filtered signal can be generated based on the nonlinear trend removal technique, and the trend curve is removed from the filtered signal to obtain a detrended filtered signal; the difference between the maximum and minimum values ​​of the filtered signal is obtained to obtain the peak-to-valley amplitude, and the vibration amplitude at the wind turbine transmission chain position is determined based on the peak-to-valley amplitude; the periodic maximum and minimum values ​​of the filtered signal are estimated using the periodic characteristics of the filtered signal, and the vibration frequency at the wind turbine transmission chain position is determined based on the periodic difference result; the continuous waveform of the filtered signal is obtained, the phase difference of the filtered signal is analyzed based on the phase difference of the continuous waveform, and the vibration phase at the wind turbine transmission chain position is obtained based on the phase difference.

[0061] like Figures 2 to 3The technical solution of this embodiment is further described below in conjunction with the accompanying drawings. The wind turbine transmission chain vibration detection method based on the whispering gallery mode microsphere cavity proposed in this embodiment mainly includes a laser, a whispering gallery mode microsphere cavity, a fiber taper coupler, a photodetector and a signal processor, wherein:

[0062] The laser is a continuous wave laser (CW Laser), selected at 1550nm to adapt to the optical properties of fused quartz, with an output power of 15mW, which is enough to excite the microsphere cavity but not cause thermal effects. The power fluctuation is less than 1% to ensure detection accuracy. It provides a stable light source for exciting the microsphere cavity.

[0063] The whispering gallery mode microsphere cavity is a spherical structure of high-purity fused quartz with a sphere diameter of 500 microns, an accuracy of ±1 micron, and a quality factor (Q factor) of 10 8 , to ensure high sensitivity and low loss. Used to sense vibration and produce optical response.

[0064] The fiber cone coupler includes a fiber cone, a precision adjustment mechanism (micro-motion platform) and a supporting structure, with a coupling efficiency of 30-40%, which can effectively couple the laser into the whispering gallery mode microsphere cavity and collect the output signal of the whispering gallery mode microsphere cavity. The fiber cone is used to efficiently couple the laser into the whispering gallery mode microsphere cavity and couple out the response signal of the whispering gallery mode microsphere cavity. The precision adjustment mechanism allows the precise adjustment of the position between the fiber cone and the whispering gallery mode microsphere cavity to optimize the coupling efficiency. The supporting structure is used to stabilize the device and ensure stability during the coupling process.

[0065] The photodetector includes a photodiode, a signal amplifier, and a signal conversion circuit, which detect the light signal output from the microsphere cavity and convert it into an electrical signal. The photodiode detects the light signal output from the whispering gallery mode microsphere cavity and converts the light signal into an electrical signal. The signal amplifier amplifies the weak electrical signal received from the photodiode, and the signal conversion circuit converts the analog signal into a digital signal for subsequent processing and analysis. It detects the light signal output from the whispering gallery mode microsphere cavity and converts it into an electrical signal. The bandwidth is greater than 1GHz to capture high-speed vibration signals.

[0066] The signal processor includes an analog-to-digital converter (ADC) and a digital signal processor (DSP) for signal processing and analysis.

[0067] As shown in Table 1, in this embodiment, the sensor (whispering gallery mode microsphere cavity) is installed at the following positions:

[0068] Spindle sensor installation location: near the hub at both ends of the spindle to detect vibration caused by blade movement and wind load;

[0069] Gearbox sensor installation location: near the gearbox input shaft (high-speed shaft) to detect the vibration of gears and bearings;

[0070] Generator sensor installation location: near the generator bearing, to detect vibration caused by bearing wear or imbalance.

[0071] Table 1 Detection points of transmission chain

[0072] Measuring point location Measuring point name quantity Spindle front bearing 1H 1 Spindle rear bearing 2A 1 Gearbox first stage planetary gear 3H 1 Secondary planetary gearbox 4V 1 Speed ​​increaser low speed shaft output 5A 1 Speed ​​increaser high speed shaft 6H 1 Generator working end 7H 1 Generator free end 8H 1

[0073] This embodiment performs vibration detection on a Siemens Gamesa SG 8.0-167DD wind turbine. This wind turbine has a rated power of 8.0 MW and is widely used in large offshore wind power. The specific detection steps are as follows:

[0074] Step 1: Install whispering gallery mode microsphere cavity sensors at key locations of the main shaft, gearbox, generator, and tower, turn on the laser power supply to ensure that a stable current or voltage is provided, adjust the power and stability of the laser through the laser controller, ensure that the laser transmitter body produces a single wavelength and stable laser light source, and guide the light emitted by the laser into the whispering gallery mode microsphere cavity through the optical fiber cone.

[0075] During the introduction process, a precision regulator is used to adjust the relative position between the fiber cone and the whispering gallery mode microsphere cavity to optimize the light coupling efficiency and ensure the stability of the device to prevent the coupling efficiency from being affected by vibration or environmental changes.

[0076] The whispering gallery mode microsphere cavity acts as a vibration sensor and responds to external vibration. The vibration causes the resonance characteristics of the whispering gallery mode microsphere cavity to change, and the response signal of the whispering gallery mode microsphere cavity (i.e., the changed optical signal) is transmitted through the fiber taper coupler.

[0077] It should be explained that the laser is a continuous wave laser (CW Laser), selected at 1550nm to adapt to the optical properties of fused quartz, with an output power of 15mW, which is sufficient to excite the whispering gallery mode microcavity but not to cause thermal effects. The power fluctuation is less than 1% to ensure detection accuracy. It provides a stable light source for exciting the whispering gallery mode microsphere cavity, and at the same time uses an optical frequency comb (such as a supercontinuum light source) as a laser source to provide broadband spectral coverage to achieve high-resolution scanning of the whispering gallery mode microcavity.

[0078] The whispering gallery mode microsphere cavity is a spherical structure made of high-purity fused quartz with a size of tens to hundreds of microns to ensure high sensitivity and low loss. Light waves propagate in a specific mode inside the whispering gallery mode microsphere cavity. These modes form standing waves on the boundary of the whispering gallery mode microsphere cavity. The light waves are totally reflected multiple times on the inner surface of the microsphere cavity to form a closed optical path, which is similar to the whispering gallery phenomenon in acoustics. The resonant frequency of the whispering gallery mode microsphere cavity is closely related to its size and shape.

[0079] The change in the size of the whispering gallery mode microsphere cavity caused by vibration will lead to the movement of the resonant frequency. The sensor can sense and respond to the tiny vibrations generated by the wind turbine transmission chain during operation. These vibrations cause extremely small changes in the physical size of the whispering gallery mode microsphere cavity. Since the whispering gallery mode microsphere cavity has a high Q factor, it is extremely sensitive to size changes. Therefore, even a tiny physical change can cause a significant shift in the resonant frequency of the whispering gallery mode microsphere cavity. The whispering gallery mode microsphere cavity sensor is coupled to a tapered optical fiber, and the waist part of the tapered optical fiber produces a strong evanescent field, which can effectively couple with the optical mode of the whispering gallery mode microsphere cavity in the near field. When the resonant frequency of the whispering gallery mode microcavity changes, the coupling efficiency also changes, resulting in a change in the intensity of the optical signal transmitted from the whispering gallery mode microcavity.

[0080] The resonant frequency change is used to sense the vibration and generate the optical response. The resonant frequency change can be expressed as:

[0081]

[0082] Where Δf represents the change in resonance frequency, f0 represents the resonance frequency of the whispering gallery mode microcavity when it is not affected by vibration, Δm represents the change in the effective mass of the whispering gallery mode microcavity due to vibration, and m0 represents the effective mass of the whispering gallery mode microcavity when it is not affected by vibration.

[0083] The fiber-cone coupler includes a fiber cone, a precision adjustment mechanism (micro-motion platform) and a supporting structure, which effectively couples the laser into the whispering gallery mode microcavity and collects the output signal of the whispering gallery mode microcavity.

[0084] The fiber taper is formed by heating and thinning a single-mode optical fiber to a tapered structure. The diameter of the tapered region gradually decreases along the length of the optical fiber, forming a smooth tapered transition zone and a very thin tapered waist. The tapered region is the part of the optical fiber taper where the diameter gradually changes. Its function is to couple light from the large end to the small end of the optical fiber. The length and taper ratio of the tapered region will affect the coupling efficiency and mode conversion. The tapered waist is the thinnest part of the tapered optical fiber, and its diameter can be as small as a few microns. A strong evanescent field will be generated at the tapered waist, which is crucial for the near-field coupling of the whispering gallery mode microcavity.

[0085] In order to optimize the coupling efficiency, the relative position between the fiber cone and the whispering gallery mode microcavity needs to be precisely controlled. The precision adjustment mechanism usually includes a micro-motion platform that allows micron-level adjustment in three spatial dimensions. The support structure is used to stabilize the fiber cone coupling device to ensure stability during the coupling process, specifically including a clamp or bracket for fixing the fiber cone.

[0086] Among them, the fiber cone is used to efficiently couple the laser into the whispering gallery mode microcavity and couple out the response signal of the whispering gallery mode microcavity. The precision adjustment mechanism allows the position between the fiber cone and the whispering gallery mode microcavity to be precisely adjusted to optimize the coupling efficiency. The support structure is used to stabilize the device and ensure stability during the coupling process.

[0087] Step 2: The photodetector receives the light signal output by the whispering gallery mode microsphere cavity, the photodiode converts the light signal into an electrical signal, and the signal amplifier amplifies the weak electrical signal for subsequent processing. In the signal processor, the analog-to-digital converter (ADC) converts the amplified analog signal into a digital signal, and the digital signal processor (DSP) further processes the digital signal, such as filtering, amplification, and noise suppression.

[0088] It needs to be explained that the photodetector includes a photodiode, a signal amplifier, and a signal conversion circuit, which detects the light signal output from the whispering gallery mode microsphere cavity and converts it into an electrical signal. The photodiode detects the light signal output from the whispering gallery mode microsphere cavity and converts the light signal into an electrical signal, wherein the signal amplifier amplifies the weak electrical signal received from the photodiode, and the signal conversion circuit converts the analog signal into a digital signal for subsequent processing and analysis.

[0089] The signal processor includes an analog-to-digital converter (ADC) and a digital signal processor (DSP), which are used for signal processing and analysis. The ADC converts the amplified analog signal into a digital signal, which is a prior art. The DSP performs filtering, amplification, noise suppression and other processing on the digital signal.

[0090] First, the collected digital signal s(t) is Fourier transformed to the frequency domain using signal processing to obtain the signal's spectrum representation S(f):

[0091]

[0092] In the formula, S(f) represents the spectrum of the digital signal, s(t) represents the digital signal, that is, the vibration signal captured in the time domain, t represents the time variable, f represents the frequency variable, e represents the conversion factor, j represents the imaginary unit, and d represents the summation of the digital signal in the time variable.

[0093] And design a bandpass filter H(f) and apply it to the spectrum of the signal:

[0094]

[0095] In the formula, f L Represents the lower cutoff frequency of the filter, f H Indicates the filter cutoff frequency.

[0096] H(f) represents the transfer function of the bandpass filter, which is used to select signal components within a specific frequency range and exclude signals of other frequencies. The filtered signal S'(f) = S(f)H(f) is returned to the time domain through inverse Fourier transform:

[0097]

[0098] Wherein, s`(t) represents the filtered signal after inverse Fourier transform regression to the time domain, that is, the inverse transform result of S'(f), s(t) represents the digital signal, t represents the time variable, f represents the frequency variable, e represents the conversion factor, j represents the imaginary unit, and d represents the sum of the digital signal in the time variable.

[0099] The filtered signal s`(t) is analyzed in the time domain to extract the vibration parameters such as amplitude, frequency and phase. The signal s`(t) is preprocessed as necessary, including denoising, linear or nonlinear trend removal, etc., to improve the accuracy of the analysis.

[0100] And calculate the peak-to-peak amplitude of the signal, that is, the difference between the maximum and minimum values ​​of the signal, to determine the amplitude of the vibration. At the same time, the frequency of the vibration is estimated through the periodic characteristics in the time domain, such as the maximum and minimum values ​​of the period. The autocorrelation function or periodogram can be used to assist in the estimation of the frequency. Analyze the phase change of the signal. The phase information can be obtained by calculating the phase difference of continuous waveforms, or extracted through the complex representation after Fourier transform.

[0101] The detection steps proposed in this embodiment can detect the vibration state of the wind turbine transmission chain in real time and accurately identify abnormal vibration modes, thereby providing early warning of possible faults, effectively extending the service life of the wind turbine and improving its operating efficiency and safety.

[0102] To sum up, with the help of the above-mentioned technical scheme of the present invention, the present invention adopts a specially designed whispering gallery mode microcavity structure and optical frequency comb technology to achieve high-sensitivity detection of tiny vibration signals. Compared with the traditional vibration detection method based on acceleration sensor, it can provide high-resolution vibration signal detection in a wider frequency range, and has significant resistance to environmental interference. At the same time, it can provide more sophisticated frequency response analysis, which makes it have obvious advantages in detection accuracy and stability, thereby not only improving the accuracy of fault detection, but also reducing the cost caused by frequent maintenance or unplanned downtime, and significantly enhancing the reliability and economic benefits of wind turbines.

[0103] The present invention realizes high-precision capture of extremely small physical changes in the wind turbine transmission chain through the whispering gallery mode microcavity sensor, which changes the problem that the traditional acceleration sensor is limited by its physical size and sensitivity and cannot detect small or high-frequency vibration signals, and can identify small vibration changes, thereby providing the possibility for early fault warning, greatly reducing the sudden shutdown and maintenance costs caused by faults, and improving the reliability and operation efficiency of the wind turbine generator set. The wind turbine transmission chain vibration detection method based on the whispering gallery mode microsphere cavity provided by the present invention can detect and analyze the vibration of the wind turbine transmission chain with high precision and high sensitivity, and has the characteristics of anti-interference ability and adaptability to harsh environments. Based on the use of optical whispering gallery mode microcavity sensing technology, it can realize the accurate capture of small vibrations in the wind turbine transmission chain, thereby monitoring the health status of the equipment in real time, and can warn of possible faults and damages at an early stage, so as to improve the reliability and economic benefits of wind power generation.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wind turbine transmission chain vibration detection method based on whispering gallery mode microcavity, characterized in that: The wind turbine transmission chain vibration detection method comprises: Based on the optical fiber coupling technology, the laser light source is introduced into the whispering gallery mode microcavity, and the whispering gallery mode microcavity is used to obtain the vibration response signal at the transmission chain position of the wind turbine. The vibration response signal is converted into a digital signal using signal processing technology, and the digital signal is analyzed and processed in combination with a digital signal processor, and the vibration information at the position of the wind turbine transmission chain is obtained based on the processing result.

2. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 1, characterized in that: The method of introducing a laser light source into a whispering gallery mode microcavity based on an optical fiber coupling technology and obtaining a vibration response signal at a position of a wind turbine transmission chain by using the whispering gallery mode microcavity comprises: Install a whispering gallery mode microcavity at a set position of the wind turbine transmission chain, adjust the laser power using a laser controller, and then turn on the laser to emit a laser light source to the wind turbine transmission chain; The laser light source is received by using an optical fiber coupler, and after adjusting the relative position between the optical fiber coupler and the whispering gallery mode microcavity, the laser light source is introduced into the whispering gallery mode microcavity; The state information of the laser light source in the whispering gallery mode microcavity is analyzed, and the vibration response signal at the position of the wind turbine transmission chain is obtained based on the state information.

3. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 2 is characterized in that: The laser is a continuous wave laser with an output power of 15 mW, and the laser light source is a supercontinuum light source.

4. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 2, characterized in that: The analyzing the state information of the laser light source in the whispering gallery mode microcavity and acquiring the vibration response signal at the position of the wind turbine transmission chain based on the state information comprises: The whispering gallery mode microcavity receives the laser light source. Based on the spherical structure of the whispering gallery mode microcavity, the laser light source propagates in the whispering gallery mode microcavity according to the set mode. Analyze the state information of the laser light source in the whispering gallery mode microcavity sensor cavity according to the propagation results, and determine the reflection information of the laser light source based on the state information to obtain a closed optical path; The mass change of the whispering gallery mode microcavity is analyzed based on the closed optical path, and the resonant frequency change of the laser light source is calculated using the mass change and the preset resonant frequency. The vibration at the position of the wind turbine transmission chain is induced according to the change of the resonant frequency, and the vibration response signal of the whispering gallery mode microcavity is obtained by using the vibration sensing result.

5. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 4, characterized in that: The expression of the resonant frequency change is: Where Δf represents the change in resonance frequency, f0 represents the resonance frequency of the whispering gallery mode microcavity when it is not affected by vibration, Δm represents the change in the effective mass of the whispering gallery mode microcavity due to vibration, and m0 represents the effective mass of the whispering gallery mode microcavity when it is not affected by vibration.

6. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 1, characterized in that: The method of converting the vibration response signal into a digital signal by using a signal processing technology, analyzing and processing the digital signal in combination with a digital signal processor, and obtaining the vibration information at the position of the wind turbine transmission chain based on the processing result includes: The vibration response signal is transmitted through an optical fiber coupler, and the vibration response signal is received by a photodetector, and the vibration response signal is converted into an electrical signal based on a photodiode; After the electric signal is amplified by the signal amplifier, the electric signal is converted into a digital signal by using the signal conversion circuit; Use a digital signal processor to perform Fourier transform on the digital signal, obtain the spectrum of the digital signal based on the transform result, and design a bandpass filter to combine with the spectrum to generate a filtered signal; The nonlinear trend removal technology is used to preprocess the filtered signal, and the signal change amplitude and phase change are analyzed according to the processing results. The vibration information at the position of the wind turbine transmission chain is obtained based on the signal change amplitude and phase change.

7. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 6, characterized in that: The method of performing Fourier transform on the digital signal using a digital signal processor, obtaining the spectrum of the digital signal based on the transform result, and designing a bandpass filter to combine with the spectrum to generate a filtered signal includes: Performing Fourier transform operation on the digital signal using a digital signal processor, and converting the digital signal into a frequency domain based on the transform result to obtain a spectrum of the digital signal; Based on the preset lower cutoff frequency and upper cutoff frequency, the frequency range allowed to pass by the bandpass filter is defined, and the frequency range is combined with the frequency variable to design the bandpass filter; The digital signal is filtered using a bandpass filter and the spectrum of the digital signal, and an inverse Fourier transform is performed on the digital signal based on the filtering result to obtain a filtered signal in the regression time domain.

8. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 7, characterized in that: The expression of the frequency spectrum of the digital signal is: In the formula, S(f) represents the spectrum of the digital signal, s(t) represents the digital signal, t represents the time variable, f represents the frequency variable, e represents the conversion factor, j represents the imaginary unit, and d represents the summation of the digital signal in the time variable.

9. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 8, characterized in that: The expression of the filtered signal is: Where s`(t) represents the filtered signal after inverse Fourier transform regression to the time domain, s(t) represents the digital signal, t represents the time variable, f represents the frequency variable, e represents the conversion factor, j represents the imaginary unit, and d represents the summation of the digital signal in the time variable.

10. The method for detecting vibration of a wind turbine transmission chain based on a whispering gallery mode microcavity according to claim 9, characterized in that: The method of preprocessing the filtered signal using the nonlinear trend removal technology, analyzing the signal change amplitude and phase change according to the processing result, and obtaining the vibration information at the position of the wind turbine transmission chain based on the signal change amplitude and phase change includes: Generate a trend curve of the filtered signal based on a nonlinear trend removal technique, and remove the trend curve from the filtered signal to obtain a detrended filtered signal; The difference between the maximum value and the minimum value of the filtered signal is obtained to obtain the peak-to-valley amplitude, and the vibration amplitude at the position of the wind turbine transmission chain is determined based on the peak-to-valley amplitude; Using the periodic characteristics of the filtered signal, the maximum and minimum periodic values ​​of the filtered signal are estimated, and the vibration frequency at the position of the wind turbine transmission chain is determined based on the periodic difference result; A continuous waveform of the filtered signal is obtained, the phase difference of the filtered signal is analyzed according to the phase difference of the continuous waveform, and the vibration phase at the position of the transmission chain of the wind turbine generator is obtained based on the phase difference.

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