Fan blade variable pitch control method and device based on fiber bragg grating

Abstract

The invention provides a fan blade variable pitch control method based on a fiber bragg grating, which is applied to control equipment and comprises the following steps: receiving a strain value provided by the fiber bragg grating which is mounted on a fan blade and used for measuring the strain value of the fan blade; and controlling the rotation of the fan blade according to the received strain value so as to adjust the windward side of the fan blade. According to the technical scheme, the strain of the fan blade can be detected in real time through the fiber bragg grating, the windward area of the blade is adjusted according to the strain value, and the working efficiency of the fan is effectively improved on the basis that the safety of the fan is guaranteed.

Description

Technical Field

[0001] This application relates to the technical field of wind turbine pitch control, and particularly to a method, device, computer equipment, and computer-readable storage medium for pitch control of wind turbine blades based on fiber Bragg gratings. Background Art

[0002] Wind turbines are important devices for converting wind energy into electrical energy. During the operation of a wind turbine, changes in the wind and complex working environments will exert different degrees of force on the blades, causing stress and strain on the blades, and ultimately leading to fatigue damage and efficiency decline of the blades.

[0003] However, giving early warnings before the blades are irreparably damaged only considers the safety protection of the wind turbine and cannot improve the working efficiency of the wind turbine, resulting in poor performance of the wind turbine system.

[0004] It should be noted that the above content is not necessarily prior art and is not used to limit the patent protection scope of this application. Summary of the Invention

[0005] This application provides a method, device, computer equipment, and computer-readable storage medium for pitch control of wind turbine blades based on fiber Bragg gratings to solve or alleviate one or more of the above technical problems.

[0006] One aspect of this application provides a method for pitch control of wind turbine blades based on fiber Bragg gratings, which is applied to a control device. The method includes:

[0007] Receiving the strain value provided by the fiber Bragg grating, where the fiber Bragg grating is installed on the wind turbine blade and is used to measure the strain value of the wind turbine blade; and

[0008] Controlling the rotation of the wind turbine blade according to the received strain value to adjust the windward side of the wind turbine blade.

[0009] Optionally, the number of the fiber Bragg gratings is determined according to a preset rule, and one or more of the fiber Bragg gratings are installed on the inner side of the blade root of the wind turbine blade in a preset manner;

[0010] Wherein, one or more of the fiber Bragg gratings are used to measure the axial strain value and / or the radial strain value of the wind turbine blade.

[0011] Optionally, the strain value of the wind turbine blade is measured by the following operations:

[0012] Obtaining the initial wavelength, elasto-optic coefficient, and wavelength change amount of the fiber Bragg grating;

[0013] Determining the strain value of the wind turbine blade according to the initial wavelength, the elasto-optic coefficient, and the wavelength change amount.

[0014] Optionally, controlling the rotation of the fan blade according to the received strain value includes:

[0015] When the strain value is less than or equal to a preset strain threshold, rotating the fan blade in a first clockwise direction;

[0016] Monitoring the real-time strain value of the rotated fan blade: when the real-time strain value increases and is less than or equal to the preset strain threshold, continuing to rotate the fan blade in the first clockwise direction; when the real-time strain value decreases or is greater than the preset strain threshold, rotating the fan blade in a second clockwise direction.

[0017] Optionally, controlling the rotation of the fan blade according to the received strain value further includes:

[0018] Monitoring the real-time strain value of the fan blade rotated in the second clockwise direction;

[0019] When the real-time strain value increases and is less than the preset strain threshold, continuing to rotate the fan blade in the second clockwise direction.

[0020] Optionally, controlling the rotation of the fan blade includes:

[0021] Adjusting the pitch angle and / or blade shape of the fan blade to adjust the windward side of the fan blade.

[0022] Optionally, the method further includes:

[0023] Receiving the real-time rotation speed of the fan blade measured by the fiber Bragg grating and a preset sensor;

[0024] Determining the error between the real-time rotation speed and the preset target rotation speed through a PID control algorithm to adjust the rotation speed of the fan blade.

[0025] Another aspect of the present application provides a pitch control device for a fan blade based on a fiber Bragg grating, which is applied to a control device. The device includes:

[0026] A receiving module for receiving the strain value provided by the fiber Bragg grating, where the fiber Bragg grating is installed on the fan blade and used to measure the strain value of the fan blade; and

[0027] A control module for controlling the rotation of the fan blade according to the received strain value to adjust the windward side of the fan blade.

[0028] Another aspect of the present application provides a computer device, including:

[0029] At least one processor; and

[0030] A memory communicatively connected to the at least one processor;

[0031] Wherein: the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the method as described above.

[0032] Another aspect of the embodiments of the present application provides a computer-readable storage medium, in which computer instructions are stored, and when the computer instructions are executed by a processor, the method as described above is implemented.

[0033] Another aspect of the present application further provides a pitch control system for a wind turbine blade based on a fiber Bragg grating. The system includes:

[0034] A fiber Bragg grating, installed on the wind turbine blade and used to measure the strain value of the wind turbine blade;

[0035] A control device, coupled to the fiber Bragg grating;

[0036] Wherein, the control device is configured to: receive the strain value of the wind turbine blade measured by the fiber Bragg grating; and control the rotation of the wind turbine blade according to the received strain value to adjust the windward surface of the wind turbine blade.

[0037] The embodiments of the present application adopting the above technical solutions may include the following advantages:

[0038] The fiber Bragg grating is pre-installed on the wind turbine blade and used to measure the strain value of the wind turbine blade, so that the control device can control the pitch of the wind turbine blade based on the fiber Bragg grating. Specifically: the control device receives the strain value of the wind turbine blade provided by the fiber Bragg grating; according to the received strain value, it controls the rotation of the wind turbine blade (pitch angle, blade shape, etc.) to realize the adjustment of the windward area of the blade. It can be seen that the embodiments of the present application can realize the real-time detection of the strain of the wind turbine blade through the fiber Bragg grating, and adjust the windward area of the blade according to the strain value, effectively improving the working efficiency of the wind turbine while ensuring the safety of the wind turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings exemplarily show embodiments and form a part of the specification, and are used together with the written description of the specification to explain the exemplary embodiments. The shown embodiments are for illustrative purposes only and do not limit the scope of the claims. In all the drawings, the same reference numerals refer to similar but not necessarily identical elements.

[0040] Figure 1 Schematically shows a block diagram of a pitch control system for a wind turbine blade based on a fiber Bragg grating according to Embodiment 1 of the present application;

[0041] Figure 2 Schematically shows a flowchart of a pitch control method for a wind turbine blade based on a fiber Bragg grating according to Embodiment 2 of the present application;

[0042] Figure 3 Schematically shows Figure 2 a sub-step flowchart of step S202 in

[0043] Figure 4 Schematically shows Figure 2 a sub-step flowchart of step S202 in

[0044] Figure 5 is an application example diagram of a pitch control method for a wind turbine blade based on a fiber Bragg grating according to Embodiment 2 of the present application;

[0045] Figure 6 is an application example diagram of a pitch control method for a wind turbine blade based on a fiber Bragg grating according to Embodiment 2 of the present application;

[0046] Figure 7 is an application example diagram of a pitch control method for a wind turbine blade based on a fiber Bragg grating according to Embodiment 2 of the present application;

[0047] Figure 8 Schematically shows a block diagram of a pitch control device for a wind turbine blade based on a fiber Bragg grating according to Embodiment 3 of the present application; and

[0048] Figure 9 Schematically shows a schematic diagram of the hardware architecture of a computer device according to Embodiment 4 of the present application. Detailed implementation manners

[0049] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0050] It should be noted that the descriptions involving "first", "second", etc. in the embodiments of the present application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions appears to be contradictory or unable to be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0051] In the description of the present application, it should be understood that the numerical labels before the steps do not identify the order of execution of the steps, but are only used to facilitate the description of the present application and distinguish each step. Therefore, it should not be construed as a limitation of the present application.

[0052] First, the following are the term explanations involved in the present application:

[0053] Stress: The distribution of force per unit area acting on the interior or surface of an object. Its magnitude and direction depend on the magnitude of the applied force, the magnitude and direction of the acting area, as well as the geometric shape and material properties of the object. Stress is used to describe the degree of influence of external forces on an object.

[0054] Strain: The change in shape or size of an object under the action of an external force. Strain is used to describe the degree of deformation of an object.

[0055] Fiber Bragg grating: An optical device that manipulates and processes optical signals by introducing periodic refractive index changes in an optical fiber.

[0056] Secondly, to facilitate the understanding of the technical solutions provided in the embodiments of the present application by those skilled in the art, the related technologies are described below:

[0057] Wind energy is a renewable clean energy source, and wind turbines are important devices for converting wind energy into electrical energy. During the operation of a wind turbine, changes in the wind and complex working environments exert different degrees of force on the blades, causing stress and strain in the blades, ultimately leading to fatigue damage and reduced efficiency of the blades.

[0058] However, the applicant has learned that: The related technologies only consider the safety protection of the wind turbine by giving early warnings before the blades are irreparably damaged, but cannot improve the working efficiency of the wind turbine, resulting in poor performance of the wind turbine system.

[0059] For this reason, the embodiments of the present application provide a technical solution for pitch control of wind turbine blades based on fiber Bragg gratings. In this technical solution: (1) Real-time detection of the strain (stress) of the wind turbine blades is achieved through fiber Bragg grating strain (stress) sensors connected to the fiber Bragg gratings, and the rotation of the blades (pitch angle / blade shape) is controlled according to the strain (stress) to adjust the size of the windward area of the blades, thereby improving the safety and working efficiency of the wind turbine system; (2) The PID (Proportional (P)–Integral (I)–Derivative (D)) control algorithm is used to precisely adjust the rotational speed of the wind turbine to optimize the operating efficiency of the wind turbine system. See the following for details.

[0060] The technical solutions of the present application will be introduced through multiple embodiments. It should be noted that these embodiments can be implemented in many different forms and should not be construed as being limited only to the embodiments described herein.

[0061] Embodiment 1

[0062] Figure 1 A block diagram of a pitch control system for a wind turbine blade based on fiber Bragg grating according to Embodiment 1 of the present application is schematically shown.

[0063] As Figure 1 shown, the pitch control system for a wind turbine blade based on fiber Bragg grating may include a fiber Bragg grating, a control device, and a wind turbine blade.

[0064] Next, the functions and cooperation relationships of each component will be introduced in conjunction with Figure 1 the following.

[0065] The fiber Bragg grating can be installed on the wind turbine blade according to a preset rule and is used to measure the strain value or stress value of the wind turbine blade. The number and installation position of the fiber Bragg grating can be determined according to actual control accuracy, control efficiency, etc. requirements. For example, 4 fiber Bragg gratings can be fixed on the inner side of the blade root of the same blade at intervals of 90° and kept at the same distance from the bottom of the blade root, which can more accurately measure the strain (or stress) conditions in the axial and radial directions of the blade root and collect strain (or stress) signals.

[0066] In practical applications, the fiber Bragg grating may include a fiber Bragg grating structure and a fiber Bragg grating strain sensor. Connecting the fiber Bragg grating structure and the fiber Bragg grating strain sensor facilitates the use of the characteristics of the grating structure to monitor and measure the strain (or stress) conditions of the blade in real time.

[0067] The control device can be coupled with the fiber Bragg grating and the wind turbine blade. The control device can be used to receive the strain (or stress) value of the wind turbine blade measured by the fiber Bragg grating and judge the force on the blade according to the received strain (or stress) value and control the rotation of the wind turbine blade. For example: by adjusting the pitch angle or blade shape, etc., the adjustment of the windward area size of the wind turbine blade can be realized.

[0068] In some embodiments, the control device can also achieve real-time control of the wind turbine speed through the PID control algorithm to ensure that the wind turbine speed can be accurately adjusted according to the real-time monitored data to further improve the working efficiency of the wind turbine.

[0069] In this embodiment, through the cooperation of the fiber Bragg grating and the control device, the working efficiency of the wind turbine can be maximized while ensuring the safety of the wind turbine, and the wind turbine system can be optimized.

[0070] Embodiment 2

[0071] The pitch control method of the wind turbine blade based on fiber Bragg grating in this embodiment is applied to a control device.

[0072] Figure 2 Schematically shows a flowchart of the pitch control method of the wind turbine blade based on fiber Bragg grating according to Embodiment 2 of the present application.

[0073] As Figure 2 shown, the pitch control method of the wind turbine blade based on fiber Bragg grating may include steps S200 to S202, where:

[0074] Step S200, receiving the strain value provided by the fiber Bragg grating, where the fiber Bragg grating is installed on the wind turbine blade and is used to measure the strain value of the wind turbine blade.

[0075] Step S202, controlling the rotation of the wind turbine blade according to the received strain value to adjust the windward surface of the wind turbine blade.

[0076] For the pitch control method of the wind turbine blade based on fiber Bragg grating provided in this embodiment, the fiber Bragg grating is pre-installed on the wind turbine blade and is used to measure the strain value of the wind turbine blade, so that the control device can control the pitch of the wind turbine blade based on the fiber Bragg grating. Specifically: the control device receives the strain value of the wind turbine blade provided by the fiber Bragg grating; according to the received strain value, controls the rotation of the wind turbine blade (pitch angle, blade shape, etc.) to realize the adjustment of the size of the windward area of the blade. It can be seen that the embodiment of the present application can realize the real-time detection of the strain of the wind turbine blade through the fiber Bragg grating, and adjust the windward area of the blade according to the strain value, effectively improving the working efficiency of the wind turbine on the basis of ensuring the safety of the wind turbine.

[0077] The following will Figure 2 , elaborate in detail on each step in steps S200 to S202 and other optional steps.

[0078] Step S200 , receiving the strain value provided by the fiber Bragg grating, where the fiber Bragg grating is installed on the wind turbine blade and is used to measure the strain value of the wind turbine blade.

[0079] The fiber Bragg grating may include a Fiber Bragg Grating (FBG), a Long Period Grating (LPG), a Fiber Grating Array, etc. As an optical filtering device, the central wavelength of the reflected light of the fiber Bragg grating is sensitive to temperature, strain, and stress. Therefore, based on this physical property of the fiber Bragg grating, the changes of related physical quantities can be monitored.

[0080] Since the refractive index of the fiber core in the fiber grating changes periodically along the axial direction, it generates coherent reflection with the frequency that matches the phase in the incident light, presenting in the form of optical filtering. A small part of the broadband light propagating through the fiber grating will be reflected under specific conditions, and this special optical property enables it to be used as a narrowband filter. Among them, the relationship between the reflected light and the transmitted light passing through the grating can satisfy the following formula:

[0081] β1 - β2 = 2Λπ

[0082] Among them, Λ represents the grating period of the fiber grating, and β1 and β2 represent the phases of two transmission modes respectively. When light passes through the fiber grating, mode coupling occurs between the core modes of forward transmission and backward transmission, causing the core mode of forward transmission to change into the core mode of backward transmission. At this time, the phase can satisfy the following formula:

[0083] 2π = β1 - β2 = β 01 -(-β 01 ) = 2β 01 Λ

[0084] In this case, the obtained grating period is relatively small (Λ < 1μm), such as the fiber Bragg grating. The following will take the fiber Bragg grating as an example to introduce the process of measuring the strain value of the fiber grating.

[0085] When a beam of broadband light passes through the fiber Bragg grating, the part whose wavelength value matches the fiber Bragg grating will be reflected, and the change in the reflected wavelength can directly reflect the change in the monitored external physical quantity. The Bragg wavelength λ B can be expressed by the following formula:

[0086] λ B = 2n eff Λ

[0087] Among them, n eff represents the effective refractive index of the fiber core of the fiber grating.

[0088] When the fiber grating undergoes strain under the influence of the outside world, its core refractive index period Λ will change. At the same time, affected by the elasto-optic effect, the effective refractive index n of the fiber core efIt will also change, resulting in a change in the central wavelength of the reflected light of the fiber grating, that is, changing from the initial wavelength (or the zeroed wavelength after installation) to the current wavelength. Among them, both the initial wavelength and the current wavelength can be demodulated by the demodulator in the fiber grating strain sensor. During the process of measuring strain, since the fiber grating is sensitive to temperature, the influence of temperature on the central wavelength of the fiber grating is much greater than that of strain. Therefore, when the temperature changes greatly, it is necessary to pre-eliminate the influence of temperature when using the fiber grating to measure strain, so as to reduce the influence on the measurement accuracy of strain. Without considering the coupling effect of temperature and strain, assuming that the changes in the central wavelength caused by temperature and strain are linear and independent of each other, the wavelength change jointly produced by temperature and strain can be expressed as follows:

[0089] The strain value m = Δε = [(λ - λ0) - (λ Τ - λ Τ0 ) * Β] * K (με)

[0090] Among them, λ0 is the initial wavelength of the fiber grating, unit: nm; λ is the current wavelength (actual central wavelength) of the fiber grating, unit: nm; λ Τ0 is the initial wavelength of the temperature-compensated fiber grating, unit: nm; λ Τ is the measured wavelength of the temperature-compensated grating, unit: nm; B is the temperature compensation coefficient; K is the strain coefficient, unit: με / nm.

[0091] If the influence of temperature factors on the central wavelength of the reflected light of the fiber grating is excluded, and only considering the influence factor of strain, the central wavelength of the reflected light can be expressed by the following formula:

[0092]

[0093] Among them, λ B represents the wavelength change under the influence of single strain, and the refractive index change caused by the elasto-optic effect is expressed as n eff , The elongation produced under the influence of stress is expressed as ΔL.

[0094] Then the wavelength change can be determined by the following formula:

[0095]

[0096] Among them, Δλ B represents the change in the wavelength of the fiber grating, λ B represents the original wavelength without external influence, P e represents the elasto-optic coefficient, ε zz represents the axial strain.

[0097] It can be known that the fiber Bragg grating can measure strain by the change of the center wavelength of the reflected light. Therefore, the fiber Bragg grating can be installed on the fan blade to measure the strain value of the fan blade. An exemplary strain value acquisition scheme is provided below.

[0098] In an alternative embodiment, the strain value of the fan blade is measured by the following operations: obtaining the initial wavelength, the photoelastic coefficient, and the wavelength change amount of the fiber Bragg grating; determining the strain value of the fan blade according to the initial wavelength, the photoelastic coefficient, and the wavelength change amount.

[0099] As described above, obtain the wavelength change amount Δλ of the reflected light of the fiber Bragg grating installed on the fan blade B , combined with the photoelastic coefficient P e and the initial wavelength (original wavelength) λ of the fiber Bragg grating without external influence B , the strain value of the fan blade can be quickly calculated.

[0100] In this embodiment, through the change of the center wavelength of the reflected light, the strain value of the fan blade can be measured efficiently and accurately.

[0101] There are various installation methods for the fiber Bragg grating, and an exemplary scheme will be provided below.

[0102] In an alternative embodiment, the number of the fiber Bragg gratings is determined according to a preset rule, and one or more of the fiber Bragg gratings are installed on the inner side of the root of the fan blade in a preset manner; wherein, one or more of the fiber Bragg gratings are used to measure the axial strain value and / or the radial strain value of the fan blade.

[0103] Exemplarily, in order to ensure the measurement accuracy and measurement efficiency, four fiber Bragg gratings can be configured for one fan blade. The four fiber Bragg gratings are surface-mounted on the inner side of the root of the same fan blade at intervals of 90°, and are kept at the same distance from the bottom of the root. Through this installation method, the strain conditions of the root axis and the radial direction can be accurately measured, and the corresponding strain signals can be collected.

[0104] In this embodiment, determining the installation position and the number of the fiber Bragg gratings according to actual requirements can ensure the measurement accuracy and efficiency, and further improve the control accuracy and efficiency.

[0105] In practical applications, the fiber Bragg grating can include a fiber Bragg grating structure and a fiber Bragg grating strain sensor. Connect the fiber Bragg grating strain sensor and the fiber Bragg grating structure, and monitor the change of the center wavelength of the reflected light of the fiber Bragg grating structure through the demodulator in the fiber Bragg grating strain sensor, so as to monitor and measure the strain condition of the fan blade in real time, and send the measured strain value to the control device.

[0106] In this embodiment, the fiber Bragg grating strain sensor connected to the fiber Bragg grating structure can be used to realize the real-time detection of the strain of the fan blade. The control device can quickly judge the force condition of the fan blade by receiving the strain value provided by the fiber Bragg grating, so as to perform blade pitch control subsequently.

[0107] Step S202 , according to the received strain value, control the rotation of the fan blade to adjust the windward surface of the fan blade.

[0108] The control device makes a logical judgment according to the received strain value, and can determine the current state of the fan blade. When the fan blade is in a safe state, the working state of the fan blade is adjusted by controlling the rotation of the fan blade (such as adjusting the pitch angle or blade shape) to maximize the working efficiency. During the process of adjusting the fan blade, the real-time strain value of the fan blade can also be monitored by the fiber Bragg grating to avoid irreparable damage to the blade and further ensure the safety of the fan system. There are various methods to control the rotation of the fan blade, and multiple exemplary solutions will be provided below.

[0109] In an alternative embodiment, as Figure 3 shown, step S202 may include:

[0110] Step S300, when the strain value is less than or equal to the preset strain threshold, rotate the fan blade along the first clockwise direction.

[0111] Step S302, monitor the real-time strain value of the rotated fan blade.

[0112] Step S304, when the real-time strain value increases and is less than or equal to the preset strain threshold, continue to rotate the fan blade along the first clockwise direction.

[0113] Step S306, when the real-time strain value decreases or is greater than the preset strain threshold, rotate the fan blade along the second clockwise direction.

[0114] Exemplarily, the preset strain threshold of the fan blade can be pre-configured according to preset rules, such as setting based on the material properties of the fan blade, setting through experiments and simulations, etc. When the strain value received by the control device is less than the preset strain threshold, the control device controls the fan blade to rotate along the first clockwise direction (clockwise) to finely adjust the windward surface of the fan blade clockwise. During the process of finely adjusting the windward surface of the fan blade clockwise, the real-time strain value of the fan blade is monitored. When the real-time strain value of the fan blade continuously increases and is less than or equal to the preset strain threshold, the windward surface of the fan blade can be continuously finely adjusted clockwise to improve the working efficiency of the fan, otherwise, the windward surface of the fan blade will be finely adjusted along the second clockwise direction (counterclockwise) to avoid adjustment errors.

[0115] In this embodiment, by monitoring the change of the real-time strain value during the fine-tuning process, the steering of the fan blade can be adjusted correctly and in a timely manner, so as to more accurately control the windward side of the blade and improve the working efficiency of the fan.

[0116] In an alternative embodiment, as Figure 4 shown, step S202 may further include:

[0117] Step S400, monitoring the real-time strain value of the fan blade after rotating along the second clockwise direction.

[0118] Step S402, when the real-time strain value increases and is less than the preset strain threshold, continue to rotate the fan blade along the second clockwise direction.

[0119] When counterclockwise fine-tuning the windward side of the fan blade, if the real-time strain value is continuously increasing and less than or equal to the preset strain threshold, the windward side of the fan blade can be continuously fine-tuned counterclockwise to improve the working efficiency of the fan, otherwise this round of adjustment of the fan blade will end.

[0120] In this embodiment, by monitoring the change of the real-time strain value during the counterclockwise fine-tuning process, continuing to fine-tune the windward side counterclockwise or terminating this round of adjustment can ensure the safety of the fan and optimize the fan performance as a whole.

[0121] The above-mentioned multiple embodiments introduce improving the working efficiency of the fan by adjusting the windward side of the fan blade. Next, how to further optimize the working efficiency of the fan will be introduced.

[0122] In an alternative embodiment, the fiber grating-based pitch control method for fan blades may further include: receiving the real-time rotation speed of the fan blade measured by the fiber grating and a preset sensor; determining the error between the real-time rotation speed and the preset target rotation speed through a PID control algorithm to adjust the rotation speed of the fan blade.

[0123] The PID control algorithm consists of a proportional term (P term), an integral term (I term), and a derivative term (D term), and can be used for dynamic adjustment and control of the error of the system. Among them, the proportional term P is used to proportionally amplify the error, the integral term I is used to accumulate the error and eliminate the static error, and the derivative term D is used to predict the change trend of the error. Through reasonable parameter settings, the PID control algorithm can achieve fast and stable control of the fan rotation speed. Its calculation formula can be expressed as follows:

[0124]

[0125] In practical applications, appropriate PID parameters can be set according to actual needs, including the proportional coefficient K p , integral coefficient K I and derivative coefficient KD The settings of these parameters can be adjusted according to experience to achieve fast and stable system response.

[0126] Exemplarily, a fiber Bragg grating and other sensors (such as an acceleration sensor) can be combined to comprehensively determine the real-time rotational speed of the fan blade. Based on this, the error between the real-time rotational speed and the expected rotational speed of the fan blade can be calculated. Then, the proportional, integral, and differential parts of the error are calculated and weighted and summed with corresponding weight coefficients to obtain the final control quantity. By adjusting the rotational speed of the fan blade in real time according to the control quantity, the windward surface of the fan blade can be adjusted more accurately, optimizing the operating efficiency of the fan system.

[0127] To make the present application easier to understand, the following provides an exemplary application in combination with Figure 5 -7.

[0128] S11: Determine the position and quantity of the fiber Bragg grating and fix the fiber Bragg grating on the fan blade to ensure good contact and installation.

[0129] S12: Use the principle of the fiber Bragg grating strain sensor for strain monitoring, connect the fiber Bragg grating strain sensor and the fiber Bragg grating structure to monitor and measure the strain of the blade in real time.

[0130] S13: Use the strain value measured by the fiber Bragg grating strain sensor to judge the force on the blade. Adjust the windward area according to the force on the blade. The windward area of the blade is adjusted by adjusting the pitch angle or the shape of the blade, etc.

[0131] First, initialize the relevant parameters of the fan blade (strain upper limit Max, real-time strain value m, blade pitch, etc.), and analyze and judge the blade information transmitted by the strain sensor. Specifically:

[0132] If the real-time stress value m is less than or equal to the stress upper limit Max, the windward surface of the fan blade is slightly adjusted clockwise, otherwise this logical judgment ends; when entering the clockwise micro-adjustment of the windward surface of the fan blade, during the fine adjustment process, if the real-time stress value m is continuously increasing and less than or equal to the stress upper limit Max, continue to clockwise micro-adjust the windward surface of the fan blade, otherwise start to counterclockwise micro-adjust the windward surface of the fan blade; when continuing to clockwise micro-adjust the windward surface of the fan blade, if the real-time stress value m is continuously increasing and less than or equal to the stress upper limit Max, enter the node of continuing to clockwise micro-adjust the windward surface of the fan blade again, enter a loop, otherwise, this logical judgment ends; when counterclockwise micro-adjusting the windward surface of the fan blade, if the real-time stress value m is continuously increasing and less than or equal to the stress upper limit Max, enter the node of counterclockwise micro-adjusting the windward surface of the fan blade again, enter a loop, otherwise, this logical judgment ends.

[0133] S14: Adjust the fan speed using the PID control algorithm. Design a PID controller by combining the data obtained from the fiber Bragg grating and other sensors. Calculate the control signal to adjust the fan speed by measuring the deviation between the fan speed and the target speed.

[0134] In this exemplary application: (1) Realize the real-time detection of the strain (stress) of the fan blade through the fiber Bragg grating strain (stress) sensor connected to the fiber Bragg grating, and control the rotation of the blade (pitch angle / blade shape) according to the strain (stress) to adjust the windward area of the blade, thereby improving the safety and efficiency of the fan system; (2) Use the PID control algorithm to precisely adjust the fan speed to optimize the operating efficiency of the fan system.

[0135] Embodiment III

[0136] Figure 8 Schematically shows a block diagram of a fiber Bragg grating-based pitch control device for a fan blade according to Embodiment III of the present application. The device can be applied to a control device and can be divided into one or more program modules. One or more program modules are stored in a storage medium and are executed by one or more processors to complete the embodiments of the present application. The program modules referred to in the embodiments of the present application refer to a series of computer program instruction segments that can complete specific functions. The following description will specifically introduce the functions of each program module in this embodiment. As Figure 8 shown, the device 1000 may include: a receiving module 1100 and a control module 1200, where:

[0137] The receiving module 1100 is configured to receive the strain value provided by the fiber Bragg grating. The fiber Bragg grating is installed on the fan blade and is used to measure the strain value of the fan blade; and

[0138] The control module 1200 is configured to control the rotation of the fan blade according to the received strain value to adjust the windward surface of the fan blade.

[0139] As an optional embodiment, the number of the fiber Bragg gratings is determined according to a preset rule, and one or more of the fiber Bragg gratings are installed on the inner side of the blade root of the fan blade in a preset manner;

[0140] wherein, one or more of the fiber Bragg gratings are used to measure the axial strain value and / or the radial strain value of the fan blade.

[0141] As an optional embodiment, the strain value of the fan blade is measured through the following operations:

[0142] Obtain the initial wavelength, photoelastic coefficient, and the wavelength change amount of the fiber Bragg grating;

[0143] Determine the strain value of the fan blade according to the initial wavelength, the elasto-optic coefficient, and the wavelength change amount.

[0144] As an optional embodiment, the control module 1200 is further configured to:

[0145] When the strain value is less than or equal to a preset strain threshold, rotate the fan blade in the first clockwise direction;

[0146] Monitor the real-time strain value of the rotated fan blade: when the real-time strain value increases and is less than or equal to the preset strain threshold, continue to rotate the fan blade in the first clockwise direction; when the real-time strain value decreases or is greater than the preset strain threshold, rotate the fan blade in the second clockwise direction.

[0147] As an optional embodiment, the control module 1200 is further configured to:

[0148] Monitor the real-time strain value of the fan blade rotated in the second clockwise direction;

[0149] When the real-time strain value increases and is less than the preset strain threshold, continue to rotate the fan blade in the second clockwise direction.

[0150] As an optional embodiment, the control module 1200 is further configured to:

[0151] Adjust the pitch angle and / or the blade shape of the fan blade to adjust the windward side of the fan blade.

[0152] As an optional embodiment, the device 1000 is further configured to:

[0153] Receive the real-time rotation speed of the fan blade measured by the fiber Bragg grating and the preset sensor;

[0154] Determine the error between the real-time rotation speed and the preset target rotation speed through a PID control algorithm to adjust the rotation speed of the fan blade.

[0155] Embodiment IV

[0156] Figure 9 Schematically shows a hardware architecture diagram of a computer device 10000 suitable for implementing a pitch control method for a fan blade based on a fiber Bragg grating according to Embodiment IV of the present application. In some embodiments, the computer device 10000 may be a terminal device such as a smart phone, a wearable device, a tablet computer, a personal computer, a vehicle-mounted terminal, a game console, a virtual device, a workbench, a digital assistant, a set-top box, a robot, etc. In other embodiments, the computer device 10000 may be a rack-mounted server, a blade server, a tower server, or a cabinet server (including an independent server or a server cluster composed of multiple servers), etc. AsFigure 9 As shown, the computer device 10000 includes, but is not limited to: a memory 10010, a processor 10020, and a network interface 10030 that can communicate with each other through a system bus. Among them:

[0157] The memory 10010 includes at least one type of computer-readable storage medium. The readable storage medium includes flash memory, hard disk, multimedia card, card-type memory (such as SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disc, etc. In some embodiments, the memory 10010 can be an internal storage module of the computer device 10000, such as the hard disk or memory of the computer device 10000. In other embodiments, the memory 10010 can also be an external storage device of the computer device 10000, such as a plug-in hard disk, SmartMedia Card (SMC), Secure Digital (SD) card, FlashCard, etc. equipped on the computer device 10000. Of course, the memory 10010 can also include both the internal storage module and the external storage device of the computer device 10000. In this embodiment, the memory 10010 is generally used to store the operating system and various application software installed on the computer device 10000, such as the program code of the pitch control method for a wind turbine blade based on fiber Bragg grating. In addition, the memory 10010 can also be used to temporarily store various data that have been output or will be output.

[0158] In some embodiments, the processor 10020 can be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other chips. The processor 10020 is generally used to control the overall operation of the computer device 10000, such as performing control and processing related to data interaction or communication with the computer device 10000. In this embodiment, the processor 10020 is used to run the program code stored in the memory 10010 or process data.

[0159] The network interface 10030 may include a wireless network interface or a wired network interface, which is generally used to establish a communication link between the computer device 10000 and other computer devices. For example, the network interface 10030 is used to connect the computer device 10000 to an external terminal through a network, and establish a data transmission channel and a communication link between the computer device 10000 and the external terminal. The network can be a wireless or wired network such as an enterprise intranet (Intranet), the Internet, the Global System of Mobile communication (GSM for short), Wideband Code Division Multiple Access (WCDMA for short), 4G network, 5G network, Bluetooth, Wi-Fi, etc.

[0160] It should be noted that Figure 9 Only the computer device with components 10010 - 10030 is shown, but it should be understood that it is not required to implement all the shown components, and more or fewer components can be alternatively implemented.

[0161] In this embodiment, the fiber Bragg grating-based pitch control method for wind turbine blades stored in the memory 10010 can also be divided into one or more program modules and executed by one or more processors (such as the processor 10020) to complete the embodiments of this application.

[0162] Embodiment Five

[0163] The embodiments of this application also provide a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the fiber Bragg grating-based pitch control method for wind turbine blades in the embodiments are implemented.

[0164] In this embodiment, the computer-readable storage medium includes flash memory, hard disks, multimedia cards, card-type memories (such as SD or DX memories, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memories, magnetic disks, optical disks, etc. In some embodiments, the computer-readable storage medium may be an internal storage unit of a computer device, such as the hard disk or memory of the computer device. In other embodiments, the computer-readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc., equipped on the computer device. Of course, the computer-readable storage medium may also include both the internal storage unit and the external storage device of the computer device. In this embodiment, the computer-readable storage medium is generally used to store the operating system installed on the computer device and various application software, such as the program code of the pitch control method for a wind turbine blade based on fiber Bragg gratings in the embodiment. In addition, the computer-readable storage medium may also be used to temporarily store various data that have been output or are to be output.

[0165] Obviously, those skilled in the art should understand that the above-mentioned modules or steps of the embodiments of the present application can be implemented by a general-purpose computer device. They can be concentrated on a single computer device or distributed on a network composed of multiple computer devices. Optionally, they can be implemented by program codes executable by the computer device, so that they can be stored in a storage device and executed by the computer device. And in some cases, the steps shown or described can be executed in a sequence different from that here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to implement. Thus, the embodiments of the present application are not limited to any specific combination of hardware and software.

[0166] It should be noted that the above are only the preferred embodiments of the present application, and do not limit the patent protection scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present application.

Claims

1. A pitch control method for a wind turbine blade based on fiber Bragg grating, characterized in that, Applied to a control device, the method includes: Receiving a strain value provided by a fiber Bragg grating, the fiber Bragg grating being installed on a wind turbine blade and used to measure the strain value of the wind turbine blade; and Controlling the rotation of the wind turbine blade according to the received strain value to adjust the windward surface of the wind turbine blade.

2. The method according to claim 1, wherein The number of the fiber Bragg gratings is determined according to a preset rule, and one or more of the fiber Bragg gratings are installed inside the root of the wind turbine blade in a preset manner; Wherein, one or more of the fiber Bragg gratings are used to measure the axial strain value and / or the radial strain value of the wind turbine blade.

3. The method according to claim 1, wherein The strain value of the wind turbine blade is measured through the following operations: Obtaining the initial wavelength, the photoelastic coefficient and the wavelength change amount of the fiber Bragg grating; Determining the strain value of the wind turbine blade according to the initial wavelength, the photoelastic coefficient and the wavelength change amount.

4. The method according to any one of claims 1 to 3, characterized in that Controlling the rotation of the wind turbine blade according to the received strain value includes: When the strain value is less than or equal to a preset strain threshold, rotating the wind turbine blade along a first clockwise direction; Monitoring the real-time strain value of the rotated wind turbine blade: when the real-time strain value increases and is less than or equal to the preset strain threshold, continuing to rotate the wind turbine blade along the first clockwise direction; when the real-time strain value decreases or is greater than the preset strain threshold, rotating the wind turbine blade along a second clockwise direction.

5. The method according to claim 4, characterized in that Controlling the rotation of the wind turbine blade according to the received strain value further includes: Monitoring the real-time strain value of the wind turbine blade rotated along the second clockwise direction; When the real-time strain value increases and is less than the preset strain threshold, continuing to rotate the wind turbine blade along the second clockwise direction.

6. The method according to any one of claims 1 to 3, characterized in that Controlling the rotation of the wind turbine blade includes: Adjusting the pitch angle and / or the blade shape of the wind turbine blade to adjust the windward surface of the wind turbine blade.

7. The method according to any one of claims 1 to 3, characterized in that The method further includes: Receiving the real-time rotation speed of the wind turbine blade measured by the fiber Bragg grating and a preset sensor; Determining the error between the real-time rotation speed and a preset target rotation speed through a PID control algorithm to adjust the rotation speed of the wind turbine blade.

8. A pitch control device for a wind turbine blade based on fiber Bragg grating, characterized in that, Applied to a control device, the apparatus includes: A receiving module, configured to receive a strain value provided by a fiber Bragg grating, the fiber Bragg grating being installed on a wind turbine blade and used to measure the strain value of the wind turbine blade; and A control module, configured to control the rotation of the wind turbine blade according to the received strain value to adjust the windward surface of the wind turbine blade.

9. A computer device, characterized in that, Includes: At least one processor; And A memory communicatively connected to the at least one processor; wherein: The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Computer instructions are stored in the computer-readable storage medium, and when the computer instructions are executed by a processor, the method according to any one of claims 1 to 7 is implemented.

11. A pitch control system for a wind turbine blade based on fiber Bragg grating, characterized in that, The system includes: A fiber Bragg grating, installed on a wind turbine blade and used to measure the strain value of the wind turbine blade; A control device, coupling the fiber Bragg grating; Wherein, the control device is configured to: receive the strain value of the wind turbine blade measured by the fiber Bragg grating; and control the rotation of the wind turbine blade according to the received strain value to adjust the windward surface of the wind turbine blade.

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