Wind driven generator based on fiber bragg grating sensing detection and detection method

Abstract

The invention relates to a wind driven generator based on fiber bragg grating sensing detection and a detection method. The wind driven generator comprises a wind power blade embedded with a fiber bragg grating sensor and an optical fiber signal monitoring terminal. The wind power blade comprises a blade body and further comprises a composite material sensing unit poured into the blade body in the manufacturing process of the blade body. The composite material sensing unit comprises a composite material and a fiber bragg grating pre-embedded in the composite material, and the fiber bragg grating is connected with a fiber signal detection terminal. Compared with the prior art, the device can be pre-embedded in any part of the blade, does not need an additional bonding process, can cover the whole length range of the blade, realizes comprehensive defect detection of structural parts, non-structural parts and the like of the blade, and can realize on-line monitoring of the health state of the blade in the production process, the transportation process and the operation process of the blade.

Description

Technical Field

[0001] The invention relates to the field of wind turbines, and in particular to a wind turbine based on fiber grating sensing detection and a detection method. Background Art

[0002] At present, wind turbine blades on the market are mostly tested with load or vibration sensors in the field of health detection. This method requires the sensor to be adhered to the surface or inner cavity of the blade. It is difficult to detect defects along the entire length of the blade and cannot accurately capture small defects and defect locations. Although there are similar distributed fiber optic detection technologies in the world, the technology is not yet mature and the cost is high, which is not conducive to promotion.

[0003] For example, the invention with authorization announcement number CN208416812U discloses a health status self-monitoring wind turbine blade including a blade body of a wind turbine generator set, and a plurality of distributed optical fiber strain sensors are arranged on a molded structure in the length direction and / or chord direction of the blade body. The sensing length of each optical fiber strain sensor is 0.1 to 300 m, and the spatial resolution is 0.1 to 10000 mm. The tail end of each optical fiber strain sensor is provided with a connector that can be connected to a signal acquisition analyzer.

[0004] The invention with publication number WO2018206159A1 discloses a Wind turbine rotor blade with embedded sensors, wherein the rotor blade is characterized in that the structural element includes an optical fiber embedded in a pultruded fiber reinforced plastic material for monitoring the properties of the fiber reinforced plastic material and / or changes in the fiber reinforced material.

[0005] The invention with publication number EP3502467A1 discloses a Wind turbine rotor blade with embedded sensors stitched to drapable plies, wherein the rotor blade includes structural elements for supporting and / or reinforcing the rotor blade, such as spar caps, webs, root reinforcements, etc. The structural element is made of a pile of drapable continuous fiber mats or fabrics, called layers. The structural element sews a bare fiber Bragg grating on the fiber fabric to monitor the characteristics of the structural element.

[0006] In summary, existing sensors are adhered to the surface or inner cavity of the blade and are only deployed in local locations, making it difficult to detect defects along the entire length of the blade and unable to accurately capture small defects and defect locations. Summary of the invention

[0007] The purpose of the present invention is to provide a wind turbine and detection method based on fiber grating sensing detection in order to overcome the problems of the prior art, such as the existing sensors adhering to the surface or inner cavity of the blade, being only arranged at local positions and unable to detect defects along the entire length of the blade, and being unable to accurately capture small defects and defect locations.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] A wind turbine based on fiber grating sensing detection, comprising a wind turbine blade pre-embedded with a fiber grating sensor, and a fiber optic signal monitoring terminal;

[0010] The wind turbine blade comprises a blade body, and a composite material sensing unit poured into the blade body during the manufacturing process of the blade body; the composite material sensing unit comprises a composite material and a fiber Bragg grating pre-buried in the composite material, and the composite material sensing unit is a structural component integrally formed with the blade body, or a non-structural component pre-buried in the blade body; the shape and size of the composite material match the corresponding area of ​​the blade body, and the fiber Bragg grating is connected to the optical fiber signal monitoring terminal;

[0011] The optical fiber signal monitoring terminal includes a demodulation system and a computer terminal. The demodulation system is connected to the optical fiber Bragg grating and is used to demodulate the optical signal transmitted by the optical fiber Bragg grating and transmit it to the computer terminal. The computer terminal is used to process and analyze the signal transmitted by the demodulation system, so as to perform structural health detection of the blade.

[0012] Furthermore, the blade body is divided into a leading edge part and a trailing edge part, and the surface of the blade body is divided into a pressure side and a suction side; the outside of the blade body is wrapped by a blade shell with a continuous smooth curved surface, and the inside is a cavity structure supported by a main beam and a web.

[0013] Furthermore, the blade body is a fiber-reinforced composite material structure.

[0014] Furthermore, the fiber grating in the composite material sensing unit is provided with a plurality of grating measuring points connected in series; the number of the composite material sensing unit is one or more, and each composite material sensing unit is distributed in different parts of the blade body and connected in parallel with each other.

[0015] Furthermore, the distribution positions of the composite material sensing units include the main beam, the web, the leading edge, the trailing edge and / or the shell.

[0016] Furthermore, the demodulation system is used to convert the wavelength reflected by each fiber grating into a strain value and transmit it to a computer terminal; the computer terminal determines the health status of the wind turbine blade and the potential failure position of the composite material structure through a data post-processing module based on the signal transmitted by each fiber grating and its spatial position in the blade.

[0017] Furthermore, the composite material is a sheet or a profile.

[0018] When the composite material is a sheet, the fiber grating is located in the composite material and is co-solidified with the composite material;

[0019] When the composite material is a profile, the optical fiber Bragg grating is located inside the composite material.

[0020] Furthermore, the composite material comprises a reinforcing material and a matrix material, and the reinforcing material is glass fiber, carbon fiber, basalt fiber or organic fiber;

[0021] The matrix material is a synthetic resin, which is a thermosetting resin or a thermoplastic resin.

[0022] Furthermore, the optical fiber signal monitoring terminal is used to perform stress and strain monitoring, vibration monitoring and / or temperature monitoring based on the optical signal transmitted by the optical fiber Bragg grating.

[0023] The present invention also provides a defect damage detection method for a wind turbine generator based on fiber grating sensing detection as described above, comprising the following steps:

[0024] During the production process, transportation process, hoisting and / or operation of the blade, the optical signal transmitted by the composite material sensor unit injected into the blade body is collected through the optical fiber signal detection terminal, and the collected optical signal and its spatial position in the blade are recorded accordingly through the computer terminal. The health status of the wind turbine blade and the potential failure location of the composite material structure are determined through a dedicated data post-processing module and health judgment algorithm, thereby performing defect and damage detection for the blade throughout its life cycle from production to service.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) The present invention pre-embeds the fiber grating in a composite material with a certain rigidity to form a composite material sensing unit. The composite material sensing unit is poured into the blade during the blade manufacturing process and can be pre-embedded in any component of the blade without the need for an additional bonding process. The entire length of the blade can be covered, thereby achieving comprehensive defect detection of various structural components and non-structural components of the blade.

[0027] (2) The present invention can realize online monitoring of the health status of blades during the production process, transportation process and operation process of blades.

[0028] (3) The present invention uses a deep learning algorithm to perform anomaly detection on the data collected by the composite material sensor unit. When an abnormal signal value is collected, the computer terminal makes an abnormal judgment and gives corresponding early warning information, thereby realizing the full life cycle monitoring of the blades during the operation of the wind turbine. Compared with the manual analysis and judgment by existing technicians, the monitoring method involved in this patent has higher accuracy, reliability and weather resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a production process of a blade based on fiber grating sensing detection provided in an embodiment of the present invention;

[0030] In the figure, 1. blade body, 2. composite material, 3. fiber Bragg grating, 4. demodulation system, 5. wind turbine. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0034] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0035] Example 1

[0036] like Figure 1 As shown, this embodiment provides a wind turbine generator based on fiber grating sensing detection, including a wind turbine blade pre-embedded with a fiber grating sensor, and a fiber optic signal monitoring terminal;

[0037] The wind turbine blade comprises a blade body 1 and a composite material sensing unit (the numbers of the accompanying drawings include 2 and 3) poured into the blade body 1 during the manufacturing process of the blade body 1;

[0038] The composite material sensing unit includes a composite material 2 with a certain rigidity and a fiber grating 3 embedded in the composite material 2. The composite material sensing unit can be a structural component of the blade body 1 or a non-structural component. When the composite material sensing unit is used as a structural component, it can be embedded in structures including but not limited to the blade main beam, the shell sandwich structure, the blade web, etc., and be integrally formed with the blade to jointly participate in structural load-bearing.

[0039] The shape and size of the composite material 2 match the corresponding area of ​​the blade body 1, and the fiber grating 3 is connected to the fiber signal detection terminal. The composite material 2 is used to cover the outside of the fiber grating 3 to form a certain rigidity protection for the fiber grating 3.

[0040] The optical fiber signal monitoring terminal includes an optical demodulation system 4 and a computer terminal. The optical demodulation system 4 is connected to the fiber grating 3 and is used to demodulate the optical signal transmitted by the fiber grating 3 and transmit it to the computer terminal. The computer terminal is used to process and analyze the signal transmitted by the optical demodulation system 4, so as to monitor the structural health of the blade.

[0041] That is, the structure of the composite material 2 is not limited, and it will be connected with other structural and non-structural materials of the blade and embedded in the blade during the production process.

[0042] The number of composite material sensing units can be one or more; each composite material sensing unit is discretely distributed in one or more components of the main beam, web, leading edge, trailing edge and shell of the blade body 1. Preferably, the composite material sensing unit is arranged in each component of the blade body 1.

[0043] The new blade provided by the present invention comprises a composite material sensing unit, in which the optical fiber Bragg grating 3 is pre-embedded in a composite material 2 having a certain rigidity. The composite material sensing unit can be poured into the blade along with the blade manufacturing process, and can be pre-embedded in any component of the blade (structural and non-structural parts). The health status of the blade during the production process, transportation process and operation process can be monitored online, and defects can be warned in advance.

[0044] The blade body 1 is divided into a leading edge part and a trailing edge part, and the leading edge and the trailing edge divide the blade surface into a pressure side and a suction side. The outer shape of the blade is wrapped by a blade shell with a continuous smooth curved surface, and the interior of the blade is a cavity structure, and the shell is supported by a main beam and a web, and the fan blade is composed of a fiber-reinforced composite material structure.

[0045] The fiber Bragg grating 3 in the composite material sensing unit is a plurality of grating measuring points connected in series, and a plurality of composite material sensing units can be used in parallel at different parts of the blade body 1, including but not limited to the main beam, the web, the leading edge, the trailing edge and the shell, etc. The length of the fiber Bragg grating sensor can be adjusted by setting different grating measuring points, and the length of the optical fiber contained in the wind turbine blade can exceed the length of the blade itself by 20%, and can cover the entire blade to complete the full-length measurement, so the composite material sensing unit can measure the full strain field distribution of the entire blade in real time.

[0046] The composite material 2 is a sheet material or a profile material.

[0047] When the composite material 2 is a sheet material, it is preferably a homogeneous material of the blade, and the fiber grating 3 is located in the composite material layer and is co-solidified with the adjacent composite material.

[0048] When the composite material 2 is a profile, the fiber grating 3 is located inside the profile.

[0049] The composite material 2 comprises a reinforcing material, which is glass fiber, carbon fiber, basalt fiber or organic fiber (aramid fiber, ultra-high molecular weight fiber and natural fiber).

[0050] The composite material 2 includes a matrix material, which is a synthetic resin, including a thermosetting resin and a thermoplastic resin.

[0051] The optical fiber material of the optical fiber Bragg grating 3 is a common and femtosecond direct-writing Bragg grating, and the grating point interval can be within the range of 0 to 500, with an error of ±5 mm.

[0052] To further realize that the composite material sensing unit can be embedded in any component of the blade without any structural restrictions, this embodiment provides two structural forms of the composite material 2 as examples:

[0053] Structure 1: The composite material 2 is a plate-like planar structure, and the fiber grating 3 is connected between two adjacent layers of the composite material 2 and is fixed by the two layers of the composite material 2 , and is suitable for being poured into a relatively flat area in the blade body 1 .

[0054] Structure 2: The composite material 2 is a hollow cylindrical structure, and the fiber Bragg grating 3 is located in the middle through hole of the composite material 2. The diameter of the fiber Bragg grating 3 matches the diameter of the middle through hole of the composite material 2 to achieve reliable fixation. This structure requires a small area and is suitable for injection in a narrower area in the blade body 1.

[0055] The optical fiber signal detection terminal is used to perform stress and strain detection, vibration detection and / or temperature detection based on the optical signal transmitted by the optical fiber Bragg grating 3, thereby forming a stress and strain sensor, a vibration sensor and / or a temperature sensor as a whole with the composite material sensing unit.

[0056] The wavelength range of the light source at the input end of the optical fiber grating 3 in the composite material sensing unit is 10 to 10000 nm.

[0057] The optical fiber signal detection terminal includes a demodulation system 4 and a computer terminal. The demodulation system 4 is connected to the optical fiber Bragg grating 3 and is used to demodulate the optical signal transmitted by the optical fiber Bragg grating 3 and transmit it to the computer terminal. The computer terminal is used to perform structural health detection of the blade model transmitted by the demodulation system 4.

[0058] That is, by detecting the changes in the optical signals of the composite material sensing units corresponding to different positions of each blade component, the detection signals are returned to the demodulation system 4 via the fiber grating 3 and transmitted to the computer terminal. The data is analyzed and processed by the algorithm to realize the structural health detection of the blade during the blade production process, transportation process and operation process.

[0059] Specifically, the optical fiber signal monitoring terminal is used to perform stress and strain monitoring, vibration monitoring and / or temperature monitoring based on the optical signal transmitted by the optical fiber Bragg grating 3 .

[0060] Taking stress and strain monitoring as an example, the optical demodulation system can convert the wavelength reflected by each fiber grating sensor into a strain value and transmit it to a computer terminal. The computer terminal is used to record the signal transmitted by each grating sensor of the demodulation system 4 and its spatial position in the blade. The computer terminal has a dedicated data post-processing module for determining the health status of the wind turbine blade and the potential failure position of the composite material structure.

[0061] The fiber optic signal monitoring terminal monitors the structural health status of the blades. The damage that can be monitored includes but is not limited to structural damage such as debonding, cracking, and delamination that occurs during production, transportation, lifting, and service.

[0062] Example 2

[0063] This embodiment provides a method for detecting defects and damages of a wind turbine generator based on fiber grating sensing detection as described in Embodiment 1, comprising the following steps:

[0064] During the production process, transportation process, hoisting and / or operation of the blade, the optical signal transmitted by the composite material sensing unit injected into the blade body 1 is collected through the optical fiber signal detection terminal, the collected optical signal and its spatial position in the blade are correspondingly recorded through the computer terminal, and the health status of the wind turbine blade and the potential failure location of the composite material structure are determined through a dedicated data post-processing module and health judgment algorithm, thereby performing defect and damage detection of the blade throughout its life cycle from production and manufacturing to service.

[0065] Specifically, the computer terminal records the signal transmitted by the demodulation system 4, and the recorded information includes the signal amplitude collected by the composite material sensor unit each time, the spatial position information of the composite material sensor unit, and the time information, and stores it in a database, and continuously trains the data in the database through a deep learning algorithm. When an abnormal signal value is collected, the computer terminal can spontaneously make a judgment and give corresponding early warning information, thereby realizing the full life cycle monitoring of the blades during the operation of the wind turbine. Compared with the manual analysis and judgment of existing technicians, the monitoring method involved in this patent has higher accuracy, reliability, and weather resistance.

[0066] The composite material sensing unit is structurally arranged according to the shapes and sizes of different areas within the blade body 1, and is connected to other structural and non-structural materials of the blade, and is pre-buried in the blade during the production process.

[0067] Specific implementation example:

[0068] Example 1: When the blade is in the production process, the resin solidifies and releases heat, causing the glass fiber cloth to deform and wrinkle. The strain reading of the fiber grating embedded in the blade changes, thereby locating the defect and providing early warning, enabling early maintenance to avoid missed inspections.

[0069] If the fiber grating is attached after the blade is produced, it will be difficult to detect the defect and perform repairs in advance.

[0070] Example 2: When the blade debonds during operation, the fiber grating embedded in the blade captures the local characteristic strain changes of the shell, main beam and other structures and issues instructions such as load reduction and shutdown in advance to avoid the expansion of blade breakage at the failure location.

[0071] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A wind turbine based on fiber grating sensing detection, characterized in that: It includes a wind turbine blade pre-embedded with a fiber optic Bragg grating sensor, and a fiber optic signal monitoring terminal; The wind turbine blade comprises a blade body (1), and a composite material sensing unit poured into the blade body (1) during the manufacturing process of the blade body (1); the composite material sensing unit comprises a composite material (2) and a fiber Bragg grating (3) pre-buried in the composite material (2); the composite material sensing unit is a structural component integrally formed with the blade body, or a non-structural component pre-buried in the blade body; the shape and size of the composite material (2) match the corresponding area of ​​the blade body (1), and the fiber Bragg grating (3) is connected to the optical fiber signal monitoring terminal; The optical fiber signal monitoring terminal comprises a demodulation system (4) and a computer terminal. The demodulation system (4) is connected to the optical fiber grating (3) and is used to demodulate the optical signal transmitted by the optical fiber grating (3) and transmit it to the computer terminal. The computer terminal is used to process the signal transmitted by the demodulation system (4), analyze the abnormal value of the strain signal appearing in the operation cycle, judge the damage mode and health status of the blade at this time, and thus perform structural health detection of the blade.

2. A wind turbine generator based on fiber grating sensing detection according to claim 1, characterized in that: The blade body (1) is divided into a leading edge portion and a trailing edge portion, and the surface of the blade body (1) is divided into a pressure side and a suction side; the outside of the blade body (1) is wrapped by a blade shell with a continuous smooth curved surface, and the inside is a cavity structure supported by a main beam and a web.

3. A wind turbine generator based on fiber grating sensing detection according to claim 2, characterized in that: The blade body (1) is a fiber-reinforced composite material structural component.

4. A wind turbine generator based on fiber grating sensing detection according to claim 1, characterized in that: The optical fiber grating (3) in the composite material sensing unit is provided with a plurality of grating measuring points connected in series; the number of the composite material sensing units is one or more, and the composite material sensing units are distributed in different parts of the blade body (1) and are connected in parallel with each other.

5. A wind turbine generator based on fiber grating sensing detection according to claim 4, characterized in that: The distribution positions of the composite material sensing units include the main beam, the web, the leading edge, the trailing edge and / or the shell.

6. A wind turbine generator based on fiber grating sensing detection according to claim 1, characterized in that: The demodulation system (4) is used to convert the wavelength reflected by each fiber grating (3) into a strain value and transmit it to a computer terminal; the computer terminal determines the health status of the wind turbine blade and the potential failure position of the composite material structure through a data post-processing module based on the signal transmitted by each fiber grating (3) and its spatial position in the blade.

7. A wind turbine generator based on fiber grating sensing detection according to claim 1, characterized in that: The composite material (2) is a sheet or a profile, When the composite material (2) is a sheet material, the optical fiber grating (3) is located inside the composite material (2) and is co-solidified with the composite material (2); When the composite material (2) is a profile, the optical fiber grating (3) is located inside the composite material (2).

8. A wind turbine generator based on fiber grating sensing detection according to claim 1, characterized in that: The composite material (2) comprises a reinforcing material and a matrix material, wherein the reinforcing material is glass fiber, carbon fiber, basalt fiber or organic fiber; The matrix material is a synthetic resin, which is a thermosetting resin or a thermoplastic resin.

9. A wind turbine generator based on fiber grating sensing detection according to claim 1, characterized in that: The computer terminal is used to record the signal transmitted by the demodulation system (4), and the recorded information includes the signal amplitude collected by the composite material sensor unit each time, as well as the spatial position information, time information and abnormal state information of the composite material sensor unit, and is stored in a database; The computer terminal continuously trains the data in the database through a deep learning algorithm to build an abnormal warning deep learning model for abnormal detection of the data collected by the composite material sensor unit; when an abnormal signal value is collected, the computer terminal makes an abnormal judgment and gives corresponding warning information, thereby realizing the full life cycle monitoring of the blades during the operation of the wind turbine. Compared with the manual analysis and judgment of existing technicians, the monitoring method involved in this patent has higher accuracy, reliability and weather resistance.

10. A method for detecting defects and damages of a wind turbine generator based on fiber grating sensing detection according to any one of claims 1 to 9, characterized in that: The following steps are involved: During the production process, transportation process, hoisting and / or operation of the blade, the optical signal transmitted by the composite material sensing unit injected into the blade body (1) is collected through the optical fiber signal detection terminal, the collected optical signal and its spatial position in the blade are recorded correspondingly through the computer terminal, and the health status of the wind turbine blade and the potential failure position of the composite material structure are determined through a dedicated data post-processing module and a health judgment algorithm, thereby performing defect damage detection of the blade throughout its life cycle from production and manufacturing to service.

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