Wind turbine device and control method for adaptively adjusting resistance to wind turbine blade bending

Abstract

The present invention discloses a wind turbine device and control method for adaptively adjusting and resisting the bending of wind turbine blades. The wind turbine device includes: a blade, an air source, an air source controller, a bending distance sensor, and an adaptive regulator disposed in the air source controller. The blade includes a housing, a plurality of partitions, and a plurality of elastic cavities. The partitions are disposed within the housing at intervals to divide the housing into a plurality of closed cavities, and the elastic cavities are disposed within the closed cavities. A pressure sensor is disposed on the elastic cavity for measuring the pressure value within the elastic cavity. The bending distance sensor is disposed on the blade housing for measuring the amount of bending of the blade. The air source controller controls the air source to fill the elastic cavity with fluid according to a control model stored in the adaptive regulator, automatically adjusting the expansion pressure of the elastic cavity from the inside out. The present invention can adaptively adjust the expansion pressure of each elastic cavity from the inside out, accurately resisting the degree of bending of various parts of the blade.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine blade shape control, and in particular to a wind turbine device and a control method for adaptively adjusting and resisting bending of wind turbine blades. Background Art

[0002] Currently, wind turbines are developing in the direction of larger size and higher power. As the size increases, the blade structure and loads are becoming increasingly complex, leading to increasingly serious blade damage problems. Among the various damage mechanisms of existing wind turbine blades, structural buckling and fracture instability can lead to the entire blade breaking, and some even directly sweeping the tower, causing the entire machine to collapse and cause a major safety accident. In the fierce market competition environment, how to carry out technological innovation on traditional structural blades at the lowest possible cost, reduce blade weight and cost, and achieve good anti-buckling and anti-fracture performance is a key technical requirement of the blade design industry. Blade quality and performance are of great significance to the healthy development of the wind power industry.

[0003] Examples are given to reflect the current methods and measures in this field to solve the above technical needs, thereby illustrating the need to continue to seek solutions.

[0004] For example, CN114718802A discloses an improved method for the anti-buckling phenomenon of currently in-service horizontal axis wind turbine blades. The method includes the following steps: evaluating the buckling characteristics of currently in-service wind turbine blades with buckling problems, determining the area where the blade buckling phenomenon occurs, and designing a single or multiple anti-buckling reinforcement structural components based on the blade structural characteristics in the area, performing on-site technical transformation work on the blade buckling area, and installing anti-buckling reinforcement structural components to ensure that the currently in-service blades meet the anti-buckling performance requirements. Using this technology, the anti-buckling performance of wind turbine blades that are currently in service and have buckling problems can be improved through technical transformation. The anti-buckling performance of wind turbine blades is improved without changing the aerodynamic shape and original layup of the blades, and will not have a negative impact on the performance of the blades. It can be seen that this is an on-site reinforcement technical measure, which is an enhancement technical measure for the local bending resistance of the blade structure. It is a measure to strengthen and improve the weak points found after operation. It does not involve how to suppress the overall bending of the rear half or end of the long blade.

[0005] For example, CN114580247A discloses a method for designing a buckling-resistant reinforcement structure for horizontal-axis wind turbine blades. Among the various damage mechanisms of blades, buckling instability in the structure, which in turn leads to overall blade damage, is a serious damage scenario. The current solution to the blade buckling problem is to modify the blade ply structure and adjust the blade stiffness to avoid buckling. While this approach can prevent buckling, it requires significant adjustments to the blade's structural design, increasing the weight and cost of the blade. To address this issue, a method for analyzing, designing, and evaluating a buckling-resistant reinforcement structure is proposed without making significant changes to the blade's main structure, weight, and cost. The method includes the following steps: analyzing the buckling characteristics of a wind turbine blade to determine whether buckling has occurred; if so, determining the area where the buckling has occurred; and designing one or more buckling-resistant reinforcement components based on the blade's structural characteristics in that area. The blade with the enhanced structural component installed is re-analyzed for buckling to determine whether buckling still occurs in the modified blade. Based on the results of the re-analysis and evaluation, it is determined whether the modified blade meets the anti-buckling performance requirements, or the enhanced structural component is further improved until satisfactory analysis and evaluation results are achieved.

[0006] To address the significant vibration and deformation of wind turbine blades, current methods include increasing the thickness of the blade composite material in the blade layup to improve blade stiffness. However, this approach increases blade weight, thereby increasing the manufacturing and installation costs of the wind turbine. Regarding design, to ensure a safe distance between the blades and the tower, current blades are pre-bent. For a 6MW wind turbine in the 100-meter range, the tip clearance of the pre-bent blades can be as much as 4 meters. However, this practice alters the aerodynamic characteristics of the blades, thereby reducing the turbine's power output and severely impacting the economic viability of wind power generation. Regarding operational strategies, wind turbine blades are pitch-controlled to reduce wind loads. While this approach can reduce vibration, it also reduces the windward area of the wind turbine blades, resulting in reduced power generation efficiency. Furthermore, in the face of extreme gusts and sudden changes in wind direction, the blade pitch system is constrained by inertia and has little time to react (i.e., the inherent problem of slow frequency response), making it impossible for the blades to avoid the significant vibration caused by these extreme loads. Summary of the Invention

[0007] In view of this, an object of the embodiments of the present invention is to provide a wind turbine device and control method capable of adaptively adjusting the resistance to bending of wind turbine blades, so as to solve the technical problem in the prior art of blade bending and breaking due to excessive blade size.

[0008] To achieve the above-mentioned object, in a first aspect, the present invention provides a wind turbine device capable of adaptively adjusting resistance to bending of wind turbine blades, the wind turbine device comprising: a blade, an air source, an air source controller, a bending distance sensor, and an adaptive regulator disposed in the air source controller;

[0009] The blade includes a shell, a plurality of partitions and a plurality of elastic cavities. The partitions are arranged at intervals in the shell to divide the shell into a plurality of closed cavities. Each closed cavity is provided with an elastic cavity, and each closed cavity has an independent expansion pressure. A pressure sensor is provided on each elastic cavity for measuring the pressure value on the elastic cavity.

[0010] The bending distance measuring sensor is arranged on the outer wall of the tower relative to the tip of the blade passing through the tower in the windward direction, and is used to measure the bending amount of the blade;

[0011] The air source controller is used to control the air source to fill the elastic cavity with fluid according to the bending amount and the automatic control model stored in the adaptive regulator to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside.

[0012] In some possible implementations, the wind turbine device further includes: a bending load sensor, disposed on the housing of the blade, for measuring the load on the blade;

[0013] The air source controller is further configured to control the air source to fill the elastic cavity with fluid according to the load, the bending amount, and the automatic control model stored in the adaptive regulator to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside.

[0014] In some possible embodiments, the lengths of several of the closed cavities increase successively from the root of the blade to the tip of the blade; the automatic control model is a functional relationship between the expansion pressure values of each elastic cavity required to reduce or restore different bending amounts; the functional relationship refers to a set of pressure values corresponding to each elastic cavity that restores or reduces the bending amount of the shell in which the corresponding closed cavity is located.

[0015] In some possible implementations, the air source is provided at an open position at the root of the blade, and includes: an air pump, an air supply pipeline, an outlet pressure flow transmitter, and a drive motor; one end of the air supply pipeline is connected to the air pump, and the drive motor is mounted on the air pump; the outlet pressure flow transmitter is electrically connected to the air source controller;

[0016] The outlet pressure flow transmitter is used to feed back the pressure flow of the outlet of the air supply pipeline to the air source controller;

[0017] The air source controller is used to input a control signal to the driving motor according to the pressure flow of the outlet of the air supply pipeline;

[0018] The driving motor is used to control the air pump to locally supply air to each elastic cavity through the air supply pipeline according to the control signal.

[0019] In some possible embodiments, an air inlet pipe is provided on the blade, one end of the air inlet pipe is connected to the air outlet, and the other end passes through the plug partition and extends inside the housing along the blade root toward the blade tip;

[0020] The check valve or the electrically controlled valve on the air intake line is connected to the inflation port of the elastic cavity, and is used to replenish fluid into the elastic cavity according to the pressure value measured by the pressure sensor on the elastic cavity.

[0021] In some possible implementations, an exhaust solenoid valve is further provided on the elastic cavity, and the exhaust solenoid valve is electrically connected to the exhaust solenoid valve control circuit, and the opening and closing of each exhaust solenoid valve is respectively controlled by the exhaust solenoid valve control circuit.

[0022] In a second aspect, the present invention provides a control method for adaptively adjusting resistance to bending of wind turbine blades, the control method being applicable to the wind turbine device according to any one of claims 1 to 4, the control method being executed by the air source controller, and comprising:

[0023] Acquiring an automatic control model and storing the automatic control model in the adaptive regulator;

[0024] obtaining a bending amount of the blade from a bending distance measuring sensor provided on the blade;

[0025] According to the bending amount and the automatic control model, the air source is controlled to fill the fluid into each elastic cavity respectively to adjust the expansion pressure of the elastic cavity from the inside to the outside.

[0026] In some possible implementations, obtaining the automatic control model specifically includes:

[0027] Obtaining the load of the wind turbine by using a bending load sensor provided on the blade;

[0028] Obtaining a natural environment wind speed in which the wind turbine is located and a load of the wind turbine, and establishing corresponding relationships between the natural environment wind speed and the load of the wind turbine and the bending amount respectively;

[0029] A functional relationship between the expansion pressure values of the elastic cavity required to reduce or restore different bending amounts is obtained according to the corresponding relationship, and the functional relationship is stored in the adaptive regulator as an automatic control model.

[0030] In some possible implementations, the control method further includes:

[0031] According to the ambient temperature of the wind turbine, the bending amount and the automatic control model, the air source is controlled to fill the elastic cavity with fluid to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside; and / or,

[0032] According to the atmospheric pressure of the wind turbine, the bending amount and the automatic control model, the air source is controlled to fill the elastic cavity with fluid to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside; and / or,

[0033] According to the output power of the wind turbine, the bending amount and the automatic control model, the air source is controlled to fill the elastic cavity with fluid to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside.

[0034] In some possible implementations, the control method further includes:

[0035] When the blades of the wind turbine are in a feathered blade posture, zero power output or shutdown state, if the outer surface of the blade is covered with ice, the air source controller controls the elastic cavity to maintain the original expansion pressure from the inside out.

[0036] The above technical solution has the following beneficial effects:

[0037] The present invention provides a wind turbine device and control method for adaptively adjusting and resisting the bending of wind turbine blades. The wind turbine device includes: a blade, an air source, an air source controller, a bending distance sensor, and an adaptive regulator disposed in the air source controller. The blade includes a shell, a plurality of partitions, and a plurality of elastic cavities. The partitions are disposed within the shell at intervals to divide the shell into a plurality of closed cavities, and the elastic cavities are disposed within the closed cavities. A pressure sensor is disposed on the elastic cavity for measuring the pressure value on the elastic cavity. The bending distance sensor is disposed on the blade shell for measuring the bending amount of the blade. The air source controller controls the air source to fill the elastic cavity with fluid according to a control model stored in the adaptive regulator, automatically adjusting the expansion pressure of the elastic cavity from the inside out. The present invention can adaptively adjust the expansion pressure of each elastic cavity from the inside out, accurately resisting the degree of bending of various parts of the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0039] Figure 1 1 is a schematic structural diagram of a wind turbine device for adaptively adjusting resistance to bending of wind turbine blades provided by the present invention;

[0040] Figure 2 This is a schematic structural diagram of a wind turbine blade provided by the present invention;

[0041] Figure 3 1 is a schematic structural diagram of a gas source according to an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of a structure of an elastic cavity with an inflation port according to an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of the internal structure of a wind turbine blade including multiple air inlet ducts according to an embodiment of the present invention;

[0044] Figure 6 Schematic diagram of the internal structure of a wind turbine blade including an air intake duct according to an embodiment of the present invention;

[0045] Figure 7 This is a structural schematic diagram of an elastic cavity with an exhaust solenoid valve according to an embodiment of the present invention;

[0046] Figure 8 This is a flow chart of a control method for adaptively adjusting and resisting bending of a wind turbine blade 1 provided by the present invention;

[0047] Figure 9 This is a flow chart for obtaining an automatic control model provided by the present invention. Description of the drawings:

[0049] 1. Blade; 2. Air source; 3. Bending distance sensor; 4. Bending load sensor; 5. Nacelle; 6. Hub; 7. Generator; 8. Fairing; 9. Tower; 10. Wind vane and anemometer;

[0050] 11. Housing; 12. Partition; 13. Enclosed cavity; 14. Inlet pipe; 141a. Check valve; 141b. Electronically controlled valve; 15. Exhaust solenoid valve; 16. Image sensor; 17. Elastic cavity; 171. Pressure sensor; 172. Inlet port;

[0051] 20. Air source controller; 21. Air pump; 22. Air supply pipeline; 23. Outlet pressure flow transmitter; 24. Drive motor;

[0052] 201, inflation device; 202, slip ring; 203, first connecting pipeline; 204, second connecting pipeline;

[0053] a. Magnetic steel. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] Figure 1 1 is a schematic structural diagram of a wind turbine device for adaptively adjusting and resisting bending of wind turbine blades provided by the present invention. Figure 2 This is a schematic structural diagram of a wind turbine blade provided by the present invention. Figure 3 Schematic diagram of the structure of a gas source according to an embodiment of the present invention. Figures 1 to 3 As shown, the wind turbine device includes: a blade 1, an air source 2, an air source controller 20, a bending distance sensor 3, and an adaptive regulator arranged in the air source controller 20; the blade 1 includes a shell 11, a plurality of partitions 12 and a plurality of elastic cavities, the partitions 12 are arranged at intervals in the shell 11 to divide the shell 11 into a plurality of closed cavities 13, and the elastic cavity 17 is arranged in the closed cavity 13; a pressure sensor 171 is provided on the elastic cavity 17 for measuring the pressure value on the elastic cavity 17; the bending distance sensor 3 is arranged on the outer wall of the tower 9 that passes across the windward direction of the tower 9 relative to the blade tip of the blade 1 or on the inner wall of each closed cavity 13 for measuring the bending amount of the blade 1; the air source controller 20 controls the air source 2 to fill the elastic cavity with fluid according to the automatic control model stored in the adaptive regulator to automatically adjust the expansion pressure of the elastic cavity 17 from the inside to the outside.

[0056] In this embodiment, in the automatic control model, each elastic cavity 17 corresponds to a pressure value for restoring the bending amount of the shell 11 of the corresponding section. Different positions of the blade 1 shell 11 are subjected to different forces, resulting in different bending amounts, so that different expansion pressure values are required to restore or reduce different bending amounts. Therefore, each section of the elastic cavity 17 and its corresponding shell 11 will have a series of pressure values. These pressure values can restore different bending amounts, that is, provide a suitable pressure value to avoid excessive expansion pressure further damaging the blade 1 shell 11, and also avoid the expansion pressure being too small to play a role in resisting the bending of the shell 11.

[0057] Of course, the wind turbine device may also include a nacelle 5, a hub 6, a generator 7, a shroud 8, a tower with a tower door 9, a wind vane and anemometer 10, etc. In this embodiment, the air source 2 is disposed in the nacelle 5 and includes an air charging device 201, a slip ring 202, a first connecting pipe 203, and a second connecting pipe 204. The air charging device 201 is disposed in the nacelle 5 of the wind turbine. The air charging device 201 is connected to the slip ring 202 mounted on the hub 6 via the first connecting pipe 203. The slip ring 202 is connected to the fluid charging port 172 of the elastic cavity 17 via the second connecting pipe 204. The air source controller 20 automatically controls the air charging device 201 according to the automatic control model and the value of the pressure sensor 171 to adaptively adjust the volume of the fluid in each elastic cavity 17.

[0058] Specifically, since the root of the blade 1 is connected to the impeller hub 6, the bending stress borne by the cross section gradually decreases from the root to the tip of the blade; the load generated by the external force on the blade 1 gradually increases from the root to the tip of the blade 1; therefore, this embodiment divides the cavity of the blade 1 into sections, establishes a number of closed cavities 13, and establishes independent expansion pressures in the independent closed cavities 13, which respectively bear and simultaneously resist the bending stress loads at different positions in the span of the blade 1, that is, correspondingly provide and generate the balance load required for the corresponding bending load. In addition, by providing the partition 12, the expansion of the elastic cavity 17 in the span space can also be limited, and the partition 12 at the plug can also prevent the elastic cavity 17 from being damaged from the opening at the root of the blade, causing unnecessary losses.

[0059] In this embodiment, the cavity of the blade 1 is isolated by the partition 12 to obtain multiple closed cavities 13, so that each closed cavity 13 can have an independent pressure; it can also limit each elastic cavity 17, so that the volume change of the elastic cavity 17 is very small, so as to quickly form a sensitive change in pressure and obtain a rapid change in the reaction force.

[0060] At the same time, after the elastic cavity 17 is filled with fluid, the elastic cavity 17 and the fluid constitute a fluid dynamic device. After being affected by airflow and various loads outside the blade 1, the multiple fluid dynamic devices establish a new cavity structure inside the blade 1 with an air pressure greater than the natural environment pressure, and perform segmented air supply, segmented air replenishment and segmented air release on the multi-section new cavity structure, so that the internal air pressure can automatically adjust the expansion pressure of the elastic cavity from the inside to the outside according to the power output of the wind turbine.

[0061] In some embodiments, the wind turbine device may further include a bending load sensor 4 disposed on the housing 11 of the blade 1 for measuring the load on the blade 1. The air source controller 20 is further configured to control the air source 2 to fill the elastic cavity 17 with fluid based on the load and bending of the blade 1 and the automatic control model stored in the adaptive regulator, thereby automatically adjusting the expansion pressure of the elastic cavity 17 from the inside out.

[0062] Specifically, different load amounts exert different forces and moments on the blade 1, that is, different bending stresses will be generated, and different bending stresses will produce different bending deformations. Similarly, different wind speeds will also produce different bending stresses on the blade 1, and then produce different bending deformations. The moments can be superimposed, that is, the general superposition method of material mechanics can be used to obtain the above-mentioned total bending deformation. The air source controller 20 will control the air source 2 to fill the elastic cavity 17 with fluid according to the automatic control model stored in the adaptive regulator of the total deformation, so as to separately and independently adjust the expansion pressure of the elastic cavity 17 from the inside to the outside.

[0063] like Figure 2 As shown, in some embodiments, the load generated by the external force on the blade 1 gradually increases from the blade root to the blade tip, that is, the external force load gradually increases along the span of the blade 1 except for the blade tip, so the lengths of the multiple closed cavities 13 increase successively from the root of the blade 1 to the blade tip, and the automatic control model is a functional relationship between the expansion pressure values of each elastic cavity required to reduce or restore different bending amounts; this numerical relationship means that each elastic cavity 17 corresponds to a set of pressure values that restore or reduce the bending amount of the shell 11 where the corresponding closed cavity 13 is located, that is, in the automatic control model, each elastic cavity 17 has a corresponding pressure value set. Each elastic cavity 17 corresponds to a set of pressure values for restoring the bending amount of the shell 11 of the corresponding section. Because different positions of the blade shell 11 are subjected to different forces and the resulting bending amounts are different, the expansion pressure values required to restore or reduce different bending amounts are different. Therefore, each section of the elastic cavity 17 and the shell 11 where its corresponding closed cavity 13 is located will have a series of pressure values. These pressure values can restore different bending amounts, that is, provide a suitable pressure value to avoid excessive expansion pressure further damaging the blade 1 shell 11, and also avoid the expansion pressure being too small to play a role in resisting the bending of the shell 11.

[0064] The embodiment of the present invention establishes independent expansion pressure in the independent closed cavity 13, so as to bear and resist the bending stress loads at different positions of the blade 1 in the span direction respectively, that is, to provide and generate the corresponding balanced load required for the bending load, which saves costs, can well resist the bending of the blade 1, and is also easy to control.

[0065] Figure 3 Schematic diagram of the structure of a gas source according to an embodiment of the present invention. Figure 3 As shown, in some embodiments, the air source 2 is set at an open position at the root of the blade 1, and includes: an air pump 21, an air supply pipeline 22, an outlet pressure flow transmitter 23 and a drive motor 24; one end of the air supply pipeline 22 is connected to the air pump 21, and the drive motor 24 is installed on the air pump 21; the outlet pressure flow transmitter 23 is electrically connected to the air source controller 20; the outlet pressure flow transmitter 23 is used to feed back the pressure flow of the outlet of the air supply pipeline 22 to the air source controller 20; the air source controller 20 is used to input a control signal to the drive motor 24 according to the pressure flow of the outlet of the air supply pipeline 22; the drive motor 24 is used to control the air pump 21 to supply air to each elastic cavity locally through the air supply pipeline 22 according to the control signal. The embodiment of the present invention can provide a suitable fluid to each elastic cavity 17, so that the pressure generated from the inside to the outside of each elastic cavity 17 is sufficient to resist the bending degree of each part of each blade 1.

[0066] Figure 4 This is a schematic diagram of a structure of an elastic cavity with an inflation port according to an embodiment of the present invention; Figure 5 FIG. 1 is a schematic structural diagram of a wind turbine blade with an air inlet pipe according to an embodiment of the present invention; Figure 4 and Figure 5 As shown, in some embodiments, an air intake pipe 14 is provided on the blade 1, one end of the air intake pipe 14 is connected to the air outlet, and the other end passes through the plug partition 12 and extends in the cavity of the blade 1 along the root of the blade 1 toward the tip of the blade; the check valve 141a or the electric control valve 141b on the air intake pipe 14 is connected to the inflation port 172 of the elastic cavity 17, and is used to replenish fluid into the elastic cavity 17 according to the pressure value measured by the pressure sensor 171 on the elastic cavity 17.

[0067] Figure 5 FIG. 1 is a schematic diagram of the internal structure of a wind turbine blade including multiple air inlet pipes according to an embodiment of the present invention. Figure 5As shown, optionally, there can be multiple intake pipes 14, which extend sequentially from the root of the blade 1 toward the tip of the blade within the blade cavity. The check valve 141a on each intake pipe 14 is connected to the charging port 172 of the elastic cavity 17, respectively, for replenishing fluid into the elastic cavity 17 based on the pressure value measured by the pressure sensor 171 on the elastic cavity 17. Each elastic cavity 17 is also provided with an exhaust solenoid valve 15, and the exhaust solenoid valve 15 control circuit controls the opening and closing of the exhaust solenoid valve 15. In this embodiment, each elastic cavity 17 can be provided with a separate intake pipe 14 to facilitate the independent control of the pressure from the inside to the outside of each elastic cavity 17.

[0068] Figure 6 FIG. 1 is a schematic diagram of the internal structure of a wind turbine blade including an air inlet pipe according to an embodiment of the present invention. Figure 6 As shown, optionally, to facilitate unified management, the blade 1 may further be provided with an air intake pipe 14, on which a plurality of electrically controlled valves 141b are provided. The electrically controlled valves 141b are respectively connected to the air filling ports 172 of the elastic cavity 17. Each electrically controlled valve 141b is individually controlled by a control circuit of the electrically controlled valve 141b (e.g., an electrically controlled valve control bus) to replenish fluid into the elastic cavity 17. In this embodiment of the present invention, the opening and closing of the plurality of electrically controlled valves 141b can be uniformly controlled by the electrically controlled valve 141b control bus to individually control the pressure from the inside to the outside of each elastic cavity 17.

[0069] Figure 7 FIG. 1 is a structural diagram of an elastic cavity with an exhaust solenoid valve according to an embodiment of the present invention. Figure 7 As shown, in some embodiments, each elastic cavity 17 is further provided with an exhaust solenoid valve 15, and the opening and closing of each solenoid valve is controlled by a control bus of the exhaust solenoid valve 15. The exhaust solenoid valve 15 can adjust the fluid within the elastic cavity 17 at any time, that is, the expansion pressure of each elastic cavity 17 from the inside out can be controlled in real time. Because excessive or redundant expansion pressure can also cause fatigue loads on the shell 11 of the blade 1, such as during the windless season, windless period, or long shutdown and maintenance period of the wind farm, this embodiment provides an exhaust solenoid valve 15 connected to the elastic cavity 17 to maintain the required pressure in the elastic cavity 17 space.

[0070] In addition, if Figure 1As shown, in the embodiment of the present invention, an image sensor 16 and a vibration sensor (not shown in the figure) can also be provided on the blade 1, which are electrically connected to the air source 2 respectively; the image sensor 16 is used to observe the bending amplitude and bending direction of the wind turbine blade 11 in real time, and feed back the observation signal to the air source controller 20, and the vibration sensor is used to monitor the vibration signal of the blade 1 in real time, and feed back the vibration signal to the air source controller 20, and the air source controller 20 is used to calculate the real-time inflation volume according to the feedback observation signal and vibration signal in real time, so as to adjust the capacity of the fluid in the elastic cavity in real time.

[0071] Example 2

[0072] Figure 8 This is a flow chart of a control method for adaptively adjusting the resistance to wind turbine blade bending provided by the present invention. Figure 8 As shown, the control method is applicable to the wind turbine device described in Example 1, and includes the following steps:

[0073] S1, obtaining an automatic control model and storing the automatic control model in an adaptive regulator in a controller;

[0074] Specifically, in this embodiment, before each wind turbine is put into use, an automatic control model is created and stored in the adaptive regulator as a basis for automatically controlling the expansion pressure in each elastic cavity.

[0075] S2, measuring the bending amount of the blade 1 by using the bending distance measuring sensor 3 provided on the blade 1;

[0076] Specifically, the bending distance sensor 3 installed on the wall of the tower 9 cooperates with the magnet a on the tip of the blade 1 to measure the distance and obtain the bending amount of the blade 1. When the tip of the blade 1 rotates and passes the windward direction (windward side) of the tower 9 wall, the potential induced by the sensor coil on the wall of the tower 9 is the largest when the distance is closest. A one-to-one correspondence is established between the induced potential and the distance between them, which serves as the basis for measuring the bending degree of the blade 1, and also serves as one of the bases for the controller to automatically adjust the expansion pressure of the elastic cavity.

[0077] One of the distance measurement principles utilizes electromagnetic induction to convert non-electrical quantities into changes in the self-inductance or mutual inductance of electromagnetic coils. The windward surface of the metal tower 9 (or tower frame) serves as part of an eddy-current sensor. A coil is placed in the blade 1. When an alternating high-frequency current flows through the coil, an alternating magnetic flux φ is generated. Due to this alternating magnetic flux, when the blade 1 rotates close to the windward surface of the tower 9, the coil facing the tower 9 generates an induced current on the metal surface and interior of the tower 9. This current, known as an eddy current, is closed within the metal surface and interior of the tower 9, abstracting the metal conductor on the surface and interior of the tower 9 as a short-circuited coil. According to Lenz's law, the alternating magnetic flux φ1 generated by this eddy current opposes the magnetic field generated by the coil in the blade 1, reducing the coil's inductance. The smaller the distance δ, the greater the reduction in coil inductance; in other words, φ1 resists changes in φ. Due to the eddy current magnetic field, the coil's equivalent impedance Z changes. The degree of change is related to the distance δ between the two and is a single-valued function: Z = F(δ). The measuring circuit converts the change in impedance into a change in voltage, thereby achieving the purpose of converting the distance δ into electrical quantity.

[0078] The second principle of distance measurement: a permanent magnetic component is embedded in the blade 1, and the N pole or S pole of the magnetic pole faces the tower 9. An induction coil is set on the outer wall of the tower 9 of the wind turbine bearing structure (it can be a diaphragm type, with the coil buried inside the diaphragm, and the diaphragm is attached to the wall of the tower 9). The coil serves as the mutual induction object of the electromagnetic induction principle. The magnitude of the coil induced potential is inversely proportional to the spacing (the spacing between the permanent magnetic pole and the tower 9). The proportional coefficient can be obtained by using the test point method. Several values of the induced potential are obtained from the minimum spacing (starting from contact) to the maximum spacing between the blade 1 and the tower 9 wall when there is no wind. The test points are connected to form a curve, and the slope of the curve is used as its proportional coefficient.

[0079] S3, the controller controls the air source 2 to fill the elastic cavity with fluid according to the bending amount and the automatic control model to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside.

[0080] Specifically, different bending amounts require different expansion pressures, so the controller will dynamically adjust the expansion pressure of each elastic cavity 17 according to the current air pressure value of each elastic cavity 17 measured by the pressure sensor 171 on the elastic cavity 17, according to the automatic control model, and resist the bending degree of each blade 1 in real time.

[0081] Figure 9 This is a flow chart of obtaining an automatic control model provided by the present invention, such as Figure 9 As shown, in some embodiments, obtaining the automatic control model specifically includes the following steps:

[0082] S11, measuring the load of the wind turbine by a bending load sensor provided on the blade 1;

[0083] S12, establishing the corresponding relationship between the natural environment wind speed, load and bending amount;

[0084] S13, obtaining a functional relationship between the expansion pressure values of the elastic cavity required to reduce or restore different bending amounts, and storing the functional relationship in the adaptive regulator as an automatic control model.

[0085] Specifically, the force and moment on blade 1 of the entire impeller (composed of hub 6 and blade 1) are obtained by the following summation formula:

[0086] The tangential force (or circumferential force) generated by the air flow on the impeller blade 1 is:

[0087] n blade 1 is segmented along the span direction (the length from the root of blade 1 to the tip of blade 1), the number of segmented primitives, Z blade 1 number, t(r), blade 1 width (chord length), which varies with the radius of impeller blade 1, α, blade 1 angle of attack, C A The lift coefficient, determined through wind tunnel testing, is between 0.6 and 1.2, ρ is the air flow density.

[0088] The axial force generated by the air flow on the impeller blade 1:

[0089] C s The dimensionless thrust coefficient, r blade 1 is calculated in segments starting from the root of blade 1 along the span direction (the length direction from the root of blade 1 to the tip of blade 1), and the radius of the segmented primitive segment in the length direction of blade 1, υ is the wind speed away from the front of the wind turbine, and ρ is the air flow density.

[0090] The driving torque (axle torque) generated by the air flow on the impeller:

[0091] r blade 1 calculates the radius of the segmented primitive segment on the rotating wheel circumference, C M Dimensionless moment coefficient, ρ Air flow density.

[0092] The power generated by the air flow on the impeller:

[0093] C P Dimensionless power coefficient, ρ Air flow density.

[0094] Using the wind speed ahead of the wind turbine as the reference wind speed, the aerodynamic bending moment at the root of blade 1 is a composite of the flapping-direction bending moment and the circumferential bending moment. The flapping-direction bending moment is generated by thrust, while the circumferential bending moment is caused by the circumferential force, which is the driving torque divided by the number of blades 1. Blade 1 has a variable cross-section, with hollow and solid sections, and an airfoil-shaped cross-section. Finite element calculations are used to determine the bending stress from the root to the tip of blade 1. The bending stress generated by gravity on impeller blade 1 from the root to the tip is equal to the mass of blade 1's segmented unit multiplied by the acceleration of gravity multiplied by the length of the segmented unit, divided by the bending moment of the segmented unit cross-section, resulting in the cross-sectional stress. As the impeller rotates, the bending stress on blade 1 changes with the clock position, repeating over and over again.

[0095] After obtaining the bending stress, the bending deformation of blade 1 after being subjected to the force is calculated. For several different loads, the bending moments can be superimposed, that is, the total bending deformation mentioned above is calculated using the general superposition method in material mechanics. This deformation needs to be corrected by feedback based on the measurement data of the distance sensor of blade 1. The correction method constitutes a data correction library function in the adaptive control system, which is stored in the adaptive controller and can be called at any time by the air source controller 20. The distance sensor of blade 1 can be arranged in the windward direction relative to the tip of blade 1 across the tower 9, or it can be set in the elastic cavity set in the segment inside blade 1. Therefore, it can be seen from formula (1), formula (2), formula (3) and formula (4) that the function values on the left side of the formula increase or decrease in direct proportion to the square of the wind speed or the cube of the wind speed, and also quantify the rate of influence of wind speed change on the differential of the function, that is, the expression of the differential dU, dS, dM, dP is stored in the adaptive regulator as the control law of the air source controller 20. In addition, this embodiment can use the measurement data of the ranging sensor as the subtrahend of the subtraction operation, and the design value of the blade 1 before bending as the minuend. The difference between them is multiplied by a correction coefficient between 0 and 1. The correction coefficient 1 indicates that the bending deformation is completely restored, and the correction coefficient 0 indicates no restoration. As a control target, the elastic cavity supports the blade 1 to resist bending and strives to make the blade 1 close to the state before bending, but not absolutely close.

[0096] In this embodiment, the upwind airflow (the upstream airflow of the wind turbine) passes through blade 1 to perform work. From equations (1) to (4), it can be seen that the torque generated on each blade 1 is proportional to the square of the airflow velocity and the cube of the impeller radius. The bending stress generated at the root of blade 1 is also proportional to the square of the airflow velocity. The corresponding torque coefficient and bending stress coefficient can be obtained through the wind farm. When blade 1 pitches to change the wind turbine output, the corresponding reduction in power output and the bending condition of blade 1 are measured by using a bending load sensor installed on blade 1 and a sensor installed on the wall of tower 9 in conjunction with the magnet a on the tip of blade 1 to establish a quantitative relationship between wind turbine output and bending degree. At the same time, air is supplied to the elastic cavity in the shell 11 of the blade 1 to establish an expansion pressure (with the help of a ranging sensor) that is greater than the natural atmospheric pressure and large enough to help the blade 1 material resist bending, so that the bending degree of the blade 1 is reduced or restored, and the corresponding elastic cavity expansion pressure is obtained. This pressure value set is stored in the adaptive anti-bending regulator as the basic basis for control and regulation (or control model, forming a control algorithm).

[0097] In some embodiments, the control method also includes: controlling the air source 2 to fill the fluid into the elastic cavity to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside according to the ambient temperature of the wind turbine, the bending amount and the automatic control model; and / or controlling the air source 2 to fill the fluid into the elastic cavity to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside according to the atmospheric pressure of the wind turbine, the bending amount and the automatic control model; and / or controlling the air source 2 to fill the fluid into the elastic cavity 17 to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside according to the output power of the wind turbine, the bending amount and the automatic control model.

[0098] Specifically, after the blade 1 is subjected to airflow and various loads, the elastic cavity 17 establishes a new cavity structure inside the blade 1 with a pressure greater than the natural ambient pressure. The pressure inside the new cavity structure can automatically adjust the outward expansion pressure in the cavity according to the power output of the wind turbine and the natural ambient temperature. According to the gas state equation pV=mRT in physics, p is pressure, V is gas volume, m is gas mass, R is the universal gas constant, and T is gas temperature. ρ is the gas density. According to formulas (1) to (4), the function values on the left side of the formula are all proportional to the change in air flow density, while density is inversely proportional to temperature (the control law is obtained by differentiating the gas temperature on the left side of formula (5). In summary, the total differential of the composite function is obtained.

[0099] After the blade 1 is subjected to the action of airflow and various loads, the elastic cavity establishes a new cavity structure inside the blade 1 with a pressure greater than the natural environment. The pressure inside the new cavity structure can automatically adjust the outward expansion pressure in the cavity according to the power output of the wind turbine, the natural environment temperature and the local atmospheric pressure (Equation (5) calculates the total differential of the composite function with respect to (T, p)).

[0100] Similarly, after blade 1 is subjected to airflow and various loads, the elastic cavity establishes a new cavity structure within blade 1 with a pressure greater than the natural ambient air pressure. The pressure within this new cavity structure automatically adjusts the outward expansion pressure within the cavity based on the wind turbine's power output, the ambient temperature, wind speed, and local atmospheric pressure. In this embodiment, according to the equation of state for gases, changes in the wind farm's airflow temperature heat or cool the blade 1 shell 11, causing the elastic cavity to expand or contract accordingly. Similarly, the atmospheric pressure of the wind turbine's natural environment also exerts varying pressures on the elastic cavity. Therefore, in this embodiment, air temperature and pressure serve as auxiliary input parameters for the adaptive regulator's feedback control to better control the expansion pressure within the elastic cavity. In this embodiment, after blade 1 is subjected to airflow and various loads, the fluid dynamic device establishes a new cavity structure within blade 1 with a pressure greater than the natural ambient air pressure. The pressure within this new cavity structure automatically adjusts the outward expansion pressure within the cavity based on the wind turbine's power output, the ambient temperature, wind speed, and local atmospheric pressure.

[0101] In some embodiments, the control method further includes: when blade 1 of the wind turbine is in a feathered blade attitude, zero power output, or shutdown state, if the outer surface of blade 1 is covered with ice, the controller controls the elastic cavity to maintain the original inside-out expansion pressure. Specifically, after the outside of blade 1 is subjected to airflow and various loads, the fluid power device establishes a new cavity structure inside blade 1 with an air pressure greater than the natural ambient pressure. The air pressure within the new cavity structure can automatically adjust the outward expansion pressure within the cavity according to the power output of the wind turbine. When the wind turbine is in a feathered blade attitude, zero power output, or shutdown state, if the outer surface of blade 1 is covered with ice, it is necessary to maintain the (inside-out) expansion pressure of the new cavity structure of blade 1.

[0102] In the embodiment of the present invention, after the outside of the blade 1 is subjected to the action of airflow and various loads, multiple fluid dynamic devices composed of fluid and elastic cavities establish a new cavity structure inside the blade 1 with an air pressure greater than that of the natural environment, and supply and replenish air in sections, so that the internal air pressure can automatically adjust the outward expansion pressure in the cavity based on factors such as the power of the wind turbine, the wind speed, temperature, and air pressure of the wind turbine, so as to resist the bending of the blade 1 in sections.

[0103] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A wind turbine device capable of adaptively adjusting resistance to bending of a wind turbine blade (1), characterized in that: The wind turbine device comprises: a blade (1), an air source (2), an air source controller (20), a bending distance sensor (3), and an adaptive regulator arranged in the air source controller (20); The blade (1) comprises: a shell (11), a plurality of partitions (12) and a plurality of elastic cavities (17); the partitions (12) are arranged at intervals in the shell (11) to divide the shell (11) into a plurality of closed cavities (13); each closed cavity (13) is provided with one elastic cavity (17); each closed cavity (13) has an independent expansion pressure; each elastic cavity (17) is provided with a pressure sensor (171) for measuring the pressure value on the elastic cavity (17); The bending distance measuring sensor (3) is arranged on the outer wall of the tower (9) in the windward direction relative to the tip of the blade (1) and is used to measure the bending amount of the blade (1); The air source controller (20) is used to control the air source (2) to respectively fill the elastic cavity (17) with fluid according to the bending amount and the automatic control model stored in the adaptive regulator, so as to independently adjust the expansion pressure of each elastic cavity (17) from the inside to the outside; The automatic control model is a functional relationship between the expansion pressure values of each elastic cavity (17) required to reduce or restore different bending amounts; the functional relationship refers to a set of pressure values corresponding to each elastic cavity (17) that restores or reduces the bending amount of the shell where the corresponding closed cavity is located.

2. The wind turbine device according to claim 1, characterized in that: The wind turbine device further comprises: a bending load sensor (4), arranged on the housing (11) of the blade (1), and used for measuring the load of the blade (1); The air source controller (20) is further configured to control the air source (2) to fill the elastic cavity (17) with fluid according to the load amount, the bending amount, and the automatic control model stored in the adaptive regulator, so as to automatically adjust the expansion pressure of the elastic cavity (17) from the inside to the outside.

3. The wind turbine device according to claim 2, characterized in that: The lengths of the plurality of closed cavities (13) increase sequentially from the root of the blade (1) to the tip of the blade (1).

4. The wind turbine device according to claim 1, characterized in that: The air source (2) is arranged at an open position at the root of the blade (1), and comprises: an air pump (21), an air supply pipeline (22), an outlet pressure flow transmitter (23) and a drive motor (24); one end of the air supply pipeline (22) is connected to the air pump (21), and the drive motor (24) is mounted on the air pump (21); the outlet pressure flow transmitter (23) is electrically connected to the air source controller (20); The outlet pressure flow transmitter (23) is used to feed back the pressure flow of the outlet of the air supply pipeline (22) to the air source controller (20); The air source controller (20) is used to input a control signal to the driving motor (24) according to the pressure flow rate at the outlet of the air supply pipeline (22); The driving motor (24) is used to control the air pump (21) to supply air locally to each elastic cavity (17) through the air supply pipeline (22) according to the control signal.

5. The wind turbine device according to claim 4, characterized in that: An air intake pipe (14) is provided on the blade (1), one end of the air intake pipe (14) is connected to the air supply pipe (22), and the other end passes through a partition (12) at the root of the blade (1) and extends inside the housing (11) along the blade root of the blade (1) toward the blade tip. The check valve or the electric control valve (141) on the air intake line (14) is connected to the inflation port (172) of the elastic cavity (17) and is used to replenish fluid into the elastic cavity (17) according to the pressure value measured by the pressure sensor on the elastic cavity (17).

6. The wind turbine device according to claim 5, characterized in that: An exhaust solenoid valve (15) is also provided on the elastic cavity (17). The exhaust solenoid valve (15) is electrically connected to a control circuit of the exhaust solenoid valve (15). The opening and closing of each exhaust solenoid valve (15) is controlled respectively by the control circuit of the exhaust solenoid valve (15).

7. A control method for adaptively adjusting the resistance to bending of a wind turbine blade (1), characterized in that: The control method is applicable to the wind turbine device according to any one of claims 1 to 6, and the control method is executed by an air source controller (20). The control method includes: Acquiring an automatic control model and storing the automatic control model in the adaptive regulator; Obtaining the bending amount of the blade (1) from a bending distance measuring sensor (3) provided on the blade (1); According to the bending amount and the automatic control model, the air source (2) is controlled to fill each elastic cavity (17) with fluid to adjust the expansion pressure of the elastic cavity (17) from the inside to the outside; the automatic control model is obtained, specifically including: Obtaining the load of the wind turbine through a bending load sensor (4) provided on the blade (1); Obtaining a natural environment wind speed in which the wind turbine is located and a load of the wind turbine, and establishing corresponding relationships between the natural environment wind speed and the load of the wind turbine and the bending amount respectively; A functional relationship between the expansion pressure values of the elastic cavity (17) required to reduce or restore different bending amounts is obtained based on the corresponding relationship, and the functional relationship is stored in the adaptive regulator as an automatic control model.

8. A control method for adaptively adjusting the resistance to bending of a wind turbine blade (1) according to claim 7, characterized in that: The control method further includes: According to the ambient temperature of the wind turbine, the bending amount and the automatic control model, the air source (2) is controlled to fill the elastic cavity (17) with fluid to automatically adjust the expansion pressure of the elastic cavity (17) from the inside to the outside; and / or, According to the atmospheric pressure of the wind turbine, the bending amount and the automatic control model, the air source (2) is controlled to fill the elastic cavity (17) with fluid to automatically adjust the expansion pressure of the elastic cavity (17) from the inside to the outside; and / or, According to the output power of the wind turbine, the bending amount and the automatic control model, the air source (2) is controlled to fill the elastic cavity (17) with fluid to automatically adjust the expansion pressure of the elastic cavity (17) from the inside to the outside.

9. A control method for adaptively adjusting the resistance to bending of a wind turbine blade (1) according to claim 7, characterized in that: The control method further includes: When the blade (1) of the wind turbine is in a feathered blade posture, zero power output or shutdown state, if the outer surface of the blade (1) is covered with ice, the air source controller (20) controls the elastic cavity (17) to maintain the original expansion pressure from the inside out.

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