Wind turbine blade with segmented resistance to blade bending structure and wind power plant

Abstract

The application discloses a wind turbine blade with segmented resistance blade bending structure and a wind power generation device, which comprises a shell, a plurality of partitions and a plurality of elastic cavities; the partitions are arranged in the cavity formed by the shell at intervals, and the elastic cavities are arranged between any two partitions and extend along the length direction of the blade; each elastic cavity is in contact with the inner surface of the shell and the partitions after expansion. The application can adjust the bending degree of different parts of the blade according to the different torques of different parts of the blade, and can correspondingly adjust the expansion pressure of different elastic cavities from inside to outside by arranging a plurality of elastic cavities in the cavity of the blade, so as to resist the bending degree of each part of the blade and avoid the fracture of the blade.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade shape control technology, specifically to a wind turbine blade and a wind power generation device with a segmented structure to resist blade bending. Background Technology

[0002] Currently, wind turbines are developing towards larger sizes and higher power outputs. Due to the increased size, blade structures and loads are becoming increasingly complex, leading to more serious blade damage problems. Among the various damage mechanisms of existing wind turbine blades, buckling and fracture instability can cause the entire blade to break, sometimes even directly striking the tower and causing major safety accidents like turbine collapse. In a highly competitive market environment, how to innovate traditional blade structures at a relatively low cost, reducing blade weight and cost while achieving good buckling and fracture resistance, is a crucial technical requirement for 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 illustrate the current methods and measures used in this field to address the aforementioned technical needs, thereby demonstrating the need to continue seeking solutions.

[0004] For example, CN 114718802 A discloses an improvement method for the buckling resistance of existing horizontal axis wind turbine blades. This method includes the following steps: assessing the buckling characteristics of existing wind turbine blades with buckling problems, determining the area where the buckling occurs, designing one or more buckling-resistant reinforcing structural components based on the blade's structural characteristics in that area, performing on-site technical modifications to the buckling area, and installing the buckling-resistant reinforcing structural components to ensure the existing blade meets buckling resistance performance requirements. Using this technology, the buckling resistance of existing wind turbine blades with buckling problems can be improved through technical modifications. Improving the buckling resistance of wind turbine blades does not alter the aerodynamic shape or the original ply configuration of the blade, and therefore does not adversely affect the blade's performance. It is evident that this is an on-site reinforcement technique, a strengthening technique for localized bending resistance of the blade structure, and a measure to reinforce and improve weak points discovered after operation. It does not address how to suppress overall bending in the rear half or tip of the long blade.

[0005] For example, CN 114580247 A, a design method for a buckling-resistant reinforcement structure for horizontal axis wind turbine blades, addresses a serious damage scenario where buckling instability leads to overall blade failure, among various blade damage mechanisms. Current solutions to blade buckling involve modifying the blade's ply structure and adjusting its stiffness to prevent buckling. While this avoids buckling, it requires significant adjustments to the blade's structural design, increasing weight and cost. To address this issue, a method for analyzing, designing, and evaluating buckling-resistant reinforcement structures is proposed. This method includes the following steps: analyzing the buckling characteristics of the wind turbine blade to determine if buckling is occurring; if so, identifying the area where buckling occurs; and designing one or more buckling-resistant reinforcement components tailored to the specific characteristics of the blade structure in that area. The blades with the reinforced structural component were subjected to buckling analysis again to determine whether buckling still occurred. Based on the results of the reanalysis and evaluation, it was determined whether the modified blades met the buckling resistance performance requirements, or whether the reinforced structural component should be further improved until a satisfactory analysis and evaluation effect was achieved.

[0006] Some wind turbines increase blade stiffness by thickening the composite material in the blade layup, but this increases blade weight, thus raising manufacturing and installation costs. In terms of design, to ensure a safe distance between the blade and the tower, current blades employ a pre-bending design. For a 6MW wind turbine in the 100-meter range, the clearance distance for the blade tip pre-bending can be as high as 4 meters. However, this alters the aerodynamic characteristics of the blade to some extent, reducing the turbine's power output and severely impacting the economics of wind power generation. Regarding operational strategies, pitch control is used to reduce wind load on the wind turbine blades. While this reduces vibration, it decreases the blade's frontal area, lowering power generation efficiency. Furthermore, when facing extreme gusts or sudden changes in wind direction, the blade's pitch system, constrained by inertia, cannot react quickly enough (i.e., the inherent problem of slow frequency response), and the blade cannot avoid significant vibrations caused by extreme loads under such conditions. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a wind turbine blade and a wind power generation device with a segmented blade bending resistance structure, so as to solve the technical problem of blade bending and breakage caused by excessively large blade size in the prior art.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a wind turbine blade with a segmented anti-bending structure, the blade comprising: a shell, a plurality of partitions and a plurality of elastic cavities;

[0009] The partitions are spaced apart within the cavity formed by the housing, and the elastic cavity is disposed between any two partitions and extends along the length direction of the blade;

[0010] After each elastic cavity expands, it contacts the inner surface of the housing and the partition. Each elastic cavity is equipped with a pressure sensor to measure the pressure value of the elastic cavity in real time.

[0011] In some possible implementations, the spacing between the partitions increases sequentially from the root of the blade to the tip of the blade.

[0012] In some possible implementations, a bending distance sensor is also included, which is disposed on the outer wall of the tower in the windward direction relative to the blade tip across the wind turbine tower, for measuring the amount of bending of the blade.

[0013] The wind turbine blade also includes a fluid replenishment device disposed at the root of the blade, used to adjust the fluid volume in each section of the elastic cavity according to the amount of blade bending.

[0014] In some possible implementations, the fluid replenishment device includes: an air pump, an air replenishment line, an outlet pressure and flow transmitter, a drive motor, and an air source controller; one end of the air replenishment line is connected to the air pump, and the drive motor is mounted on the air pump; the outlet pressure and flow transmitter is electrically connected to the air source controller.

[0015] The outlet pressure and flow transmitter is used to feed back the pressure and flow rate of the outlet of the gas supply pipeline to the gas source controller;

[0016] The gas source controller is used to input control signals to the drive motor according to the pressure and flow rate at the outlet of the gas supply pipeline;

[0017] The drive motor is used to control the air pump to supply air to each section of the elastic cavity locally through the air supply pipeline according to the control signal.

[0018] In some possible implementations, it also includes: a bending load sensor disposed on the housing for measuring the load on the blade;

[0019] The air source controller is used to determine whether to add fluid to each elastic cavity based on the load, the bending amount, and the automatic control model stored in the adaptive regulator stored in the air source controller, and based on the pressure value measured by the pressure sensor on each elastic cavity segment.

[0020] When the pressure value measured by the pressure sensor on each elastic cavity is less than the pressure value that causes the bending amount of the corresponding shell of the current segment to recover, the control fluid replenishment device fills the elastic cavity with fluid to automatically adjust the expansion pressure of each elastic cavity from the inside to the outside; wherein, in the automatic control model, each elastic cavity corresponds to a pressure value that causes the bending amount of the shell of the corresponding segment to recover.

[0021] In some possible implementations, the automatic control model is obtained in the following manner:

[0022] The load of the wind turbine is obtained from the bending load sensor installed on the blade;

[0023] Obtain the ambient wind speed and the load on the wind turbine, and establish the correspondence between the ambient wind speed and the load on the wind turbine and the bending amount, respectively.

[0024] Based on the correspondence, obtain the functional relationship between the expansion pressure values ​​of the elastic cavity required to reduce or restore different bending amounts, and store the functional relationship in the adaptive regulator as an automatic control model.

[0025] In some possible implementations, each segment of the elastic cavity is provided with a filling inlet, and the fluid includes gas or liquid;

[0026] The air source controller controls the air pump to inject fluid into each section of the elastic cavity through the filling inlet according to the ambient temperature of the wind turbine, the bending amount, and the automatic control model, so as to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside; and / or,

[0027] The air source controller controls the air pump to inject fluid into each section of the elastic cavity through the filling inlet according to the atmospheric pressure where the wind turbine is located, the bending amount, and the automatic control model, so as to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside; and / or,

[0028] The air source controller controls the air pump to fill the elastic cavity into each segment through the filling inlet with fluid according to the output power of the wind turbine, the bending amount and the automatic control model, so as to automatically adjust the expansion pressure of the elastic cavity from the inside to the outside.

[0029] In some possible implementations, the blade further includes several air intake pipes disposed within the cavity formed by the housing, and extending sequentially from the blade root towards the blade tip within the cavity;

[0030] Each of the intake pipes is equipped with a check valve, which is connected to the filling inlet of the elastic cavity and is used to replenish fluid according to the amount of fluid in the elastic cavity.

[0031] Each of the elastic cavities is also equipped with an exhaust solenoid valve, which is electrically connected to the control bus of the exhaust solenoid valve. The opening and closing of each exhaust solenoid valve is controlled by the control bus of the exhaust solenoid valve.

[0032] In some possible implementations, the blade further includes an air intake pipe with a plurality of electrically controlled valves connected to the filling inlet of the elastic cavity.

[0033] The electrically controlled valve is electrically connected to the control bus of the electrically controlled valve, and the opening and closing of the electrically controlled valve is controlled through the control bus of the electrically controlled valve;

[0034] Each of the elastic cavities is also equipped with an exhaust solenoid valve, and the opening and closing of each solenoid valve is controlled by the control bus of the exhaust solenoid valve.

[0035] Secondly, embodiments of the present invention provide a wind turbine blade with a segmented structure to resist blade bending and a wind power generation device, wherein the wind power generation device includes the wind turbine blade described in the first aspect.

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

[0037] This invention provides a wind turbine blade with a segmented anti-bending structure, comprising: a shell, several partitions, and several elastic cavities; the partitions are spaced apart within the cavities formed by the shell, and the elastic cavities are disposed between any two partitions and extend along the length of the blade; each elastic cavity, after expansion, contacts the inner surface of the shell and the partitions. This invention can address the different torques and therefore different degrees of bending at different parts of the blade. By segmenting multiple elastic cavities within the blade's cavities, the expansion pressure from the inside out of different elastic cavities can be adjusted accordingly, thereby specifically resisting the bending of different parts of the blade and preventing blade breakage. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a wind turbine blade with a segmented blade bending resistance structure according to an embodiment of the present invention;

[0040] Figure 2 This is a curve showing the variation of external force load along the blade span in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the structure of a fluid replenishment device according to an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of a segmented elastic cavity with a filling inlet 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 with multiple air intake pipes according to an embodiment of the present invention.

[0044] Figure 6 This is a schematic diagram of a wind turbine blade structure with an air intake pipe according to an embodiment of the present invention;

[0045] Figure 7 The diagram shows a structural schematic of a wind power generation device with segmented blade bending resistance.

[0046] Explanation of icon numbers:

[0047] 1. Blade; 10. Shell; 11. Baffle; 12. Elastic cavity; 121. Pressure sensor; 122. Inlet; 123. Exhaust solenoid valve; 13. Bending distance sensor; 14. Fluid replenishment device; 141. Air pump; 142. Air replenishment pipeline; 143. Outlet pressure and flow transmitter; 144. Drive motor; 145. Air source controller; 15. Bending load sensor; 16. Inlet pipeline; 161a. Check valve; 161b. Electrically controlled valve;

[0048] 21. Nacelle; 22. Hub; 23. Generator; 24. Fairing; 25. Tower with tower door; 26. Wind vane and anemometer; 201. Inflation device; 202. Slip ring; 203. First connecting pipe; 204. Second connecting pipe. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Figure 1 This is a schematic diagram of a wind turbine blade with a segmented anti-bending structure according to an embodiment of the present invention, as shown below. Figure 1 As shown, the wind turbine blade 1 includes: a housing 10, several partitions 11, and several elastic cavities 12. Figure 1 Additionally, (not shown in the image) Figure 1 The white ellipse in the image indicates that the housing 10 has a certain thickness; partitions 11 are spaced apart in the cavity formed by the housing 10, and elastic cavities 12 are disposed between any two partitions 11 and extend along the length of the blade 1; after each elastic cavity 12 expands, it contacts the inner surface of the housing 10 and the partitions 11, and each elastic cavity 12 is provided with a pressure sensor 121 for measuring the pressure value of the elastic cavity 12 in real time.

[0051] In this embodiment, since the root of blade 1 is connected to the impeller hub 22, the bending stress on the cross-section gradually decreases from the blade root to the blade tip; the load generated by the external force on blade 1 gradually increases from the blade root to the blade tip. Therefore, in this embodiment, the blade 1 cavity is segmented to create several independent cavities. Independent expansion pressures are established in each independent cavity to bear and resist the bending stress loads at different positions along the span of blade 1, thus providing and generating the corresponding balance loads required for the bending loads. In addition, by setting a baffle 11 at the end cap of blade 1, the elastic cavity 12 can also be limited in its expansion along the span, preventing the elastic cavity 12 from being damaged at the opening at the blade root and causing unnecessary losses.

[0052] In this embodiment, the cavity of the blade 1 is isolated by a partition 11, that is, elastic cavities 12 are segmented within the cavity of the blade 1, so that each segment of the shell 10 can have independent expansion pressure. At the same time, the partition 11 also restricts each elastic cavity 12, so that the elastic cavity 12 can quickly form a pressure-sensitive change and obtain a rapid change in reaction force even with a small change in volume. Meanwhile, after the elastic cavity 12 is filled with fluid, the elastic cavity 12 and the fluid constitute a hydrodynamic device. After being subjected to airflow and various loads outside the blade 1, the multiple hydrodynamic devices establish a new cavity structure inside the blade 1 with a pressure greater than the natural ambient air pressure. The multiple cavity structures are supplied with air segment by segment, replenished with air segment by segment, and depressurized segment by segment, so that the internal air pressure can be automatically adjusted according to the power output of the wind turbine to adjust the expansion pressure of the elastic cavity 12 from the inside to the outside.

[0053] Specifically, in actual use, a fluid dynamic device provides fluid to the interior of each elastic cavity 12 to construct an expansion pressure space. After the blade 1 is subjected to airflow and various loads outside, the fluid dynamic device establishes a new cavity structure inside the blade 1 with a pressure greater than the ambient air pressure. The air pressure inside the new cavity structure can automatically adjust the outward expansion pressure according to the wind speed in the natural environment where the wind turbine is located. In addition, the forces and moments on the blade 1 of the entire impeller (composed of hub 22 and blade 1) are obtained by the following summation formula:

[0054] The tangential force (or circumferential force) generated by the airflow on impeller blade 1:

[0055]

[0056] Where n is the number of primitive segments of blade 1 calculated along its span (from the root to the tip), Z is the number of blades 1, t(r) is the width (chord length) of blade 1, which varies with the radius of the impeller blade 1, α is the angle of attack of blade 1, and C is the angle of attack of blade 1. A It is the lift coefficient, determined through wind tunnel testing, and ranges from 0.6 to 1.2. ρ is the airflow density.

[0057] The axial force generated by the airflow on impeller blade 1:

[0058]

[0059] Among them, C s is the dimensionless thrust coefficient, r is the radius of the segmented basic unit along the spanwise direction (from the root to the tip of blade 1) of blade 1, calculated starting from the root of blade 1, along the length of blade 1, υ is the wind speed in front of the wind turbine, and ρ is the airflow density.

[0060] The driving torque (wheel shaft torque) generated by the airflow on the impeller:

[0061]

[0062] Where r is the radius of the basic element segment of blade 1 on the circumference of the rotating wheel, and C M It is a dimensionless torque coefficient, and ρ is the air flow density.

[0063] Power generated by the airflow on the impeller:

[0064]

[0065] Among them, C P It is a dimensionless power coefficient, and ρ is the air flow density.

[0066] Using the wind speed in front of the wind turbine as a reference wind speed, the aerodynamic bending moment at the root of blade 1 is a combination of the bending moment in the flapping direction and the circumferential bending moment. The bending moment in the flapping direction is generated by the thrust, and the circumferential bending moment is caused by the circumferential force, i.e., the driving torque divided by the number of blades 1. The cross-section of blade 1 is a variable cross-section, with hollow sections and solid sections, and an airfoil section. The bending stress from the root to the tip of blade 1 is obtained by finite element calculation. The bending stress generated by gravity on the impeller blade 1 from the root to the tip is equal to the mass of the segment unit of blade 1 multiplied by the gravitational acceleration multiplied by the length of the segment unit, and then divided by the bending moment of the segment unit section to obtain the section stress. When the impeller rotates, the bending stress on blade 1 changes with the clock position and repeats cyclically.

[0067] As can be seen from the above formulas (1) to (4), the torque and force of different parts of the blade 1 are not equal, so the degree of bending of different parts is different. By setting multiple elastic cavities 12 in segments in the cavity of the blade 1, the expansion pressure of different elastic cavities 12 from the inside to the outside can be adjusted accordingly, thereby specifically resisting the bending of different parts of the blade 1 and avoiding the breakage of the blade 1.

[0068] Figure 2 This is a variation curve of external force load along the blade spanwise according to an embodiment of the present invention, such as... 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. Therefore, the spacing between the partitions 11 can be increased sequentially from the blade root to the blade tip, which saves costs, effectively resists the bending of the blade 1, and is also easy to control.

[0069] like Figure 7As shown, in some embodiments, it also includes: a bending distance sensor 13, which is disposed on the outer wall of the tower in the windward direction relative to the tip of the blade 1 across the wind turbine tower, or disposed on the inner wall of the housing 10 where each elastic cavity 12 is located, for measuring the bending amount of the blade 1; the wind turbine blade 1 also includes a fluid replenishment device 14, disposed at the root of the blade 1, for adjusting the expansion pressure in each elastic cavity 12 according to the bending amount of the blade 1.

[0070] Specifically, the bending distance sensor 13 installed on the tower wall works in conjunction with the magnet on the tip of the blade 1 to measure the bending amount of the blade 1. When the tip of the blade 1 rotates past the windward side (windward face) of the tower wall, the sensor coil on the tower wall has the largest potential when it 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 degree of bending of the blade 1, and also as one of the bases for the controller to automatically adjust the expansion pressure of the elastic cavity 12.

[0071] One principle of distance measurement is based on electromagnetic induction, converting the non-electrical quantity being measured into a change in the self-inductance or mutual inductance of an electromagnetic coil. The windward side of the metal tower (or frame) is used as part of an eddy current sensor, with the coil placed within blade 1. When an alternating high-frequency current is passed through the coil, an alternating magnetic flux φ is generated. Due to the effect of this alternating magnetic flux φ, as blade 1 rotates closer to the windward side of the tower, the coil induces a current on the metal surface and inside the tower. This induced current is called eddy current, and it is closed within the metal surface and inside the tower. The metal conductors on the tower surface and inside are abstracted as a short-circuit coil. According to Lenz's law, the alternating magnetic flux φ1 generated by this eddy current will be opposite in direction to the magnetic field generated by the coil in blade 1. This reduces the inductance of the coil; the smaller the distance δ, the greater the reduction in coil inductance, meaning φ1 resists the change in φ. Due to the effect of this eddy current magnetic field, the equivalent impedance Z of the coil will change. The degree of this 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 converting the distance δ into an electrical quantity.

[0072] The second principle of distance measurement: A permanent magnet component is embedded in blade 1, with the N or S pole of the magnet facing the tower. An induction coil (which can be a diaphragm type, with the coil embedded inside the diaphragm and the diaphragm attached to the tower wall) is set on the outer wall of the tower supporting the wind turbine. The coil acts as the mutual inductance object of the electromagnetic induction principle. The magnitude of the induced electromotive force of the coil is inversely proportional to the distance (the distance between the permanent magnet pole and the tower). The proportionality coefficient can be obtained by experimental plotting method. Several values ​​of induced electromotive force are obtained from the minimum distance (starting from the contact point) to the maximum distance between blade 1 and the tower 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 proportionality coefficient.

[0073] Figure 3This is a schematic diagram of the structure of a fluid replenishment device according to an embodiment of the present invention, as shown below. Figure 3 As shown, in some embodiments, the fluid replenishment device 14 includes: an air pump 141, an air replenishment pipeline 142, an outlet pressure-flow transmitter 143, a drive motor 144, and an air source controller 145. One end of the air replenishment pipeline 142 is connected to the air pump 141, and the drive motor 144 is mounted on the air pump 141. The outlet pressure-flow transmitter 143 is electrically connected to the air source controller 145. The outlet pressure-flow transmitter 143 is used to feed back the pressure and flow rate of the outlet of the air replenishment pipeline 142 to the air source controller 145. The air source controller 145 is used to input a control signal to the drive motor 144 according to the pressure and flow rate of the outlet of the air replenishment pipeline 142. The drive motor 144 is used to control the air pump 141 to replenish air to each elastic cavity 12 locally through the air replenishment pipeline 142 according to the control signal. This embodiment of the invention can provide suitable fluid to each elastic cavity 12, so that the pressure generated from the inside to the outside of each elastic cavity 12 is sufficient to resist the expansion pressure caused by the bending of each part of each blade 1.

[0074] Figure 7 This is a schematic diagram of the structure of a wind power generation device with segmented blade bending resistance according to an embodiment of the invention, as shown below. Figure 7 As shown, in some embodiments, it further includes: a bending load sensor 15 disposed on the housing 10 for measuring the load on the blade 1; an air source controller 145 for determining whether to replenish fluid into each segment of the elastic cavity 12 based on the load, bending amount, and an automatic control model stored in the adaptive regulator stored in the air source controller 145, and based on the pressure value measured by the pressure sensor 121 on the elastic cavity 12; when the pressure value measured by the pressure sensor 121 on each segment of the elastic cavity 12 is less than the pressure value that would restore the bending amount of the blade 1 in the current segment, the fluid replenishment device 14 is controlled to fill fluid into each segment of the elastic cavity 12 to automatically adjust the expansion pressure of each segment of the elastic cavity 12 from the inside out; wherein, in the automatic control model, each segment of the elastic cavity 12 corresponds to a pressure value that would restore the bending amount of the corresponding segment of the housing 10.

[0075] Specifically, in the automatic control model, each elastic cavity 12 corresponds to a pressure value that restores the bending amount of the corresponding shell 10. Different positions of the blade 1 shell 10 are subjected to different forces, resulting in different bending amounts. This means that the expansion pressure value required to restore or reduce different bending amounts is different. Therefore, each elastic cavity 12 and its corresponding shell 10 will have a series of pressure values. These pressure values ​​can enable different bending amounts to be restored, that is, provide a suitable pressure value to avoid excessive expansion pressure further damaging the blade 1 shell 10, and at the same time, it can also avoid insufficient expansion pressure that cannot resist the bending of the shell 10.

[0076] In some embodiments, the automatic control model is obtained by: acquiring the load of the wind turbine from the bending load sensor 15 installed on the blade 1; acquiring the wind speed of the natural environment where the wind turbine is located and the load of the wind turbine, establishing the correspondence between the wind speed of the natural environment and the load of the wind turbine and the bending amount respectively; acquiring the functional relationship between the expansion pressure value of the elastic cavity 12 required to reduce or restore different bending amounts according to the correspondence, and storing the functional relationship in the adaptive regulator as the automatic control model.

[0077] Specifically, in actual use, the wind speed in front of the wind turbine is used as the reference wind speed. The aerodynamic bending moment at the root of blade 1 is a combination of the bending moment in the flapping direction and the circumferential bending moment. The bending moment in the flapping direction is generated by the thrust, and the circumferential bending moment is caused by the circumferential force, i.e., the driving torque divided by the number of blades 1. The cross-section of blade 1 is a variable cross-section, with hollow and solid sections. The bending stress from the root to the tip of blade 1 is obtained by finite element calculation. The bending stress generated by gravity on blade 1 from the root to the tip is equal to the mass of the segment unit of blade 1 multiplied by the gravitational acceleration multiplied by the length of the segment unit, and then divided by the bending moment of the segment unit section to obtain the section stress. When the impeller rotates, the bending stress on blade 1 changes with the clock position and repeats cyclically.

[0078] After obtaining the bending stress, the bending deformation of blade 1 under stress is calculated. For several different loads, the bending moments can be superimposed, that is, the superposition method commonly used in mechanics of materials is used to obtain the total bending deformation. This deformation needs to be corrected by the measurement data of the blade 1 distance sensor. The correction method constitutes the data correction library function in the adaptive control system and is stored in the adaptive controller for the air source controller 145 to call at any time. The blade 1 distance sensor can be arranged horizontally across the windward direction of the tower relative to the blade tip of blade 1, or it can be set in the segmented elastic cavity 12 inside blade 1. Therefore, through formulas (1), (2), (3) and (4), it can be seen that the function values ​​on the left side of the formula are proportional to the square or cube of the wind speed. At the same time, the rate of influence of wind speed change on the function derivative is quantified. That is, the expressions of the derivatives dU, dS, dM, and dP are stored in the adaptive regulator as the control law of the air source controller 145. In addition, in this embodiment, the measurement data of the ranging sensor can be used as the subtrahend for the subtraction operation. The design value of the blade 1 before bending is the minuend. The difference between them is multiplied by a correction coefficient between 0 and 1. A correction coefficient of 1 indicates that the bending deformation is completely restored, and a correction coefficient of 0 indicates that it is not restored. As a control target, the elastic cavity 12 supports the blade 1 to resist bending and tries to make the blade 1 move closer to the state before bending, but not absolutely closer.

[0079] In this embodiment, the upwind airflow (the airflow upstream of the wind turbine) does work on the blade 1. As can be seen from formulas (1) to (4), 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 the blade 1 is also proportional to the square of the airflow velocity. The corresponding torque coefficient and bending stress coefficient can be obtained with the help of the wind farm. When the blade 1 pitches to change the wind turbine output, the corresponding reduction in power output and the bending condition of the blade 1 are established by using the bending load sensor 15 installed on the blade 1 and the sensor installed on the tower wall in conjunction with the magnet a on the tip of the blade 1 to measure the distance and establish a quantitative relationship between the wind turbine output and the degree of bending. Simultaneously, air is supplied to the elastic cavity 12 inside the blade 1 housing 10 to establish an expansion pressure greater than the atmospheric pressure of the natural environment and large enough to help the blade 1 material resist bending (with the help of a ranging sensor), so that the degree of bending of the blade 1 is reduced or restored, and the corresponding expansion pressure of the elastic cavity 12 is obtained. This pressure value is stored in the adaptive bending resistance regulator as the basic basis for control regulation (or control model, forming a control algorithm).

[0080] Figure 4 This is a schematic diagram of a segmented elastic cavity with a filling inlet according to an embodiment of the present invention, as shown below. Figure 4 As shown, in some embodiments, each elastic cavity 12 is provided with a filling inlet 122, and the fluid includes gas or liquid; the air source controller 145 controls the air pump 141 to fill the elastic cavity 12 with fluid through the filling inlet 122 according to the ambient temperature of the wind turbine, the amount of bending and the automatic control model, so as to automatically adjust the expansion pressure of the elastic cavity 12 from the inside to the outside; and / or, according to the atmospheric pressure of the wind turbine, according to the amount of bending and the automatic control model, the air pump 141 is controlled to fill the elastic cavity 12 with fluid through the filling inlet 122 to automatically adjust the expansion pressure of the elastic cavity 12 from the inside to the outside; and / or, according to the power output of the wind turbine, according to the amount of bending and the automatic control model, the air pump 141 is controlled to fill the elastic cavity 12 with fluid through the filling inlet 122 to automatically adjust the expansion pressure of the elastic cavity 12 from the inside to the outside.

[0081] Specifically, after being subjected to airflow and various loads outside the blade 1, the elastic cavity 12 establishes a new cavity structure inside the blade 1 with a pressure greater than the ambient air pressure. The air pressure inside the new cavity structure can automatically adjust the outward expansion pressure according to the power output of the wind turbine and the ambient temperature. According to the gas state equation of thermodynamics in physics, pV = mRT, where 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 directly proportional to the change in air flow density, while the density is inversely proportional to the temperature (that is, the left side of formula (5) is differentiated with respect to the gas temperature, which yields the control law). In summary, it is to find the total differential of the composite function.

[0082] After being subjected to airflow and various loads outside the blade 1, the elastic cavity 12 establishes a new cavity structure inside the blade 1 that is greater than the natural ambient air pressure. The air pressure inside the new cavity structure can automatically adjust the outward expansion pressure inside the cavity according to the power output of the wind turbine, the natural ambient temperature, and the local atmospheric pressure (Equation (5) is used to find the total differential of the composite function on (T, p).

[0083] Similarly, after the blade 1 is subjected to airflow and various loads outside, the elastic cavity 12 establishes a new cavity structure inside the blade 1 with a pressure greater than the ambient air pressure. The air pressure inside the new cavity structure can automatically adjust the outward expansion pressure inside the cavity according to the power output of the wind turbine and the ambient temperature, wind speed, and local atmospheric pressure. In this embodiment, according to the gas state equation, the change in airflow temperature in the wind farm has a heating or cooling effect on the blade 1 shell 10, and the elastic cavity 12 will expand and contract accordingly. Similarly, the atmospheric pressure of the ambient environment where the wind turbine is located will also produce different pressures on the elastic cavity 12. Therefore, in this embodiment, air temperature and air pressure are used as auxiliary input parameters for the adaptive regulator feedback control to better control the expansion pressure inside the elastic cavity 12. In this embodiment, after the blade 1 is subjected to airflow and various loads outside, the hydrodynamic device establishes a new cavity structure inside the blade 1 with a pressure greater than the ambient air pressure. The air pressure inside the new cavity structure can automatically adjust the outward expansion pressure inside the cavity according to the power output of the wind turbine and the ambient temperature, wind speed, and local atmospheric pressure.

[0084] Figure 5 This is a schematic diagram of the internal structure of a wind turbine blade with multiple air intake pipes according to an embodiment of the present invention, as shown below. Figure 5 As shown, in some embodiments, the blade 1 also includes a check valve 161a on each intake pipe 16 that is connected to the filling inlet 122 of the elastic cavity 12 to replenish fluid into the elastic cavity 12; each section of the elastic cavity 12 is also provided with an exhaust solenoid valve 123, and multiple exhaust solenoid valves 123 are electrically connected to the exhaust solenoid valve 123 control bus, and the opening and closing of each exhaust solenoid valve 123 is controlled by the exhaust solenoid valve 123 control bus.

[0085] Figure 6 This is a schematic diagram of a wind turbine blade structure with an air intake pipe according to an embodiment of the present invention, as shown below. Figure 6As shown, in some embodiments, for ease of management, the blade 1 also includes an air intake pipe 16, on which several check valves 161a are provided, each connected to the filling inlet 122 of the elastic cavity 12; or, the air intake pipe 16 is provided with several electrically controlled valves 161b, each connected to the filling inlet 122 of the elastic cavity 12; the several electrically controlled valves 161b are electrically connected to an electrically controlled valve 161b control bus, which controls the opening and closing of the electrically controlled valves 161b to replenish fluid into the elastic cavity 12. When the air intake pipe 16 is provided with electrically controlled valves 161b, the several electrically controlled valves 161b replenish fluid into the elastic cavity 12 through the electrically controlled valve 161b control bus; each section of the elastic cavity 12 is also provided with an exhaust solenoid valve 123, which is controlled to open and close through an exhaust solenoid valve 123 control bus. When the internal pressure of a certain elastic cavity 12 is greater than the pressure required for the shell 10 to recover its bending amount, the fluid in the elastic cavity 12 can be discharged through the exhaust solenoid valve 123, and the expansion pressure in each elastic cavity 12 can be adjusted in real time.

[0086] In this embodiment, the opening and closing of several electrically controlled valves 161b can be uniformly controlled via the control bus of the electrically controlled valves 161b. Fluid can be individually injected into each elastic cavity 12, or the exhaust solenoid valves 123 can be uniformly controlled to allow fluid to flow out of each elastic cavity 12. This allows for individual, real-time control of the expansion pressure from the inside to the outside of each elastic cavity 12, better resisting the bending of the blade 1. Since excessive or redundant expansion pressure can also cause fatigue loads on the blade 1 shell 10, such as during windless seasons, windless periods, or long-term downtime for maintenance, this embodiment uses exhaust solenoid valves 123 connected to the elastic cavities 12 to maintain the required pressure within the elastic cavities 12.

[0087] like Figure 7 As shown, the wind power generation device with segmented blade bending resistance includes: blades 1, nacelle 21, hub 22, generator 23, fairing 24, tower 25 with tower door, wind vane and anemometer 26, etc. In this embodiment, the built-in air source is located in the nacelle 21, including an inflation device 201, slip ring 202, first connecting pipe 203, and second connecting pipe 204; the inflation device 201 is located in the nacelle 21 of the wind turbine, and the inflation device 201 is connected to the slip ring 202 installed on the hub 22 through the first connecting pipe 203, and the slip ring 202 is connected to the fluid inlet of the elastic cavity 12 through the second connecting pipe 204; the air source controller automatically controls the inflation device 201 to adaptively adjust the fluid volume in each elastic cavity 12 according to the control model and the value of the pressure sensor 121.

[0088] The wind power generation device of this invention, by segmenting elastic cavities 12 within the blade shell 10, ensures that the inner surface of the blade shell 10 is no longer subjected to atmospheric pressure, or is approximately subjected to atmospheric pressure. This allows for rigid support of the inner surface of the blade shell 10. Due to the near-rigid surface support, the inner surface of the shell 10 is no longer subject to significant reciprocating bending deformation in both directions, particularly preventing bending, denting, or buckling of the outer surface of the shell 10 towards the inner surface. Furthermore, a protective sleeve can be provided outside the elastic cavity 12. This protective sleeve, relying on the sufficient gas within the elastic cavity 12 to bulge and its own rigid surface to resist external forces and generate reaction forces, balances the pressure difference between the pressure and suction surfaces of the blade 1, preventing the blade 1 from bulging or denting. This balance prevents deformation of the pressure and suction surfaces, which is a potential contribution of the pressure energy or potential energy generated by the sufficient gas within the elastic cavity 12. This is also known as an internal structure capable of resisting blade bending, or a new structure capable of resisting blade bending. Since the blades 1 used in the wind power generation device in this embodiment have anti-bending function, the service life of the wind power generation device can be improved.

[0089] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A wind turbine blade (1) with a segmented anti-bending structure, characterized in that, The blade (1) includes: a shell (10), several partitions (11) and several elastic cavities (12); The partitions (11) are spaced apart in the cavity formed by the housing (10), and the elastic cavity (12) is disposed between any two partitions (11) and extends along the length direction of the blade (1); After each elastic cavity (12) expands, it contacts the inner surface of the shell (10) and the partition (11). Each elastic cavity (12) is provided with a pressure sensor (121) for measuring the pressure value of the elastic cavity (12) in real time. It also includes: a bending distance sensor (13), which is installed on the outer wall of the tower in the windward direction relative to the tip of the blade (1) across the wind turbine tower, for measuring the bending amount of the blade (1); the wind turbine blade (1) also includes a fluid replenishment device (14), which is installed at the root of the blade (1), for adjusting the fluid capacity in each section of the elastic cavity (12) according to the bending amount of the blade (1), and the fluid replenishment device (14) is equipped with an air source controller (145). It also includes: a bending load sensor (15), disposed on the housing (10), for measuring the load on the blade (1); The air source controller (145) is used to determine whether to add fluid to each elastic cavity based on the load, the bending amount, and the automatic control model stored in the adaptive regulator in the air source controller (145) and the pressure value measured by the pressure sensor on each elastic cavity segment; when the pressure value measured by the pressure sensor on each elastic cavity segment (12) is less than the pressure value that makes the bending amount of the corresponding shell of the current segment recover, the fluid replenishment device (14) is controlled to fill the elastic cavity segment (12) with fluid to automatically adjust the expansion pressure of each elastic cavity segment (12) from the inside to the outside; wherein, in the automatic control model, each elastic cavity segment (12) corresponds to a pressure value that makes the bending amount of the shell (10) of the corresponding segment recover; The automatic control model was obtained in the following way: The load of the wind turbine is obtained from the bending load sensor (15) installed on the blade (1); Obtain the ambient wind speed and the load on the wind turbine, and establish the correspondence between the ambient wind speed and the load on the wind turbine and the bending amount, respectively. The functional relationship between the expansion pressure values ​​of the elastic cavity (12) 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.

2. The wind turbine blade (1) with a segmented anti-bending structure according to claim 1, characterized in that, The spacing between the partitions (11) increases sequentially from the root of the blade (1) to the tip of the blade (1).

3. The wind turbine blade (1) with a segmented anti-bending structure according to claim 1, characterized in that, The fluid replenishment device (14) further includes: an air pump (141), an air replenishment pipeline (142), an outlet pressure and flow transmitter (143), and a drive motor (144); one end of the air replenishment pipeline (142) is connected to the air pump (141), and the drive motor (144) is mounted on the air pump (141); the outlet pressure and flow transmitter (143) is electrically connected to the air source controller (145); The outlet pressure and flow transmitter (143) is used to feed back the pressure and flow of the outlet of the gas supply pipeline (142) to the gas source controller (145). The gas source controller (145) is used to input a control signal to the drive motor (144) according to the pressure and flow rate at the outlet of the gas supply pipeline (142); The drive motor (144) is used to control the air pump (141) to supply air to each section of the elastic cavity (12) locally through the air supply pipeline (142) according to the control signal.

4. The wind turbine blade (1) with a segmented anti-bending structure according to claim 3, characterized in that, Each of the elastic cavities (12) is provided with a filling inlet (122), and the fluid includes gas or liquid; The air source controller (145) controls the air pump (141) to inject fluid into each segment of the elastic cavity (12) through the filling inlet (122) according to the ambient temperature of the wind turbine, the bending amount, and the automatic control model, so as to automatically adjust the expansion pressure of the elastic cavity (12) from the inside to the outside; and / or, The air source controller (145) controls the air pump (141) to inject fluid into each segment of the elastic cavity (12) through the filling inlet (122) according to the atmospheric pressure where the wind turbine is located, the bending amount, and the automatic control model, so as to automatically adjust the expansion pressure of the elastic cavity (12) from the inside to the outside; and / or, The air source controller (145) controls the air pump (141) to fill fluid into each section of the elastic cavity (12) through the filling inlet (122) according to the output power of the wind turbine, the bending amount and the automatic control model, so as to automatically adjust the expansion pressure of the elastic cavity (12) from the inside to the outside.

5. The wind turbine blade (1) with a segmented anti-bending structure according to claim 4, characterized in that, The blade (1) also includes several air intake pipes (16), which are disposed in the cavity formed by the housing (10) and extend sequentially from the root of the blade (1) toward the tip within the cavity; Each of the intake pipes (16) is provided with a check valve (161a), which is connected to the filling port (122) of the elastic cavity (12) and is used to replenish fluid according to the contents of the elastic cavity (12); Each elastic cavity (12) is also provided with an exhaust solenoid valve (123). The exhaust solenoid valve (123) is electrically connected to the control bus of the exhaust solenoid valve (123). The opening and closing of each exhaust solenoid valve (123) is controlled by the control bus of the exhaust solenoid valve (123).

6. The wind turbine blade (1) with a segmented anti-bending structure according to claim 4, characterized in that, The blade (1) also includes an air intake pipe (16), on which a plurality of electrically controlled valves (161b) are provided, and the electrically controlled valves (161b) are respectively connected to the filling inlet (122) of the elastic cavity (12); The electrically controlled valve (161b) is electrically connected to the control bus of the electrically controlled valve (161b), and the opening and closing of the electrically controlled valve (161b) are controlled through the control bus of the electrically controlled valve (161b); Each elastic cavity (12) is also provided with an exhaust solenoid valve (123), and the opening and closing of each solenoid valve are controlled by the control bus of the exhaust solenoid valve (123).

7. A wind power generation device (2) with resistance to blade (1) bending, characterized in that, The wind power generation device includes the wind turbine blade (1) as described in any one of claims 1-6.

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