Wind turbine blade with segmented blade bending resistance structure and wind power generation device

Abstract

The invention discloses a wind turbine blade with a segmented blade bending resisting structure and a wind power generation device. The wind turbine blade comprises a shell, a plurality of partition plates and a plurality of elastic cavities. The partition plates are arranged in a cavity formed by the shell at intervals, and the elastic cavity is arranged between any two partition plates and extends in the length direction of the blades. And each elastic cavity is in contact with the inner surface of the shell and the partition plate after being expanded. According to different torques of different parts of the blade, the bending degrees of the different parts are different, the multiple elastic cavities are arranged in the cavity of the blade in a segmented mode, the expansion pressure of the different elastic cavities from inside to outside can be correspondingly adjusted, then the bending degrees of all the parts of the blade are resisted in a targeted mode, and blade breakage is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of wind turbine blade shape control, and in particular to a wind turbine blade with a segmented blade bending resistance structure and a wind power generation device. Background Art

[0002] At present, wind turbines are developing in the direction of large size and high power. As the size increases, the blade structure and load become more and more complex, resulting in increasingly serious blade damage. Among the various damage mechanisms of existing wind turbine blades, the structure buckles and fractures, which lead to the overall blade fracture, and some even directly sweep the tower, causing a major safety accident of the whole machine falling down. In the fierce market competition environment, how to innovate the technology of traditional structural blades at the lowest possible cost, reduce the weight and cost of blades, and achieve good anti-buckling and anti-fracture performance is an important technical requirement of the blade design industry. The quality and performance of blades 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, CN 114718802 A, an improved method for the anti-buckling phenomenon of the blades of the horizontal axis wind turbine in service, discloses an improved method for the anti-buckling phenomenon of the blades of the horizontal axis wind turbine in service, the method comprising the following steps: evaluating the buckling characteristics of the blades of the wind turbine in service with the buckling problem, determining the area where the blade buckling phenomenon occurs, and designing a single or several anti-buckling reinforcement structural components according to the structural characteristics of the blades in the area, carrying out on-site technical transformation work on the blade buckling part, and installing the anti-buckling reinforcement structural components to achieve the performance requirements of the anti-buckling of the blades in service. With this technology, the anti-buckling performance of the wind turbine blades in service with the buckling problem can be improved through technical transformation. The anti-buckling performance of the wind turbine blades is improved without changing the aerodynamic shape and the original ply of the blades, and will not have an adverse effect on the performance of the blades. It can be seen that this is an on-site reinforcement technical measure, which is an enhanced technical measure to resist bending locally in the blade structure. It is a measure to reinforce 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, CN 114580247 A, a method for designing a buckling-resistant reinforcement structure for a horizontal axis wind turbine blade, is a serious damage situation in which the structure buckles and loses stability, which leads to the destruction of the entire blade. The current solution to the problem of blade buckling is to change the blade ply structure and adjust the stiffness of the blade to avoid the occurrence of buckling. Although this method can avoid the occurrence of buckling, it requires a large adjustment to the structural design of the blade, which increases the weight and cost of the blade. How to achieve the avoidance of buckling without making major changes to the main structure of the blade, without making major changes to the weight and cost of the blade, and propose an analysis, design and evaluation method for buckling-resistant instability reinforcement structure. The method includes the following steps: analyzing the buckling characteristics of the wind turbine blade to determine whether the blade has buckling. If buckling occurs, determine the area where the buckling occurs, and design a single or several buckling-resistant reinforcement structural components according to the structural characteristics of the blade in the area. The blades with the enhanced structural components installed are re-analyzed to determine whether buckling still occurs in the modified blades. Based on the results of the re-analysis and evaluation, it is determined whether the modified blades meet the anti-buckling performance requirements, or the enhanced structural components are further improved until satisfactory analysis and evaluation results are achieved.

[0006] Others increase the thickness of blade composite materials in the blade layer to improve the stiffness of the blade, but this method will increase the weight of the blade, thereby increasing the manufacturing and installation costs of the wind turbine. In terms of appearance design, in order to ensure a safe distance between the blade and the tower, the current blades are pre-bent. For a 6MW wind turbine of the 100-meter level, the clearance distance of the blade tip pre-bend will be as high as 4 meters, but this approach changes the aerodynamic characteristics of the blade to a certain extent, thereby reducing the power output of the wind turbine, seriously affecting the economy of wind power generation. In terms of operating strategy, the wind turbine blades are controlled by variable pitch to reduce wind loads. Although this approach can reduce vibration, the windward area of ​​the wind turbine blades is reduced, and the power generation efficiency is also reduced. At the same time, when facing extreme gusts and instantaneous changes in wind direction, the blade pitch system is constrained by inertia and has no time to respond (that is, the inherent problem of slow frequency response), and the blades cannot avoid the large-scale vibration caused by extreme loads in this case. Summary of the invention

[0007] In view of this, an object of the embodiments of the present invention is to provide a wind turbine blade and a wind power generation device having a segmented structure for resisting blade bending, so as to solve the technical problem in the prior art that blades are bent and broken due to excessive blade size.

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

[0009] The partitions are arranged at intervals in the cavity formed by the shell, and the elastic cavity is arranged between any two partitions and extends along the length direction of the blade;

[0010] After expansion, each section of the elastic cavity contacts the inner surface of the shell and the partition. A pressure sensor is provided on each section of the elastic cavity for measuring the pressure value of the elastic cavity in real time.

[0011] In some possible implementations, the intervals between the partitions increase sequentially from the blade root to the blade tip.

[0012] In some possible implementations, the invention further includes: a bending distance measuring sensor, which is arranged on the outer wall of the tower relative to the tip of the blade passing across the windward direction of the tower of the wind turbine, and is used to measure the bending amount of the blade;

[0013] The wind turbine blade further comprises a fluid replenishing device, which is arranged at the root of the blade and is used to adjust the capacity of the fluid in each section of the elastic cavity according to the bending amount of the blade.

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

[0015] 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;

[0016] The gas source controller is used to input a control signal to the driving motor according to the pressure flow rate of the outlet of the gas supply pipeline;

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

[0018] In some possible implementations, the further comprising: a bending load sensor disposed on the housing, for measuring the load of the blade;

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

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

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

[0022] Obtaining the load of the wind turbine from a bending load sensor provided on the blade;

[0023] Obtaining the natural environment wind speed in which the wind turbine is located and the 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;

[0024] The 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.

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

[0026] The air source controller controls the air pump to fill the 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 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 fill the fluid into each section of the elastic cavity through the filling inlet according to the atmospheric pressure of the wind turbine, the bending amount and the automatic control model 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 fluid into each section of the elastic cavity through the filling inlet according to the output power of the wind turbine, the bending amount and the automatic control model 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 a plurality of air inlet pipes, which are disposed in a cavity formed by the shell and extend in sequence along the blade root toward the blade tip in the cavity;

[0030] Each of the air inlet pipes is provided with a check valve, the check valve being connected to the filling inlet of the elastic cavity and being used to replenish the fluid in the elastic cavity;

[0031] An exhaust solenoid valve is also provided on each section of the elastic cavity. The exhaust solenoid valves are electrically connected to the control bus of the exhaust solenoid valves respectively, and the opening and closing of each exhaust solenoid valve are respectively controlled by the control bus of the exhaust solenoid valves.

[0032] In some possible implementations, the blade further includes an air intake pipeline, and a plurality of electrically controlled valves are disposed on the air intake pipeline, and the electrically controlled valves are respectively connected to the charging inlets of the elastic cavity;

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

[0034] An exhaust solenoid valve is also provided on each section of the elastic cavity, and the opening and closing of each solenoid valve is controlled respectively through the control bus of the exhaust solenoid valve.

[0035] In a second aspect, an embodiment of the present invention provides a wind turbine blade having a segmented structure for resisting blade bending and a wind power generation device, wherein the wind power generation device comprises the wind turbine blade according to the first aspect.

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

[0037] The present invention provides a wind turbine blade with a segmented structure for resisting blade bending, comprising: a shell, a plurality of partitions and a plurality of elastic cavities; the partitions are arranged at intervals in the cavity formed by the shell, and the elastic cavity is arranged between any two partitions and extends along the length direction of the blade; each elastic cavity contacts the inner surface of the shell and the partition after expansion. The present invention can adjust the expansion pressure of different elastic cavities from the inside to the outside of the different segments of the elastic cavity according to the different moments of different parts of the blade, so the bending degree of different parts is different, by segmenting multiple elastic cavities in the cavity of the blade, thereby specifically resisting the bending of various parts of the blade and avoiding blade breakage. 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. It is obvious that the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 is a schematic structural diagram of a wind turbine blade having a segmented structure for resisting blade bending according to an embodiment of the present invention;

[0040] Figure 2 is a curve showing a change of an external force load along the span direction of a blade according to an embodiment of the present invention;

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

[0042] Figure 4 is a schematic diagram of a segmented elastic cavity with a filling port in an embodiment of the present invention;

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

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

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

[0046] Description of Figure Numbers:

[0047] 1. Blade; 10. Shell; 11. Partition; 12. Elastic cavity; 121. Pressure sensor; 122. Filling port; 123. Exhaust solenoid valve; 13. Bending distance sensor; 14. Fluid replenishing device; 141. Air pump; 142. Air replenishing pipeline; 143. Outlet pressure flow transmitter; 144. Driving motor; 145. Air source controller; 15. Bending load sensor; 16. Inlet pipeline; 161a. Check valve; 161b. Electric control valve;

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

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0050] Figure 1 is a schematic structural diagram of a wind turbine blade having a segmented structure for resisting blade bending according to an embodiment of the present invention. Figure 1 As shown, the wind turbine blade 1 comprises: a shell 10, a plurality of partitions 11 and a plurality of elastic cavities 12 ( Figure 1 Not shown in addition, Figure 1 The white oval in the figure indicates that the shell 10 has a certain thickness); the partitions 11 are arranged at intervals in the cavity formed by the shell 10, and the elastic cavity 12 is arranged between any two partitions 11 and extends along the length direction of the blade 1; each section of the elastic cavity 12 contacts the inner surface of the shell 10 and the partition 11 after expansion, and each section of the 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 the blade 1 is connected to the impeller hub 22, 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; therefore, this embodiment divides the cavity of the blade 1 into sections, establishes several sections of independent cavities, and establishes independent expansion pressures in the independent cavities, which respectively bear and simultaneously resist the bending stress loads at different positions of the blade 1 in the span direction, that is, the corresponding balanced load required by the corresponding bending load is given and generated. In addition, by setting a partition 11 at the plug of the blade 1, the expansion limit function of the elastic cavity 12 in the span direction space can also be achieved, so as to avoid the elastic cavity 12 from the opening of the blade root, thereby damaging the elastic cavity 12 and causing unnecessary losses.

[0052] In this embodiment, the cavity of the blade 1 is isolated by the partition 11, that is, the elastic cavity 12 is set in sections in the cavity of the blade 1, so that each section of the shell 10 can have an independent expansion pressure; at the same time, the partition 11 can also play a limiting role on each elastic cavity 12, so that the elastic cavity 12 can quickly form a sensitive change in pressure when the volume change is small, and obtain a rapid change in the reaction force. At the same time, after the elastic cavity 12 is filled with fluid, the elastic cavity 12 and the fluid constitute a fluid power device. After the outside of the blade 1 is affected by airflow and various loads, the multiple fluid power devices establish a new cavity structure inside the blade 1 that is greater than the natural environment pressure, and the multiple sections of the new cavity structure are segmented for air supply, segmented air replenishment and segmented air release, so that the internal air pressure can automatically adjust the expansion pressure of the elastic cavity 12 from the inside to the outside according to the power output of the wind turbine.

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

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

[0055]

[0056] Where n is the number of primitive segments of blade 1 along the span direction (the length from the root of blade 1 to the tip of blade 1), Z is the number of blades 1, t(r) is the width (chord length) of blade 1, which varies with the radius of impeller blade 1, α is the angle of attack of blade 1, and C A is the lift coefficient, determined by wind tunnel tests and is between 0.6 and 1.2, and ρ is the air flow density.

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

[0058]

[0059] Among them, C s is the dimensionless thrust coefficient, r is the radius of the segmented elementary segment in the length direction of blade 1, 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), υ is the front wind speed away from the wind turbine, and ρ is the air flow density.

[0060] The driving torque (axle torque) generated by the air flow on the impeller:

[0061]

[0062] Where r is the radius of the primitive segment of blade 1 calculation segment on the rotating wheel circumference, C M is the dimensionless moment coefficient and ρ is the air flow density.

[0063] The power generated by air flow on the impeller:

[0064]

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

[0066] 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 synthesized by 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, that is, the driving moment divided by the number of blades 1. The cross section of blade 1 is a variable section, with a hollow section, a solid section, 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 impeller blade 1 from the root to the tip = the mass of the segmented unit of blade 1 multiplied by the acceleration of gravity multiplied by the length of the segmented unit, and then divided by the bending section moment of the segmented unit section, and the section stress is obtained. When the impeller rotates, the bending stress on blade 1 changes with the clock position and repeats over and over again.

[0067] It can be seen from the above formulas (1) to (4) that the moments and forces at various parts of the blade 1 are not equal, so the bending degrees of different parts are different. By arranging a plurality of elastic cavities 12 in sections 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 various parts of the blade 1 and avoiding the breakage of the blade 1.

[0068] Figure 2 is a curve of the change of the external force load along the blade span direction in 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 root of the blade to the tip of the blade, so the interval between the partitions 11 can be increased successively from the root of the blade 1 to the tip of the blade 1, which saves costs, can well resist 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 arranged on the outer wall of the tower in the windward direction relative to the tip of the blade 1 passing across the tower of the wind turbine, or is arranged on the inner wall of the shell 10 where each section of the 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, which is arranged at the root of the blade 1, for adjusting the expansion pressure in each section of the elastic cavity 12 according to the bending amount of the blade 1.

[0070] Specifically, the bending distance sensor 13 installed on the tower wall cooperates 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 and passes the windward direction (windward side) of the tower wall, the potential induced by the sensor coil on the tower wall 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 a 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 12.

[0071] One of the distance measurement principles: using the principle of electromagnetic induction, the non-electrical quantity of distance measurement is converted into the change of self-inductance or mutual inductance of the electromagnetic coil. The windward surface of the metal tower (or tower frame) is a part of the eddy current sensor. The coil is placed in the blade 1. When the alternating high-frequency current is passed through the coil, an alternating magnetic flux φ will be caused. Due to the effect of the alternating magnetic flux φ, when the blade 1 rotates close to the windward surface of the tower, the coil faces the tower and generates an induced current on the metal surface and inside of the tower. The induced current is the eddy current, which is closed on the metal surface and inside of the tower. The metal conductor on the surface and inside of the tower is abstracted as a short-circuited coil. According to Lenz's law, the alternating magnetic flux φ1 generated by the eddy current will be opposite to the magnetic field generated by the coil in the blade 1, which reduces the inductance of the coil. The smaller the spacing δ, the greater the reduction of the coil inductance, that is, φ1 resists the change of φ. Due to the effect of the eddy current magnetic field, the equivalent impedance Z of the coil will change. The degree of change is related to the distance δ between the above two, and it is a single-valued function, Z=F(δ). The measuring circuit converts the change of impedance into the change of voltage, thereby achieving the purpose of converting the distance δ into electrical quantity.

[0072] The second distance measurement principle: a permanent magnetic component is embedded in the blade 1, and the N pole or S pole of the magnetic pole faces the tower, and an induction coil is set on the outer wall of the tower of the wind turbine bearing structure (it can be a diaphragm type, with a coil buried inside the diaphragm, and the diaphragm is attached to the tower wall). The coil is a mutual inductance object of the electromagnetic induction principle, and the magnitude of the coil induced potential is inversely proportional to the spacing (the spacing between the permanent magnetic pole and the tower). The proportional coefficient can be obtained using the experimental point method, from the minimum spacing (starting from contact) to the maximum spacing between the blade 1 and the tower wall when there is no wind, to obtain several values ​​of the induced potential, connect the test points to form a curve, and the slope of the curve is used as its proportional coefficient.

[0073] Figure 3is a schematic structural diagram of a fluid replenishing device according to an embodiment of the present invention. Figure 3 As shown, in some embodiments, the fluid replenishment device 14 includes: an air pump 141, an air supply pipeline 142, an outlet pressure flow transmitter 143, a drive motor 144, and an air source controller 145; one end of the air supply pipeline 142 is connected to the air pump 141, and the drive motor 144 is installed 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 flow of the outlet of the air supply 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 flow of the outlet of the air 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. The embodiment of the present invention can provide a suitable fluid to each section of the elastic cavity 12, so that the pressure generated from the inside to the outside of each section of the elastic cavity 12 is sufficient to resist the expansion pressure of the bending degree of each part of each blade 1.

[0074] Figure 7 is a schematic structural diagram of a wind power generation device with segmented resistance to blade bending according to an embodiment of the invention, such as Figure 7 As shown, in some embodiments, it also includes: a bending load sensor 15 arranged on the shell 10, used to measure the load of the blade 1; an air source controller 145 is used to judge whether to replenish fluid in each section of the elastic cavity 12 according to the load, the bending and the automatic control model stored in the adaptive regulator stored in the air source controller 145, and according to 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 section of the elastic cavity 12 is less than the pressure value that restores the bending of the blade 1 of the current section, the fluid replenishing device 14 is controlled to fill the fluid into each section of the elastic cavity 12 to automatically adjust the expansion pressure of each section of the elastic cavity 12 from the inside to the outside; wherein, in the automatic control model, each section of the elastic cavity 12 corresponds to a pressure value that restores the bending of the shell 10 of its corresponding section.

[0075] Specifically, in the automatic control model, each section of the elastic cavity 12 corresponds to a pressure value for restoring the bending amount of the shell 10 of its corresponding section. Different positions of the blade 1 shell 10 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 12 and its corresponding shell 10 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 10, and also avoid excessive expansion pressure that cannot play a role in resisting the bending of the shell 10.

[0076] In some embodiments, the automatic control model is obtained in the following manner: obtaining the load of the wind turbine from the bending load sensor 15 provided on the blade 1; obtaining the natural environment wind speed in which the wind turbine is located and the load of the wind turbine, and establishing a corresponding relationship between the natural environment wind speed and the load of the wind turbine and the bending amount respectively; obtaining the functional relationship between the expansion pressure values ​​of the elastic cavity 12 required to reduce or restore different bending amounts according to the corresponding relationship, and storing the functional relationship in the adaptive regulator as an automatic control model.

[0077] Specifically, in actual use, the wind speed in front of the wind turbine is taken as the reference wind speed. The aerodynamic bending moment at the root of blade 1 is synthesized by the bending moment in the swinging direction and the circumferential bending moment. The bending moment in the swinging direction is generated by the thrust, and the circumferential bending moment is caused by the circumferential force, that is, the driving moment divided by the number of blades 1. The cross section of blade 1 is a variable section, with hollow sections and solid sections. The airfoil section relies on finite element calculation to obtain the bending stress from the root to the tip of blade 1; the bending stress generated by gravity on the impeller blade 1 from the root to the tip is equal to the mass of the segmented unit of blade 1 multiplied by the acceleration of gravity multiplied by the length of the segmented unit, and then divided by the bending section moment of the segmented unit section to obtain the section stress. When the impeller rotates, the bending stress on blade 1 changes with the clock position and repeats over and over again.

[0078] After the bending stress is obtained, 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 by the general superposition method of 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 145. The distance sensor of blade 1 can be arranged in the windward direction of the tower relative to the tip of blade 1, or it can be set in the elastic cavity 12 set in sections in 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 are proportional 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 145. 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. Their difference is multiplied by a correction coefficient between 0 and 1. The correction coefficient 1 means that the bending deformation is completely restored, and the correction coefficient 0 means no restoration. As a control target, the elastic cavity 12 supports the blade 1 to resist bending, and tries to make the blade 1 close to the state before bending, but not absolutely close.

[0079] In this embodiment, the upwind airflow (upstream airflow of the wind turbine) passes through the blade 1 to do work. From formula (1) to formula (4), it can be seen that the torque formed 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 changes the pitch to change the wind turbine output, the corresponding reduction in power output and the bending condition of the blade 1 are measured by the bending load sensor 15 installed on the blade 1 and the sensor installed on the tower wall and the magnetic steel a on the tip of the blade 1 to establish a quantitative relationship between the wind turbine output and the bending degree. At the same time, air is supplied to the elastic cavity 12 in the shell 10 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 expansion pressure of the elastic cavity 12 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).

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

[0081] Specifically, after the blade 1 is subjected to airflow and various loads, the elastic cavity 12 establishes a new cavity structure inside the blade 1 with a pressure greater than the natural environment. The air pressure in 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 environment 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 formula (1) to formula (4), the function values ​​on the left side of the formula are proportional to the change of air flow density, and the density is inversely proportional to the temperature (that is, 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.

[0082] After the blade 1 is subjected to the airflow and various loads, the elastic cavity 12 establishes a new cavity structure inside the blade 1 with a pressure greater than the natural environment. The air 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 (Formula (5) calculates the total differential of the composite function with respect to (T, p)).

[0083] Similarly, after the blade 1 is subjected to the airflow and various loads, the elastic cavity 12 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 and the natural environment temperature, wind speed and local atmospheric pressure. In this embodiment, according to the gas state equation, the change of the airflow temperature in the wind farm produces a heating or cooling effect on the shell 10 of the blade 1, and the elastic cavity 12 also expands and contracts accordingly. Similarly, the atmospheric pressure of the natural environment in which the wind turbine is located will also produce different pressures on the elastic cavity 12, so in this embodiment, the air temperature and air pressure are used as auxiliary input parameters of the feedback control of the adaptive regulator to better control the expansion pressure in the elastic cavity 12. In this embodiment, after the blade 1 is subjected to the airflow and various loads, the fluid power device 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 and the natural environment temperature, wind speed and local atmospheric pressure.

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

[0085] Figure 6 Schematic diagram of a wind turbine blade structure with an air intake duct according to an embodiment of the present invention. Figure 6As shown, in some embodiments, for the convenience of management, the blade 1 further includes an air intake pipeline 16, on which a plurality of check valves 161a are provided, and the check valves 161a are respectively connected to the filling inlet 122 of the elastic cavity 12; or, the air intake pipeline 16 is provided with a plurality of electric control valves 161b, and the electric control valves 161b are respectively connected to the filling inlet 122 of the elastic cavity 12; the plurality of electric control valves 161b are electrically connected to the electric control valve 161b control bus, and the opening and closing of the electric control valves 161b are controlled by the electric control valve 161b control bus to replenish the fluid into the elastic cavity 12. When the electric control valve 161b is provided on the air intake pipeline 16, a plurality of electric control valves 161b are controlled by the electric control valve 161b control bus to replenish the fluid into the elastic cavity 12; each section of the elastic cavity 12 is also provided with an exhaust solenoid valve 123, and the opening and closing of each solenoid valve is respectively controlled by the exhaust solenoid valve 123 control bus. When the internal pressure value of a certain section of the elastic cavity 12 is greater than the pressure value required for the shell 10 to restore the bending amount, the fluid in the elastic cavity 12 can be discharged through the exhaust solenoid valve 123 to adjust the expansion pressure in each section of the elastic cavity 12 in real time.

[0086] In this embodiment, the opening and closing of several electrically controlled valves 161b can be uniformly controlled through the electrically controlled valve 161b control bus, and fluid can be individually injected into each section of the elastic cavity 12. The exhaust solenoid valve 123 can also be uniformly controlled to allow the fluid inside each section of the elastic cavity 12 to flow out, thereby individually and in real time controlling the expansion pressure of each elastic cavity 12 from the inside to the outside to better resist the bending degree of the blade 1. Since excessive or redundant expansion pressure can also cause fatigue loads on the shell 10 of the blade 1, such as during the windless season, windless period, and long-term shutdown and maintenance period of the wind farm, the exhaust solenoid valve 123 connected to the elastic cavity 12 is provided in this embodiment to maintain the required pressure of the elastic cavity 12 space.

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

[0088] The wind power generator of the embodiment of the present invention sets elastic cavities 12 in sections in the shell 10 of the blade 1, so that the inner surface of the shell 10 of the blade 1 is no longer affected by atmospheric pressure, or is approximately affected by atmospheric pressure. The inner surface of the shell 10 of the blade 1 can be supported according to the rigidity requirement. Since the inner surface has a nearly rigid surface support, the inner surface of the shell 10 will no longer have a large reciprocating bending deformation in two directions, especially preventing the outer surface of the shell 10 from bending, sinking or buckling toward the inner surface. In addition, a protective cover can also be set on the outside of the elastic cavity 12. The protective cover bulges after relying on sufficient gas in the elastic cavity 12 and its own rigid surface can resist the reaction force generated by external force, balance the pressure difference between the pressure surface and the suction surface of the blade 1, and avoid the tendency of the blade 1 to bulge or sink. That is, this balance prevents the deformation of the pressure surface and the suction surface, which is the potential contribution of the pressure energy or potential energy constructed by the sufficient gas in the elastic cavity 12. It is also called the internal support that can resist the bending of the blade 1 or the new structure that can resist the bending of the blade 1. Since the blades 1 used in the wind power generation device in this embodiment have the function of resisting bending, the service life of the wind power generation device can be increased.

[0089] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A wind turbine blade (1) having a segmented structure for resisting blade bending, characterized in that: The blade (1) comprises: a shell (10), a plurality of partitions (11) and a plurality of elastic cavities (12); The partitions (11) are arranged at intervals in the cavity formed by the shell (10); the elastic cavity (12) is arranged between any two partitions (11) and extends along the length direction of the blade (1); After expansion, each section of the elastic cavity (12) contacts the inner surface of the shell (10) and the partition (11), and each section of the elastic cavity (12) is provided with a pressure sensor (121) for measuring the pressure value of the elastic cavity (12) in real time.

2. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 1, characterized in that: The intervals between the partitions (11) increase gradually from the root of the blade (1) to the tip of the blade (1).

3. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 1 or 2, characterized in that: It also includes: a bending distance measuring sensor (13), which is arranged on the outer wall of the tower in the windward direction relative to the tip of the blade (1) passing across the tower of the wind turbine, and is used to measure the bending amount of the blade (1); The wind turbine blade (1) further comprises a fluid replenishing device (14), which is arranged at the root of the blade (1) and is used to adjust the capacity of the fluid in each section of the elastic cavity (12) according to the bending amount of the blade (1).

4. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 3, characterized in that: The fluid replenishment device (14) comprises: 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 installed 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 flow of the outlet of the air supply pipeline (142) to the air source controller (145); The gas source controller (145) is used to input a control signal to the driving motor (144) according to the pressure flow rate at the outlet of the gas supply pipeline (142); The driving motor (144) is used to control the air pump (141) to locally supply air to each section of the elastic cavity (12) through the air supply pipeline (142) according to the control signal.

5. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 4, characterized in that: Also includes: A bending load sensor (15) is arranged on the housing (10) and is used to measure the load of the blade (1); The air source controller (145) is used to determine whether to add fluid to each section of the elastic cavity according to the load amount, the bending amount and the automatic control model stored in the adaptive regulator stored in the air source controller (145), and according to the pressure value measured by the pressure sensor on each section of the elastic cavity; When the pressure value measured by the pressure sensor on each section of the elastic cavity (12) is less than the pressure value that restores the bending amount of the shell corresponding to the current section, the control fluid replenishment device (14) fills the fluid into each section of the elastic cavity (12) to automatically adjust the expansion pressure of each section of the elastic cavity (12) from the inside to the outside; wherein, in the automatic control model, each section of the elastic cavity (12) corresponds to a pressure value that restores the bending amount of the shell (10) of its corresponding section.

6. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 5, characterized in that: The automatic control model is obtained in the following way: Obtaining the load of the wind turbine from a bending load sensor (15) arranged on the blade (1); Acquire the natural environment wind speed of the wind turbine and the load of the wind turbine, and establish corresponding relationships between the natural environment wind speed and the load of 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.

7. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 5, characterized in that: Each section of the elastic cavity (12) is provided with a filling port (122), and the fluid includes gas or liquid; The air source controller (145) controls the air pump (141) to fill each section of the elastic cavity (12) with fluid 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 fill each section of the elastic cavity (12) with fluid through the filling inlet (122) according to the atmospheric pressure 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 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.

8. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 7, characterized in that: The blade (1) further comprises a plurality of air inlet pipes (16) which are arranged in a cavity formed by the shell (10) and extend in sequence along the blade root of the blade (1) towards the blade tip in the cavity; A check valve (161a) is provided on each of the air inlet pipes (16), and the check valve (161a) is connected to the filling inlet (122) of the elastic cavity (12) and is used to replenish the fluid in the elastic cavity (12); An exhaust solenoid valve (123) is also provided on each section of the elastic cavity (12), and the exhaust solenoid valve (123) is electrically connected to a control bus of the exhaust solenoid valve (123), and the opening and closing of each exhaust solenoid valve (123) is controlled by the control bus of the exhaust solenoid valve (123).

9. The wind turbine blade (1) with a segmented structure for resisting blade bending according to claim 7, characterized in that: The blade (1) further comprises an air intake pipeline (16), on which a plurality of electrically controlled valves (161b) are arranged, and the electrically controlled valves (161b) are respectively connected to the charging inlets (122) of the elastic cavity (12); The electrically controlled valve (161b) is electrically connected to a control bus of the electrically controlled valve (161b), and the opening and closing of the electrically controlled valve (161b) are controlled by the control bus of the electrically controlled valve (161b); An exhaust solenoid valve (123) is also provided on each section of the elastic cavity (12), and the opening and closing of each solenoid valve is controlled respectively through a control bus of the exhaust solenoid valve (123).

10. A wind power generation device (2) having a blade (1) that resists bending, characterized in that: The wind power generation device comprises a wind turbine blade (1) as claimed in any one of claims 1 to 9.

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