Wind turbine device for resisting bending of wind turbine blades through self-adaptive adjustment and control method

Abstract

The invention discloses a wind turbine device for resisting bending of blades of a wind turbine through self-adaptive adjustment and a control method. The wind turbine device comprises the blades, an air source, an air source controller, a bending distance measuring sensor and a self-adaptive adjuster arranged in the air source controller. Each blade comprises a shell, a plurality of partition plates and a plurality of elastic cavities, the partition plates are arranged in the shell at intervals and divide the shell into a plurality of closed cavities, and the elastic cavities are arranged in the closed cavities; a pressure sensor is arranged on the elastic cavity and is used for measuring a pressure value on the elastic cavity; the bending distance measuring sensor is arranged on a shell of the blade and used for measuring the bending amount of the blade. And the air source controller controls the air source to fill fluid into the elastic cavity according to a control model stored in the self-adaptive regulator so as to automatically regulate the expansion pressure of the elastic cavity from inside to outside. The expansion pressure of each elastic cavity from inside to outside can be adjusted in a self-adaptive mode, and the bending degree of all parts of the blade can be accurately resisted.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine blade shape control, and in particular to a wind turbine device and a control method for adaptively adjusting and resisting the bending of wind turbine blades. 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, CN114718802A, an improved method for the anti-buckling phenomenon of the blades of the horizontal axis wind turbines in service, discloses an improved method for the anti-buckling phenomenon of the blades of the horizontal axis wind turbines in service. The method includes the following steps: evaluating the buckling characteristics of the blades of the wind turbines 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 parts, and installing anti-buckling reinforcement structural components to achieve that the blades in service meet the anti-buckling performance requirements. By adopting 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 layer 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, CN114580247A, 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] In addition, in order to solve the problem of large vibration deformation of wind turbine blades, the current method also includes increasing 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 order of 100 meters, the clearance distance of the blade tip pre-bend will be as high as 4 meters, but this practice changes the aerodynamic characteristics of the blade to a certain extent, thereby reducing the power output of the wind turbine, seriously affecting the economic efficiency of wind power generation. In terms of operation strategy, the wind turbine blades are controlled by variable pitch to reduce wind loads. Although this practice 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 wind direction changes, 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 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 device and a control method for adaptively adjusting the resistance to bending of wind turbine blades, so as to solve the technical problem of blade bending and breaking due to excessive blade size in the prior art.

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

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

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

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

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

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

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

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

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

[0017] The 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;

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

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

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

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

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

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

[0024] Obtaining the bending amount of the blade from a bending distance measuring sensor arranged on the blade;

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

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

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

[0028] 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;

[0029] 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.

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

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

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

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

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

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

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

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

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the 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 It is a structural schematic diagram of a wind turbine device for adaptively adjusting and resisting bending of wind turbine blades provided by the present invention;

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

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

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

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

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

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

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

[0047] Fig. 9 The present invention provides a flow chart for obtaining an automatic control model. Description of the drawings:

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

[0050] 11. Shell; 12. Partition; 13. Closed cavity; 14. Air intake pipe; 141a. Check valve; 141b. Electric control valve; 15. Exhaust solenoid valve; 16. Image sensor; 17. Elastic cavity; 171. Pressure sensor; 172. Inflatable port;

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

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

[0053] a. Magnetic steel. DETAILED DESCRIPTION

[0054] The following will 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.

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

[0056] In this embodiment, in the automatic control model, each elastic cavity 17 corresponds to a pressure value for restoring the bending amount of the shell 11 of the corresponding section thereof. Different positions of the shell 11 of the blade 1 are subjected to different forces, resulting in different bending amounts, so that different expansion pressure values ​​are required to restore or reduce different bending amounts. Therefore, each section of the elastic cavity 17 and its corresponding shell 11 will have a series of pressure values. These pressure values ​​can restore different bending amounts, that is, provide a suitable pressure value to avoid excessive expansion pressure that further damages the shell 11 of the blade 1, and also avoid excessive expansion pressure that cannot play a role in resisting the bending of the shell 11.

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

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

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

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

[0061] In some embodiments, the wind turbine device may further include: a bending load sensor 4, which is disposed on the housing 11 of the blade 1 and is used to measure the load of the blade 1. The air source controller 20 is also used to control the air source 2 to fill the elastic cavity 17 with fluid according to the load and bending amount of the blade 1 and the automatic control model stored in the adaptive regulator to automatically adjust the expansion pressure of the elastic cavity 17 from the inside to the outside.

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

[0063] like Figure 2 As shown, in some embodiments, the load generated by the external force on the blade 1 gradually increases from the blade root to the blade tip, that is, the external force load is gradually increased along the span direction of the blade 1 except for the blade tip, so the lengths of the plurality of closed cavities 13 increase successively from the root of the blade 1 to the tip of the blade 1, and the automatic control model is a functional relationship between the expansion pressure values ​​of each elastic cavity required to reduce or restore different bending amounts; the numerical relationship means that each elastic cavity 17 corresponds to a set of pressure values ​​that restore or reduce the bending amount of the shell 11 where the corresponding closed cavity 13 is located, that is, in the automatic control model, each elastic cavity 17 Each elastic cavity 17 corresponds to a set of pressure values ​​for restoring the bending amount of the shell 11 of its corresponding section. Because different positions of the blade shell 11 are subjected to different forces and produce different bending amounts, different expansion pressure values ​​are required to restore or reduce different bending amounts. Therefore, each section of the elastic cavity 17 and the shell 11 where the corresponding closed cavity 13 is located will have a series of pressure values. These pressure values ​​can restore different bending amounts, that is, provide a suitable pressure value to avoid excessive expansion pressure that further damages the blade 1 shell 11, and also avoid excessive expansion pressure that cannot resist the bending of the shell 11.

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

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

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

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

[0068] Figure 6 is a schematic diagram of the internal structure of a wind turbine blade including an air intake duct according to an embodiment of the present invention. Figure 6 As shown, optionally, in order to facilitate unified management, the blade 1 can also be provided with an air intake pipeline 14, and a plurality of electrically controlled valves 141b are provided on the air intake pipeline 14, and the electrically controlled valves 141b are respectively connected to the air charging ports 172 of the elastic cavity 17, and each electrically controlled valve 141b is individually controlled through a control line of the electrically controlled valve 141b (e.g., an electrically controlled valve control bus) to replenish fluid into the elastic cavity 17. In the embodiment of the present invention, the opening and closing of a plurality of electrically controlled valves 141b can be uniformly controlled through the electrically controlled valve 141b control bus to individually control the pressure of each elastic cavity 17 from inside to outside.

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

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

[0071] Embodiment 2

[0072] Figure 8 Flow chart of a control method for adaptively adjusting the resistance to bending of wind turbine blades provided by the present invention. Figure 8 As shown, the control method is applicable to the wind turbine device described in the first embodiment, and comprises the following steps:

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

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

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

[0076] Specifically, the bending distance sensor 3 installed on the wall of the tower 9 cooperates with the magnet a on the tip of the blade 1 to measure the bending amount of the blade 1. When the tip of the blade 1 rotates and passes the windward direction (windward side) of the tower 9 wall, the potential induced by the sensor coil on the wall of the tower 9 is the largest when the distance is closest. A one-to-one correspondence is established between the induced potential and the distance between them, which serves as 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.

[0077] 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 9 (or tower frame) is a part of the eddy current sensor, and 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, when the blade 1 rotates close to the windward surface of the tower 9, the coil faces the tower 9 and generates an induced current on the metal surface and inside of the tower 9. This current is the eddy current, which is closed on the metal surface and inside of the tower 9. The metal conductor on the surface and inside of the tower 9 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 more the coil inductance decreases, 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.

[0078] The second distance measurement principle: embed a permanent magnetic component in the blade 1, and make the N pole or S pole of the magnetic pole face the tower 9, and set an induction coil on the outer wall of the tower 9 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 wall of the tower 9). The coil is the mutual inductance object of the electromagnetic induction principle. The magnitude of the coil induced potential is inversely proportional to the spacing (the spacing between the permanent magnetic pole and the tower 9), and the proportional coefficient is obtained. The test point method can be used to obtain several values ​​of the induced potential from the minimum spacing (starting from contact) to the maximum spacing between the blade 1 and the tower 9 wall when there is no wind, and the test points are connected to form a curve, and the slope of the curve is used as its proportional coefficient.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0093] C P The dimensionless power coefficient, ρ, is the air flow density.

[0094] 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 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.

[0095] After the bending stress is obtained, the bending deformation of blade 1 after being subjected to force is calculated. For several different loads, the bending moments can be superimposed, that is, the total bending deformation mentioned above is calculated using the general superposition method 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 by the air source controller 20 at any time. The distance sensor of blade 1 can be arranged in the windward direction of the tower 9 relative to the tip of blade 1, or it can be set in the elastic cavity 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 20. In addition, this embodiment can use the measurement data of the ranging sensor as the subtrahend of the subtraction operation, and the design value of the blade 1 before bending as the minuend. 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 supports the blade 1 to resist bending, and tries to make the blade 1 close to the state before bending, but not absolutely close.

[0096] In this embodiment, the upwind airflow (upstream airflow of the wind turbine) passes through the blade 1 to do work. It can be seen from equations (1) to (4) 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 of the wind turbine to change the output of the wind turbine, the corresponding reduction in power output and the bending condition of the blade 1 are measured by the bending load sensor installed on the blade 1 and the sensor installed on the wall of the tower 9 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 in the shell 11 of the blade 1 to establish an expansion pressure (with the help of a ranging sensor) that is greater than the natural atmospheric pressure and large enough to help the blade 1 material resist bending, so that the bending degree of the blade 1 is reduced or restored, and the corresponding elastic cavity expansion pressure is obtained. This pressure value set is stored in an adaptive anti-bending regulator as the basic basis for control and regulation (or control model, forming a control algorithm).

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

[0098] Specifically, after the blade 1 is subjected to airflow and various loads, the elastic cavity 17 establishes a new cavity structure inside the blade 1 with a pressure greater than the natural environment. The 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 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 the 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, while density is inversely proportional to temperature (the control law is obtained by differentiating the gas temperature on the left side of formula (5). In summary, the total differential of the composite function is obtained.

[0099] After the airflow and various loads on the outside of blade 1 act on it, the elastic cavity establishes a new cavity structure inside 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)).

[0100] Similarly, after the blade 1 is subjected to the airflow and various loads, the elastic cavity establishes a new cavity structure inside the blade 1 with a pressure greater than the natural environment. The pressure inside the new cavity structure can automatically adjust the outward expansion pressure in the cavity according to the power output of the wind turbine 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 11 of the blade 1, and the elastic cavity 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, 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. 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.

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

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

[0103] The above 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 device capable of adaptively adjusting the resistance to bending of a wind turbine blade (1), characterized in that: The wind turbine device comprises: a blade (1), an air source (2), an air source controller (20), a bending distance sensor (3), and an adaptive regulator arranged in the air source controller (20); The blade (1) comprises: a shell (11), a plurality of partitions (12) and a plurality of elastic cavities (17); the partitions (12) are arranged in the shell (11) at intervals to divide the shell (11) into a plurality of closed cavities (13); each closed cavity (13) is provided with one elastic cavity (17); each closed cavity (13) has an independent expansion pressure; each elastic cavity (17) is provided with a pressure sensor (171) for measuring the pressure value on the elastic cavity (17); The bending distance measuring sensor (3) is arranged on the outer wall of the tower in the windward direction relative to the tip of the blade (1) passing through the tower (9), and is used to measure the bending amount of the blade (1); The air source controller (20) is used to control the air source (2) to fill the elastic cavity (17) with fluid according to the bending amount and the automatic control model stored in the adaptive regulator, so as to independently adjust the expansion pressure of each elastic cavity (17) from the inside to the outside.

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

3. The wind turbine device according to claim 2, characterized in that: The lengths of the plurality of closed cavities (13) increase sequentially from the root of the blade (1) to the tip of the blade (1); The automatic control model is a functional relationship between the expansion pressure values ​​of each elastic cavity (17) required to reduce or restore different bending amounts; the functional relationship refers to a set of pressure values ​​corresponding to each elastic cavity (17) that restores or reduces the bending amount of the shell where the corresponding closed cavity is located.

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

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

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

7. A control method for adaptively adjusting the resistance to bending of a wind turbine blade (1), characterized in that: The control method is applicable to the wind turbine device according to any one of claims 1 to 6, and the control method is executed by an air source controller (20), and the control method comprises: Acquiring an automatic control model, and storing the automatic control model in the adaptive regulator; Acquiring the bending amount of the blade (1) from a bending distance measuring sensor (3) arranged on the blade (1); According to the bending amount and the automatic control model, the air source (2) is controlled to fill each elastic cavity (17) with fluid to adjust the expansion pressure of the elastic cavity (17) from the inside to the outside.

8. A control method for adaptively adjusting the resistance to bending of a wind turbine blade (1) according to claim 7, characterized in that: The acquisition of the automatic control model specifically includes: Obtaining the load of the wind turbine through a bending load sensor (4) arranged 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 corresponding relationships between the natural environment wind speed and the load of the wind turbine and the bending amount respectively; A functional relationship between the expansion pressure values ​​of the elastic cavity (17) required to reduce or restore different bending amounts is obtained according to the corresponding relationship, and the functional relationship is stored in the adaptive regulator as an automatic control model.

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

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

Images