Blade system of wind generating set

Abstract

The invention discloses a blade system of a wind generating set, and belongs to the field of wind power generation systems. A hydraulic system drives a coaxial gear rigidly connected with the root of a main blade to provide power for a gear pump, hydraulic oil flow and speed are controlled by a hydraulic control element, and the hydraulic oil penetrates through the center of a main shaft through a double-channel rotary joint and reaches a blade motor at the top end of the main blade through an oil way laid on the inner surface of the main blade; and the blade motor drives the secondary blade module to rotate to form closed-loop energy supply. At low wind speed, the secondary blade module and the main blade rotate in the same direction, so that the aerodynamic efficiency is enhanced; at high wind speed, the secondary blade module and the main blade rotate reversely, reverse lift force is generated, and the tip bending moment of the blade is reduced. The core of the invention lies in that pneumatic coupling and hydraulic supply technologies are combined, so that not only is the application range of equipment to wind speed change widened, but also the utilization rate of wind energy is obviously improved. Revolutionary progress is brought to the field of wind power generation, and wide application prospects and market potential are shown.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power generation, and particularly relates to a blade system of a wind turbine generator set. Background Art

[0002] Modern wind turbine generators capture wind energy through blades and convert it into mechanical energy, and finally drive a generator to generate electric energy. A wind turbine generally consists of components such as blades, a gearbox, a radiator, and a control box. As the core component for capturing wind energy, the performance of the wind turbine blades directly determines the efficiency and reliability of the unit.

[0003] The core design of existing wind turbine blades focuses on aerodynamic performance and structural strength. Some related designs of wind turbine blades include: the blades usually adopt a streamlined design imitating an aircraft wing, using Bernoulli's principle to form a lift difference on the blade surface to drive the blade to rotate; large blades generally use lightweight materials such as carbon fiber to reduce weight and enhance the bending resistance; the blade angle is adjusted by pitch control to adapt to different wind speeds.

[0004] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following defects in the background art:

[0005] Long blades are prone to breathing deformation (radial bending) and torsional deformation under strong winds, resulting in local stress concentration and accelerating the fatigue damage of the blade composite materials. To cope with strong winds, the pitch system needs to frequently adjust the blade angle to reduce the stress. Although it can avoid breakage, it directly leads to a decrease in the wind energy capture efficiency. Summary of the Invention

[0006] In order to solve the problems that long blades are prone to breakage under strong winds and the wind abandonment rate is relatively high, an embodiment of the present invention provides a blade system of a wind turbine generator set. The technical solution is as follows:

[0007] A blade system of a wind turbine generator set, characterized by comprising: a power mechanism, a hydraulic system, and a blade structure; the power mechanism, a coaxial gear rigidly connected to the main shaft; the hydraulic system includes: a power element, a control element, and an actuator; the blade structure, each main blade top is rigidly connected to the actuator of the hydraulic system, and the actuator is connected to the secondary blade module; the coaxial gear meshes with an external gear to drive the power element in the hydraulic system, and through the hydraulic system transmission, it reaches the actuator of the hydraulic system to drive the secondary blade module.

[0008] Further, the main blade has a first blade length L1, and the secondary blade module has a second blade length L2, wherein the second blade length L2 is less than the first blade length L1.

[0009] Further, the number of blades of the secondary blade module is variable, including: a two-blade type, that is, the secondary blade module includes two secondary blades, and each secondary blade meets the limitation on the length L2 of the secondary blade in claim 2; a three-blade type, that is, the secondary blade module includes three secondary blades, and each secondary blade also meets the limitation on the length L2 of the secondary blade in claim 2.

[0010] Further, the actuator of the hydraulic system performs a rotational motion; the control element of the hydraulic system can control the rotational direction of the actuator of the hydraulic system.

[0011] At low wind speeds, the mechanical drive device drives the secondary blade module to rotate in the same direction as the main blade; at high wind speeds, the mechanical drive device drives the secondary blade module to rotate in the opposite direction to the main blade.

[0012] Further, it also includes a dual-path rotary joint arranged at one end of the main shaft close to the gearbox. The hydraulic oil passes through the center of the main shaft through the dual-path rotary joint and reaches the actuator of the hydraulic system at the top of the main blade through the inner surface of the main blade.

[0013] Further, the power element, the control element, and the actuator can be respectively selected as: a gear pump, a three-position four-way proportional valve, and a vane motor; for the gear pump, its oil inlet is connected to the hydraulic return oil circuit, and the gear pump obtains power through an external gear meshing with a coaxial gear rigidly connected to the root of the main blade; for the three-position four-way reversing proportional valve, its oil inlet P is connected to the oil outlet of the gear pump through a hydraulic pipeline; for the vane motor, its first working oil port A and second working oil port B are respectively connected to the working oil ports A and B of the three-position four-way reversing proportional valve correspondingly.

[0014] Further, the three-position four-way proportional valve is configured as: when in the left position, it leads the pressure oil into the A oil port of the vane motor and returns the oil from the B oil port, driving the vane motor to rotate forward; when in the right position, it leads the pressure oil into the B oil port of the vane motor and returns the oil from the A oil port, driving the vane motor to rotate backward; when in the middle position, it cuts off the oil circuit between the gear pump and the vane motor and connects the oil ports A and B of the motor to the fuel tank.

[0015] Further, the hydraulic system also includes: a hose, the oil inlet of the hose is connected to the gear pump; a check valve, the oil inlet of the check valve is connected to the oil outlet of the hose; a relief valve, the oil inlet of the relief valve is connected to the T port of the three-position four-way proportional valve; a filter, arranged in the return oil circuit, the oil inlet of the filter is connected to the oil inlet of the gear pump; a cooler, arranged in the return oil circuit, the oil inlet of the cooler is connected to the oil outlet of the filter; an energy storage module, the oil inlet of the energy storage module is connected to the oil outlet of the relief valve.

[0016] Furthermore, the energy storage module is suitable for connecting auxiliary components and serves as the hydraulic oil source of the hydraulic system.

[0017] Compared with the prior art, the beneficial effects of the present application are as follows:

[0018] When operating at low wind speeds, the secondary blade module rotates in the same direction as the main blade, generating additional lift. The tip linear velocity of the secondary blade module is superimposed on the rotational speed of the main blade, resulting in aerodynamic gain. The secondary blade module can utilize lower wind conditions, significantly increasing the lower limit of the wind speed it can withstand. When operating at high wind speeds, the secondary blade module rotates in the opposite direction to the main blade. When the secondary blade module rotates in reverse, it generates an aerodynamic force opposite to the lift direction of the main blade, reducing the bending moment and dynamic load in the tip region of the blade, enabling the wind turbine to withstand a greater load, effectively increasing the upper limit of the wind speed it can withstand, and improving the wind energy utilization rate. The rotation of the main blade and the secondary blade module complements each other, maximizing energy collection.

[0019] The curtailment rate of the wind turbine decreases from the traditional scheme, the annual power generation increases, the fatigue life of the blade is extended, the ultimate load-bearing wind speed is increased, showing significant technological progress. It breaks through the shackles of the traditional technology of "load reduction necessarily reduces efficiency". Through the innovative non-driven dual-mode collaborative design, while ensuring the safety of the blade, the power generation benefit is maximized, providing key technical support for the large-scale application of ultra-long blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the blade system of the wind turbine generator set of the present invention;

[0021] Figure 2 It is an assembly schematic diagram of the wind turbine generator set of the present invention;

[0022] Figure 3 It is a schematic cross-sectional view of the single-blade structure of the present invention;

[0023] Figure 4 It is a partially enlarged schematic diagram of the wind turbine generator set of the present invention;

[0024] Figure 5 It is a schematic diagram of the modular layout of the hydraulic system components of the present invention;

[0025] Figure 6 It is a schematic diagram of the hydraulic system principle of the present invention;

[0026] Reference Signs:

[0027] 1. Main blade; 2. Secondary blade module; 3. Power mechanism; 31. Coaxial gear; 32. Outer gear; 4. Hydraulic system; 41. Gear pump (power element); 42. Rubber hose; 43. Check valve; 44. Three-position four-way proportional valve (control element); 45. Relief valve; 46. Filter; 47. Cooler; 48. Accumulator module; 49. Double-path rotary joint; 410. Vane motor (actuating element); 411. Oil circuit; 5. Main shaft; 6. Gearbox; 7. Generator; 8. Radiator; 9. Control box. Detailed implementation manners

[0028] Next, in combination with the detailed implementation manners, the present application will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0029] In the description of the present application, it should be noted that for the orientation terms, if there are terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation and position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific protection scope of the present application.

[0030] It should be known that the existing generator blade design adopts the bionic design concept, draws on the streamlined structure of the aircraft wing, and forms a pressure difference on the blade surface based on the Bernoulli principle, thereby generating lift to drive the blade to rotate. In a typical design, the blade adopts an airfoil combination with different thicknesses along the span direction, and by optimizing the chord length and twist angle distribution, it is ensured that a high aerodynamic efficiency can be achieved under different wind speeds; to meet the lightweight and high-strength requirements of large blades, the existing technology generally uses carbon fiber reinforced composite materials as the main structural material; when the wind speed is too high, the existing technology realizes the dynamic adjustment of the blade angle through the pitch system to adapt to different wind speed conditions.

[0031] The embodiment cleverly integrates the design of the secondary blade module 2 at the top of the main blade 1 to create an innovative blade structure scheme. The distributed load reconstruction method is adopted to perform secondary distribution of the aerodynamic load in the tip region to achieve a leap in the mechanical performance of the generator blade system.

[0032] For better understanding, it is further illustrated by formulas:

[0033] Long blades are subjected to a huge bending moment M under strong winds, which can easily lead to material fatigue or failure under ultimate loads. F is the aerodynamic load, L is the blade length, F c is the centrifugal force, m is the blade mass, and ω is the blade angular velocity.

[0034] M = F·L / 2

[0035] F c = mω 2

[0036] The aerodynamic bending moment M borne by the long blade at wind speed v min , ρ is the air density, C L is the blade lift coefficient, A is the equivalent aerodynamic area of the blade (m 2 ), c(r) is the chord length distribution, R is the blade radius (m), and the proportionality coefficient K.

[0037]

[0038]

[0039]

[0040]

[0041] The bending moment has a linear relationship with the blade length, the equivalent aerodynamic area has a linear relationship with the blade length, and the average chord length has a linear relationship with the blade length. Then the load increases with R 3 grows. Currently, in order to prevent the blades of wind turbines from bearing excessive pressure caused by too high wind speed, which may lead to blade damage, pitch control is adopted, sacrificing the wind capture efficiency and reducing the power generation efficiency. In order to suppress the rapid increase of the load with the cube of the blade length, this patent proposes a blade structure for a wind power generation set. Compared with the blade design of the original power generation set, we can adopt the strategy of shortening the original blade length and adding a secondary blade module 2 at its top. By using the distributed load reconstruction method, the load is effectively reduced while the wind energy utilization rate is improved.

[0042] This application provides a blade system for a wind power generation set. One preferred embodiment includes a power mechanism 3, as Figure 4 shown, a hydraulic system 4, as Figure 2 shown, and the blade structure includes a main blade 1 and a secondary blade module 2, as Figure 1As shown, the power mechanism 3 includes a coaxial gear 31 rigidly connected to the main shaft 5; the hydraulic system includes a power element 41, a control element 44, and an actuator 410; for the blade structure, the top of each main blade 1 is rigidly connected to the actuator 410 of the hydraulic system, and the actuator 410 is connected to the secondary blade module 2; the coaxial gear 31 meshes with the external gear 32 to drive the power element 41 in the hydraulic system, and through the transmission of the hydraulic system 4, it reaches the actuator 410 of the hydraulic system 4 to drive the secondary blade module 2 to rotate.

[0043] In this embodiment, the main blade has a first blade length L1, and the secondary blade module has a second blade length L2, where the second blade length L2 is less than the first blade length L1.

[0044] The number of blades of the secondary blade module 2 is variable, including: two-blade type, that is, the secondary blade module includes two secondary blades; three-blade type, that is, the secondary blade module includes three secondary blades. The two-blade fan has fewer blades, less material consumption and lower overall weight, lower air resistance during high-speed rotation, smaller moment of inertia, and is more flexible in acceleration and deceleration. Under the same conditions, the two-blade length can be longer than that of the three-blade, with a larger wind-catching area and less interference between blades; the three-blade fan has more blades, more concentrated thrust pulses, significantly reduced vibration and noise, can generate greater thrust at low speeds, has a more uniform aerodynamic force distribution, reduces mechanical vibration, and extends the life of the engine and structure.

[0045] In this embodiment, the actuator 410 of the hydraulic system 4 performs a rotational motion; the control element 44 of the hydraulic system can control the rotational direction of the actuator 410 of the hydraulic system. At low wind speeds, the secondary blade module 2 rotates in the same direction as the main blade 1 to enhance the aerodynamic efficiency; at high wind speeds, the secondary blade module 2 rotates in the opposite direction to the main blade 1 to generate reverse lift, reduce the blade tip bending moment, and significantly improve the utilization rate of wind energy.

[0046] In this embodiment, it further includes a two-way rotary joint 49 provided at one end of the main shaft 5 close to the gearbox 6. The hydraulic oil passes through the main shaft center through the two-way rotary joint 49 and reaches the actuator 410 of the hydraulic system at the top of the main blade 1 through the inner surface of the main blade 1. The two-way rotary joint 49 connects the static system to input the hydraulic system 4 into the dynamically rotating main shaft 5, and simultaneously realizes the input and output of the hydraulic oil, playing a key role in transitional connection and sealing in the main shaft 5, ensuring the stable transmission of the hydraulic oil during rotation.

[0047] In this embodiment: The gear pump 41 is the power element of the hydraulic system 4, the three-position four-way proportional valve 44 is the control element of the hydraulic system 4, and the vane motor 410 is the actuator of the hydraulic system 4; For the gear pump 41, its inlet is connected to the hydraulic return oil circuit, and the gear pump 41 obtains power through the external gear 32 meshed with the coaxial gear 31 rigidly connected to the root of the main vane 1; For the three-position four-way reversing proportional valve 44, its inlet port P is connected to the outlet port of the gear pump through a hydraulic pipeline; For the vane motor 410, its first working oil port A and second working oil port B are respectively connected to the working oil ports A and B of the three-position four-way reversing proportional valve 44 through a double-path adapter 49.

[0048] In this embodiment, the three-position four-way proportional valve 44 is configured as follows: When in the left position, pressure oil is introduced into the A oil port of the vane motor and the B oil port returns oil, driving the vane motor 410 to rotate forward; When in the right position, pressure oil is introduced into the B oil port of the vane motor and the A oil port returns oil, driving the vane motor 410 to rotate backward; When in the middle position, the oil circuit between the gear pump 41 and the vane motor 410 is cut off and the motor oil ports A and B are connected.

[0049] The hydraulic system 4 further includes:

[0050] A rubber hose 42, the inlet of the rubber hose is connected to the gear pump, which can effectively absorb vibration, reduce noise, and improve the overall performance of the system and the comfort of the working environment;

[0051] A check valve 43, the inlet of the check valve is connected to the outlet of the rubber hose, which can prevent the oil from flowing back and maintain the pressure and flow stability of the system;

[0052] A relief valve 45, the inlet of the relief valve is connected to the T port of the three-position four-way proportional valve, which is used for system pressure limitation and opens for unloading protection when overpressure occurs;

[0053] A filter 46, which is arranged in the return oil circuit, the inlet of the filter is connected to the inlet of the gear pump, which can filter oil particles and protect the valve group and the vane motor 410;

[0054] A cooler 47, which is arranged in the return oil circuit, the inlet of the cooler is connected to the outlet of the filter, which can maintain the oil temperature;

[0055] An accumulator module 48, the inlet of the accumulator module 48 is connected to the outlet of the relief valve 45, the accumulator module 48 is suitable for connecting to the auxiliary elements of the hydraulic system 4, the accumulator module 48 is suitable for being used as the hydraulic oil source of the hydraulic system 4, which has a buffer for pressure fluctuations and provides instantaneous flow compensation to solve the problem that the centrifugal force causes insufficient or uneven pressure in the hydraulic oil pipe.

[0056] The following are the relevant calculation formulas:

[0057] Power loss ΔP caused by shortening the blade loss , P 0 Rated power of the original blade (P 0 ∝R 2 v 3 ), R′ is the length of the shortened blade (R′ = kR, j < 1).

[0058]

[0059] Reverse torque T generated by the rotation of a single secondary blade module 2 fan , v rel Relative wind speed caused by the rotation of the main blade 1, ω main is the angular velocity of the main blade 1, C T Torque coefficient of the secondary blade module 2, A fan Swept area of the secondary blade module 2, r is the radius of the secondary blade module 2.

[0060] v rel = ω main R′

[0061]

[0062] Reduction in the root bending moment of the main blade 1, ΔM, n is the number of secondary blade modules. ΔM = nT fan R′

[0063] Balanced relationship between the power generation of the secondary blade module 2 and the power loss of the main blade 1, C P,fan Wind energy utilization rate of the secondary blade module, A original A shortened Swept area of the original blade and the shortened blade (m 2 )

[0064]

[0065] Linear velocity of the revolution of the main blade 1:

[0066] v tip = ω main R′

[0067] Tip speed ratio of the secondary blade module 2:

[0068]

[0069] Self-rotation power of the secondary blade module 2:

[0070] P fan = T fan ω fan η

[0071] Additional lift L when the secondary blade module 2 rotates forwardadd , the lift force L is canceled out when rotating in the reverse direction sub , C L,正 , C L,反 Positive / negative rotation lift coefficient

[0072]

[0073]

[0074] The transmission ratio i, Z of the coaxial gear 31 and the external gear 32 big Coaxial gear 31, Z small External gear 32. The transmission ratio determines the rotational speed of the external gear 32 relative to the coaxial gear 31.

[0075]

[0076] When operating at low wind speeds, the secondary blade module 2 rotates in the same direction as the main blade 1, generating additional lift. The tip linear velocity of the secondary blade module 2 is superimposed on the rotational speed of the main blade 1, generating aerodynamic gain. The secondary blade module 2 can utilize lower wind conditions, significantly increasing the lower limit of the wind speed it can withstand; when operating at high wind speeds, the secondary blade module 2 rotates in the opposite direction to the main blade 1. When the secondary blade module 2 rotates in the reverse direction, it generates an aerodynamic force opposite to the lift direction of the main blade 1, reducing the bending moment and dynamic load in the tip region of the blade, enabling the wind turbine to withstand a greater load, effectively increasing the upper limit of the wind speed it can withstand, and increasing the wind energy utilization rate. The rotation of the main blade 1 and the secondary blade module 2 complements each other to maximize energy collection.

[0077] Those of ordinary skill in the art can understand that the above are only preferred examples of the invention and are not used to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, for those skilled in the art, they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, etc. made within the spirit and principle of the invention shall be included within the protection scope of the invention.

Claims

1. A blade system of a wind turbine generator set, characterized in that: include: Power mechanism, hydraulic system, blade structure; The power mechanism is a coaxial gear rigidly connected to the main shaft; the hydraulic system includes: a power element, a control element and an actuator; the blade structure, each main blade top is rigidly connected to the actuator of the hydraulic system, and the actuator is connected to the secondary blade module; The coaxial gear meshes with the external gear to drive the power element in the hydraulic system, which is transmitted through the hydraulic system to the actuator of the hydraulic system to drive the secondary blade module.

2. The wind turbine blade system according to claim 1, characterized in that: The main blade has a first blade length L1, and the secondary blade module has a second blade length L2, wherein the second blade length L2 is smaller than the first blade length L1.

3. The wind turbine blade system according to claim 1 or 2, characterized in that: The number of blades of the secondary blade module is variable, including: Two-blade type, that is, the secondary blade module includes two secondary blades, each of which complies with the limitation on the secondary blade length L2 in claim 2; The three-blade type means that the secondary blade module includes three secondary blades, and each secondary blade also complies with the limitation on the secondary blade length L2 in claim 2.

4. The wind turbine blade system according to claim 1, characterized in that: The actuator of the hydraulic system performs rotational motion; the control element of the hydraulic system can control the rotation direction of the actuator of the hydraulic system; At low wind speeds, the actuator of the hydraulic system drives the secondary blade module to rotate in the same direction as the main blade; At high wind speeds, the actuators of the hydraulic system drive the secondary blade modules to rotate in the opposite direction to the main blades.

5. The wind turbine blade system according to claim 1, characterized in that: It also includes a double-channel rotary joint arranged at one end of the main shaft near the gearbox. The hydraulic oil passes through the double-channel rotary joint from the center of the main shaft, through the inner surface of the main blade to the actuator of the hydraulic system at the top of the main blade.

6. The wind turbine blade system according to claim 1, characterized in that: The power element, control element and actuator are selected from: gear pump, three-position four-way proportional valve and vane motor respectively; a gear pump, the oil inlet of which is connected to the hydraulic return oil circuit, the gear pump obtaining power through an external gear meshing with a coaxial gear rigidly connected to the root of the main blade; A three-position four-way proportional valve, whose oil inlet P is connected to the oil outlet of the gear pump through a hydraulic pipeline; The first working oil port A and the second working oil port B of the vane motor are respectively connected to the working oil ports A and B of the three-position four-way reversing proportional valve.

7. The wind turbine blade system according to claim 5, characterized in that: The three-position four-way proportional valve is configured as follows: When in the left position, the pressure oil is introduced into the A port of the vane motor and the oil is returned to the B port, driving the vane motor to rotate forward; When in the right position, the pressure oil is introduced into the B port of the vane motor and the oil is returned to the A port, driving the vane motor to rotate in the reverse direction; When in the middle position, the oil path between the gear pump and the vane motor is cut off and the motor oil ports A and B are connected.

8. The wind turbine blade system according to claim 1, characterized in that: The hydraulic system also includes A hose, wherein the oil inlet of the hose is connected to the gear pump; A one-way valve, the oil inlet of the one-way valve is connected to the oil outlet of the hose; A relief valve, the oil inlet of which is connected to the T port of a three-position four-way proportional valve; A filter is arranged in the oil return line, and the oil inlet of the filter is connected to the oil inlet of the gear pump; A cooler is arranged in the oil return circuit, and the oil inlet of the cooler is connected to the oil outlet of the filter; An energy storage module, wherein the oil inlet of the energy storage module is connected to the oil outlet of the overflow valve.

9. The wind turbine blade system according to claim 8, characterized in that: The energy storage module is suitable for auxiliary component connection, and the energy storage module is suitable for serving as a hydraulic oil source for the hydraulic system.

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