A wind turbine system with one tower and three wind blades and a method for operating the same

Abstract

This invention relates to the field of wind turbine technology, and discloses a single-tower, three-blade wind turbine system and its operation control method, comprising: a tower; a main wind turbine installed at the top of the tower; and two secondary wind turbines located below the main wind turbine, with the two secondary wind turbines respectively mounted on the left and right sides of the tower via supports. This invention adds two symmetrically distributed secondary wind turbines to the traditional single main wind turbine. The main wind turbine captures high-altitude wind energy, while the secondary wind turbines capture mid- and low-altitude wind energy. The main and secondary wind turbine blades rotate independently in separate planes, fully utilizing wind energy at different altitudes and in different directions. Compared to traditional single-blade wind turbines, power generation is significantly increased, and wind energy utilization efficiency is greatly optimized. Utilizing the weight of the secondary wind turbines and the symmetrical layout effectively lowers the overall center of gravity of the tower, reducing tower sway and fatigue damage under complex weather conditions such as strong winds and turbulence, thus improving the operational stability and service life of the wind turbine.

Description

Technical Field

[0001] This invention relates to the field of wind turbine technology, and in particular to a single-tower, three-blade wind turbine system and its operation control method. Background Technology

[0002] The existing wind turbines have a relatively simple structural design, generally adopting the "one tower, one set of blades" model, in which there are usually three blades, which are set at the top of the tower to drive the generator to generate electricity by capturing wind energy. This structure has become mature after long-term application, but there are still many shortcomings in practical applications.

[0003] On the one hand, if it is necessary to increase the total power generation of a wind farm, the conventional solution of existing technology is to add independent wind turbines, that is, to increase the number of towers, blades, generators and supporting auxiliary facilities. This approach not only requires a large investment in equipment procurement costs, but also requires more land resources. At the same time, the construction and operation and maintenance costs of the new equipment will also increase significantly, resulting in a lower return on investment for the wind farm, which does not meet the core requirement of reducing the cost per kilowatt-hour in the era of grid parity. Moreover, the multi-tower layout will increase the complexity of wind farm planning and management, and it is difficult to promote its application, especially in areas with scarce land resources.

[0004] On the other hand, the industry has tried to increase power generation by increasing the number of blades on the same tower, such as single-blade, double-blade, and five-blade designs. However, all of these designs have insurmountable technical defects: single-blade designs have large vibration amplitudes, and the main bearing is subjected to periodic impacts, requiring additional structural weight to offset the swaying, which violates the principle of lightweighting; double-blade designs have drastic changes in the center of gravity, which can easily cause low-frequency resonance and accelerate fatigue damage to the tower and bearings; and designs with five or more blades will lead to severe airflow interference between blades, with the wake of the previous blade disturbing the airflow environment of the next blade. The increase in power generation is limited, while the costs of materials, transportation, and installation increase significantly, resulting in a significant increase in the total life cycle cost and making it difficult to achieve large-scale application.

[0005] In addition, the blades of existing wind turbines are all concentrated at the top of the tower, which makes the overall center of gravity of the tower relatively high. Under complex weather conditions such as strong winds and turbulence, the stability of the tower is poor, and it is prone to swaying, fatigue damage and other problems, which affect the service life and operational safety of the equipment. If stability is improved by simply increasing the thickness of the tower wall, it will further increase the manufacturing cost and construction difficulty, creating a vicious cycle.

[0006] Therefore, how to design a wind turbine with a reasonable structure and convenient implementation that can effectively increase power generation, reduce equipment investment and operation and maintenance costs, enhance tower operation stability, and overcome the above-mentioned defects of existing technologies has become an urgent technical problem to be solved in the current wind power generation field. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a single-tower, three-blade wind turbine system to solve the problems in the prior art that make it difficult to balance the increase in wind turbine power generation and cost control, that multiple blades are prone to interference and imbalance of the center of gravity, and that the tower is not stable enough.

[0008] Another technical problem to be solved by the present invention is to provide an operation control method for a single-tower, three-blade wind turbine system to improve the stability of the secondary wind turbine in complex wake fields.

[0009] To achieve the above objectives, this application provides a single-tower, three-blade wind turbine generator system, comprising: Tower; The main fan is installed at the top of the tower; Two secondary fans are located below the main fan, and the two secondary fans are respectively installed on the radial sides of the tower via brackets; The rotation plane of the main blade in the main fan is parallel to and offset from the rotation plane of the secondary blade in the secondary fan, so that the main blade and the secondary blade do not interfere with each other when they rotate.

[0010] The main wind turbine blade is located in front of the secondary wind turbine blade.

[0011] The main sweep circle of the main blade and the secondary sweep circle of the secondary blade partially overlap on the frontal projection plane.

[0012] The secondary fan is located within 1 / 2 to 5 / 6 of the total height of the tower.

[0013] The secondary fan is located at 2 / 3 of the total height of the tower.

[0014] The line connecting the centers of the two secondary fans is perpendicular to the central axis of the tower.

[0015] The diameter of the secondary fan blades in the secondary fan is 1 / 3 of the diameter of the main fan blades in the main fan.

[0016] The support includes two symmetrically arranged cantilever frames. One end of the cantilever frame is fixed with an arc-shaped connecting part adapted to the outer wall of the tower. The end of the arc-shaped connecting part is fixed with an ear plate with a through hole. The two cantilever frames are tightly fixed to the tower by the ear plate and bolts. The other end of the cantilever frame is provided with an installation platform for installing the secondary fan.

[0017] The distance between the center of the secondary wind turbine and the outer wall of the tower is greater than the radius of the secondary wind turbine's sweeping circle.

[0018] A method for operating and controlling a single-tower, three-rotor wind turbine system, applied to the aforementioned single-tower, three-rotor wind turbine system, includes the following steps: S1. Collect the bending moment at the root of the secondary fan blades, the blade azimuth angle, and the vibration signal of the support frame. S2. Convert the torque in the rotating coordinate system into the overturning torque and yaw torque in the stationary coordinate system through coordinate transformation; S3. Based on torque signal and wake model, predict the entry / exit of blades into / out of the main wind turbine wake zone and output independent pitch compensation command in advance. S4. The compensation command is superimposed on the reference pitch command to drive the high dynamic servo mechanism to perform pitch control, smoothing power fluctuations, reducing impact loads, and ensuring stable operation of the unit.

[0019] Compared with the prior art, the above-conceptual technical solution conceived in this application has the following beneficial effects: 1. Based on the traditional single main wind turbine, this invention adds two symmetrically distributed secondary wind turbines. The main wind turbine captures high-altitude wind energy, while the secondary wind turbines capture mid- and low-altitude wind energy. The main and secondary wind turbine blades rotate independently in different planes, which can make full use of wind energy at different heights and in different directions. Compared with the traditional single-blade wind turbine, the power generation can be significantly improved, and the wind energy utilization efficiency is greatly optimized, which meets the needs of the wind power industry for high-efficiency development.

[0020] 2. Existing wind turbine blades are concentrated at the top of the tower, resulting in a high center of gravity and poor stability. This invention symmetrically positions two secondary blades in the middle of the tower. By utilizing the weight of the secondary blades and the symmetrical layout, the overall center of gravity of the tower is effectively lowered, reducing tower swaying and fatigue damage under complex weather conditions such as strong winds and turbulence, thereby improving the operational stability and service life of the wind turbine. 3. This invention eliminates the need for additional independent towers and supporting auxiliary facilities. The two secondary wind turbines can be directly installed on the existing towers, sharing the existing generator auxiliary systems, operation and maintenance facilities, grid connection equipment, etc., which significantly reduces the costs of equipment procurement, construction and installation, land occupation, and subsequent operation and maintenance. At the same time, the secondary wind turbine blades are smaller in size, resulting in lower material and manufacturing costs. Compared with the solution of adding independent wind turbines, the cost advantage is extremely obvious, which can effectively improve the return on investment of wind farms and meet the industry needs of the grid parity era.

[0021] 4. This invention solves the problem of multi-blade interference by using a planar layout. By using small-sized secondary blades and symmetrical arrangement, it avoids the defects caused by the increase in the number of blades, such as airflow interference, soaring costs, and increased vibration. Compared with existing single-blade, double-blade, and five-blade designs, the structure is more reasonable, the operation is more stable, and the economy is better.

[0022] 5. By combining the corresponding control methods, pitch trend commands can be generated in advance before the secondary wind turbine enters or exits the wake boundary. With the high dynamic servo drive, the end-to-end delay of the control is compressed to within milliseconds. This not only smooths out the power fluctuations caused by sudden changes in wind speed and improves the quality of grid-connected power, but also avoids the instantaneous damage of load impact peaks to the mechanical transmission chain, thus improving the stability of the secondary wind turbine in complex wake fields. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the main structure of the present invention.

[0025] Figure 2 This is a side view of the structure of the present invention.

[0026] Figure 3 This is a schematic diagram of the front view of the bracket in this invention.

[0027] Figure 4 This is a top view of the support structure in this invention.

[0028] Figure 5 This is a schematic diagram of the primary sweep circle and the secondary sweep circle in this invention.

[0029] Figure label: Tower 10, main fan 20, main blade 21, main swept circle 22, support 30, cantilever 31, arc-shaped connection 32, mounting platform 33, ear plate 34, through hole 35, secondary fan 40, secondary blade 41, secondary swept circle 42. Detailed Implementation

[0030] To more clearly illustrate the purpose, technical solution, and beneficial effects of this application, a further detailed description of this application is provided below in conjunction with illustrations and specific embodiments. It should be specifically noted that the specific embodiments described below are only for illustrating the technical content of this application and do not constitute a limitation on the scope of protection of this application.

[0031] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0032] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection via an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Example 1: See Figure 1 , 2 This invention provides a single-tower, three-blade wind turbine generator system, comprising: Tower 10; The main wind turbine 20 is installed on top of the tower 10 to capture high-altitude wind energy and drive the generator to generate electricity; Secondary fans 40 are located below the main fans 20, and the two secondary fans 40 are installed on the left and right sides of the tower 10 respectively via brackets 30.

[0034] This invention adds two symmetrically distributed secondary wind turbines 40 to the traditional single main wind turbine 20. The main wind turbine 20 captures high-altitude wind energy, while the secondary wind turbines 40 capture mid- and low-altitude wind energy. The main and secondary wind turbine blades rotate independently in separate planes, making full use of wind energy at different altitudes and in different directions. Compared with traditional single-blade wind turbines, power generation can be significantly increased, and wind energy utilization efficiency is greatly optimized, meeting the high-efficiency development needs of the wind power industry. Existing wind turbine blades are concentrated at the top of the tower, resulting in a high center of gravity and poor stability. This invention symmetrically positions the two secondary wind turbine blades in the middle of the tower. By utilizing the weight of the secondary wind turbines 40 and the symmetrical layout, the overall center of gravity of the tower is effectively lowered, reducing tower swaying and fatigue damage under complex weather conditions such as strong winds and turbulence, thus improving the operational stability and service life of the wind turbine. In this embodiment, the main fan blade 21 of the main fan 20 has three blades, and the secondary fan blade 41 of the secondary fan 40 also has three blades.

[0035] Further, see Figure 2The main blade 21 of the main fan 20 and the secondary blades 41 of the secondary fan 40 are respectively arranged in two parallel and staggered planes. That is, the plane where the main blade 21 is located is parallel to the plane where the two secondary blades 41 are located, and there is a staggered distance between them. Although there is some projection intersection between the main blade 21 and the secondary blades 41, they do not interfere with each other during rotation because they are not on the same plane. They can rotate independently and capture wind energy at different heights and in different directions. The multi-blade interference problem is solved by the split-plane layout. The small-sized secondary blades and symmetrical arrangement avoid the defects of airflow interference, cost increase, and increased vibration caused by the increase in the number of blades. Compared with the existing single-blade, double-blade, and five-blade designs, the structure is more reasonable, the operation is more stable, and the economy is better.

[0036] In this embodiment, see Figure 2 The main wind turbine blade 21 is located in front of the secondary wind turbine blade 41; the main sweeping circle 22 of the main wind turbine blade 21 and the secondary sweeping circle 42 of the secondary wind turbine blade 41 partially overlap on the frontal projection plane. While maintaining the diameter of the main wind turbine blade 21, the secondary wind turbine blade 41 can also have a larger diameter, and a safe distance can be maintained between the secondary wind turbine blade 41 and the ground. The frontal projection plane is the projection facing the main wind turbine blade 21; Figure 5 In, that is, the projection viewed from front to back; in Figure 2 The middle refers to the projection viewed from left to right.

[0037] In this embodiment, the secondary fan 40 is located within the range of 1 / 2 to 5 / 6 of the total height of the tower 10. The center line connecting the two secondary fans 40 is perpendicular to the axis of the tower 10, and the two secondary fan blades 41 do not intersect each other, thus avoiding mutual interference during rotation. By utilizing the weight of the secondary fans 40 and the symmetrical layout, the overall center of gravity of the tower is effectively reduced, thereby reducing the swaying and fatigue damage of the tower under complex weather conditions such as strong winds and turbulence.

[0038] In the preferred embodiment, the secondary fan 40 is located at 2 / 3 of the total height of the tower 10.

[0039] In this embodiment, the diameter of the secondary blade 41 in the secondary fan 40 is 1 / 3 of the diameter of the main blade 21 in the main fan 20.

[0040] This size design balances wind energy capture efficiency with structural rationality. It can supplement wind energy capture through secondary blades while avoiding problems such as increased support load and aggravated airflow interference caused by excessively large secondary blades. At the same time, the symmetrical layout can effectively optimize the distribution of the tower's center of gravity.

[0041] In this embodiment, the distance between the center of the secondary fan 40 and the outer wall of the tower 10 is greater than the radius of the sweeping circle 42 of the secondary fan blade 41, so as to prevent the secondary fan blade 41 from interfering with the tower 10.

[0042] See Figure 3 ,4 The support frame 30 includes two cantilever frames 31. One end of each cantilever frame 31 has an arc-shaped connecting portion 32, and the upper, lower, or end of the other end has a mounting platform 33 for installing the secondary fan 40. The arc-shaped connecting portion 32 is used for fitting and connecting with the tower 10. An ear plate 34 is fixed to the end of the arc-shaped connecting portion 32, and the ear plate 34 has a through hole 35. The two cantilever frames 31 are symmetrically installed on both sides of the tower 10, with the tower 10 located between the arc-shaped connecting portions 32 on both sides. The ear plates 34 of the two cantilever frames 31 are fixed together by bolts. This structure facilitates the installation of the support frame 30. The cantilever frames 31 are made of high-strength, lightweight alloy material, balancing support strength and lightweight requirements. They can effectively transmit the torque generated by the rotation of the secondary fan blades, preventing deformation or breakage of the support frame. Furthermore, the length of the cantilever frame 31 is greater than the radius of the secondary fan blade 41.

[0043] The main blade installation, support fixing, and secondary blade assembly processes of this invention are all mature technologies in the field of wind power generation. They do not require breakthroughs in existing manufacturing and construction processes and can be directly applied to newly built wind turbines or used for the retrofitting and upgrading of existing wind turbines. They are suitable for various conventional onshore wind farm scenarios, with low retrofitting difficulty and short cycle, making them easy to promote and apply on a large scale.

[0044] Example 2: This invention also proposes an operation control method for a single-tower, three-blade wind turbine system, applied to the single-tower, three-blade wind turbine system in Example 1. The operation method includes the following steps: S1. Real-time acquisition of root bending moment signals of each blade of the secondary fan 40, real-time azimuth angle signals of each blade, and vibration acceleration signals of the support 30.

[0045] Specifically, the blade root bending moment signal is collected by strain gauges or strain plates installed at the root of each blade of the secondary wind turbine 41. The real-time azimuth signal is acquired by a high-precision absolute encoder installed on the low-speed shaft of the secondary blade 41 pitch, with vertical upward defined as 0 degrees and vertical downward as 180 degrees. Vibration acceleration signals are collected by an acceleration sensor installed at the end of the support 30 and used for feedback compensation to prevent the pitching action from triggering resonance in the support.

[0046] S2. Perform multi-blade coordinate transformation, using Coleman transformation or Park transformation algorithms to convert the blade root bending moment signal of each blade in the rotating coordinate system into overturning moment components and yaw moment components in the stationary coordinate system.

[0047] Specifically, obtain the azimuth angles of the three blades. Leaf root oscillation torque ; By transforming the matrix Mapped to overturning moment in stationary coordinate system and yaw moment ; Under overlapping operating conditions, key extraction The component represents the degree of force imbalance on the left and right sides caused by the secondary blade 41 entering and exiting the wake region of the main blade 21.

[0048] S3. Generate independent pitch compensation commands. Based on the overturning moment component and the yaw moment component, calculate the independent pitch correction for each blade. When a blade is detected to enter the wake overlap area of ​​the main wind turbine 20, reduce the pitch angle of that blade to compensate for the wind speed loss. When a blade is detected to exit the overlap area, increase the pitch angle of that blade to suppress the load impact.

[0049] Specifically, model predictive control (MPC) or high-order PID control algorithms are employed, and a feedforward compensation mechanism is introduced. Based on the wake boundary model of the main blade 21, which is pre-established through computational fluid dynamics simulation, and combined with the real-time azimuth angle of the secondary blade 41, the timing of the blades entering or leaving the overlap zone is predicted, and pitch trend commands are generated in advance. The frequency components of the independent pitch correction mainly include the first and second harmonics of the rotational speed of the secondary blade 41, in order to accurately counteract periodic aerodynamic disturbances.

[0050] S4. Execute high-frequency pitch control action, superimpose the independent pitch correction amount onto the unified pitch reference command, and drive the high dynamic response pitch actuator of each blade to make real-time angle adjustments.

[0051] Specifically, the pitch drive uses a high-dynamic servo motor or a high-frequency hydraulic proportional valve. The pitch rate capability is no less than 10 degrees / second, and the repeatability accuracy meets the millisecond-level response requirements. The controller and the actuator communicate via EtherCAT or CANopen real-time industrial bus to ensure that the end-to-end delay from data acquisition to action execution is less than 5 milliseconds.

[0052] During operation, the response status of each blade pitch actuator is monitored in real time. If an execution abnormality or excessive fatigue accumulation is detected, the system immediately switches to a unified pitch mode and performs a safe shutdown.

[0053] The above scheme can generate pitch trend commands in advance before the secondary wind turbine enters or exits the wake boundary. Combined with high dynamic servo drive, the end-to-end control delay is compressed to within milliseconds. This not only smooths out power fluctuations caused by sudden changes in wind speed and improves the quality of grid-connected power, but also avoids instantaneous damage to the mechanical transmission chain by load impact peaks, thus improving the stability of the secondary wind turbine in complex wake fields.

[0054] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A single-tower, three-blade wind turbine generator system, characterized in that, include: Tower (10); The main fan (20) is installed at the top of the tower (10); Two secondary fans (40) are located below the main fan (20), and the two secondary fans (40) are respectively installed on the radial sides of the tower (10) by brackets (30); The rotation plane of the main blade (21) in the main fan (20) is parallel to and staggered from the rotation plane of the secondary blade (41) in the secondary fan (40), so that the main blade (21) and the secondary blade (41) do not interfere with each other when they rotate.

2. The single-tower, three-blade wind turbine generator system according to claim 1, characterized in that: The main blade (21) is located in front of the secondary blade (41).

3. The single-tower, three-blade wind turbine generator system according to claim 1 or 2, characterized in that: The main sweep circle (22) of the main blade (21) and the secondary sweep circle (42) of the secondary blade (41) partially overlap on the frontal projection plane.

4. The single-tower, three-blade wind turbine generator system according to claim 1, characterized in that: The secondary fan (40) is located within 1 / 2 to 5 / 6 of the total height of the tower (10).

5. The single-tower, three-blade wind turbine generator system according to claim 4, characterized in that: The secondary fan (40) is located at 2 / 3 of the total height of the tower (10).

6. The single-tower, three-blade wind turbine generator system according to claim 1, characterized in that: The line connecting the centers of the two secondary fans (40) is perpendicular to the central axis of the tower (10).

7. The single-tower, three-blade wind turbine generator system according to claim 1, characterized in that: The diameter of the secondary blade (41) in the secondary fan (40) is 1 / 3 of the diameter of the main blade (21) in the main fan (20).

8. The single-tower, three-blade wind turbine generator system according to claim 1, characterized in that: The support (30) includes two symmetrically arranged cantilever frames (31). One end of the cantilever frame (31) is fixed with an arc-shaped connecting part (32) adapted to the outer wall of the tower (10). The end of the arc-shaped connecting part (32) is fixed with an ear plate (34) with a through hole (35). The two cantilever frames (31) are fastened to the tower (10) by the ear plate (34) and bolts. The other end of the cantilever frame (31) is provided with an installation platform (33) for installing the secondary fan (40).

9. The single-tower, three-blade wind turbine generator system according to claim 1, characterized in that: The distance between the center of the secondary fan (40) and the outer wall of the tower (10) is greater than the radius of the secondary fan blade (41) sweeping circle (42).

10. A method for operating and controlling a single-tower, three-rotor wind turbine system, applied to the single-tower, three-blade wind turbine system as described in any one of claims 1-9, the method comprising the following steps: S1. Collect the bending moment at the root of the secondary fan blades, the blade azimuth angle, and the vibration signal of the support frame. S2. Convert the torque in the rotating coordinate system into the overturning torque and yaw torque in the stationary coordinate system through coordinate transformation; S3. Based on torque signal and wake model, predict the entry / exit of blades into / out of the main wind turbine wake zone and output independent pitch compensation command in advance. S4. The compensation command is superimposed on the reference pitch command to drive the high dynamic servo mechanism to perform pitch control, smoothing power fluctuations, reducing impact loads, and ensuring stable operation of the unit.

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