Shock absorber capable of simultaneously controlling two-order vibration mode vibration of wind power tower drum

Abstract

The invention discloses a shock absorber for simultaneously controlling two-order vibration mode vibration of a wind power tower. The shock absorber comprises the wind power tower, a first-order vibration mode module and a second-order vibration mode module, wherein the first-order vibration mode module and the second-order vibration mode module are arranged in the wind power tower; the first-order vibration mode module comprises a first-order vibration mode mass block and a shape memory alloy variable stiffness support, the first-order vibration mode mass block is hung through a sling, and the interior of the first-order vibration mode mass block is separated to form a U-shaped liquid channel to achieve liquid tuning control; the second-order vibration mode module comprises a second-order vibration mode mass block and an inerter damper, the second-order vibration mode mass block is connected with the bottom face of the first-order vibration mode mass block through a prestress zipper, a bowl-shaped swing mass block is arranged in the second-order vibration mode mass block, and the second-order vibration mode mass block is filled with liquid. The two-order vibration mode mass block is connected in series through the prestress zipper, two-order vibration mode linkage control and first-order vibration mode mass efficiency improvement are achieved, nonlinear variable stiffness and automatic reset are provided through shape memory alloy variable stiffness support, the second-order vibration mode control effect is enhanced in cooperation with the inerter damper and the swing mass block, and the vibration mode control effect is improved. And the wind-induced vibration response is effectively inhibited in a limited tower cylinder space.

Description

Technical Field

[0001] This invention relates to the field of wind turbine tower technology, and more specifically to a vibration damper that simultaneously controls two modes of vibration of a wind turbine tower. Background Technology

[0002] Wind power is a renewable and clean energy source that has attracted widespread attention and research worldwide. With the continuous advancements in wind turbine technology, the height of wind turbine towers has gradually increased, as has the mass at the top. Consequently, wind turbine towers are highly flexible structures, exhibiting more significant structural responses under wind loads, which can even affect the normal operation of the entire tower. Therefore, controlling the wind-induced vibration response of wind turbine tower structures is a pressing issue, and the development of control devices is a crucial aspect of this process.

[0003] Currently, tuned mass damping systems are the main technical means to control the wind vibration response of wind turbine towers, and there has been a great deal of research and patents on this. However, due to the limitations of tower installation space, there is currently no device that can simultaneously control the first and second modes of vibration of wind turbine towers, and high-flexibility tower structures can only effectively control their wind vibration response by controlling the first two modes of vibration simultaneously.

[0004] Existing technologies have two important problems:

[0005] Firstly, due to the limited installation space of the tower, an independent mass system cannot meet the large mass requirements for vibration reduction. To address this issue, this invention connects the mass controlling the first mode shape and the mass controlling the second mode shape through prestressed cables, achieving a significant increase in the mass controlling the first mode shape without increasing the installation space. Simultaneously, an inertial capacitive damper is added at the control position of the second mode shape to enhance mass efficiency, further increasing the mass controlling the second mode shape.

[0006] Secondly, current technologies can only address the control of the first or second mode of vibration of wind turbine towers, and cannot achieve simultaneous control of both modes. For highly flexible towers, controlling both modes simultaneously is essential for effectively managing their wind-induced vibration response.

[0007] Therefore, in order to solve the problems of insufficient quality due to limited installation space and inability to simultaneously control the first and second modes of wind turbine towers in the existing technology, it is an urgent problem for those skilled in the art to solve the problem of providing a vibration damper technology that can achieve linkage control of two modes of vibration without increasing installation space and effectively improve the control quality. Summary of the Invention

[0008] In view of this, the present invention provides a vibration damper that simultaneously controls the two modes of vibration of a wind turbine tower, aiming to solve the above-mentioned technical problems.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A vibration damper that simultaneously controls two modes of vibration of a wind turbine tower includes: a wind turbine tower; and a first-mode vibration module and a second-mode vibration module disposed inside the wind turbine tower. The first-order mode shape module includes a first-order mode shape mass block and shape memory alloy variable stiffness supports. The top surface of the first-order mode shape mass block is connected to the inner top wall of the wind turbine tower via a sling. The interior of the first-order mode shape mass block is divided into two vertically arranged chambers, and liquid tuning control is achieved through a U-shaped liquid channel formed within the chambers. There are multiple shape memory alloy variable stiffness supports, which are arranged around the first-order mode shape mass block and connected to the inner side wall of the wind turbine tower. All of the multiple shape memory alloy variable stiffness supports abut against the outer wall of the first-order mode shape mass block. The second-order mode module includes a second-order mode mass block and an inertial-capacitive damper; the top surface of the second-order mode mass block is connected to the bottom surface of the first-order mode mass block by a prestressed cable; the second-order mode mass block is hollow and filled with liquid; a bowl-shaped swinging mass block is provided inside the second-order mode mass block; there are multiple inertial-capacitive dampers, which are arranged around the second-order mode mass block and connected between the outer wall of the second-order mode mass block and the inner wall of the wind turbine tower.

[0010] Through the above technical solution, this invention connects the first-order mode mass block and the second-order mode mass block in series using prestressed cables, achieving coordinated control of the two modes of vibration. Simultaneously, it significantly increases the control equivalent mass of the first-order mode without occupying additional tower installation space. Utilizing shape memory alloy variable stiffness supports provides nonlinear variable stiffness characteristics—low stiffness under small deformation and high stiffness under large deformation—and accurate reset capability, combined with U-shaped liquid channels inside the first-order mode mass block, achieves liquid-tuned vibration reduction. The second-order mode module achieves mass enhancement through an inertial-capacitive damper, and, combined with the swaying motion of the internal bowl-shaped rocking mass block and the buffering effect of the filling liquid, significantly enhances the control effect on the second-order mode. Overall, this vibration damper effectively suppresses both the first-order and second-order wind-induced vibration responses of the wind turbine tower within a limited space, improving the structural safety and wind resistance performance of the highly flexible tower.

[0011] Preferably, in the above-mentioned vibration damper that simultaneously controls the vibration of two modes of a wind turbine tower, the first mode mass block has a drum-shaped structure that is narrow at the top and bottom and wide in the middle. The interior of the first mode mass block is divided into two chambers, upper and lower, by a horizontal partition. Both chambers are fixed with an inner partition shell by a support rod, so that a gap is formed between the inner partition shell and the chamber. Injecting liquid into the gap can form the U-shaped liquid channel.

[0012] Preferably, in the above-mentioned vibration damper that simultaneously controls the two modes of vibration of the wind turbine tower, the liquid surfaces of the two U-shaped liquid channels are covered with annular cover plates.

[0013] Preferably, in the above-mentioned vibration damper that simultaneously controls the two modes of vibration of a wind turbine tower, the liquid in the U-shaped liquid channel and the liquid inside the second-mode mass block are both dimethyl silicone oil.

[0014] Preferably, in the above-mentioned vibration damper that simultaneously controls the vibration of two modes of a wind turbine tower, the shape memory alloy variable stiffness support is an arched structure, and the arched side of the shape memory alloy variable stiffness support abuts against the outer wall of the first mode mass block.

[0015] Preferably, in the above-mentioned vibration damper that simultaneously controls the two modes of vibration of a wind turbine tower, the shape memory alloy variable stiffness support is connected to the wind turbine tower through a slotted fixing frame. One side of the slotted fixing frame is fixed to the wind turbine tower, and the other side of the slotted fixing frame has a slot. The upper and lower ends of the shape memory alloy variable stiffness support are respectively engaged in the slot, so that the shape memory alloy variable stiffness support forms the arched structure.

[0016] Preferably, in the above-mentioned vibration damper that simultaneously controls the vibration of two modes of a wind turbine tower, the two ends of the prestressed zipper are respectively connected to the top surface of the second-mode mass block and the bottom surface of the first-mode mass block through anchors.

[0017] Preferably, in the above-mentioned vibration damper that simultaneously controls the two modes of vibration of a wind turbine tower, the bowl-shaped rocking mass block is a solid structure, and its arc-shaped bottom surface is placed on the inner bottom surface of the second mode mass block.

[0018] Preferably, in the above-mentioned vibration damper that simultaneously controls the vibration of two modes of a wind turbine tower, the first mode mass block is located at the top of the wind turbine tower, and the second mode mass block is located in the middle of the wind turbine tower.

[0019] Preferably, in the above-mentioned vibration damper that simultaneously controls the two modes of vibration of the wind turbine tower, the length of the prestressed ties is greater than the length of the suspension cables.

[0020] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a vibration damper that simultaneously controls the two modes of vibration of a wind turbine tower, which has the following beneficial effects: 1. Achieve two-mode linkage control: By connecting the first-mode mass block and the second-mode mass block in series with prestressed cables, the first and second modes of the wind turbine tower can be controlled simultaneously, effectively suppressing the wind-induced vibration response of the highly flexible tower.

[0021] 2. High space utilization and significant quality improvement: The series structure significantly improves the control equivalent mass of the first-order vibration mode without increasing the internal installation space of the tower; at the same time, the second-order vibration mode module achieves quality improvement through the inertial capacitive damper, further enhancing the vibration reduction effect.

[0022] 3. Variable stiffness control and automatic reset: The shape memory alloy variable stiffness support with an arch structure provides small stiffness during small deformation and large stiffness during large deformation, realizing nonlinear stiffness adjustment, and utilizes the reset characteristics of the shape memory alloy to ensure accurate return to position after vibration.

[0023] 4. Multi-mechanism synergistic vibration reduction: The first-order vibration mode mass block is equipped with a U-shaped liquid channel and an annular cover plate to achieve liquid tuning vibration reduction; the second-order vibration mode mass block is equipped with a bowl-shaped rocking mass block filled with dimethyl silicone oil, which enhances the control effect of the second-order vibration mode through rocking motion and liquid buffering.

[0024] 5. Prestress is generated naturally and is adjustable: The gravity of the second-order mode mass block applies prestress to the first-order mode mass block through the prestressed cable. The magnitude of the prestress can be easily adjusted by adjusting the mass at the lower end, providing convenient conditions for stiffness adjustment. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 A schematic diagram of the structure of the vibration damper that simultaneously controls two modes of vibration of a wind turbine tower, provided by the present invention; Figure 2 A cross-sectional view of the vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower, provided by the present invention; Figure 3 A schematic diagram of the internal structure of a first-order mode mass block provided by the present invention; Figure 4 A cross-sectional view of the first-order vibration mode mass block under liquid injection state provided by the present invention; Figure 5 An exploded view of the structure of the shape memory alloy variable stiffness support and the grooved fixing frame provided by the present invention; Figure 6 This is a schematic diagram of the internal structure of the second-order mode mass block provided by the present invention; Figure 7 This is a cross-sectional view of the second-order vibration mode mass block under liquid injection state provided by the present invention.

[0027] in: 1-Wind turbine tower; 2-First-order mode shape module; 21-First-order mode shape mass block; 211-U-shaped liquid channel; 212-Horizontal partition; 213-Support rod; 214-Inner partition shell; 215-Annular cover plate; 22-Shape memory alloy variable stiffness support; 23-Sling; 24-Slotted fixing frame; 241-Slot opening; 3-Second-order mode module; 31-Second-order mode mass block; 32-Inertial-capacitive damper; 33-Prestressed zipper; 34-Bowl-shaped swing mass block; 35-Anchor. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] See appendix Figure 1 To be continued Figure 7 The present invention discloses a vibration damper that simultaneously controls the two modes of vibration of a wind turbine tower, comprising: a wind turbine tower 1; and further comprising a first-mode vibration module 2 and a second-mode vibration module 3 disposed inside the wind turbine tower 1; The first-order mode module 2 includes a first-order mode mass block 21 and a shape memory alloy variable stiffness support 22. The top surface of the first-order mode mass block 21 is connected to the inner top wall of the wind turbine tower 1 through a sling 23. The interior of the first-order mode mass block 21 is divided into two vertically arranged chambers, and liquid tuning control is achieved through a U-shaped liquid channel 211 formed in the chamber. There are multiple shape memory alloy variable stiffness supports 22, which are arranged around the first-order mode mass block 21 and connected to the inner side wall of the wind turbine tower 1. All of the multiple shape memory alloy variable stiffness supports 22 abut against the outer wall of the first-order mode mass block 21. The second-order mode module 3 includes a second-order mode mass block 31 and an inertial-capacitive damper 32. The top surface of the second-order mode mass block 31 is connected to the bottom surface of the first-order mode mass block 21 through a prestressed cable 33. The second-order mode mass block 31 is hollow and filled with liquid. A bowl-shaped swing mass block 34 is provided inside the second-order mode mass block 31. There are multiple inertial-capacitive dampers 32, which are arranged around the second-order mode mass block 31 and connected between the outer wall of the second-order mode mass block 31 and the inner wall of the wind turbine tower 1.

[0030] See appendix Figure 3 and attached Figure 4The first-order mode mass block 21 has a drum-shaped structure that is narrow at the top and bottom and wide in the middle. The interior of the first-order mode mass block 21 is divided into two chambers, upper and lower, by a horizontal partition 212. Both chambers are fixed with an inner partition shell 214 by a support rod 213, so that a gap is formed between the inner partition shell 214 and the chamber. Injecting liquid into the gap can form a U-shaped liquid channel 211.

[0031] To further optimize the above technical solution, the liquid surfaces of both U-shaped liquid channels 211 are covered with annular cover plates 215.

[0032] See appendix Figure 5 The shape memory alloy variable stiffness support 22 is an arched structure, and the arched side of the shape memory alloy variable stiffness support 22 abuts against the outer wall of the first-order vibration mode mass block 21.

[0033] To further optimize the above technical solution, the shape memory alloy variable stiffness support 22 is connected to the wind turbine tower 1 through a groove-shaped fixing frame 24. One side of the groove-shaped fixing frame 24 is fixed to the wind turbine tower 1, and the other side of the groove-shaped fixing frame 24 has a groove 241. The upper and lower ends of the shape memory alloy variable stiffness support 22 are respectively engaged in the groove 241, so that the shape memory alloy variable stiffness support 22 forms an arch structure.

[0034] See appendix Figure 2 The two ends of the prestressed zipper 33 are connected to the top surface of the second-order mode mass block 31 and the bottom surface of the first-order mode mass block 21 through anchors 35, respectively.

[0035] See appendix Figure 6 and attached Figure 7 The bowl-shaped rocking mass block 34 is a solid structure, and its arc-shaped bottom surface is placed on the inner bottom surface of the second-order mode mass block 31.

[0036] To further optimize the above technical solution, the first-order vibration mode mass block 21 is located at the top of the wind turbine tower 1, and the second-order vibration mode mass block 31 is located in the middle of the wind turbine tower 1.

[0037] To further optimize the above technical solution, the length of the prestressed zipper 33 is greater than the length of the sling 23.

[0038] The following is in conjunction with the appendix Figure 1 To be continued Figure 7 The working principle of the vibration damper that simultaneously controls the two modes of vibration of wind turbine towers provided by the present invention will be described in detail below: When the wind turbine tower 1 vibrates under wind load, the first-order vibration mode module 2 and the second-order vibration mode module 3 work together to control the first-order and second-order vibration modes of the tower, respectively.

[0039] Specifically, a first-order mode mass block 21 located at the top of the wind turbine tower 1 is suspended by a cable 23, forming a first-order tuned mass damping system. When the tower generates first-order mode vibration, the first-order mode mass block 21 moves relative to the tower, and the liquid in its two internal chambers generates tuned sloshing through the U-shaped liquid channel 211, thereby dissipating vibration energy. Simultaneously, multiple shape memory alloy variable stiffness supports 22 arranged around the first-order mode mass block 21 provide variable stiffness control for the first-order mode. The shape memory alloy variable stiffness supports 22 have an arched structure, with their arched sides abutting against the outer wall of the first-order mode mass block 21. When the vibration amplitude is small, the stiffness generated by the support is small; when the vibration amplitude increases, the support is further compressed, and the stiffness increases accordingly, achieving a nonlinear stiffness characteristic of small stiffness under small deformation and large stiffness under large deformation. Furthermore, the shape memory alloy material has a good shape memory effect, enabling the support to accurately return to its original position after vibration ends.

[0040] The second-order mode mass block 31, located in the middle of the wind turbine tower 1, is connected to the bottom surface of the first-order mode mass block 21 via a prestressed cable 33, thereby connecting the control masses of the two modes in series. On the one hand, the first-order mode mass block 21 drives the second-order mode mass block 31 through the prestressed cable 33, which significantly increases the equivalent mass controlling the first-order mode, achieving mass efficiency enhancement without occupying additional tower installation space. On the other hand, the weight of the second-order mode mass block 31 itself applies prestress to the first-order mode mass block 21 through the prestressed cable 33. The magnitude of the prestress can be adjusted by adjusting the mass of the lower second-order mode mass block 31, providing convenient conditions for adjusting the stiffness of the first-order mode.

[0041] The second-order mode module 3 is connected to the inner wall of the wind turbine tower 1 via an inertial-capacitive damper 32. When the tower generates second-order mode vibration, the second-order mode mass block 31 moves relative to the tower. The inertial-capacitive damper 32 generates a mass enhancement effect, significantly increasing the equivalent mass controlling the second-order mode, thereby effectively suppressing the vibration caused by the second-order mode. Simultaneously, the second-order mode mass block 31 is hollow and filled with dimethyl silicone oil, and contains a bowl-shaped rocking mass block 34. The arc-shaped bottom surface of the bowl-shaped rocking mass block 34 rests on the inner bottom surface of the second-order mode mass block 31. During vibration, the bowl-shaped rocking mass block 34 rocks, further enhancing the control effect on the second-order mode; the internal dimethyl silicone oil acts as a buffer against the rocking motion, preventing violent collisions of the mass block.

[0042] In addition, the liquid surfaces of the two U-shaped liquid channels 211 inside the first-order mode mass 21 are covered with annular cover plates 215, which can enhance the liquid tuning effect. The liquid in the U-shaped liquid channels 211 and the liquid inside the second-order mode mass 31 are both made of dimethyl silicone oil, which has excellent viscosity-temperature characteristics and damping performance, and can stably dissipate vibration energy.

[0043] In summary, this invention achieves coordinated control of two vibration modes by connecting the first-order mode mass block 21 and the second-order mode mass block 31 in series using a prestressed cable 33; it provides nonlinear variable stiffness and automatic reset functions using a shape memory alloy variable stiffness support 22; it achieves liquid tuning vibration reduction using a U-shaped liquid channel 211 and an annular cover plate 215; it enhances the mass efficiency of second-order mode control using an inertial capacitive damper 32; and it enhances the second-order mode control effect and buffers motion using a bowl-shaped rocking mass block 34 and dimethyl silicone oil. The synergistic action of these components effectively controls both the first and second-order mode vibrations of the wind turbine tower within the limited tower installation space.

[0044] Example 1: Taking a certain type of wind turbine tower as an example, the total height of wind turbine tower 1 is 10 meters. The first-order vibration mode module 2 is set at the top of the tower, and the second-order vibration mode module 3 is set in the middle of the tower.

[0045] The suspension cable 23 is 0.5 meters long, allowing the first-order mode mass block 21 to be suspended 0.5 meters below the top wall of the tower. The first-order mode mass block 21 is constructed of steel to ensure sufficient rigidity and mass. The prestressed cable 33 is 5 meters long, with one end connected to the bottom surface of the first-order mode mass block 21 via anchor 35, and the other end connected to the top surface of the second-order mode mass block 31 via anchor 35. At this point, the second-order mode mass block 31 is located at a height of approximately 5.5 meters in the middle of the tower (measured downwards from the top), matching the position of the inflection point of the second-order mode of the tower.

[0046] Eight shape memory alloy variable stiffness supports 22 are uniformly arranged around the circumference of the first-order mode mass block 21. Each shape memory alloy variable stiffness support 22 is connected to the inner wall of the wind turbine tower 1 through a channel-shaped fixing frame 24, and its arched side abuts against the outer wall of the first-order mode mass block 21. The eight uniformly arranged supports can provide isotropic variable stiffness constraints, effectively controlling the vibration of the first-order mode in all directions.

[0047] There are also eight inertial-capacitive dampers 32, which are evenly arranged around the circumference of the second-order mode mass block 31. Each inertial-capacitive damper 32 is connected between the outer wall of the second-order mode mass block 31 and the inner wall of the wind turbine tower 1. The eight evenly distributed inertial-capacitive dampers 32 can simultaneously produce mass enhancement effects in all directions, significantly improving the control effect on the second-order mode.

[0048] The second-order mode mass 31 is constructed of steel or aluminum alloy (steel or aluminum alloy can be selected according to actual weight requirements). The internal filling liquid and the liquid in the U-shaped liquid channel 211 within the first-order mode mass 21 are both made of dimethyl silicone oil. Dimethyl silicone oil has excellent viscosity-temperature characteristics and chemical stability, maintaining stable damping performance over a wide temperature range, ensuring reliable operation of the vibration damper under various environmental conditions.

[0049] The bowl-shaped oscillating mass block 34 is a solid steel structure. Its arc-shaped bottom surface is placed on the inner bottom surface of the second-order vibration mode mass block 31. It can oscillate freely during vibration, further enhancing the energy dissipation effect of the second-order vibration mode.

[0050] In this embodiment, by setting the specific parameters mentioned above, coordinated control of the first-order and second-order vibration modes was achieved within the limited internal space of a 10-meter-high wind turbine tower, significantly improving the wind resistance performance of the highly flexible wind turbine tower.

[0051] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0052] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vibration damper that simultaneously controls two modes of vibration of a wind turbine tower, comprising: Wind turbine tower (1); characterized in that it further includes a first-order vibration mode module (2) and a second-order vibration mode module (3) disposed inside the wind turbine tower (1); The first-order mode module (2) includes a first-order mode mass block (21) and a shape memory alloy variable stiffness support (22). The top surface of the first-order mode mass block (21) is connected to the inner top wall of the wind turbine tower (1) by a sling (23). The first-order mode mass block (21) is divided into two chambers arranged vertically, and liquid tuning control is achieved through a U-shaped liquid channel (211) formed in the chamber. There are multiple shape memory alloy variable stiffness supports (22). Multiple shape memory alloy variable stiffness supports (22) are arranged around the first-order mode mass block (21) and connected to the inner side wall of the wind turbine tower (1). Multiple shape memory alloy variable stiffness supports (22) abut against the outer wall of the first-order mode mass block (21). The second-order mode module (3) includes a second-order mode mass block (31) and an inertial-capacitive damper (32); the top surface of the second-order mode mass block (31) is connected to the bottom surface of the first-order mode mass block (21) through a prestressed zipper (33); the second-order mode mass block (31) is hollow inside and filled with liquid; a bowl-shaped swing mass block (34) is provided inside the second-order mode mass block (31); there are multiple inertial-capacitive dampers (32); multiple inertial-capacitive dampers (32) are arranged around the second-order mode mass block (31) and connected between the outer wall of the second-order mode mass block (31) and the inner wall of the wind turbine tower (1).

2. The vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 1, characterized in that, The first-order mode mass block (21) has a drum-shaped structure that is narrow at the top and bottom and wide in the middle. The interior of the first-order mode mass block (21) is divided into two chambers, upper and lower, by a horizontal partition (212). Both chambers are fixed with an inner partition shell (214) by a support rod (213), so that a gap is formed between the inner partition shell (214) and the chamber. Injecting liquid into the gap can form the U-shaped liquid channel (211).

3. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 3, characterized in that, The liquid surfaces of both U-shaped liquid channels (211) are covered with annular cover plates (215).

4. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 3, characterized in that, The liquid in the U-shaped liquid channel (211) and the liquid inside the second-order mode mass block (31) are both dimethyl silicone oil.

5. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 1, characterized in that, The shape memory alloy variable stiffness support (22) is an arched structure, and the arched side of the shape memory alloy variable stiffness support (22) abuts against the outer wall of the first-order mode mass block (21).

6. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 5, characterized in that, The shape memory alloy variable stiffness support (22) is connected to the wind turbine tower (1) through a groove-shaped fixing frame (24). One side of the groove-shaped fixing frame (24) is fixed to the wind turbine tower (1), and the other side of the groove-shaped fixing frame (24) has a groove (241). The upper and lower ends of the shape memory alloy variable stiffness support (22) are respectively engaged in the groove (241), so that the shape memory alloy variable stiffness support (22) forms the arch structure.

7. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 1, characterized in that, The two ends of the prestressed zipper (33) are connected to the top surface of the second-order mode mass block (31) and the bottom surface of the first-order mode mass block (21) respectively by anchors (35).

8. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 1, characterized in that, The bowl-shaped rocking mass block (34) is a solid structure, and its arc-shaped bottom surface is placed on the inner bottom surface of the second-order mode mass block (31).

9. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 1, characterized in that, The first-order mode mass block (21) is located at the top of the wind turbine tower (1), and the second-order mode mass block (31) is located in the middle of the wind turbine tower (1).

10. A vibration damper for simultaneously controlling two modes of vibration of a wind turbine tower according to claim 9, characterized in that, The length of the prestressed zipper (33) is greater than the length of the sling (23).

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