A variable-stiffness magneto-inertance-capacitance adaptive damper for a fan structure

Abstract

The present invention discloses a variable-stiffness magneto-inertial-capacitance adaptive damper for a fan structure. The top end of the mass ball is connected to the bottom end of the pendulum rope, and the top end of the pendulum rope is connected to the top of the tower. The bottom of the mass ball is movably connected to the sliding rod through an upper spherical hinge. The bottom end of the sliding rod passes through the inertial capacitor, and the bottom end of the sliding rod is connected to the bottom of the tower through a lower swing rod. The variable-stiffness spring, the magnetorheological damper, and the inertial capacitor are connected in parallel and arranged vertically. One end of the variable-stiffness spring is connected to the stepping motor. The structure of the present invention is reasonable. Based on the mass amplification effect of the inertial capacitor, the additional mass of the pendulum type tuned mass damper is effectively reduced and the control effect of the damper is improved, thereby achieving higher cost performance. Based on the variable-stiffness spring and the magnetorheological damper, the self-adaptability of the damper is realized, ensuring its reliability under various loads and improving the robustness of the system. The "flexible cable" connection method suitable for the structural characteristics of the fan is adopted, effectively reducing the swing angle of the mass block and reducing the risk of collision.

Description

Technical Field

[0001] The present invention relates to the field of vibration control technology, in particular to a variable stiffness magneto-inertia adaptive damper for a fan structure. Background Art

[0002] As an environmentally friendly, renewable, and clean energy source, wind energy plays a vital role in achieving carbon neutrality and carbon peak. To more efficiently develop and utilize wind energy, wind turbines are rapidly developing towards larger, higher-megawatt sizes. This is accompanied by increasing heights and blade lengths, which results in significant structural vibration response under loads such as wind, earthquakes, and waves. Excessive vibration response can lead to component fatigue or even damage, reducing the service life of the structure and impacting the performance of the wind turbine. Therefore, it is crucial to reduce the vibration response of wind turbines to ensure their safety, reliability, and resilience under multiple hazards.

[0003] Structural vibration control is an effective means of reducing structural vibration response and improving its safety, reliability, and resilience. Based on their operating mechanisms, existing vibration control technologies can be roughly divided into four categories: passive control, active control, semi-active control, and hybrid control. Passive control technology, which requires no external excitation or energy input, offers numerous advantages in terms of vibration reduction effectiveness, reliability, and maintenance, making it a commonly used vibration control method in engineering. Common passive control technologies include foundation isolation, energy-dissipating vibration reduction, and tuned vibration reduction. Research has shown that all three passive control technologies can suppress structural vibration response. Tuned vibration reduction, typically consisting of components such as a mass, springs, and dampers, provides efficient vibration control within a specific frequency range and is widely applicable to various types of structures and systems. Therefore, it has a wide range of engineering applications in the field of vibration control.

[0004] The basic working principle of tuned vibration reduction technology is to suppress the vibration response of the main structure through "reverse" resonance. The specific working process is as follows: (1) Interaction effect: The main structure begins to vibrate, transferring energy to the additional mass and spring. (2) Energy absorption: The damper absorbs and dissipates the energy during the vibration process, thereby limiting the amplitude of the main structure. In this way, TMD helps the main structure maintain a smaller vibration amplitude, reducing the risk of structural stress and fatigue. (3) Damping effect: The additional mass begins to vibrate with the main structure, but the action of the damper causes the amplitude of the additional mass to gradually decrease. This is the key role of TMD, which reduces the vibration of the main structure through damping.

[0005] The pendulum - type tuned mass damper is a classic implementation of the tuned vibration reduction system, where the pendulum is suspended on the structure. When the ground vibration acts, the system vibrates horizontally, and the pendulum vibrates along with it. The inertial force generated by the vibration of the pendulum reacts on the structure itself. When this inertial force is opposite to the direction of the movement of the structure itself, the vibration reduction effect is produced.

[0006] Although the existing pendulum - type tuned mass dampers can reduce the vibration response of the structure to a certain extent, their application in the vibration control of wind turbines still faces many challenges, as follows:

[0007] (1) The control effect of the pendulum - type tuned mass damper highly depends on the mass ratio, that is, the ratio of the physical mass of the secondary structure to the main structure. Generally speaking, a relatively large secondary mass is required to achieve the desired control performance. However, a large secondary mass not only increases the structural load and thus increases the construction cost, but also increases the complexity of the connection system, which to a certain extent hinders the wide application of the tuned mass damper. (2) The control effect of the pendulum - type tuned mass damper depends on the accurate identification of the dynamic characteristics of the wind turbine structure and the optimal design of the damper. Specifically, the key to achieving efficient vibration control lies in determining the optimal tuning frequency and damping ratio of the damper. However, in practical applications, due to the changes in the structure and the environment, the dynamic characteristics of the structure may change during the entire service life (i.e., time - varying dynamic characteristics). The traditional pendulum - type tuned mass damper has a fixed tuning frequency and damping ratio, and there is a potential risk of a decrease in the control effect (i.e., "detuning"). (3) Under extreme loads (wind, waves, and earthquakes), the mass block of the pendulum - type tuned mass damper may wear and collide with the inner wall of the wind turbine tower, causing local damage or even failure of the structure, affecting the structural safety. Therefore, there is an urgent need for an improved technology to solve this problem existing in the prior art. Summary of the Invention

[0008] The purpose of the present invention is to provide a variable - stiffness magneto - rheological inertia - capacitance adaptive damper for wind turbine structures. Based on the mass amplification effect of the inertance, it can effectively reduce the additional mass of the pendulum - type tuned mass damper and improve the control effect of the damper, thereby achieving higher cost - effectiveness. Based on the variable - stiffness spring and the magneto - rheological damper, the self - adaptability of the damper is realized to ensure its reliability under various loads and improve the robustness of the system. The "flexible cable" connection method suitable for the structural characteristics of the wind turbine is adopted to effectively reduce the swing angle of the mass block and reduce the risk of collision, so as to solve the problems proposed in the above - mentioned background technology.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a variable stiffness magnetorheological damper for a wind turbine structure, the variable stiffness magnetorheological damper being arranged in a tower and comprising a swing rope, a mass ball, an upper ball joint, a slide rod, a stopper, a stepping motor, a variable stiffness spring, a magnetorheological damper, and an inertia container. The top end of the mass ball is connected to the bottom end of the swing rope, which is connected to the top of the tower. The bottom of the mass ball is provided with an upper ball joint, which is movably connected to the slide rod. The bottom end of the slide rod is passed through the inertia container, and the bottom end of the slide rod is connected to the bottom of the tower via a lower swing rod. The variable stiffness spring, magnetorheological damper, and inertia container are connected in parallel and vertically arranged. One end of the variable stiffness spring is connected to the stepping motor. The bottom of the stepping motor, the top of the magnetorheological damper, the bottom of the variable stiffness spring, and the bottom of the magnetorheological damper are all connected to the stopper.

[0010] Preferably, the present invention provides a variable stiffness magneto-inertia adaptive damper for a wind turbine structure, wherein a foundation is provided at the bottom of the tower, a pedestal is provided on the upper surface of the foundation, and a lower swing rod connected to the bottom of the sliding rod is connected to the pedestal through a lower end ball joint.

[0011] Preferably, the present invention provides a variable stiffness magneto-inertia adaptive damper for a fan structure, wherein the upper limiter is welded to the sliding rod.

[0012] Preferably, the present invention provides a variable stiffness magneto-inertia adaptive damper for a fan structure, wherein a spring limit seat is further provided on the upper surface of the limiter located below, and the bottom of the variable stiffness spring is rotatably connected to the spring limit seat.

[0013] Preferably, the present invention provides a variable stiffness magneto-inertia adaptive damper for a wind turbine structure, wherein the number of the swing ropes is at least two.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) By utilizing the mass amplification effect of the inertia container, the apparent mass of the control device is increased, thereby reducing the additional mass of the pendulum tuned mass damper, and achieving a more economical and efficient effect while improving the control effect of the damper.

[0016] (2) The variable stiffness spring and magnetorheological damper are connected in series with the inertia container to achieve the adaptability of the damper, ensure its reliability under various loads, improve the robustness of the system, and thus improve the toughness of the vibration reduction system.

[0017] (3) The damper and the top of the tower are connected by a "flexible rope" method, which effectively reduces the swing angle of the mass block and reduces the risk of collision, thereby improving the stability and durability of the vibration reduction system and facilitating installation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the present invention;

[0019] Figure 2 is an attached Figure 1 schematic enlarged view of the structure at the marked position A in the attached figure;

[0020] Figure 3 is a schematic diagram of the initial state of the mass ball;

[0021] Figure 4 is a schematic diagram of the initial state of the left swing of the mass ball;

[0022] Figure 5 is a schematic diagram of the initial state of the right swing of the mass ball;

[0023] Figure 6 is a schematic diagram of the tower structure.

[0024] In the figure: tower 1, pendulum rope 2, mass ball 3, upper ball hinge 4, sliding rod 5, limiter 6, stepper motor 7, variable stiffness spring 8, magnetorheological damper 9, inertance container 10, bearing platform 11, foundation 12, lower swing rod 13, lower ball hinge 14, spring limit seat 15. DETAILED DESCRIPTION OF THE INVENTION

[0025] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention;

[0026] It should be noted that in the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "inner", "outer", "upper", "lower", "both sides", "one end", "the other end", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention 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 therefore cannot be construed as a limitation of the present invention.

[0027] Please refer to Figures 1-6, the present invention provides a technical solution: a variable-stiffness magneto-inertial adaptive damper for a fan structure. The variable-stiffness magneto-inertial adaptive damper is arranged in the tower 1. The variable-stiffness magneto-inertial adaptive damper includes a pendulum rope 2, a mass ball 3, an upper ball hinge 4, a sliding rod 5, a stopper 6, a stepping motor 7, a variable-stiffness spring 8, a magnetorheological damper 9, and an inertance container 10. The top of the mass ball 3 is connected to the bottom of the pendulum rope 2, and the top of the pendulum rope 2 is connected to the top of the tower 1. An upper ball hinge 4 is arranged at the bottom of the mass ball 3, and the upper ball hinge 4 is movably connected to the sliding rod 5. The bottom end of the sliding rod 5 passes through the inertance container 10, and the bottom end of the sliding rod 5 is connected to the bottom of the tower 1 through a lower swing rod 13. The variable-stiffness spring 8, the magnetorheological damper 9, and the inertance container 10 are connected in parallel and arranged vertically. One end of the variable-stiffness spring 8 is connected to the stepping motor 7. The bottom of the stepping motor 7, the top of the magnetorheological damper 9, the bottom of the variable-stiffness spring 8, and the bottom of the magnetorheological damper 9 are all connected to the stopper 6. Stoppers 6 are installed on both sides to limit the movement range of the variable-stiffness spring 8 and the magnetorheological damper 9 to prevent exceeding safety or design limits. A stepping motor 7 is installed at the end of the variable-stiffness spring 8 and moves according to a fixed stepping angle according to the input pulse signal, thereby adjusting the length of the variable-stiffness spring 8 in real time. The left and right swinging of the mass ball 3 will cause relative movement of the magnetorheological damper 9, achieving the purpose of energy dissipation and vibration reduction, and effectively suppressing vertical and horizontal vibrations. By moving the stepping motor 7 to adjust the length of the spring in real time and changing the current of the magnetorheological damper, continuous variation of stiffness and damping is achieved, which is convenient and fast. The mass ball in this solution can be a pendulum, and the pendulum rope connected to it can also be a rod.

[0028] The present invention is mainly composed of an inertia amplification device, an inertance container, and a pendulum type tuned mass damper, which are connected in series through a ball hinge and a pendulum rope. Here, taking the application of this damper in a fan vibration reduction system as an example to describe how this system works, but this system includes but is not limited to being applied to fans and can also be applied to other structural forms. The specific technical principle is as follows:

[0029] When wind loads act on the wind turbine structure, causing it to vibrate, a mass ball, connected to the structure by a pendulum rope, begins to swing. An inertia container is slidably connected beneath the mass ball. As the mass ball swings, the inertia container slides vertically relative to the mass ball. The mass ball drives the inertia container and the support structure to rotate and oscillate in space. Therefore, during the mass ball's swing, the inertia container exerts no vertical downward force on the mass ball. The horizontal acceleration of the mass ball and the inertia container is provided by the horizontal component of the tension from the pendulum rope and the slide rod, the magnitude of which is solely dependent on the mass of the mass ball. This component not only acts on the structure through the mass ball, reducing structural response and thus achieving a vibration control effect, but also provides a controlling force to the mass ball, reducing its amplitude, thereby effectively minimizing the probability of collision and friction with the tower's inner walls. This allows the mass ball to maintain stability and durability within a relatively small space, freeing up space for other purposes.

[0030] To save space, a variable-stiffness spring, a magnetorheological damper, and an inertia vessel are connected in parallel between the mass ball and the support. A stepper motor is connected to one end of the variable-stiffness spring to convert pulse signals into mechanical motion. This motor, along with the magnetorheological damper, is connected to a real-time detection system. The spring's length and current are adjusted in real time based on the environment and applied loads, controlling the tuning frequency and damper in real time. This optimizes the damper's vibration reduction efficiency and maximizes its damping bandwidth. This system features a wide vibration reduction bandwidth and convenient and fast adaptive adjustment.

[0031] When the structure is subjected to external loads, it drives the pendulum-type tuned inertia mass damper of the present invention to swing left and right. The inertial force generated by the relative motion of mass ball 3 reacts on the structure, maximizing the transfer of the structure's vibration energy to mass ball 3. When subjected to external excitation, the inertia chamber 10 connected to mass ball 3 generates relative acceleration at both ends of the slide bar 5. The inertia chamber 10 generates inertial force, and the mass amplification effect of the inertia chamber 10 increases the apparent mass of the control device while reducing the actual mass of mass ball 3. This force is dissipated by the damping action of the magnetorheological damper 9, thereby reducing the structure's vibration response. When external excitation or changes in the inherent dynamic characteristics of the structure occur, sensors monitor the main structure's vibration and the response characteristics of mass ball 3 in real time. Spectral analysis is then performed, and the optimal stiffness and damping parameters are calculated using a semi-active control algorithm. The tuning frequency and damping ratio of the damper are then controlled in real time, improving vibration reduction efficiency and maintaining optimal vibration reduction results.

[0032] Compared with the existing pendulum tuned mass damper, the present invention reduces the acceleration of the mass ball 3 during its swing by providing the inertia container 10, thereby lowering the applicable frequency of the damper. That is, without increasing the pendulum length of the damper, the damper can be applied to a fan structure with a low vibration frequency and a long period.

[0033] In this technical solution, the frequency of the new damper can be calculated by the following formula:

[0034]

[0035] In the formula, m represents the mass of the mass ball 3, L represents the pendulum length of the pendulum rope 2, m b represents the inertance coefficient of the inertor 10. Its dimension is equivalent to mass, also known as inertance or apparent mass. Its magnitude is related to the relative acceleration magnitude at both ends of the sliding rod 5. k m represents the stiffness of the variable stiffness spring 8.

[0036] As can be seen from the above formula, by increasing the mass of the inertor 10, it is possible to reduce the vibration frequency range applicable to the damper without increasing the pendulum length of the damper; or by increasing the mass of the inertor 10, it is possible to reduce the pendulum length of the damper without changing the vibration frequency range applicable to the damper, so that the damper can be applied to structures with limited installation space. Compared with traditional mass elements, the advantage of inertance elements lies in that when adjusting the structural inertia characteristics, it is not limited to single-end connection (such as the suspension method of traditional pendulum tuned mass dampers), and can also adopt the same interlayer installation method as ordinary energy dissipators, so that the purpose of changing the structural inertia and tuning can be achieved more flexibly and effectively. In addition, it is found that the generated inertance coefficient can be much larger than its own physical mass, that is, inertance can adjust the inertia characteristics without basically changing the physical mass of the structure, and the increased inertia of inertance will not increase the inertial effect of the structure, so the lightweight design of the device can be realized, saving engineering costs and reducing the cost under the same control effect. This is another advantage of installing inertance in this device.

[0037] At the same time, the presence of the variable stiffness spring 8 and the magnetorheological damper 9 can not only improve the control effect and reduce the structural response, but also enable it to still generate a control effect through tuning when the stiffness or mass of the structure is reduced due to reasons such as the environment and material corrosion, alleviating to a certain extent the characteristics of the traditional pendulum tuned mass damper with a narrow control frequency band and being more sensitive to the change of the structural natural vibration frequency, and improving the robustness of the structure. At the same time, a limiter 6 is provided on the device, which is arranged at the end of the variable stiffness spring 8 through the spring limit seat 15. The spring limit seat 15 restricts the variable stiffness spring 8 to prevent the spring from sliding randomly during operation. After the spring installation is completed, it is in a pre-compressed state, and the pre-compression amount should be greater than the displacement amount of the additional mass block to improve the stability of the device.

[0038] Details not described in this invention are all well-known techniques to those skilled in the art.

[0039] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified and replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A variable stiffness magneto-fluid inertia adaptive damper for a fan structure, the variable stiffness magneto-fluid inertia adaptive damper is arranged in a tower (1), and is characterized in that: It includes a pendulum rope (2), a mass ball (3), an upper ball hinge (4), a sliding rod (5), a limiter (6), a stepping motor (7), a variable stiffness spring (8), a magnetorheological damper (9), and an inertance container (10). The top of the mass ball (3) is connected to the bottom of the pendulum rope (2), and the top of the pendulum rope (2) is connected to the top of the tower (1). An upper ball hinge (4) is provided at the bottom of the mass ball (3), and the upper ball hinge (4) is movably connected to the sliding rod (5). The bottom end of the sliding rod (5) passes through the inertance container (10), and the bottom end of the sliding rod (5) is connected to the bottom of the tower (1) through a lower swing rod (13). The variable stiffness spring (8), the magnetorheological damper (9), and the inertance container (10) are connected in parallel and arranged vertically. One end of the variable stiffness spring (8) is connected to the stepping motor (7), and the bottom of the stepping motor (7), the top of the magnetorheological damper (9), the bottom of the variable stiffness spring (8), and the bottom of the magnetorheological damper (9) are all connected to the limiter (6).

2. The variable-stiffness magneto-inertance adaptive damper for a fan structure according to claim 1, wherein: A foundation (12) is provided at the bottom of the tower (1), and a bearing platform (11) is provided on the upper surface of the foundation (12). The lower swing rod (13) connected to the bottom of the sliding rod (5) is connected to the bearing platform (11) through a lower ball hinge (14).

3. The variable-stiffness magnetorheological inertia adaptive damper for a fan structure according to claim 1, characterized in that: The limiter (6) located above is welded to the sliding rod (5).

4. The variable stiffness magneto-inertia-capacitance adaptive damper for a fan structure according to claim 1, wherein: A spring limit seat (15) is further provided on the upper surface of the limiter (6) located below, and the bottom of the variable stiffness spring (8) is rotatably connected to the spring limit seat (15).

5. The variable-stiffness magnetorheological inertia adaptive damper for a fan structure according to claim 1, characterized in that: The number of the pendulum ropes (2) is at least two.

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