Design and installation method of prestressed tuned mass dampers under wave or seismic loads

Abstract

The present invention discloses a method for designing and installing a prestressed tuned mass damper under wave or seismic loads, including the step of calculating the parameters of the prestressed tuned mass damper based on the material parameters and geometric parameters of the wind turbine and the dynamic parameters of the wind turbine tower structure. By adopting the above technical solution, the parameters of the prestressed tuned mass damper are calculated based on the parameters of the wind turbine through a series of calculations. Then, the corresponding prestressed tuned mass damper is selected based on the parameters and installed on the wind turbine tower. This method can overcome the problem that the tower of an ultra-high wind turbine on land is easily damaged by fatigue of the wind turbine set due to wave and seismic vibration, and the tower safety is difficult to ensure. It can also achieve reasonable, effective, economical, practical, safe and reliable control of the vibration of the wind turbine tower.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine vibration control, and in particular to a design and installation method of a prestressed tuned mass damper under wave or earthquake loads. Background Art

[0002] Wind turbines typically operate in relatively harsh environments. In addition to enduring environmental loads such as wind, waves, and earthquakes, rotor turbulence and gusts, wake vortices, wind shear, yaw rotation, and tower shadowing can all trigger tower resonance. Over long-term service, even small tower vibrations can damage equipment within the nacelle and, coupled with blade vibrations, exacerbate tower fatigue. Furthermore, excessive vibration can degrade wind turbine performance, leading to downtime and reduced power generation efficiency. Therefore, it is imperative to implement cost-effective, safe, and efficient technical solutions to address tower vibration.

[0003] Wind loads and other factors act as direct excitations on wind turbine structures, while waves and earthquake loads act as indirect excitations on wind turbine structures. Relevant studies have shown that the vibration characteristics of structures and the excitation effects of vibration control devices under direct and indirect excitations are different. As an important means of achieving structural vibration control, tuned mass damping technology has now developed into a mainstream technology for structural vibration control. As a passive tuned mass damper, the prestressed tuned mass damper can double-tune its own frequency to reduce the pendulum length and increase the horizontal reverse resonance control force. Therefore, the prestressed tuned mass damper is expected to become an effective technology and means for widespread application and vigorous promotion of research in the field of wind turbine vibration reduction in the future.

[0004] In recent years, numerous scholars and engineers have proposed various parameter design methods for wind turbine vibration reduction devices under direct excitation, such as wind loads. However, they have neglected the influence of indirect excitation, such as waves and seismic loads. Wind turbines are often located in disaster-prone areas, such as canyons, mountainous areas, and oceans. Therefore, considering wave and seismic loads is crucial for wind turbine vibration reduction.

[0005] Therefore, it is imperative to solve the above problems. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a design and installation method of a prestressed tuned mass damper under wave or earthquake loads.

[0007] The technical solution is as follows:

[0008] A method for designing and installing a prestressed tuned mass damper under wave or seismic loads is performed in the following steps:

[0009] S1. Obtaining material parameters and geometric parameters of the wind turbine generator, and calculating the dynamic parameters of the wind turbine tower structure based on the material parameters and geometric parameters of the wind turbine generator;

[0010] S2. Calculating parameters of the prestressed tuned mass damper based on material parameters and geometric parameters of the wind turbine and dynamic parameters of the wind turbine tower structure;

[0011] S3. Select a corresponding prestressed tuned mass damper and install the prestressed tuned mass damper on the wind turbine tower;

[0012] The wind turbine includes a tower and a nacelle mounted on top of the tower, the blades are rotatably mounted on the nacelle, and the tower is composed of several tower sections connected in sequence by flanges;

[0013] The prestressed tuned mass damper includes a mass block connected between the tower top and the flange closest to the tower top by prestressed cables, and a plurality of viscous dampers are arranged along the circumference of the mass block, with the two ends of each viscous damper being elastically supported between the outer wall of the mass block and the inner wall of the corresponding tower section;

[0014] The key point is that step S2 includes:

[0015] S21. Determine initial design parameters of the prestressed tuned mass damper based on geometric parameters of the wind turbine;

[0016] S22. Calculate the mass control tuning parameters, stiffness control tuning parameters, and damping control tuning parameters of the prestressed tuned mass damper based on the dynamic parameters of the wind turbine tower structure, and calculate the prestressed design parameters of the prestressed tuned mass damper based on the dynamic parameters of the wind turbine tower structure and the initial design parameters of the prestressed tuned mass damper.

[0017] S23. Calculate, based on the mass control tuning parameters, stiffness control tuning parameters, and damping control tuning parameters of the prestressed tuned mass damper, the optimal frequency ratio of the wind turbine tower structure after the prestressed tuned mass damper is installed, as well as the frequency ratio of two branch resonance points and the dynamic coefficient amplitude of the prestressed tuned mass damper;

[0018] S24. Calculate the damper coefficient of the viscous damper in the prestressed tuned mass damper based on the optimal frequency ratio after the prestressed tuned mass damper is installed on the wind turbine tower structure, the frequency ratio of the two branch resonance points of the prestressed tuned mass damper, and the stiffness control tuning parameters.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The design and installation method of a prestressed tuned mass damper under wave or seismic loads using the above technical solution is based on the parameters of the wind turbine. After a series of calculations, the parameters of the prestressed tuned mass damper are obtained. Then, according to the parameters, the corresponding prestressed tuned mass damper is selected and installed on the wind turbine tower. This can overcome the problem that the tower of an ultra-high wind turbine on land is easily damaged by fatigue of the wind turbine due to wave and seismic vibration, and the safety of the tower is difficult to ensure, and realize reasonable, effective, economical, practical, safe and reliable control of the vibration of the wind turbine tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the structure of a wind turbine equipped with a prestressed tuned mass damper;

[0022] Figure 2 Schematic diagram of the dynamic model of a wind turbine tower structure equipped with a prestressed tuned mass damper and subjected to wave or seismic loads. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0024] like Figure 1 and Figure 2 As shown, a design and installation method for a prestressed tuned mass damper under wave or seismic loads is carried out in the following steps:

[0025] S1. Obtain material parameters and geometric parameters of the wind turbine generator, and calculate the dynamic parameters of the wind turbine tower structure based on the material parameters and geometric parameters of the wind turbine generator.

[0026] Specifically, in step S1, the dynamic parameters of the wind turbine tower structure include the generalized mass m of the tower s and generalized stiffness k s , generalized mass m s The unit is kg, the generalized stiffness k s The unit is N / m, generalized mass m s and generalized stiffness k s Calculate according to the following formula:

[0027]

[0028] In formula (1), z represents the coordinate of the tower height direction, m(z) represents the distributed mass of the tower, the unit of m(z) is kg / m, M represents the mass of the nacelle and blades, the unit of M is kg, Represents the vibration mode of the tower, H represents the total height of the tower, the unit of H is m, E represents the elastic model of the material of the wind turbine, I(z) represents the moment of inertia of the tower section, EI(z) represents the bending stiffness of the tower section, Represents the vibration mode value of the tower top.

[0029] The wind turbine comprises a tower 1 and a nacelle 2 mounted on top of the tower. Blades 3 are rotatably mounted on the nacelle 2. The tower 1 is composed of several tower segments 1a connected in sequence by flanges 5. The prestressed tuned mass damper 4 includes a mass block 4b connected by prestressed cables 4a between the tower top (i.e., the nacelle 2) and the flange 5 closest to the tower top. Several viscous dampers 4c are arranged along the circumference of the mass block 4b. The two ends of each viscous damper 4c are elastically supported between the outer wall of the mass block 4b and the inner wall of the corresponding tower segment 1a.

[0030] The mass block 4b is connected to the tower section 1a through several viscous dampers 4c that divide the circumference equally. The inertial force generated by the mass block 4b is used to dissipate energy, and the frequency of the mass block 4b itself is doubly tuned by prestressing and suspension height. In a service environment, when the horizontal amplitude of the top of the tower 1 is small, the mass block 4b will quickly generate corresponding horizontal vibrations under the action of the inertial force. Under the action of the prestressed cables, the inertial force generated by the movement of the mass block 4b will react on the structure itself, thereby producing a vibration reduction effect.

[0031] Furthermore, the viscous dampers 4c preferably adopt viscous liquid dampers. The viscous liquid dampers are passive vibration dampers filled with viscous damping liquid. They are energy-absorbing damping devices. They not only have the advantages of small size, no initial stiffness, reusability after earthquake, and stable vibration reduction effect, but are also suitable for the vibration reduction needs of working conditions such as earthquakes, typhoons, and mechanical vibrations. They can also provide stable and reliable additional damping, and can play a guiding and limiting role. They can also be used as composite vibration reduction elements to avoid frequency imbalance problems caused by large swing angles, thereby realizing the dual tuning function of the annular mass block under large vibrations.

[0032] S2. Calculate the parameters of the prestressed tuned mass damper according to the material parameters and geometric parameters of the wind turbine and the dynamic parameters of the wind turbine tower structure.

[0033] Specifically, step S2 includes:

[0034] S21. Determine initial design parameters of the prestressed tuned mass damper based on geometric parameters of the wind turbine.

[0035] In step S21, the initial design parameters of the prestressed tuned mass damper include the mass m of the prestressed tuned mass damper d (in kg) and the suspension height h of the prestressed tuned mass damper L (unit is m), which are respectively expressed as:

[0036]

[0037] In formula (2), h F Indicates the distance between the tower top and the flange closest to the tower top, in meters.

[0038] S22. Based on the dynamic parameters of the wind turbine tower structure, the mass control tuning parameters, stiffness control tuning parameters and damping control tuning parameters of the prestressed tuned mass damper are calculated, and the prestressed design parameters of the prestressed tuned mass damper are calculated in combination with the dynamic parameters of the wind turbine tower structure and the initial design parameters of the prestressed tuned mass damper.

[0039] In step S22, the mass control tuning parameters of the prestressed tuned mass damper are calculated based on the dynamic parameters of the wind turbine tower structure:

[0040] χ=(m s +m d ) / m s (3)

[0041] In formula (3), χ represents the mass control tuning parameter of the prestressed tuned mass damper;

[0042] Combining the dynamic parameters of the wind turbine tower structure and the initial design parameters of the prestressed tuned mass damper, the prestressed design parameters of the prestressed tuned mass damper are calculated according to the following formula:

[0043]

[0044] In formula (4), is the vibration mode value of the tower at the location where the prestressed tuned mass damper is installed, k 11 、k 12 and k 22 The three stiffness elements after adding a prestressed tuned mass damper to the wind turbine tower structure are expressed as follows:

[0045]

[0046] In formula (5), g represents the acceleration of gravity, f represents the prestress value of the prestressed cable in the prestressed tuned mass damper (unit: N), and the prestress value f of the prestressed cable in the prestressed tuned mass damper is the prestress design parameter of the prestressed tuned mass damper;

[0047] According to the dynamic parameters of the wind turbine tower structure, the stiffness control tuning parameters of the prestressed tuned mass damper are calculated:

[0048]

[0049] In formula (6), α, γ, λ, and K are the stiffness control tuning parameters of the prestressed tuned mass damper;

[0050] According to the dynamic parameters of the wind turbine tower structure, the damping control tuning parameters of the prestressed tuned mass damper are calculated:

[0051]

[0052] In formula (7), ζ is the damping tuning parameter of the prestressed tuned mass damper, c d is the damping coefficient of the viscous damper in the prestressed tuned mass damper, ω s The natural frequency of the wind turbine tower structure (in rad / s).

[0053] S23. Based on the mass control tuning parameters, stiffness control tuning parameters and damping control tuning parameters of the prestressed tuned mass damper, calculate the optimal frequency ratio after the prestressed tuned mass damper is installed on the wind turbine tower structure, as well as the frequency ratio of the two branch resonance points and the dynamic coefficient amplitude of the prestressed tuned mass damper.

[0054] In step S23, the optimal frequency ratio of the wind turbine tower structure after the prestressed tuned mass damper is installed is calculated based on the mass control tuning parameters, stiffness control tuning parameters, and damping control tuning parameters of the prestressed tuned mass damper:

[0055]

[0056] In formula (8), μ opt It represents the optimal frequency ratio after the wind turbine tower structure is equipped with a prestressed tuned mass damper;

[0057] According to the mass control tuning parameters, stiffness control tuning parameters and damping control tuning parameters of the prestressed tuned mass damper, the frequency ratio of the two branch resonance points of the prestressed tuned mass damper is calculated:

[0058]

[0059] In formula (9), β L and β R They represent the frequency ratios of the two branch resonance points of the prestressed tuned mass damper. It should also be noted that after the prestressed tuned mass damper is installed on the wind turbine tower structure, the previous single-degree-of-freedom system is transformed into a two-degree-of-freedom system. Previously, a single-degree-of-freedom system would resonate at its natural frequency (called a resonance point). After becoming a two-degree-of-freedom system, there are two resonance points, which are called branch resonance points. The ratio of the two branch resonance points to the natural frequency of the wind turbine tower structure is called the branch resonance point frequency ratio.

[0060] According to the mass control tuning parameters, stiffness control tuning parameters and damping control tuning parameters of the prestressed tuned mass damper, the dynamic coefficient amplitude of the prestressed tuned mass damper is calculated as follows:

[0061]

[0062] In formula (10), η max Represents the dynamic coefficient amplitude of the prestressed tuned mass damper.

[0063] S24. Calculate the damper coefficient of the viscous damper in the prestressed tuned mass damper based on the optimal frequency ratio after the prestressed tuned mass damper is installed on the wind turbine tower structure, the frequency ratio of the two branch resonance points of the prestressed tuned mass damper, and the stiffness control tuning parameters.

[0064] In step S24, the damper coefficient of the viscous damper in the prestressed tuned mass damper is calculated based on the optimal frequency ratio after the prestressed tuned mass damper is installed on the wind turbine tower structure, the frequency ratio of the two branch resonance points of the prestressed tuned mass damper, and the stiffness control tuning parameter:

[0065]

[0066] In formula (11), c opt Represents the damper coefficient of the viscous damper in a prestressed tuned mass damper.

[0067] S3. Select a corresponding prestressed tuned mass damper and install the prestressed tuned mass damper on the wind turbine tower.

[0068] Specifically, the mass m of the prestressed tuned mass damper is determined d , suspension height h L , the distance h between the tower top and the flange closest to the tower top F , mass control tuning parameter χ, stiffness control tuning parameter α, stiffness control tuning parameter γ, stiffness control tuning parameter λ, stiffness control tuning parameter K, damping tuning parameter ζ, prestress value f of prestressed cable, frequency ratio of two branch resonance points β L and β R , dynamic coefficient amplitude η max , the optimal frequency ratio μ after the wind turbine tower structure is equipped with a prestressed tuned mass damper opt , the damper coefficient c of the viscous damper in the prestressed tuned mass damper opt According to the above parameters, the corresponding prestressed tuned mass damper is selected and finally installed on the wind turbine tower, which can achieve an excellent shock absorption effect on the wind turbine tower structure.

[0069] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, ordinary technicians in this field can make various similar expressions without violating the purpose and claims of the present invention. Such changes fall within the scope of protection of the present invention.

Claims

1. A method for designing and installing a prestressed tuned mass damper under wave or seismic loads is carried out in the following steps: S1. Obtaining material parameters and geometric parameters of the wind turbine generator, and calculating the dynamic parameters of the wind turbine tower structure based on the material parameters and geometric parameters of the wind turbine generator; S2. Calculating parameters of the prestressed tuned mass damper based on material parameters and geometric parameters of the wind turbine and dynamic parameters of the wind turbine tower structure; S3. Select a corresponding prestressed tuned mass damper and install the prestressed tuned mass damper on the wind turbine tower; in, The wind turbine comprises a tower and a nacelle mounted on top of the tower, wherein the blades are rotatably mounted on the nacelle, and the tower is composed of a plurality of tower sections connected in sequence by flanges; The prestressed tuned mass damper includes a mass block connected between the tower top and the flange closest to the tower top by prestressed cables, and a plurality of viscous dampers are arranged along the circumference of the mass block, with the two ends of each viscous damper being elastically supported between the outer wall of the mass block and the inner wall of the corresponding tower section; It is characterized in that the step S2 includes: S21. Determine initial design parameters of the prestressed tuned mass damper based on geometric parameters of the wind turbine; S22. Calculate the mass control tuning parameters, stiffness control tuning parameters, and damping control tuning parameters of the prestressed tuned mass damper based on the dynamic parameters of the wind turbine tower structure, and calculate the prestressed design parameters of the prestressed tuned mass damper based on the dynamic parameters of the wind turbine tower structure and the initial design parameters of the prestressed tuned mass damper. S23. Calculate, based on the mass control tuning parameters, stiffness control tuning parameters, and damping control tuning parameters of the prestressed tuned mass damper, the optimal frequency ratio of the wind turbine tower structure after the prestressed tuned mass damper is installed, as well as the frequency ratio of two branch resonance points and the dynamic coefficient amplitude of the prestressed tuned mass damper; S24. Calculate the damper coefficient of the viscous damper in the prestressed tuned mass damper based on the optimal frequency ratio after the prestressed tuned mass damper is installed in the wind turbine tower structure, the frequency ratio of the two branch resonance points of the prestressed tuned mass damper, and the stiffness control tuning parameter; In step S24, the damper coefficient of the viscous damper in the prestressed tuned mass damper is calculated based on the optimal frequency ratio after the prestressed tuned mass damper is installed on the wind turbine tower structure, the frequency ratio of the two branch resonance points of the prestressed tuned mass damper, and the stiffness control tuning parameter: In formula (11), c opt represents the damper coefficient of the viscous damper in the prestressed tuned mass damper, m d represents the mass of the prestressed tuned mass damper, ω s represents the natural frequency of the wind turbine tower structure, ζ is the damping tuning parameter of the prestressed tuned mass damper, μ opt represents the optimal frequency ratio of the wind turbine tower structure after the prestressed tuned mass damper is installed, m s represents the generalized mass of the tower, α, λ, and K are the stiffness control tuning parameters of the prestressed tuned mass damper, and β L It represents the frequency ratio of one branch resonance point of the prestressed tuned mass damper.

2. The design and installation method of a prestressed tuned mass damper under wave or earthquake loads according to claim 1 is characterized in that: In step S1, the dynamic parameters of the wind turbine tower structure include the generalized mass m of the tower. s and generalized stiffness k s , calculated according to the following formula: In formula (1), z represents the coordinate of the tower height direction, m(z) represents the distributed mass of the tower, M represents the mass of the nacelle and blades, Represents the vibration mode of the tower, H represents the total height of the tower, E represents the elastic model of the material of the wind turbine, I(z) represents the moment of inertia of the tower section, Represents the vibration mode value of the tower top.

3. The design and installation method of a prestressed tuned mass damper under wave or earthquake loads according to claim 2, characterized in that: In step S21, the initial design parameters of the prestressed tuned mass damper include the mass m of the prestressed tuned mass damper. d and the suspension height h of the prestressed tuned mass damper L , which are respectively expressed as: In formula (2), h F Indicates the distance between the tower top and the flange closest to the tower top.

4. The design and installation method of a prestressed tuned mass damper under wave or earthquake loads according to claim 3 is characterized in that: In step S22, the mass control tuning parameters of the prestressed tuned mass damper are calculated based on the dynamic parameters of the wind turbine tower structure: χ=(m s +m d ) / m s (3) In formula (3), χ represents the mass control tuning parameter of the prestressed tuned mass damper; Combining the dynamic parameters of the wind turbine tower structure and the initial design parameters of the prestressed tuned mass damper, the prestressed design parameters of the prestressed tuned mass damper are calculated according to the following formula: In formula (4), is the vibration mode value of the tower at the location where the prestressed tuned mass damper is installed, k 11 、k 12 and k 22 The three stiffness elements after adding a prestressed tuned mass damper to the wind turbine tower structure are expressed as follows: In formula (5), g represents the acceleration of gravity, f represents the prestress value of the prestressed cable in the prestressed tuned mass damper, and the prestress value f of the prestressed cable in the prestressed tuned mass damper is the prestress design parameter of the prestressed tuned mass damper; According to the dynamic parameters of the wind turbine tower structure, the stiffness control tuning parameters of the prestressed tuned mass damper are calculated: In formula (6), γ is the stiffness control tuning parameter of the prestressed tuned mass damper; According to the dynamic parameters of the wind turbine tower structure, the damping control tuning parameters of the prestressed tuned mass damper are calculated: In formula (7), c d is the damping coefficient of the viscous damper in the prestressed tuned mass damper.

5. The design and installation method of a prestressed tuned mass damper under wave or earthquake loads according to claim 4, characterized in that: In step S23, the optimal frequency ratio of the wind turbine tower structure after the prestressed tuned mass damper is installed is calculated based on the mass control tuning parameter, stiffness control tuning parameter and damping control tuning parameter of the prestressed tuned mass damper: According to the mass control tuning parameters, stiffness control tuning parameters and damping control tuning parameters of the prestressed tuned mass damper, the frequency ratio of the two branch resonance points of the prestressed tuned mass damper is calculated: In formula (9), β R It represents the frequency ratio of another branch resonance point of the prestressed tuned mass damper; According to the mass control tuning parameters, stiffness control tuning parameters and damping control tuning parameters of the prestressed tuned mass damper, the dynamic coefficient amplitude of the prestressed tuned mass damper is calculated as follows: In formula (10), η max Represents the dynamic coefficient amplitude of the prestressed tuned mass damper.

6. The design and installation method of a prestressed tuned mass damper under wave or earthquake loads according to claim 1, characterized in that: The viscous damper is a viscous liquid damper.

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