A wind turbine design method using friction-tuned mass damper

Abstract

The application relates to the technical field of wind power generation, and discloses a wind turbine design method adopting a frictional tuned mass damper, which adds a frictional tuned mass damper to a man platform in a tower drum of a wind turbine, establishes a motion equation of the wind turbine after adding the frictional tuned mass damper based on a structural dynamics principle, deduces a mathematical analytic expression of a system dynamic coefficient, and obtains parameters of the frictional tuned mass damper through a system optimization theory. The application solves the problems that the prior art is difficult to realize damping through the tuned mass damper in the narrow space in the cabin or the tower drum, and the damping control effect is poor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wind power generation, in particular to a wind turbine design method using frictional tuned mass damper. BACKGROUND

[0002] In recent years, wind power generation has been continuously concerned and developed in various countries due to the outstanding advantages of wind energy, such as renewable, non-polluting, widely distributed, and low cost. Megawatt wind turbines belong to high-soft long-period and low-damping structures. During long-term service, wind load and wave load will make the tower always in a small vibration state, which is easy to cause meshing failure of gear, transmission shaft and generator in the nacelle, and loosening and shearing of connecting bolts at the bottom of the tower, thereby reducing power generation efficiency. In addition, the action of hurricanes and earthquakes can cause severe tower vibration deformation, reduce its fatigue life, and even cause catastrophic accidents of the entire wind turbine. Therefore, how to control the vibration of the tower has become one of the key problems to be solved in the current wind power industry.

[0003] In the vibration control of high-rise structures, tuned mass damper (TMD) has been widely promoted and developed due to its simple structure, high stability, no need for external energy and low maintenance cost. When the wind turbine structure is subjected to external excitation, the vibration energy will be transferred to the TMD structure, so that the vibration energy of the structure is redistributed between the wind turbine structure and the TMD structure, achieving the purpose of reducing the vibration of the structure. Due to the special structure of the wind turbine structure, the conventional TMD often needs to be designed and installed in the nacelle or the tower, but the current TMD control tower vibration is only in the conceptual design stage, and the TMD technology has not yet applied to the engineering practice of wind turbine structure. The main reasons are as follows: firstly, the engine, transmission shaft and gear of the wind turbine are placed in the nacelle, and the small space in the nacelle is not enough to provide sufficient stroke for the TMD. On the other hand, the vibration control effect of TMD is positively correlated with the mass ratio, and the mass of TMD is often several tons under the mass ratio of 1~3%, which easily affects the material strength and static stability of the tower. Therefore, combined with the special structure of the wind turbine tower, it is of practical social background and engineering application value to develop a new damper suitable for vibration reduction of the wind turbine tower structure. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the present application provides a wind turbine design method using frictional tuned mass damper, which solves the problems of the prior art that it is difficult to use tuned mass damper to achieve vibration reduction in the small space inside the nacelle or tower, and poor vibration control effect.

[0005] The technical scheme adopted by the present application to solve the above problems is:

[0006] The application discloses a wind turbine design method adopting a frictional tuned mass damper, a frictional tuned mass damper is additionally arranged on a man platform in a tower drum of a wind turbine, a motion equation of the wind turbine after the frictional tuned mass damper is additionally arranged is established based on a structural dynamics principle, a mathematical analytic expression of a dynamic coefficient of the system is derived, and the parameters of the frictional tuned mass damper are obtained through a system optimization theory.

[0007] As a preferred technical scheme, the method comprises the following steps: S1, modifying and designing the frictional tuned mass damper according to the structure of the man platform in the tower drum of the wind turbine; the wind turbine comprises a tower drum, the man platform is arranged at intervals in the tower drum, and a keel steel frame is arranged at the bottom of the man platform; the keel steel frame at the bottom of the man platform in the tower drum is kept unchanged, and a layer of polytetrafluoroethylene plate is additionally arranged on the upper surface of the keel steel frame, and the polytetrafluoroethylene plate is provided with apertures as a ladder and a cable channel.

[0008] As a preferred technical scheme, the frictional tuned mass damper comprises a mass block for providing a reverse motion inertia force, a spring system for providing lateral stiffness, and a viscous liquid damper for dissipating energy, and the mass block, the spring system and the viscous liquid damper are connected respectively.

[0009] As a preferred technical scheme, the method comprises the following steps: S2, obtaining the dynamic parameters of the structural model of the wind turbine based on an energy method.

[0010] As a preferred technical scheme, step S2 comprises the following steps:

[0011] S21, simplifying the actual wind turbine structure into an equivalent single-degree-of-freedom system dynamics model according to a Rayleigh energy method; the wind turbine structure is simplified into a structure with a concentrated mass cantilever column at the top; taking a center point at the bottom of a tower drum of the wind turbine as an origin of a coordinate system, a vertical direction of the tower drum is taken as an z axis, a downwind direction of the wind turbine is taken as an x axis, a concentrated mass of a nacelle and blades at the top of the tower drum is taken as M , a total height of a hub of the tower drum is taken as H , a mass density of the tower drum in the vertical direction is taken as m ( z ), and a bending stiffness of the tower drum changing along the z axis is taken as EI ( z );

[0012] S22, obtaining the generalized mass, the damping, the stiffness and the equivalent load of the wind turbine by combining the generalized variational principle and the equivalent single-degree-of-freedom system dynamics model of the wind turbine in step S21, and the formula is as follows:

[0013] ;

[0014] In the formula,m s For the generalized mass of wind turbine units, c s For the generalized damping of wind turbine units c s For the generalized combined stiffness of wind turbine units, F eff ( t () represents the generalized equivalent load of the wind turbine unit. H The total height of the tower hub. z The vertical coordinates of the tower are... dz Let the integral of the micro-end length along the height of the tower be the length of the micro-end. p ( z , t ( ) represents the distributed load along the height of the tower. F (t) represents the concentrated load at the top of the tower. t For time, EI ( z ) along the tower z Unit bending stiffness varying along the axial direction M The total mass of the nacelle and blades at the top of the tower. m ( z ( ) represents the mass density of the tower along the vertical direction. φ(H) This represents the shape function value of the tower top. φ (H) The value is 1, where g is the acceleration due to gravity. c ( z ) along the tower z The unit damping coefficient varies along the axis, with the symbols ′ and ″ representing the first and second derivatives with respect to z, respectively. φ ( z ) represents the shape function of the tower in the vertical direction. φ ( z ) is represented as:

[0015] .

[0016] As a preferred technical solution, the following steps are included: S3, combining the dynamic parameters of the wind turbine structure, the parameter design of the friction-type tuned mass damper is carried out; the parameters to be designed include the mass of the friction-type tuned mass damper, the optimal frequency ratio of the friction-type tuned mass damper, the stiffness of the spring in the friction-type tuned mass damper, and the damping coefficient of the viscous liquid damper in the friction-type tuned mass damper.

[0017] As a preferred technical solution, step S3 includes the following steps:

[0018] S31, Design mass of friction-type tuned mass damper:

[0019] ;

[0020] wherein, m d is the mass of the friction type tuned mass damper, a is an intermediate parameter, a the value range of is 1%~3%.

[0021] 1. A wind turbine design method using a friction tuned mass damper, characterized in that step S3 comprises the following steps:

[0022] S32, designing the optimal frequency ratio of the friction type tuned mass damper, the calculation formula is:

[0023] ;

[0024] wherein,

[0025] ;

[0026] wherein, μ opt is the optimal frequency ratio of the friction type tuned mass damper, α is the stiffness tuning parameter one, γ is the stiffness tuning parameter two, λ is the stiffness tuning parameter three, κ is the stiffness tuning parameter four, χ is the mass tuning parameter, χ=( P 0-2 f μ ) / P 0, P 0 is the load amplitude, f μ is the sliding friction force between the friction type tuned mass damper and the polytetrafluoroethylene plate;

[0027] k 11 、 k 12 , k 22 are the stiffness coefficients of the wind turbine with the FTMD system, φ FT is the shape function value at the friction type tuned mass damper.

[0028] As a preferred technical solution, step S3 comprises the following steps:

[0029] S33: Design the stiffness of the spring in the friction type tuned mass damper device:

[0030] ;

[0031] wherein, This indicates the stiffness of the spring in a friction-type tuned mass damper device.

[0032] As a preferred technical solution, step S3 includes the following steps:

[0033] S34, Design the damping coefficient of the viscous liquid damper in a friction-type tuned mass damper:

[0034] ;

[0035] in, c opt This represents the damping coefficient of the viscous fluid damper in a friction-type tuned mass damper. m d Indicates the quality of FTMD. ω s This indicates the fundamental frequency of the wind turbine. μ opt This indicates the optimal frequency ratio. α For stiffness tuning parameter one, λ For stiffness tuning parameter three, κ For stiffness tuning parameter four, m s The generalized mass of wind turbine units β L This is the ratio of the frequency of the wind turbine to that of the FTMD.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] (1) The present invention practically combines the internal structure of the tower and develops a wind turbine design method using a friction tuned mass damper. The friction tuned mass damper (FTMD) based on the modified platform inside the wind turbine tower does not occupy extra space inside the wind turbine and does not affect the normal use function of the wind turbine; moreover, it does not introduce too much additional mass and does not affect the strength and static stability of the tower material.

[0038] (2) The novel friction-type tuned mass damper (FTMD) used in this invention can perform dual functions: First, when it is in operation, it can reduce the excessive vibration of the tower induced by wind load, earthquake, etc., and increase the fatigue life of the wind turbine itself; Second, when the viscous damper is locked, it can serve as a maintenance and temporary support platform.

[0039] (3) This invention will enrich and innovate the vibration control technology and equipment for wind turbine towers, provide technical support for ensuring the safe and efficient operation of wind turbines during their service life, and have significant practical engineering significance for the layout and development of wind energy and other related industries in my country. Attached Figure Description

[0040] Figure 1 This is an overall installation diagram of the novel friction-type tuned mass damper based on the modification of the platform inside the wind turbine tower involved in this invention;

[0041] Figure 2 This is a mechanical analysis model diagram of the wind turbine unit equipped with a novel friction-type tuned mass damper (FTMD) mentioned in this invention;

[0042] Figure 3 This is a schematic diagram of the polytetrafluoroethylene support plate of the FTMD in an embodiment of the present invention;

[0043] Figure 4 This is an overall view of the keel steel frame in an embodiment of the present invention;

[0044] Figure 5 This is a cross-sectional layout diagram of the keel steel frame in an embodiment of the present invention.

[0045] The markings and their corresponding names in the attached diagram are as follows: 1—blade, 2—nacelle, 3—tower, 4—access platform, 5—foundation, 6—buffer rubber ring, 7—mass block, 8—PTFE plate, 9—viscous damper, 10—spring, 11—ladder and cable channel, 12—main beam, 13—secondary beam. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0047] Example 1

[0048] like Figures 1 to 5 As shown, the frustum-shaped tower, serving as the support structure for the wind turbine, is composed of several conical sections connected by flanges, with the diameter gradually decreasing from bottom to top, forming an overall frustum shape. Five to six access platforms 4 are spaced apart inside the tower for easy access and maintenance via ladders. Based on this, this invention, combined with the internal structure of the tower, develops a novel parameter design method and installation technology for a frictional tuned mass damper (FTMD) modified from a platform inside the wind turbine tower. The motion equations of the wind turbine after adding the FTMD are established based on structural dynamics principles, and the mathematical analytical expression for the system's dynamic coefficients is derived. The frequency ratio, stiffness, and damping ratio parameter design methods for the FTMD device are obtained through system optimization theory. Combined with device design optimization, an FTMD installation technology is developed. When the damper is in operation, it can control excessive vibration of the tower; when locked, it can serve as a maintenance platform. This invention will enrich and innovate the vibration control technology and equipment for wind turbine towers, providing technical support for ensuring the safe and efficient operation of wind turbines during their service life, and has significant practical engineering implications for the layout and development of wind energy and related industries in my country.

[0049] This invention, combining the internal structure of the wind turbine tower, develops a design method for wind turbines employing friction-tuned mass dampers (FTMDs). Based on structural dynamics principles, the motion equations of the wind turbine after FTMD installation are established, and the mathematical analytical expression for the system's dynamic coefficients is derived. Through system optimization theory, design methods for the frequency ratio, stiffness, and damping ratio parameters of the FTMD device are obtained. Combined with device design optimization, FTMD installation technology is developed. When in operation, the damper can control excessive vibration of the tower; when locked, it can serve as a maintenance platform. This method is simple and easy to implement, and its high reliability has been verified by examples and data, demonstrating promising application prospects and significant practical engineering implications for the layout and development of wind energy and related industries in my country.

[0050] To address the technical problems described in the background section, the present invention provides a wind turbine design method employing a friction-tuned mass damper, comprising the following steps:

[0051] Step 1: Based on the special structure of the platform inside the wind turbine tower, conduct the initial modification design of a new type of friction tuned mass damper;

[0052] Wind turbine units mainly consist of blades, hubs, nacelles, and towers, as shown in the attached diagram. Figure 1 As shown. The tower, as the supporting structure of the wind turbine, primarily functions to lift the rotor and nacelle to a certain height, thereby obtaining sufficient wind energy for power generation. The frustum-shaped tower is composed of several conical sections connected by flanges, with the diameter gradually decreasing from the bottom upwards, forming an overall frustum shape. The tower interior is equipped with 5-6 access platforms at intervals, facilitating ladder access and maintenance. (See attached image.) Figure 1 The novel friction-tuned mass damper (FTMD) is based on a modified tower internal platform. The original steel frame at the bottom of the tower internal platform remains unchanged, but a layer of polytetrafluoroethylene (PTFE) plate is added on top of the steel frame to reduce the sliding friction of the FTMD during movement. The PTFE plate has perforations to serve as a ladder and cable channel.

[0053] Figure 1 The novel friction-tuned mass damper (FTMD) consists of three parts: a mass block providing the inertial force of reverse motion, a spring system providing lateral stiffness, and a viscous liquid damper for energy dissipation. The mass block, placed in the middle of a PTFE plate, is connected to a rubber ring on the tower wall via four springs and four viscous liquid dampers. The FTMD has two main functions: First, when in operation, it reduces excessive tower vibration induced by wind loads, earthquakes, etc., increasing the fatigue life of the wind turbine itself. Second, when the viscous damper is locked, it can serve as a maintenance and temporary support platform.

[0054] Step 2: Obtain the dynamic parameters of the wind turbine structural model based on the energy method;

[0055] Step S21: Based on the Rayleigh energy method, the actual wind turbine structure is simplified into an equivalent single-degree-of-freedom system dynamic model. (See attached diagram.) Figure 2 As shown, the wind turbine structure is simplified to a cantilever column with concentrated mass at the top. Taking the center point of the top surface of foundation 3 as the origin of the coordinate system, the vertical direction of the tower is... z The shaft, the downwind direction of the wind turbine is x The concentrated mass of the shaft, the nacelle at the top of the tower, and the blades is M The total height of the tower hub is H Mass density in the vertical direction of the tower m ( z ), tower along z Bending stiffness varying in the axial direction EI ( z );

[0056] Step S22: Combining the generalized variational principle and the equivalent single-degree-of-freedom system dynamic model of the wind turbine in S21, the generalized mass, damping, stiffness, and equivalent load of the wind turbine can be obtained.

[0057] (1)

[0058] In equation (1), t Indicates time, t The unit is s. m s and k s These are generalized masses, with units of kg and N / m, respectively. EI ( z ) along the tower z Unit bending stiffness varying along the axial direction, in N / m 2 . M This refers to the total mass of the nacelle and blades at the top of the tower, expressed in kg. m ( z ) represents the mass density of the tower along the vertical direction, in kg / m³. φ(H) The shape function value of the tower top is 1. g represents the acceleration due to gravity, and its unit is m / s². 2 . c ( z ) along the tower z Damping coefficient per unit length varying along the axial direction, in N·s / m 2 The symbols ' and '' represent the first and second derivatives with respect to z, respectively. φ ( z Let be the shape function of the tower in the vertical direction, which can be expressed as:

[0059] (2)

[0060] In equation (1), H Indicates the total height of the tower hub. z The vertical coordinates of the tower are given.

[0061] Step 3: Based on the dynamic parameters of the wind turbine structure, design the parameters of the novel friction-type tuned mass damper (FTMD);

[0062] Step S31: Calculate the mass of the novel friction-tuned mass damper (FTMD). m d ;

[0063] (3)

[0064] In equation (3), a These are intermediate parameters. a The value range is 1% to 3%, quality m d The unit is kg;

[0065] Step S32, using the dynamic coefficient η Calculate the optimal frequency ratio of a novel friction-tuned mass damper (FTMD);

[0066] Based on the principles of structural dynamics and appendices Figure 2 A mechanical analysis model of a wind turbine equipped with a novel friction-tuned mass damper (FTMD) yields the following equations of motion:

[0067] (4)

[0068] In equation (4), f μ The sliding friction force between the FTMD and the PTFE sheet can be expressed as: f μ = μ F m d g . μ F The coefficient of friction of the polytetrafluoroethylene sheet is generally taken as 0.04. c 1 and c Both figures represent the damping coefficients of wind turbines equipped with FTMD systems. k 11 , k 12 k 22 These are the stiffness coefficients of the wind turbine with the FTMD system installed, and they can be expressed as:

[0069] (5)

[0070] In equation (5), φ FT The shape function value at the FTMD is calculated based on equation (2) according to the installation height of the FTMD.

[0071] According to the resonance balance method, the power coefficient of the wind turbine with FTMD system is obtained according to equation (4):

[0072] (6)

[0073] In equation (6), η is the dynamic coefficient of the system. μ The natural frequency of the FTMD under seismic excitation ω d ( ω d = k 22 / m d ) and the natural frequency of the wind turbine ω s ( ω s = k 11 / m s The ratio of ). β It is the ratio of the load frequency to the tower's natural frequency. ζ The damping tuning parameters of the FTMD can be expressed as follows: ζ = c d / ( m d ω s ), c d χ is the damping coefficient in a viscous fluid damper. χ is the mass tuning parameter, which can be expressed as χ=( P 0-2 f μ ) / P 0, P 0 represents the load amplitude. f μ This refers to the sliding friction force between the FTMD and the polytetrafluoroethylene sheet. α , γ , κ and λ These are all stiffness tuning parameters, which can be expressed as follows:

[0074] (7)

[0075] According to formula (6), the dynamic coefficient η The mathematical characteristics of the expression, when the dynamic coefficient does not depend on the damping coefficient c d hour ， The following mathematical relationship can be obtained:

[0076] (8)

[0077] By solving formula (8), the frequency ratio of the two branch resonance points of the system can be obtained as follows:

[0078] (9)

[0079] In equation (9), β The frequency ratio of the branch resonance points is given by the subscripts L and R, which represent the left and right branch resonance points, respectively.

[0080] Meanwhile, in formula (6) dynamic coefficient η In the expression, when the damping coefficient c d As the value approaches infinity, the following mathematical relationship can be obtained:

[0081] (10)

[0082] In equation (10), the subscripts L and R represent the left and right branch resonance points, respectively.

[0083] When the dynamic coefficients of the two branch resonance points are equal, the system can be tuned to its optimal state. Therefore, based on formula (10), we can obtain...

[0084] (11)

[0085] By combining equations (9) and (11), the optimal frequency ratio for FTMD can be obtained. μ opt The expression is as follows:

[0086] (12)

[0087] Step S33: Obtain the stiffness of the spring in the novel friction-type tuned mass damper (FTMD) device;

[0088] According to equations (5) and (12), the stiffness of the spring in the FTMD device is:

[0089] (13)

[0090] Step S34: Obtain the damping coefficient of the viscous liquid damper in the novel friction-type tuned mass damper (FTMD) device;

[0091] Since the amplitude of the dynamic coefficient is equal at the frequency ratio of the two branch resonance points, its slope is 0, meaning the first derivative of the dynamic coefficient with respect to the frequency ratio is zero. Therefore, we can obtain...

[0092] (14)

[0093] Combining equations (6), (8), and (12), we can obtain the damping coefficient of the viscous liquid damper in the FTMD device as follows:

[0094] (15)

[0095] Step 4: Select a friction-type tuned mass damper with the corresponding parameters and install it on the wind turbine tower platform;

[0096] As attached Figure 1 As shown, a novel friction-type tuned mass damper (FTMD4) based on the modification of an internal platform within a wind turbine tower is described. The wind turbine structure includes a tower 2 and a nacelle 2 mounted on top of the tower. Blades 1 are rotatably mounted on the nacelle 2. The tower 2 is composed of several sections connected sequentially via flanges. Five to six access platforms 4 are spaced apart inside the tower for easy access and maintenance via ladders. The novel friction-type tuned mass damper FTMD4, modified from the internal access platforms 4, requires a buffer rubber ring 5 around the tower wall to protect the tower. A mass block 6 is placed in the center of the tower and connected to the buffer rubber ring 5 on the tower wall via four springs 9 and four viscous liquid dampers 9. The mass block 6 generates a reverse inertial force, the springs 9 provide lateral stiffness, and the viscous liquid dampers 9 dissipate vibration energy. When the wind turbine structure is subjected to external excitation, the vibration energy is transferred to the FTMD structure, thereby redistributing the vibration energy between the wind turbine structure and the FTMD structure, achieving the goal of reducing structural vibration.

[0097] As attached Figure 3 As shown, the support plate of the FTMD is preferably a polytetrafluoroethylene plate 7 to reduce the sliding friction of the FTMD during movement. The polytetrafluoroethylene plate has pores to serve as ladders and cable channels 10.

[0098] As attached Figure 4 As shown, the polytetrafluoroethylene plate 7 is installed on the keel steel frame, which is welded together from three main beams 11 and five secondary beams 12.

[0099] As attached Figure 5 As shown, the main beam 11 of the keel steel frame is made of square steel pipe, and the secondary beam 12 is made of channel steel welded together.

[0100] The beneficial technical effects of this application are:

[0101] This invention practically integrates with the internal structure of the wind turbine tower to develop a design method for wind turbines employing friction-tuned mass dampers. The friction-tuned mass damper (FTMD) based on the modified platform inside the wind turbine tower does not occupy extra space inside the wind turbine and does not affect the normal operation of the wind turbine. Furthermore, it does not introduce excessive additional mass and does not affect the strength of the tower material or its static stability.

[0102] The novel friction-type tuned mass damper (FTMD) used in this invention has a dual function. First, when in operation, it can reduce excessive tower vibration induced by wind loads, earthquakes, etc., increasing the fatigue life of the wind turbine itself. Second, when the viscous damper 8 is in a locked state, it can serve as a maintenance and temporary support platform.

[0103] This invention will enrich and innovate the vibration control technology and equipment for wind turbine towers, providing technical support for ensuring the safe and efficient operation of wind turbines during their service life, and has significant practical engineering implications for the layout and development of wind energy and related industries in my country.

[0104] Example 2

[0105] like Figures 1 to 5 As shown, as a further optimization of Embodiment 1, this embodiment also includes the following technical features based on Embodiment 1:

[0106] This invention, combining the internal structure of the wind turbine tower, develops a design method for wind turbines employing friction-tuned mass dampers (FTMDs). Based on structural dynamics principles, the motion equations of the wind turbine after FTMD installation are established, and the mathematical analytical expression for the system's dynamic coefficients is derived. Through system optimization theory, design methods for the frequency ratio, stiffness, and damping ratio parameters of the FTMD device are obtained. Combined with device design optimization, FTMD installation technology is developed. When in operation, the damper can control excessive vibration of the tower; when locked, it can serve as a maintenance platform. This method is simple and easy to implement, and its high reliability has been verified by examples and data, demonstrating promising application prospects and significant practical engineering implications for the layout and development of wind energy and related industries in my country.

[0107] like Figure 1As shown, a novel friction-type tuned mass damper (FTMD) based on the modification of an internal platform within a wind turbine tower is described. The wind turbine structure includes a tower 3 and a nacelle 2 mounted on top of the tower. Blades 1 are rotatably mounted on the nacelle 2. The tower 3 is composed of several sections connected sequentially via flanges. Five to six access platforms 4 are spaced apart inside the tower for easy access and maintenance via ladders. The novel friction-type tuned mass damper FTMD, based on the internal platform 4 of the wind turbine tower, requires a buffer rubber ring 6 to protect the tower wall. A mass block 7 is placed in the center of the tower and connected to the rubber ring 6 on the tower wall via four springs 8 and four viscous liquid dampers 9. The mass block 7 generates a reverse inertial force, the springs 10 provide lateral stiffness, and the viscous liquid dampers 9 dissipate vibration energy. When the wind turbine structure is subjected to external excitation, the vibration energy is transferred to the FTMD structure, thereby redistributing the vibration energy between the wind turbine structure and the FTMD structure, achieving the purpose of reducing structural vibration.

[0108] like Figure 3 As shown, the support plate of the FTMD is preferably a polytetrafluoroethylene plate 8 to reduce the sliding friction of the FTMD during movement. The polytetrafluoroethylene plate has pores to serve as ladders and cable channels 11.

[0109] like Figure 4 As shown, the polytetrafluoroethylene sheet 8 is installed on the keel steel frame, which is welded together from three main beams 12 and five secondary beams 13.

[0110] like Figure 5 As shown, the main beam 12 of the keel steel frame is made of square steel pipe, and the secondary beam 13 is made of channel steel welded together.

[0111] The novel friction-type tuned mass damper installation technology and parameter design method based on the retrofit of the platform inside the wind turbine tower advocated in this invention have been verified by theoretical analysis and numerical simulation, which have also verified the rationality of the design method.

[0112] In summary, this invention provides a feasible design method for wind turbines using friction-tuned mass dampers, which will enrich and innovate wind turbine tower vibration control technology and equipment, provide technical support for ensuring the safe and efficient operation of wind turbines during their service life, and have significant practical engineering implications for the layout and development of wind energy and related industries in my country.

[0113] As described above, the present invention can be implemented well.

[0114] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0115] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A design method for a wind turbine generator using a friction-tuned mass damper, characterized in that, A friction-type tuned mass damper was installed on the access platform inside the wind turbine tower. Based on the principles of structural dynamics, the equation of motion for the wind turbine after the installation of the friction-type tuned mass damper was established. The mathematical analytical expression of the system's dynamic coefficients was derived. The parameters of the friction-type tuned mass damper were obtained through system optimization theory. The process includes the following steps: S1, Based on the structure of the access platform inside the wind turbine tower, the friction-type tuned mass damper was modified and designed: The wind turbine includes a tower, and access platforms are spaced apart inside the tower. The bottom of the access platform is equipped with a keel steel frame. Keeping the keel steel frame at the bottom of the access platform inside the tower unchanged, a layer of polytetrafluoroethylene (PTFE) plate is added to the upper surface of the keel steel frame. The PTFE plate has openings to serve as ladders and cable channels. S2, Based on the energy method, the dynamic parameters of the wind turbine structural model are obtained. Step S2 includes the following steps: S21, Based on the Rayleigh energy method, the actual wind turbine structure is simplified into an equivalent single-degree-of-freedom system dynamic model: the wind turbine structure is simplified to a cantilever column with concentrated mass at the top; the center point of the bottom of the wind turbine tower is taken as the origin of the coordinate system, and the vertical direction of the tower is... z The shaft, the downwind direction of the wind turbine is x The concentrated mass of the shaft, the top nacelle of the wind turbine tower, and the blades is M The total height of the tower hub is H Mass density in the vertical direction of the tower m ( z ), tower along z Bending stiffness varying in the axial direction EI ( z ); S22, combining the generalized variational principle and the equivalent single-degree-of-freedom system dynamic model of the wind turbine in step S21, obtain the generalized mass, damping, stiffness, and equivalent load of the wind turbine, as shown in the formulas: ； In the formula, m s For the generalized mass of wind turbine units, c s For the generalized damping of wind turbine units c s For the generalized combined stiffness of wind turbine units, F eff ( t () represents the generalized equivalent load of the wind turbine unit. H The total height of the tower hub. z The vertical coordinates of the tower are... dz Let the integral of the micro-end length along the height of the tower be the length of the micro-end. p ( z , t () represents the distributed load along the height of the tower. F (t) represents the concentrated load at the top of the tower. t For time, EI ( z ) along the tower z Unit bending stiffness varying along the axial direction M The total mass of the nacelle and blades at the top of the tower. m ( z () represents the mass density of the tower along the vertical direction. φ(H) This represents the shape function value of the tower top. φ(H) The value is 1, where g is the acceleration due to gravity. c ( z ) along the tower z The unit damping coefficient varies along the axis, with the symbols ′ and ″ representing the first and second derivatives with respect to z, respectively. φ ( z ) represents the shape function of the tower in the vertical direction. φ ( z ) is represented as: 。 2. The wind turbine design method using a friction-tuned mass damper according to claim 1, characterized in that, The friction-type tuned mass damper includes a mass block that provides the inertial force of the reverse motion, a spring system that provides lateral stiffness, and a viscous liquid damper that dissipates energy. The mass block is connected to the spring system and the viscous liquid damper, respectively.

3. The wind turbine design method using a friction-tuned mass damper according to claim 1, characterized in that, The process includes the following steps: S3, combining the dynamic parameters of the wind turbine structure, to design the parameters of the friction-type tuned mass damper; the parameters to be designed include the mass of the friction-type tuned mass damper, the optimal frequency ratio of the friction-type tuned mass damper, the stiffness of the spring in the friction-type tuned mass damper, and the damping coefficient of the viscous liquid damper in the friction-type tuned mass damper.

4. The wind turbine design method using a friction-tuned mass damper according to claim 3, characterized in that, Step S3 includes the following steps: S31, Design mass of friction-type tuned mass damper: ； In the formula, m d For the mass of a friction-type tuned mass damper, a These are intermediate parameters. a The value range is 1% to 3%.

5. A wind turbine design method using a friction-tuned mass damper according to claim 4, characterized in that, Step S3 includes the following steps: S32, the optimal frequency ratio for designing a friction-type tuned mass damper is calculated using the following formula: ； In the formula, ； in, μ opt This is the optimal frequency ratio for a friction-type tuned mass damper. α For stiffness tuning parameter one, γ For stiffness tuning parameter two, λ For stiffness tuning parameter three, κ Here, χ is the stiffness tuning parameter, and χ is the mass tuning parameter. χ = ( P 0-2 f μ ) / P 0, P 0 represents the load amplitude. f μ The sliding friction force between the friction-type tuned mass damper and the polytetrafluoroethylene plate; k 11 , k 12 k 22 The stiffness coefficients of wind turbine units equipped with FTMD systems are all related to the addition of FTMD systems. φ FT This represents the shape function value at the friction-type tuned mass damper.

6. The wind turbine design method using a friction-tuned mass damper according to claim 5, characterized in that, Step S3 includes the following steps: S33: Design the spring stiffness in a friction-type tuned mass damper device: ； In the formula, This indicates the stiffness of the spring in a friction-type tuned mass damper device.

7. A wind turbine design method using a friction-tuned mass damper according to claim 6, characterized in that, Step S3 includes the following steps: S34, Design the damping coefficient of the viscous liquid damper in a friction-type tuned mass damper: ； in, c opt This represents the damping coefficient of the viscous fluid damper in a friction-type tuned mass damper. m d Indicates the quality of FTMD. ω s This indicates the fundamental frequency of the wind turbine. μ opt Indicates the optimal frequency ratio. α For stiffness tuning parameter one, λ For stiffness tuning parameter three, κ For stiffness tuning parameter four, m s The generalized mass of wind turbine units β L This is the ratio of the frequency of the wind turbine to that of the FTMD.

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