Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03D—WIND MOTORS
  • F03D7/00—Controlling wind motors 
  • F03D7/02—Controlling wind motors  the wind motors having rotation axis substantially parallel to the air flow entering the rotor
  • F03D7/0298—Controlling wind motors  the wind motors having rotation axis substantially parallel to the air flow entering the rotor to prevent, counteract or reduce vibrations
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03D—WIND MOTORS
  • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
  • F03D13/20—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
  • F03D13/25—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors specially adapted for offshore installation
  • F03D13/256—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors specially adapted for offshore installation on a floating support, i.e. floating wind motors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03D—WIND MOTORS
  • F03D80/00—Details, components or accessories not provided for in groups F03D1/00 - F03D17/00
  • F03D80/80—Arrangement of components within nacelles or towers
  • F03D80/88—Arrangement of components within nacelles or towers of mechanical components
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/10—Vibration-dampers; Shock-absorbers using inertia effect
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/10—Vibration-dampers; Shock-absorbers using inertia effect
  • F16F7/104—Vibration-dampers; Shock-absorbers using inertia effect the inertia member being resiliently mounted
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
  • F05B2260/00—Function
  • F05B2260/96—Preventing, counteracting or reducing vibration or noise
  • F05B2260/964—Preventing, counteracting or reducing vibration or noise by damping means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F2228/00—Functional characteristics, e.g. variability, frequency-dependence
  • F16F2228/001—Specific functional characteristics in numerical form or in the form of equations
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/70—Wind energy
  • Y02E10/72—Wind turbines with rotation axis in wind direction

Definitions

• the present disclosure relates to a floating wind turbine comprising a vibration control system.
• Floating wind turbines are composed of slender and deformable structures operating in harsh environments combining waves, currents and turbulent winds. During the operation of a floating wind turbine, the latter may vibrate under the excitation of the environmental loads. The vibrations are transmitted in the floating foundation and mooring lines, increasing the overall ultimate loads and fatigue cycling.
• the structures are dimensioned to verify several criteria; one of which being that the natural frequencies of the structure may be at a sufficient distance from the frequency content of the environmental loads.
• nonlinear energy sinks also include drawbacks; one of which being the existence of detached resonance frequencies with high amplitude vibrations that can potentially be dangerous for the system to be controlled and must therefore be avoided.
• the present disclosure aims at improving the prior art.
• an aim of the present disclosure is to enable passive vibration control of a floating wind turbine.
• Another aim of the present disclosure is enabling damping of vibrations of a floating wind turbine caused by external loads without incurring detached resonance.
• a floating wind turbine comprising a mast, a nacelle and a plurality of rotating blades, the floating wind turbine being subjected to vibrations, and further comprising a vibration control system, characterized in that the vibration control system comprises a nonlinear energy sink, comprising a movable mass and a coupling device connecting the mass to a wall of the floating wind turbine, the coupling device having non-linear stiffness when biased in a direction perpendicular to the axis of the mast and being configured to perform non-linear viscous damping of a motion of the mass perpendicular to the axis of the mast.
• the movable mass is positioned inside the mast or the nacelle of the turbine.
• the vibration control system is further configured to maintain the motion of the mass within a plane perpendicular to the axis of the mast.
• the vibration control system comprises a slide link connecting the mass to a wall of the turbine, the slide link extending perpendicular to the axis of the mast and being rotatable about the axis of the mast.
• the mass is positioned within the mast of the turbine and the coupling device comprises at least one linear spring-dashpot extending transversally to the direction of motion of the mass.
• the linear spring-dashpot may comprise one end connected to the mass and another end suspended to a wall of the mast.
• the linear spring-dashpot spring-dashpot is mounted on the mast by a ball-joint connection.
• the vibration control system is further configured to apply linear stiffness and damping of a motion of the mass perpendicular to the axis of the mast.
• the vibration control device comprises a linear spring-dashpot extending perpendicular to the axis of the mast, and movable in rotation relative to the axis of the mast.
• the linear spring-dashpot’s stroke may further be dimensioned to prevent the motion of the mass from reaching a wall of the turbine.
• the vibration control device comprises an intermediate structure including:
• the vibration control device further comprises an additional damper having non-linear stiffness and configured to perform non-linear viscous damping of the motion of the intermediate structure.
• the mass is positioned within the mast of the turbine, and the coupling device comprises two linear spring-dashpots connecting two opposite ends of the mass to the mast of the turbine.
• the mass may be connected to each linear spring-dashpot by a respective ball-joint connection, and the mass is asymmetric with respect to an axis formed by the two ball-joint connections.
• the mass is positioned within the nacelle of the turbine, said nacelle being rotative relative the mast, and the coupling device comprises a first linear spring-dashpot extending perpendicular to the axis of the mast, and the vibration control device further comprises a second linear spring-dashpot extending parallel to the direction of the nacelle and connecting the mass to a wall of the nacelle.
• the floating wind turbine disclosed above in which the vibration control system comprises a nonlinear viscous damping term in addition to a nonlinear stiffness, allows to damp the vibrations of the turbine and to remove any detached resonance.
• the vibration control system is passive and may be integrated in the mast or in the nacelle of the turbine.
• this solution allows the weight of the shock absorbed to be reduced to up to 1% of the mass of the wind turbine to be damped.
• Figure 1a schematically represents a front face of a floating wind turbine
• Figure 1 b schematically represents a side face of a floating wind turbine
• Figure 2 schematically represents a first example of a non-linear energy sink integrated in the mast of a floating wind turbine, shown in a lateral view
• Figure 3 schematically represents a second example of a non-linear energy sink integrated in the mast of a floating wind turbine, shown in a lateral view
• Figure 4 schematically represents a third example of a non-linear energy sink integrated in the mast of a floating wind turbine, shown in a lateral view
• Figure 5 schematically represents an example of a non-linear energy sink integrated in the nacelle of a floating wind turbine, shown in a lateral view
• Figure 6 schematically represents a fourth example of a non-linear energy sink integrated in the mast of a floating wind turbine, shown in a top view
• Figure 7 schematically represents a fifth example of a non-linear energy sink integrated in the mast of a floating wind turbine, shown in a lateral view
• Figure 8 represents the performance in vibration control obtained in a floating wind turbine according to a numerical simulation.
• the floating wind turbine 1 comprises a mast 10 which may be generally rectilinear and extend along an axis X-X.
• the floating wind turbine also comprises a nacelle 11 , mounted on top of the mast 10 and extending along an axis Y-Y, which is perpendicular to the axis of the mast.
• the nacelle 11 may however be rotatably mounted to the mast about the axis X-X of the mast, in order to be orientable according to the direction of the wind.
• the floating wind turbine further comprises a rotor 12, rotatably mounted on an end of the nacelle 11.
• the rotor 12 comprises a plurality of blades, for instance three blades 13. Each blade may be pivotably mounted around its respective axis.
• the nacelle 11 typically includes an electrical generator, and mechanical and electrical transmission means (not shown).
• the floating wind turbine 1 may further comprise a floating support structure 14 on which the mast 10 is mounted, the floating support structure 14 being configured to ensure buoyancy and stability to the floating wind turbine.
• the floating support structure 14 may comprise one or several floating elements, which may be connected together for increased stability.
• the floating support structure may further be anchored to the water floor by one or more anchoring lines 15.
• the floating wind turbine may be subjected to various loads, including environmental loads such as waves, wind and currents, aero-structure interaction loads (for instance due to the blades passing by the mast) and mechanical loads related to inertia and control. These loads induce vibrations on the mast and hence the floating wind turbine may be described as a linear mass-spring-damper system.
• the floating wind turbine 1 further comprises a vibration control system 20 comprising a nonlinear energy sink 21 comprising a movable mass 210, and a coupling device 211 connecting the movable mass 210 to a wall of the floating wind turbine, the coupling device 211 having non-linear stiffness when biased in a direction perpendicular to the axis X-X of the mast, and being configured to perform non-linear viscous damping of a motion of the mass 210 perpendicular to the axis of the mast.
• the vibration control system and in particular the movable mass 210, may be positioned in the mast 10 of the turbine 1.
• the coupling device 211 connects the mass 210 to a wall 101 of the mast.
• the movable mass 210 is positioned in the mast 10, it is preferably positioned nearby an upper end of the mast, as the upper end of the mast is the portion undergoing the most important vibrations and hence the impact of the NES may be more important.
• the vibration control system and in particular the movable mass 210, may be positioned in the nacelle 11 of the turbine.
• the coupling device connects the mass 21 to a wall 111 of the nacelle 11 .
• the nonlinear stiffness and nonlinear viscous damping of the motion of the mast may be obtained using at least one linear spring-dashpot spring-dashpot which extends transversely to the motion of the mass and is therefore biased transversely by the motion of the mast.
• a linear spring-dashpot spring-dashpot exhibits linear stiffness and performs linear damping when biased in a direction parallel to the direction along which it extends, but exhibits nonlinear stiffness and performs nonlinear damping when biased transversely.
• linear spring-dashpot is meant a system comprising a linear spring and a linear dashpot, possibly integrated in a single device. It is therefore a system which provides both linear stiffness and linear viscous damping.
• the movable mass 210 may be positioned within the mast 10 of the turbine and the coupling device 211 may comprise at least one linear spring-dashpot 212 extending transversally to the motion of the mass. This may be achieved for example by suspending a linear spring-dashpot, having a lower end connected to the mass, and an upper end connected to a wall 101 of the mast 10 at an anchoring position which is located above a position of equilibrium of the mass when the floating wind turbine is in a static, vertical position. In that position, the linear spring-dashpot 212 may thus extend parallel to the axis of the mast, or along a direction that forms an angle below 45°, preferably 30°, with said axis.
• the suspended linear spring-dashpot may be connected to the wall of the mast by a ball-joint connection 213 in order to reduce friction on the motion of the linear spring-dashpot in a plane perpendicular to the direction along which it extends.
• the coupling device 211 may further comprise, in addition to the suspended linear spring-dashpot 212, a second linear spring-dashpot 214 that also extends transversally to the motion of the mass.
• the mass 210 may be positioned between the two linear springdashpots 212,214, with the first suspended spring-dashpot 212 extending from a wall of the mast to an upper end of the mass, and a second spring-dashpot 214 extending from a lower end of the mass to a wall of the mast, with the anchoring points of the spring-dashpots forming an axis parallel to the axis X-X of the mast.
• the second linear spring-dashpot 214 may also be connected to the wall of the mast by a balljoint connection 215.
• the vibration control system 20 is further configured to apply linear stiffness on a motion of the mass 210 perpendicular to the axis X-X of the mast and perform linear damping of said motion. This may for instance be achieved, when the mass is positioned inside the mast 10, by the vibration control system 20 comprising an additional linear spring-dashpot 22 that extends perpendicular to the axis X-X of the mast, and which is movable in rotation about an axis parallel to this axis, as in the examples described in more details below represented in figures 3, 4, 6 and 7.
• a spiral spring 22’ which axis is parallel to X-X and coupled to a linear viscoelastic damper may provide the linear stiffness and damping in any direction perpendicular to the axis X-X.
• linear stiffness and damping may be achieved by the vibration control system 20 comprising an additional linear spring-dashpot 22 that extends parallel to the axis Y-Y of the nacelle.
• the additional linear spring-dashpot 22 connected on one end to the mass 210 and on the other end to the wall 111 of the nacelle may also rotate relative to the axis of the mast according to the direction of the wind.
• k 3 N is the cubic stiffness coefficient and c N v N is the nonlinear viscous damping coefficient of the coupling device 211 when biased in a direction perpendicular to the axis X-X of the mast
• kiN is the linear stiffness
• CN is the linear damping coefficient of the additional device 22, 22’ for instance of the additional linear spring-dashpot.
• results obtained by numerical simulation of the vibrational behavior of a floating wind turbine comprising a non-linear energy sink are given in decibel, calculated as 20Log(
• the vibration control system 20 may further be configured to maintain the motion of the mass 210 within a plane perpendicular to the axis X-X of the mast. Therefore, it is ensured that the motion of the mass is perpendicular to the axis of the mast and hence that the non-linear stiffness and non-linear viscous damping of the coupling device 211 are applied to the mass.
• the mass may be enabled to have a motion in any direction within the plane perpendicular to the axis X-X, in order to allow the direction of motion to change according to the direction of the loads applied to the mast. Indeed, according to the direction of the wind, of the waves and of the current, the axis about which the mast oscillates may vary. Allowing the mass to move in any direction perpendicular to the motion of the mast thus enables damping vibrations of the wind turbine in all situations.
• the vibration control system 20 may for instance comprise a slide link 23 connecting the mass to a wall of the turbine, the slide link extending perpendicular to the axis X- X of the mast, and being movable in rotation about the axis of the mast.
• the slide link then ensures that the motion of the mass is perpendicular to the axis X-X of the mast, and the direction of the motion can change according to the direction of the loads applied to the mast and hence according to the motion of the mast.
• the slide link 23 may also enable a rotation about the axis along which it extends.
• the slide link 23 when the mass is positioned within the mast 10, the slide link 23 may be connected at one end to the mass 210 and at the other end to an intermediate structure 24 that is pivotably rotatable relative to an axis parallel to the axis X-X of the mast.
• the slide link 23 when the mass 210 is positioned within the nacelle 11 , the slide link 23 may extend along the axis Y-Y of the nacelle, said direction being perpendicular to the axis X-X of the mast, and may comprise one end connected to the mass 210 and the other end connected to a wall 111 of the nacelle.
• maintaining the mass 210 within a plane perpendicular to the axis X-X of the mast may be performed by suitably tuning the stiffness of the nonlinear energy sink and/or the linear stiffness applied to the mass in the direction of its motion (i.e. perpendicular to the axis of the mast).
• the floating wind turbine comprises a slide link 23 or a linear spring-dashpot 22 providing linear stiffness and damping of the motion of the mass perpendicular to the axis X-X of the mast
• a slide link 23 or a linear spring-dashpot 22 providing linear stiffness and damping of the motion of the mass perpendicular to the axis X-X of the mast
• the nonlinear energy sink may be bistable, i.e exhibit two stable positions of stability.
• bistable nonlinear energy sink has been shown in the article by V. lurasov and P.-O. Mattei, “Bistable nonlinear damper based on a buckled beam configuration”, Nonlinear Dynamics, 2019. (hal-02369738). This may be achieved for instance by using a mass which is asymmetric relative to the coupling device, for instance which center of gravity is offset relative to the axis formed by the connection points between the mass and the two dashpots to which it is connected.
• FIGS. 2 to 4, 6 and 7 are shown a plurality of examples of nonlinear energy sinks 21 in which the mass 210 is positioned within the mast 10 of the floating wind turbine 1.
• the mass 210 is positioned within the mast 10 of the turbine and the coupling device 211 comprises two linear spring-dashpots 212, 214 that extend generally along a direction parallel to the axis X-X of the mast 10.
• the mass 210 is interposed between the two spring-dashpots 212, 214, with each spring-dashpot connecting a respective end of the mass to a wall 101 of the mast, via a respective ball-joint connection 213,215.
• the two springdashpots may be connected to walls of the mast at anchoring points forming an axis parallel to the axis X-X of the mast.
• the vibration control device may further comprise an additional damper, for instance in the form of a spiral spring coupled to linear viscoelastic damper 22’.
• the additional damper may comprise an additional linear spring-dashpot 22 extending perpendicularly to the axis X-X of the mast.
• the vibration control device also comprises a slide link 23 extending parallel to the additional linear spring-dashpot 22, the latter and the slide link and being mounted on an intermediate structure 24 movable in rotation relative to an axis that is parallel to the direction of the mast.
• the mass is asymmetric relative to the axis formed by the ends of the two spring-dashpots 212, 214 to which it is connected, in order to provide a bistable system.
• the coupling device 211 of the nonlinear energy sink 21 comprises a single linear spring-dashpot 212 connected at one end to the mass 210 and at the other end to the wall of the mast by a ball-joint connection 213.
• the linear spring-dashpot 323 may be connected to the mass by its lower end and suspended by its upper end.
• the vibration control device 20 further comprises an additional linear spring-dashpot 22 and a slide link 23 extending perpendicularly to the axis X-X of the mast and movable in rotation relative to an axis parallel to said axis X-X.
• the slide link 23 and additional linear spring-dashpot 22 are connected by one end to the mass and by the other end to an intermediate structure 24 movable in rotation about an axis parallel to the axis X-X of the mast.
• the coupling device 211 of the NES comprises a linear dashpot 212 extending transversely to the motion of the mass within a horizontal plane, and an additional linear dashpot 22 and slide link 23 also extending within a horizontal plane.
• the mass 210 thus has a motion that is along the axis of the slide link 23.
• these elements are mounted on an intermediate structure 24 which is mounted in translation relative to the mast according to an axis which is perpendicular to the axis X-X of the mast and perpendicular to the slide link 23.
• the translation according to the axis X-X may be subject to both linear and non-linear stiffness 240, 240’, and to both linear and nonlinear damping 241 , 24T.
• This embodiment allows a horizontal motion of the mass without the use of rotation devices.
• the coupling device 211 comprises a linear spring-dashpot 212 extending transversely to the motion of the mass, and connected to a wall of the nacelle by a ball-joint connection. Said motion of the mass is maintained in a direction perpendicular to the axis X-X of the mast using a slide link 23.
• the slide link can for instance extend parallel to the axis Y-Y of the nacelle.
• the vibration control device 20 further comprises a linear spring-dashpot 22 extending parallel to the axis Y-Y of the nacelle to provide linear stiffness and damping of the motion of the mass according to said direction.
• the direction of the motion 10 of the mass can also rotate relative to the mast according to the direction of the wind on the floating wind turbine.
• the linear springdashpots that are biased transversely by the motion of the mass may further be guided by an additional slide link 25, in order to force the motion of the linear springdashpots along their respective direction and prevent them from having a pendular motion.
• the guiding function is represented on the figures by a device which is distinct from the spring, this function may also be performed by the spring.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Wind Motors (AREA)

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• 2022
  • 2022-12-21 EP EP22306970.9A patent/EP4390115A1/de not_active Withdrawn
• 2023
  • 2023-12-12 EP EP23821665.9A patent/EP4638943A1/de active Pending
  • 2023-12-12 WO PCT/EP2023/085393 patent/WO2024132713A1/en not_active Ceased

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