Floating wind turbine foundation

Abstract

The present invention relates to an offshore floating wind turbine foundation comprising at least two outer members arranged around a tower comprising a rotor-nacelle assembly with blades wherein a plurality of pairs of beams connect a central buoy and the at least two outer members, a pair of beams tapers from the tower toward each of the at least two outer members.

Description

[0001] The present invention is in the field of wind power generation and relates to an offshore floating foundation, and more specifically to a floating wind turbine foundation.

[0002] In the study of the design of floating offshore wind turbine foundations used in various marine projects, structural efficiency in terms of weight and shape, as well as motion characteristics, are clearly success criteria for most successful units.

[0003] For floating structures of offshore wind turbines, triangular shapes are generally preferred because they have higher strength, stiffness and hydrostatic stability relative to size, and therefore have an advantage in terms of required materials, which is critical for large wind turbines.

[0004] In triangular floating wind turbine platforms, each corner typically includes one or more vertical buoyancy columns, and the wind turbine tower can typically be positioned at the center of the triangle.

[0005] In the construction of some triangular floating platforms, positioning the wind turbine tower above one of the corners has become a preferred option because it makes it easier for a crane to reach the wind turbine tower when assembling and / or maintaining the wind turbine tower. However, it has proven that the corner position is not the best choice because the added weight of the wind turbine tower positioned on one corner needs to be compensated by additional buoyancy and a corresponding or equivalent buoyancy and weight added on the other two corners to achieve hydrodynamic symmetry, which is critical to avoid unnecessary coupled motion of the platform due to wave action on the platform. Therefore, installing a 2000-ton turbine on one corner requires adding 2000 tons of ballast on each of the other two corners. Such a large weight on one corner results in an undesirable draft, which is typically more than 15 meters. In near-shore operations, a draft of no more than 15 meters is preferred because it will significantly increase the number of ports available for such offshore wind installations.

[0006] In triangular configurations, the wind turbine tower is positioned on the central buoy between the three outer (“satellite”) buoys. The three outer buoys are typically connected to the central buoy by horizontal upper and lower cantilever beams and diagonal beams in the vertical plane. The upper horizontal cantilever beam is typically referred to as the deck beam, and the lower horizontal cantilever beam is typically referred to as the pontoon. The design driving loads on these beams are typically wave loads from a direction substantially perpendicular to the line connecting the center of the same outer buoy to the central buoy. These wave loads can generate large bending moments on the upper and lower cantilever beams, resulting in oversized structures, increased steel weight, and increased construction costs.

[0007] For floating offshore wind turbine platforms anchored with vertical tension mooring members (tension leg platforms), the stability during towing and installation and the process of lowering the platform to the final depth by the tensioned vertical mooring members is very complex and costly due to lack of proper installation methods and installation aids.

[0008] It is an object of the present application to reduce one or more of the drawbacks of the prior art as far as possible or to provide a useful alternative.

[0009] It is a further object of the present application to provide a floating wind turbine foundation which is less affected by wave, wind and current loads.

[0010] The present application relates to a floating offshore wind turbine foundation, wherein the floating offshore wind turbine foundation comprises at least two outer members arranged around a central buoy and a tower comprising a rotor-nacelle assembly with blades, wherein a plurality of pairs of beams are arranged between the central buoy and the at least two outer members to connect the central buoy and the outer members and each pair of beams is arranged tapering from the central buoy towards each of the at least two outer members.

[0011] The plurality of pairs of beams will form one or more A-frames in the floating offshore wind turbine foundation, wherein the floating offshore wind turbine foundation can be provided with one A-frame, such as an upper A-frame or a lower A-frame, or the floating offshore wind turbine foundation can be provided with two A-frames, i.e. an upper A-frame and a lower A-frame.

[0012] According to the present application, an outer member of the floating offshore wind turbine foundation is to be understood as a member to which the pairs of beams are to be connected.

[0013] Such outer members can for example be buoys, nodes, combined buoys and nodes, etc.

[0014] Further, according to an aspect, the outer members can house ballast. The ballast can be water or any other form of liquid or solid ballast.

[0015] Similarly, the central buoy and / or the beams can house ballast, wherein the ballast can be water or any other form of liquid or solid ballast.

[0016] As used in the present application, a "node" is to be understood as a connection point or branching point where the end of a beam in a pair of beams terminates / starts. Further, it is to be understood that such nodes can be single points or can have an area range.

[0017] At the outer members, due to the structurally efficient pairs of beams forming one or more A-frames in the offshore floating wind turbine foundation, mooring lines arranged for transferring heavy loads can be connected to the outer members to ensure that the offshore floating wind turbine foundation remains in position during operation.

[0018] In one embodiment, the offshore floating wind turbine foundation can comprise at least two outer floats arranged around a central float and a tower comprising a rotor-nacelle assembly with blades, wherein a plurality of beams connects the central float and the at least two outer floats, the plurality of beams forming a plurality of pairs of beams, the pairs of beams tapering from the tower towards each of the at least two outer floats.

[0019] The tower with the rotor-nacelle assembly and blades can be connected to the central float in an appropriate manner, or the tower can be an integral part of the central float.

[0020] According to one aspect, the diameter of the tower can be smaller than the diameter of the central float, whereby the tower can be assembled with the central float by extending a distance below the central float, thereby forming a pipe-in-pipe connection.

[0021] According to one aspect, the beams in the pairs of beams extending from the central float to each outer member can be arranged to lie in a given plane, which given plane may, for example, be a substantially horizontal plane. However, it should be understood that the beams in each pair of beams (individually or both) can be arranged to form an angle with the given plane.

[0022] Furthermore, it is also conceivable that the given plane can be arranged to lie between a substantially horizontal plane and a substantially vertical plane.

[0023] According to one embodiment of the present invention, one or more support structures can be connected to the central float of the offshore floating wind turbine foundation.

[0024] According to one aspect, the support structure can comprise a central portion and at least three arms extending outwardly from the central portion, wherein the arms can be arranged at equal intervals around the circumference of the central portion.

[0025] In one embodiment, the arms can have a tapering form from a proximal end to a distal end.

[0026] Such a support structure can be a stand-alone unit, which is attached or connected to the central float in an appropriate manner, such as by welding or bolting, or the support structure can be an integral part of the central float.

[0027] Furthermore, if more than one support structure is used, the support structures should be arranged in such a way that they are connected to the central buoy at a distance from each other. For example, if two support structures are to be connected to the central buoy, one support structure can be connected to the central buoy in such a way that its height substantially corresponds to the height of the upper end of the outer buoy, while the other support structure can be connected to the central buoy in such a way that its height is close to the lower part of the central buoy.

[0028] According to one aspect, the plurality of pairs of beams can be arranged in such a way that the distal end of the pair of beams can be connected to the outer buoy near the upper part of each of the at least two outer buoys, near the lower part of each of the at least two outer buoys, or near the upper and lower part of each of the at least two outer buoys.

[0029] According to the present invention, each of the outer buoys can have a circular shape, a square shape, a rectangular shape, a boat shape, a parabolic shape, an elliptical shape, or a polygonal shape. Furthermore, in one embodiment, the outer buoy can have the same cross-section over its entire height or length, but it can also be envisaged that the outer buoy can be designed with a varying cross-section over its length or height, for example, in such an embodiment, the outer buoy can have a larger cross-section at the lower end and a smaller cross-section at the upper end.

[0030] Furthermore, the variation in cross-section can be gradual or continuous over the length or height of the outer buoy, or the variation in cross-section can be sudden or abrupt over the length or height of the outer buoy.

[0031] According to one aspect of the present invention, the beams in each pair of beams can be arranged in such a way that the imaginary intersection point of the center lines of the distal ends of the beams can lie within the circumference of the outer buoy.

[0032] According to the present invention, the imaginary intersection point between the beams in the pair of beams is to be understood as the point at which the beams in the pair of beams, when they are imagined to be extended, intersect or meet each other.

[0033] In one embodiment according to the present invention, the beams in each pair of beams can be arranged in such a way that the imaginary intersection point of the center lines of the distal ends of the beams can lie within a circle, wherein the radius of the circle can be less than 1 / 3 of the circumferential radius of the outer buoy, and the circle can be arranged concentrically with the outer buoy.

[0034] However, it can also be envisaged that the circle can be arranged eccentrically with respect to the outer buoy.

[0035] According to one aspect of the present invention, each pair of beams can be arranged in such a way that the proximal end of the pair of beams can be connected to a support structure of the tower.

[0036] In one aspect, the at least two outer buoys and the central buoy can be arranged in an equilateral triangle.

[0037] According to one aspect, the beams in a pair of beams can be arranged in structural communication with one or more of the adjacent pair of beams to transfer loads and / or forces between the pair of beams and / or the central buoy.

[0038] According to one aspect, the offshore floating wind turbine foundation can further comprise a damper device, wherein the damper device can be connected to the lower end of each outer buoy and / or central buoy.

[0039] In one aspect of the invention, at least one strut can be arranged to extend from each outer buoy to the upper end of the central buoy.

[0040] In one aspect of the invention, at least one strut can be arranged to extend from the upper end of each outer buoy to the lower support structure of the tower.

[0041] In one aspect of the invention, at least one strut can be arranged to extend from the lower end of each outer buoy to the upper support structure of the tower.

[0042] In one aspect of the invention, at least one strut can be arranged to extend from the lower outer member to the upper support structure of the tower.

[0043] In yet another aspect of the invention, one strut can be arranged to extend from the upper end of each outer buoy to the lower support structure of the tower, and another strut can be arranged to extend from the lower end of each outer buoy to the upper support structure of the tower.

[0044] In one embodiment, the one or more struts can be connected to the support structure of the tower between the beams in the pair of beams, or directly to the tower, when viewed from above.

[0045] The one or more struts can be rigid members in the form of beams, tubes, etc.

[0046] According to one aspect, the one or more struts can be arranged as pre-tensioned structural members, thereby having bending flexibility like wire or rods, etc.

[0047] In one embodiment, the offshore floating wind turbine foundation can comprise a trim / ballast system, wherein ballast water can be communicated between each outer buoy and the opposing two beams or the opposing two outer buoys, wherein the trim / ballast system can comprise a pressure air system.

[0048] In an embodiment according to the present application, the offshore floating wind turbine foundation can be designed such that a plurality of pairs of beams can be arranged to extend from the upper support structure of the central buoy to the vicinity of the lower part of each outer buoy, the pairs of beams forming an A-frame in the offshore floating wind turbine foundation.

[0049] In another embodiment according to the present application, the offshore floating wind turbine foundation can be designed such that a plurality of pairs of beams can be arranged to extend from the lower support structure of the central buoy to the vicinity of the upper part of each outer buoy, the pairs of beams forming an A-frame in the offshore floating wind turbine foundation.

[0050] In yet another embodiment according to the present application, the offshore floating wind turbine foundation can be designed such that a plurality of pairs of beams can be arranged to extend from the upper support structure of the central buoy to the vicinity of the upper part of each outer buoy, while a plurality of pairs of beams can be arranged to extend from the lower support structure of the central buoy to the vicinity of the lower part of each outer buoy, the plurality of pairs of beams forming an upper A-frame and a lower A-frame in the offshore floating wind turbine foundation.

[0051] According to an aspect of the present application, the beams in a pair of beams can be arranged in such a way that the angle a in the pair of beams lies within the interval of 5 degrees to 55 degrees.

[0052] In an aspect of the present application, the proximal end of the beams in each pair of beams can be connected to the circumference of the central buoy.

[0053] In another aspect of the present application, the proximal end of the beams in each pair of beams can be connected to a support structure, which is further connected to the central buoy.

[0054] According to yet another aspect of the present application, the distance between the proximal ends of the beams in each pair of beams can be less than the diameter D of the central buoy.

[0055] In another aspect of the present application, the distance between the proximal ends of the beams in each pair of beams can be equal to or greater than the diameter D of the central buoy.

[0056] In another aspect of the application, a plurality of tensioned vertical anchoring members can be connected between the offshore floating wind turbine foundation (i.e. each outer node or each outer buoy) and the corresponding anchor located on the underlying seabed. In this aspect of the application, a very efficient Tension Leg Platform (TLP) is disclosed, wherein pairs of beams provide the necessary buoyancy to ensure that the tension legs have sufficient tension and to guarantee stability during the towing process. Since during the towing process, each pair of beams can pierce the water surface, thereby contributing to the increase in hydrostatic stability due to the increase in waterplane area. Furthermore, due to the A-frame configuration, the pairs of beams form very strong nodes for the connection of mooring lines, in particular for the transfer of horizontal forces resulting from wave loads.

[0057] In one aspect of the application, a vertical jacking tower can be connected to one or more outer members, and the vertical jacking tower can be arranged to extend above each outer node or buoy, the jacking tower further being arranged for the installation of jacking members to secure the vertical anchoring members to the appropriate pretensioning level. The jacking tower can be arranged to resist the compressive forces resulting in response to the vertical downward force applied to the jacking tower from the jacks during the pretensioning jacking operation of the vertical mooring lines. The pretension of the vertical anchoring members can be arranged to ensure that the outer buoys and / or pairs of beams are fully submerged after the completion of the jacking operation. However, it should be understood that the outer buoys and / or pairs of beams can also be arranged to be partially submerged in water.

[0058] In one aspect of the application, the top of the jacking tower remains above the waterline after the completion of the jacking operation, thereby enabling the jacking members to work in dry conditions. The jacking members can be any type of jack, such as hydraulic jacks, electric jacks or any other type of jack. The jacking members can be located in the upper part of the jacking tower. After the completion of the jacking operation, the vertical mooring members can be mechanically fixed, such that the jacks are removed. In one aspect of the application, the vertical jacking tower is removed from the outer buoy after the completion of the jacking operation.

[0059] In yet another aspect of the invention, the mooring members are connected by one end thereof to one of the outer buoys and by the opposite end to an anchor located on the seabed. In one aspect, the anchor can be a single anchor with a swivel allowing the floating wind turbine foundation to rotate around the seabed anchor as the wind direction, water flow and wave direction changes. In one aspect, the mooring members can comprise one or more separate mooring lines connected to the same outer node or buoy. Each mooring line can be arranged to be rigid such that they are able to resist at least some bending moment. In another aspect, at least a portion of the length of the mooring line can be arranged to be flexibly bending, substantially not transmitting bending moment. In another aspect, the mooring line can be arranged to resist torsional forces. In one aspect of the invention, the power cable can be connected to the mooring line.

[0060] In yet another aspect of the invention, the lower pair of beams can be arranged to be partially submerged in water and partially above water surface when floating during assembly of the floating platform and / or during offshore installation.

[0061] In yet another aspect of the invention, at least one pair of lower beams can be arranged to be partially submerged and partially above water surface when floating on the water surface in the final installed position.

[0062] In yet another aspect of the invention, at least one diagonal brace and pair of lower beams can be arranged to be connected together at the outer node member in the absence of the outer buoy.

[0063] In another embodiment of the invention, the floating wind turbine foundation is arranged to rotate around a single anchor on the seabed, furthermore, the outer buoy has a horizontal cross section with a length L pointing towards the single anchor during operation of the wind turbine and a width W perpendicular to the length L, wherein the length L is arranged to be larger than the width W, thereby reducing the wave and current forces acting on the floating platform in wave and wind driven water flow.

[0064] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0065] Figures 1A-1B A first embodiment of an offshore floating wind turbine foundation according to the invention is shown in perspective view and top view.

[0066] Figure 2 A second embodiment of an offshore floating wind turbine foundation according to the invention is shown in top view.

[0067] Figure 3 Another embodiment of an offshore floating wind turbine foundation according to the invention is shown in perspective view,

[0068] Figures 4A-4C Another embodiment of an offshore floating wind turbine foundation according to the present application is shown in perspective view and side view, wherein the floating wind turbine is anchored to the seabed by an anchoring system.

[0069] Figures 5A-5B Another embodiment of an offshore floating wind turbine foundation according to the present application is shown in perspective view and side view, wherein the floating wind turbine is anchored to the seabed by an anchoring system. Figures 4A-4C

[0070] Figure 6 Another embodiment of an offshore floating wind turbine foundation according to the present application is shown in perspective view and side view, wherein the floating wind turbine is anchored to the seabed by an anchoring system.

[0071] Figures 7A-7B Another embodiment of an offshore floating wind turbine foundation according to the present application is shown in perspective view and side view, wherein the floating wind turbine is anchored to the seabed by an anchoring system.

[0072] Figures 8A-8C Another embodiment of an offshore floating wind turbine foundation according to the present application is shown in perspective view and side view, wherein the floating wind turbine is anchored to the seabed by an anchoring system.

[0073] Figures 9A-9D A support and transport frame for supporting and / or transporting an offshore floating wind turbine foundation according to the present application is shown.

[0074] Figures 1A-1B A first embodiment of an offshore floating wind turbine foundation F according to the present application is shown, from which it can be seen that the offshore floating wind turbine foundation F comprises three outer members 2 and a centrally arranged buoyancy member (central buoyancy member) 1, wherein the outer members 2 are in the form of buoyancy members.

[0075] A tower T extends upwards from the central buoyancy member 1, wherein the tower T is an integral part of the central buoyancy member 1 or a separate unit which is connected to the central buoyancy member 1 in a suitable manner.

[0076] Each of the outer buoyancy members 2 has a circular shape and is designed to have the same cross-sectional area over its entire length or height.

[0077] However, it is to be understood that the outer buoyancy members 2 can also take other shapes, such as a square shape, a rectangular shape, an elliptical shape, a ship hull shape or a polygonal shape. Similarly, it is to be understood that the outer buoyancy members 2 can be designed to have a cross-sectional area which varies over its length or height, wherein the variation in cross-sectional area can be gradual or can be abrupt.

[0078] Additionally, the three outer buoyancy members 2 are arranged in an equidistant triangle. ​

[0079] Both the outer buoy 2 and the central buoy 1 have the same height or length, but it can be seen that the diameter d of the outer buoy 2 is larger than the diameter D of the central buoy 1.

[0080] The rotor-nacelle assembly 6 comprising the plurality of blades 7 is connected to the top of the tower T in a suitable manner.

[0081] Both support structures 3 are connected to the central buoy 1 in a suitable manner, wherein the lower support structure 3 is arranged to be connected to the lower end of the central buoy 1 and the upper support structure 3 is arranged to be connected to the central buoy 1 at a distance from the lower support structure 3.

[0082] Each support structure 3 can be a separate unit that is attached or connected to the central buoy 1 by means of e.g. welding or bolting, but the support structure 3 can also be an integral part of the central buoy 1.

[0083] In embodiments where the support structure 3 is a separate unit that is connected to the central buoy 1, the support structure 3 comprises a central part 3A, wherein three "arms" 3B extend outwardly from the central part 3A.

[0084] In embodiments where the support structure 3 is an integral part of the central buoy 1, the central buoy 1 will constitute or form the central part 3A of the support structure, so that the three arms 3B will extend outwardly from the central buoy 1.

[0085] The three "arms" 3B are arranged at equal intervals around the circumference of the central part 3A or the central buoy 1.

[0086] Furthermore, each of the three "arms" 3B will taper from a proximal end of the "arm" 3B, i.e. the end connected to the central part 3A of the support structure 3 or the central buoy 1, to a distal end of the "arm" 3B, i.e. the end to be connected to the beam 4C.

[0087] The central buoy 1 and the three outer buoys 2 are interconnected by a plurality of beams 4A, 4B, wherein the plurality of beams 4A, 4B are arranged to form a plurality of pairs of beams 4C.

[0088] The pairs of beams 4C are then arranged to extend between the tower 1 and the respective outer buoy 2, wherein the beams 4A, 4B of the pairs of beams 4C are arranged to taper from the central buoy 1 to the outer buoy 2, the beams 4A, 4B of the pairs of beams being connected to the outer buoy 2. This will result in the beams 4A, 4B of the pairs of beams being arranged in such a way that the distance between the proximal ends of the beams 4A, 4B connected to the central buoy 1 is larger than the distance between the distal ends of the beams 4A, 4B connected to the outer buoy 2.

[0089] Furthermore, the beams 4A, 4B in the pairs of beams 4C are arranged such that the centre lines of the beams 4A, 4B in the pairs of beams do not cross each other between the central buoy 1 and the respective outer buoy 2, but the distal ends of the beams 4A, 4B in the pairs of beams 4C are arranged to be close to each other or abutting each other when connected to the respective outer buoy 2.

[0090] If the beams 4A, 4C are considered to be extended, the imaginary intersection point of the centre lines of the beams 4A, 4B in the pairs of beams 4C is located within the circumference of the outer buoy 2.

[0091] In embodiments, the imaginary intersection point can be arranged within a circle 30 having a radius less than 1 / 3 of the circumferential radius of the outer buoy 2, wherein the circle 30 is arranged concentrically with the outer buoy 2.

[0092] It is also shown that a plurality of struts 5 are arranged between the pairs of upper beams, pairs of lower beams 4C, wherein one strut 5 is arranged to extend from an upper end of each outer buoy 2 to the lower support structure 3 of the central buoy 1, and another strut 5 is arranged to extend from a lower end of each outer buoy 2 to the upper support structure 3 of the central buoy 1.

[0093] Seen from above, see also Figure 1B , the struts 5 are arranged to extend between the beams 4A, 4B forming the pairs of beams 4C.

[0094] The struts 5 are beams, tubes or similar forms of rigid members.

[0095] Furthermore, the struts 5 are arranged as flexible bendable pre-tensioned structural members.

[0096] In this embodiment of the offshore floating wind turbine foundation F, the plurality of pairs of beams 4C will form an upper A-frame and a lower A-frame.

[0097] Figure 2 Another embodiment of an offshore floating wind turbine foundation F according to the present application is shown seen from above, wherein the offshore floating wind turbine foundation F comprises three outer members 2 arranged around a central buoy 1, said outer members 2 being in the form of buoys, the three outer buoys 2 being arranged in an equilateral triangle at equal intervals.

[0098] The central buoy 1 is not visible from this view, but it is arranged below the support structure 3 connected to the central buoy 1.

[0099] Furthermore, the offshore floating wind turbine foundation F comprises a tower T, but the tower T is not shown in the figures for simplicity. However, it should be understood that the tower T is arranged to extend upwards from the central buoy 1, wherein the tower T is either an integral part of the central buoy 1 or a separate unit connected to the central buoy 1 in a suitable manner.

[0100] The rotor-nacelle assembly 6 is connected to the top of the tower T.

[0101] The outer buoy 2 and the central buoy 1 have a circular shape and are designed to have the same cross section over their entire length or height.

[0102] The outer buoy 2 and the central buoy 1 both have the same height or length, but it can be seen that the diameter d of the outer buoy 2 is larger than the diameter D of the central buoy 1.

[0103] Furthermore, two support structures 3 Figure 2 Only the upper support structure is shown) are connected to the central buoy 1, wherein the lower support structure 3 is connected to the lower end of the central buoy 1, while the upper support structure 3 is arranged at a distance above the central buoy 1, spaced apart from the lower support structure 3.

[0104] Each support structure 3 can be a separate unit that is attached or connected to the central buoy 1 by means of, for example, welding or bolting, but the support structure 3 can also be an integral part of the tower central buoy 1.

[0105] In embodiments in which the support structure 3 is a separate unit that is connected to the central buoy 1, the support structure 3 comprises a central part 3A, from which three “arms” 3B extend outwardly.

[0106] In embodiments in which the support structure 3 is an integral part of the central buoy 1, the central buoy 1 will comprise three “arms” 3B that extend outwardly from the central buoy 1.

[0107] The three arms 3B are arranged at equal intervals around the circumference of the central part 3A or the central buoy 1.

[0108] Furthermore, each of the three arms 3B will taper from the proximal end of the “arm” 3B, i.e. the end connected to the central part 3A of the support structure 3 or the central buoy 1, to the distal end of the “arm” 3B, i.e. the end to be connected to the pair of beams 4C.

[0109] In this embodiment, the central buoy 1 is connected to each of the three outer buoys 2 by two support structures 3 and a plurality of beams 4A, 4B, wherein the plurality of beams 4A, 4B are arranged to form a plurality of pairs of beams 4C.

[0110] The pairs of beams 4C are then arranged to extend between the support structures 3 connected to the central buoy 1 and the respective outer buoy 2, wherein the beams 4A, 4B in the pairs of beams 4C are arranged to taper from the support structure 3 to the outer buoy 2 to which the beams 4A, 4B are connected. This will result in the beams 4A, 4B being arranged such that the distance between the proximal ends of the beams 4A, 4B connected to the support structure 3 is larger than the distance between the distal ends of the beams 4A, 4B connected to the outer buoy 2.

[0111] In this embodiment, the arms 3B extending out from the central part 3A of the support structure 3 have a length such that the beams 4A, 4B in the pairs of beams 4C will form a "straight line" between two adjacent outer floats 2.

[0112] Furthermore, the arrangement of the beams 4A, 4B in the pairs of beams 4C is such that the centre lines of the beams 4A, 4B do not cross each other between the support structure 3 and the respective outer float 2, but the distal ends of the beams 4A, 4B in the pairs of beams 4C are arranged close to or abutting each other.

[0113] If the beams 4A, 4C are considered to be extended, the imaginary intersection point of the centre lines of the beams 4A, 4B in the pairs of beams 4C is located within the circumference of the outer float 2.

[0114] In embodiments, the imaginary intersection point can be arranged within a circle 30 having a radius less than 1 / 3 of the circumferential radius of the outer float 2, wherein the circle 30 is arranged concentrically with the outer float 2.

[0115] Although Figure 2 Not shown in Fig. 1, but as will be understood, a plurality of struts 5 are arranged between the pairs of upper beams, the pairs of lower beams 4C, wherein one strut 5 extends from an upper end of each outer float 2 to a lower support structure 3 of the central float 1, and another strut 5 is arranged to extend from a lower end of each outer float 2 to an upper support structure 3 of the central float 1.

[0116] The struts 5 are beams, tubes or similar forms of rigid members.

[0117] Furthermore, the struts 5 are arranged as flexible bendable pre-tensioned structural members.

[0118] In this embodiment of the offshore floating wind turbine foundation F, the plurality of pairs of beams 4C will form an upper A-frame and a lower A-frame, although the lower A-frame is not shown in the figure.

[0119] Figure 3 A further embodiment of an offshore floating wind turbine foundation F according to the present application is shown, wherein the offshore floating wind turbine foundation F comprises three outer members 2 arranged around a central float 1, said outer members 2 being in the form of floats, the three outer floats 2 being arranged in an equilateral triangle at equal intervals.

[0120] Furthermore, the offshore floating wind turbine foundation F comprises a tower T, but for simplicity the tower T is not shown in the figure. However, it will be understood that the tower T is arranged to extend upwards from the central float 1, wherein the tower T is either an integral part of the central float 1 or a separate unit connected to the central float 1 in a suitable manner.

[0121] The rotor-nacelle assembly 6 is connected to the top of the tower T, see also Fig. 1, where the tower T and the rotor-nacelle assembly 6 are shown.

[0122] The outer buoy 2 and the central buoy 1 have a circular shape and are designed to have the same cross section over their entire length or height.

[0123] The outer buoy 2 and the central buoy 1 have the same height or length, but it can be seen that the diameter d of the outer buoy 2 is larger than the diameter D of the central buoy 1.

[0124] Furthermore, two support structures 3, Figure 2 only the upper support structure is shown, are connected to the central buoy 1, wherein the lower support structure 3 is connected to the lower end of the central buoy 1 and the upper support structure 3 is arranged at a distance above the central buoy 1, spaced apart from the lower support structure 3.

[0125] Each support structure 3 can be a stand-alone unit, which is attached or connected to the central buoy 1 by means of e.g. welding or bolting, but the support structure 3 can also be an integral part of the tower central buoy 1.

[0126] In embodiments where the support structure 3 is a stand-alone unit connected to the central buoy 1, the support structure 3 comprises a central part 3A, wherein three “arms” 3B extend outwardly from the central part 3A.

[0127] In embodiments where the support structure 3 is an integral part of the central buoy 1, the central buoy 1 will comprise three “arms” 3B extending outwardly from the central buoy 1.

[0128] The three “arms” 3B are arranged at equal intervals around the circumference of the central part 3A or the central buoy 1.

[0129] Furthermore, each of the three “arms” 3B will taper from a proximal end of the “arm” 3B, i.e. the end connected to the central part 3A of the support structure 3 or the central buoy 1, to a distal end of the “arm” 3B, i.e. the end to be connected to the end of the pair of beams 4C.

[0130] In this embodiment, the central buoy 1 is connected to each of the three outer buoys 2 by the support structure 3 and a plurality of beams 4A, 4B, wherein the plurality of beams 4A, 4B are arranged to form a plurality of pairs of beams 4C.

[0131] Then, pairs of beams 4C are arranged extending between the support structure 3 connected to the central buoy 1 and the respective outer buoy 2, where the beams 4A, 4B in the pairs of beams 4C are arranged tapering from the support structure 3 towards the outer buoy 2 to which the beams 4A, 4B are connected. This will result in the beams 4A, 4B being arranged with a distance between the proximal ends of the beams 4A, 4B connected to the support structure 3 being larger than a distance between the distal ends of the beams 4A, 4B connected to the outer buoy 2.

[0132] In the present embodiment, the arms 3B extending outwards from the central portion 3A of the support structure 3 have a length such that the beams 4A, 4B in the pairs of beams 4C will form an "angled line" between two adjacent outer buoys 2.

[0133] Furthermore, the beams 4A, 4B in the pairs of beams 4C are arranged such that the centre lines of the beams 4A, 4B do not cross each other between the support structure 3 and the respective outer buoy 2, but the distal ends of the beams 4A, 4B in the pairs of beams 4C are arranged close to or abutting each other.

[0134] If the beams 4A, 4C are considered to be extended, the beams 4A, 4B in the pairs of beams 4C will have an imaginary intersection point located within the circumference of the outer buoy 2.

[0135] In embodiments, the imaginary intersection point can be arranged within a circle 30 having a radius less than 1 / 3 of the circumferential radius of the outer buoy 2, where the circle 30 is arranged concentrically with the outer buoy 2.

[0136] Furthermore, a plurality of struts 5 are provided between the pairs of upper beams, pairs of lower beams 4C, where one strut 5 is provided extending from an upper end of each outer buoy 2 to a lower support structure 3 of the central buoy 1, and another strut 5 is provided extending from a lower end of each outer buoy 2 to an upper support structure 3 of the central buoy 1.

[0137] The struts 5 are beams, tubes or similar forms of rigid members.

[0138] Furthermore, the struts 5 are arranged as flexible bendable pre-tensioned structural members.

[0139] The beams 4A, 4B in the pairs of beams 4C can be arranged in such a way that the angle a in the pairs of beams 4C is within an interval of between 5 degrees and 55 degrees.

[0140] Figures 4A-4C A further embodiment of an offshore floating wind turbine foundation according to the present application is shown, where the offshore wind turbine foundation F comprises three outer members 2 arranged around a central buoy 1, which outer members 2 are in the form of buoys, and the three outer buoys 2 are arranged in an equilateral triangle at equal intervals.

[0141] As can be seen, the tower T is arranged to extend upwards from the central buoy 1, wherein the tower T is either an integral part of the central buoy 1 or a separate unit connected to the central buoy 1 in a suitable manner.

[0142] The rotor-nacelle assembly 6 with the plurality of blades 7 is connected to the top of the tower.

[0143] In this embodiment, the three outer buoys 2 and the central buoy 1 all have a circular shape, but the diameter d of the outer buoys 2 is larger than the diameter D of the central buoy 1. Furthermore, the height or length of the central buoy 1 is larger than the height or length of the three outer buoys 2.

[0144] The outer buoys 2 can contain ballast. The ballast can be water or any other form of liquid or solid ballast.

[0145] The central buoy 1 can contain ballast. The ballast can be water or any other form of liquid or solid ballast.

[0146] The beams (4A, 4B) can contain ballast. The ballast can be water or any other form of liquid or solid ballast.

[0147] The support structure 3 is connected to the lower end of the central buoy 1, e.g. by means of welding or bolting. However, it should be understood that the support structure 3 can also be an integral part of the central buoy 1.

[0148] The support structure 3 comprises a central portion 3A and three arms 3B extending outwardly from the central portion 3A of the support structure 3, wherein the three arms 3B are arranged at equal intervals around the central portion 3A of the support structure 3 or the periphery of the central buoy 1.

[0149] Furthermore, each of the three “arms” 3B will taper from the proximal end of the arm 3B, i.e. the end connected to the central portion 3A of the support structure 3 or the central buoy 1, to the distal end of the arm 3B, i.e. the end to be connected to the beam 4C.

[0150] In this embodiment, the central buoy 1 is connected to each of the three outer buoys 2 by means of the support structure 3 and a plurality of beams 4B, respectively, wherein the plurality of beams 4B are arranged to form a plurality of pairs of beams 4C.

[0151] The pairs of beams 4C are then arranged to extend between the support structure 3 connected to the central buoy 1 and the respective outer buoy 2, wherein the beams 4B in the pairs of beams 4C are arranged to taper from the support structure 3 to the outer buoy 2 to which the beam 4B is connected. This will result in the beams 4B being arranged such that the distance between the proximal ends of the beams 4B connected to the support structure 3 is larger than the distance between the distal ends of the beams 4B connected to the outer buoys 2.

[0152] In the present embodiment, the arms 3B extending outwardly from the central portion 3A of the support structure 3 have a length such that the beams 4B in the pairs of beams 4C will form an "angled line" between two adjacent outer floats 2.

[0153] Furthermore, the beams 4B in the pairs of beams 4C are arranged such that the centerlines of the beams 4B do not cross each other between the support structure 3 and the respective outer float 2, but the distal ends of the beams 4B in the pairs of beams 4C are arranged close to or abutting each other.

[0154] If the beams 4C are considered to be extended, the centerlines of the beams 4B in the pairs of beams 4C will have an imaginary intersection point located within the circumference of the outer float 2.

[0155] In embodiments, the imaginary intersection point can be arranged within a circle having a radius less than 1 / 3 of the circumferential radius of the outer float 2, wherein the circle is arranged concentrically with the outer float 2.

[0156] Furthermore, a plurality of struts 5 are arranged between the pairs of beams 4C, wherein one strut 5 is arranged to extend from each outer member 2 to the upper end of the central float 1.

[0157] The struts 5 are beams, tubes or similar forms of rigid members.

[0158] Furthermore, the struts 5 are arranged as flexible bendable pre-tensioned structural members.

[0159] The offshore floating wind turbine foundation F further comprises an anchoring system, wherein the anchoring system comprises a (vertical) jacking tower 15 arranged on each outer float 2 and a plurality of vertical anchoring members 16. Each jacking tower 15 comprises a jacking member (not shown) for tensioning the plurality of vertical anchoring members 16 to a suitable pre-tensioning level.

[0160] The plurality of vertical anchoring members 16 are connected with corresponding anchor members 17 arranged below each outer float 2.

[0161] Furthermore, the jacking tower 15 is arranged to protrude a height from above the outer float 2 such that when the offshore floating wind turbine foundation F is submerged and anchored in its working position, a part of the jacking tower 15 will protrude above the water surface, see also Figure 8B .

[0162] The anchoring system in the present embodiment is a TLP system (Tension Leg Platform system).

[0163] Furthermore, Figure 4A The offshore floating wind turbine foundation F is shown in a state when being transported to the installation site, wherein the jacking towers 15 are in the process of tensioning the vertical anchoring members 16 to sink the floating wind turbine foundation F into its working position, asFigure 8B The floating wind turbine foundation F will then be transported to the installation site, at which point the beams 4 are located at the water surface and the beams 4 together with the outer floats 2 provide the necessary buoyancy and hydrostatic stability for the floating wind turbine foundation F.

[0164] Figures 4B-4C The floating wind turbine foundation F is shown in its working position, with the outer floats 2 fully submerged and only a portion of the jacking towers 15 extending above the water surface, the floating wind turbine foundation F being anchored to the seabed by means of a plurality of vertical anchoring members 16.

[0165] A method for anchoring a floating offshore wind turbine foundation F can comprise the following steps:

[0166] - transporting the floating offshore wind turbine foundation F to the installation site,

[0167] - connecting a plurality of anchoring members 16 to a respective anchoring piece 17 arranged below each outer float 2,

[0168] - connecting a float member (not shown) provided with a cable to each anchoring member 16,

[0169] - pulling up the float member with the cable and threading the cable through the jacking towers 15,

[0170] - repeating the previous step for each jacking tower 15,

[0171] - pulling the cable until the anchoring members 15 engage with the jacking members (not shown) of each jacking tower 15,

[0172] - simultaneously using the jacking members (not shown) of the jacking towers 15 to tighten the vertical anchoring members 16 to sink the floating wind turbine foundation F into its working position.

[0173] Figures 5A-5B A further anchoring system for a floating offshore wind turbine foundation F according to Figures 4A-4C is shown, wherein the anchoring system in this embodiment is a single point anchoring system and comprises a mooring member 16. The mooring member 16 is connected to the outer float 2 by one of its ends and to an anchoring piece 17 arranged on the seabed by its opposite end.

[0174] The anchoring piece 17 comprises a rotating device (not shown), which allows the floating offshore wind turbine foundation F to rotate around the anchoring piece 17 when the direction of the wind, the water flow and / or the waves changes.

[0175] The mooring members 16 comprise one or more mooring lines, wherein each mooring line can be arranged to be rigid in order to avoid entanglement of one or more power cables (not shown) from being able to resist at least some bending moments.

[0176] As the offshore floating wind turbine foundation F in the present embodiment is identical to the offshore floating wind turbine foundation F described according to Figures 4A-4C the offshore floating wind turbine foundation F will not be described again.

[0177] Figure 6 An alternative embodiment of the offshore floating wind turbine foundation F is shown according to Figures 5A-5B the offshore floating wind turbine foundation F in this embodiment comprises three outer members 2 in the form of pontoons, but the pontoons 2 have an oval shape or a "ship-shaped" shape. The remaining parts of the offshore floating wind turbine foundation F will be described according to Figures 5A-5B .

[0178] Furthermore, the offshore floating wind turbine foundation F also comprises an anchoring system comprising a (vertical) jacking tower 15 arranged on one of the outer pontoons 2 and one or more vertical anchoring members 16 (not shown) arranged below the outer pontoons 2. The jacking tower 15 comprises jacking members (not shown) for fastening the one or more vertical anchoring members 16 to a suitable pre-tensioned level.

[0179] The one or more vertical anchoring members 16 are connected to a respective anchor 17 arranged below the outer pontoons 2.

[0180] The jacking tower 15 is arranged to protrude a certain height above the outer pontoons 2, which height is such that a part of the jacking tower 15 will protrude above the water surface when the offshore floating wind turbine foundation F is submerged and anchored in its working position, see also Figure 4B .

[0181] The anchoring system in the present embodiment is a TLP system (tension leg platform system).

[0182] Then, when anchoring the offshore floating wind turbine foundation F, the method for anchoring the offshore floating wind turbine foundation F described according to Figures 4A-4C can be used.

[0183] Figures 7A-7B An alternative embodiment of the offshore floating wind turbine foundation F according to the present application is shown, wherein the offshore wind turbine foundation F comprises three outer members 2 arranged around a central pontoon 1, said outer members 2 being in the form of nodes, and the three outer nodes 2 are arranged in an equilateral triangle at equal intervals.

[0184] The tower T extends upwards from the central buoy 1, wherein the tower T is either an integral part of the central buoy 1 or a separate unit connected to the central buoy 1 in a suitable manner.

[0185] The rotor-nacelle assembly 6 with the plurality of blades 7 is connected to the top of the tower.

[0186] The central buoy 1 has a circular shape, but it should be understood that the central buoy 1 can also have other shapes, such as a polygonal shape, an elliptical shape, etc.

[0187] The support structure 3 is connected to the lower end of the central buoy 1, wherein the support structure 3 is connected to the central buoy 1 by means of welding or bolting, for example. However, it should be understood that the support structure 3 can also be an integral part of the central buoy 1.

[0188] The support structure 3 comprises a central portion 3A and three arms 3B extending outwards from the central portion 3A of the support structure 3, wherein the three arms 3B are arranged at equal intervals around the central portion 3A of the support structure 3 or the periphery of the central buoy 1.

[0189] Furthermore, each of the three “arms” 3B will taper from the proximal end of the arm 3B, i.e. the end connected to the central portion 3A of the support structure 3 or the central buoy 1, to the distal end of the arm 3B, i.e. the end to be connected to the beam 4C.

[0190] In the present embodiment, the central buoy 1 is connected to each of the three outer nodes 2 by means of the support structure 3 and a plurality of beams 4B, respectively, wherein the plurality of beams 4B are arranged to form a plurality of pairs of beams 4C.

[0191] The pairs of beams 4C are then arranged between the support structure 3 connected to the central buoy 1 and the respective outer node 2, wherein the beams 4B in the pairs of beams 4C are arranged to taper from the support structure 3 to the outer node 2 to which the beam 4B is connected. This will result in the beams 4B being arranged such that the distance between the proximal ends of the beams 4B connected to the support structure 3 is greater than the distance between the distal ends of the beams 4B connected to the outer nodes 2.

[0192] In the present embodiment, the arms 3B extending outwards from the central portion 3A of the support structure 3 have a length such that the beams 4B in the pairs of beams 4C will form an “angled line” between two adjacent outer nodes 2.

[0193] Furthermore, the beams 4B in the pairs of beams 4C are arranged such that the centre lines of the beams 4B do not cross each other between the support structure 3 and the respective outer node 2, but rather the distal ends of the beams 4B in the pairs of beams 4C are arranged to be close to or abutting each other.

[0194] If the beams 4B are considered to be extended, the centre lines of the beams 4B in the pair of beams 4C will have an imaginary intersection point located within the circumference of the outer nodes 2.

[0195] In an embodiment, the imaginary intersection point can be arranged within a circle 30 having a radius which is less than 1 / 3 of the circumferential radius of the outer nodes 2, wherein the circle 30 is arranged concentrically with the outer nodes 2.

[0196] Furthermore, a plurality of struts 5 are provided between the central buoy 1 and the pair of beams 4C, wherein one of the struts 5 is arranged to extend from the outer nodes 2 to an upper end portion of the central buoy 1.

[0197] The struts 5 are beams, tubes or similar forms of rigid members.

[0198] Furthermore, the struts 5 are arranged as flexible bendable pre-tensioned structural members.

[0199] The offshore floating wind turbine foundation F further comprises an anchoring system, wherein the anchoring system comprises a (vertical) jacking tower 15 connected to each of the outer nodes 2 and a plurality of vertical anchoring members 16. Each jacking tower 15 comprises a jacking member (not shown) for tightening the plurality of vertical anchoring members 16 to a suitable pre-tensioning level.

[0200] The plurality of vertical anchoring members 16 are connected to a corresponding anchor 17 arranged below each of the outer nodes 2.

[0201] Furthermore, the jacking towers 15 are arranged to protrude a certain height above the outer nodes 2, which height is such that a portion of the jacking towers 15 will protrude above the water surface when the offshore floating wind turbine foundation F is submerged and anchored in its working position.

[0202] The anchoring system in the present embodiment is a TLP system (tension leg platform system).

[0203] Then, when the offshore floating wind turbine foundation F is anchored, the information about the Figures 4A-4C method for anchoring the offshore floating wind turbine foundation F can be used.

[0204] Furthermore, the offshore floating wind turbine foundation F can be transported to its installation position with the pair of beams in the water surface position, in a similar manner as described in relation to the Figure 4A embodiment described.

[0205] When the offshore floating wind power generator foundation F is in the installation position, the jacking towers 15 will simultaneously be used for tensioning all the vertical anchoring members 16 to sink the floating wind turbine foundation F into its working position, as Figures 7A-7B illustrated.

[0206] Figures 7A-7BThe floating wind turbine foundation F is shown in its working position, with the outer nodes 2 fully submerged and only a part of the jacking tower 15 extending above the water surface, the floating wind turbine foundation F being anchored to the seabed by a plurality of vertical anchoring members 16.

[0207] Even though the above described embodiments of the offshore floating wind turbine foundation are shown with one or two A-shaped frames, it should be understood that embodiments shown using for example one lower A-shaped frame can comprise an upper A-shaped frame (i.e. two A-shaped frames) or only one upper A-shaped frame (i.e. instead of a lower A-shaped frame), or embodiments shown using two A-shaped frames (i.e. an upper A-shaped frame and a lower A-shaped frame) can comprise an upper A-shaped frame or a lower A-shaped frame, thereby allowing each embodiment to be equipped with an upper A-shaped frame, a lower A-shaped frame or two A-shaped frames (i.e. an upper A-shaped frame and a lower A-shaped frame).

[0208] Figures 8A-8C A further alternative embodiment of the offshore floating wind turbine foundation F according to the present application is shown, wherein the offshore floating wind turbine foundation F is shown in a perspective view, a side view and a top view.

[0209] The offshore floating wind turbine foundation F comprises two (outer) members 2 in the form of nodes and a central buoy 1, which are arranged in an equilateral triangle with equal spacing.

[0210] A tower T will extend upwards from the central buoy 1, wherein the tower T is an integral part of the central buoy 1 or a separate unit connected to the central buoy 1 in a suitable manner.

[0211] A rotor-nacelle assembly 6 with a plurality of blades 7 is connected to the top of the tower.

[0212] The central buoy 1 has a circular shape, but it should be understood that the central buoy 1 can also have other shapes, for example a polygonal shape, an elliptical shape, a "ship shape" or the like.

[0213] A support structure 3 is connected to the lower end of the central buoy 1, for example by means of welding or bolting. However, it should be understood that the support structure 3 can also be an integral part of the central buoy 1.

[0214] The support structure 3 comprises a central portion 3A and three arms 3B extending outwardly from the central portion 3A of the support structure 3, wherein the three arms 3B are arranged at equal spacing around the central portion 3A of the support structure 3 or the circumference of the central buoy 1.

[0215] Furthermore, each of the three arms 3B will have a tapered form from the proximal end of the arm 3B, i.e. the end connected to the central part 3A of the support structure 3 or the central buoy 1, to the distal end of the arm 3B, i.e. the end to be connected to the end of the beam 4C.

[0216] In the present embodiment, the central buoy 1 forms pairs of beams 4C with each of the two outer nodes 2 via the support structure 3 and a plurality of beams 4B arranged to form the pairs of beams 4C.

[0217] The pairs of beams 4C are then arranged to extend between the support structure 3, connected to the central buoy 1, and the respective outer node 2, wherein the beams 4B in the pairs of beams 4C are arranged to taper from the support structure 3 towards the outer node 2 to which the beam 4B is connected. This will result in the beams 4B being arranged such that the distance between the proximal ends of the beams 4B connected to the support structure 3 is greater than the distance between the distal ends of the beams 4B connected to the outer nodes 2.

[0218] In the present embodiment, the arms 3B extending out from the central part 3A of the support structure 3 have a length such that the beams 4B in the pairs of beams 4C will form an “angled line” between two adjacent outer nodes 2.

[0219] Furthermore, the beams 4B in the pairs of beams 4C are arranged such that the centre lines of the beams 4B do not cross each other between the support structure 3 and the respective outer node 2, but rather the distal ends of the beams 4B in the pairs of beams 4C are arranged to be close to or abutting each other.

[0220] If the beams 4B are considered to be extended, the centre lines of the beams 4B in the pairs of beams 4C will have an imaginary intersection point located within the circumference of the outer node 2.

[0221] In embodiments, the imaginary intersection point can be arranged within a circle having a radius less than 1 / 3 of the circumferential radius of the outer node 2, wherein the circle is arranged concentrically with the outer node 2.

[0222] Furthermore, a plurality of struts 5 are arranged between the central buoy 1 and the pairs of beams 4C, wherein one strut 5 is arranged to extend from the outer node 2 to the upper end of the central buoy 1.

[0223] The struts 5 are beams, tubes or similar forms of rigid members.

[0224] Furthermore, the struts 5 are arranged as flexible bendable pre-tensioned structural members.

[0225] The offshore floating wind turbine foundation F further comprises an anchoring system, wherein the anchoring system comprises a (vertical) jacking tower 15 connected to each of the outer nodes 2 and a plurality of vertical anchoring members 16. Each jacking tower 15 comprises a jacking member (not shown) for fastening the plurality of vertical anchoring members 16 to a suitable pre-tensioning level.

[0226] The plurality of vertical anchoring members 16 are connected to a corresponding anchor 17 arranged below each outer node 2.

[0227] Further, the jacking tower 15 is arranged to protrude a certain height above the outer nodes 2, which height is such that when the offshore floating wind turbine foundation F is submerged and anchored in its operational position, a part of the jacking tower 15 will protrude above the water surface.

[0228] The anchoring system in this embodiment is a TLP system (tension leg platform system).

[0229] Then, when the offshore floating wind turbine foundation F is anchored, the information about Figures 4A-4C The method for anchoring the offshore floating wind turbine foundation F described.

[0230] Figures 9A-9D A support and transport frame S for an offshore floating wind turbine foundation F according to the present invention is shown, wherein the support and transport frame S can be used for supporting the offshore wind turbine foundation F, for example, during manufacturing or storage of the offshore wind turbine foundation F, or during transport of the offshore wind turbine foundation F, for example, from a quayside area to a vessel which is used for transporting the offshore wind turbine foundation from a manufacturing site to an area closer to the final installation area, or to a diving barge or vessel as part of a float-off operation.

[0231] During transport of the offshore wind turbine foundation F, a plurality of self-propelled multi-wheeled trailers (SPMTs) V can be used.

[0232] The support and transport frame S is built around a vertically arranged central pipe 12 which has substantially the same diameter as the central buoy 1. A flange connection can be provided between the pipe 12 and the central buoy 1 to transfer the weight of the wind turbine foundation (F) to the support and transport frame S. Heavy duty box beams 11, 13A are welded to the vertically arranged central pipe 12. Heavy duty outer beams 10 are welded to the heavy duty box beams 11, 13A. Lower height secondary beams 13B are welded between the heavy duty box beams 11, 13A and the heavy duty outer beams 10. Due to the lower height of the secondary beams, sufficient vertical space is arranged allowing self-propelled multi-wheeled trailers (SPMTs) to be positioned underneath the secondary beams 13B, allowing load transfer between the support and transport frame and the SPMTs.

[0233] The support and transport frame S is arranged to support and transport the offshore floating wind turbine foundation F during a transport phase on a vessel and / or a loading phase onto a vessel or a diving ship or a barge.

[0234] Furthermore, the outer profile element 10 and the inner profile element 11A are interconnected by a plurality of laterally extending beam elements 13.

[0235] The height of the laterally extending beam elements 13B is lower than the outer and inner profile elements 10, 11, 13A, thereby providing a space between the ground and the upper surface of the support and transport frame S, such that a plurality of self-propelled multi-wheeled trailers V can be used to lift and transport the support and transport frame S.

Claims

1. A floating offshore wind turbine foundation (F), the floating offshore wind turbine foundation (F) comprising: -Central buoy (1); - At least two outer components (2) arranged around the central buoy (1); as well as - A tower (T) arranged to extend upward from the central buoy (1), wherein the tower (T) is a component of the central buoy (1) or a separate unit appropriately connected to the central buoy (1), wherein the tower (T) is configured to attach a rotor-nacelle assembly (6) with blades. - Multiple beams (4A, 4B), The plurality of beams (4A, 4B) are arranged to form a plurality of pairs of beams (4C) connecting the central buoy (1) and the at least two outer members (2), wherein the pairs of beams (4C) taper from the central buoy (1) toward each of the at least two outer members (2). Its features are, The paired beams (4C) include at least a pair of lower beams, wherein the central buoy (1) includes a support structure (3) extending outward from the central buoy (1), the support structure (3) connecting at least the paired lower beams to the central buoy, wherein the foundation (F) also includes diagonally arranged supports (5), which, when viewed from above, connect between the beams (4A, 4B) to the support structure (3) of the central buoy (1) or directly to the tower (T).

2. The offshore floating wind turbine foundation (F) according to claim 1, wherein, The support structure (3) includes a lower support structure and an upper support structure, wherein the paired beams (4C) further include a paired upper beam, wherein the lower support structure connects the paired lower beams and the upper support structure connects the paired upper beams, wherein, when viewed from above, the support column (5) is connected between the beams (4A, 4B) to the lower support structure or upper support structure of the central buoy (1), or directly to the tower (T).

3. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The outer component (2) is a buoy, a node, or a combination of a buoy and a node.

4. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The plurality of paired beams (4C) are arranged to be connected near the upper part of each of the outer members (2), or near the lower part of each of the outer members (2), or near both the upper and lower parts of each of the outer members (2).

5. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The outer buoy has a circular shape, square shape, rectangular shape, elliptical shape, parabolic shape, boat shape, or polygonal shape.

6. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The imaginary intersection of the centerlines of the far ends of the beams (4A, 4B) in each pair of beams (4C) lies within the perimeter of each outer buoy (2).

7. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The imaginary intersection of the centerlines of the far ends of the paired beams (4C) lies within a circle (30) with a radius less than 1 / 3 of the circumference radius (R) of the outer buoy (2), the circle (30) being arranged concentrically with the outer buoy (2).

8. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The proximal ends of the paired beams (4C) are connected to the support structure (3) of the central buoy (1).

9. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The outer components (2) are arranged in equilateral triangles at equal intervals.

10. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, A hydrodynamic damper device (20) is connected to the lower end of each outer buoy (2).

11. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The support (5) is a rigid component in the form of a beam or pipe.

12. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The support is arranged as a pre-tensioned structural member that can be flexibly bent, for example, the pre-tensioned structural member is a wire or rod.

13. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The offshore floating wind turbine foundation (F) also includes a trim / ballast system in which ballast water is connected between each outer buoy (2) and two opposing beams (4) or between opposing outer buoys (2).

14. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, In the offshore floating wind turbine foundation (F), at least the upper beam forms an upper A-shaped frame, or at least the lower beam forms a lower A-shaped frame, or both the upper beam and the lower beam form an A-shaped frame.

15. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The angle α between the beams in a pair is arranged in the range of 5 degrees to 55 degrees.

16. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The tower (T) is a component of the central buoy (1).

17. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The proximal ends of beams (4A, 4B) in each pair of beams (4C) are connected to the periphery of the central buoy (1).

18. The offshore floating wind turbine foundation (F) according to claim 17, wherein, The distance between the proximal ends of the beams (4A, 4B) in each pair of beams (4C) is less than the diameter (D) of the central buoy (1).

19. The offshore floating wind turbine foundation (F) according to claim 17, wherein, The distance between the proximal ends of beams (4A, 4B) in each pair of beams (4C) is greater than the diameter (D) of the central buoy (1).

20. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, At least one support column (5) is arranged to extend from at least one outer member (2) to the upper support structure (3) of the central buoy (1) or directly to the tower (T).

21. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The support column (5) is arranged as a pre-tensioned structural member that can be flexibly bent.

22. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The offshore floating wind turbine foundation (F) also includes an anchoring system.

23. The offshore floating wind turbine foundation (F) according to claim 22, wherein, The anchoring system comprises a single anchor on the seabed.

24. The offshore floating wind turbine foundation (F) according to claim 22, wherein, The anchoring system includes multiple tensioned vertical anchoring members connected between the offshore floating wind turbine foundation and anchors located on the seabed.

25. The offshore floating wind turbine foundation (F) according to claim 22, wherein, The anchoring system includes one or more jacking towers (15), multiple anchoring components (16), and anchors (17).

26. The offshore floating wind turbine foundation (F) according to claim 22, wherein, The anchoring system includes one or more mooring components (16) and anchors (17), the anchors (17) including a rotating device.

27. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, A support and transport frame (S) is constructed around a vertically arranged central pipe (12), the diameter of which is substantially the same as that of the central buoy (1). The support and transport frame (S) is arranged to support and transport the offshore floating wind turbine foundation (F) during the transport phase on the ship and / or the loading phase on the ship, submarine or barge.

28. The offshore floating wind turbine foundation (F) according to any one of the preceding claims, wherein, The outer component (2) is arranged to be partially above the water surface during towing and installation, and submerged below the water surface after installation.

29. The offshore floating wind turbine foundation (F) according to claim 25, wherein, The lifting tower (15) is arranged to protrude a certain height above the outer member (2), such that a portion of the lifting tower (15) protrudes above the water surface when the offshore floating wind turbine foundation (F) is submerged and anchored in its working position.

30. A method for anchoring a floating offshore wind turbine foundation (F), the method comprising the following steps: - Transport the offshore floating wind turbine foundation (F) to the installation site. - Connect multiple anchoring members (16) to corresponding anchors (17) arranged below each outer member (2), - To engage the anchoring member (15) with the lifting member (not shown) of each lifting tower (15), - Use the lifting components (not shown) of the lifting tower (15) to secure the vertical anchoring components (16) to immerse the floating wind turbine foundation (F) in its working position.

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