Floating wind turbine system and method

Abstract

The present disclosure, in one aspect, provides a system and method for accessing these ports by connecting the wind turbine in a sideways position during transport. Once past the obstacle and in deeper water, the turbine can be erected into an upright configuration. The system comprises a hull assembly including a plurality of outer columns, including a first outer column, a second outer column, and a third outer column, the plurality of outer columns circumscribing a central axis Y and being equally spaced about the central column.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a non-provisional application of and claims the benefit of U.S. Provisional Application No. 63 / 276,082, entitled "SELF-UPENDING FLOATING WIND PLATFORM SYSTEMS AND METHODS," filed November 5, 2021, with Attorney Docket No. 0105198-037PRO, which is hereby incorporated by reference in its entirety for all purposes.

[0002] This application is a regular application of and claims the benefit of U.S. Provisional Application No. 63 / 276,086, filed November 5, 2021, entitled "DOWNWIND FLOATING WIND TURBINE AND ITS CONTROL SYSTEM," bearing Attorney Docket No. 0105198-038PRO, which is hereby incorporated by reference in its entirety and for all purposes. Summary of the Invention [Means for solving the problem]

[0003] One advantage of deploying some embodiments of floating wind turbines offshore over fixed-bottom wind turbines is that such floating wind turbines can be assembled and commissioned on land using cranes and machinery, and then towed to the site. However, access to many ports around the world can be hindered by bridges or other obstacles (e.g., airport regulations) that may limit how high a structure can rise above sea level (called "air draft"). Much of the world's existing infrastructure has been driven by the global shipping industry, which has standardized ship classes (e.g., PANAMAX, CHINAMAX, etc.). In some instances, air draft tolerances can be 50-70m. Some wind turbines can have hub heights of over 100m, making them inaccessible to many large ports or shipyards.

[0004] The present disclosure, in one aspect, provides systems and methods for accessing these ports by coupling the wind turbine in a sideways position during transport. Once past the obstacle and in deeper water, the turbine can be erected into an upright configuration. Additionally, many ports may have low draft limits, which may be between 7m and 8m. By transporting the wind turbine in a sideways position, the draft can be reduced in various embodiments.

[0005] Another advantage of some examples described herein is that loads on the wind turbine and floating hull structure may be reduced during extreme wind or disturbance events. In some embodiments, the turbine tower may be coupled into a sideways (or near sideways) position by high winds or by the incorporation of motors, actuators, etc. When the turbine is in such a position, loads on the turbine and floating hull may be reduced. In some examples, during a disturbance event of the turbine, the forces from the turbine may not be directly transferred to the hull. Instead, various embodiments may dissipate energy through viscous damping of the turbine substructure.

[0006] Current wind turbines can be robust on land and fixed offshore wind platforms, but when used on floating platforms, they usually require complex control systems or large platforms. These platform control systems are costly to install and difficult to maintain and operate because they require regular maintenance. In some wind turbines, the rotor is tilted upwards by 4 to 8 degrees to increase the clearance between the tips of the blades and the tower during operation. This angle to the horizontal is called the shaft axis, since the main axis of the wind turbine is from the generator or gearbox to the hub to transmit the torque from the rotor.

[0007] Wind turbines described in various embodiments of the present disclosure include downwind turbines in which the rotor is oriented 4-8 degrees above horizontal to increase the clearance between the tips of the blades and the tower during operation. Various example wind turbines generate thrust to generate power from the wind. The thrust may create an overturning moment on the platform, which may result in an average heel angle on the platform, where the heel angle may be the average pitch angle of the platform in the direction of the wind.

[0008] In some examples of floating wind platforms, the target design heel angle is the heel angle of the platform when the platform is subjected to the rated thrust of the turbine. Generally, the rated thrust is the maximum average thrust on the turbine during operation. The design heel angle of the platform may be determined by the restoring forces of the platform and mooring system. The restoring forces may be a function of the center of gravity and buoyancy of the platform, the surface moment of inertia area, and the restoring forces due to the mooring system. In general, increasing the hydrostatic stiffness of the platform may increase the cost or complexity of the system, or both. For example, for a conventional semi-submersible floating wind platform, the hydrostatic stiffness can be increased by increasing the spacing of the columns, increasing the size of the columns, or both. Wind platforms without an active platform control system may have a design heel angle of 4-5 degrees, resulting in a maximum rotor misalignment deviation of 8-13 degrees from horizontal. In various embodiments, the power output of the turbine is a function of the swept area of ​​the rotor. The swept area decreases as a function of the tilt angle of the turbine as a function of the cosine of the tilt angle (gamma). Mathematically,

[0009] P=.5*rho*Cp*A*cos(gamma)*V^3

[0010] where rho is the air density, Cp is the power coefficient, A is the swept area of ​​the blade, gamma is the turbine tilt angle, and V is the wind speed.

[0011] Some embodiments include floating downwind fixed hub turbines that operate passively at a mean heel angle. For example, thrust is generated to generate power, and such thrust may cause the platform to pitch (tilt) into the wind. For example, designing a floating wind turbine with a mean heel angle of 10 degrees will, in various embodiments, result in the same rotor misalignment (+ / - 5 degrees) as a vertically oriented upwind turbine, such as one on land. For example, designing a platform with a mean heel angle of 15 degrees will result in the same rotor misalignment as an upwind turbine on a floating platform with a heel angle of 5 degrees.

[0012] Some embodiments include floating downwind teetered turbines that operate passively at a mean heel angle. For example, in various embodiments, a floating wind turbine may be designed with a mean heel angle of 15 degrees, resulting in less rotor misalignment than a vertically oriented upwind turbine (e.g., 0 degrees vs. +5 degrees).

[0013] Some wind platforms with active platform control systems can set the design heel angle to 5-8 degrees, thus keeping the tower vertical and maintaining a maximum rotor misalignment of 4-8 degrees. Some wind turbines may be equipped with larger active control systems, which can result in a larger heel angle and a rotor misalignment of 0 degrees. However, there is a need for improved floating dedicated wind turbines and control methods to overcome the aforementioned obstacles and deficiencies in some examples of wind turbine systems.

[0014] In various embodiments, an advantage of an adjustable downwind floating wind turbine operating at a tilt angle is that it can push down the wake generated by the floating wind turbine, reducing the impact on downstream floating wind turbines where multiple floating wind turbines are arranged in an array, group, or farm. In various embodiments, this can allow more floating wind turbines to be packed into a given area, which can be of great interest to floating wind turbine operators and other stakeholders (such as the fishing industry). [Brief description of the drawings]

[0015] [Figure 1a] FIG. 1 illustrates a first side view of an example embodiment of a floating wind turbine.

[0016] [Figure 1b] FIG. 1b is a second side view of the example embodiment of the floating wind turbine of FIG.

[0017] [Figure 2a] FIG. 2 is a first side view of another example embodiment of a floating wind turbine.

[0018] [Figure 2b] FIG. 1b is a second side view of the example embodiment of the floating wind turbine of FIG.

[0019] [Diagram 3] 1 is a perspective view of a further example embodiment of a floating wind turbine hull and tower; FIG.

[0020] [Figure 4] FIG. 1 is a side view of a floating wind turbine in a substantially horizontal or non-vertical configuration.

[0021] [Diagram 5] FIG. 1 is a side view of an articulated tug barge with retractable ram according to an embodiment.

[0022] [Figure 6] FIG. 1 illustrates a top perspective view of a rigid arm single point mooring (SPM) buoy system according to an embodiment.

[0023] [Figure 7] FIG. 1 is a perspective view of a nacelle containing a wind turbine with three turbine blades.

[0024] [Figure 8] 1 illustrates an example embodiment of a free-standing floating wind turbine in an upright (e.g., operational) configuration.

[0025] [Figure 9] FIG. 9 is a close-up view of the lower part of the floating wind turbine of FIG. 8.

[0026] [Figure 10] 1 illustrates an example embodiment of a free-standing floating wind turbine in a folded (e.g., transportation) configuration.

[0027] [Figure 11] 1 illustrates an example embodiment of a free-standing floating wind platform during an erection operation.

[0028] [Figure 12] 1 shows another example embodiment of a floating wind turbine with three outer columns.

[0029] [Figure 13a] An example of an upwind type floating wind turbine is shown, in which the central axis Y of the tower has a heel angle of 0° and the rotor tilt angle is 5°.

[0030] [Figure 13b] FIG. 13a shows an upwind floating wind turbine with a heel angle of 10°.

[0031] [Figure 14a] An example of a downwind floating wind turbine is shown, in which the central axis Y of the tower has a heel angle of 0° and the rotor tilt angle is 5°.

[0032] [Figure 14b] FIG. 14a shows a downwind floating wind turbine with a heel angle of 10°.

[0033] [Figure 15] 1 shows an example of a downwind floating wind turbine with a teetered rotor.

[0034] [Figure 16] FIG. 1 is a block diagram of a wind turbine controller method.

[0035] [Figure 17a] An example embodiment of a downwind floating wind turbine under static conditions with a static tilt angle of 5° and a heel angle of 0° is shown, which results in a 0.4% reduction in annual energy production (AEP) compared to the case with a tilt angle of 0°.

[0036] [Figure 17b] An example embodiment of a passive downwind floating wind turbine is shown under rated thrust conditions with a static pitch angle of 5° and a heel angle of 10°, resulting in a rotor misalignment of -5°, which results in a 0.4% reduction in AEP compared to a rotor misalignment of 0°.

[0037] [Figure 18a] An example embodiment of an upwind floating wind turbine under static conditions with a static pitch angle of 5° and a heel angle of 0° is shown, which shows a 0.4% reduction in AEP compared to the case with a pitch angle of 0°.

[0038] [Figure 18b] An example embodiment of a passive upwind floating wind turbine is shown under rated thrust conditions with a static pitch angle of 5° and a heel angle of 5°, thus resulting in a rotor misalignment of 10°, which in this example causes an acceptable AEP reduction of 1.5% compared to a rotor misalignment of 0°.

[0039] [Figure 18c] An example embodiment of a passive upwind floating wind turbine is shown under rated thrust conditions resulting in a static pitch angle of 5° and a heel angle of 10°, thus resulting in a rotor misalignment of 15°, which in this example causes an unacceptable AEP reduction of 3.4% compared to the case where the rotor misalignment is 0°. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] It should be noted that the drawings are not drawn to scale, and that elements of similar structure or function are generally represented by similar reference numerals throughout the drawings for illustrative purposes. It should also be noted that the drawings are intended only to facilitate the description of the preferred embodiments. The drawings do not illustrate every aspect of the described embodiments, and are not intended to limit the scope of the present disclosure.

[0041] Described below are example systems and methods that can be used to design lighter, less expensive floating wind turbines, including towers and supporting hull platforms, according to some embodiments. For example, various embodiments may include floating wind turbines that include one or more of the following:

[0042] (1) Wind turbines with one, two or three blades (e.g., horizontal axis: upwind or downwind rotors, or vertical axis).

[0043] (2) A platform comprised of multiple buoyant assemblies (e.g., four assemblies). For example, in some embodiments, the assemblies may include a four-bar linkage using members connected by pin bearings or other suitable elements. Some example assemblies include a primary buoyant member (e.g., a pillar). In one embodiment, each assembly is connected to a central pillar.

[0044] (3) A movable truss member for each assembly, such that each assembly can be reconfigured depending on the position of the truss member. In various examples, once the truss members are connected, the final position of the assembly is determined. In one embodiment, the final position of the assembly is such that the columns are oriented vertically.

[0045] In one embodiment, the platform may be designed as shown in Figure 8. Such a design may include, consist essentially of, or consist of one or more of the following elements, although in some embodiments one or more of such elements may be specifically absent.

[0046] (a) Multiple buoyant columns that may have variable mass (such as partially or completely filled ballast tanks).

[0047] (b) A plurality of independent assemblies, in which the horizontal members (e.g., the upper and lower truss members of FIG. 8) form a four-bar linkage with the center column and the buoyant structure (e.g., the outer columns). In some examples, each structural member may be connected by pin bearings.

[0048] (c) One or more pinned structural diagonal cross beams.

[0049] (d) A mechanism that allows the ends of the cross beams to pass through the central column / tower.

[0050] One embodiment includes, consists essentially of, or consists of a floating downwind turbine with a turbine control system that can be used to optimize the pitch angle of the platform.

[0051] Another embodiment comprises, consists essentially of, or consists of a floating downwind turbine with a teetered hub and a turbine control system that can be used to optimize the rotor teeter angle and platform tilt angle.

[0052] In some such embodiments, there is no active control system on the platform as it is allowed to passively pitch or tilt into the wind direction, but in various examples the rotor plane can remain aligned horizontally so the turbine can generate maximum power.

[0053] 1a, 1b, 2a, and 2b, two example embodiments 100A, 100B of a floating wind turbine 100 are shown in FIGS. 1a and 1b, and 2a and 2b, respectively. The floating wind turbine 100 is shown comprising a tower body 110 having a tower shaft 112 extending along an axis Y. The tower body 110 further comprises a tower base 114 at a lower end of the tower shaft 112, with a keel plate 116 disposed at a lower distal end of the tower body 110. One or more fins 118 may extend between the keel plate 116 and the tower base 114 to enhance the connection between the keel plate 116 and the tower base 114 and / or to reduce rotation, movement, or pitch of the tower 110.

[0054] A nacelle 170 can be located on top of the tower body 110. The nacelle 170 can be configured in a variety of suitable ways and can include a variety of suitable elements, including a wind turbine 700 with a hub 172 having a number of blades 174 extending therefrom, as shown in the example of Figure 7. Further embodiments can include any suitable number of blades 174, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 16, 24, 36, 48, etc. In some embodiments, the wind turbine 700 can operate on a horizontal axis with an upwind or downwind rotor, or can operate on a vertical axis.

[0055] The example of Figure 7 should not be construed as limiting, as various embodiments may include any suitable turbine element. Additionally, while various embodiments herein relate to wind turbines, it will be apparent that further embodiments may be employed for a variety of suitable purposes, including lighthouses, bridges, communication arrays, weather stations, observation stations, weapon mounts, and the like.

[0056] 1a, 1b, 2a, and 2b, the floating wind turbine 100 is further shown to comprise a hull 130 including a pair of base elements 132 and a pair of support architectures 134 spaced apart and coupled to one another via one or more bars 136. As shown in the example of Figures 1b and 2b, the pair of base elements 132A, 132B, the pair of support architectures 134A, 134B, and the one or more bars may define a hull cavity 138.

[0057] A pitch plate 140 may extend between the support architectures 134A, 134B and be rotatably coupled to the hull 130 via a pitch shaft 142, thereby allowing the pitch plate 140 to rotate about an axis X. The tower shaft 112 and / or the tower base 114 may extend through and be coupled to the pitch plate 140, thereby allowing the tower 110 to rotate about an axis X via the pitch plate 140. In various embodiments, the axis Y of the tower 110 may be perpendicular to and / or coincident with the axis X. As shown in the examples of FIGS. 1a, 1b, 2a, and 2b (and also in the example of FIG. 3, which is described in more detail herein), such rotation of the tower 110 via the pitch plate 140 may allow the tower base 114 and / or the keel plate 116 to swing or pitch within the hull cavity 138 to various configurations described herein.

[0058] Additionally, the tower 110 may be coupled to the pitch plate 140 via a yaw bearing 144, which may allow the tower shaft 112 and / or tower base 114 to rotate about the axis Y of the tower 110. In some embodiments, rotating the tower 110 about the axis Y may be desirable to position the nacelle 170 in a desired or optimal orientation, such as an angle at which the wind turbine 700 associated with the tower 110 generates the maximum amount of energy, an angle at which the blades 174 generate the maximum amount of energy without compromising the structural integrity of the blades 174, an angle that protects the blades 174 from wind damage, etc. Additionally, in some embodiments, the nacelle 170 may be rotatably coupled to the top of the tower 110 in addition to or instead of the yaw bearing 144. In some embodiments (e.g., downwind turbine embodiments), there may or may not be a yaw motor or actuator that actively drives the yaw rotation of the tower 110 about the central axis Y. In some examples, the wind turbine's anemometer may be downwind and a yaw bearing 144 may allow passive rotation of the tower 110 relative to the hull 130. In another embodiment, a conical bearing may allow free yaw motion of the tower 110 while splitting the hull 130 (e.g., as shown in Figures 1a, 1b, 2a, and 2b).

[0059] In an upwind turbine embodiment, the yaw bearing 144 may replace the need for a yaw controller in the nacelle 170. In one such embodiment, a motor may drive the yaw bearing 144 so that the nacelle 170 points upwind. In this configuration, in some examples, it may be desirable for the axis X of the pitch shaft 142 to be perpendicular to the direction of the incoming wind to minimize off-axis loads on the bearings or other elements of the floating wind turbine 100.

[0060] The floating wind turbine 100 may be configured to be positioned floating on the surface 101 of a body of water 102, with a portion of the floating wind turbine 100 positioned within the body of water 102 and a portion of the floating wind turbine 100 positioned above 103 the body of water 102. For example, in the embodiments 100A, 100B of Figures 1a, 1b, 2a, and 2b, the nacelle 170, tower shaft 112, pitch plate 140, pitch shaft 142, yaw bearing 144, and axis X are shown positioned above 103 the surface 101 of the body of water 102. The tower base 114 and a portion of the support architecture 134 are shown partially above 103 and within the body of water 102. The base element 132 of the hull 130 and the keel plate 116 of the tower 110 are shown below the surface 101 of the body of water 102. The floating wind turbine 100 may be located in any suitable body of water or fluid, including an ocean, a lake, a river, an artificial body of water, or the like.

[0061] Further embodiments may be configured to position various elements of the floating wind turbine 100 in various suitable positions relative to the surface 101 of the body of water 102 on which the floating wind turbine 100 floats, and the examples of Figures 1a, 1b, 2a, and 2b should not be construed as limiting. Additionally, as described herein, the buoyancy of the floating wind turbine 100 may be altered in various embodiments, which may change which elements are above 103 or within the body of water 102 at a particular time. In some embodiments, it may be desirable to position elements such as at least a portion of the tower base 114 and the keel plate 116 within the body of water 102 to provide resistance to or damping of rotation of the tower 110.

[0062] For example, in some embodiments, one or more fins 118 have a plane parallel to the axis of rotation X that can provide a surface area that provides resistance to or damping of rotation of tower 110 based on friction between such surface area and the water 102 about which fins 118 of tower 110 rotate. Additionally, in some embodiments, it may be desirable to position elements such as pitch plate 140, pitch shaft 142, and / or yaw bearing 144 above surface 101 of water 102 to prevent or reduce water ingress, corrosion, and the like of such elements.

[0063] In various embodiments, it may be desirable to fix or substantially fix the floating wind turbine 100 in position on the surface 101 of the water surface 102. For example, it may be desirable to prevent the floating wind turbine 100 from drifting or from contacting undesirable objects such as another floating wind turbine 100 (e.g., in a wind farm), a reef, a shore, a rock, a cliff, etc. In various embodiments, including the examples of Figures 1a, 1b, 2a, and 2b, one or more mooring lines 150 may be coupled to the floating wind turbine 100 to fix or substantially fix the floating wind turbine 100 in position. For example, such one or more mooring lines 150 may be coupled to various suitable locations on the hull 130, such as the support architecture 134 (see Figures 1a and 1b), the base element(s) 132 (see Figures 2a and 2b), etc. In some examples, the mooring lines 150 may be connected to a weight or anchor on the ocean bottom, lake bottom, river bed, or the like.

[0064] In some embodiments, the floating wind turbine 100 can be connected to a turret system, such as a floating production storage and offloading unit (FPSO), or a single-point moored buoy. An example of such a moored buoy system 600 is shown in Figure 6. In some embodiments, such a turret system can be driven to rotate upwind or passively move the wind vane downwind.

[0065] In various embodiments, the floating wind turbine 100 can generate electrical power (e.g., via wind rotating the wind turbine 700, as shown in the example of FIG. 7), which can be transmitted to various locations via one or more electrical cables 155, which in various embodiments can extend from the bottom of the keel plate 116, as shown in FIGS. 1a and 1b. For example, in some embodiments, the electrical power generated by the floating wind turbine 100 can be transmitted to land, a battery station, another floating wind turbine 100, an on-water power consumer (e.g., a floating home, a ship, a station, etc.). Additionally, in some embodiments, the one or more electrical cables 155 can be configured to provide electrical power to the floating wind turbine 100, which can be received from land, a battery station, another floating wind turbine 100, etc.

[0066] 3, a portion of a further embodiment 100C of a floating wind turbine 100 is shown that includes a tower 110 rotatably coupled to a hull 130 via a pitch shaft 142. In this example embodiment 100C, the hull 130 can include one or more floater modules 334 that surround the tower 110 and one or more connectors 336 that extend between the floater modules 334. In some examples, the connectors 336 include hinged connections that strengthen the hull 130, but may allow the tower 110 to tip over, as described herein.

[0067] A yaw unit 344 may be disposed at the top of the hull 130, and a pair of pitch units may be disposed on the yaw unit 344, which may hold the pitch shaft 142 and allow the tower 110 to rotate via the pitch shaft 142. The floater module 334, the connector 336, and the yaw unit 344 may define a hull cavity 338 through which the tower 110 may extend and pitch or rotate via the pitch shaft 142. The yaw unit 344 may be configured to rotate such that the tower 110 can rotate about a central axis (e.g., axis Y shown in Figures 1a, 1b, 2a, and 2b). The hull 130 may further comprise one or more fairleads 350 that allow the mooring lines 150 to be coupled and secured to the floating wind turbine 100, as described herein.

[0068] In various embodiments, the base of the yaw unit 344 may include a float designed in a "C" shape that may allow for a 90 degree pitch rotation of the tower 110 of the floating wind turbine 100. In some embodiments, the connector 336 may be hinged, allowing the tower 110 to be coupled when the connector 336 is open, and may transfer loads across the structure of the hull 130 when the connector 336 is closed.

[0069] In some embodiments, a pitch bearing can be located on the tower 110, and the pitch shaft 142 can include a retractable ram that can decouple the tower 110 from the floating hull 130. In various examples, such an assembly can be used in an articulated tug-barge 500, as shown in FIG. 5. In another embodiment, the tower 110 can be connected to the hull 130 via a sliding joint. In some examples, an internal cable can be tensioned to tip the turbine. In one such embodiment, the floating hull 130 can be made into a more structurally efficient toroidal shape.

[0070] As discussed herein, in various embodiments, the pitch shaft 142 or the like may enable the tower 110 of the floating wind turbine 100 to assume a vertical or near-vertical configuration (e.g., for power generation) as shown in Figures 1a, 1b, 2a, and 2b, or a horizontal or near-horizontal configuration (e.g., for installation, transportation, offloading) as shown in Figure 4. For example, Figure 4 shows an embodiment 100A of the floating wind turbine 100 in which the central axis Y of the tower 110 is in a near-horizontal configuration and disposed along an axis Y1, and the tower 110 is configured to pitch an angle θ about the pitch shaft 142 to assume a vertical or near-vertical configuration in which the central axis Y of the tower 110 is disposed along an axis Y2. In various embodiments, the configuration or axis Y2 may be vertical or near-vertical with respect to gravity, the plane W of the surface 101 of the body of water 102 on which the floating wind turbine 100 floats, the main horizontal axis of the floating wind turbine 100, or the like.

[0071] In some embodiments, the floating wind turbine 100 may be configured to pitch or rotate from a vertical or near-vertical configuration (e.g., from axis Y2) by any suitable angle θ, including positive and / or negative 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, etc. For example, some embodiments may be configured to rotate in only one direction from a vertical or near-vertical configuration, or may be configured to rotate or pitch in both directions from a vertical or near-vertical configuration. In some embodiments, the maximum rotation in both directions may be the same or different (e.g., any of the example values ​​above). In some embodiments, tower 110 can be configured to pitch or rotate into a state that prevents tower 110, nacelle 170, or the wind turbine of nacelle 170 from extending into water 102 or contacting surface 101 of water 102, while in some embodiments, tower 110, nacelle 170, and / or the wind turbine of nacelle 170 can be configured to extend into water 102 or contact surface 101 of water 102.

[0072] In various embodiments, the rotation or pitch of the tower 110 may be configured based on the ability of the hull 130 to rotate, pitch, or move on the surface 101 of the water 102 as a result of forces such as waves, wind, storms, etc. In some examples, the orientation of the tower 110 may be actively controlled relative to the hull 130 such that the tower 110 may be maintained in a vertical or near-vertical configuration even as the hull 130 rotates, pitches, or moves on the surface 101 of the water 102. For example, the orientation of the tower 110 and / or the hull 130 may be monitored and determined relative to a desired vertical or near-vertical configuration, and motors, actuators, etc. may be used to actively change the orientation of the tower 110 toward the desired vertical or near-vertical configuration despite the rotation, pitch, or movement of the hull 130 on the surface 101 of the water 102.

[0073] An embodiment of a method for operating the floating wind turbine 100 may include determining an orientation of the tower 110 and / or the hull 130, determining whether the tower 110 is in an orientation other than a vertical or near-vertical configuration or within an error range of a vertical or near-vertical configuration based at least in part on the determined orientation of the tower 110 and / or the hull 130, and actuating the tower 110 (e.g., about the pitch shaft 142) to move the tower 110 towards a desired vertical or near-vertical configuration or within an error range of the desired vertical or near-vertical configuration. In some embodiments, such a method may be performed in real time, near real time, or every 0.25, 0.5, 0.75, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 10.0 seconds, etc.

[0074] A floating wind turbine 100 configured with the tower 110 in a horizontal, near horizontal, or non-vertical configuration may be desirable for operations such as installing the floating wind turbine 100, assembling the floating wind turbine 100, transporting the floating wind turbine 100, maintaining the floating wind turbine 100, and off-loading the floating wind turbine 100. For example, Figure 4 shows an example embodiment in which a tow line 410 is connected to the hull 130 of the floating wind turbine 100 and can be used to move the floating wind turbine 100.

[0075] Further, in some examples, if it is determined that wind or other weather conditions may cause damage to elements of the floating wind turbine 100 (e.g., blades 174, tower shaft 112, etc.), the tower 110 may be automatically or manually lowered to a horizontal, near horizontal, or non-vertical configuration to protect the floating wind turbine 100 from damage. For example, a method of operating the floating wind turbine 100 may include determining whether wind or weather conditions exceed or are predicted to exceed safety thresholds, and if so, lowering the tower 110 to a horizontal, near horizontal, or non-vertical configuration to protect the floating wind turbine 100. Such a determination may be made by one or more weather, wind, or other sensors provided on the floating wind turbine 100, another floating wind turbine 100, by a weather station, by a device on land, etc. In some embodiments, the computing device of the floating wind turbine 100 can make such determinations based on local and / or remote data, can automatically lower the tower 110 without user input, can alert a user to a hazard, can receive commands to lower the tower 110, etc. In some examples, the lowering of the tower 110 can be performed by a motor or other actuator, and in some examples, the tower 110 can be changed from a locked configuration to an unlocked configuration, which allows the tower 110 to fall or descend under its own weight.

[0076] In various embodiments, each portion of the floating wind turbine 100 can be configured to have or include a variable amount of mass or ballast. In some embodiments, a portion of the tower base 114 or a portion of the tower 100 below the pitch shaft 142 can be configured to have mass or ballast added or removed therefrom. For example, in various embodiments, the tower base 114 and / or the keel plate 116 can include a cavity into which ballast material (e.g., sand, weights, water, etc.) can be introduced or removed. In further embodiments, ballast or mass (e.g., weights, sandbags, water bags, etc.) can be coupled to or removed from the tower base 114 and / or the keel plate 116.

[0077] The addition of such ballast material can, in various examples, lower the center of gravity of the tower 110, such as from a first, higher center of gravity CG1 to a lower center of gravity CG2 as shown in FIG. 3. In various embodiments, the addition of such ballast material can lower the center of gravity of the tower 110 from above the pitch shaft 142 to below the pitch shaft 142 (see, e.g., FIG. 3), which can cause the tower 110 to rise or tend to rise from a horizontal, near horizontal, or non-vertical configuration (see, e.g., FIG. 4) to a vertical or substantially vertical configuration (see, e.g., FIGs. 1a, 1b, 2a, and 2b). In further embodiments, the addition of ballast can lower the center of gravity of the tower 110 from a first position above the pitch shaft 142 to a second position above the pitch shaft 142, or can lower the center of gravity of the tower 110 from a first position below the pitch shaft 142 to a second position below the pitch shaft 142.

[0078] A single floating wind turbine 100 or an array of multiple floating wind turbines 100 can be manufactured, erected, or positioned in a variety of suitable ways, with various portions being made on land and / or on the body of water 102. For example, in some embodiments, during manufacturing and / or assembly of the hull 130 and tower 110, the tower 110 can be in either a vertical or horizontal position. In one embodiment, the nacelle 170, wind turbine 700, and / or blades 174 can be coupled to the tower 110 in a horizontal or substantially horizontal position. In such embodiments in some examples, a smaller, more readily available crane can be used to lift the tower 110 or portions thereof along with the nacelle 170 and / or blades 174 of the wind turbine 700. In some examples, ballast (e.g., solid or liquid ballast) can be added to the tower base 114 before, during, or immediately after installation of the nacelle 170, wind turbine 700, blades 174, etc., to balance the weight of such elements. In one embodiment, the solid ballast may take the form of batteries. In some embodiments, the ballast may be added incrementally as additional elements are installed on the tower 110, nacelle 170, etc.

[0079] In one embodiment, the amount of ballast added can be calculated such that the vertical center of gravity of the tower 110 (including the nacelle 170, wind turbine 700, etc.) is located on or substantially located on the pitch axis X (see, e.g., FIGS. 1b and 2b). In such an embodiment (in the absence of friction), the weight of the turbine 700, tower 110, etc., does not impose an overturning moment on the hull 130. Such an embodiment can reduce the holding force required to keep the floating wind turbine 100 in a sideways, near sideways, or non-vertical position, and can also reduce the force required to rotate the tower 110 relative to the hull 130 (e.g., to or from a vertical or near vertical position).

[0080] In some embodiments, once the tower 110 is integrated (e.g., via the pitch shaft 142) into the hull 130 on or near land, in various examples, the assembled floating wind turbine 100 can be towed from the port to a location on the body of water 102 where the floating wind turbine 100 will be installed. Many ports have draft or air draft restrictions as previously mentioned, which may be the distance from the water surface 101 to the highest point of the vessel, the cargo on the vessel, or the cargo being towed by the vessel. Draft restrictions may be 7m, 8m, 9m, 10m, 12m or less, etc. Air draft restrictions may be 35m, 40m, 45m, 50m, 55m, 60m, 70m, 75m, 80m, 85m, 90m or less, etc. Once these obstacles or restrictions are cleared, the platform can be reconfigured to have a larger draft, or a larger air draft, or both a larger draft and a larger air draft.

[0081] In one embodiment, the tower base 114 and / or keel plate 116 may be filled with sand, gravel, soil, etc. at a location away from the port (e.g., after port obstructions and / or restrictions are cleared). This is because such materials may be readily available, low-cost solid ballast options. Furthermore, when it is necessary or desirable to return to port or land for maintenance operations and lower the tower 110, such ballast material may simply be dropped to the seabed, as needed, without harming the environment, which may allow the tower 110 to be lowered or more easily lowered. After maintenance operations, when the floating wind turbine 100 is reinstalled or installed at a new location on the body of water 102, new ballast may be added again to the tower 110 to raise or facilitate the raising of the tower 110, as described herein (e.g., the tower pitch motor may not be able to raise the tower without adding a sufficient amount of ballast).

[0082] In various embodiments, as additional ballast is added, the vertical center of gravity of the tower 110 may be lowered below the pitch axis X (see, e.g., FIG. 3). As a result, the wind turbine tower 110 may be raised to an upright or near-upright position. The floating wind turbine 100 may then be towed (e.g., via tow lines 410) to an offshore wind farm site so that it can be installed (e.g., connected to a mooring and / or cable system including mooring lines 150, electrical cables 155, etc.). In another embodiment, the floating wind turbine 100 may be towed with the tower 110 in a sideways, near-sideways, or non-upright position (e.g., as shown in FIG. 4) to reduce drag on the tower 110 and associated elements. In such an embodiment, tilting the turbine may be performed at the wind farm site (e.g., by adding ballast, pitch motors, a crane, etc.).

[0083] In various examples, the turbine 700 can be put into operation after the hull 130 is connected to a cable and / or mooring system. In an embodiment with an upwind horizontal axis wind turbine, the horizontal center of gravity of the tower 110 is located toward the hub 172 of the nacelle 170. A static overturning moment can occur, causing the turbine 700 to tilt into the wind. In some examples, the optimal static tilt angle to the wind can range from 5-15 degrees, 7-13 degrees, 9-11 degrees, 4-17 degrees, 3-19 degrees, 2-20 degrees, etc. For certain low wind speeds, the tilt angle of the turbine 700 can offset the tilt angle of the nacelle 170 in various embodiments, so that tilting the turbine 700 can increase power generation. For higher wind speeds, in some examples, the turbine 700 can tilt out of the wind direction.

[0084] In some embodiments, fins 118 can be added to the base 114 and / or keel plate 116 of the tower 110 to increase the viscous damping effect of the tilting tower 110. In the event of an emergency shutdown or other event that causes a dramatic change in thrust, the floating wind turbine 100 may exhibit large dynamic tilting motions. The fins 118, in some examples, can dissipate energy from the dynamic tilting motions into the surrounding fluid 102, thereby reducing the loads transferred to the hull 130.

[0085] As previously mentioned, when the floating wind turbine 100 is returned to port for maintenance, decommissioning, etc., the ballast in and / or on the keel plate 116 and / or tower base 114 may be removed. This may reduce the draft of the floating wind turbine 100, allowing it to enter ports with draft restrictions. Furthermore, when the vertical center of gravity is aligned with or close to the pitch axis X (e.g., based on the addition or removal of ballast), in various examples, the tower 110 may be moved to a sideways orientation without the need for a large tugboat.

[0086] Thus, a method of installing at least one floating wind turbine 100 may include one or more of the following steps, which may begin with assembling at least a portion of the tower 110 and hull 130 of the floating wind turbine 100, and then coupling the tower 110 to the hull 130 (e.g., via the pitch shaft 142). Some or all of such assembly may occur on land, including at a port or coastline, or on land away from a port or coastline. For example, the tower 110 and hull 130 (or portions thereof) may be transported as separate pieces to a port or coastline, and the tower 110 and hull 130 (or portions thereof) may be assembled to form a complete or substantially complete floating wind turbine 100.

[0087] Such a complete or substantially completed floating wind turbine 100 may be in a horizontal or near-horizontal configuration with the tower 110 during assembly and / or during part of the journey from the harbor or shoreline to the desired location where the floating wind turbine 100 will be installed. Where possible or desirable, the floating wind turbine 100 may be converted from a state in which the tower 110 is in a horizontal or near-horizontal configuration to an upright configuration in which the tower 110 is in a vertical or near-vertical configuration.

[0088] For example, as described herein, in some embodiments, erecting the tower 110 may include adding ballast in and / or on portions of the tower 110 to change the center of gravity of the tower 110, thereby allowing the tower 110 to be self-supporting or to be uprighted by a pitch actuator, crane, etc. In various embodiments, such methods, or portions thereof, may be performed in reverse if the floating wind turbine 100 needs to be decommissioned, repaired, lowered, or moved to prevent damage that may be caused by wind, weather, etc.

[0089] 8-11, another embodiment 100D of a floating wind turbine 100 is shown comprising a tower 110 coupled to a hull assembly 830 including a central column 840 and a number of outer columns 850 coupled to the central column 840 via one or more respective upper truss members 860, one or more respective lower truss members 870, and one or more respective cross beams 880. Note that for simplicity, elements such as the nacelle, rotor, turbine, etc. are not shown in these figures.

[0090] The tower 110 may include a tower shaft 112 having a central axis Y, and the central column 840 may be disposed at a lower end of the tower shaft 112 while sharing the central axis Y. As shown in the example of FIGS. 8 and 9, the floating wind turbine 100 may include four outer columns 850A, 850B, 850C, 850D spaced equidistantly from the central column 840 via upper and lower truss members 860, 870 and cross beams 880. In various embodiments, the outer columns 850 may have respective separate central axes parallel to the central axis Y of the tower 110 and the central column 840. In various embodiments, the outer columns 850 and / or the central column 840 may include ballast tanks configured to hold fluids, such as air and / or water, as described herein.

[0091] Additionally, the four outer pillars 850A, 850B, 850C, 850D may be equally spaced around the central pillar 840, with each adjacent outer pillar 850 spaced 90° apart from one another about the central axis Y. For example, the first and third outer pillars 850A, 850C may be disposed in a first common plane that is coincident with the central axis Y. The second and fourth outer pillars 850B, 850D may be disposed in a second common plane that is coincident with the central axis Y and perpendicular to the first common plane of the first and third outer pillars 850A, 850C.

[0092] Also, in various embodiments, the four outer columns 850A, 850B, 850C, 850D can be of equal length such that the bottoms of the four outer columns 850A, 850B, 850C, 850D are disposed in a third common plane and the tops of the four outer columns 850A, 850B, 850C, 850D are disposed in a fourth common plane that is parallel to the third common plane and perpendicular to the central axis Y. In some embodiments (e.g., a 10-15 MW turbine 700), the floating wind turbine can have a rotor diameter of 180-230 m. In various examples, the tower 110 can have a height of 100-150 meters. In various embodiments, the columns 840, 850 can have a diameter of 8-12 m. In some examples, the outer columns 850 may be 40-50 meters away from the central column 840 (e.g., the length of the upper and / or lower truss members 860, 870 may be 40-50 meters). In some examples, the height of the columns may be 30-40 meters. In various embodiments, the columns 840, 850 may have an operating draft of 15-25 m.

[0093] As shown in the example embodiment 100D of the floating wind turbine 100 in FIGS. 8-11, each outer column 850 can be connected to the central column 840 via a pair of upper truss members 860. For example, as shown in FIG. 9, a first outer column 850A can be coupled to the central column 840 via a first upper truss member and a second upper truss member 860A1, 860A2. In various embodiments, the pair of upper truss members 860 can extend from the top of the respective outer column 850 at an angle such that the distance between the pair of upper truss members 860 increases toward the central column 840. For example, such angles can be 2°, 4°, 6°, 8°, 10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°, 26°, etc., including ranges between such values. In various embodiments, the upper truss members 860 can be configured to extend toward the central column 840 in a common plane perpendicular to the central axis Y.

[0094] In various embodiments, the upper truss members 860 may be cylindrical bars as shown in the example embodiment 100D of the floating wind turbine 100 in Figures 8-11, however, in further embodiments, the upper truss members 860 may be any suitable shape, such as an I-beam, a box truss, etc. Additionally, in various embodiments, the number of upper truss members 860 associated with each outer column 850 may be any suitable number, such as 1, 2, 3, 4, 5, 10, 25, 100, etc. Additionally, various structures may be associated with the upper truss members 860, such as plates, walkways, etc.

[0095] As shown in the example embodiment 100D of the floating wind turbine 100 in Figures 8-11, each outer column 850 can be connected to the central column 840 via a lower truss member 870. For example, as shown in Figure 9, a first outer column 850A can be connected to the central column 840 via a first lower truss member 870A, a second outer column 850B can be connected to the central column 840 via a second lower truss member 870B, a third outer column 850C can be connected to the central column 840 via a third lower truss member 870C, and a fourth outer column 850D can be connected to the central column 840 via a fourth lower truss member 870D.

[0096] In various embodiments, the lower truss member 870 can include various suitable structures such as a plate and / or one or more bars (see, for example, FIGS. 9 and 10, which show a lower truss plate 872 covering a pair of lower truss bars 874). In some embodiments, when a pair of lower truss bars 874 extend from the lower ends of the respective outer columns 850, such lower truss bars can extend at an angle such that the distance between the pair of upper truss members 860 increases toward the central column 840. For example, such an angle can be 2°, 4°, 6°, 8°, 10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°, 26°, etc., including ranges between such values. In some examples, such an angle can be the same as the upper truss member 860. In various embodiments, the lower truss members 870 can be configured to extend toward the central column 840 in a common plane perpendicular to the central axis Y, and in some examples, such common plane may be parallel to the common plane of the upper truss members 860.

[0097] In various embodiments, the lower truss bars 874 can be cylindrical bars, while in further embodiments, such lower truss bars 874 or lower truss members 870 can be any suitable shape, such as an I-beam, a box truss, etc. Additionally, in various embodiments, the number of lower truss bars 874 or lower truss members 870 associated with each outer column 850 can be any suitable number, such as 1, 2, 3, 4, 5, 10, 25, 100, etc.

[0098] As shown in the example embodiment 100D of the floating wind turbine 100 in Figures 8-11, the cross beams 880 can extend between each outer column 850 and the central column 840 from a lower end of each outer column 850 to a respective position at an upper end of the central column 840. However, in further embodiments, the cross beams 880 can extend between each outer column 850 and the central column 840 from an upper end of each outer column 850 to a respective position at a lower end of the central column 840.

[0099] For example, as shown in FIG. 9, a first outer column 850A may be connected to the central column 840 via a first cross beam 880A, a second outer column 850B may be connected to the central column 840 via a second cross beam 880B, a third outer column 850C may be connected to the central column 840 via a third cross beam 880C, and a fourth outer column 850D may be connected to the central column 840 via a fourth cross beam 880D.

[0100] Further, the four cross beams 880A, 880B, 880C, 880D may be equally spaced around the central post 840, with each adjacent cross beam 880 being 90° apart from one another about the central axis Y. For example, the first and third cross beams 880A, 880C may be disposed in a first common plane that coincides with the central axis Y. The second and fourth cross beams 880B, 880D may be disposed in a second common plane that coincides with the central axis Y and is perpendicular to the first common plane of the first and third cross beams 880A, 880C.

[0101] In various embodiments, the cross beams 880 can be cylindrical bars, however, in further embodiments, such cross beams 880 can be any suitable shape, such as an I-beam, a box truss, etc. Additionally, in various embodiments, the number of cross beams 880 associated with each outer column 850 can be any suitable number, such as 1, 2, 3, 4, 5, 10, 25, 100, etc.

[0102] In various embodiments, the floating wind turbine 100 may be operable to change configurations between an upright configuration, as shown in Figures 8 and 9, and a folded configuration, as shown in Figure 10. For example, the outer columns 850 may be individually movably coupled to the central column 840 such that the outer columns 850 can be folded upwards and / or downwards relative to the tower body 110, thereby retracting the outer columns 850 closer to the central axis Y and reducing the maximum dimension of the hull assembly 830, which may be desirable for transportation of the floating wind turbine 100 in some examples described herein.

[0103] 10, a first pair of adjacent outer columns 850B, 850C can be configured to fold downward relative to the tower body 110 such that the outer columns 850 are retracted toward the central axis Y such that the pair of outer columns 850B, 850C is disposed fully or at least partially below the bottom of the central column 840. A second pair of adjacent outer columns 850A, 850D can be configured to fold upward relative to the tower body 110 such that the outer columns 850 are retracted toward the central axis Y such that the pair of outer columns 850A, 850D is disposed fully or at least partially above the top of the central column 840 around the tower shaft 112 of the tower body 110.

[0104] 10, in various embodiments, the major axis of each of the outer posts 850 can remain parallel to the central axis Y in the folded configuration of FIG. 10 and / or during the process of the outer posts 850 folding upward or downward from an upright configuration to a folded configuration. In some embodiments, such folding can be based on one or more rotatable connections between the outer posts 850 and the central post 840, and / or one or more translation-rotation connections between the outer posts 850 and the central post 840.

[0105] For example, the respective ends of the upper truss member 860 and the lower truss member 870 can be rotatably coupled to the respective outer column 850 and central column 840, thereby allowing the outer column 850 to rotatably fold up and / or down. Additionally, the end of the cross beam 880 rotatably coupled to the central column 840 can be configured to move up and down along the length of the central column 840 and / or the tower shaft 112 of the tower body 110, and the opposite end of the cross beam 880 coupled to the respective outer column 850 can be rotatably coupled to the respective outer column 850, such that the cross beam 880 folds towards the central column 840 and / or the tower shaft 112 when the outer column 850 is rotatably folded up and / or down.

[0106] For example, referring to Figures 9 and 10, a first pair of adjacent outer columns 850B, 850C can be configured to rotatably fold downward relative to the tower body 110, with the opposite ends of the cross beams 880B, 880C coupled to the central column 840 moving downward along the face of the central column 840 via the respective cross beam lower tracks 820, and based on the rotatable coupling of the ends of the second and third cross beams 880B, 880C, the cross beams 880B, 880C fold toward the central column 840 into the folded configuration of Figure 10. (The lower track 820B of the second cross beam 880B is shown in Figure 9.) Thus, the first pair of adjacent outer columns 850B, 850C folds closer to the central axis Y, and thus the pair of outer columns 850B, 850C is disposed completely or at least partially below the bottom of the central column 840.

[0107] The second pair of adjacent outer columns 850A, 850D may be configured to be rotatably folded relative to the tower body 110 such that the opposite ends of the cross beams 880A, 880D coupled to the central column 840 move upward along the plane of the tower shaft 112 of the tower body 110 via the respective cross beam upper tracks 810A, 810B, and based on the rotatable coupling of the ends of the first and fourth cross beams 880A, 880D, the cross beams 880A, 880D fold toward the tower body 110 into the folded configuration of FIG. 10. Thus, the second pair of adjacent outer columns 850A, 850D folds upward in a direction proximate to the central axis Y, such that the second pair of outer columns 850A, 850D is positioned completely or at least partially above the top of the central column 840 near and around the tower shaft 112 of the tower body 110.

[0108] Folding the outer columns 850 from an upright configuration to a folded configuration (and vice versa) can be performed in a variety of suitable ways. For example, in some embodiments, the translational coupling of the cross beams 880 in the cross beam upper and lower tracks 810, 820 can be based on buoyancy of the central column 840 and / or the outer columns 850 as described herein and / or can be motorized (e.g., fluid, electric, or fuel driven), which allows for up and down movement of the cross beams in the upper and lower tracks 810, 820, and the outer columns 850 can be motorized up and / or down. Thus, in various embodiments, configuring the floating wind turbine 100 between the upright / extended configuration and the folded configuration can be motorized based on passive and / or powered translational movement of the cross beams 880 in the cross beam upper and lower tracks 810, 820.

[0109] In further embodiments, the translational movement of the cross beam 880 can be performed mechanically by a user turning a crank or otherwise applying an external mechanical force. In further embodiments, other parts of the floating wind turbine 100, such as a cable, a winch, a motor on a rotatable coupling, etc., can be configured to actuate the outer masts 850. In some embodiments, actuation of the outer masts 850 can be performed by an external device, such as a crane. In some embodiments, actuation of the outer masts 850 can be performed based on gravity or buoyancy, such as based on ballast and / or air introduced to or removed from the central mast 840 and / or one or more of the outer masts 850.

[0110] In some embodiments, such as those shown in Figures 8-11, the outer columns 850 are configured only to fold up or down from an upright configuration to a folded configuration. For example, a given outer column 850 may be associated only with a cross beam upper track 810 or a cross beam lower track 820, such that a given outer column 850 is only operable to fold up or down from an upright configuration to a folded configuration. In the example of Figures 8-11, the floating wind turbine 100 has only two cross beam upper tracks 810 and two cross beam lower tracks 820, such that a first pair of outer columns 850B, 850C are configured to fold only downwards and a second pair of outer columns 850A, 850D are configured to fold only upwards.

[0111] However, in some embodiments, one or more of the outer columns 850 can be configured to fold in both directions, e.g., include both upper and lower cross beam tracks 810, 820. Also, in some embodiments, each of the outer columns 850 can be actuated individually or can always be configured to actuate as a group. For example, the first pair of outer columns 850B, 850C can be configured to actuate together as a group, the second pair of outer columns 850A, 850D can be configured to actuate together as a group, all four outer columns 850A, 850B, 850C, 850D can be configured to actuate together as a group, etc.

[0112] In various embodiments, the floating wind turbine 100 can be configured in parts for assembly and / or disassembly, which may be desirable for transportation as described herein. For example, the upper truss member 860, the lower truss member 870, and / or the cross beams 880 can have connections (e.g., by pins, bolts, etc.) that allow such elements to be easily connected and disconnected from the central column 840 and / or the outer columns 850, which may allow the upper truss member 860, the lower truss member 870, and / or the cross beams 880 to be separable from the central column 840 and / or the outer columns 850, and may allow the outer columns 850 and such elements to be separated from each other and from the central column 840. In some embodiments, the central column 840 can be separated from the tower 110. Additionally, in various embodiments, elements such as the nacelle 170, the blades 174, the rotor, etc. can be configured to be disassembled from each other and / or from the tower 100. For example, in various embodiments, one or more of such couplings may be a non-permanent coupling instead of a weld or other integral coupling.

[0113] A single floating wind turbine 100 or an array of multiple floating wind turbines 100 may be manufactured, erected, or positioned in a variety of suitable manners, with various portions being made on land and / or on the body of water 102. For example, in some embodiments, elements such as the tower 110, nacelle 170, blades 174, center column 840, outer columns 850, upper truss member 860, lower truss member 870, and / or cross beams 880 may be manufactured separately and transported disassembled, partially assembled, or fully assembled from a manufacturing site to a port, dock, or other location in the body of water 102.

[0114] For example, using FIGS. 8-11 as illustrations, in some embodiments, the hull assembly 830 may be fully assembled (which may or may not be coupled with the tower 110) and transported to the body of water 102 in a folded configuration (see, e.g., FIG. 10). In some examples, the center columns 840, outer columns 850, upper truss members 860, lower truss members 870, and / or cross beams 880 may be manufactured separately, transported to the body of water in a disassembled set, and assembled at the body of water 102. In various embodiments, it may be necessary for the tower 110 to be in the folded configuration so that the outer columns 850 can engage the tower 110 instead of collapsing too far or moving undesirably in the folded configuration.

[0115] In some embodiments, once the tower 110 is integrated into the hull assembly 830 on or near land, in various examples, the assembled floating wind turbine 100 may be towed from the port to a location on the body of water 102 where the floating wind turbine 100 is to be installed. Many ports have draft or air draft limitations, as previously mentioned, which may be the distance from the water surface 101 to the highest point of the vessel, the cargo on the vessel, or the cargo being towed by the vessel. Draft limitations may be 7m, 8m, 9m, 10m, 12m or less, etc. Air draft limitations may be 35m, 40m, 45m, 50m, 55m, 60m, 70m, 75m, 80m, 85m, 90m or less, etc. Once these obstacles or limitations are cleared, the floating wind turbine 100 may be reconfigured to have a larger draft, or a larger air draft, or both a larger draft and a larger air draft. For example, the floating wind turbine 100 may be configured from a folded configuration to an upright configuration, where the folded configuration complies with or is compatible with an obstacle or restriction (e.g., a draft restriction), but the upright configuration does not comply with or is not compatible with one or both of the obstacles and restrictions.

[0116] 8-11 as an example, in various embodiments, the process of erecting the floating wind turbine 100 may include submerging one or more of the front floats (e.g., the first and fourth outer columns 850A, 850D) in the water body 102 to reach an extended configuration (e.g., as shown in FIG. 11 ) by filling one or more of the front floats (e.g., the first and fourth outer columns 850A, 850D) and / or the central column 840 with ballast (e.g., water from the water body 102 in which the floating wind turbine 100 is located). In doing so, the cross beams 880 may move along their respective upper tracks 810 and be fixed (e.g., temporarily) in place.

[0117] In various embodiments, when the floating wind turbine 100 is submerged in the body of water 102 below the water line (e.g., based on filling one or more columns 840, 850 with ballast), one or more rear floats (e.g., the second and third columns 850B, 850C) may transition from a folded configuration (e.g., as shown in FIG. 10) to an extended configuration (e.g., as shown in FIG. 11). For example, when the floating wind turbine 100 is submerged to a sufficient height in the body of water 102, the buoyancy of one or more rear tanks (e.g., the second and third columns 850B, 850C) may cause the cross beams 880 of such rear tanks to pass through the lower track 820 and reach an extended position, as shown in FIG. 11.

[0118] The cross beam 880 can be fixed (e.g., temporarily) in place, and the floating wind turbine 100 can be erected into an upright configuration in various embodiments by (e.g., partially) evacuating the front float(s) (e.g., the first and fourth columns 850A, 850D) and / or the center column 840, and partially filling the rear float(s) (e.g., the second and third columns 850B, 850C). A large uprighting moment can be generated by the change in ballast, causing the floating wind turbine 100 and turbine 700 to upright from the configuration shown in FIG. 11 and reach an operable upright configuration as shown in FIG. 8. In some embodiments, the cross beam 880 can be fixed in place by inserting a pin into the cross beam 880 to prevent it from moving. In some examples, such pin insertion can be triggered remotely, such as by an operator of the support vessel.

[0119] In some embodiments, the outer columns 850 can be extended one by one. Moreover, in some embodiments, the floating wind turbine 100 can be rotated (e.g., about the main axis Y) based on ballast being inserted into and / or removed from the columns 850, which may be desirable in facilitating sequential extension of the outer columns 850 one by one. For example, a first folded, downward facing outer column 850 can be extended based on ballast being added to the first folded outer column 850, causing it to sink and extend. Changing the buoyancy of one or more outer columns 850 can cause the floating wind turbine 100 to rotate, causing a second folded outer column 850 to face downward, causing the second folded outer column 850 to sink downward and extend. Further folded columns 850 can be sequentially extended in a similar manner.

[0120] In some embodiments, in such an operable upright configuration, the lower truss member 870 can be fully submerged in the body of water 102 below the surface 101 of the water 102, the central and outer columns 840, 850 can be partially submerged in the water 102 with a lower portion submerged in the water 102 below the water surface 101 and an upper portion out of the water 102 above the water surface 101, the upper truss member 860 can be located above the water surface 101 of the water 102, and the tower 110 can be located above the water surface 101 of the water 102. In various embodiments, the height of the central column 840 and the outer columns 850 above or below the surface 101 of the water 102 can be varied based on the amount of ballast and / or air in the ballast tanks of the central column 840 and the outer columns 850.

[0121] In some embodiments, transitioning some or all of the outer columns 850 from a folded configuration (e.g., FIG. 10 ) to an extended configuration (e.g., FIG. 11 ) may be performed entirely based on buoyancy and / or gravity. For example, motorized or other actively powered actuation of the upper truss member 860, the lower truss member 870, and / or the cross beams 880 may be unnecessary. In other words, in some embodiments, changing the configuration of the floating wind turbine 100 between the folded and extended configurations may be performed substantially or entirely based on ballast or air being introduced or removed from the central column 840 and / or the outer columns 850.

[0122] In one embodiment, a ballast pump is located on the floating wind turbine 100 and can be remotely operated to perform the filling of the ballast tanks (e.g., center column 840 and / or outer columns 850). In another embodiment, the ballast tanks (e.g., ballast tanks of center column 840 and / or outer columns 850) are filled by opening valves on the columns via a remotely operated vehicle (ROV) or diver. In another embodiment, the ballast tanks are connected via hoses to ballast pumps on board a support vessel such as a boat, ship, etc. In such an embodiment, the filling and emptying of such ballast tanks can be performed by operating the same pump in reverse.

[0123] In various examples, after the floating wind turbine 100 is erected and connected to the electrical cable system 155 and / or the mooring system 150, the turbine 700 may be commissioned for installation on the floating wind turbine 100. However, in some embodiments, the turbine 700 may be installed on land or during transportation over water to an installation site and may be present when the floating wind turbine 100 is erected. For example, in some embodiments, the erection operation may be performed with the nacelle 170 and blades 174 pre-installed, or the erection operation may be performed without the nacelle 170 and blades 174 pre-installed, with such elements being added after the erection operation. Some embodiments may include a nacelle 170 and blades 174 that can be pre-assembled in a horizontal orientation.

[0124] As previously mentioned, such installation or erection methods can be reversed in part or in whole when the floating wind turbine 100 returns to port for maintenance, decommissioning, etc. This can reduce the draft of the floating wind turbine 100, allowing it to enter ports with draft restrictions or access shallow waters. Additionally, the tower 110 can, in various instances, be moved to a sideways orientation without the need for large tugboats if the vertical center of gravity is aligned with or close to the tower axis X. In some embodiments, the floating wind turbine 100 can be loaded onto a barge (e.g., a submersible barge) for transport to or from shore.

[0125] Thus, a method of installing at least one floating wind turbine 100 may include one or more of the following steps, which may begin with assembling the tower 110 and a portion of the hull assembly 830, and then coupling the tower 110 to the hull assembly 830. Some or all of such assembly may occur on land, including at a port or shoreline, or on land away from the port or shoreline. For example, the tower 110 and the hull assembly 830 (or portions thereof) may be transported as separate pieces to a port or shoreline, and the tower 110 and the hull assembly 830 (or portions thereof) may be assembled to form a complete or substantially complete floating wind turbine 100. In an example embodiment, each of the tower 110 and the hull assembly 830 may be assembled in parallel. For example, the outer columns 850 may be attached to the lower truss members 860 and upper truss members 870, and the cross beams 880 during the assembly of the tower 110.

[0126] In one embodiment, the lower section of the tower 110 is coupled to the tower base. The central tower 110 can be raised off the ground using temporary supports to allow the forward floats (e.g., the first and fourth outer columns 850A, 850D) to be connected to the lower part. For example, the two forward floats can be connected (e.g., via pin bearings) to the central column 840. The two aft floats (e.g., the second and third outer columns 850B, 850C) can be connected (e.g., via pin bearings) to the central column 840. The remaining sections of the tower, such as the nacelle, rotor, etc., can be attached to the tower shaft 112.

[0127] Such a complete or substantially completed floating wind turbine 100 may have the tower 110 in a horizontal or near horizontal configuration during assembly and / or during a portion of the journey from the port or shoreline to the desired location where the floating wind turbine 100 will be installed. In one embodiment, the turbine may be coupled to the tower base in a sideways position. In such an embodiment, a smaller, more readily available crane (e.g., a gantry crane) may be used to lift the tower sections, nacelle, and blades. Solid ballast may be added to the center or outer columns 840, 850 before, during, or immediately after turbine installation to lower the center of gravity of the structure. In one embodiment, the solid ballast may take the form of batteries.

[0128] In another embodiment, the platform can tow the turbine in a sideways position so that the turbine drag can be reduced. In one such embodiment, the erection of the turbine can occur at the wind farm site. For example, where possible or desirable, the floating wind turbine 100 can be converted from a configuration in which the tower 110 is in a horizontal or near-horizontal configuration to an upright configuration in which the tower 110 is in a vertical or near-vertical configuration so that the floating wind turbine 100 can be connected to a mooring and cabling system.

[0129] In some embodiments, once the turbine is integrated into the tower 110, the floating wind turbine 100 can be towed from the port in various examples. As previously mentioned, many ports have water or air draft limitations. In one embodiment, the fully assembled floating wind turbine 100 can be transported by barge. In another embodiment, the fully assembled floating wind turbine 100 can be slid directly into the water (e.g., in a folded configuration as shown in FIG. 10) and towed by a tow line 410. In another embodiment, the floating wind turbine 100 can be assembled in a dry dock, and the dry dock can be filled with water after the assembly process is completed. The assembled floating wind turbine 100 can then be towed from the port to an offshore location (e.g., a wind farm site). This can be done by a standard tugboat in some examples. The floating wind turbine 100 can be transported by a vehicle, such as a self-propelled modular transporter, commonly used in port facilities in some examples. In this manner, the fully assembled floating wind turbine 100 can be loaded onto a barge for transportation offshore.

[0130] In various embodiments, once the port is clear of any obstructions, restrictions, or shallow waters, the floating wind turbine 100 can be erected. For example, the floating wind turbine 100 can be towed from the port via the tow line 410 in a folded configuration with no or substantially no ballast (e.g., water) on the center or outer columns 840, 850, as shown in FIG.

[0131] The floating wind turbine 100 is erected from the folded configuration (e.g., as shown in FIG. 10 ) by filling one or more columns 850 of the first set (e.g., the first outer column and the fourth outer column 850A, 850D) and / or the central column 840 with ballast (e.g., water) to change the buoyancy of the one or more columns 850 of the first set, such that the one or more columns 850 of the first set sink within the body of water 102 and reach the extended configuration (e.g., as shown in FIG. 11 ). In various embodiments, such a change in configuration may include translating the cross beams 880 of the one or more columns 850 of the first set along their respective upper tracks 810.

[0132] In various embodiments, as shown in the example of FIG. 11 , extending the first set of one or more posts 850 can include the first set of one or more posts 850 going from being partially submerged in the water 102 to being fully submerged in the water 102, and the central post 840 going from being partially submerged in the water 102 to being fully submerged in the water 102.

[0133] In various embodiments, the second set of one or more pillars 850 (e.g., second and third pillars 850B, 850C) can transition from a folded configuration (e.g., as shown in FIG. 10) to an extended configuration (e.g., as shown in FIG. 11). For example, as shown in FIG. 11, buoyancy of the one or more pillars 850 of the second set can cause the cross beams 880 of the one or more pillars 850 of the second set to translate along the lower track 820 to reach the extended position. In some embodiments, the one or more pillars 850 of the second set can remain floating on the surface 101 of the body of water 102 with a portion of the one or more pillars 850 of the second set disposed within the water 102 and a portion of the one or more pillars 850 of the second set remaining out of the water while the one or more pillars 850 of the second set transition from the folded configuration to the extended configuration.

[0134] In some embodiments, the extension of the first set of one or more pillars 850 and the extension of the second set of one or more pillars 850 may occur simultaneously or sequentially in any suitable order. In some embodiments, when the one or more pillars 850 of the first set and the central pillar 840 are submerged in the body of water 102, the one or more pillars 850 of the second set may remain floating on the surface 101 of the body of water 102 based on the buoyancy of the one or more pillars 850 of the second set, causing the extension of the one or more pillars 850 of the second set.

[0135] The floating wind turbine 100 can be erected to an upright configuration, in various embodiments, by removing ballast from the first set of one or more columns 850 and / or the central column 840. Additionally, in some examples, during such erection, a second set of one or more columns 850 can be at least partially filled with ballast. Such a change in ballast in the first set and / or second set of one or more columns 850 can generate an uprighting moment that can upright the floating wind turbine 100 from the configuration shown in FIG. 11 to reach an operational upright configuration as shown in FIG.

[0136] In some embodiments, the first and second sets of one or more pillars 850 may be filled with the same amount of ballast to create equal buoyancy for the first and second sets of one or more pillars 850, or the ballast for the first and second sets of one or more pillars 850 may be configured in other ways to create equal buoyancy for the first and second sets of one or more pillars 850 (e.g., filling pillars with different weights with different amounts of ballast).

[0137] Various example floating wind turbines 100 may include four outer columns 850A, 850B, 850C, 850D, although further embodiments may include any suitable number of columns 850 described herein, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16, 25, 100. For example, Figure 12 illustrates an example embodiment of a floating wind turbine 100 having three outer columns 850A, 850B, 850C.

[0138] In this example, three outer posts 850A, 850B, 850C are equally spaced around the central post 840, with each adjacent outer post 850 spaced 120° apart from one another about the central axis Y and defining three planes of symmetry that are coincident with the central axis Y. It will be apparent that the description of an embodiment having four outer posts 850 may, in accordance with certain examples, be similarly applicable to embodiments having other numbers of outer posts 850 (e.g., three).

[0139] Additionally, an embodiment 100D of a floating wind turbine 100 having three outer columns 850A, 850B, 850C (or other number of outer columns 850) as shown in FIG. 12 may be folded or otherwise configured in a folded, extended, and / or erected configuration as described in other example embodiments herein. Taking FIG. 12 as an example, one or two columns 850 of the three outer columns 850A, 850B, 850C may be configured to fold upward (e.g., the first and fourth columns 850A, 850D shown in FIG. 10), and one or two other columns 850 of the three outer columns 850A, 850B, 850C may be configured to fold downward (e.g., the second and third columns 850B, 850C shown in FIG. 10). Similarly, introduction and / or removal of ballast from each column 850 may extend and / or retract the front and rear sets of one or more columns 850 to erect or lower the floating wind turbine 100 as described herein. The outer columns 850 may be configured to move via tracks 810, 820 as described herein, or may lack such tracks 810, 820. In some embodiments where tracks 810, 820 are not present, the rigidity of the upper truss member 860 and / or lower truss member 870 may maintain alignment of the columns 850 during the deployment process. In some examples, the ends of the cross beam 880 may be attached to a winch line that guides the cross beam 880 to its final position in a controlled manner. Once the cross beam 880 reaches its final position, a pin may be inserted into the cross beam 880 to lock the cross beam 880 in place.

[0140] 12, the floating wind turbine 100 may include various access elements 890, which may include one or more ladders 892, one or more outer column platforms 894, one or more walkways 896, and one or more central column platforms 898. For example, when the floating wind turbine 100 is floating on the body of water 102, a boat or vessel may dock to the floating wind turbine 100 and a human operator may climb a ladder 892 on one of the outer columns 850 to reach the outer column platform 894 and cross the walkway 896 to reach the central column platform 898. In various examples, the tower 110 may house elements of the floating wind turbine 100 that are accessible to a human operator for maintenance, repair, etc. Additionally, in various examples, a ladder may be provided within the tower body 112 to allow an operator to climb up to the nacelle 170 for maintenance, repair, etc. of elements of the turbine 700.

[0141] Additionally, while various embodiments may include multiple outer columns 850 radiating from a central column 840, other embodiments may include columns 840, 850 in any suitable configuration without a central column 840 present. For example, the set of outer columns 850 may be arranged in a triangular, square, pentagonal, hexagonal, heptagonal, octagonal, etc. configuration without a central column. Additionally, while various embodiments illustrated herein include a tower 110 extending from a central column 840, further embodiments may have one or more towers 110 extending from one or more outer columns 850, including embodiments in which a central column 840 is present.

[0142] One embodiment includes, consists essentially of, or consists of a downwind and / or upwind floating wind turbine 100 with a turbine control system that can be used to optimize the tilt angle of the floating wind turbine 100, or a portion thereof. Another embodiment includes, consists essentially of, or consists of a downwind and / or upwind floating wind turbine 100 with a teeter hub and a turbine control system that can be used to optimize the teeter angle of the rotor and the tilt angle of the floating wind turbine 100, or a portion thereof.

[0143] In some such embodiments, the floating wind turbine 100 may be allowed to passively pitch into the wind direction, such that there is no active control system on the floating wind platform, however, in various examples, the rotor plane of the floating wind turbine 100 may remain horizontally aligned, such that the wind turbine 700 is able to generate maximum power.

[0144] 13a, 13b, 14a, 14b, and 15, various embodiments of a floating wind turbine 100 are shown including a tower 110 disposed on a hull assembly 830 and a wind turbine 700 disposed on top of a tower body 112 of the tower 110. The wind turbine 700 comprises a nacelle 170 having a hub 172 and a number of blades 174 extending from the hub 172. The tower 110 may have a central axis Y. The hub 172 and the blades 174 may rotate about a rotor axis R, with the blades 174 having a blade plane B perpendicular to the rotor axis R.

[0145] In various embodiments, the hub 172 and corresponding rotor axis R can have a rotor tilt angle defined by the difference between the rotor axis R and the horizontal axis H (i.e., the axis perpendicular to gravity) when the central axis Y of the tower 110 is perfectly vertical (i.e., the central axis Y is parallel to the gravity axis). For example, FIG. 13a shows an example where the central axis Y of the tower 110 is at a heel angle of 0° (i.e., the central axis Y is parallel to the gravity axis) and the horizontal axis H is perpendicular to the central axis Y of the tower 110. In this example, the rotor axis R is 5° away from the horizontal axis H, and the rotor tilt angle for the example of FIG. 13a is defined as 5°. In some embodiments, the rotor tilt angle can be defined based on the difference in angle between the central axis Y and the blade plane B.

[0146] 13b, the floating wind turbine 100 of FIG. 13a is shown with a heel angle of 10° (i.e., the central axis Y of the tower 110 is 10° from true vertical as shown in FIG. 13a). Now, adding a heel angle of 10° and a rotor tilt angle of 5° means that the rotor axis R is 15° away from the horizontal axis H in this example. In various embodiments, having the rotor axis R parallel to the horizontal axis H (e.g., a misalignment of 0°) may be considered to be an optimal configuration for the wind turbine 700 (e.g., because such a configuration maximizes the swept area by the blades 174). Thus, in such embodiments, having the rotor axis R 15° away from the horizontal axis H may be considered to be a 15° deviation from the optimal configuration.

[0147] However, in further embodiments, any suitable axis may be defined as the optimal axis for the rotor axis R based on wind direction, wind angle, etc. In some examples, such optimal axis for the rotor axis R may change based on changing environmental conditions (e.g., wind direction, wind angle, etc.) or may remain the same as environmental conditions change.

[0148] In various embodiments, such misalignment of the rotor axis R may be desirable or acceptable for various reasons, but may come at the expense of reduced energy production, such as reduced annual electrical production (AEP). In some embodiments, the reduction in AEP may be considered acceptable or unacceptable. For example, in some embodiments, a reduction in AEP of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or less may be considered acceptable. In some embodiments, a reduction in AEP of 1%, 1.5%, 2%, 2.5%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 4%, 4.5%, 5% or more may be considered unacceptable. Thus, various embodiments of the floating wind turbine 100 may be configured to operate at a mean heel angle with a rotor tilt angle that produces rotor misalignment that causes reduced power generation (e.g., reduced AEP) compared to an optimal value that may or may not be considered acceptable.

[0149] Some various embodiments of the floating wind turbine 100 include a downwind turbine 700 with a rotor oriented 4°-8° upward from the horizontal H to increase the clearance between the tips of the blades and the tower shaft 112 during operation. Various examples of the floating wind turbine 100 generate thrust to generate power from the wind. The thrust may create an overturning moment on the floating wind turbine 100, which may result in an average heel angle on the floating wind turbine 100. In some examples, the average heel angle may be the average pitch angle of the floating wind turbine 100 in the direction of the wind. In some embodiments, the average heel angle may be 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, etc., or a range between such example values.

[0150] In some examples of floating wind turbines 100, the target design heel angle is the heel angle of the platform when the platform is subjected to the rated thrust of the turbine. The rated thrust may be the maximum average thrust on the turbine during operation. The design heel angle of the platform may depend on the hydrostatic stiffness of the platform. The hydrostatic stiffness may be a function of the center of gravity and buoyancy of the platform, the water surface moment of inertia area, and the restoring forces due to the mooring system. In some examples, increasing the hydrostatic stiffness of the floating wind turbine 100 may increase the cost and / or complexity of the system. For example, in some semi-submersible floating wind turbines 100, the hydrostatic stiffness may be increased by increasing the spacing of the pillars 840, 850, increasing the size of the pillars 840, 850, or both.

[0151] Floating wind turbines 100 in embodiments without an active control system may have a design heel angle of 4-5 degrees, resulting in a maximum rotor misalignment of 8-13 degrees from the horizontal axis H. Some floating wind turbines 100 with an active platform control system may have a design heel angle of 5-8 degrees, resulting in the tower 110 remaining vertical and the maximum rotor misalignment being maintained at 4-8 degrees. Some wind turbines may have a larger active control system, which may result in a larger heel angle, resulting in a rotor misalignment of 0 degrees. In some embodiments, the floating wind turbine may be configured to operate with rotor misalignment of -20°, -19°, -18°, -17°, -16°, -15°, -14°, -13°, -12°, -11°, -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, etc., or a range between such example values.

[0152] In various embodiments, an advantage of the floating wind turbine 100 operating at an inclination angle is that the wake generated by the floating wind turbine 100 can be driven into the body of water 102, reducing the impact on downstream floating wind turbines 100 where multiple floating wind turbines 100 are arranged in an array, group, or farm. In various embodiments, this may allow more floating wind turbines 100 to be grouped in a given area, which may be desirable for operators of the floating wind turbines 100.

[0153] In various embodiments, the design heel angle of the floating wind turbine 100 can be increased to 10-15 degrees, which may in some instances allow for a much smaller floating wind turbine 100 and / or a simpler mooring system, etc. In some embodiments, if the rotor tilt angle is 5 degrees above the horizontal axis H, the floating wind turbine 100 may tilt under the rated thrust of the floating wind turbine 100. If the turbine has a design heel angle of 10 degrees, in various embodiments, the rotor may be misaligned by only 5 degrees below horizontal, which may be the same as a conventional wind turbine with a 0 degree tilt angle (e.g., a tilt angle oriented vertically).

[0154] Various examples may include a rotor tilt angle of 5°, although further embodiments may define various other rotor tilt angles, including ranges between such example values, such as -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, etc. In some embodiments, the rotor tilt angle may be defined by various parts of the wind turbine 700, such as the physical location of the nacelle 170, the hub 172, etc. In some embodiments, the rotor tilt angle may be fixed based on the physical configuration of the wind turbine 700, or in some embodiments may be variable (e.g., motor-driven tilt of the nacelle 170 to change the rotor tilt angle).

[0155] In various embodiments, the floating wind turbine 100 may be configured or positioned to have a heel angle or operating angle (e.g., angle of central axis Y relative to true vertical) based on the weight or balance of the hull assembly 830 (e.g., based on the amount of ballast in columns 840, 850), the weight of various portions of the hull assembly 830, tower 110, and / or wind turbine 700, predicted or actual wind speed and / or direction, etc. For example, in various embodiments, wind forces on the floating wind turbine 100 may cause the floating wind turbine to tilt. Additionally, in various examples, wind, wave, or tidal action in the body of water 102 may cause the floating wind turbine 100 to sway or otherwise move within the body of water 102. Thus, the floating wind turbine 100 may be configured to operate within a range of heel angles. For example, in some embodiments, the floating wind turbine 100 can be configured to subtend an angle of -20°, -19°, -18°, -17°, -16°, -15°, -14°, -13°, -12°, -11°, -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, etc., or a range between such example values.

[0156] Additionally, the floating wind turbine 100 can be configured for upwind and / or downwind operation. An example of upwind operation is shown in Figures 13a and 13b, where the wind direction is towards the front of the hub 172 and blades 174, which then moves over the nacelle 170. In contrast, Figures 14a, 14b, and 15 show an example of downwind operation, where the wind direction is towards the rear of the hub 172 and blades 174, and the wind moves towards the rear of the nacelle 170.

[0157] For example, Figures 14a and 14b show an example where the rotor plane R is 5° away from normal to the shaft axis Y, resulting in a rotor tilt angle of 5°. As shown in Figure 14b, if the floating wind turbine is angled at 10° (e.g., based on wind, balance, etc.), the rotor axis R may be angled at -5° from the horizontal axis H. In another embodiment, the design heel angle may be 20°, resulting in a 10° misalignment between the rotor plane R and the shaft axis Y.

[0158] In some examples, the downwind teetered floating wind turbine 100 of various embodiments allows platform designers to achieve a larger design heel angle while maintaining zero degrees rotor misalignment. In some examples of the teetered floating wind turbine 100, the rotor axis R may be offset from a perpendicular angle to the main shaft axis Y. For example, FIG. 15 illustrates such an example. As shown in this example, the platform may have a 15° design heel angle, but the added effect of the downwind turbine and the teetered hub 1500 allowing the hub to move relative to the rotor axis R results in zero degrees rotor misalignment relative to the incoming wind. Thus, in various examples, the cost and complexity of the platform and mooring system may be further reduced than with a fixed-hub downwind wind turbine.

[0159] In various embodiments, the floating wind turbine 100 can include a variety of suitable control systems, such as a blade pitch controller, a nacelle yaw control, a generator torque control, etc. In various embodiments, the floating wind turbine 100 can include a computing system including a processor and a memory storing instructions that, when executed by the processor, perform various methods. In various embodiments, such a computing system can obtain data from a variety of suitable sensors, such as one or more accelerometers, temperature sensors, water sensors, humidity sensors, magnetic field sensors, gyroscopes, pressure sensors, torque sensors, light sensors, rain gauges, wind speed sensors, current sensors, depth sensors, GPS units, etc. For example, sensor data from such sensors can be used to determine the position, tilt angle, orientation, speed, power generation, turbine speed, depth within a body of water, and other conditions or configurations of the floating wind turbine 100. Additionally, in some examples, sensor data from such sensors can be used to determine environmental conditions, such as air temperature, water temperature, water salinity, wind speed, wind direction, wave height, wave direction, and precipitation. Various examples include systems and methods for controlling the blade pitch of the blades 174 to optimize power production from the floating wind turbine 100.

[0160] Because the floating wind turbine 100 is subject to dynamic wave loads, in various embodiments, the floating wind turbine 100 may undergo dynamic pitch motion. The magnitude of the pitch motion of the floating wind turbine 100 may be related to the magnitude of fluctuations in these environmental forces, as well as the pitch stiffness, damping, and other properties of the floating wind turbine 100. In some embodiments, the floating wind turbine 100 may exhibit dynamic pitch motions with amplitudes up to 5°. For example, for a floating wind turbine 100 with a design mean heel angle of 15°, the platform may tilt 10-20° from vertical. As the floating wind turbine 100 tilts forward and backward, the relative wind speed on the blades 174 may change. If the blade pitch is not adjusted, the operation of the floating wind turbine 100 may become unstable in some instances.

[0161] In some instances, the power absorbed by the generator may be proportional to the cube of the relative speed on the rotor. Approximating the sinusoidal motion of the platform as a step curve, increasing or decreasing the relative speed by a constant value ∇V, can, in various embodiments, increase the power generated in one cycle. Mathematically, the power generated by a stationary turbine is given by: ∞ : It can be proportional to the cube of . P ∞ ∝V 3 ∞

[0162] Mathematically, the power generated by a wind turbine rocking back and forth is determined by the relative wind speed V rel It can be proportional to the cube of .

[0163] P enh ∝V 3 rel =0.5*(V ∞ ,-∇V) 3 +0.5*(V ∞ ,+∇V) 3 =P ∞ +3V ∞ ∇V 2

[0164] The boosted power can be calculated as the square of the platform pitch speed multiplied by the hub height, ∇V 2 In some instances, the instantaneous power boost is small. However, over the life of the floating wind turbine 100, the boosted power can increase significantly.

[0165] To achieve this power augmentation in various embodiments, the thrust absorbed by the floating wind turbine 100 must remain relatively constant over one pitching cycle of the floating wind turbine 100. The natural period of pitch of the floating wind turbine 100 may be typically 20-30 seconds in some examples.

[0166] One embodiment of a wind turbine control system method 1600 is shown in Figure 16. The purpose of the controller may be to determine the speed of the rotor relative to the incident wind by measuring or determining the position, speed, acceleration, and incident wind speed and direction of the floating wind turbine 100. A blade pitch controller may then be operated to keep the rotor thrust relatively constant.

[0167] A side benefit of such a wind turbine control system in various embodiments is that the amplitude of thrust fluctuations can be minimized, resulting in reduced fatigue damage to the turbine 700, hull assembly 830, etc. Thrust fluctuations can create bending moments at the base of the tower 110, which can be transferred to the hull assembly 830. Reducing the thrust amplitude fluctuations reduces fatigue damage to the floating wind turbine 100 in various examples.

[0168] 16, at 1610, the position and / or orientation of the floating wind turbine 100 is measured or determined, which may include pitch, roll, and yaw movements, as well as speed, acceleration, etc. In various examples, such measurements or determinations may be based on sensor data obtained from sensors, as described herein. At 1620, incident wind speed, incident wind direction, etc. are measured or determined, which may be based on sensor data obtained from sensors, as described herein.

[0169] At 1630, the rotational motion along the wind direction, speed, and acceleration can in turn be determined, and at 1640, the rotational motion along the wind direction, speed, and acceleration over a time range (e.g., 20-30 seconds) can in turn be predicted or determined. At 1650, the blade pitch angle(s) can be determined to minimize thrust change and / or maximize power production over the controller's time range, and at 1660, the blade pitch system can be actuated to change the configuration of one or more blades 174 according to the determination at 1650.

[0170] Embodiments of the present disclosure can be described in light of the following provisions. 1. A tower including a turbine having a nacelle, a hub, and a number of blades extending from the hub, the tower having a central axis Y; 1. A hull assembly comprising: a central pillar coupled to the tower base at an upper portion thereof, the central pillar having a central pillar axis coinciding with the central axis Y; a plurality of outer columns, the plurality of outer columns including three or less outer columns, the plurality of outer columns including a first outer column, a second outer column, and a third outer column, the plurality of outer columns surrounding the central column and equally spaced about the central column, each adjacent outer column being spaced 120° apart from one another about the central axis Y, the plurality of outer columns may define three planes of symmetry coincident with the central axis Y; a plurality of upper truss members, the plurality of upper truss members including at least a first upper truss member, a second upper truss member, and a third upper truss member connecting the first outer column, the second outer column, and the third outer column, respectively, to the central column and extending from upper ends of the first outer column, the second outer column, and the third outer column, respectively; a plurality of lower truss members, the plurality of lower truss members including at least a first lower truss member, a second lower truss member, and a third lower truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively, and extending from lower ends of the first outer column, the second outer column, and the third outer column, respectively; a plurality of cross beams including at least a first cross beam, a second cross beam, and a third cross beam, the plurality of cross beams connecting the first outer column, the second outer column, and the third outer column, respectively, to the central column and extending diagonally between respective upper and lower truss members; the hull assembly is configured such that the first upper truss member, the second upper truss member, and the third upper truss member extend between the central pillar and each of the outer pillars in a first common plane, and the first lower truss member, the second lower truss member, and the third lower truss member extend between the central pillar and each of the outer pillars in a second common plane parallel to the first common plane and perpendicular to the central axis Y, and the three outer pillars are in an elongated configuration with their respective outer pillar central axes parallel to one another; the hull assembly is configured to assume a folded configuration from the extended configuration, with one or two of the three outer pillars configured to fold upward toward or near the tower and one or two other of the three outer pillars configured to fold downward toward or near a base of the central pillar; the hull assembly; A system comprising: 2. The system described in clause 1, wherein the central pillar and the three outer pillars are configured to be filled with water to act as ballast for the hull assembly. 3. The system of clause 1 or clause 2, wherein the system is configured to assume an upright configuration on a surface of a body of water and floating within the body of water, the hull assembly is in the extended configuration, the tower extends vertically above the surface of the body of water, the three outer columns and the central column are partially submerged within the body of water, and the system floats within the body of water based on buoyancy of the at least three outer columns and the central column. 4. A system as described in clause 3, wherein the system in the upright configuration violates a port draft tolerance of 8-12m and an air draft tolerance of 50-70m, but the system in the folded horizontal configuration does not violate either the port draft tolerance of 8-12m or the port air draft tolerance of 50-70m. 5. A hull assembly comprising: A central pillar having a central axis Y; a plurality of outer columns including a first outer column, a second outer column, and a third outer column, the plurality of outer columns surrounding the central column about the central axis Y and being equally spaced about the central column; a plurality of upper truss members including at least a first upper truss member, a second upper truss member, and a third upper truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively; a plurality of lower truss members including at least a first lower truss member, a second lower truss member, and a third lower truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively; a plurality of cross beams including at least a first cross beam, a second cross beam, and a third cross beam, the plurality of cross beams connecting the first outer pillar, the second outer pillar, and the third outer pillar, respectively, to the central pillar and extending diagonally therebetween. 6. The system of clause 5, further comprising a tower extending from said hull assembly containing a turbine. 7. The system of clause 5 or clause 6, wherein the hull assembly includes no more than three outer columns. 8. The system of any of clauses 5-7, wherein the hull assembly is configured to assume an extended configuration in which the first upper truss member, the second upper truss member, and the third upper truss member extend between the central pillar and each outer pillar in a first common plane, and the first lower truss member, the second lower truss member, and the third lower truss member extend between the central pillar and each outer pillar in a second common plane parallel to the first common plane and perpendicular to the central axis Y. 9. The system of any of clauses 5-8, wherein the hull assembly is configured to assume a folded configuration in which one or two of the plurality of outer pillars are configured to fold upwardly and one or two other of the plurality of outer pillars are configured to fold downwardly. 10. A hull assembly comprising: 1. A system comprising: the hull assembly including a plurality of outer pillars, including a first outer pillar, a second outer pillar, and a third outer pillar, the plurality of outer pillars circumscribing a central axis Y and being equally spaced about the central pillar. 11. A central pillar extending along the central axis Y; 11. The system of claim 10, further comprising a plurality of upper truss members, the plurality of upper truss members including at least a first upper truss member, a second upper truss member, and a third upper truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively. 12. A central pillar extending along the central axis Y; 12. The system of claim 10 or 11, further comprising: a plurality of lower truss members, the plurality of lower truss members including at least a first lower truss member, a second lower truss member, and a third lower truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively. 13. A central pillar extending along the central axis Y; 13. The system of any of clauses 10-12, further comprising a plurality of cross beams including at least a first cross beam, a second cross beam, and a third cross beam, each cross beam connecting the first outer column, the second outer column, and the third outer column to the central column and extending diagonally therebetween. 14. The system of any of clauses 10-13, further comprising a tower extending from the hull assembly. 15. The system of any of clauses 10-14, wherein the hull assembly includes no more than three outer columns. 16. The system of any of clauses 10-15, wherein the plurality of outer columns are configured to be filled with water to act as ballast for the hull assembly. 17. The system of any of clauses 10-16, wherein the hull assembly is configured to assume a folded configuration in which one or two of the plurality of outer pillars are configured to fold upwards and one or two other of the plurality of outer pillars are configured to fold downwards. 18. The system described in any of clauses 10-17, wherein the hull assembly is configured to assume an extended configuration in which a plurality of upper truss members extend between a central pillar and each of the outer pillars in a first common plane, and a plurality of lower truss members extend between the central pillar and each of the outer pillars in a second common plane parallel to the first common plane and perpendicular to the central axis Y. 19. The system described in clause 18, wherein the system is configured to assume an upright configuration on a surface of a body of water and floating within the body of water, the hull assembly is in the extended configuration, a tower coupled to the hull assembly extends vertically above the surface of the body of water, the plurality of outer columns are at least partially submerged within the body of water, and the system floats within the body of water based on the buoyancy of at least the plurality of outer columns. 20. A system as described in clause 19, wherein the system in the upright configuration violates the port draft tolerance of 50 to 70 m, but the system in the folded configuration does not violate the port draft tolerance of 50 to 70 m. 21. A method of operating a downwind floating wind turbine, comprising: A downwind type floating wind turbine floating on a body of water passively takes an average heel angle of 8° to 10° defined by an average pitch angle in a wind direction of a central axis Y of the tower of the downwind type floating wind turbine, the downwind type floating wind turbine passively taking the average heel angle from a force generated by the wind; the downwind type floating wind turbine operates with a maximum rotor misalignment in the range of -1° to -7° from a horizontal axis perpendicular to gravity, assuming that the mean heel angle is equal to 8° and 10° or is in the range of 8° to 10°; The downwind type floating wind turbine comprises: the tower including a turbine with a nacelle, a hub, and a number of blades extending from the hub, the blades configured to rotate about a rotor axis R, the blades having a blade plane B perpendicular to the rotor axis R, the rotor axis R having a static tilt angle defined by an angle of the rotor axis R relative to an axis perpendicular to the central axis Y, the downwind type floating wind turbine having a static tilt angle of 3° to 7°, such that the rotor axis R has a misalignment of 3° to 7° in a vertical position; 1. A hull assembly comprising: a central pillar coupled to the tower base at an upper portion thereof, the central pillar having a central pillar axis coinciding with the central axis Y; a plurality of at least three outer columns, including a first outer column, a second outer column, and a third outer column, the plurality of outer columns surrounding the central column about the central axis Y and being equally spaced about the central column; a plurality of upper truss members including at least a first upper truss member, a second upper truss member, and a third upper truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively; a plurality of lower truss members including at least a first lower truss member, a second lower truss member, and a third lower truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively; the hull assembly including a plurality of cross beams including at least a first cross beam, a second cross beam, and a third cross beam, the plurality of cross beams connecting the first outer pillar, the second outer pillar, and the third outer pillar, respectively, to the central pillar and extending diagonally therebetween; The method of claim 1, wherein the downwind type floating wind turbine is configured to assume an upright configuration on a surface of the body of water and passively float within the body of water without being coupled to a bottom of the body of water, the tower extends vertically above the surface of the body of water with the three outer columns and the central column partially submerged within the body of water, and the downwind type floating wind turbine floats within the body of water based on buoyancy of the at least three outer columns and the central column. 22. A method of operating a downwind floating wind turbine as described in clause 21, wherein the tilt angle of the rotor is configured to be changed. 23. A method of operating a downwind type floating wind turbine as described in clause 22, wherein the downwind type floating wind turbine is configured to operate as a teetered downwind type floating wind turbine and includes a teetered hub that enables the tilt angle of the rotor to be changed. 24. A method of operating a downwind floating wind turbine as described in any of clauses 21 to 23, wherein the central pillar and the three outer pillars are configured to be filled with water to act as ballast for the hull assembly. 25. A method of operating a downwind floating wind turbine comprising: A downwind type floating wind turbine floating on a body of water passively assumes an average heel angle of 8° to 10° defined by an average pitch angle in a wind direction of a central axis Y of the tower of the downwind type floating wind turbine; the downwind type floating wind turbine passively derives the mean heel angle from forces generated by the wind, and the downwind type floating wind turbine operates with a maximum rotor misalignment in the range of -1° to -7° from a horizontal axis perpendicular to gravity, assuming the mean heel angle is equal to 8° and 10° or is in the range of 8° to 10°; The method, wherein the tower includes a turbine having a nacelle, a hub, and a number of blades extending from the hub, the blades configured to rotate about a rotor axis R, the blades having a blade plane B perpendicular to the rotor axis R, the rotor axis R having a rotor tilt angle defined by an angle of the rotor axis R relative to an axis perpendicular to the central axis Y, and the downwind type floating wind turbine has a static tilt angle of 3° to 7°, such that the rotor axis R has a misalignment of 3° to 7° in a vertical position. 26. The downwind type floating wind turbine comprises: 1. A hull assembly comprising: a central pillar coupled to the tower base at an upper portion thereof, the central pillar having a central pillar axis coinciding with the central axis Y; a plurality of at least three outer columns, including a first outer column, a second outer column, and a third outer column, the plurality of outer columns surrounding the central column about the central axis Y and being equally spaced about the central column; a plurality of upper truss members including at least a first upper truss member, a second upper truss member, and a third upper truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively; a plurality of lower truss members including at least a first lower truss member, a second lower truss member, and a third lower truss member connecting the first outer column, the second outer column, and the third outer column to the central column, respectively; Clause 26. The method of operating a downwind type floating wind turbine as described in clause 25, further comprising: a plurality of cross beams including at least a first cross beam, a second cross beam, and a third cross beam, the plurality of cross beams connecting the first outer column, the second outer column, and the third outer column, respectively, to the central column and extending diagonally therebetween. 27. A method of operating a downwind type floating wind turbine as described in clause 25 or clause 26, wherein the downwind type floating wind turbine is configured to assume an upright configuration on the surface of the body of water and floating within the body of water without being coupled to a bottom of the body of water, the tower extends vertically above the surface of the body of water with a number of outer columns submerged in the body of water, and the downwind type floating wind turbine floats within the body of water based on the buoyancy of at least the number of outer columns. 28. A method of operating a downwind floating wind turbine comprising: Floating the downwind type floating wind turbine on a body of water with a mean heel angle within a range, the mean heel angle being defined by a mean pitch angle in a wind direction of a central axis Y of a tower of the downwind type floating wind turbine; operating the downwind type floating wind turbine with maximum rotor misalignment from a horizontal axis perpendicular to gravity while assuming the mean heel angle; The method, wherein the tower includes a turbine having a nacelle, a hub, and a plurality of blades extending from the hub, the plurality of blades being configured to rotate about a rotor axis R, the rotor axis R having a rotor tilt angle defined by an angle of the rotor axis R with respect to an axis perpendicular to the central axis Y. 29. A method of operating a downwind type floating wind turbine as described in clause 28, wherein the downwind type floating wind turbine passively assumes the mean heel angle from forces generated by the wind. 30. A method of operating a downwind type floating wind turbine according to clause 28 or clause 29, wherein the average heel angle is 5° and 15°, or between 5° and 15°. 31. A method of operating a downwind type floating wind turbine according to any of clauses 28 to 30, wherein the maximum rotor misalignment is between 1° and 13°. 32. A method of operating a downwind type floating wind turbine according to any of clauses 28 to 31, wherein the rotor tilt angle is between 1° and 10°, or between 1° and 10°. 33. A method of operating a downwind type floating wind turbine as described in any of clauses 28 to 32, wherein the downwind type floating wind turbine comprises a hull assembly including a plurality of at least three outer columns including a first outer column, a second outer column, and a third outer column. 34. A method of operating a downwind type floating wind turbine as described in any of clauses 28 to 33, wherein the downwind type floating wind turbine is configured to assume an upright configuration on the surface of the body of water and floating within the body of water without being coupled to a bottom of the body of water, the tower extends vertically above the surface of the body of water with a number of pillars submerged within the body of water, and the downwind type floating wind turbine floats within the body of water based on at least the buoyancy of the number of pillars. 35. A method of operating a downwind type floating wind turbine according to any of clauses 28 to 34, wherein the average heel angle is between 1° and 20°, or between 1° and 20°. 36. A method of operating a downwind type floating wind turbine according to any of clauses 28 to 35, wherein the maximum rotor misalignment is between 2° and 20°. 37. A method of operating a downwind floating wind turbine according to any one of clauses 28 to 36, wherein the inclination angle of the rotor is configured to be changed. 38. A method of operating a downwind type floating wind turbine as described in clause 37, wherein the downwind type floating wind turbine is configured to operate as a teetered floating wind turbine and includes a teetered hub that enables the tilt angle of the rotor to be changed. 39. A method of operating a downwind floating wind turbine comprising: A downwind type floating wind turbine floating on a body of water passively takes an average heel angle of 14° to 16° defined by an average pitch angle in a wind direction of a central axis Y of the tower of the downwind type floating wind turbine, the downwind type floating wind turbine passively taking the average heel angle from a force generated by the wind; the downwind type floating wind turbine operates with a maximum rotor misalignment in the range of -1° to 1° from a horizontal axis perpendicular to gravity, assuming that the mean heel angle is equal to 14° and 16° or is in the range of 14° to 16°; The method, wherein the tower includes a turbine having a nacelle, a hub, and a plurality of blades extending from the hub, the plurality of blades configured to rotate about a rotor axis R, the plurality of blades having a blade plane B perpendicular to the rotor axis R, the rotor axis R having a rotor tilt angle defined by an angle of the rotor axis R relative to an axis perpendicular to the central axis Y, the rotor tilt angle being between 3° and 7°, and the downwind type floating wind turbine having a static tilt angle of between 3° and 7° such that the rotor axis R has a misalignment of between 3° and 7° in a vertical position.

[0171] The described embodiments are susceptible to various modifications and alternative forms, specific examples of which are shown by way of example in the drawings and described in detail herein. It is to be understood, however, that the described embodiments are not limited to the particular forms or methods disclosed, but on the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives. Furthermore, elements of a particular embodiment should not be construed as being applicable only to that example embodiment, and thus elements of an example embodiment may be applicable to other embodiments. Furthermore, elements specifically shown in an example embodiment should be construed as covering embodiments that include, consist essentially of, or consist of such elements, or such elements may not be explicitly present in further embodiments. Thus, the description of an element present in an example should be construed as supporting some embodiments in which such elements are not explicitly present. Furthermore, the use of terms such as "float" should not be construed as indicating that a particular element or system is currently floating, but rather as indicating that such elements are configured, can be configured, or are capable of floating in a fluid.

Claims

1. A method of operating a downwind floating wind turbine, the method comprising: providing a downwind floating wind turbine, the downwind floating wind turbine including a tower, a turbine, and a hull assembly, the downwind floating wind turbine positioned to float within a body of water; the tower has a central axis Y and includes a turbine; The turbine includes a nacelle, a hub, and a plurality of blades extending from the hub; the plurality of blades are configured to rotate about a rotor axis R, the plurality of blades having a blade plane B perpendicular to the rotor axis R, and the plurality of blades are coupled to an actuator; a static tilt angle is defined by the angle of the rotor axis R relative to an axis perpendicular to the central axis Y, the static tilt angle being defined as being between 3° and 7°, and the rotor axis R having a misalignment with the central axis Y of between 3° and 7°; the hull assembly includes a central pillar, the central pillar being coupled to the tower base at an upper portion of the central pillar, the central pillar having a central pillar axis coinciding with the central axis Y; a blade pitch system using the actuator to adjust a blade pitch angle of one or more of the plurality of blades, thereby causing the downwind type floating platform to assume an average heel angle of 5° to 15°, defined by an average pitch angle in a wind direction of the central axis Y of the tower of the downwind type floating platform, wherein the downwind type floating platform assumes the average heel angle from a force generated by the wind; operating the downwind floating platform with a maximum rotor misalignment of +1° to −10° from a horizontal axis perpendicular to gravity while maintaining the average heel angle of 5° to 15°; A method comprising:

2. The hull assembly comprises: a central pillar, the central pillar being coupled to the tower base at an upper portion thereof, the central pillar having a central pillar axis coinciding with the central axis Y; a plurality of at least three outer pillars surrounding the central pillar and equally spaced about the central pillar and about the central axis Y; a plurality of at least three upper truss members, each of the plurality of at least three upper truss members connecting the plurality of at least three outer columns with the central column; a plurality of at least three lower truss members, each of the plurality of at least three lower truss members connecting the plurality of at least three outer columns with the central column; a plurality of at least three cross beams, each of which connects the plurality of three outer columns and the central column and extends diagonally between the plurality of three outer columns and the central column; The method of claim 1 , comprising:

3. further comprising configuring the hull assembly in an extended configuration floating within the body of water on the surface of the body of water without being attached to the bottom of the body of water; 3. The method of claim 2, wherein in the extended configuration, the tower extends vertically above the surface of the body of water with a plurality of at least three outer columns submerged in the body of water, and the downwind floating wind turbine floats in the body of water based on buoyancy of at least the plurality of at least three outer columns.

4. The method comprises: Providing a teetered hub and Using the teetered hub to change the static tilt angle; The method of claim 1 further comprising:

5. The method of claim 2, further comprising filling the central pillar and the plurality of at least three outer pillars with water, thereby ballasting the hull assembly.

6. The method of claim 2, further comprising adding ballast to the tower, thereby causing the hull assembly to be configured in the extended configuration.

7. The method of claim 1, further comprising configuring the hull assembly in a folded configuration; 7. The method of claim 6, wherein in the folded configuration, one or two of the plurality of at least three outer columns are configured to fold upward and one or two other columns of the plurality of at least three outer columns are configured to fold downward.

8. The method of claim 7, further comprising removing ballast from the tower, thereby causing the hull assembly to be configured into the folded configuration.

9. The method of claim 2, further comprising inserting a pin into one of the plurality of cross beams and the central column, thereby holding the cross beam in a predetermined position relative to the central column.

10. A floating wind turbine, comprising: a hull assembly; a tower extending from the hull assembly, the tower including a turbine; Equipped with The hull assembly includes: a central pillar with a central axis Y; a plurality of at least three outer pillars surrounding the central pillar and equally spaced about the central pillar and about the central axis Y; a plurality of at least three upper truss members, each of the plurality of at least three upper truss members connecting the plurality of at least three outer columns with the central column; a plurality of at least three lower truss members, each of the plurality of at least three lower truss members connecting the plurality of at least three outer columns with the central column; a plurality of at least three cross beams, each of the plurality of at least three cross beams connecting the plurality of at least three outer columns with the central column and extending diagonally between each of the upper and lower truss members; Including, the hull assembly is configured to assume an extended configuration, wherein the plurality of at least three upper truss members extend between the central pillar and each of the outer pillars in a first common plane, and the plurality of at least three lower truss members extend between the central pillar and each of the plurality of at least three outer pillars in a second common plane that is parallel to the first common plane and perpendicular to the central axis Y; 1. A floating wind turbine, wherein the hull assembly is configured to assume a folded configuration from the extended configuration, wherein in the folded configuration one or two of the plurality of at least three outer columns are configured to fold upward toward and near the tower, and one or two other columns of the plurality of at least three outer columns are configured to fold below a base of the central column and near the base of the central column.

11. A floating wind turbine as described in claim 10, wherein the central pillar and the plurality of at least three outer pillars are configured to be filled with water that acts as ballast for the hull assembly.

12. Further comprising a pin, 11. The floating wind turbine of claim 10, wherein in the extended configuration, the pin is inserted into one of the plurality of at least three cross beams and the central column, thereby holding that cross beam in position relative to the central column.

13. A floating wind turbine as described in claim 10, wherein adding ballast to the central pillar and the outer pillars causes the hull assembly to assume the extended configuration.

14. A floating wind turbine as described in claim 10, wherein the hull assembly includes three or fewer outer columns.

15. A floating wind turbine as described in claim 10, wherein removing ballast from the central pillar and the plurality of outer pillars causes the hull assembly to assume a folded configuration.

16. The hull assembly is configured to assume the folded configuration; 11. The floating wind turbine of claim 10, wherein in the folded configuration, one or two of the plurality of at least three outer columns are configured to fold upwards and one or two other columns of the plurality of at least three outer columns are configured to fold downwards.

17. A method of operating a floating wind turbine as claimed in any one of claims 10 to 16.

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