# US 7,612,462 B2 · Floating wind turbine system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,462 B2 - Document ID: US7612462B2 - Status: Granted - Kind: B2 - Application number: 12/150,072 - Filed: 2008-04-24 - Published: 2009-04-09 - Granted: 2009-11-03 - Earliest claimed: 2007-10-08 - Inventors: Larry A. Viterna - Web page: https://patentgrep.com/patent/US7612462B2 ## CPC - B63B 35/44: Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices {(construction methods for floating offshore platforms B63B75/00)} - B63B 21/50: Anchoring arrangements {or methods} for special vessels, e.g. for floating drilling platforms or dredgers - F03D 13/10: Assembly of wind motors; Arrangements for erecting wind motors - F03D 13/40: Arrangements or methods specially adapted for transporting wind motor components - B63B 2021/505: {Methods for installation or mooring of floating offshore platforms on site} - B63B 2035/446: {for converting wind energy into electric energy} - F05B 2240/2213: and with the rotor downwind from the yaw pivot axis - F05B 2240/93: on a structure floating on a liquid surface - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02E 10/727: Offshore wind turbines - B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06) - F03D: WIND MOTORS - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site. ## Claims ### Claim 1 A floating wind turbine system comprising: a buoyant support tower, said support tower having a submersible end and a longitudinal axis; at least one buoyant stability arm extending from said support tower; a position retention device attached to said support tower, said position retention device operable to retain said support tower within a desired area while also allowing said support tower to move in response to at least one of changing wind conditions and changing wave conditions; and a wind turbine generator mounted upon said support tower, said wind turbine generator having a longitudinal axis that defines an acute angle with said support tower longitudinal axis. ### Claim 2 (depends on 1) The floating wind turbine system according to claim 1 wherein said stability arm has a longitudinal axis and further wherein said stability arm longitudinal axis defines an angle with said support tower longitudinal axis. ### Claim 3 (depends on 2) The floating wind turbine system according to claim 2 wherein said acute angle between said support tower longitudinal axis and said wind turbine generator longitudinal axis is a first acute angle and further wherein said angle defined by said support tower longitudinal axis and said stability arm longitudinal axis is a second acute angle that is within a range of 10 to 89 degrees. ### Claim 4 (depends on 3) The floating wind turbine system according to claim 3 wherein said second acute angle is less than said first acute angle. ### Claim 5 (depends on 3) The floating wind turbine system according to claim 3 wherein said position retention device includes a rotatable tether attachment mounted upon said submersible end of said support tower and a tether that extends from said tether attachment device to an anchor device, said tether attachment allowing rotation of said support tower relative to said tether while said tether and anchor device maintains the system in position. ### Claim 6 (depends on 5) The floating wind turbine system according to claim 5 wherein the system includes a submersible electrical conductor for transfer of electrical energy generated by the system to an electrical load. ### Claim 7 (depends on 4) The floating wind turbine system according to claim 4 wherein the system includes a plurality of stability arms extending from said support tower. ### Claim 8 (depends on 7) The floating wind turbine system according to claim 7 wherein the system includes two stability arms, said stability arms defining a stability arm angle therebetween that is within a range of 30 to 150 degrees. ### Claim 9 (depends on 8) The floating wind turbine system according to claim 8 wherein one of said stability arms has a first longitudinal axis that forms a first stability arm acute angle with said support tower longitudinal axis and further wherein said other of said stability arms has a second longitudinal axis that forms a second acute stability arm angle with said support tower longitudinal axis with said first stability arm acute angle being greater that said second stability arm acute angle to correct for torque effects upon said support tower generated by wind generator. ### Claim 10 (depends on 5) The floating wind turbine system according to claim 5 wherein said support tower includes at least one buoyancy chamber that is adapted to provide variable buoyancy for said support tower. ### Claim 11 (depends on 10) The floating wind turbine system according to claim 10 further including a pump and associated valves connected to said buoyancy chamber, said pump operative and co-operating with said valves to one of add water to, and subtract water from, said buoyancy chamber in said support tower to provide said variable buoyancy for said support tower. ### Claim 12 (depends on 11) The floating wind turbine system according to claim 11 wherein said at least one stability arm also includes at least one buoyancy chamber. ### Claim 13 (depends on 12) The floating wind turbine system according to claim 12 wherein said pump and associated valves are also connected to said buoyancy chamber in said stability arm, said pump also being operable and co-operating with said valves to one of add water to, and subtract water from, said buoyancy chamber in said stability arm to provide a variable amount of buoyancy for said stability arm. ### Claim 14 (depends on 11) The floating wind turbine system according to claim 11 wherein said wind turbine generator includes a rotor having at least one blade, a rotor hub and an electrical generator, said electrical generator being disposed within a nacelle that is mounted upon an end of said support tower that is opposite from said submersible support tower end. ### Claim 15 (depends on 14) The floating wind turbine system according to claim 14 wherein said wind turbine rotor includes a plurality of blades that define both an axis of rotation and a cone angle with a blade rotor plane that is perpendicular to said rotor axis of rotation and further wherein said blades are pivotabally mounted upon said rotor hub with said blades pivoting less than 20 degrees from said cone angle to reduce coupled motions of said blade rotor plane and motions of the support tower induced by wind and wave forces. ### Claim 16 (depends on 5) The floating wind turbine system according to claim 5 wherein said tether attachment includes a slip ring for transferring electrical power from generator to said submersible electrical conductor when the wind turbine system rotates relative to said tether. ### Claim 17 (depends on 5) The floating wind turbine system according to claim 5 wherein said support tower has a upper portion that extends above the surface of the water and further wherein said support tower upper portion has a cross sectional shape of an airfoil. ### Claim 18 (depends on 5) The floating wind turbine system according to claim 5 wherein said support tower includes a guy post attached substantially perpendicular to the said support tower longitudinal axis with at least one of first guy cables connected between said guy post and each end of said support tower, second guy cables connected between said guy post and the outside of said stability arms, third guy cables connected from said stability arms to said ends of said tower and fourth guy cables extend between the inner surfaces of the stability arms. ### Claim 19 (depends on 2) The floating wind turbine system according to claim 2 wherein said stability arm extends perpendicularly from said support tower.