Floating wind turbine structure
A floating wind turbine structure comprising: a rotor carrying at least one blade, at least two support arms supporting a nacelle, said at least two support arms comprising upper and lower portions, said upper portions being associated with the nacelle and said lower portions being associated with means in the shape of floats, at least one support arm located upstream from the rotor relative to the wind direction, at least one support arm located downstream from the rotor relative to the wind direction, characterized in that the rotor is provided with a hollow shaft arranged to rotate about the nacelle.
1. A floating wind turbine structure comprising:
a nacelle;
a rotor bearing a blade, said rotor circumscribing said nacelle;
first and second support arms of the nacelle, the first and second support arms comprising upper and lower parts, the upper parts are associated with the nacelle and the lower parts are associated with means in the form of floats, the first support arm being located upstream of the rotor relative to a wind direction, the second support arm being located downstream of the rotor relative to the wind direction;
wherein the rotor is provided with a hollow spindle arranged to rotate around the nacelle.
2. A floating wind turbine structure as claimed in claim 1 , wherein the upper parts of the first and second support arms are rigidly connected together.
3. A floating wind turbine structure as claimed in claim 1 comprising a mooring point, wherein the mooring point is located upstream of a center of sail force relative to the wind direction.
4. A floating wind turbine structure as claimed in claim 1 , characterised in that the first and second support arms include a non-circular cross section so as to limit aerodynamic disturbances on the blade.
5. A floating wind turbine structure as claimed in claim 1 , wherein the hollow spindle of the rotor having a bore of revolution, wherein a ratio between a diameter of the bore and a maximum outer diameter defined by an end of the blade upon rotation of the rotor about the nacelle is between two and fifty percent.
6. A floating wind turbine structure as claimed in claim 1 arranged to be moored via a mooring point and further comprising:
a through-going recessed reel arranged to form a pivot with a vertical rotational axis so as to allow pivoting of the floating wind turbine structure relative to the mooring point, and
an umbilical wherein the umbilical passes into a recess of the through-going recessed reel.
7. A floating wind turbine structure as claimed in claim 1 wherein said rotor is connected to said nacelle by at least one roller bearing.
8. A floating wind turbine structure as claimed in claim 1 wherein said rotor is connected to said nacelle by a set of roller bearings.
9. A floating wind turbine structure as claimed in claim 1 wherein said rotor is connected to said nacelle such that said rotor moves relative to said nacelle.
10. A floating wind turbine structure as claimed in claim 1 wherein said nacelle is pivotable about an axis that is perpendicular to an axis of rotation of said rotor.
11. A floating wind turbine structure comprising:
a nacelle;
a rotor including a blade, said rotor circumscribing said nacelle and being connected to said nacelle such that said rotor rotates relative to said nacelle, said nacelle being pivotable about an axis that is perpendicular to an axis of rotation of said rotor;
at least first and second support arms rigidly connected to each other and said nacelle at first ends, the at least first and second support arms including a non-circular cross section.