Floating wind turbine systems and methods
A method of operating a downwind floating wind turbine comprising the downwind floating wind turbine floating in a body of water assuming mean heel angle within a range, the mean heel angle defined by a mean pitch angle of a central axis Y of a tower of the downwind floating wind turbine in a direction of wind; and the downwind floating wind turbine operating with a maximum rotor misalignment from a horizontal axis that is perpendicular to gravity while assuming the mean heel angle. The tower includes a turbine with a nacelle, hub and a plurality of blades extending from the hub, the plurality of blades configured to rotate about a rotor axis R, the rotor axis R having rotor tilt angle defined by an angle of rotor axis R relative to a perpendicular axis to the central axis Y.
1 . A method of operating a downwind floating platform, the method comprising:
providing the downwind floating platform, the downwind floating platform including a tower, a turbine, and a hull assembly, the downwind floating platform disposed to be floating in a body of water,
the tower having a central axis Y and including a turbine, the turbine including a nacelle, a hub and a plurality of blades, the 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 that is perpendicular to the rotor axis R, the plurality of the blades coupled with an actuator,
wherein a static tilt angle is defined by an angle of rotor axis R relative to a perpendicular axis to the central axis Y, the static tilt angle being between 3° and 7° and the rotor axis R has a misalignment of between 3° and 7° with respect to the central axis Y, and
the hull assembly including:
a central column coupled to a base of the tower at a top of the central column, the central column having a central column axis coincident 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 at least three outer columns surrounding and equally spaced about the central column about the central axis Y;
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 that respectively couple the first, second and third outer columns with the central column;
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 that respectively couple the first, second and third outer columns with the central column; and
a plurality of cross-beams, including at least a first-cross beam, a second cross-beam and a third cross-beam, that respectively couple and extend diagonally between the first, second and third outer columns and the central column;
adjusting, by a blade pitch system, using the actuator, one or more blade pitch angles of the plurality of blades, thereby causing the downwind floating platform to assume a mean heel angle of equal to or between 5° and 15° defined by a mean pitch angle of the central axis Y of the tower of the downwind floating platform in a direction of wind, the downwind floating platform assuming the mean heel angle from a force generated by the wind; and
operating the downwind floating platform with a maximum rotor misalignment between +1° and −10° from a horizontal axis that is perpendicular to gravity while assuming the mean heel angle of equal to or between 5° and 15°;
wherein the downwind floating wind platform is configured to passively float in the body of water without being coupled to a floor of the body of water, and
wherein the tower extends vertically above a surface of the body of water with the three outer columns and the central column partially submerged in the body of water, with the downwind floating platform floating in the body of water at least based on buoyancy of the three outer columns and the central column.
2 . The method of claim 1 , wherein the downwind floating platform is configured to operate as a teetering downwind floating platform and the hub is a teetered hub that allows a rotor tilt angle to be changed.
3 . The method of claim 1 , wherein the central column and the at least three outer columns are configured to be filled with water that acts as a ballast for the hull assembly.
4 . The method of claim 1 , further comprising:
measuring, by a first sensor, an orientation of the downwind floating platform, the orientation including position, velocity, and acceleration in pitch, roll, and yaw;
measuring, by a second sensor, incident wind speed and an incident wind direction; and
determining a prediction of rotational movement of the downwind floating platform based on the orientation, the incident wind speed, and the incident wind direction, the prediction of rotational movement including rotational motion, rotational velocity, and rotational acceleration; and
adjusting the one or more blade pitch angles based on the prediction of rotational movement.
5 . A method of operating a downwind floating platform, the method comprising:
providing the downwind floating platform, the downwind floating platform including a tower, a turbine, and a hull assembly, the downwind floating platform disposed to be floating in a body of water,
the tower having a central axis Y and including a turbine,
the turbine including a nacelle, a hub and a plurality of blades, the 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 that is perpendicular to the rotor axis R, the plurality of the blades coupled with an actuator,
wherein a static tilt angle is defined by an angle of rotor axis R relative to a perpendicular axis to the central axis Y, the static tilt angle is defined as being between 3° and 7° and the rotor axis R has a misalignment of between 3° and 7° with respect to the central axis Y;
adjusting, by a blade pitch system, using the actuator, one or more blade pitch angles of the plurality of blades, thereby causing the downwind floating platform to assume a mean heel angle of equal to or between 5° and 15° defined by a mean pitch angle of the central axis Y of the tower of the downwind floating platform in a direction of wind, the downwind floating platform assuming the mean heel angle from a force generated by the wind; and
operating the downwind floating platform with a maximum rotor misalignment between +1° and −10° from a horizontal axis that is perpendicular to gravity while assuming the mean heel angle of equal to or between 5° and 15°.
6 . The method of claim 5 , the method further comprising:
providing a downwind floating platform which comprises:
a hull assembly, the hull assembly including:
a central column coupled to a base of the tower at a top of the central column, the central column having a central column axis coincident 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 at least three outer columns surrounding and equally spaced about the central column about the central axis Y;
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 that respectively couple the first, second and third outer columns with the central column; and
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 that respectively couple the first, second and third outer columns with the central column.
7 . The method of claim 5 , wherein the downwind floating platform is configured to assume an upright configuration floating in the body of water, on a surface of the body of water without being coupled to a floor of the body of water, where in the upright configuration, the tower extends vertically above the surface of the body of water with a plurality of outer columns submerged in the body of water, with the downwind floating platform floating in the body of water at least based on buoyancy of the plurality of outer columns.
8 . A method of operating a downwind floating platform, the method comprising:
providing the downwind floating platform, the downwind floating platform including a tower, a turbine, and a hull assembly, the downwind floating platform disposed to be floating in a body of water,
the tower having a central axis Y and including a turbine,
the turbine including a nacelle, a hub and a plurality of blades, the plurality of blades extending from the hub,
the plurality of blades configured to rotate about a rotor axis R, the rotor axis R having rotor tilt angle defined by an angle of rotor axis R relative to a perpendicular axis to the central axis Y, the plurality of the blades coupled with an actuator;
adjusting, by a blade pitch system, using the actuator, one or more blade pitch angles of the plurality of blades, thereby causing the downwind floating platform to assume a mean heel angle within a range defined by a mean pitch angle of the central axis Y of the tower of the downwind floating platform in a direction of wind, wherein the downwind floating wind platform passively assumes the mean heel angle from a force generated by the wind; and
operating the downwind floating platform with a maximum rotor misalignment from a horizontal axis that is perpendicular to gravity while assuming the mean heel angle.
9 . The method of claim 8 , wherein the maximum rotor misalignment between 1° and 13°.
10 . The method of claim 8 , wherein the rotor tilt angle is equal to or between 1° and 10°.
11 . The method of claim 8 , wherein the downwind floating platform comprises a hull assembly that includes a plurality of at least three outer columns including a first outer column, a second outer column and a third outer column.
12 . The method of claim 8 , wherein the downwind floating platform is configured to assume an upright configuration floating on a surface of the body of water, without being coupled to a floor of the body of water, where the tower extends vertically above the surface of the body of water with a plurality of columns submerged in the body of water, with the downwind floating wind platform floating in the body of water at least based on buoyancy of the plurality of columns.
13 . The method of claim 8 , wherein the mean heel angle is equal to or between 1° and 20°.
14 . The method of claim 8 , wherein the maximum rotor misalignment is between 2° and 20°.
15 . The method of claim 8 , wherein the rotor tilt angle is configured to be changed.
16 . The method of claim 15 , wherein the downwind floating platform is configured to operate as a teetering floating wind turbine and the hub is a teetered hub that allows the rotor tilt angle to be changed.
17 . A method of operating a downwind floating platform, the method comprising:
providing the downwind floating platform, the downwind floating platform including a tower, a turbine, and a hull assembly, the downwind floating platform disposed to be floating in a body of water,
the tower having a central axis Y and including a turbine,
the turbine including a nacelle, a hub and a plurality of blades,
the 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 that is perpendicular to the rotor axis R, the plurality of the blades coupled with an actuator,
wherein a static tilt angle is defined by an angle of rotor axis R relative to a perpendicular axis to the central axis Y, wherein the static tilt angle is between 3° and 7°, and the rotor axis R has a misalignment of between 3° and 7° with respect to the central axis Y;
the hull assembly including a central column coupled to a base of the tower at a top of the central column, the central column having a central column axis coincident with the central axis Y;
adjusting, by a blade pitch system, using the actuator, one or more blade pitch angles of the plurality of blades, thereby causing the downwind floating platform to assume a mean heel angle within a range defined by a mean pitch angle of the central axis Y of the tower of the downwind floating wind platform in a direction of wind, wherein the downwind floating wind platform passively assumes the mean heel angle from a force generated by the wind; and
operating the downwind floating platform with a maximum rotor misalignment from a horizontal axis that is perpendicular to gravity while assuming the mean heel angle.