A horizontal wind turbine generator, comprising:
- a vertical cylindrical tower, a horizontal cylindrical nacelle, and a rotor;
- wherein the nacelle is rotably mounted on the tower, such that the nacelle can be rotated about a yaw axis, which axially extends vertically upward through the tower;
- wherein the rotor comprises a hub, from which extend two or more blades, and the hub is axially connected to a main shaft, which can rotate about a main shaft axis extending outward from the main shaft, such that the action of a wind on the blades causes a wind-induced rotation of the rotor about a rotor axis and of the main shaft about the main shaft axis;
- wherein the main shaft extends inwardly through the nacelle and transmissively connects through a gear box in the nacelle to a generator in the nacelle, such that the wind-induced rotation of the main shaft turns the generator and thereby generates electricity;
- wherein the rotation of the nacelle about the yaw axis is controlled by a yaw drive so as to change the orientation of the main shaft axis;
- wherein the hub comprises a main shaft ball, hub socket and outer hub, such that the main shaft ball is rigidly attached to the front end of the main shaft, and such that the blades extend outward from the outer hub, and such that blades have a pitch angle, which determines an angle of attack of the blades with respect to the wind direction;
- wherein the main shaft ball is spherical and the hub socket has an inner surface which is a spherical shell;
- and wherein the hub socket slidably surrounds the main shaft ball, such that the wind-induced rotational motion of the hub socket is transmitted to the main shaft ball by multiple cooperating rotational transfer means in the main shaft ball and in the hub socket;
- and wherein the rotational transfer means are coupled either mechanically or magnetically;
- wherein the rotational transfer means comprise multiple paired dynamic rotational couplers, one of which is a smaller coupler and one of which is a larger coupler;
- and wherein the dynamic rotational couplers comprise a first coupler and a second coupler;
- and wherein the first coupler is embedded in or affixed to the surface of the main shaft ball, and the second coupler is embedded in or affixed to the inner surface of the hub socket;
- and wherein either the first coupler or the second coupler can be the smaller coupler;
- wherein the second coupler is free to rotate with respect to the first coupler around a wind shear axis, which is perpendicular to a gradient in wind speed and is located along a line connecting positions of maximum forward rotation and maximum backward rotation of the blades;
- thereby enabling the smaller coupler to move freely within the perimeter of the larger coupler;
- and wherein the second coupler is not free to rotate with respect to the first coupler around the main shaft axis, such that rotation of the second coupler around the main shaft axis is transferred to the first coupler, thereby transferring rotation of the hub socket to the main shaft ball;
- wherein the dynamic rotational couplers permit the hub socket to rotate in relation to the main shaft ball about a wind shear axis;
- and wherein rotation of the hub socket with respect to the main shaft ball about the wind shear axis allows the blades of the rotor to move back-and-forth in response to wind shear forces, thereby maintaining a relatively constant tip speed ratio and angle of attack of the blades, so as to enable optimum conversion of wind energy to electrical energy;
- wherein a back-and-forth rotation of the blades around the wind shear axis is transferred to a back-and-forth rotation of the hub socket around the wind shear axis;
- and wherein the rotation of the hub socket around the wind shear axis can cause the hub socket to rotate around a hub axis, which is an axis perpendicular to the wind shear axis and to the main shaft axis, such that the rotation of the hub socket around the hub axis occurs when wind shear causes the blades to apply an unbalanced torque around the wind shear axis;
- wherein the rotation of the hub socket around the wind shear axis causes a change in the orientation of the rotor axis, such that the orientation of the rotor axis differs from the orientation of the main shaft axis, and such that the back-and-forth rotation of the dynamic rotational couplers enables the hub socket to rotate around the rotor axis, which has a different orientation than the main shaft axis;
- and
- wherein the rotation of the hub socket with respect to the main shaft ball about the wind shear axis and the hub axis allows the blades of the rotor to move back-and-forth about the wind shear axis and side-to-side about the hub axis in response to wind shear forces, thereby maintaining a relatively constant tip speed ratio and angle of attack of the blades, so as to enable optimum conversion of wind energy to electrical energy.