A wind turbine system is described comprising a plurality of wind turbine modules, each including a rotor, mounted to a support structure including a tower. In use, each rotor has an associated rotating unbalance that defines an unbalance vector. The wind turbine system includes control means configured to coordinate the rotational speeds of the plurality of rotors to attenuate oscillations of the support structure caused by the rotating unbalance of the rotors. Also described is a method of controlling such a wind turbine system. The method comprises coordinating the rotational speeds of the plurality of rotors to attenuate oscillations of the support structure caused by the rotating unbalance of the rotors.

A method and system for improving the balance of a rotor in a wind turbine, including; determining blade load data associated with a selected rotor blade pair; determining, based on the blade load data, pitch imbalance data associated with the selected rotor blade pair, wherein the pitch imbalance data associated with a rotor blade pair is based on measurements of at least blade loading, rotor speed and wind speed; and, determining and applying pitch control inputs to one or both of the selected rotor blade pair in order to reduce the severity of the rotor imbalance.

A method for balancing a wind turbine having a vertical axis. The method includes transmitting, via a turbine shaft, mechanical power to an alternator or generator; supporting, via a support structure, a vane shaft and the turbine shaft; and balancing the wind turbine based at least in part on freely moving objects within a hollow chamber of a balancing channel. In some cases, the support structure couples the vane shaft to the turbine shaft. In some cases, the balancing channel is coupled to the vane shaft.

A single-unit nose cone for a ram air including: a dome portion located at a forward end of the single unit nose cone; a dome stand portion adjacent to the dome portion; a seat portion adjacent to the dome stand portion; and a stem portion adjacent to the seat portion and located at an aft end of the single-unit nose cone, wherein the dome portion, the dome stand portion, the seat portion, and the stem portion are composed from a single piece of material having a density of about 0.286 pound/cubic inch (7916 kilogram/cubic meter).

A pitch control system characterized by a hub with at least two blade housings on the hub that are disposed around the hub axis. The blade housings have corresponding blades that engage with them. The blades spiral along housing longitudinal axes toward and away from the hub axis about a segment of helical path to effect a change in the pitch of each blade. One or more elastic members draw the blades toward the hub axis, either directly or indirectly. There are pitch mechanisms effective to facilitate blades to spiral around housing-longitudinal axes. A blade will spiral away from the hub axis when the centrifugal force exerted on the blade exceeds the opposing elastic force in the housing-longitudinal direction (neglecting other forces). Conversely, blades spiral toward the hub axis when said centrifugal force is less than said elastic force. There is an imaginary plane orthogonal to the hub axis. Housing-longitudinal axes have angles with respect to the imaginary plane of not more than 30 degrees.

A method for balancing segmented rotor blades for a wind turbine may include determining a weight for each of a plurality of blade segments, wherein each blade segment extends between a first end and a second and is configured to form a common spanwise section of a segmented rotor blade between the first and second ends. The method may also include determining an initial static moment for each blade segment based on the weight of the blade segment, wherein the initial static moment of at least one of the blade segments differing from the initial static moments of the remainder of the blade segments. Additionally, the method may include adding mass to each of the blade segments to increase the initial static moment for each blade segment to a predetermined static moment, wherein the predetermined static moment is greater than each of the initial static moments of the blade segments.

A floating drum turbine is used for generating the electrical energy from the kinetic energy of a water stream (sea wave or river flow) that provides the mechanical energy needed to rotate an electrical generator for generating the electricity. The drum turbine is installed on a buoyant skid anchored to the seabed by some chains/ropes to keep it in a fixed position and direction along the water stream. The turbine is coupled to an electrical generator with a power transmission system, and generates the electricity that is transferred to the coast using a cable system floated on the water surface.

A method for compensating an imbalance of a wind rotor of a wind turbine includes applying at least one test-offset to a parameter characterizing a state of the wind rotor, wherein the imbalance depends on the parameter; measuring for the at least one test-offset an acceleration of the wind turbine, wherein the acceleration depends on the imbalance; and determining a compensation-offset based on the measured acceleration, wherein the imbalance is at least partially compensated, when the compensation-offset is applied to the parameter. Furthermore, a corresponding wind turbine includes a control unit configured to carry out the above method.

A method of adapting noise emission configurations of plural wind turbines, the method including: determining total wind turbine related noise levels at plural locations; determining, among the plural locations, a critical location having a most critical, in particular highest, total wind turbine related noise level; if the most critical total wind turbine related noise level is above a noise threshold: reducing the noise emission configuration of a wind turbine having the highest noise to power impact ratio, is provided.

A wind turbine comprising a tower, a rotor including a plurality of blades, an electrical generator operatively coupled to the rotor, and a control system including an active damping module configured to monitor oscillatory motion of the wind turbine and to output a damping demand signal to damp the oscillatory motion. The control system is configured to perform a rotor imbalance determination process including: controlling the rotating frequency of the rotor so that it substantially coincides with the natural frequency of the tower, determining rotor imbalance data based on the damping demand signal and evaluating said rotor imbalance data to determine the presence of a rotor imbalance condition, and correcting the rotor imbalance condition by applying pitch control inputs to one or more of the plurality of blades so as to reduce the severity of the rotor imbalance. The invention may also be expressed as a method.