A wind turbine (1) comprising a tower (2), a nacelle (3) and a hub (7) is disclosed. The hub (7) comprises a blade canying structure (4) with one or more wind turbine blades (5) connected thereto. Each of the wind turbine blades (5) is connected to the blade canying structure (4) via a hinge (6) at a hinge position of the wind turbine blade (5), each wind turbine blade (5) thereby being arranged to perform pivot movements relative to the blade carrying structure (4) between a minimum pivot angle and a maximum pivot angle. The wind turbine (1) further comprises a stop mechanism arranged to move the wind turbine blades (5) to a safe pivot angle in the case of an emergency, the stop mechanism comprising a release mechanism (8, 12, 14) and at least one wire (9, 10) interconnecting the release mechanism (8, 12, 14) and each of the wind turbine blades (5). Activation of the release mechanism (8, 12, 14) causes an abrupt change in a pulling force applied to the wind turbine blades (5) by the wire(s) (9, 10), the change in pulling force causes the wind turbine blades (5) to move immediately to the safe pivot angle.

A wind turbine is provided. The turbine includes a support having an axis of rotation, a generator, a plurality of blades rotatably mounted on the support about the axis of rotation, the blades being moveable between a retracted position generally parallel with the axis of rotation and a fully deployed position generally perpendicular with the axis of rotation, the blades being connected to the generator such that rotation of the blades in a direction induced by wind causes the generator to produce electricity, and the provision of electricity to the generator rotates the blades, and a controller connected to the generator and configured to deliver a flow of current to the generator that is sufficient to move the blades from the retracted position toward the fully deployed position and insufficient to move the blades all the way to the fully deployed position. The flow of current induces rotation of the blades in the direction induced by wind, which creates a centrifugal force that moves the blades from the retracted position toward the fully deployed position. As the blades move from the retracted position, the blades have increasing exposure to ambient wind to receive additional rotational force from ambient wind, and the additional rotational force being sufficient to, either alone or in combination with the flow of current, move the blades into the fully deployed position.

Provided are a control method and apparatus for load reduction of a wind turbine. The control method for load reduction includes: determining a representative blade root load value of a wind turbine; determining an additional pitch rate value based on the representative blade root load value; determining a pitch rate control value based on a given pitch rate value and the additional pitch rate value: and applying the pitch rate control value to each blade of the wind turbine, to control each blade of the wind turbine to perform a pitch action.

A wind turbine blade (6) having a span-wise direction between an inner tip region (6a) and an outer tip region (6b), and a chord-wise direction (AA) perpendicular to the span-wise direction is disclosed. The wind turbine blade (6) comprises a hinge (7), an outer blade part (8) and an inner blade part (9). The hinge (7) is arranged to connect the wind turbine blade (6) to a blade carrying structure (5) of a wind turbine (1). The hinge (7) is arranged at a distance from the inner tip region (6a) and at a distance from the outer tip region (6b). The outer blade part (8) is arranged between the hinge (7) and the outer tip region (6b) and the inner blade part (9) is arranged between the hinge (7) and the inner tip region (6a). The inner blade part (9) comprises at least two inner blade portions (20) each having a profile and wherein the inner blade portions (20) are arranged such that the profiles are spaced from each other in the chord-wise direction (AA).

The lengths and/or chords and/or pitches of wind turbine or propeller blades are individually established, so that a first blade can have a length/chord/pitch that is different at a given time to the length/chord/pitch of a second blade to optimize performance and/or to equalize stresses on the system.

A structure adapted to traverse a fluid environment includes an elongate body having a root, a wingtip, a leading edge and a trailing edge; and a rigid winglet associated with the wingtip and having a winglet body extending substantially normal to one of a suction side and a pressure side of the elongate body to a termination point that is rearward of the trailing edge. In an embodiment, the structure is a rotor blade that may be incorporated into a wind turbine.

Wind turbine blade comprising at least one deformable trailing edge section having a plurality of actuators consecutively arranged substantially downstream from one another and a control system for controlling the actuators, wherein a downstream end of one actuator is connected by a substantially rigid link with an upstream end of the next actuator and the plurality of actuators comprises an upper actuator being mounted above a chord line of the blade section and a lower actuator being mounted below a chord line of the blade section. Wind turbines comprising such a blade and methods of controlling loads on a wind turbine blade are also described.

A wind turbine is provided. The turbine includes a support having an axis of rotation, a generator, a plurality of blades rotatably mounted on the support about the axis of rotation, the blades being moveable between a retracted position generally parallel with the axis of rotation and a fully deployed position generally perpendicular with the axis of rotation, the blades being connected to the generator such that rotation of the blades in a direction induced by wind causes the generator to produce electricity, and the provision of electricity to the generator rotates the blades, and a controller connected to the generator and configured to deliver a flow of current to the generator that is sufficient to move the blades from the retracted position toward the fully deployed position and insufficient to move the blades all the way to the fully deployed position. The flow of current induces rotation of the blades in the direction induced by wind, which creates a centrifugal force that moves the blades from the retracted position toward the fully deployed position. As the blades move from the retracted position, the blades have increasing exposure to ambient wind to receive additional rotational force from ambient wind, and the additional rotational force being sufficient to, either alone or in combination with the flow of current, move the blades into the fully deployed position.

This application provides a control method and device for avoiding run-away, and a wind turbine. The method may include: determining whether a brake system of the wind turbine has failed; if the brake system has failed, calculating an initial crosswind position based on a current wind direction angle, and enabling a yaw system of the wind turbine to perform a crosswind operation based on the initial crosswind position; performing a long-period and short-period filter processing on wind direction data acquired during a crosswind process to obtain an average and instantaneous wind direction angle respectively; determining whether a wind direction has a sudden change based on the average and instantaneous wind direction angle; and if the wind direction has a sudden change, calculating a new crosswind position based on the average wind direction angle, and enabling the yaw system to perform a crosswind operation based on the new crosswind position.

Described is a system for monitoring deflection of turbine blades of a wind turbine comprising a tower. The system comprises a position detecting apparatus mounted to the wind turbine, the position detection apparatus comprising position detection components each detecting a presence or absence of a corresponding one of the segments of the turbine blades; and a deflection controller configured to receive the presence or absence detection and to use the presence or absence detection to determine a distance of each of the segments of the turbine blades relative to the tower, whereby the distance of each of the segments of the turbine blades relative to the tower is representative of the deflection of the turbine blades.