The invention details a method of determining and controlling the attack angle of fixed-speed wind turbine blade aiming at finding out an appropriate angle of attack for optimal extraction of wind energy at low to medium wind speed, which comprises three steps: step 1defining basic parameters of the turbine including the blade length and width, fixed rotational speed, rated wind speed, start-up speed and the lowest speed at which the turbine is forced to stop, and the relationship with the wasted power; step 2defining wind speed based on which a set of attack angles can be calculated to form an overall optimal attack angle of the wind turbine blade; step 3calculate necessary physical parameters to come up with the most effective method of controlling the turbine blade; this invention is applicable to the manufacture of fixed speed wind turbine that can be directly connected to the grid, making wind power costs as low as those of other conventional energy sources.

The vertical axis turbine may include a frame rotatable about the central axis. In one variation at least two masts, each having a boom, are coupled to the frame and at least one sail is coupled to each mast and boom. In another variation, at least two blades are rotatably coupled to the frame and being substantially perpendicular to the frame. The frame may also include at least two retaining members being attached to the frame. Each retaining members defines an opening and corresponds to each mast or blade. A cord is coupled between the two generally opposing booms or blades. The cord extends within the opening of the corresponding retaining members, wherein the cord is configured to regulate the position of the at least one blade or sail. Alternatively, the vertical axis turbine may include a central hub. The cords from each boom or blade extend through each retaining member and then attach to the central hub.

A stability of a vertical axis combined water/wind turbine motor composed of a drag type and a lift type is improved by releasing convex surface resistance produced by a drag-type blade going against a fluid and increasing rotation torque by the reduction in resistance; during high-speed rotation equal to or higher than a fluid speed, all wing surfaces of the drag type are naturally brought into a released state as a result of being pulled by the lift-type blade rotation speed; and a danger at the time of increasing a fluid speed can be avoided by producing a fully-released state by rolling in feathers of a drag-type wind surface configuration, by decreasing the entire volume by folding wing surfaces to the rotation axis side, or by decreasing the entire structure by drawing feathers on the wing surface toward the rotation center.

Rotor blade assemblies and wind turbines are provided. A rotor blade assembly includes a rotor blade having exterior surfaces defining a pressure side, a suction side, a leading edge and a trailing edge each extending between a tip and a root, the rotor blade defining a span and a chord, the exterior surfaces defining an interior of the rotor blade. The rotor blade assembly further includes a loading assembly, the loading assembly including a weight disposed within the interior and movable generally along the span of the rotor blade, the weight connected to a rotor blade component such that movement of the weight towards the tip causes application of a force to the rotor blade component by the weight. Centrifugal force due to rotation of the rotor blade biases the weight towards the tip.

A rotor blade of a wind turbine, comprising a first rotor-blade portion and a second rotor-blade portion. In this case, the first and the second rotor-blade portion constitute a total length of the rotor blade and, upon a rotation of the rotor blade, the first rotor-blade portion and the second rotor-blade portion can be moved relative to each other, along a longitudinal axis of the rotor blade, as a result of a centrifugal force acting upon the rotor blade, in such a way that the total length of the rotor blade can be altered.

The present invention presents a structure for a set of cable-stayed blades for variable-speed wind turbines with the aim of manufacturing low-cost, large-capacity wind turbines with blades of up to 200 meters long, do not rotate to change the tilt of the wing, insulated from turbine shaft, the structure includes the steel tube at the center of the central hub for affixing the blade set onto the head of the wind turbine shaft, a tower to extend the turbine vertical axis for mounting stay cables which are fastened to the axial bearing blade frame, the blade body consists of a triangular prismatic frame with two rear-framing tubes parallel to each other to form the baselines for mounting blade surface sheets which can be furl/unfurled, the blades can be disassembled and placed into containers to be transported to the base of the turbine tower for assembly.

An energy generating device for generating energy from a flowing fluid, especially from a wind flow and/or from a water flow, comprises: a rotation body, the rotation body extending along an axis of rotation between a first point and a second point and the rotation body being adapted to rotate about the axis of rotation and the rotation body being formed from at least a first, a second, and a third rotation segment, wherein the rotation segments are joined together and arranged along the axis of rotation, and they form a region at least partly surrounded by fluid, wherein the second rotation segment is situated between the first and the third rotation segment and has a different diameter than the first and third rotation segment; and a generator device mechanically connected to the rotation body, wherein the generator device is adapted to generate energy which is produced from the rotation of the rotation body.

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.