The invention relates to a method for measuring and correcting the angle of attack in a wind turbine farm (11), by which means the yield of each wind turbine (11) of the wind farm is measured initially in order to be able to define a model wind turbine which will be the one which generates the maximum power. The creation of coordinate axes for each blade (15) of the wind turbine (10) allows the angle of attack of the blades (15) of said model wind turbine (10) to be calculated and a reference value to be defined in order to copy same to each blade (15) of the rest of the wind turbines (11), in such a way that the optimum power ratio is obtained for each wind turbine of the wind farm.

Provided is a method of controlling a pitch angle of at least one blade of a wind turbine by use of a hydraulic system, the hydraulic system including at least one reservoir configured to store a hydraulic fluid, and at least one pump configured to supply the hydraulic fluid from the reservoir to at least one accumulator, if a hydraulic fluid pressure in the accumulator falls below a lower threshold value and till the hydraulic fluid pressure in the accumulator exceeds an upper threshold value. The accumulator is configured to store the pressurized hydraulic fluid supplied by the pump and to supply the pressurized hydraulic fluid to at least one pitch control cylinder of the hydraulic system via at least one output valve of the hydraulic system. The pressurized hydraulic fluid in the pitch control cylinder drives at least one piston to change the pitch angle of the blade.

Soundness and a sign of abnormality of a pitch mechanism of a wind turbine blade is quantitatively diagnosed. A method of diagnosing a wind turbine power generation facility includes the steps of: rotating and fixing a wind turbine rotor including at least one wind turbine blade; providing, in a state where the wind turbine rotor is fixed, a pitch control command value to a pitch mechanism that changes a pitch angle of the wind turbine blade, to increase or reduce the pitch angle such that the pitch angle reaches a pitch angle target value from a reference angle; acquiring an actual pitch angular velocity or an actual pitch angle of the wind turbine blade corresponding to the pitch control command value; and diagnosing soundness of the pitch mechanism based on correlation between the acquired actual pitch angular velocity or the acquired actual pitch angle, and the pitch control command value.

There is presented a method (320) for controlling a wind turbine (100), wherein said wind turbine comprises a wind turbine rotor (102) with one or more blades (103), wherein the wind turbine has a rated angular rotation speed (214) of the wind turbine rotor, said method comprising providing (322) an estimated drop size (324) of rain drops impinging on the one or more blades, determining (326) whether an entry criterion for operation according to a reduced mode is fulfilled, wherein said determining is based at least partially on the estimated drop size (324), controlling (328) the wind turbine according to the reduced mode if the entry criterion is fulfilled, wherein in the reduced mode an angular rotation speed of the wind turbine rotor is limited below an angular rotation speed threshold (216), wherein the angular rotation speed threshold is smaller than the rated angular rotation speed of the wind turbine.

Described and shown is a process for preparing an emergency energy storage device, with at least one energy storage element for operation, whereby the emergency energy store is designed to provide emergency electrical energy for at least one energy consumer, whereby the energy (E.sub.L) which can be drawn from the emergency energy storage and/or the peak output (P.sub.max) which can be drawn from the emergency energy storage is determined and the operational readiness is established as soon as the energy (E.sub.L) which can be drawn from the emergency energy storage and/or the peak output (P.sub.max) which can be drawn from the emergency energy storage has reached a definable minimum energy value. A process for preparing an emergency energy storage device for operation in which the emergency energy storage is discharged via a discharging device and the heat occurring at the internal resistance (R.sub.i) is used to heat the emergency energy storage device.

The invention relates to a wind turbine system (1) with several wind turbine modules (2) mounted to a support structure (3). A control system is configured to determine a lift command (21) for a particular wind turbine module (2′) of the 5 plurality of wind turbines modules (2). The control system is applying the lift command (21) to a corresponding rotor blade pitch adjustment system of the particular wind turbine module (2′) so as to create a lift force (F_up) in the opposite direction of gravity on the particular wind turbine module mounted on the support structure. Providing an upwards lift force on one, or more, particular 10 wind turbine module(s) may reduce, or eliminate, static and/or dynamical loads from the wind turbine module on the support structure.

A method for controlling a wind turbine is disclosed, the wind turbine comprising a set of wind turbine blades (1), each wind turbine blade (1) being provided with at least one air deflector (2) being movable between an activated position in which it protrudes from a surface of the wind turbine blade (1) and a de-activated position. The occurrence of an event causing a change in operational conditions is registered, and a new operating state for the wind turbine is determined, the new operating state meeting requirements of the changed operational conditions. The air deflectors (2) of the wind turbine blades (1) and pitch angles of the wind turbines blades (1) are controlled in order to reach the new operating state for the wind turbine, and in such a manner that the control of the pitch angles of the wind turbine blades (1) is performed while taking information regarding the control of the air deflectors (2) into account.

A wind turbine control system comprising a controller of a control mechanism of a wind turbine, wherein the controller implements a computerized real-time blade model to calculate operational parameters of the controller, and wherein the computerized real-time blade model receives as inputs a determined wind turbine operating point and a rotor-plane wind speed value that is estimated in real-time. In another aspect, the embodiments of the invention provide a method of controlling a control mechanism of a wind turbine. Advantageously, the invention provides a more flexible and responsive control system that is able to adapt to changing wind conditions even if those wind conditions are beyond what is usually predicted.

A method for controlling the pitch angle of the blades including the following steps of: measuring an energy storage of the blades pitch actuation system at predefined values of a first blade pitch angle interval; comparing the measured values of the energy storage of the blades pitch actuation system with a predefined minimum value of the energy storage; if the measured values of the energy storage are all greater or equal than the predefined minimum value of the energy storage then enabling normal operation; if at least one of the measured values of the energy storage are lower than the predefined minimum value then: calculating a third pitch angle calculating a third blade pitch angle interval extending between a fourth pitch angle and the second pitch angle; and limiting the blades pitch actuation system to operate only in the third pitch angle interval.

A turbine, in particular for harvesting energy in flowing air or flowing water, is easily adaptable to different application conditions and facilitating a comparably high degree of efficiency. This is achieved in that the basic shape of the turbine is cylindrical and is provided with blades which are parallel to an axis of the turbine. The blades are pivotally arranged in joints on the outer circumference of at least one turbine wheel. The blades are substantially L-shaped. The longer limb of the blade is curved preferably in a manner corresponding to the radius of the turbine casing, and the shorter limb lies within the surface line of the turbine.