Abstract: A method for operating a wind turbine includes: providing a curve defining optimal pitch angle as a function of tip speed ratio or as a function of wind speed; modifying at least a part of the optimal pitch angle curve by applying a safety buffer, thereby obtaining a safety modified pitch angle curve; operating the wind turbine in accordance with the safety modified pitch angle curve; measuring one or more parameters regarding wind conditions and/or loads on one or more component of the wind turbine; adjusting the safety buffer, based on the measurements, thereby obtaining an adjusted pitch angle curve; and operating the wind turbine in accordance with the adjusted pitch angle curve. Since the safety buffer is adjusted based on measured parameters, it can be reduced if actual operating conditions are less severe than expected. This allows the wind turbine to be operated in a more optimal manner.

Abstract: A wind turbine having at least one trailing edge control surface (10) on at least one rotor blade (5) is operated in a first mode, in which a rotor blade angle of attack and a trailing edge control surface deflection are set according to one or more wind turbine control parameters. The turbine is selectively operated in a second, noise reduced, mode, in which for a given set of wind turbine control parameters, the trailing edge control surface deflection is increased towards the pressure side and the rotor blade angle of attack is decreased with respect to the first mode. In the second mode, for a given set of control parameters, the loading on the blade (5) is on average closer to a hub than in the first operating mode.

Abstract: Methods and systems [are disclosed] for controlling wind turbines having a tower, a nacelle, and a rotor with a blade and hub. The wind turbine may further include a yaw drive system for rotating the nacelle relative to the tower about a substantially vertical axis, and/or a pitch drive system for rotating the blade of the rotor around a longitudinal axis of the blade. During high wind speeds when the wind turbine may be in a stand-still and non-power-producing situation, the yaw drive system may continuously or periodically rotate the nacelle to vary a direction of the rotor with respect to the wind. Further, the pitch drive system may continuously or periodically rotate the blade to vary a direction of the blade with respect to the wind. In this manner, the wind turbine may be safely controlled during high winds.

Abstract: A method for controlling operation of a wind turbine and a method for controlling operation of a plurality of wind turbines positioned in a wind farm are disclosed. According to the method, a pitch and rotational speed curve, e.g. a ? versus ? curve, is selected from a group of pitch and rotational speed curve, and the wind turbine is operated in accordance with the selected curve for a short period, while monitoring at least one target parameter, e.g. power production or loads on one or more components. This is repeated for each of the curves of the group of pitch and rotational speed curves. This is also repeated a predetermined number of times, i.e. each curve is selected in turn a predetermined number of times. Based on the monitored target parameters an optimum curve is determined from the group of pitch and rotational speed curve, and the wind turbine is operated in accordance with this optimum curve.

Abstract: A method for operating a wind turbine is disclosed. The wind turbine comprises a rotor having a set of wind turbine blades, said rotor being mounted on a tower. The method comprises the steps of: Providing a curve defining optimal pitch angle as a function of tip speed ratio for the wind turbine blades or as a function of wind speed. Modifying at least a part of said optimal pitch angle curve by applying a safety buffer, e.g. at tip speed ratios and/or pitch angles where there is a risk that the blades may stall and/or that overload is caused to the wind turbine, thereby obtaining a safety modified pitch angle curve. Operating the wind turbine in accordance with the safety modified pitch angle curve. Measuring one or more parameters providing information regarding wind conditions and/or loads on one or more components of the wind turbine, during operation of the wind turbine.

Abstract: The invention relates to a method of controlling a wind turbine comprising a tower, a nacelle located on the tower, and a rotor mounted on the nacelle and comprising a hub and at least one blade, the wind turbine further comprising a yaw drive system for rotating the nacelle in relation to the tower about a substantially vertical axis, and/or a pitch drive system for rotating the blade around a longitudinal axis there of the method comprising, during a stand-still, non-power-producing situation of the wind turbine due to high wind speeds, continuously or periodically rotating, by means of the yaw drive system, the nacelle so as to vary the direction of the wind in relation to the rotor, and/or continuously or periodically rotating, by means of the pitch drive system, the blade so as to vary the direction of the wind in relation to the blade.

Abstract: A method for controlling operation of a wind turbine and a method for controlling operation of a plurality of wind turbines positioned in a wind farm are disclosed. According to the method, a pitch and rotational speed curve, e.g. a ? versus ? curve, is selected from a group of pitch and rotational speed curve, and the wind turbine is operated in accordance with the selected curve for a short period, while monitoring at least one target parameter, e.g. power production or loads on one or more components. This is repeated for each of the curves of the group of pitch and rotational speed curves. This is also repeated a predetermined number of times, i.e. each curve is selected in turn a predetermined number of times. Based on the monitored target parameters an optimum curve is determined from the group of pitch and rotational speed curve, and the wind turbine is operated in accordance with this optimum curve.

Abstract: A method of controlling a wind turbine, where a control signal for a controllable parameter of the wind turbine is determined, and the rotor power coefficient, the torque coefficient, and/or a thrust coefficient of the wind turbine are estimated at time intervals. From this is determined a variation parameter reflecting the variation of the estimated rotor power, torque or thrust coefficient over time. The wind turbine is then controlled according to the control signal only if the variation parameter is below an alert threshold, and otherwise according to a modified control strategy. The control signal may have a power or torque reference signal for controlling the rotational speed of the turbine or a blade pitch reference signal. The modified control method may for instance entail stopping or de-rating the wind turbine. A control system configured to perform the above control method, and a wind turbine comprising such system are also disclosed.

Abstract: An active flow control device (10) and a method for affecting a fluid boundary layer of a wind turbine blade (100) are disclosed, as well as a stand-alone module (40) including a plurality of such devices and a wind turbine blade comprising a such devices and/or modules. One or more flow effectors (14) are rotatable back and forth in an oscillating movement (A) in a rotational plane. The flow effectors (14) are also movable in a direction transverse to the rotational plane between a retracted position and an extended position.

Abstract: The invention relates a wind turbine rotor. The rotor comprises at least one wind turbine blade, at least one image capturing device, and one or more markers arranged on the blade so that the at least one image capturing device may detect the position of the markers. The invention further relates to a wind turbine and use thereof.

Abstract: A method of controlling a wind turbine, where a control signal for a controllable parameter of the wind turbine is determined, and the rotor power coefficient, the torque coefficient, and/or a thrust coefficient of the wind turbine are estimated at time intervals. From this is determined a variation parameter reflecting the variation of the estimated rotor power, torque or thrust coefficient over time. The wind turbine is then controlled according to the control signal only if the variation parameter is below an alert threshold, and otherwise according to a modified control strategy. The control signal may have a power or torque reference signal for controlling the rotational speed of the turbine or a blade pitch reference signal. The modified control method may for instance entail stopping or de-rating the wind turbine. A control system configured to perform the above control method, and a wind turbine comprising such system are also disclosed.

Abstract: A wind turbine blade includes a blade body and lift-regulating mechanism adapted for movement in relation to the blade body by at least one actuation mechanism controlled by an actuation controller. The actuation controller controls a setting of the lift-regulating mechanism based on an input from a sensor, and the sensor is a force sensor adapted for sensing a force from a wind flow acting on the lift-regulating mechanism, whereby a wind turbine blade with fast-responding lift-regulating mechanism is provided.