Abstract: A wind turbine with a rotor mounted on a hub section, wherein the rotor comprises a plurality of blades, at least one of which comprises a main blade section, which is optionally pitchable, and an auxiliary blade section mounted to the hub section. The auxiliary blade section is arranged in the area of a leading edge or of a trailing edge of the main blade, so that each blade is thereby provided with a leading edge slat or a trailing edge flap formed by the auxiliary blade section to increase the planform area of the blade and increase aerodynamic lift. A control method for a wind turbine controls a main blade section and an auxiliary blade section to provide different angles of attack to reduce undesired loads at sudden extreme changes of wind speed, e.g. during idling of the wind turbine. In a separate aspect, the invention provides a wind turbine having a blade with a non-pitchable leading edge slat, which extends at most 40% of the radius of the rotor in a longitudinal direction of the blade.

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: 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 wind turbine with a rotor mounted on a hub section, wherein the rotor comprises a plurality of blades, at least one of which comprises a main blade section, which is optionally pitchable, and an auxiliary blade section mounted to the hub section. The auxiliary blade section is arranged in the area of a leading edge or of a trailing edge of the main blade, so that each blade is thereby provided with a leading edge slat or a trailing edge flap formed by the auxiliary blade section to increase the planform area of the blade and increase aerodynamic lift. A control method for a wind turbine controls a main blade section and an auxiliary blade section to provide different angles of attack to reduce undesired loads at sudden extreme changes of wind speed, e.g. during idling of the wind turbine. In a separate aspect, the invention provides a wind turbine having a blade with a non-pitchable leading edge slat, which extends at most 40% of the radius of the rotor in a longitudinal direction of the blade.

Abstract: A wind turbine blade comprising an active elastic member arranged with access to the surface of the wind turbine blade is provided. The active elastic member is deformable from a first shape to a second shape and the lift coefficient of the airfoil with the active elastic member in the first shape is larger than the lift coefficient of the airfoil with the active elastic member in the second shape. Furthermore, a wind turbine comprising such a wind turbine blade and a method of operating a wind turbine comprising such a wind turbine blade are provided.

Abstract: A wind turbine comprising a wind turbine blade with high lift and/or low solidity is provided. The blade is directed towards pitch regulated wind turbines, which are operated at variable rotor speed and have blades longer than about 30 meters. The blade is for example advantageous in that it may provide reduced extreme and fatigue loads at the same or near the same power production.

Abstract: An aerodynamic profile and a wind turbine comprising a wind turbine blade with reduced sensitivity towards surface irregularities are provided. The invention is mainly directed towards pitch-regulated wind turbines, which are operated at variable rotor speed and have blades longer than about 30 meters.

Abstract: A method for operating a wind turbine having a rotor with a number of wind turbine blades, wherein the rotor's axis of rotation is tilted in relation to the direction of the incoming wind, includes the steps of determining the azimuth angle (A) of the blades and adjusting the pitch angle of the blades in accordance with the azimuth angle (A) to ensure a substantially constant angle of attack (AoA) during at least a full rotation of the rotor. A wind turbine and use of the method are also contemplated.

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 having a rotor with a number of wind turbine blades, wherein the rotor's axis of rotation is tilted in relation to the direction of the incoming wind, includes the steps of determining the azimuth angle (A) of the blades and adjusting the pitch angle of the blades in accordance with the azimuth angle (A) to ensure a substantially constant angle of attack (AoA) during at least a full rotation of the rotor. A wind turbine and use of the method are also contemplated.

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: A wind turbine includes a rotor with wind turbine blades each having a root end connected to a hub of the wind turbine and a tip end, the tip end of each of which being equipped with a winglet extending a distance in a direction perpendicularly to a longitudinal direction of the blade. A new and much more slim design of the outer part of the wind turbine blade is disclosed, i.e. with a shorter chord length designed within a narrow band of values defined with respect to the length of the winglet, i.e. the extension in the direction transverse to the longitudinal direction of the blade.

Abstract: The invention relates to a pitch controlled wind turbine blade including a pressure surface side and a leeward surface side, where the surfaces establishes a leading edge and a trailing edge. The blade includes a turbulence generating mechanism where the mechanism is placed on the leeward surface sides of the wind turbine blade and at the outer section of the wind turbine blade in direction of the blade tip. The invention further relates to a wind turbine including at least two pitch controlled wind turbine blades and a pitch controlling mechanism for pitching the blades. The blades include a turbulence generating mechanism where the mechanism is placed on the leeward surface sides of the wind turbine blades and at the outer section of the wind turbine blades in direction of the blade tips.

Abstract: An advantageous new design of a wind turbine blade and rotor is obtained by providing one, two or more parallel rows of sub-boundary layer vortex generators, whereby a blade is obtained, which is resistant to stall and provides for a high maximum lift coefficient CL,max of the blades and a slender blade design, a low socalled radius specific solidity of the rotor. The very high lift coefficient CL can reduce the necessary blade area and loads or/and increase the length of the blade and maintain the original loads with higher production. The row or rows of sub-boundary layer vortex generators are in a preferred embodiment of the invention provided in combination with Gurney Flaps generating a very high lift coefficient CL with a relative gentle stall at very high angle of attack.

Abstract: A method for operating a wind turbine having a rotor with a number of wind turbine blades, wherein the rotor's axis of rotation is tilted in relation to the direction of the incoming wind, includes the steps of determining the azimuth angle (A) of the blades and adjusting the pitch angle of the blades in accordance with the azimuth angle (A) to ensure a substantially constant angle of attack (AoA) during at least a full rotation of the rotor. A wind turbine and use of the method are also contemplated.

Abstract: An advantageous new design of a wind turbine blade and rotor is obtained by providing one, two or more parallel rows of sub-boundary layer vortex generators, whereby a blade is obtained, which is resistant to stall and provides for a high maximum lift coefficient CL,max of the blades and a slender blade design, a low socalled radius specific solidity of the rotor. The very high lift coefficient CL can reduce the necessary blade area and loads or/and increase the length of the blade and maintain the original loads with higher production. The row or rows of sub-boundary layer vortex generators are in a preferred embodiment of the invention provided in combination with Gurney Flaps generating a very high lift coefficient CL with a relative gentle stall at very high angle of attack.

Abstract: A wind turbine includes a rotor with wind turbine blades each having a root end connected to a hub of the wind turbine and a tip end, the tip end of each of which being equipped with a winglet extending a distance in a direction perpendicularly to a longitudinal direction of the blade. A new and much more slim design of the outer part of the wind turbine blade is disclosed, i.e. with a shorter chord length designed within a narrow band of values defined with respect to the length of the winglet, i.e. the extension in the direction transverse to the longitudinal direction of the blade.

Abstract: An aerodynamic profile and a wind turbine comprising a wind turbine blade with reduced sensitivity towards surface irregularities are provided. The invention is mainly directed towards pitch-regulated wind turbines, which are operated at variable rotor speed and have blades longer than about 30 meters.

Abstract: A wind turbine blade comprising an active elastic member arranged with access to the surface of the wind turbine blade is provided. The active elastic member is deformable from a first shape to a second shape and the lift coefficient of the airfoil with the active elastic member in the first shape is larger than the lift coefficient of the airfoil with the active elastic member in the second shape. Furthermore, a wind turbine comprising such a wind turbine blade and a method of operating a wind turbine comprising such a wind turbine blade are provided.

Abstract: A wind turbine comprising a wind turbine blade with high lift and/or low solidity is provided. The blade is directed towards pitch regulated wind turbines, which are operated at variable rotor speed and have blades longer than about 30 meters. The blade is for example advantageous in that it may provide reduced extreme and fatigue loads at the same or near the same power production.