Abstract: A method of controlling a wind turbine having a nacelle, a rotor, a rotating hub, a first rotor blade and at least a second rotor blade, both rotor blades being mounted to the hub. The method includes measuring the strain in the first rotor blade by a strain measurement device attached to the first rotor blade; and choosing the operational parameters of the wind turbine based on the measured strain such that fatigue damage of the second rotor blade is reduced. A wind turbine is controlled by such a method.

Abstract: A method of controlling a wind turbine having a nacelle, a rotor, a rotating hub, a first rotor blade and at least a second rotor blade, both rotor blades being mounted to the hub. The method includes measuring the strain in the first rotor blade by a strain measurement device attached to the first rotor blade; and choosing the operational parameters of the wind turbine based on the measured strain such that fatigue damage of the second rotor blade is reduced. A wind turbine is controlled by such a method.

Abstract: A swept wind turbine blade (20) includes a blade body (24) extending along a length between a root (26) and a tip (28) of the blade (20). A pitch axis (36) extends through the root (26) of the blade (20). A reference line (48) defines a deviation from the pitch axis (36) and corresponds to a swept shape of the blade (20) along its length. The reference line (48) has a zero sweep at the root (26), a zero slope at the root (26), and a positive curvature (66) along a segment within 25% of the length from the root (26) to the tip (28) of the blade (20).

Abstract: A wind turbine blade airfoil trailing edge (TE) with a first waveform profile (44B, 44C, 44E) as seen from behind, formed by ruffles or alternating ridges (21) and valleys (22) formed on the airfoil (20) and ending at the trailing edge. The trailing edge may further include a second waveform profile (48B, 48C, 48E) as seen from above, resulting from serrations formed by an oblique termination plane (32B) of the trailing edge or by other geometry. The ridges and/or serrations may be asymmetric (44E, 48E) to increase a stall fence effect of the ridges on the suction side (SS) of the trailing edge. The first and second waveforms may have the same period (44B, 48B) or different periods (44C, 48C).

Abstract: A wind turbine blade (22) is cantilevered from a shaft (50) of a rotor (20). A pitch reference azimuth (74) of the blade may be located by generating a function (66, 67, 68, 69) of gravitational bending strain or moment magnitude of the blade versus pitch angle of the blade for a vector component (85, 86) of gravitational force (GF) relative to a predetermined transverse line (CL, 83) of the blade, such as a chord line, over a range of pitch angles of the blade. The pitch reference azimuth may be set at a characteristic point (70, 71, 72) on the function, such as an inflection point Two such functions (67, 69) may be generated with the blade in two respective positions on opposite sides of the rotor The intersection point (73) of these functions is a pitch reference point that is compensated for rotor tilt.

Abstract: A method and system for improving power production efficiency on a wind farm having of a plurality of spatially distributed wind turbines is provided. The method includes receiving a wind measurement that includes a wind direction impinging on a turbine (20), determining a misalignment of the wind turbine with respect to the wind direction, and activating a wake steering control for the wind turbine (20) to implement the misalignment of the wind turbine (20) with the wind direction such that the misalignment is adapted to steer a wake of the wind turbine away from a neighboring wind turbine (30). A wind turbine arrangement including a nacelle, a yaw controller, and a yaw drive is also provided.

Abstract: A wind turbine blade (80, 82) having a spanwise series of vortex generators (26, 28, 26P, 28P, 64, 66) and having a trailing edge (42) defining a waveform. The vortex generators are aligned with a predetermined position or phase (44, 46) of a respective period of the trailing edge waveform. Each vortex generator may be designed to create a vortex (27, 29) that crosses the trailing edge at an angle of less than 30 degrees from parallel to the trailing edge. The blade may include alternating ridges (52) and troughs (54) that end at the waveform trailing edge. A front end of each trough may form a V-shaped drop-off in the suction side of the blade that forms a pair (64, 66) of vortex generators to create counter-rotating vortices within the trough that entrain energy to the bottom of the trough.

Abstract: A method for controlling aerodynamic loads in wind turbine (20), includes stopping rotation of blades (22) of the turbine about a rotor shaft axis (38); stopping rotation of a nacelle (30) of the turbine about a vertical yaw axis (36); pitching each blade of the turbine about its respective pitch axis (43) into a stable pitch angle range (52B-52C or 52E-52F) in which a resulting root twisting moment (52) created by a current wind loading (48, 50) on the respective blade is in a direction urging pitch rotation of the blade toward a position of lower root twisting moment; and releasing the blades to rotate passively about their respective pitch axes during subsequent changing wind directions (VR1). A blade may be designed to better align a root zero twisting moment (52A, 52D) in the stable pitch angle range with a minimum (48B, 48D, 50B, 50D) wind loading.

Abstract: A wind turbine blade (162) and a method of forming a wind turbine blade. The method includes: forming an inner segment (10) of an airfoil, leaving a portion (16) of an inner weave (12) extending from the inner segment; forming an outer segment (18) of the airfoil, leaving a portion (24) of an outer weave (20) extending from the outer segment; overlapping the extending portion of the inner weave with the extending portion of the outer weave; infusing the overlapped extending portions with additional resin; and curing the additional resin to form a monolithic airfoil (160).

Abstract: One or more air nozzles (31) create respective air jets (34) angled radially from a blunt trailing edge (22) of a wind turbine blade (20A-G). The jets create and maintain a radially flowing airstream (36) along the trailing edge that extinguishes vortex shedding (28). This reduces drag and noise, thus allowing blades to have an extensive blunt trailing edge, which increases resistance to buckling, thus enabling longer blades. The jets may be supplied by airflow from an air intake in a blade chamber (44), or a ram air intake (40), or a compressor (54). Each nozzle may be individually metered (60) and/or individually or group valved (58) to provide a particular airflow to each nozzle relative to the other nozzles.

Abstract: A method of forming a wind turbine component, the method including forming a segment (10, 12) by impregnating a portion (18, 20) of a fiber reinforcement (50) with a thermoset resin (60) up to a boundary (56), curing the thermoset resin, and leaving unimpregnated fiber reinforcement (22) extending from the boundary. The component may then be assembled by impregnating and joining the unimpregnated fiber reinforcement of two such segments.

Abstract: A wind turbine blade (80, 82) having a spanwise series of vortex generators (26, 28, 26P, 28P, 64, 66) and having a trailing edge (42) defining a waveform. The vortex generators are aligned with a predetermined position or phase (44, 46) of a respective period of the trailing edge waveform. Each vortex generator may be designed to create a vortex (27, 29) that crosses the trailing edge at an angle of less than 30 degrees from parallel to the trailing edge.

Abstract: A wind turbine blade airfoil trailing edge (TE) with a first waveform profile (44B, 44C, 44E) as seen from behind, formed by ruffles or alternating ridges (21) and valleys (22) formed on the airfoil (20) and ending at the trailing edge. The trailing edge may further include a second waveform profile (48B, 48C, 48E) as seen from above, resulting from serrations formed by an oblique termination plane (32B) of the trailing edge or by other geometry. The ridges and/or serrations may be asymmetric (44E, 48E) to increase a stall fence effect of the ridges on the suction side (SS) of the trailing edge. The first and second waveforms may have the same period (44B, 48B) or different periods (44C, 48C).

Abstract: A wind turbine blade (22) is cantilevered from a shaft (50) of a rotor (20). A pitch reference azimuth (74) of the blade may be located by generating a function (66, 67, 68, 69) of gravitational bending strain or moment magnitude of the blade versus pitch angle of the blade for a vector component (85, 86) of gravitational force (GF) relative to a predetermined transverse line (CL, 83) of the blade, such as a chord line, over a range of pitch angles of the blade. The pitch reference azimuth may be set at a characteristic point (70, 71, 72) on the function, such as an inflection point Two such functions (67, 69) may be generated with the blade in two respective positions on opposite sides of the rotor The intersection point (73) of these functions is a pitch reference point that is compensated for rotor tilt.

Abstract: A method of forming a wind turbine component, the method including forming a segment (10, 12) by impregnating a portion (18, 20) of a fiber reinforcement (50) with a thermoset resin (60) up to a boundary (56), curing the thermoset resin, and leaving unimpregnated fiber reinforcement (22) extending from the boundary. The component may then be assembled by impregnating and joining the unimpregnated fiber reinforcement of two such segments.

Abstract: A power producing spinner (28) for a wind turbine (10), the wind turbine (10) having a plurality of blades (18) interconnected about an axis of rotation (30) by a hub (20). The power producing spinner (28) includes an aerodynamic shape (34) extending radially outward from the axis of rotation (30) to define an upwind airfoil portion (40) disposed upwind of an inboard portion (42) of each blade (18) of the wind turbine (10). The power producing spinner (28) is effective to extract energy from an air flow (44) flowing over the spinner (28) and to increase an aerodynamic efficiency of the blades (18).

Abstract: A method for controlling aerodynamic loads in wind turbine (20), includes stopping rotation of blades (22) of the turbine about a rotor shaft axis (38); stopping rotation of a nacelle (30) of the turbine about a vertical yaw axis (36); pitching each blade of the turbine about its respective pitch axis (43) into a stable pitch angle range (52B-52C or 52E-52F) in which a resulting root twisting moment (52) created by a current wind loading (48, 50) on the respective blade is in a direction urging pitch rotation of the blade toward a position of lower root twisting moment; and releasing the blades to rotate passively about their respective pitch axes during subsequent changing wind directions (VR1). A blade may be designed to better align a root zero twisting moment (52A, 52D) in the stable pitch angle range with a minimum (48B, 48D, 50B, 50D) wind loading.

Abstract: A wind turbine blade (162) and a method of forming a wind turbine blade. The method includes: forming an inner segment (10) of an airfoil, leaving a portion (16) of an inner weave (12) extending from the inner segment; forming an outer segment (18) of the airfoil, leaving a portion (24) of an outer weave (20) extending from the outer segment; overlapping the extending portion of the inner weave with the extending portion of the outer weave; infusing the overlapped extending portions with additional resin; and curing the additional resin to form a monolithic airfoil (160).

Abstract: A method and system for improving power production efficiency on a wind farm having of a plurality of spatially distributed wind turbines is provided. The method includes receiving a wind measurement that includes a wind direction impinging on a turbine (20), determining a misalignment of the wind turbine with respect to the wind direction, and activating a wake steering control for the wind turbine (20) to implement the misalignment of the wind turbine (20) with the wind direction such that the misalignment is adapted to steer a wake of the wind turbine away from a neighboring wind turbine (30). A wind turbine arrangement including a nacelle, a yaw controller, and a yaw drive is also provided.

Abstract: A closed mold arrangement for manufacturing a wind turbine blade, including: a closed outer mold (10); a mechanism (44) to selectively flex the outer mold (10) across a range of outer geometries; and a first inner mold (92, 120). The first inner mold (92, 102, 120, 140) is used in the closed outer mold (10) when the closed outer mold (10) is in a first outer geometry and thereby defines a first blade geometry. Alternatively a second inner mold (102, 140) is used in the closed outer mold (10) when the closed outer mold (10) is flexed to a second outer geometry different than the first outer geometry and thereby defines a second blade geometry.