A rotor turning device for balancing a rotor secured atop a tower of a wind turbine during installation and/or repair of one or more rotor blades of the wind turbine includes a hydraulic drive mechanism for operably engaging with a brake disc of the wind turbine. The brake disc is positioned adjacent to a gearbox of the wind turbine. The rotor turning device also includes a mounting device for securing the rotor turning device adjacent to the brake disc of the wind turbine. Thus, when the hydraulic drive mechanism engages the brake disc, the rotor is rotated to a desired position so as to position one or more rotor blades of the wind turbine in a balanced configuration.

A rotor turning device for balancing a rotor secured atop a tower of a wind turbine during installation and/or repair of one or more rotor blades of the wind turbine includes a hydraulic drive mechanism for operably engaging with a brake disc of the wind turbine. The brake disc is positioned adjacent to a gearbox of the wind turbine. The rotor turning device also includes a mounting device for securing the rotor turning device adjacent to the brake disc of the wind turbine. Thus, when the hydraulic drive mechanism engages the brake disc, the rotor is rotated to a desired position so as to position one or more rotor blades of the wind turbine in a balanced configuration.

The invention relates to the use of laser beams for measuring rotors, in particular wind turbines, for determining an imbalance or defining the absolute setting angle and/or measuring a half-profile of a rotor blade, and a method for determining a torsion of the rotor blade as a deviation between two pitch angles. In contrast to the solution in EP 2582970A1, the invention enables the determining of the absolute pitch angle of a rotor blade during operation, without it being necessary to obtain information relating to the rotor blade or reference points with a Known position relative to the pitch axis, in particular using measuring devices that are mobile and/or positioned on the ground. It is also possible to contactlessly detect imbalances.

The present invention relates to a method of correcting rotor imbalance and a wind turbine thereof. The correction method comprises measuring the vibrations within at least one time window and determining an imbalance factor and an imbalance phase. The values of the parameters in the equation for calculating the correction action are then updated based on the imbalance factor and an imbalance phase. A correction angle for each of the wind turbine blades is calculated using these adjusted parameters. The correction angle is used to aerodynamically balance the rotor, and a model may be used to determine the initial values of the parameters. Another imbalance factor and imbalance phase is determined based on another set of measurements. This imbalance factor is then used to calculate a mass moment for correcting the mass imbalance in the wind turbine blades. The weight and location of a balancing mass is finally calculated based on this mass moment and installed in the respective wind turbine blades.

The present invention relates to a method of correcting rotor imbalance and a wind turbine thereof. The correction method comprises measuring the vibrations within at least one time window and determining an imbalance factor and an imbalance phase. The values of the parameters in the equation for calculating the correction action are then updated based on the imbalance factor and an imbalance phase. A correction angle for each of the wind turbine blades is calculated using these adjusted parameters. The correction angle is used to aerodynamically balance the rotor, and a model may be used to determine the initial values of the parameters. Another imbalance factor and imbalance phase is determined based on another set of measurements. This imbalance factor is then used to calculate a mass moment for correcting the mass imbalance in the wind turbine blades. The weight and location of a balancing mass is finally calculated based on this mass moment and installed in the respective wind turbine blades.

A floating offshore horizontal axis wind turbine structure, including an anchored part anchored to a sea bed, and a rotatable part, the structure being supported by at least a pivot buoy, the pivot buoy includes a lower body anchored to the seabed and an upper body fixed to the rotatable part structure; an electrical connection between the lower body and the upper body; and a yaw system connecting the upper body with the lower body. The yaw system includes an inner ring connected to one of the upper and lower body, and an outer ring connected to the other of the upper and lower body; wherein the inner and outer rings are configured to rotate with respect to each other around a vertical yaw axis. The yaw system allows an alignment of the rotatable part with the prevailing wind direction, by rotating about the vertical yaw axis.

A floating offshore horizontal axis wind turbine structure, including an anchored part anchored to a sea bed, and a rotatable part, the structure being supported by at least a pivot buoy, the pivot buoy includes a lower body anchored to the seabed and an upper body fixed to the rotatable part structure; an electrical connection between the lower body and the upper body; and a yaw system connecting the upper body with the lower body. The yaw system includes an inner ring connected to one of the upper and lower body, and an outer ring connected to the other of the upper and lower body; wherein the inner and outer rings are configured to rotate with respect to each other around a vertical yaw axis. The yaw system allows an alignment of the rotatable part with the prevailing wind direction, by rotating about the vertical yaw axis.

A control method for controlling a wind turbine comprising a rotor hub with a shaft and at least two blades, and a nacelle rotatably coupled to the tower through a yaw system, is provided. The control method includes steps for measuring a first periodic variable relating to the nacelle, measuring a second periodic variable relating to the shaft, estimating a yaw moment based on the data obtained from the first variable, processing the signal corresponding to the estimated yaw moment to extract a 1P frequency component from the signal, calibrating the yaw moment estimated, and adjusting the pitch angle of the corresponding blade to counteract the 1P frequency component of the estimated signal of the yaw moment after calibration, in turn comparing it with the signal of the second variable, is also provided.

Techniques for controlling loading on a wind turbine blade in the flap-wise direction. A system model has a description of flap loading on the blade and is used to predict flap loading on the blade over a prediction horizon using the system model. A dynamic flap loading limit is determined based on predicted flap loading and a measured flap loading, and a constraint is defined to limit flap loading on the blade based on the dynamic flap loading limit. The predicted flap loading is used in a cost or performance function, and the cost function is optimized subject to the constraint to determine pitch for the blade to control flap loading on the blade. Advantageously, the dynamic limit varies based on discrepancies between predicted and measured flap loading to allow for adaptive back-off from extreme loads prior to such loads building up or being exceeded.

The diagnostic system for diagnosing a rotor imbalance of a wind turbine based on acceleration data measured on a nacelle of a wind turbine which is supported by a tower includes a measuring device provided with a triaxial vibration sensor suitable for measuring acceleration data corresponding to vibrations occurring on the nacelle. The system also includes a processing system for processing the acceleration data, suitable for determining the rotor imbalance according to the acceleration data measured on at least two axes on the nacelle. The invention also relates to a method for diagnosing the rotor imbalance of a wind turbine.