Abstract: A method of damping oscillations in a multi-rotor wind turbine and a wind turbine are provided. The wind turbine comprises a wind turbine support structure and at least a first nacelle with a first rotor and a second nacelle with a second rotor, at least one of the nacelles being located at a position away from a central longitudinal axis of the wind turbine support structure. The method comprises the steps of receiving and processing motion data, selecting a damping algorithm and generating a pitch control signal. The processing comprises determining at least one prominent oscillation mode of the wind turbine support structure and selecting a corresponding damping algorithm.

Abstract: A method and a device for dampening movement in a multiple rotor (MR) wind turbine located at sea and comprising a tower (2) extending in an upwards direction, a load carrying structure (3, 4) forming a first section (3) and a second section (4), the first and second sections extending in different directions away from the tower (2). To provide efficient dampening of the movement, the method comprises tethering a first body (20) to the first section (3), the first body being at least partly submerged into the sea.

Abstract: A first aspect of the invention provides a method of testing a yaw system (200) of a wind turbine, the wind turbine comprising a rotor; the yaw system (200) comprising a yaw gear (202) coupled to the rotor so that rotation of the yaw gear (202) causes yaw rotation of the rotor, and first and second sub-systems (204a, 204b), the first sub-system (204a) comprising a first pinion gear (206a) and a first drive motor (208a) coupled to the yaw gear (202) by the first pinion gear (206a), the second sub-system (204b) comprising a second pinion gear (206b) and a second drive motor (208b) coupled to the yaw gear (202) by the second pinion gear (206b).

Abstract: The present invention relates to a multirotor wind turbine comprising at least two rotor nacelle assemblies mounted to a support arrangement via respective yawing systems, and a toe angle control system for controlling the toe angles of the rotor nacelle assemblies with respect to the support arrangement; wherein the toe angle control system is configured to operate in a first mode in which the rotor nacelle assemblies are held at positive toe angles while the wind turbine is generating power in a main production mode; wherein the toe angle control system is further configured to monitor the operating mode of the wind turbine, and to switch to a second mode in which the yawing systems of the rotor nacelle assemblies are operated to reduce the toe angles of the rotor nacelle assemblies if an operating mode-based trigger condition has been met.

Abstract: Aspects of the present invention relate to a nacelle (14) for a wind turbine generator (10), and a method for transferring components into and out of a wind turbine generator (10). The nacelle (14) comprises a housing (26) surrounding an internal volume (24) of the nacelle (14). The housing (26) has a maintenance opening (50). The nacelle comprises a carriage (54) configured to hold a component (48), the carriage (54) being movable between a first position and a second position to transfer the component (48) through the maintenance opening (50). When the carriage (54) is in the first position, the component (48) is held within the internal volume (24). When the carriage (54) is in the second position, the component (48) is held such that at least a portion of the component (48) is outside the housing (26).

Abstract: A method for controlling a multirotor wind turbine comprising two or more energy generating units is disclosed. At least one load carrying structure is connected to a foundation or to a tower via a yaw arrangement, and the load carrying structure carries the at least two energy generating units. A requirement to a change in operation of at least a first of the energy generating units is detected. Control commands for the first energy generating unit and for at least a second energy generating unit, mounted on the same load carrying structure, are generated. The control commands cause the required change in operation, and the control commands cause coordinated operation of at least the first energy generating unit and the second energy generating unit. The control commands are generated under the constraint that a yaw moment of the yaw arrangement is maintained below a predefined threshold level.

Abstract: According to a first aspect of the invention, there is provided a wind turbine blade having a split blade configuration, comprising a first blade module defining an aerofoil profile and a second blade module defining an aerofoil profile; a damping module intermediate the first blade module and the second blade module; wherein the damping module comprises a first blade interface for joining to the first blade module and a second blade interface for joining to the second blade module. The damping module comprises a vibration damping unit. Beneficially, the invention provides a useful way in which to integrate motion damping functionality into a modular wind turbine blade.

Abstract: A method and a device for dampening movement in a multiple rotor (MR) wind turbine located at sea and comprising a tower (2) extending in an upwards direction, a load carrying structure (3, 4) forming a first section (3) and a second section (4), the first and second sections extending in different directions away from the tower (2). To provide efficient dampening of the movement, the method comprises tethering a first body (20) to the first section (3), the first body being at least partly submerged into the sea.

Abstract: A first aspect of the invention provides a method of monitoring the condition of a yaw system of a wind turbine, the wind turbine comprising a rotor, the yaw system arranged to control a yaw rotation of the rotor, the method comprising: providing design data 5 representing an expected relationship between yaw moment and yaw rotation speed; measuring a pair of parameters, the pair of parameters comprising a yaw moment parameter indicative of a yaw moment applied to the yaw system, and a yaw rotation speed parameter indicative of a yaw rotation speed caused by the yaw moment; using the design data to evaluate whether the pair of parameters deviates from the expected 10 relationship; and determining a condition of the yaw system on the basis of the evaluation.

Abstract: A multirotor wind turbine (1) comprising a yaw arrangement (6) and a tower (2) is disclosed. A load carrying structure comprises first and second arms (3) extending from the yaw arrangement (6) and carrying energy generating units (4). the yaw arrangement (6) comprises an outer wall part (7) arranged coaxially with the tower (2) and forming a closed ring extending circumferentially about an outer surface of the tower (2), thereby forming a space (8) between the tower (2) and the outer wall part (7). The outer wall part (7) and the outer surface of the tower (2) are rotatable relative to each other.

Abstract: A first aspect of the invention provides a method of testing a yaw system (200) of a wind turbine, the wind turbine comprising a rotor; the yaw system (200) comprising a yaw gear (202) coupled to the rotor so that rotation of the yaw gear (202) causes yaw rotation of the rotor, and first and second sub-systems (204a, 204b), the first sub-system (204a) comprising a first pinion gear (206a) and a first drive motor (208a) coupled to the yaw gear (202) by the first pinion gear (206a), the second sub-system (204b) comprising a second pinion gear (206b) and a second drive motor (208b) coupled to the yaw gear (202) by the second pinion gear (206b).

Abstract: A first aspect of the invention provides a method of monitoring the condition of a yaw system of a wind turbine, the wind turbine comprising a rotor, the yaw system arranged to control a yaw rotation of the rotor, the method comprising: providing design data 5 representing an expected relationship between yaw moment and yaw rotation speed; measuring a pair of parameters, the pair of parameters comprising a yaw moment parameter indicative of a yaw moment applied to the yaw system, and a yaw rotation speed parameter indicative of a yaw rotation speed caused by the yaw moment; using the design data to evaluate whether the pair of parameters deviates from the expected 10 relationship; and determining a condition of the yaw system on the basis of the evaluation.

Abstract: A multirotor wind turbine (1) comprising a yaw arrangement (6) and a tower (2) is disclosed. A load carrying structure comprises first and second arms (3) extending from the yaw arrangement (6) and carrying energy generating units (4). the yaw arrange-ment (6) comprises an outer wall part (7) arranged coaxially with the tower (2) and forming a closed ring extending circumferentially about an outer surface of the tower (2), thereby forming a space (8) between the tower (2) and the outer wall part (7). The outer wall part (7) and the outer surface of the tower (2) are rotatable relative to each other.

Abstract: There is presented a method for controlling a rotor on a wind turbine, wherein the rotor is comprising one or more blades, and wherein the wind turbine is comprising a pitch system, the method comprising: Operating the rotor in a standstill or idling operating state, determining or receiving one or more control parameters, where the control parameters enable determining one or more yawing parameters may be described as a function of the one or more control parameters, wherein the one or more yawing parameters comprises one or more of: An angular yawing velocity of the a yawing section, an angular yawing acceleration of the yawing section, and/or a yawing moment applied by the yawing section on a remainder of the wind turbine, and pitching based on the one or more control parameters one or more blades of the rotor with the pitch system.