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.

A system and method are provided for reducing vibrations and loads in one or more rotor blades on a rotor hub of a wind turbine when the rotor hub is in a locked or idling condition. An electronically tunable mass damper is attached to a fixed location on one or more of the rotor blades. The mass damper is maintained on the rotor blades during the locked or idling condition of the rotor hub. The method includes sensing movement of a mass component of the mass damper from vibrations or oscillations induced in the rotor blade. The mass damper is automatically tuned based on the sensed movements of the mass component by automatically varying an electrical characteristic of the mass damper.

A radiating component of the wind turbine is modelled as a plurality of elements, wherein each element represents a physical portion of the radiating component and at least a portion of each of the elements are acoustically coupled to one or more of the other elements. A simulation of a vibrational source located within the wind turbine is applied at an interface of the modelled radiating component. A transfer function is used to determine the transmission of vibrations from an interface with the vibrational source to the elements. Tonal noise radiated from the elements to an environment external to the wind turbine is determined based upon the transmission of vibrations from the interface through the elements. The design of the radiating component, or of a component between the radiating component and the vibrational source, is modified to reduce the tonal noise radiated from the radiating component.

The present invention relates to a damper unit for damping oscillations of a tower structure when secured thereto, the damper unit comprising a damper unit structure adapted for attachment to the tower structure, a pendulum structure, a suspension arrangement for suspending the pendulum structure from the damper unit structure such that the pendulum structure is allowed to displace from a neutral position for the pendulum structure, the suspension arrangement comprising one or more wires for suspending the pendulum structure, a sensor adapted for measuring oscillations of the tower structure, and tuning means configured for adjusting the natural frequency of the suspended pendulum structure in response to measured oscillations of the tower structure. The present invention further relates to an associated method.

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.

A damper position-limiting device is provided, which is mounted in a tower to limit the swing amplitude of a damper installed in the tower. The damper position-limiting device includes at least one web and a position-limiting ring. The web is provided with a mounting hole and at least one stress relief hole. A first side wall of the web has a first specified length along a circumferential direction of the inner wall of the tower, and is connected to the inner wall of the tower. The position-limiting ring is positioned within the mounting hole and connected to the mounting hole and is configured to accommodate an impacting plate of the damper.

A device for damping vibrations in a structure including a first (or inner) element rotatably mounted around a rotational axis and a second (or outer) element rotatably mounted around said rotational axis. A radius (R1) of a circle portion delimitating the first element with respect to the rotational axis, being smaller than a radius (r2) of a circle portion delimitating the second element with respect to the rotational axis.

A damper includes a vibration energy buffering transfer unit and a vibration energy dissipation unit. The vibration energy buffering transfer unit includes a plurality of piston transfer structures and connecting tubes, the piston transfer structures includes a cylinder and a piston arranged as a pair, the plurality of piston transfer structures surrounding the vibration energy dissipation unit, the connecting tubes inter-connecting the plurality of cylinders, the vibration energy dissipation unit includes a damping liquid accommodating cavity and damping liquid accommodated in the damping solution accommodating cavity, and one end of the cylinder or the piston being connected to the damping fluid accommodating cavity. The load-bearing enclosing structure provided with said damper can effectively suppress vibration.

The system and method described herein provide grid-forming control of a power generating asset having a generator, such as a double-fed generator, connected to a power grid. Accordingly, a stator-frequency error is determined for the generator. The components of the stator frequency error are identified as a damping component corresponding to a tower damping frequency and a stator component. Based on the stator component, a power output requirement for the generator is determined. This power output requirement is combined with the damping power command to develop a consolidated power requirement for the generator. Based on the consolidated power requirement, at least one control command for the generator is determined and an operating state of the generator is altered.

A wind turbine noise suppression system can include a sound absorbing batting and a fabric sheet within a column of the wind turbine. The sheet can hang within the column whereas the batting can be placed in at least a bottom and top region. A vibration isolation pad at the top of the column can mitigate a megaphone effect. The pad can be combined with an isolation washer. The pad can be less than a half inch thick, whereas the isolation washer can be less than a quarter inch thick. A sound curtain can be installed at a base of the column to suppress bell resonance. The system can, for example, reduce wind turbine noise up to ninety percent.