Abstract: Wind turbines are provided comprising a support structure having a tower and a nacelle mounted on the support structure. A first region (damper region) of the wind turbine including at least a first part of the nacelle is flexibly coupled to a second region (to be damped) of the wind turbine including at least the support structure. Methods are also provided for determining a suitable stiffness of the flexible coupling of the damper region to the region to be damped of any one of said wind turbines. These methods comprise determining a modal mass of the region to be damped depending on a given tower bending mode; and determining the stiffness of the flexible coupling of the damper region to the region to be damped depending on the calculated modal mass of the region to be damped and on the mass of the damper region.

Abstract: A method for determining one or more dynamic properties of a part of a wind turbine comprises the converter sending an input signal to the generator to create an input load, measuring a response from the part under the input load with one or more sensors, and determining one or more dynamic properties of the part from the response and the input load. Also disclosed are methods for determining a fault and for generating a fault register.

Abstract: Floating offshore structures comprising a buoyancy structure arranged such that in use it remains below the sea level, and a tower, wherein the buoyancy structure is attached to the tower by a substantially tubular connecting structure, wherein one or more through channels are provided in the buoyancy structure, the through channels being traversing the buoyancy structure and extending from a bottom portion of the buoyancy structure to an inner portion of the connecting structure, the through channels being dimensioned such that sea water can flow into and out of the connecting structure with variations of the sea level. The application further relates to floating offshore structures comprising a wind turbine and to methods of reducing buoyancy variations in such floating offshore structures.

Abstract: Wind turbines are provided comprising a support structure having a tower and a nacelle mounted on the support structure. A first region (damper region) of the wind turbine including at least a first part of the nacelle is flexibly coupled to a second region (to be damped) of the wind turbine including at least the support structure. Methods are also provided for determining a suitable stiffness of the flexible coupling of the damper region to the region to be damped of any one of said wind turbines. These methods comprise determining a modal mass of the region to be damped depending on a given tower bending mode; and determining the stiffness of the flexible coupling of the damper region to the region to be damped depending on the calculated modal mass of the region to be damped and on the mass of the damper region.