Abstract: The invention provides a fatigue exciter for wind turbine blades. Wind turbine blades require excitation at or near their natural frequency to induce bending moments that simulate in service loadings and must be easily controllable and with the minimum of unnecessary added mass or force. The invention provides a device and a method by which force controlled feedback is used for finding an optimal excitation frequency. This force could be provided e.g. by a digital signal generator.

Abstract: A wind turbine is provided. The wind turbine includes a generator, an output thereof being connectable to a power grid via a power transmission path, the power transmission path comprising a generator side converter coupled to the output of the generator, a grid side converter coupled to the power grid, and a DC link coupled between the generator side converter and the grid side converter. For diverting the generator power, a load dump arrangement is provided which includes at least one resistor, a plurality of switches, and a plurality of electrical connections which electrically connect the at least one resistor to the output of the generator and across the DC link via the plurality of switches. One common and configurable load dump is used for both converter system failures and grid failures. As compared to two separate load dumps for converter failures and grid failures, the single load dump will require a smaller space for a wind turbine.

Abstract: The present invention relates to a high-voltage power converter comprising a number of controllable switching valves, each switching valve comprising a plurality of series connected switching units, the high-voltage power converter further comprising a resonance circuit comprising a link inductor and a link capacitor, and a plurality of clamping circuits connected in series, each clamping circuit comprising a clamping capacitor and a clamping switching unit.

Abstract: The invention relates to a method for moving a wind turbine component, such as a wind turbine hub, from a transportation position to a wind turbine assembly position. The method comprises the steps of: attaching a handling unit to a structural part of the wind turbine component, operatively connecting the handling unit to a wire of a crane system, lifting the wind turbine component with the crane system to an assembly position of the wind turbine, the handling unit and the wind turbine component being suspended from a wire of the crane system, and rotating the wind turbine component with the handling unit during the lifting of the wind turbine component in order to orientate the wind turbine component for assembly. The invention also relates to a handling unit and a wind turbine hub and use hereof.

Abstract: A method of controlling noise emission of a wind park includes monitoring noise emitted from the wind park by detecting and identifying noise emitted by some or all of the plurality of the wind park's wind turbines and estimating the level thereof. If the level of the monitored noise exceeds a predetermined noise threshold the wind park controller commands one or more of the wind turbines, chosen by the importance of its or their relative influence on the noise emitted from the wind park to the measuring location, to change operation to an operation mode with reduced noise emission.

Abstract: A method is disclosed for calibrating a wind turbine sensor placed on a component of a wind turbine and where the wind turbine is of the type having a rotor with at least one pitchable wind turbine blade. The method comprises pitching one or more of the blades according to a predetermined pitch movement and detecting the response signal from the wind turbine sensor at least partly caused by the pitch movement. From this is then determined a characteristic sensor response value which upon comparison to a predetermined sensor calibration parameter forms the basis for a calibration of the wind turbine sensor if needed. The characteristic sensor response value may be determined from the pitch movement having been performed a number of times over a longer period of time. The invention further relates to a control system and a wind turbine configured for performing the method.

Abstract: A wind turbine blade includes one or more electric powered modules powered by light beams so as to provide a galvanic separation between the electric powered modules and a lightning protection system in a wind turbine blade. The modules have a power supply converting an energy source in the form of light beams to electrical power for the one or more modules. A wind turbine and a method for manufacturing a wind turbine blade are also disclosed.