Abstract: A rotor blade with a leading edge and a trailing edge, wherein the rotor blade is designed and configured for being exposed to a fluid flowing substantially from the leading edge to the trailing edge) of the rotor blade, the rotor blade includes at least one sensor for detecting flow characteristics of the fluid, and the rotor blade further includes at least one actuator for producing an anti-noise signal. The sensor and the actuator are both arranged at the surface of the rotor blade, and the actuator is arranged and prepared such that flow-induced edge noise of the rotor blade, which is generated by the fluid, is at least partly cancelled out by the anti-noise signal. The disclosure furthermore relates to a wind turbine including at least one such rotor blade.

Abstract: A rotor blade with a leading edge and a trailing edge, wherein the rotor blade is designed and configured for being exposed to a fluid flowing substantially from the leading edge to the trailing edge) of the rotor blade, the rotor blade includes at least one sensor for detecting flow characteristics of the fluid, and the rotor blade further includes at least one actuator for producing an anti-noise signal. The sensor and the actuator are both arranged at the surface of the rotor blade, and the actuator is arranged and prepared such that flow-induced edge noise of the rotor blade, which is generated by the fluid, is at least partly cancelled out by the anti-noise signal. The disclosure furthermore relates to a wind turbine including at least one such rotor blade.

Abstract: A method for monitoring blade frequencies of a wind turbine and a monitoring system for performing the method are provided. An accelerometer or G-sensor is placed into a nacelle of a wind turbine and thereby measuring the vibrations of the nacelle. To extract the vibration signals originating from each blade, the vibration signals are combined with the measuring signals from the azimuth angle sensor (rotating angle), which is normally used for pitch control. To further extract each blade frequency a Fast Fourier Transformation is used on the modulated G-sensor signals. To further monitor a severe and alarming change in each blade frequency, each blade frequency is compared to the other blade frequencies and an alarm is set when a given level is reached.

Abstract: An asynchronous power generator for a wind turbine is provided. The asynchronous power generator includes a voltage supply and a stator with stator coils supplied with an alternating voltage by the voltage supply. The voltage supply is configured to adjust the voltage supplied to the stator coils based upon an output power generated by the wind turbine. Further, a method of voltage control is provided.

Abstract: One or more bolt gauges each with a built-in load cell are positioned on a blade bolt or a bearing bolt between a pitch bearing and a tightening means and tensioned by the securing means at the inside or the outside of a hub of a wind turbine. The bolt gauge then outputs a signal descending both from the tension from the bolt/securing means connection and the tension from the blade when the blade is vibrated due to wind forces and the rotation of the blade when the hub of the wind turbine is rotating.

Abstract: Wind turbine, yaw system controller and yaw system for a wind turbine and method of reducing the loads on such a yaw system. A method for reducing the loads acting on a wind turbine yaw system (19) due to yawing moments which are induced to the yaw system (19) by a rotor which comprises at least one rotor blade with a pitch control system is provided. In the method, the yawing moment which is induced to the yaw system (19) by the rotor is determined and the pitch of the at least one rotor blade is set based on the detected yawing moment such that the determined yawing moment is reduced.

Abstract: An asynchronous power generator for a wind turbine is provided. The asynchronous power generator includes a voltage supply and a stator with stator coils supplied with an alternating voltage by the voltage supply. The voltage supply is configured to adjust the voltage supplied to the stator coils based upon an output power generated by the wind turbine. Further, a method of voltage control is provided.

Abstract: One or more bolt gauges each with a built-in load cell are positioned on a blade bolt or a bearing bolt between a pitch bearing and a tightening means and tensioned by the securing means at the inside or the outside of a hub of a wind turbine. The bolt gauge then outputs a signal descending both from the tension from the bolt/securing means connection and the tension from the blade when the blade is vibrated due to wind forces and the rotation of the blade when the hub of the wind turbine is rotating.

Abstract: A method for monitoring blade frequencies of a wind turbine and a monitoring system for performing the method are provided. An accelerometer or G-sensor is placed into a nacelle of a wind turbine and thereby measuring the vibrations of the nacelle. To extract the vibration signals originating from each blade, the vibration signals are combined with the measuring signals from the azimuth angle sensor (rotating angle), which is normally used for pitch control. To further extract each blade frequency a Fast Fourier Transformation is used on the modulated G-sensor signals. To further monitor a severe and alarming change in each blade frequency, each blade frequency is compared to the other blade frequencies and an alarm is set when a given level is reached.

Abstract: A method for reducing the loads acting on a wind turbine yaw system due to yawing moments which are induced to the yaw system by a rotor which comprises at least one rotor blade with a pitch control system is provided. In the method, the yawing moment which is induced to the yaw system by the rotor is determined and the pitch of the at least one rotor blade is set based on the detected yawing moment such that the determined yawing moment is reduced.