Abstract: A motion controller for a floating wind turbine including a number of rotor blades is provided. The motion controller is arranged to adjust the blade pitch of each rotor blade when the floating wind turbine is operating in winds below the rated wind speed so as to create a net force that damps a surge motion of the floating wind turbine. Also provided is a method of damping the motion of a floating wind turbine and a wind turbine having such a motion controller.

Abstract: A blade pitch controller for a wind turbine includes a nominal control system and a tower feedback loop. The tower feedback loop includes a filtering system. The filtering system is arranged to control wind turbine blade pitch so as to provide additional effective stiffness to the wind turbine in response to motion of the wind turbine which is above a filter frequency of the filtering system.

Abstract: A wind turbine system including a rotationally asymmetric floating wind turbine installation and a rotationally asymmetric mooring system connected to the floating wind turbine installation. The mooring system includes a number of mooring lines connected, directly or indirectly, to the floating wind turbine installation such that the mooring system has a lower yaw stiffness when a wind acting on the wind turbine installation comes from 0° than when a wind acting on the wind turbine installation comes from ±90°. A wind coming from 0° is defined as a wind direction when the horizontal part of the aerodynamic rotor thrust force resulting from the wind is directed towards the center of gravity of the floating wind turbine installation.

Abstract: A controller is provided for a floating wind turbine including a rotor with a number of rotor blades connected to a generator. The controller includes an active damping controller for calculating one or more outputs for damping both a first motion of the floating wind turbine in a first frequency range and a second motion of the floating wind turbine in a second frequency range based on an input of the first motion and an input of the second motion, The controller is arranged to calculate an output for controlling a blade pitch of one or more of the rotor blades and/or for controlling a torque of the generator based on an actual rotor speed, a target rotor speed, and the one or more outputs from the active damping controller such that both the first motion and the second motion will be damped.

Abstract: A blade pitch controller for a wind turbine includes a nominal control system and a tower feedback loop. The tower feedback loop includes a filtering system. The filtering system is arranged to control wind turbine blade pitch so as to provide additional effective stiffness to the wind turbine in response to motion of the wind turbine which is above a filter frequency of the filtering system.

Abstract: A method of controlling a turbine of a floating wind turbine structure to reduce fatigue of moorings of the floating wind turbine structure includes curtailing the turbine based on a pitching motion of the floating wind turbine structure and on a wind direction at the floating wind turbine structure relative to an orientation of the moorings of the floating wind turbine structure. Optionally, the curtailment may be further based on a degree of displacement of the floating wind turbine structure from a reference location.

Abstract: A method of controlling a turbine of a floating wind turbine structure to reduce fatigue of its moorings comprises curtailing the turbine based on a pitching motion of the wind turbine structure and on a wind direction at the wind turbine structure relative to the orientation of moorings of the wind turbine structure. Optionally, the curtailment may be further based on the degree of displacement of the wind turbine structure from a reference location.

Abstract: A motion controller for a floating wind turbine with a plurality of rotor blades, is arranged to control a motion of the floating wind turbine in a yaw direction. The controller adjusts the blade pitch of each rotor blade so as to create a net force to control the motions. The controller includes a control action which is proportional to a yaw offset angle and/or a control action which is proportional to an integral of the yaw offset angle.

Abstract: A motion controller for a floating wind turbine with a plurality of rotor blades, is arranged to control a motion of the floating wind turbine in a yaw direction. The controller adjusts the blade pitch of each rotor blade so as to create a net force to control the motions. The controller includes a control action which is proportional to a yaw offset angle and/or a control action which is proportional to an integral of the yaw offset angle.