Abstract: A method for controlling a pitch angle of blades of a wind turbine rotor during an emergency stop process of the rotor from an operating state, includes the steps of: (i) continuously determining a measure of an angular acceleration of the rotor, (ii) initiating pitching of the rotor blades and continuing pitching until a time (t2) where the determined angular acceleration of the rotor is substantially zero, and (iii) resuming pitching of the rotor blades at the end of a predetermined time period (t3-t2) after the time (t2) where the determined angular acceleration of the rotor was substantially zero. A wind turbine including an emergency stop control system having a mechanism for controlling an emergency stop process of the wind turbine rotor according to such a method is also contemplated.

Abstract: A wind turbine includes a tower, a nacelle located adjacent a top of the tower, a rotor coupled to the nacelle, and a dynamic vibration damper coupled to the tower and configured to dampen vibrations induced in the tower in a torsional direction while negligibly effecting vibrations induced in the tower in bending directions. The dynamic vibration damper may be tuned to a resonant frequency of the wind turbine in the torsional direction. A method of retrofitting a wind turbine with a vibration damper is also disclosed.

Abstract: A wind turbine is presented where the operation lifetime of the main bearing is extended by relieving the main bearing by reducing the mean bending moment on the bearing by means of individual pitch control of the blades of the rotor so as to create an aerodynamic mean tilt moment on the rotor by means of aerodynamic forces on the blades, the tilt moment at least partly counteracting the bending moment caused by the overhang load forces on the main bearing from the gravitational pull on the rotor mass.

Abstract: A wind turbine includes a tower, a nacelle located adjacent a top of the tower, a rotor coupled to the nacelle, and a dynamic vibration damper coupled to the tower and configured to dampen vibrations induced in the tower in a torsional direction while negligibly effecting vibrations induced in the tower in bending directions. The dynamic vibration damper may be tuned to a resonant frequency of the wind turbine in the torsional direction. A method of retrofitting a wind turbine with a vibration damper is also disclosed.

Abstract: A method of operating a pitch controlled wind turbine connected to the utility grid in response to an increase in wind velocity to above a predefined value. The method includes the sequential steps of: reducing the generated power, allowing an intermediate increase in the generator speed, and reducing the generator speed by pitching the wind turbine rotor blades. A wind turbine and a cluster of wind turbines is also contemplated.

Abstract: A method for controlling a pitch angle of blades of a wind turbine rotor during an emergency stop process of the rotor from an operating state, includes the steps of: (i) continuously determining a measure of an angular acceleration of the rotor, (ii) initiating pitching of the rotor blades and continuing pitching until a time (t2) where the determined angular acceleration of the rotor is substantially zero, and (iii) resuming pitching of the rotor blades at the end of a predetermined time period (t3-t2) after the time (t2) where the determined angular acceleration of the rotor was substantially zero. A wind turbine including an emergency stop control system having a mechanism for controlling an emergency stop process of the wind turbine rotor according to such a method is also contemplated.

Abstract: A method of operating a pitch controlled wind turbine connected to the utility grid in response to an increase in wind velocity to above a predefined value. The method includes the sequential steps of: reducing the generated power, allowing an intermediate increase in the generator speed, and reducing the generator speed by pitching the wind turbine rotor blades. A wind turbine and a cluster of wind turbines is also contemplated.

Abstract: A wind turbine is presented where the operation lifetime of the main bearing is extended by relieving the main bearing by reducing the mean bending moment on the bearing by means of individual pitch control of the blades of the rotor so as to create an aerodynamic mean tilt moment on the rotor by means of aerodynamic forces on the blades, the tilt moment at least partly counteracting the bending moment caused by the overhang load forces on the main bearing from the gravitational pull on the rotor mass.