TOWING OF A FLOATING WIND TURBINE

Abstract

A control system for stabilizing a floating wind turbine is connected to at least one sensor and at least one actuator of the floating wind turbine and configured for: determining a difference between the floater orientation and a predefined desired floater orientation of the floating wind turbine during towing of the floating wind turbine, actuating the at least one actuator during towing of the floating wind turbine for changing the floater orientation of the wind turbine to minimize the difference.

Claims

1-13. (canceled)

14. A floating wind turbine comprising: at least one sensor for measuring at least one parameter associated with a floater orientation of the floating wind turbine, wherein the floater orientation comprises a floater roll angle, a floater pitch angle, and/or a floater yaw angle, at least one actuator actuatable for changing the floater orientation of the floating wind turbine, and a control system connected to the at least one sensor and the at least one actuator and configured for, during towing of the floating wind turbine: receiving the at least one parameter determining the floater orientation of the wind floating wind turbine, determining a difference between the floater orientation and a predefined desired floater orientation of the floating wind turbine, and actuating the at least one actuator for changing the floater orientation of the wind turbine to minimize the difference.

15. The floating wind turbine according to claim 14, further comprising a source of electrical energy for powering, during towing of the floating wind turbine, the at least one sensor, the at least one actuator and the control system, and/or wherein the floating wind turbine is configured to be operated to produce electrical energy during towing of the floating wind turbine.

16. The floating wind turbine according to claim 14, wherein the difference between the floater orientation and the predefined desired floater orientation of the floating wind turbine includes an offset and/or an oscillation, further wherein the difference is in the range of −10° to +10°.

17. The floating wind turbine according to claim 14, wherein the at least one sensor is mounted on a nacelle and/or a blade and/or a tower and/or a floating foundation, wherein the at least one sensor comprises at least one of the group consisting of a spinner pressure sensor, a wind speed sensor, a wind direction sensor, a blade load sensor, and/or wherein the at least one sensor comprises an accelerometer or an inclination sensor or a wave radar.

18. The floating wind turbine according to claim 14, wherein the at least one actuator comprises an electric generator of the floating wind turbine, a blade pitch system, and/or an adjustable spoiler on a nacelle, an active blade add-on, and/or a vortex induced vibration brake.

19. The floating wind turbine according to claim 18, wherein the electric generator is configured to be controllable such that the electric generator can provide an up-righting moment in floater roll, by providing an angular acceleration of the electric generator, further, if the floating turbine is tilting sideways in one direction the electric generator rotates with an angular acceleration in an opposite direction such that a counter moment is generated.

20. The floating wind turbine according to claim 14, wherein the at least one actuator e comprises an adjustable damper configured for damping a vibration of the floating wind turbine, and/or a mass damper.

21. The floating wind turbine according to claim 14, wherein the at least one actuator comprises a liquid damper.

22. The floating wind turbine according to claim 21, wherein the liquid damper comprises a container configured to be filled or emptied out dependent on the needed damping, wherein the liquid damper is fixed to a floating foundation of the floating wind turbine and is configured to work with seawater.

23. A method for controlling an orientation of a floating wind turbine during towing, the method comprising: determining a floater orientation of the wind floating wind turbine, determining a difference between the floater orientation and a predefined desired floater orientation of the floating wind turbine during towing of the floating wind turbine, and actuating the at least one actuator during towing of the floating wind turbine for changing the floater orientation of the wind turbine to minimize the difference.

24. The method according to claim 23, further comprising the step of operating the floating wind turbine during towing the floating wind turbine to produce electrical energy.

25. The method according to claim 23, wherein the floating wind turbine comprises a source of electrical energy, and the method further comprises powering, during towing of the floating wind turbine, the at least one sensor, the at least one actuator and a control system.

26. The method according to claim 23, wherein the at least one actuator comprises a blade pitch system, and the method further comprises utilizing the blade pitch system such that small perturbations are introduced in blade pitch angles for increasing or decreasing a drag on the blades and for making small perturbations to a mass balance of the floating wind turbine.

27. The method according to claim 23, wherein the at least one actuator comprises an adjustable damper configured for damping a vibration of the floating wind turbine and/or a liquid damper and/or a mass damper, the method further comprising: damping of the vibration, an oscillating motion of a floater pitch angle and/or a floater yaw angle and/or a floater roll angle of the floating wind turbine, and/or filling in or emptying out a container of the liquid damper dependent on a needed damping.

28. The method according to claim 23, wherein the at least one actuator comprises an electric generator of the floating wind turbine, and the method further comprises controlling the electric generator such that the electric generator provides an up-righting moment in floater roll, by providing an angular acceleration of the electric generator, further, if the floating turbine is tilting sideways in one direction the electric generator rotates with an angular acceleration in an opposite direction such that a counter moment is generated.

Description

BRIEF DESCRIPTION

[0058] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0059] FIG. 1 shows a floating wind turbine according to an exemplary embodiment of the present invention during towing;

[0060] FIG. 2 shows a more detailed view of the floating wind turbine of FIG. 1 in a first towing configuration; and

[0061] FIG. 3 shows a more detailed view of the floating wind turbine of FIG. 1 in a second towing configuration.

DETAILED DESCRIPTION

[0062] The illustration in the drawings is schematic. It is noted that in different figures, similar or identical elements or features are provided with the same reference signs. In order to avoid unnecessary repetitions elements or features which have already been elucidated with respect to a previously described embodiment are not elucidated again at a later position of the description.

[0063] FIG. 1 shows a floating wind turbine 100 according to an exemplary embodiment of the present invention. The floating wind turbine 100 comprises three blades 140 mounted to a nacelle 160, a tower 130 and a floating foundation 120. The floating wind turbine 100 includes an electrical generator 150 inside the nacelle 160 for transforming the rotational energy of the three blades 140 into electrical energy. The floating wind turbine 100 is towed by a towing vessel 200.

[0064] FIGS. 2 and 3 show in more detail the floating wind turbine 100.

[0065] The floating wind turbine 100 has six individual degrees of freedom in which the floating wind turbine 100 may move. Namely, three translations, i.e. a surge 103, a sway 102 and a heave 101, and three rotation angles, i.e. a floater roll 106, a floater pitch 105 and a floater yaw 104. Furthermore, the floating wind turbine 100 is stabilized by a control system 170 mounted on the floating foundation 120. According to other embodiments of the present invention (not shown), the control system 170 may be mounted on another component of the floating wind turbine 100, for example the nacelle 160 or the tower 130. The alignment of the floating wind turbine 100 as shown in FIG. 2 may illustrate a predefined desired floater orientation of the floating wind turbine 100. The predefined desired floater orientation may be defined by one or more angle values, for example one value of the floater roll 106 and/or a value of the floater pitch 105 and/or a value of the floater yaw 104. Consequently, the predefined desired floater orientation of the floating wind turbine 100 may be defined by a set of predefined desired floater roll 106, floater pitch 105 and floater yaw 104.

[0066] According to the configuration of FIG. 3, the floating wind turbine 100 is tilted around the floater pitch 105 axis such that a difference 231 to a predetermined desired floater pitch angle occurs. The difference 231 may comprise an offset and/or an oscillation. Additionally, the floating wind turbine 100 may tilted around the floater yaw 104 axis such that a difference to the predetermined desired floater yaw angle occurs. Additionally, the floating wind turbine 100 may tilted around the floater roll 106 axis such that a difference to the predetermined desired floater roll angle occurs. The floating wind turbine 100 is tilted by the difference 231 due to external forces due to an incoming wind field 111 acting on the three blades 140 of the floating wind turbine 100 or due to other external forces, for example tidal forces or ocean current forces.

[0067] A weight of the nacelle 160 together with the external forces composes a weight force 134, as shown in FIG. 3. The weight force 234 comprises a first force component 232 and a second force component 233. The first force component 232 is parallel to an extension direction of the tower 230 and the second force component 233 is perpendicular to the first force component 232.

[0068] The difference 231 may detected through a blade load sensor 271, a wind speed sensor 272 and a wind direction sensor 273 each mounted to one of the blades 140 or the nacelle 160.

[0069] Alternatively or additionally, the difference 231 may detected through an accelerometer and/or an inclination sensor and/or a wave radar mounted on any of the nacelle 160 and/or the blade 140 and/or the tower 130 and/or the floating foundation 120. The sensors 271, 272, 273 measure respective parameters, which can be associated with the floater orientation of the floating wind turbine 100. For example, the measure parameters may be associate with a floater roll 106 and/or a floater pitch 105 and/or a floater yaw 104.

[0070] The control system 170 is connected to the sensors 271, 272, 273 which may be present on the floating wind turbine 100 and, during towing of the floating wind turbine 100, receives the parameters measured by the sensors 271, 272, 273 and determines the floater orientation of the floating wind turbine 100. The control system 170 further determines the difference 231 from a predefined desired floater orientation of the floating wind turbine 100. The control system 170 actuates one or more actuator 150, 283 for changing the floater orientation of the wind turbine to minimize said difference 231.

[0071] As actuation device the electric generator 150 of the floating wind turbine 100 may be used. Alternatively or additionally, the blade pitch system (not represented in the figures) may be used as actuation device. Other actuation devices may include an adjustable spoiler on a nacelle and/or an active blade add-on. Further or alternative actuation devices may include an adjustable damper configured for damping a vibration of the floating wind turbine 100.

[0072] As shown in FIG. 3, the actuation device may comprise a liquid damper 283 inside the floating foundation 120.

[0073] According to respective embodiments of the present invention, the difference may be in the range of −10° to +10°, particularly −5° to +5°, more particularly −2° to +2°. This means that the control system 170 may actuate the actuators 150, 283 when the difference 231 reaches a given threshold of ±10°, ±5°, ±2°, respectively. According to an embodiment of the present invention, the control system 170 may actuate the actuators 150, 283 each time a difference 231 greater than 0° is detected, in order to keep such difference at 0°.

[0074] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0075] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.