US-12624678-B2 - Damping assembly for wind turbines

Abstract

A wind turbine hub assembly including: a plurality of radially arranged blade attachment members for attaching blades with a radially outer blade section with a leading edge and trailing edge wherein each blade extends outwardly from and about a central axis of rotation; a central hub assembly configured to rotate about the axis of rotation with the plurality of blade attachment members being radially arranged and hingedly connected relative to the central hub assembly by respective hinge arrangements to allow relative movement of the blade attachment members relative to the central hub assembly; one or more biasing structures operatively coupled with each blade attachment member wherein a first end of said each biasing structure is attached to the central hub assembly and a second end of the biasing structure is attached to a respective blade attachment member for applying a biasing force.

Inventors

• Rolf Hoffmann

Assignees

• Windsun Pte Ltd

Dates

Publication Date

20260512

Application Date

20221021

Priority Date

20211022

Claims (19)

1. 1 . A wind turbine hub assembly, comprising: a plurality of radially arranged blade attachment members for attaching blades having a radially outer blade section with a leading edge and a trailing edge, wherein each blade extends outwardly from and about a central axis of rotation; a central hub assembly configured to rotate about the axis of rotation, with the plurality of blade attachment members radially arranged and hingedly connected to the central hub assembly by respective hinge arrangements to allow movement of the blade attachment members relative to the central hub assembly; and one or more biasing structures operatively coupled with each blade attachment member, wherein a first end of each said biasing structure is attached to the central hub assembly and a second end of each said biasing structure is attached to a respective one of the blade attachment members, for applying a biasing force, during use, to extend the blade attachment member and an outer section of each blade to a neutral pitched position, whereby the biasing structure resists the movement of the blade attachment member and an outer section of each blade to a coned position during use, wherein each said biasing structure comprises a damping assembly comprising a sealed, fluid-filled cylinder configured to apply the biasing force on a piston rod and extend the piston rod in the neutral pitched position.
2. 2 . The wind turbine hub assembly in accordance with claim 1 , wherein the central hub assembly comprises a central plate, with the plurality of the blade attachment members radially arranged and hingedly connected to the central plate at respective connecting locations by the respective hinge arrangements, allowing movement of the blade attachment members relative to the central plate.
3. 3 . Wind turbine hub assembly in accordance with claim 2 , wherein the central hub assembly further comprises a shaft receiving member spaced away from the central plate along the axis of rotation, the first end of each said biasing structure being attached to the shaft receiving member.
4. 4 . The wind turbine hub assembly in accordance with claim 1 , wherein each said biasing structure is movable between: an extended configuration to apply the biasing force to maintain the blades and the blade attachment members in the neutral pitched position; and a retracted configuration when the forces applied by wind overcome the biasing force of each said biasing structure.
5. 5 . The wind turbine hub assembly in accordance with claim 4 , wherein, in the extended position, the central plate substantially lies in the same plane as the blade attachment members.
6. 6 . The wind turbine hub assembly in accordance with claim 3 , wherein the first end of each said biasing structures is attached to the central hub assembly by a first swivel joint mechanism.
7. 7 . The wind turbine hub assembly in accordance with claim 6 , wherein the first end of each said biasing structures is attached to a portion of said shaft receiving member by the first swivel joint mechanism.
8. 8 . The wind turbine hub assembly in accordance with claim 1 , wherein the second end of each said biasing structures is attached to a radially inner end portion of a respective blade attachment member by a second swivel joint mechanism.
9. 9 . The wind turbine hub assembly in accordance with claim 8 , wherein the second end of each said biasing structures is attached to an attachment arm extending radially inward from the inner end portion of the respective blade attachment member.
10. 10 . The wind turbine hub assembly in accordance with claim 9 , wherein each blade attachment member is hingedly connected to the central plate by one or more spaced apart hinge members, with the attachment arm extending transversely relative to a hinge axis defined by the hinge members.
11. 11 . The wind turbine hub assembly in accordance with claim 9 , wherein, in the neutral position, the second end of each said biasing structure is offset from the hinge axis by its attachment to the attachment arm.
12. 12 . The wind turbine hub assembly in accordance with claim 10 , wherein the hinge axis for each blade attachment members extends transversely across the plane of the attached blade, and wherein the hinge axes of the blade attachment members are non-parallel to each other.
13. 13 . The wind turbine hub assembly in accordance with claim 2 , wherein the second end of each said biasing structures moves away from the central plate as the attached blade attachment member moves towards the coned position, thereby increasing the inclination angle of each said the biasing structure relative to the central plate.
14. 14 . The wind turbine hub assembly in accordance with claim 1 , wherein the first end of each said biasing structure is located at or near an end of the cylinder, and the second end is located at or near an end of the piston rod.
15. 15 . A wind turbine assembly comprising: a plurality of blade assemblies, each blade assembly comprising a blade with a radially outer blade section having a leading edge and a trailing edge, wherein each blade extends outwardly from and about an axis of rotation; a central hub connected to a radially inner portion of each blade assembly, the central hub being configured to rotate about the axis of rotation; wherein the radially inner portion of each blade assembly is hingedly connected to the radially outer blade section by a hinge arrangement, allowing relative movement of the radially outer section about a hinge axis; and a biasing structure operatively coupled with each blade, wherein a first part of the biasing structure is attached to the central hub and a second part is attached to the outer section of each blade, for applying a biasing force to extend the outer section to a neutral pitched position, and whereby the biasing force applied by the biasing structure resists movement of the outer section of each blade to a coned position during use, wherein said biasing structure comprises a damping assembly comprising a sealed, fluid-filled cylinder configured to apply the biasing force on a piston rod and extend the piston rod in the neutral pitched position.
16. 16 . The wind turbine assembly in accordance with claim 15 , wherein the biasing structure applies the biasing force such that, in the neutral pitched position, an angle between the hub's plane of rotation and the leading edge of each blade is less than ten degrees.
17. 17 . The wind turbine assembly in accordance with claim 15 , wherein the biasing structure allows movement of the outer blade section to the coned position when forces from wind overcome the resistive force, such that an angle between the hub's plane of rotation and the leading edge of each blade in the coned position is greater than thirty degrees and less than ninety degrees.
18. 18 . The wind turbine assembly in accordance with claim 15 , wherein the biasing structure is movable between: an extended configuration to apply the biasing force to maintain the blades in the neutral pitched position; and a retracted configuration when forces applied by wind overcome the biasing force.
19. 19 . The wind turbine assembly in accordance with claim 18 , wherein, in the retracted configuration, the angle between the hub's plane of rotation and the leading edge of each blade in the coned position is greater than thirty degrees less than ninety degrees.

Description

TECHNICAL FIELD The present invention relates to an improved damping assembly for use with wind turbines. BACKGROUND Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge. Wind turbines operate by using the kinetic energy of the wind, which is then converted to rotational energy by the blades of the turbine which subsequently spins a generator that converts the rotational energy into electrical energy. There is a need in the field of small wind turbines (5-50 kW), especially in areas with strong winds, to use a passive safety system against overload of the electrical and mechanical components to prevent their destruction. In this patent application a technical solution is described, which works based on a horizontal wind turbine with “down-wind” construction. The wind turbine blades have a flexible suspension at the hub, so that the rotor blades can fold together and unfold again depending on the wind force. A central spring element controls the distribution of forces via a linkage that is directly connected to the blades. The permitted pitch of the blades is determined by two physical variables which are (1) the angle of inclination between the rotor axis and the wing axis and (2) the angle of attack (the so-called pitch). The three blades are controlled synchronously via the linkage and the central spring strut. Due to this synchronicity, a gust of wind cannot cause any damage to the electronics (due to overvoltage) or the mechanics. The aim is to ensure smooth running of the turbine through strong wind phases without having to shut down the turbine. The flexible diameter of the turbine (1) and the pitch adjustment of the blades (2) are responsible for the power at the main shaft and are controlled solely by the wind pressure on the three blades. The strut provides the counterforce on the wing and keeps the system in balance. U.S. Pat. No. 5,226,805 describes such a mechanism, in which the blades of a wind turbine change their pitch and tilt in response to wind speed and load. The goal is to allow a turbine to run through a high wind phase at full rated power without interruption. Other systems only have protection against short gusts and set up for stop and go operation during high wind phases. It is therefore necessary to provide an improved damping system (passive control) that allows small wind turbines to operate continuously and generate power even in sustained strong winds above rated power or in stronger gusts without damaging the rotor, generator, or other parts of the wind turbine. SUMMARY In one aspect, the invention provides a wind turbine hub assembly comprising: a plurality of radially arranged blade attachment members for attaching blades with a radially outer blade section with a leading edge and trailing edge wherein each blade extends outwardly from and about a central axis of rotation;a central hub assembly configured to rotate about the axis of rotation with the plurality of blade attachment members being radially arranged and hingedly connected relative to the central hub assembly by respective hinge arrangements to allow movement of the blade attachment members relative to the central hub assembly;one or more biasing structures operatively coupled with each blade attachment member wherein a first end of each said one or more biasing structures is attached to the central hub assembly and a second end of the one or more biasing structures is attached to a respective blade attachment member for applying a biasing force, during use, to extend the blade attachment member and an outer section of each blade attached to said blade attachment members to a neutral pitched position and whereby the biasing force applied by the biasing structure resists the movement of the blade attachment member and an outer section of each blade to a coned position during use. In an embodiment, the central hub assembly comprises a central plate with the plurality of the blade attachment members being radially arranged and hingedly connected to the central plate at a connecting location by the respective hinge arrangements to allow movement of the blade attachment members relative to the central plate. In an embodiment, the central hub assembly further comprises a shaft receiving member that is spaced away from the central plate along a direction of the axis of rotation, the first part of each biasing structure being attached to said shaft receiving member. In an embodiment, the biasing structure is movable between: an extended configuration to apply the biasing force to maintain the blades and the blade attachment members in the neutral pitched position; anda retracted configuration when the biasing force applied by the biasing structure is overcome by forces applied on the blades and blade attachment members by wind. In an embodiment, in the extended position, the central pl