Structural member for a wind turbine

Abstract

It comprises a body that has an inertial asymmetrical and/or the body is asymmetrical in terms of geometry and/or mass of with respect to a XZ plane passing substantially through the centre of a wind turbine rotor for withstanding asymmetrical loads acting on the wind turbine. The inertia in sections of the structural member body at one side of the XZ plane may be 50% greater than the inertia in sections of the structural member body at another side of the XZ plane. The structural member may connect the wind turbine tower with the wind turbine rotor and may comprise at least two asymmetrical portions defined on both sides of the XZ plane which may be mutually asymmetrical reinforcing elements.

Claims

1. A structural member for use in a wind turbine, that has a tower and a nacelle having a rotor, the structural member comprising a body, wherein the body comprises an asymmetrical weight distribution with respect to a vertical XZ plane passing substantially through the center of the wind turbine rotor and aligned with an axis of rotation of the wind turbine rotor for withstanding asymmetrical loads acting on the wind turbine, the structural member comprising a base portin configured to connect the nacelle with the tower and a vertical portion configured to connect with the wind turbine rotor, the asymmetrical weight distribution relative to the XZ plane being such that inertia of the structural member is asymmetric with respect to the XZ plane.

2. The structural member as claimed in claim 1, wherein the structural member body comprises one or both of an asymmetrical geometry or different materials with respect to the XZ plane that produces the weight distribution.

3. The structural member as claimed in claim 1, wherein the inertia of the structural member body at one side of the XZ plane is substantially 50% greater than the inertia of the structural member body at an oppsite side of the XZ plane.

4. The structural member as claimed in claim 1, wherein the structural member body comprises comprises a reinforcement element at each side of the XZ plane, the reinforcing elements extending between the base portion and the vertical portion and having different configurations that provide the asymmetric weight distribution of the body relative to the XZ plane.

5. The structural member as claimed in claim 4, wherein the vertical portion is configured to connect with an intermediate frame of the wind turbine.

6. The structural member as claimed in claim 4, wherein the vertical portion is configured to connect with a main bearing of the wind turbine.

7. A wind turbine comprising a tower and a nacelle having a rotor, wherein the wind turbine further comprises the structural member as claimed in claim 1 for connecting the tower with the nacelle and connecting the rotor with the nacelle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Particular examples of the present wind turbine structural member will be described in the following by way of a non-limiting example, with reference to the appended drawings, in which:

(2) FIG. 1 is a schematic elevational part view of a wind turbine in which a nacelle, a rotor and a tower top portion are shown;

(3) FIG. 2 is a schematic elevational part view of a direct drive wind turbine;

(4) FIG. 3 is a perspective view of one example the present structural member;

(5) FIG. 3a is a top plan view of the structural member shown in FIG. 3;

(6) FIG. 4 is a perspective view of the structural member shown in FIGS. 3 and 3a, with the structural member partially sectioned by a substantially vertical plane;

(7) FIG. 4a is a rear side view of the structural member shown in FIG. 4;

(8) FIG. 5 is a bottom view of the structural member shown in FIGS. 4 and 4a; and

(9) FIG. 6 is an elevational view of the structural member shown in FIGS. 4, 4a, and 5.

DETAILED DESCRIPTION OF EXAMPLES

(10) One possible example of the present structural member for a wind turbine 200 is disclosed herein and shown in the FIGS. 1-6 of the drawings.

(11) FIG. 1 is a schematic elevational part view of one example of a wind turbine 200 to which the present structural member is applied as a non-limiting example. The wind turbine 200 includes a tower 210 and a nacelle 220 that is rotatably disposed at the top of the tower 210. The nacelle 220 comprises a frame 240 and a rotor 221.

(12) The rotor 221 comprises a plurality of blades 222, such as three, attached a central hub 226 that is rotatably mounted on the nacelle 220. The blades 222 are disposed projecting radially outwardly from the central hub 226 and connected to a rotor shaft 222a. The rotor shaft 222a acts as a low speed shaft and drives a high speed shaft 224 via a gearbox 225 which in turn drives a generator 223 arranged inside the nacelle through the high speed shaft 224. A yaw bearing assembly 230 is disposed between the top of the tower 210 and the frame 240 of the nacelle 220.

(13) The frame 240 is a structure arranged within the nacelle 220 comprising a front frame 243 attached thereto for supporting the rotor 221. The frame 240 can be rotated relative to the tower 210 through the yaw bearing assembly 230. In operation, loads are transferred through the frame 240. The frame 240 can be made of a single part or it can be made of multiple parts, as required. The central hub 226 is connected to the nacelle 220 through the frame 240 such that the central hub 226 is allowed to rotate about an axis. In some cases, the central hub 226 may be supported through a bearing. In any case, the nacelle 220 does not have any structural function and only serves for housing purposes.

(14) In the present example, the structural member is the frame 240 connecting the wind turbine tower 210 with the wind turbine rotor 221. As shown in FIGS. 3-6 of the drawings, the structural member 240 comprises a body that is asymmetrical with respect to a XZ plane passing substantially through the centre of the wind turbine rotor 221. The XZ plane is a substantially vertical plane of symmetry of the rotor 221 but in some cases it may correspond to a plane of symmetry of the nacelle 220 itself The asymmetry of the structural member 240 may be measured inertially or in terms of mass, suitable for withstanding asymmetrical loads acting on the wind turbine 200.

(15) Referring again to FIGS. 3-6 of the drawings, the asymmetrical structural member 240 comprises a base portion 241, a vertical portion 242 and side portions 245, 246. The base portion 241 of the asymmetrical structural member 240 connects the top of the tower 210 with the nacelle 220 while the vertical portion 242 of the asymmetrical structural member 240 connects the nacelle 220 with an intermediate frame of the wind turbine 200 or with the front frame 243 or with the central hub 226 trough the main bearing.

(16) FIG. 4a, which is a rear side view of the structural member 240 clearly shows the asymmetry through the different side portions 245, 246 as sectioned by a substantially vertical plane. As it can be seen, the resulting section on each sideportion 245, 246 is quite different, e.g. about 50%, resulting in the inertial asymmetry of the whole structural member body 240 with respect to the XZ plane.

(17) The side portions 245, 246 of the asymmetrical structural member 240 are on both sides of the XZ plane. The side portions 245, 246 include mutually asymmetrical reinforcing elements as shown in the FIGS. 3-6 of the drawings. The asymmetrical reinforcing elements 245, 246 attach the base portion 241 with the vertical portion 242 of the structural member 240.

(18) The side portions 245, 246 of the asymmetrical structural member 240 are different, asymmetric, in terms of shapes and/or in terms of mass distribution. For example, one side portion 245 may be almost 10% lighter than the other side portion 246. This results in redistributed loads to the yaw bearing 230 which in turn results in 20% reduction of maximum loads in the rolling elements.

(19) The design of asymmetrical side portions 245, 246 on both sides of the XZ plane in the present structural member 240 is a topological optimization of wind turbine structural parts dispensing with unnecessary symmetry used so far.

(20) Although only a number of particular examples and examples of the wind turbine structural member have been disclosed herein, it will be understood by those skilled in the art that other alternative examples and/or uses thereof and obvious modifications and equivalents thereof are possible.

(21) The present disclosure covers all possible combinations of the particular examples described. Reference signs related to drawings and placed in parentheses in a claim, are solely for attempting to increase the intelligibility of the claim, and shall not be construed as limiting the scope of the claim. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow.