Support structure for a generator of a wind turbine

Abstract

A support structure (50) for a stator of a generator (11), in particular of a wind turbine (1), is described, wherein the support structure comprises a carrier element extending in an axial direction, wherein the carrier element (200) comprises a base section (201), a side section (202) and a top section (203), and wherein the base section (201) of at least one carrier element (200) of the plurality of carrier elements (200) is connected to the base section (201) of another carrier element (200) of the plurality of carrier elements (200). A plurality of circumferential connection elements (205) protruding circumferentially from the base section (201) of one carrier element (200) are connected to a further plurality of connection elements (205) protruding circumferentially from the base section (201) of another carrier element (200) in order to provide a connection between the one carrier element (200) and the other carrier element (200), a plurality of cooling slots (206) being formed between the connection elements (205) for a passage of cooling air.

Description

Technical Field

[0001] The present invention relates to a support structure for a generator of a wind turbine and a generator of a wind turbine comprising such a support structure. In particular, but not exclusively, the support structure may be a segmented support structure. Background Art

[0002] Wind turbines typically include multiple blades for generating mechanical rotational energy. A generator within the wind turbine is configured to generate electrical power when the blades are rotated by the wind. Therefore, wind turbines are designed to efficiently convert wind energy into rotational motion, thereby providing sufficient rotational energy for the generator to generate electrical power.

[0003] The generator of a wind turbine comprises a stator and a rotor.

[0004] The stator generally includes a frame body extending longitudinally along a longitudinal axis and including a plurality of teeth protruding radially from a stator yoke. A plurality of slots are also defined in the stator, each slot being circumferentially bounded by two adjacent teeth. Each slot houses a corresponding winding. The laminations are attached one after the other in the axial direction of the stator and form a lamination stack of the stator, where coils for generating electrical power are arranged. The rotor includes a plurality of magnets. When these magnets rotate, rotational energy is converted into electrical power.

[0005] There are designs in which the rotor is arranged radially outward relative to the stator. In various designs, the stator is arranged radially outward relative to the rotor.

[0006] The segmented lamination stack of the stator needs to be placed at a specified distance from the magnets of the rotor.To do this, a support structure is incorporated in the stator between the stator's lamination segments and the rotor.

[0007] Such a support structure needs to provide multiple functions to prevent collisions between the stator and rotor, particularly in relation to the significant radial and tangential electromagnetic (EM) forces generated within the active generator. Furthermore, it should prevent the occurrence of coincident characteristic frequencies of the segmented assembly and EM excitation force frequencies. Furthermore, the support structure needs to withstand all generator load conditions over a long period of time, i.e., preferably throughout the lifetime of the generator, and should enable efficient cooling by directing cooling air.

[0008] Support structures as part of stators are known in the prior art. These support structures can include carrier elements. These carrier elements are used to couple support structure segments, and thus the support structure as a whole, to the stator lamination segments. T-profile carrier elements are known from the prior art for such support structures. These carrier elements have a base section with a solid vertical element positioned in the center. Alternatively, a mesh plate—a welded plate with openings—can be used.

[0009] Due to the limited surface area of ​​the central element, the coupling of the support structure to the laminated segments of the stator may result in a limited stability connection. Such a connection may not be sufficient to meet the stability requirements of modern wind turbines.

[0010] Furthermore, conventional support structures can still be improved with respect to radial stiffness. For example, it may be desirable to provide a desired level of radial stiffness with less material or in a simpler design. Summary of the Invention

[0011] One object of the present invention may be to provide a support structure for a stator, in particular for a generator of a wind turbine, which meets the requirements regarding mechanical stability and at the same time can be manufactured in a cost-effective manner.

[0012] This object is solved by a support structure segment, a stator and a method for producing the stator according to the subject matter of the invention.

[0013] One aspect of the present invention relates to a support structure for a stator of a generator, in particular a wind turbine, wherein the support structure extends along a longitudinal axis and comprises a plurality of carrier elements, each carrier element comprising a base segment, a side segment, and a top segment. The base segment and the side segments are oriented relative to each other at an external angle (φ) in the range of 70° to 130°. The side segments and the top segment are oriented relative to each other at an internal angle (θ) in the range of 70° to 130°. The base segment is connected to the side segments. The side segments are connected to the top segment. The base segment is spaced apart from the top segment substantially in a radial direction orthogonal to the longitudinal axis. The base segment of at least one of the plurality of carrier elements is connected to the base segment of another of the plurality of carrier elements, a plurality of circumferential connecting elements circumferentially protruding from the base segment of one carrier element are connected to another plurality of connecting elements circumferentially protruding from the base segment of another carrier element 200, so as to provide a connection between the one carrier element and the other carrier element, and a plurality of cooling slots are formed between the connecting elements for cooling air to pass through.

[0014] The present invention provides high radial stiffness. At the same time, it requires less pre-machining of the support elements compared to the prior art. Furthermore, fewer circumferential ribs and less welding are required, thereby reducing material and labor costs. Fewer tangential ribs reduce pressure drop, potentially leading to better cooling. The carrier element not only allows for stable connection of the support structure segments to the laminated structure, but also allows for circumferential connections to other circumferentially adjacent carrier elements.

[0015] The base section, the side sections and the top section of the carrier element describe, for example, a Z-shaped profile. More preferably, in an exemplary embodiment as further described below, the base section, the side sections, the top section, the further side section and the further base section of the carrier element describe an Ω-shaped profile (omega-shaped profile).

[0016] Thereby, the carrier element or the plurality of carrier elements form a support structure segment.One or more laminations of the stator can be coupled to the support structure segment and thus the support structure as a whole forms a lamination section of the stator.

[0017] The support structure segment is preferably used with a generator design in which the stator is arranged radially outward relative to the rotor, but is not limited thereto. The support structure segment can also be used in a generator design with a rotor arranged radially outward relative to the stator.

[0018] According to an embodiment of the present invention, the outer angle φ may be in the range of about 85° to about 120°, and more specifically, in the range of about 85° to about 105°. In addition, the inner angle θ may be in the range of about 85° to about 120°, and more specifically, in the range of about 85° to about 105°. The inner angle θ and the outer angle φ may take approximately the same value.

[0019] In particular, the base segment extends substantially in a circumferential direction directly connected to the side segment. The side segment extends substantially in a radial direction. Thus, one end of the side segment is oriented substantially in a radial direction. In this context, the term "substantially extending in a radial direction" means that the side segment extends in a radial direction within the boundaries represented by the outer angle.

[0020] In particular, the side segments are directly connected to the top segment. The top segment extends substantially in a circumferential direction. Thus, the ends of the top segment are oriented substantially in a circumferential direction. In this context, the term "substantially extending in a circumferential direction" means that the top segment extends in a circumferential direction within the boundaries represented by the inner angle. In particular, when viewed in the axial direction, the base segment, the side segments, and the top segment form a Z-shaped profile.

[0021] In particular, the support structure includes one or more of the above-mentioned carrier elements. These carrier elements are arranged spaced apart from each other in the circumferential direction and extend generally in the axial direction. Specifically, the carrier element includes the above-mentioned top segment, base segment, and side segments. The top segment is arranged in a top plane, the base segment is arranged in a base plane, and the side segments are arranged in a side plane. The top segment, base segment, and side segments extend parallel to each other in a longitudinal direction, for example, in an axial direction. The top plane and the side plane (i.e., their normals) have an internal angle of approximately 70° to approximately 130°, particularly 90°, with respect to each other. The base plane and the side plane (i.e., their normals) have an external angle of approximately 70° to approximately 130°, particularly 90°, with respect to each other.

[0022] According to an embodiment of the invention, each cooling slot extends along the longitudinal axis between two connections, each connection being performed by two connecting elements coupling two respective circumferentially adjacent carrier elements.

[0023] According to one embodiment, the carrier element is an integrally formed carrier element, in particular an integrally formed metal carrier element.

[0024] The manufacture of the integrally formed carrier element is cost-effective and allows the size and measure of the carrier element to be easily adapted to the size and measure of the generator it is provided for. Thus, scaling of the support structure, i.e. adjusting the support structure to accommodate generators of different sizes and measures, becomes efficiently possible.

[0025] According to one embodiment, the support structure comprises at least two carrier elements.

[0026] In particular, the supporting structure segment comprises at least 3, 4, 5, 6 or 7 or even more carrier elements.

[0027] By providing a plurality of carrier elements, a stable coupling of the support structure to the laminated section can be achieved. In addition, each of the plurality of individual carrier elements can be spaced apart, and an opening can be formed between two adjacent carrier elements, the opening allowing air to flow in a radial direction.

[0028] The above-defined aspects of the present invention as well as further aspects will be apparent from the examples of embodiment described hereinafter and will be explained with reference to these examples of embodiment. The invention will be described in more detail hereinafter with reference to examples of embodiment, but the invention is not limited to these examples of embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A schematic cross-sectional view of a wind turbine according to the invention is shown, comprising a generator with a stator.

[0030] Figure 2 An exploded view of a generator with a stator according to the invention is shown.

[0031] Figure 3 Shown Figure 2 Axonometric view of a segment of the stator.

[0032] Figure 4 Shown Figure 3 The first part of the segment.

[0033] Figure 5 Shown Figure 3 The second part of the segment.

[0034] Figure 6 The first axonometric view from the bottom shows Figure 3 The supporting structure of the segment.

[0035] Figure 7 The second axonometric view from the top shows Figure 3 The supporting structure of the segment.

[0036] Figure 8 A carrier element of a support structure according to an exemplary embodiment of the present invention is shown in a perspective view. DETAILED DESCRIPTION

[0037] The illustrations in the drawings are schematically shown. It should be noted that in different drawings, similar or identical elements are provided with the same reference signs.

[0038] Figure 1 A wind turbine 1 according to the invention is shown. The wind turbine 1 comprises a tower 2, which is mounted on a foundation (not depicted). A nacelle 3 is arranged on top of the tower 2. The wind turbine 1 further comprises at least a wind rotor 5 having a hub and at least one blade 4 (at Figure 1 In the embodiment of the present invention, the wind rotor comprises three blades 4, of which only two blades 4 are visible. The wind rotor 5 is rotatable about a longitudinal axis of rotation Y. The blades 4 extend substantially radially relative to the longitudinal axis Y. In general, the terms "axial", "radial" and "circumferential" hereinafter are made with reference to the longitudinal axis of rotation Y, unless otherwise specified. The wind turbine 1 comprises at least one generator 11, which comprises a stator 20 and a rotor 30. The rotor 30 is rotatable relative to the stator 20 about the longitudinal axis of rotation Y. The wind rotor 5 is coupled to the rotor 30, and both are connected to the outer ring of the main bearing assembly 8. The outer ring of the main bearing assembly 8 rotates about the longitudinal axis of rotation Y relative to a stationary inner ring, which is coupled to the main shaft 9 extending along the longitudinal axis Y.

[0039] Figure 2 An exploded view of a generator 11 having a rotor 30 and a stator 20 is shown. The stator 20 comprises a cylindrical inner core 21 to which six segments 45 are attached. Each segment 45 has a circumferential angular extension of 60°. According to other embodiments of the invention, the stator 20 comprises a plurality of segments having a number of segments different from six. According to another possible embodiment of the invention, the stator 20 is not segmented, i.e. it comprises a single segment covering the entire angular extension of 360°. The rotor 30 has a conventional structure with a plurality of circumferentially distributed rotor permanent magnets 31.

[0040] Figures 3 to 5 The stator segment 45 is shown in more detail. The stator segment 45 has a conventional structure, which includes a plurality of teeth circumferentially arranged between a plurality of slots. These teeth protrude in a radial direction. The stator segment 45 also includes coil windings 48 inserted into the slots of the segment 45. The teeth, slots and windings 48 are not the specific purpose of the present invention and are therefore not described in further detail. Each segment 45 includes a support structure 50 and a lamination stack 60 supported by the support structure 50. The support structure 50 extends circumferentially between two circumferential ends 46. At each circumferential end 46, a corresponding flat bar 51 is provided. The flat bar 51 can be used to connect the plurality of segments 45 together, for example by means of a plurality of bolts or by welding. The lamination stack 60 includes a plurality of laminations attached one after another along the longitudinal axis Y of the stator 20. The lamination stack 60 is fixed to the support structure 50, as better explained below. When the stator segments 45 are circumferentially coupled together, the assembly formed by all the support structures 50 and the lamination stack 60 constitutes the stator body. According to a possible embodiment of the invention in which the stator 20 is not segmented, the stator body is made of a single support structure 50 and a single lamination stack 60, both covering the entire angular extension of 360°. In this latter embodiment, the flat bars 51 are not present.

[0041] Figure 6 and Figure 7 A support structure 50 for a segment 45 according to an embodiment of the present invention is shown in two perspective views, one from the bottom and the other from the top. The support structure segment 50 is configured for use in a stator of a wind turbine. The support structure segment 50 includes a plurality of carrier elements 200. Each carrier element 200 has a cross-section approximately in the shape of the Greek letter "omega" (Ω), extending along a longitudinal axis Y. The carrier elements 200 are symmetrical about a mirror plane, wherein the mirror plane passes through the carrier element 200 in the middle such that the top segment 203 is substantially perpendicular to the mirror plane, and the mirror plane is perpendicular to the circumferential direction.

[0042] The support structure segment 50 further comprises two pressure plates 240, respectively at the two longitudinal ends of the support structure 50. Each of the two pressure plates 240 is fixed to the inner core 21 of the stator 20, for example by welding. Each carrier element 200 extends longitudinally from one of the two pressure plates 240 to the other.

[0043] Figure 8 A perspective view shows a plurality of carrier elements 200 for a support structure segment 50 according to an embodiment of the present invention. Each carrier element 200 includes first and second base segments 201, first and second side segments 202, and a top segment 203. The base segments 201 and top segments 203 span circumferentially, while the side segments span radially. Each base segment 201 is connected to a corresponding side segment 202, oriented relative to each other at an external angle φ of approximately 90°. Each side segment is connected to the top segment 203. Each side segment 202 forms an internal angle θ of approximately 90° with the top segment 203. The base segment 201 and the top segment 203 are spaced substantially radially apart. The first and second side segments are spaced circumferentially apart.

[0044] According to another embodiment of the invention, at least one carrier element 200 comprises only one base section 201, in particular in the circumferential end section 51 ( Figure 3 ), the base section 201 can be formed by a side section 202 of the carrier element 200. In this case, the carrier element 200 has a cross section approximately in the shape of the Latin letter "Z", which extends along the longitudinal axis Y.

[0045] The top section 203 is configured to be coupled to the lamination stack 60. This connection is established by means of a fixed connection, for example, by means of bolts. To establish such a fixed connection, bolt holes can be provided in the top section 203. To this end, the top section 203 forms a plateau having a surface area that is appropriately extended to enable the bolt holes to be formed therein and the bolts to be securely fixed therein.

[0046] The carrier element 200 can be a single-piece carrier element, particularly one formed integrally from a metal or metal alloy. The carrier element is comprised of a first base segment 201, a first side segment 202, a top segment 203, a second side segment 202, and a second base segment 201 in this order from one circumferential end to the other. At the transition interfaces between these segments, the carrier element 200 forms rounded edges.

[0047] The base section 201 of at least one carrier element 200 of the plurality of carrier elements 200 is connected to the base section 201 of another carrier element 200 of the plurality of carrier elements 200. Each connection may be performed, for example, by means of welding.

[0048] refer to Figures 6 to 8 In this embodiment, multiple connections (four connections shown in the figure) are established between each base segment 201 of one carrier element 200 and the base segment 201 of another circumferentially adjacent carrier element 200. These connections are distributed along the longitudinal axis Y, for example, regularly spaced along the longitudinal axis Y, with a constant distance between each connection. These connections are established via multiple connection elements 205 circumferentially projecting from one base segment 201 of one carrier element 200 and connected, for example, welded, to another plurality of connection elements 205 circumferentially projecting from one base segment 201 of another carrier element 200. Cooling pockets 206 are formed between the connection elements 205 for passage of cooling air. Each cooling pocket 206 extends along the longitudinal axis Y between two connections, each connection being established by coupling two connection elements 205 of two corresponding circumferentially adjacent carrier elements 200. According to other embodiments of the present invention (not shown), any number of connecting elements, such as one connection, two connections, three connections, or any number greater than four connections, may be provided between each base segment 201 of one carrier element 200 and the base segment 201 of another circumferentially adjacent carrier element 200. The number of cooling slots 206 is determined accordingly; for example, five cooling slots 206 are provided in the embodiment shown in the drawings.

[0049] According to another embodiment of the present invention (not shown), at least one base segment 201 of one carrier element 200 extends circumferentially into the base segment 201 of another circumferentially adjacent carrier element 200. The two base segments 201 of the two circumferentially adjacent carrier elements 200 are connected together, for example, by welding. In such an embodiment, the cooling slot cavities 206 are not present.

[0050] The connections between the carrier elements 200 provide a plurality of circumferential reinforcements, such that no additional circumferential reinforcements may be required in the support structure 50 .

[0051] It should be noted that the term "comprising" does not exclude other elements or steps, and the wording "a", "an" or "an" does not exclude a plurality. Furthermore, elements described in connection with different embodiments may also be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

Claims

1. A support structure (50) for a stator (20) of a generator (11) of a wind turbine (1), wherein: The support structure (50) extends along a longitudinal axis (Y) and comprises a plurality of carrier elements (200), each carrier element (200) comprising a base section (201), side sections (202) and a top section (203), wherein The base section (201) and the side section (202) are oriented relative to each other at an external angle (φ) in the range of 70° to 130°, The side segments (202) and the top segment (203) are oriented relative to each other at an internal angle (θ) in the range of 70° to 130°, The base section (201) is connected to the side section (202), The side sections (202) are connected to the top section (203), The base section (201) is spaced apart from the top section (203) substantially in a radial direction orthogonal to the longitudinal axis (Y), wherein the base section (201) of at least one carrier element (200) of the plurality of carrier elements (200) is connected to the base section (201) of another carrier element (200) of the plurality of carrier elements (200), It is characterized by: A plurality of circumferential connecting elements (205) protruding circumferentially from the base section (201) of one carrier element (200) are connected to another plurality of connecting elements (205) protruding circumferentially from the base section (201) of another carrier element 200, so as to provide a connection between the one carrier element (200) and the other carrier element (200), and a plurality of cooling slots (206) are formed between the connecting elements (205) for cooling air to pass through.

2. The support structure (50) according to claim 1, wherein Each cooling slot cavity (206) extends along the longitudinal axis (Y) between two connections, each connection being performed by two connection elements (205) coupling two respective circumferentially adjacent carrier elements (200).

3. The support structure (50) according to claim 1 or 2, wherein: The base section (201) of one carrier element (200) among the plurality of carrier elements (200) is connected to the base section (201) of another carrier element (200) among the plurality of carrier elements (200) by welding.

4. The support structure (50) according to claim 1 or 2, wherein: The carrier element (200) is an integrally formed carrier element.

5. The support structure (50) according to claim 1 or 2, wherein: The top section (203) is configured to be coupled to a lamination stack (60) of the stator (20) by means of a fixed connection.

6. The support structure (50) according to claim 1 or 2, wherein The carrier element (200) includes first and second side sections (202) coupled to the top section (203) and spaced apart from each other in a circumferential direction about the longitudinal axis.

7. The support structure (50) according to claim 6, wherein A circumferential end section (51) of the support structure (50) is formed by a side section (202) of the carrier element (200).

8. The support structure (50) according to claim 6, wherein The carrier element (200) further comprises first and second base sections (201), both coupled to first and second side sections (202), respectively, and spaced apart from the top section (203) in the radial direction.

9. The support structure (50) according to claim 4, wherein: The carrier element (200) is an integrally formed metal carrier element.

10. A stator (20) for a generator (11) of a wind turbine (1), wherein: The stator (20) includes: a lamination stack (60), and At least one support structure (50) according to any one of claims 1-9.

11. The stator (20) according to claim 10, wherein: The stator (20) has a circumferentially segmented structure comprising a plurality of support structures (50) according to any one of claims 1-8.

12. A generator (11) for a wind turbine (1), comprising a stator according to claim 10 or 11.

13. A wind turbine (1) comprising a generator (11) according to claim 12.

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