Support structure and segmented stator for an electric machine, wind turbine and method of manufacturing a support structure

Abstract

A support structure (1) for supporting a stack of laminations and a winding structure so as to form a stator segment (20) for an electric machine, in particular a wind turbine generator, is described, the support structure comprising: (a) a frame comprising two parallel end plates (2, 3) and two side plates (4, 5) extending between corresponding ends of the end plates, (b) a plurality of internal connection members (6) extending within the frame between the end plates, and (c) a plurality of external connection members (7, 8) extending outside the frame, each external connection member forming an extension of a corresponding internal connection member beyond one of the end plates, wherein (d) the internal and external connection members are adapted to engage with corresponding fastening members so as to secure a stack of laminations. Furthermore, a stator segment (20), a wind turbine generator and a method of manufacturing a support structure are described.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more particularly to a support structure for supporting laminated stacks and winding structures to form stator segments for electric motors, especially wind turbine generators, and a method for manufacturing such a support structure. The invention also relates to a stator and a wind turbine including such a stator. Background Technology

[0002] When designing segmented stators for large electric motors, such as wind turbine generators, many aspects and constraints must be considered. In many cases, it is impossible to utilize the maximum stator length due to the boundary conditions of surrounding components and the design of the segment support structure itself. This results in lower performance compared to the theoretically available performance. Consequently, the result is lower torque with lower output power. Therefore, it is desirable to maximize the generator's torque output without significantly increasing the generator's cost. To utilize the maximum stator length, a significantly more complex segment support structure design would be required. However, this would significantly increase the cost.

[0003] Typically, segmental support structures are designed with a simple machined pressure plate and an integral finger plate at one end. Electrically laminated steel is stacked encapsulated from the integrated finger plate to the other end of the support structure. The laminates are enclosed within the support structure by bolting or welding to the finger plate in the open end of the support structure. However, this introduces numerous boundary conditions for the length of the electrical steel, as the support structure encloses the laminate stack within the width of the support structure.

[0004] Therefore, a flexible way to increase the effective size of the stator without increasing complexity and corresponding costs may be needed. Summary of the Invention

[0005] This need can be met by the subject matter of the basic scheme of this application. Advantageous embodiments of the invention are described in the preferred embodiments of this application.

[0006] According to a first aspect of the invention, a support structure is provided for supporting laminated stacks and winding structures to form stator segments for electric motors, particularly wind turbine generators. The support structure includes: (a) a frame comprising two parallel end plates and two side plates extending between corresponding ends of the end plates; (b) a plurality of internal connecting members extending within the frame between the end plates; and (c) a plurality of external connecting members extending outside the frame, each external connecting member forming an extension of a corresponding internal connecting member beyond one of the end plates; wherein (d) the internal and external connecting members are adapted to engage with corresponding fastening members to secure the laminated stack.

[0007] This aspect of the invention is based on the idea that by adding external connecting members, the effective length of the support structure extends beyond the length of the frame. These external connecting members extend outside the frame, thereby lengthening the internal connecting members within the frame and adding to the total length of the connecting members. Thus, the resulting support structure can support larger lamination stacks. The amount of extension can be chosen based on available space, allowing for relatively simple optimization of the resulting generator.

[0008] According to an embodiment of the present invention, the external connecting member has a U-shaped cross-section.

[0009] The U-shape is advantageous because the legs of the profile provide strength and can be secured to the corresponding end plates, while the bottom (or top, depending on the orientation) can be used to engage with fastening members to secure the stack of plates.

[0010] According to another embodiment of the invention, the U-shaped cross-section has a height that decreases as the distance from the corresponding end plate increases.

[0011] In other words, the legs of this profile have their maximum length at the corresponding end plate and shorten as the distance from the end plate increases. This shape ensures a secure connection to the end plate while occupying less space in the area outside the frame.

[0012] According to another embodiment of the invention, an external connecting member extending from one of the end plates has a first length, and an external connecting member extending from the other of the end plates has a second length.

[0013] In other words, the length of the extension from one end plate can be different from or equal to the length of the extension from the other end plate. Although symmetrical structures (with equal first and second lengths) may be preferred in many cases, the flexibility provided by the present invention to have extensions of different lengths can be very useful in some cases, for example, to leave sufficient space at one end of the stator for other structural components.

[0014] According to another embodiment of the invention, the first length and the second length are between 5% and 25% of the length of the stack, for example, about 15%.

[0015] According to another embodiment of the invention, each of the internal connecting member and the external connecting member includes a plurality of holes for allowing bolted connection with the corresponding fastening member.

[0016] Fastening members can be integrated into the laminated material, or they can be separate (i.e., intermediate) components also connected to the laminated material. An example of a separate component is a rod shaped to fit into a corresponding recess in the laminated material to form a dovetail connection between the support structure and the laminated material. Fastening members integrated into the laminated material can simply be sections of laminated material to be welded to the connecting member. Alternatively, integrated fastening members can be fastening structures shaped to receive bolts or some other type of fastening element.

[0017] According to another embodiment of the invention, the end plate has an arcuate shape.

[0018] The arc shape ensures that several segments can be arranged side by side to form a circular stator.

[0019] According to another embodiment of the invention, at least one of the end plates is adapted to be connected to the finger plate via a finger plate connection structure.

[0020] The completed stator segment may have finger plates at both ends of the structure, each finger plate forming a boundary for the lamination stack. Once the lamination stack has been formed (on top of another previously installed finger plate), the finger plate connection structure is particularly useful for the finger plates.

[0021] According to another embodiment of the present invention, the end plate includes a plurality of holes, and the finger plate connection structure includes a plurality of cylindrical spacers and a plurality of bolts.

[0022] The cylindrical spacers have a length substantially the same as the external connecting members. More specifically, the cylindrical spacers may be slightly shorter than the external connecting members, or they may have the same length as the external connecting members. It should be noted that the length of the spacers must not exceed the length of the external connecting members. Therefore, the finger plates can be arranged and secured to the ends of the external connecting members by pushing each bolt through a hole in the end plate and further through the cylindrical spacer and into a threaded hole in the finger plate. Alternatively, the finger plates may include unthreaded holes. In this case, nuts can be used to tighten the bolts.

[0023] According to another embodiment of the invention, each of the two side plates includes a side connecting member for mechanically connecting the support structure to an adjacent support structure.

[0024] Side-connecting members can specifically utilize bolts and nuts to mechanically connect adjacent support structures.

[0025] According to a second aspect of the invention, a stator for an electric motor, particularly a wind turbine generator, is provided, the stator comprising a plurality of interconnected stator segments, wherein each stator segment includes a support structure, lamination stack, and winding structure as described in the first aspect or any of the above embodiments.

[0026] This aspect of the invention is largely based on the same idea as the first aspect and takes advantage of the aforementioned advantages to provide a larger and more efficient stator without significantly increasing costs.

[0027] According to a third aspect of the invention, a wind turbine is provided, which includes a stator according to the second aspect.

[0028] Compared to similar wind turbines without an extended stator, wind turbines based on this aspect will be able to generate significantly more power over their lifespan without significantly increasing manufacturing costs.

[0029] According to a fourth aspect of the invention, a method for manufacturing a support structure for supporting laminated stacks and winding structures to form stator segments for electric motors, particularly wind turbine generators, is provided. The method includes: (a) providing a frame including two parallel end plates and two side plates extending between corresponding ends of the end plates; (b) providing a plurality of internal connecting members extending within the frame between the end plates; and (c) providing a plurality of external connecting members extending outside the frame, each external connecting member forming an extension of a corresponding internal connecting member beyond one of the end plates; wherein, (d) the internal and external connecting members are adapted to engage with corresponding fastening members to secure the laminated stack.

[0030] This aspect of the invention is substantially based on the same idea as the first aspect described above.

[0031] Note that embodiments of the invention have been described with reference to different categories of subject matter. In particular, some embodiments have been described with reference to method type claims, while others have been described with reference to device type claims. However, those skilled in the art will understand from the above and below description that, unless otherwise indicated, any combination of features relating to different types of subject matter, particularly combinations of features from method type claims and device type claims, is also part of the disclosure of this document, in addition to any combination of features belonging to one type of subject matter.

[0032] The above and other aspects of the invention will become apparent from the examples of the embodiments described below, and will be explained with reference to these examples. The invention will now be described in more detail with reference to examples of embodiments. However, it should be clearly noted that the invention is not limited to the exemplary embodiments described. Attached Figure Description

[0033] Figure 1 A perspective view of a support structure according to an embodiment of the present invention is shown.

[0034] Figure 2 It shows Figure 1Another perspective view of the supporting structure shown.

[0035] Figure 3 It shows Figure 1 and Figure 2 The top view of the support structure shown.

[0036] Figure 4 A partial view of a support structure with finger plates according to an embodiment of the present invention is shown.

[0037] Figure 5 A stator segment according to an embodiment of the present invention is shown. Detailed Implementation

[0038] The illustrations in the accompanying drawings are schematic. Note that in different drawings, similar or identical elements are given the same reference numerals or reference numerals that differ only in the first digit.

[0039] Figure 1-3 Different views of the support structure 1 according to an embodiment of the present invention are shown. More specifically, Figure 1 A perspective view of support structure 1 is shown. Figure 2 Another perspective view of support structure 1 is shown, and Figure 3 A top view of support structure 1 is shown. Support structure 1 is particularly suitable for supporting laminated stacks and winding structures to form stator segments for electric motors, especially wind turbine generators.

[0040] The support structure 1 includes two parallel end plates 2, 3 and two side plates 4, 5 extending between the corresponding ends of the end plates 2, 3, thus forming a generally rectangular frame. The end plates 2, 3 have an arcuate shape, allowing the support structure 1 to be combined with several similar structures to form a ring-shaped support structure around an axis of rotation parallel to the side plates 4, 5. To allow for this connection with adjacent structures, each side plate 4, 5 includes a plurality of side connecting members 9 for bolting the segments together.

[0041] Multiple internal connecting members 6 extend within the frame between end plates 2 and 3. In the specific embodiment shown, there are five internal connecting members 6, but those skilled in the art will understand that any other number of internal connecting members 6 is possible, such as two, three, four, six, seven or more.

[0042] Furthermore, multiple external connecting members 7 and 8 extend outside the frame. Each external connecting member 7 or 8 forms an extension of a corresponding internal connecting member 6 beyond one of the end plates. More specifically, the external connecting member 7 extends away from the end plate 2, while the external connecting member 8 extends away from the end plate 3. Thus, a corresponding number (five in this exemplary embodiment) of combined connecting members are formed, each combined connecting member consisting of an internal connecting member 6, an external connecting member 7 located on the end plate 2 side, and an external connecting member 8 located on the end plate 3 side. Therefore, the total length of each combined connecting member exceeds the length of the frame by the length of two external connecting members 7 and 8. In this exemplary embodiment, the length of the external connecting member 7 is substantially equal to the length of the external connecting member 8. However, in other exemplary embodiments of the invention, the length of the external connecting member 7 may differ from the length of the external connecting member 8.

[0043] The internal connecting member 6 and the external connecting members 7 and 8 are configured to engage with corresponding fastening members (not shown) to secure the stack of sheets to the top of the support structure 1. As shown, particularly... Figure 3 In this embodiment, this is achieved by providing elongated, flat surfaces facing the laminated material (not shown) for the inner connecting member 6 and the outer connecting members 7, 8, in which a plurality of holes 10 are provided. The holes 10 allow bolts or other fastening elements to extend through the surface and into the fastening members of the laminated stack, such as rods, thereby forming a dovetail connection with the laminated stack.

[0044] External connecting members 7 and 8 have a U-shaped profile or cross-sectional shape, wherein the surface with the hole 10 forms the bottom of the U-shape. For example... Figure 1 and Figure 2 As shown, the U-shaped legs are longer near end plates 2 and 3, and shorten as the distance from end plates 2 and 3 increases. This provides the required strength and stability with minimal material, while leaving as much space as possible for other components (such as windings, busbars, etc.).

[0045] Figure 4 A partial view of a support structure 1 with a finger plate 13 according to an embodiment of the present invention is shown. The finger plate 13 forms the boundary of the (to be installed) lamination stack and includes a plurality of teeth or fingers 14 that allow the winding structure to extend into and out of the lamination stack. The finger plate 13 is displaced from the end plate by an amount corresponding to the length of the external connecting member. In this exemplary embodiment, this is achieved by arranging a plurality of cylindrical spacers 12 and bolts 11 extending from the inside of the end plate through the spacers 12 and into the finger plate 13, wherein the bolts 11 are fastened by threads in the finger plate 13 or by nuts on the outside of the finger plate 13.

[0046] Figure 5A stator segment 20 according to an embodiment of the present invention is shown. The stator segment 20 includes the support structure as described above and a lamination stack consisting of a plurality of lamination groups 15 arranged between finger plates 13 and fastened to internal and external fastening members 6, 7, 8 of the support structure 1. A winding structure 14 is arranged within the lamination stack.

[0047] It can be seen that the length of the laminated stack 15 exceeds the length between end plates 2 and 3 by an amount corresponding to the length of the external fastening members 7 and 8. Therefore, by adding external connecting members 7 and 8, the length of the laminated stack 15 can be maximized in a flexible manner, the length of which is suitable for the rest of the generator design and constraints, without altering the basic frame formed by end plates 2 and 3 and side plates 4 and 5. In this way, the maximum torque of the generator can be optimized in a flexible manner. Considering, for example, a twenty-year lifespan, this optimization can accumulate into significant power generation.

[0048] Note that the term "comprising" does not exclude other elements or steps, and the use of the articles "a" or "an" does not exclude a plurality. Furthermore, elements described in connection with different embodiments may be combined. It should also be noted that reference numerals in the claims should not be construed as limiting the scope of the claims.

Claims

1. A support structure (1) for supporting laminated stacks and winding structures to form a stator segment (20) for an electric motor, the support structure comprising: The frame includes two parallel end plates (2, 3) and two side plates (4, 5), the side plates extending between corresponding ends of the end plates. Multiple internal connecting members (6) extending within the frame between the end plates, and Multiple external connecting members (7, 8) extend outside the frame, each external connecting member forming an extension of a corresponding internal connecting member beyond one of the end plates. The internal and external connecting members are adapted to engage with corresponding fastening members to secure the stack of plates, wherein the external connecting member has a U-shaped cross-section, and the height of the U-shaped cross-section decreases as the distance from the corresponding end plate increases.

2. The support structure according to claim 1, wherein, An external connecting member extending from one of the end plates has a first length, and an external connecting member extending from the other of the end plates has a second length.

3. The support structure according to claim 2, wherein, The first length and the second length are between 5% and 25% of the length of the stack.

4. The support structure according to any one of claims 1-3, wherein, Each of the internal and external connecting members includes a plurality of holes (10) for allowing bolted connection with the corresponding fastening member.

5. The support structure according to any one of claims 1-3, wherein, The end plate has an arc shape.

6. The support structure according to any one of claims 1-3, wherein, At least one of the end plates is adapted to be connected to the finger plate via a finger plate connection structure.

7. The support structure according to claim 6, wherein, The end plate includes multiple holes, and the finger plate connection structure includes multiple cylindrical spacers (12) and multiple bolts (11).

8. The support structure according to any one of claims 1-3, wherein, Each of the two side plates includes a side connecting member (9) for mechanically connecting the support structure to an adjacent support structure.

9. The support structure according to any one of claims 1-3, wherein, The motor is a wind turbine generator.

10. A stator for an electric motor, the stator comprising a plurality of interconnected stator segments (20), wherein, Each stator segment includes a support structure (1), a lamination stack (15), and a winding structure (14) according to any one of claims 1-9.

11. The stator according to claim 10, wherein, The motor is a wind turbine generator.

12. A wind turbine comprising a stator according to any one of claims 10-11.

13. A method of manufacturing a support structure for supporting laminated stacks and winding structures to form a stator segment for an electric motor, the method comprising: A frame is provided, comprising two parallel end plates and two side plates extending between corresponding ends of the end plates. Provides a plurality of internal connecting members that extend within the frame between the end plates, and A plurality of external connecting members are provided, extending outside the frame, each external connecting member forming an extension of a corresponding internal connecting member beyond one of the end plates. The internal and external connecting members are adapted to engage with corresponding fastening members to secure the stack of plates, wherein the external connecting member has a U-shaped cross-section, and the height of the U-shaped cross-section decreases as the distance from the corresponding end plate increases.

14. The method according to claim 13, wherein, The motor is a wind turbine generator.

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