SUPPORT STRUCTURE AND SEGMENTED STATOR FOR AN ELECTRIC MACHINE, WIND TURBINE AND METHOD OF MANUFACTURING A SUPPORT STRUCTURE

Abstract

A support structure for supporting a lamination stack and a winding structure in order to form a stator segment for an electric machine, in particular a wind turbine generator including (a) a frame including two parallel end plates and two side plates, the side plates extending between corresponding end portions 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 of 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 for securing a lamination stack. A stator segment, a wind turbine generator, and a method of manufacturing a support structure are also described.

Claims

1. A support structure for supporting a lamination stack and a winding structure to form a stator segment for an electric machine, the support structure comprising a frame comprising two parallel end plates and two side plates, the side plates extending between corresponding end portions of the end plates, a plurality of internal connecting members extending within the frame between the end plates, and a plurality of external connecting members extending outside of the frame, each external connecting member forming an extension of a corresponding internal connecting member beyond one of the end plates, wherein the internal and external connecting members are adapted to engage with corresponding fastening members for securing a lamination stack.

2. The support structure according to claim 1, wherein the external connecting members have a u-shaped cross section.

3. The support structure according to claim 2, wherein the u-shaped cross section has a height that decreases with increasing distance away from the corresponding end plate.

4. The support structure according to claim 1, wherein the external connecting members extending from one of the end plates have a first length and the external connecting members extending from the other one of the end plates have a second length.

5. The support structure according to claim 4, wherein the first length and the second length are between 5% and 25% of the length of the lamination stack.

6. The support structure according to claim 1, wherein each of the internal connecting members and external connecting members comprises a plurality of holes for allowing a bolt connection with the corresponding fastening members.

7. The support structure according to claim 1, wherein the end plates have an arc-like shape.

8. The support structure according to claim 1, wherein at least one of the end plates is adapted to be connected to a finger plate via a finger plate connecting structure.

9. The support structure according to claim 1, wherein the end plate comprises a plurality of holes, and wherein the finger plate connecting structure comprises a plurality of cylindrical spacers and a plurality of bolts.

10. The support structure according to claim 1, wherein each of the two side plates comprises side connecting members for mechanically connecting the support structure with a neighboring support structure.

11. A stator for an electric machine, in particular a wind turbine generator, the stator comprising a plurality of interconnected stator segments, wherein each stator segment comprises the support structure according to claim 1, a lamination stack and a winding structure.

12. A wind turbine comprising the stator according to claim 11.

13. A method of manufacturing a support structure for supporting a lamination stack and a winding structure in order to form a stator segment for an electric machine, the method comprising providing a frame comprising two parallel end plates and two side plates, the side plates extending between corresponding end portions of the end plates, providing a plurality of internal connecting members extending within the frame between the end plates, and providing a plurality of external connecting members extending outside of the frame, each external connecting member forming an extension of a corresponding internal connecting member beyond one of the end plates, wherein the internal and external connecting members are adapted to engage with corresponding fastening members for securing a lamination stack.

Description

BRIEF DESCRIPTION

[0032] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0033] FIG. 1 shows a perspective view of a support structure according to an embodiment of the present invention;

[0034] FIG. 2 shows a further perspective view of the support structure shown in FIG. 1;

[0035] FIG. 3 shows a top view of the support structure shown in FIGS. 1 and 2;

[0036] FIG. 4 shows a partial view of a support structure with a finger plate according to an embodiment of the present invention; and

[0037] FIG. 5 shows a stator segment according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0038] The illustration in the drawing is schematic. It is noted that in different figures, similar or identical elements are provided with the same reference numerals or with reference numerals which differ only within the first digit.

[0039] FIGS. 1-3 show different views of a support structure 1 according to an embodiment of the present invention. More specifically, FIG. 1 shows one perspective view of the support structure 1, FIG. 2 shows another perspective view of the support structure 1, and FIG. 3 shows a top view of the support structure 1. The support structure 1 is particularly suitable for supporting a lamination stack and a winding structure in order to form a stator segment for an electric machine, in particular a wind turbine generator.

[0040] The support structure 1 comprises two parallel end plates 2, 3 and two side plates 4, 5 extending between corresponding end portions of the end plates 2, 3, thereby forming a substantially rectangular frame. The end plates 2, 3 have an arc-like shape such that the support structure 1 can be combined with several similar structures to form an annular stator structure around an axis of rotation, the axis of rotation being parallel to the side plates 4, 5. To allow such connections with neighboring structures, each side plate 4, 5 comprises a plurality of side connecting members 9 for bolting the segments together.

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

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

[0043] The internal 6 and external 7, 8 connecting members are configured to engage with corresponding fastening members (not shown) for securing a lamination stack on top of the support structure 1. As shown, particularly in FIG. 3, this is achieved in the present embodiment by providing both the internal connecting members 6 and the external connecting members 7, 8 with an elongate flat surface facing toward the lamination material (not shown), in which surface a plurality of holes 10 is provided. The holes 10 allow bolts or other fastening elements to extend through the surface and into fastening members of a lamination stack, such as a rod forming a dovetail connection with the lamination stack.

[0044] The external connecting members 7, 8 have a u-shaped profile or cross-sectional shape, where the aforementioned surface with holes 10 constitutes the bottom of the u-shape. As shown in FIG. 1 and FIG. 2, the legs of the u-shape are longer in the vicinity of the end plates 2, 3 and gets shorter with increasing distance away from the end plates 2, 3. Thereby, the required strength and stability is provided with a minimum of material while leaving as much space as possible for other parts, such as windings, busbars, etc.

[0045] FIG. 4 shows a partial view of support structure 1 with a finger plate 13 according to an embodiment of the present invention. The finger plate 13 forms a border for the (to be mounted) lamination stack and comprises a plurality of teeth or fingers 14 that allow a winding structure to extend in and out of the lamination stack. The finger plate 13 displaced from the end plate by an amount corresponding to the length of the external connecting members. In the present exemplary embodiment this is achieved by arranging a plurality of cylindrical hollow spacers 12 and bolts 11 extending from the inner side of the end plate through the spacers 12 and into the finger plate 13 where it is fastened either by a thread in the finger plate 13 or by a nut on the outside of the finger plate 13.

[0046] FIG. 5 shows a stator segment 20 according to an embodiment of the present invention. The stator segment 20 comprises a support structure as the one discussed above and a lamination stack constituted by a plurality of lamination packets 15 arranged between finger plates 13 and fastened to the internal and external fastening members 6, 7, 8 of the support structure 1. A winding structure 14 is arranged within the lamination stack.

[0047] As can be seen, the length of the lamination stack 15 exceeds the length between the end plates 2 and 3 by an amount corresponding to the lengths of external fastening members 7, 8. Hence, it is possible to maximize the length of the lamination stack 15 in a flexible manner by adding the external connecting members 7, 8 with lengths that fit the remaining generator design and constraints but without changing the basic frame constituted by end plates 2, 3 and side plates 4, 5. In this way, the maximum torque of the generator can be optimized in a flexible manner. Looking at a lifetime of e.g., twenty years, this optimization can accumulate to a significant amount of power production.

[0048] 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.

[0049] 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.