EP3143679A1

EP3143679A1 - Synchronous generator of a gearless wind turbine

Info

Publication number: EP3143679A1
Application number: EP15718860.8A
Authority: EP
Inventors: Jochen RÖER; Wojciech GIENGIEL
Original assignee: Wobben Properties GmbH
Current assignee: Wobben Properties GmbH
Priority date: 2014-05-13
Filing date: 2015-04-23
Publication date: 2017-03-22
Also published as: CN106415997A; DE102014209006A1; TWI578665B; WO2015172991A1; AR101160A1; CA2948207A1; UY36119A; TW201613230A; US20170264165A1

Abstract

The invention relates to a synchronous generator (1), in particular a multi-pole synchronous ring generator of a gearless wind turbine (100), for generating an electric current, comprising a rotor (4) and a stator (3). According to the invention, the stator (3) has a plurality of grooves (17) for receiving a stator coil in the form of conductor bundles (L). Each of the grooves has a groove base (21), the surface of which is profiled such that a first groove base-side layer (25) of conductor bundles assumes an orientation which is specified by the profile when the groove is filled. The invention further relates to a stator (3) for such a generator and to a wind turbine (100) with such a generator.

Description

Synchronous generator of a gearless wind turbine

The present invention relates to a synchronous generator, in particular a multi-pole synchronous ring generator of a gearless wind turbine. Furthermore, the present invention relates to a generator stator for such a synchronous generator and to a wind turbine with such a synchronous generator. In the priority German application, the German Patent and Trademark Office has investigated the following documents DE 10 2011 078 025 A1, US 2005/0 029889 A1, AT 513 114 A1, DE 20 1011 078025 A1 and US 2005/0 218 744 A1.

Wind turbines are well known They generate electricity from wind by means of a generator. Modern gearless wind turbines often have a much pol igen synchronous ring generator with a large air gap diameter. The diameter of the air gap is at least four meters and usually extends to almost five meters. Synchronous generators composed of several parts may well have air gap diameters in the range of ten meters or more. The efficiency of the synchronous generator significantly influences the efficiency of the entire wind turbine when generating electricity. In order to achieve the highest possible efficiency in power generation, it is therefore important to make the stator winding optimal. This also includes, as far as possible to accommodate a large number Lelterböndel in the stator winding. However, since the generation of the stator winding by means of filling the grooves provided in the stator is often done manually to the required quality and safety of the generator At times, fluctuations in the filling of the respective grooves and in non-optimal utilization of the available joining space in the grooves occur.

Thus, it is considered an object of the present invention to address at least one of the above problems. In particular, the efficiency of the synchronous generator should be improved.

The invention solves the underlying task in a synchronous generator of the type described by this is formed according to claim 1. In particular, a synchronous generator, in particular a much pol iger synchronous ring generator of a gearless wind turbine, proposed for generating electric current, with a rotor and a Stator, wherein the stator has a plurality of grooves for receiving a stator winding in the form of conductor bundles, wherein the grooves each have a groove bottom, the surface is profiled such that when filling a first, groove base layer conductor bundle occupies a predetermined orientation by the profile.

By "multi-pole" in a synchronous ring generator of a gearless wind turbine is meant a plurality of stator poles, in particular a training with at least 48 stator teeth, often even significantly more stator teeth such as 96 stator teeth or even more stator teeth. The magnetically active region of the generator, namely both the rotor, which can also be referred to as a rotor, and the stator is arranged in an annular region about the axis of rotation of the synchronous generator. In particular, a range of 0 to at least 50 percent of the radius of the air gap is free of materials that carry electrical current or electric field of the synchronous generator. In particular, this interior is completely free and basically accessible. Frequently, this range is also more than 0 to 50 percent of the air gap radius, in particular up to 0 to 70 percent or even 0 to 80 percent of the air gap radius. Depending on the structure, a support structure may be present in this inner region, but in some embodiments it may be formed axially offset. For functional reasons, such synchronous generators of a gearless wind turbine are slowly rotating generators. Under slowly rotating here is understood depending on the size of the system, a speed of less than 40 revolutions per minute, in particular from about 4 to 35 revolutions per minute. The invention is based on the recognition that poor space utilization within a slot of the stator occurs when the lowest-lying layers in the groove, that is, closest to the groove base, are routed irregularly. This leads to an uneven distribution of the conductor bundle included and thus inevitably to the formation of unused spaces. This is where the invention starts, in that a starting profile for the filling with conductor bundles is specified on the groove base by means of profiling. Due to the profiling of the groove bottom, the conductor bundles, which are first filled in the groove, are placed in a predetermined orientation. According to the invention, this first layer then forms, as it were, a follow-up profile for the second layer of conductor bundles to be filled into the groove by means of the already pre-oriented conductor bundle. That in turn forms the next following profile for the layer Leiterbündei to be arranged above, and so on. Already by defining an approximate position of the first layer at the groove bottom in this way, the entire structure of the conductor bundles in the groove becomes more uniform. Already due to this uniformity is less likely to form unused spaces, whereby the degree of filling, also referred to as the packing density increases within the groove. According to the invention, it is not important to position the groove-base layer of conductor bundles exactly. As a result of the bundles of conductors inserted in the connection, the respective underlying bundles of conductors are automatically printed in a uniform complaint - and occupy a corresponding position between the already laid bundles of conductors. Thus, the decisive factor is simply that the number of conductor bundles placed there is determined by the profile of the groove base area, and that these are kept at a distance from one another. See in particular the below explained advantageous further education.

According to a first advantageous embodiment of the invention, the profile has one or more projections which project from the groove base, and or one or more recesses, which are embedded in the groove bottom.

Preferably, the profile is adapted to position the nutgrundseitkjen Leiterbündei at a distance A to each other, which is selected so that the maximum number of layers in the first layer Baren Leiterbündei is reduced compared to an unprofiled groove bottom It may initially seem counterproductive, not so to pack many letter bundles as possible into the bottom side bottom layer. In fact, it has been found within the scope of the invention that it is straight Such limitation is also advantageous, which leads to a uniform formation of the letter bundle structure in the groove. In a preferred embodiment, a distance A 'between adjacent projections or between adjacent recesses is substantially equal to the distance A between the respective adjacent conductor bundles within a layer of letter bundles. In the context of the invention, the term distance means the center distance, that is to say the distance from center to center of a respective conductor bundle or from center to center of a respective projection or a respective recess. In a further preferred embodiment, the distance A 'between adjacent projections and or adjacent recesses depending on the diameter d of the conductor bundles is selected such that each conductor bundle of a second layer stacked on the first layer bears against two adjacent conductor bundles from the underlying first layer.

Preferably, the distance A 'or A is in a range of 1.5 times to 1.85 times the conductor bundle diameter d.

Particularly preferably, the distance A or A 'is in a range from 1.7 times to 1.75 times the conductor bundle diameter d. Particularly preferably, the distance A or A 'is the - times the conductor bundle diameter d. In a further preferred embodiment, the grooves each extend from one revolution! surface of the stator inwards and have a constant groove width B on. Thus, in particular, they have two parallel groove walls which extend from the circumferential surface towards the groove base. In another preferred embodiment, the groove width B is given by the equation B = d (1 + nC), where d is the letter bundle diameter, n is a positive natural number, and C is a coefficient in the range of 0.85 to 0.95. In other words, the groove width B results as the sum of the conductor bundle diameter and a product of the letter bundle diameter d and the coefficient C, or an integer positive multiple of this product. In particular, "n" is one Less than the number of conductor bundles, the two adjacent layers, for example, the first, the groove bottom closest layer and the subsequent second layer can be sorted. At n = 7, for example, results in a groove width B, are arranged in the four each Leiterbündel in adjacent layers. At n = 8, there is a width at which five conductor bundles in one and four letter bundles in the adjacent layer alternately can be inserted into the groove. For other odd and even numbers for n, this will behave accordingly. In a preferred embodiment, C is in the range of 0.86 to 0.87. Particularly preferred is.

In a further preferred embodiment, the projections of the profile have a height h above the groove base, which is in each case at most half of the conductor bundle diameter D. Alternatively or additionally, the recesses of the profile have a depth into the groove base, which is in each case at most half of the conductor bundle By limiting the height or depth of the profile relative to the groove base prevents the conductor bundles of the second layer, which is placed on the nutgrundseiüge layer conductor bundles, in unwoll catfish exclusively on the projections or the areas between two adjacent recesses to the plant but not in contact with the adjacent bundles of conductors, which in turn avoids some risk of uneven development. In a preferred embodiment, the projections and or recesses on the groove bottom towards beveled side surfaces. This facilitates the filling of the groove with the nutgrundseltigen, first layer of conductor bundles. The inserted conductor bundles can slide along the oblique to the groove bottom and are brought in this way faster in their intended position

A variety of features of the synchronous generator according to the invention is embodied in the stator of this synchronous generator. According to a further aspect, the invention thus proposes a stator of a synchronous generator, in particular a multipole synchronous ring generator of a gearless wind turbine, wherein the stator has a plurality of grooves for receiving a stator winding in the form of conductor bundles, wherein the grooves each one Have groove base, the surface is profiled so that when filling a first base side layer of conductor bundles assumes a predetermined by the profile orientation In this way, the stator described above solves the problem underlying the synchronous generator according to the invention in the same way. With regard to the advantages of our underlying findings for this aspect of the invention, reference is made to the above statements on the synchronous generator according to the invention.

The stator according to the invention is preferably developed in the same way as the synchronous generator according to the invention, so reference is made to the above-described preferred embodiments of the synchronous generator with respect to preferred embodiments of the stator.

The invention further relates to a wind turbine, in particular a gearless wind turbine, with a synchronous generator. According to the invention, it is proposed that the synchronous generator is designed according to one of the preferred embodiments described above

The invention will be explained in more detail below with reference to preferred embodiments with reference to the accompanying figures. Hereby show:

1 shows a wind turbine schematically in a perspective view

FIG. 2 shows a gondola of the wind power plant according to FIG. 1 schematically in a perspective sectional view,

FIG. 3 simplifies a schematic perspective view of a stator of FIG

Wind turbine according to FIGS. 1 and 2,

Figure 4a is a schematic cross-sectional view of a groove in a stator according to the prior art, and

Figure 4b is a schematic cross-sectional view of a groove of an inventive

Stators of a synchronous generator according to the invention. Hereinafter, identical reference numerals may indicate similar but not identical elements. In addition, the same elements may be shown in different scales.

Figure 1 shows a wind turbine 100 with a tower 102 and a nacelle 104. On the nacelle 104, a rotor 106 with three rotor blades 108 and a spinner 110 is arranged The rotor 106 is in Betri eb by the wind in a rotational movement and thereby drives a Generator 1 (Figure 2) in the nacelle 104 at.

The nacelle 104 is shown in FIG. The nacelle 104 is rotatably mounted on the tower 102 and driven by an azimuth drive 7 in a generally known manner. In a further generally known manner, a machine carrier 9, which holds a synchronous generator 1, is arranged in the nacelle 104. The synchronous generator 1 is formed according to the present invention and is in particular a slow-rotating, multi-pole synchronous ring generator. The synchronous generator 1 has a stator 3 and an internal rotor 5, also referred to as a rotor. The rotor or rotor 5 is connected to a rotor hub 13, which transmits the rotational movement of the rotor blades 108 caused by the wind to the synchronous generator 1.

Figure 3 shows the stator 3 in isolation. The stator 3 has a stator ring 16 with an inner circumferential surface 18. The inner circumferential surface is bounded by a first end face 14 and a second end face 16 opposite the first end face 14. A plurality of grooves 17 are provided in the inner circumferential surface 18, which are provided for receiving the stator winding in the form of conductor bundles 25, 27, 29 (FIG. 4b) ) are formed. The structural design of the grooves 17 is shown in FIG. 4b. The grooves 17 extend between the first end face 14 and the second end face 16 and are aligned parallel to a longitudinal axis A. The longitudinal axis A is the axis of rotation of the rotor 5 in the generator 1.

The configuration of the grooves 17 will be discussed below in particular also with comparative consideration to a non-inventive, non-profiled groove N according to Figure 4a. In the groove N according to FIG. 4a, it can be clearly seen that a multiplicity of conductor bundles L In essentially disordered arrangement is filled into the groove N. This results in regions with a low packing density, for example the regions B ₁ and B ₂ . Overall, therefore, in the groove N according to Figure 4a, only a suboptimal filling is done In contrast, Figure 4b shows a groove 17 of a stator 3 according to the invention or synchronous generator 1. The groove 17 has a groove width B. The groove is bounded laterally by two parallel side walls 19 a, b, which extend from the circulation surface 18 (FIG. 3) to a groove bottom 21. On the surface of the groove bottom 21 a plurality of, in the present example, four, inwardly projecting VorsprQnge 23 are formed, each having a height h with respect to the groove bottom 21. The protrusions 23 are arranged at a distance of A 'from each other. Due to the arrangement of the projections, a first, base-side layer 25 of conductor bundles L is arranged in the groove 17 at the bottom. The LeiterbOndel of the first layer 25 are arranged to each other at a distance A, due to the projections 23. Preferably, the distance A corresponds to the distance A 'of the VorsprQnge each other, in each case the distances of the center points are considered to each other.

Due to the predetermined by the projections 23 orientation of the conductor bundles L of the first layer 25 are in continuous filling conductor bundles L in a second layer 27 respectively inserted into the groove that they in the gaps or .Tälern "between two adjacent conductor bundles L of the first layer A uniform spacing of the projections 23 relative to each other thus results not only in a uniform spacing of the conductor bundles L of the first layer 25 but also a uniform spacing of the conductor bundles L of the second layer 27. This is successively continued for a third layer 29 of conductor bundles and further layers In the illustrated embodiment, the height h is less than or equal to half the letter bundle diameter d. The distance A between two adjacent conductor bundles is in a range of 1.5 times to 1.85 times the conductor bundle diameter d ,

As can be seen directly from FIG. 4b, the center points of all the conductor bundles in the drawn cross-sectional view fit into a uniform grid so that each conductor bundle, with the exception of the conductor bundles arranged at the edges of the groove 17-side walls 19a, b and groove base 21-are six closest Neighbors, ideally with three nearest bundles of wires each an equilateral triangle span each other. This achieves an optimized filling or packing density in comparison with the illustration according to FIG. 4a. Particularly preferred are the Projections 23 formed of the same material as the conductor bundles L, whereby the space occupied by the projections 23 can still be used.

Each sub-layer of the second layer 27 and each subsequent layer 29 is preferably located at two points of contact on respectively underlying letter bundles. In some cases, the conductor bundles L of the second layer 27 may also come into contact with the projections 23, although due to the limited height h of the projections 23, the formation of an irregularity is restricted.

The width B of the groove 17 according to FIG. 4b in the present case is .d (1 + 7C), where C is in the range from 0.85 to 0.95.

Claims

Claims 1. Synchronous generator (1), in particular a lot of pole synchronous ring generator of a gearless wind turbine (100), for generating electrical power, with a rotor (4) and a stator (3), wherein the stator (3) has a plurality of grooves (17) for receiving a stator winding in the form of Lerterbündeln (L),

wherein the grooves each have a groove bottom (21), the surface of which is profiled such that when filling a first, groove base layer (25) conductor bundle assumes a predetermined by the profile orientation.

2. Synchronous generator according to claim 1,

wherein the profile has one or more projections (23) projecting from the groove base and or one or more recesses embedded in the groove base.

3. Synchronous generator according to claim 2,

wherein the profile is adapted to the nutgrundseitigen conductor bundles at a distance (A) to each other to position, which is selected so that the number of the maximum can be arranged in the first layer conductor bundle is reduced compared to an unprofiled groove bottom.

4. Synchronous generator according to claim 3,

wherein a distance (Α ') respectively adjacent projections and or a distance of each adjacent recesses is substantially equal to the distance (A).

5. Synchronous generator according to claim 3 or 4,

wherein the distance (Α ') between adjacent projections and / or adjacent recesses in dependence on a diameter (d) of the conductor bundles is selected such that each conductor bundle of a second layer (27) stacked on the first layer (25) on two adjacent conductor bundles the underlying first layer is present.

6. Synchronous generator according to one of claims 3 to 5,

wherein the distance (A) is in a range of 1.5 to 1, 5 5 times the conductor bundle diameter (d).

7. synchronous generator according to claim 3 to 6,

wherein the distance (A) is in a range of 1.7 to 1.75 times the conductor bundle diameter (d).

8. synchronous generator according to claim 3 to 7,

wherein the distance (A) is the - fold of the conductor bundle diameter (d).

9. Synchronous generator according to one of the preceding claims,

wherein the grooves (17) each extend inwardly from a circumferential surface (18) of the stator, and each have a, preferably constant, groove width (B).

10. Synchronous generator according to claim 9,

wherein the groove width (B) partially or completely from the equation

B = d (i + n.C)

yields, where

d the LefterbQndeldurchmesser,

n is a positive natural number, and

C is a coefficient in the range of 0.85 to 0.95.

11. Synchronous generator according to claim 9,

where C is in the range of 0.86 to 0.87.

12. Synchronous generator according to claim 10 or 11, wherein is.

13. Synchronous generator according to one of the preceding claims,

wherein the projections (23) have a height (h) above the groove base (21) and / or the recesses of the profile have a depth into the groove base which amounts to at most half of the conductor diameter (d). 14. Synchronous generator according to one of the preceding claims,

wherein the projections (23) and / or recesses to the groove base (21) have beveled side surfaces. 15 stator (3) of a synchronous generator (1), in particular a multi-pole synchronous ring generator of a gearless wind turbine (100), wherein the stator has a plurality of grooves (17) for receiving a stator winding in the form of Lelterbündeln (L),

wherein the grooves each have a groove base (21) whose surface is profiled such that upon filling a first groove base layer (25) conductor bundle occupies a predetermined orientation by the profile 16. Wind turbine (100), in particular gearless wind turbine, with a synchronous generator ( 1) according to any one of claims 1 to 14.