EP3097627A2

EP3097627A2 - Synchronous generator in a gearless wind turbine

Info

Publication number: EP3097627A2
Application number: EP14820778.0A
Authority: EP
Inventors: Volker Diedrichs
Original assignee: Wobben Properties GmbH
Current assignee: Wobben Properties GmbH
Priority date: 2014-01-20
Filing date: 2014-12-11
Publication date: 2016-11-30
Also published as: CL2016001816A1; AR099131A1; SG11201605830QA; CN106415996B; KR20160111475A; DE102014200947A1; CN106415996A; BR112016016564A2; US20160336834A1; MX358154B; MX2016009202A; JP6291597B2; AU2014377432B2; AU2014377432A1; CA2936261A1; WO2015106891A2; ZA201604562B; KR101879112B1; RU2643778C1; WO2015106891A3

Abstract

The invention relates to a synchronous generator (1), in particular a multi-pole synchronous ring generator (1) in a gearless wind turbine (101), for generating electricity, comprising a rotor (4) and a stator (6) with teeth (8) and intermediate grooves (10) for accommodating a stator winding, the stator (6) being subdivided, in the circumferential direction, into stator segments (31-34) that have a plurality of teeth (8) and grooves (10), at least two stator segments (31-34) being offset or staggered relative to one another in the circumferential direction.

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. Moreover, the present invention relates to a sheet set for producing a stator lamination stack of a stator of such a synchronous generator and to a corresponding method for producing such a stator lamination stack. Moreover, the present invention relates to a wind turbine with a synchronous generator.

Wind turbines are well known and generate electric power from wind by means of a generator. Modern gearless wind turbines often have a multi-pole synchronous ring generator with a large air gap diameter. The diameter of the air gap is at least 4 meters and usually extends to almost 5 meters. Composite synchronous generators may even have an air gap diameter of about 10 meters.

During operation of the wind energy plant, ie the respective synchronous generator, noises are generated which can also find large resonance bodies due to the large design, such as, for example, the nacelle lining of a nacelle enclosing the synchronous generator or at least partially enclosing it. For functional reasons, such synchronous generators of a gearless wind turbine are very slow rotating generators that rotate at a typical speed of about 5 to 35 revolutions per minute. This slow speed can also produce special noises, especially when compared to generators that rotate at 1,500 or 3,000 revolutions per minute.

Such synchronous generators gearless wind turbines and thus the wind turbines can be due to their continuous operation to a permanent, disturbing noise source. Nowadays, particularly large, modern wind turbines are increasingly being set up and operated at a greater distance from settlements, so that any noise from the wind turbine is less disturbing. By setting up with a greater distance but the actual problem of noise is not fundamentally resolved, but basically only relocated.

It is therefore an object of the present invention to address at least one of the above-mentioned problems. In particular, the noise development of a synchronous generator described above should be reduced. At least an alternative solution to known solutions should be proposed.

The German Patent and Trademark Office has in the priority application for the present PCT application the following state of the art research: US 6 321 439 B1, DE 10 2009 015 044 A1, WO 201 1/128 095 A2, DE 103 40 1 14 A1, DE 10 2005 061 892 A1, US 2004/0 036 374 A1, DE 199 23 925 A1, DE 101 10 466 A1, US Pat. No. 4,315,171 A and DE 15 38 772 B2

According to the invention, a synchronous generator according to claim 1 is proposed, in particular a multi-pole synchronous ring generator of a gearless wind turbine. Such a multi-pole synchronous ring generator of a gearless wind turbine has a plurality of stator poles, in particular at least 48 stator teeth, often even significantly more stator teeth, in particular 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 around 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.

The synchronous generator thus has a rotor and a stator. The rotor is sometimes referred to as a runner in order to achieve a distinction to the aerodynamic rotor of the wind turbine linguistically. The stator is provided with teeth and grooves therebetween. The grooves receive a stator winding, or a plurality of stator windings, so that the stator winding is thus arranged through the slots and around the teeth. The stator is divided in the circumferential direction in stator segments, each having a plurality of teeth and a plurality of grooves and at least two stator segments are circumferentially offset from each other or entangled. All the stator segments are arranged in the circumferential direction next to each other and moreover, in particular about a quarter of a quarter, or another amount, interlocked or offset, namely such that grooves and teeth of a stator alternately uniformly in the circumferential direction and this uniformity in the transition to the next adjacent stator segment is interrupted by there is a wider or narrower groove, a wider or narrower tooth, or an additional - possibly narrower - tooth or an additional - possibly narrower - groove is arranged, or a tooth is omitted. The transition can basically also be realized differently. On this next, adjacent stator segment then grooves and teeth alternate again evenly, in particular with the same slot width and respectively the same tooth width. In this way, it is now achieved that in the circumferential direction completely uniformly distributed rotor or rotor poles do not reach the teeth or grooves of the staggered or staggered stator segments exactly at the same time, but rather around this offset or this entanglement rather or later , Thus, while a rotor pole reaches a stator tooth of a stator segment, a corresponding rotor pole reaches a stator tooth of another, staggered or staggered stator segment slightly out of time. As a consequence, easily oscillated, in particular sinusoidal, currents are generated in these mutually entangled or staggered stator segments. This, in turn, causes these currents to produce reduced harmonics when superposed in amplitude. Similarly, an immediate superposition of noises with the same frequency but different phase can lead to an overall reduction of the noise, in particular the noise level. These two effects described can also work together, so that synergy effects can be exploited, which can lead to an overall strong noise reduction. For example, the stator can be subdivided into four stator segments 1 to 4 and each stator segment, which is also only given by way of example, each have 12 stator teeth, so that the stator comprises a total of 48 teeth and to that extent would be a comparatively small multi-pole synchronous ring generator of a gearless wind energy plant. The first and third stator segment and thus the grooves and teeth of these two Stator segments would be compared to the second and fourth stator segment, ie offset or crossed their grooves or teeth.

Preferably, at least one tooth forms a stator pole and correspondingly two stator poles form a pole pair, which is used here in a simplified way for stator pole pair. In principle, a stator pole could also be formed from a plurality of teeth or a split tooth, which is not important here. In any case, it is proposed for this embodiment that the number of pole pairs of each stator segment is a multiple of two. In particular, the number of pole pairs of each stator segment is a multiple of six. Such an embodiment, namely that the number of pole pairs of each stator segment is at least a multiple of two, makes it possible to provide partial windings for each stator segment. Thus, each stator segment can be designed as a permanent generator or independent virtual generator, which only shares the rotor with the other stator segments.

If the number of pole pairs of each segment is a multiple of six, a described stand-alone stator segment can be provided with three-phase windings, in particular even with two independent three-phase windings. Both three-phase windings can accordingly generate a three-phase current signal and the three-phase current signals of these two independent three-phase windings can be shifted from each other. This improves downstream rectification. The current signal can also simply be called current.

Preferably, four stator segments are provided and the stator segments are grouped into two segment groups, each with two stator segments. For this purpose, it is proposed that the number of pole pairs of each segment group is a multiple of four. This makes it possible to independently wind each stator segment as described above and at the same time to provide the stator segments basically symmetrically, so that therefore all the stator segments are the same size, in simple terms, ie occupy respectively a quarter circle. Insofar as a tooth has been omitted in the transition between two adjacent and mutually entangled stator segments, this (omitted) tooth must nevertheless be counted. In other words, there would be a stator pole without a separate tooth or a stator pole pair with only one own tooth. The effect of the pole pair is still given by the corresponding winding section, the one tooth and one or more other teeth. Alternatively, if the number of pole pairs of each segment group is not a multiple of four, it is proposed that the stator segments of a segment group have different numbers of pole pairs. For example. For example, a stator with a total of 84 pole pairs, that is 168 teeth in particular, can be divided into two segment groups with two stator segments each. The stator segments of these two segment groups alternate. Thus, each segment group has two stator segments and each segment group has 42 pole pairs and, for example, a stator segment with 24 pole pairs and a stator segment with 18 pole pairs.

For these or other embodiments, it is proposed that each segment group is in each case connected to a rectifier designed as a B12 bridge. In this case, each segment group can be wound in such a way that it generates two three-phase systems as output current. These two three-phase systems, which thus result in six different phase currents, are rectified by means of this B12 bridge. Each phase is thus fed to a branch of this B12 bridge, which rectifies this phase in a known manner with two diodes. The rectified current of each of these phases is applied to a common DC link or other DC memory or DC memory.

Since both segment groups are connected to a B12 bridge and both segment groups generate two three-phase currents which are rectified, a rectified overall signal with very few harmonics can be achieved. This is achieved in particular by virtue of the fact that at least two stator segments or two segment groups are offset or interlocked in the circumferential direction. As a result, the six phases of one segment group are again shifted relative to the six phases of the other segment group in such a way that their superimposition in the rectified overall signal is reduced and thus leads to the lowest possible harmonics.

Preferably, grooves and teeth of a respective stator are arranged equidistantly and the at least two stator segments in the circumferential direction offset or interlocked so that adjacent teeth of the adjacent stator segments or adjacent grooves of the adjacent stator segments have a different distance from each other, as adjacent teeth or grooves of the same stator segment , The grooves and teeth are thus arranged equidistantly in each case within their stator segment, in particular in such a way that all the grooves of a stator segment and in particular of the entire stator have the same width, that is to say extent in the circumferential direction. except for grooves in the transition or contact area of two adjacent stator segments. Accordingly, all the teeth of a stator segment or even of the entire stator have the same width, that is to say extent in the circumferential direction, except for teeth in the transitional or contact region between two adjacent stator segments. The proposed embodiment of the stator thus corresponds to a stator with completely uniform teeth and grooves in the circumferential direction, this stator is divided into stator segments, in particular an even number equal stator segments and then every second stator by a proportion of a groove width or tooth width about the axis of rotation of Generators - mentally - would be twisted.

According to one embodiment, a synchronous generator with a stator is proposed in which a first and a second groove of a first stator segment or a first and a second tooth of the first stator segment have a mean distance from each other of n * a. The variable a denotes the mean distance between two adjacent grooves or teeth of the first stator segment. This therefore describes the distance, for example, the center of the first groove to the middle of the second groove or the center of the first tooth to the center of the second tooth. Preferably, this is identical to the average of each spacing of adjacent teeth of the entire stator.

The variable n is the number of groove pitches, that is, a number that is smaller by 1 than the number of grooves between the considered first and second groove and a number smaller by 1 than the number of teeth between the considered first and second grooves second tooth.

The distance between the first and a further groove, wherein the further groove lies on a second stator segment, or the distance of the first tooth to a further tooth, which lies on the second stator segment, is n * a + v or n * av ,

The variable v here denotes the offset or the entanglement between the first and second stator segment. This entanglement is greater than 0, but smaller than the average groove spacing or average tooth spacing a. Whether this offset v is added or subtracted depends on whether the offset or the entanglement in the considered two stator segments is such that they are entangled or offset from one another, then the variable v would be subtracted, or they are offset from each other and in this case the variable v would be added.

By means of this formulaic description, it can therefore be seen that the teeth or grooves of a stator segment are spaced apart by an n-times average distance, whereas the offset v is additionally added once again to the next, staggered or staggered stator segment. Basically, in this respect also in the offset v and the groove spacing a or pitch a to understand a distance along the circumference or an angle relative to the axis of rotation of the generator and thus to understand the center axis of the stator. The offset or the entanglement preferably has a value of 0.4 to 0.6 groove intervals or tooth spacings a. In particular, the offset is about half of such a groove spacing or tooth spacing a. This ensures that the noises and / or currents generated in the respective stator segments to corresponding noises or currents such a phase shift that the total resulting for the synchronous generator noise is minimized. This is achieved in particular by a favorable superposition of the relevant components, which thereby reduce each other.

Preferably, each stator segment takes up a part of the stator winding or stator windings as a winding segment, and winding segments of non-adjacent stator segments are interconnected. As a result, a corresponding electrical connection is provided in addition to the mechanical entanglement or the mechanical offset of the stator segments. This is done in particular so that non-adjacent stator segments, ie in particular every second stator segment are interconnected, ie in particular in a parallel circuit or in a series connection. These stator segments generate in their winding segments a current of the same frequency and phase. The other, arranged between these non-adjacent stator segments stator segments and thus also not adjacent stator segments, so basically a second group of non-adjacent stator segments are also interconnected and produce together a current with the same frequency and phase. Here, there is usually a three-phase current, which also applies to the corresponding first group of non-adjacent stator segments. Preferably, the interconnection takes place in each case as a series connection, so that the winding segments are connected to the next winding segment of the next, not adjacent stator segment can be connected directly there. It can thus be avoided parallel guidance to many lines.

Preferably, the winding segments are mutually connected to a first and a second rectifier. Thus, the winding segments of the first group of non-adjacent stator segments are connected to the first rectifier and the winding segments of the second group of non-adjacent stator segments are connected to the second rectifier. Accordingly, the current of these two groups is rectified in operation with the respective inverter and fed to a DC voltage intermediate circuit, which is preferably common to both inverters. As a result, it can also be achieved that the two inverters receive phase-shifted currents relative to one another and supply them accordingly to the common DC voltage intermediate circuit, as a result of which the harmonics can be reduced there. As a result, harmonics are also reduced here, which in turn can have positive effects on the noise, so this can reduce. Preferably, the stator and / or the stator winding is formed point-symmetrical, in particular point-symmetrical to the axis of rotation of the synchronous generator. Although the entanglement or the offset of the stator segments with each other may have no mirror symmetry in sections, but can achieve a uniform arrangement by the point symmetry, which can also be conveniently called rotational symmetry, so that the noise reduction described by the offset or the entanglement can be achieved, however, the generator can equally smoothly run around.

It is preferably proposed that all the slots of the stator are the same, that is, they are not changed by the offset or the restriction. The offset or the restriction is instead achieved by correspondingly adapted teeth. These can be enlarged or reduced, for example, in the circumferential direction in the contact region of adjacent stator segments. It can also be provided in each case an additional tooth. In this way, in particular, it is also achieved that the line strands of the stator winding can be routed in the same way in all grooves in the usual way.

The synchronous generator is preferably characterized in that the stator winding or the winding segments have phase windings in phases. In each case, such a winding strand is placed through a first groove, so basically led forward, and returned by a second groove. Such laying through these first and second grooves is repeated, at least once, so that at least one loop is laid through these two grooves and thus around the intervening teeth. Preferably, three loops are laid through these two grooves and around the teeth in between, so that four turns are electromagnetically effective. The laying of this winding strand then continues mutatis mutandis in a third and fourth groove.

The phase windings of other phases are mutatis mutandis misplaced. Preferably, three loops are laid through these two grooves and thus around the intervening teeth. This makes it possible to achieve a good ratio between the effort of winding on the one hand and the efficiency of the synchronous generator during operation, on the other hand. In particular, the use of three loops is particularly advantageous for the synchronous generator of a wind turbine, which is operated gearless. Three loops make it possible to continuously lay the respective winding strands for a stator segment. For this purpose, winding strands are necessary, which have a large effective line cross-section, which is composed of a plurality of individual lines, which can nevertheless still be handled during winding. At the same time unnecessarily many winding steps are avoided by a too thin strand and it is avoided to use such a thick strand with even fewer loops, which would make handling very difficult or at least avoids the splitting of a winding strand into two parallel strands.

Preferably, five grooves and six teeth lie between the first and second groove and in the at least one loop. The remaining five slots may be provided for five phase windings for five additional phases. Preferably, a winding strand is continuously wound through a stator segment and in particular continuously through all the stator segments of a segment group. As a result, problems in connection points can be avoided and in the continuous, uninterrupted winding of a winding strand for all stator segments of a segment group, these stator segments can be connected in series according to a simple manner in a simple manner. According to the invention, a sheet set having a plurality of stator laminations is also proposed for assembling into a laminated stator core. This sheet set is preferably designed so that it can produce a laminated stator core of a synchronous generator according to one of the embodiments described above. The stator laminations of this sheet metal set all have several grooves and teeth. The sheet set distinguishes three types of stator laminations, namely a normal sheet, an expanded sheet and a compression sheet. The normal sheet basically corresponds to a conventional, known sheet of a stator of a synchronous generator without offset or entanglement. From a large number of such standard sheets, a stator sheet packet can be assembled. For this purpose, a corresponding number of normal sheets are placed in a circle in a first layer and then a second layer is laid in the same way but offset to the sheets of the first layer, and so on until the laminated stator core is formed by many such staggered sheet metal layers. To achieve a laminated stator core, in which stator segments are provided and staggered or interlocked with each other, however, further metal sheets are required which take this offset or this entanglement into account. For this purpose, the expansion plate and the compression plate are provided. The stretch sheet basically corresponds in type to the normal sheet, but has a stretched area, in particular a widened tooth. This stretched region is thus provided for the transition region of two mutually entangled or staggered stator segments, namely, which are removed from each other according to the offset or the entanglement. This creates this stretched area, which this expansion plate provides.

Accordingly, the compression plate on a compressed area, which is provided for the transition region of two stator segments, which are offset from each other or interlocked.

Preferably, these stretched or compressed areas are not in the middle of the respective stretch sheet or compression plate, but off-center about one third. In addition, these stretch regions or compression regions are mirror-symmetrical, so that their shape thus remains unchanged when the corresponding stretch or compression plate is turned over from an upper side to a lower side or vice versa. Thus, these dunnage and stretch sheets can be stacked in different layers overlapping one another, so that the respective stretch regions or compression areas come to lie exactly above each other, but without the corresponding stretch sheets or upsetting plates come to lie exactly on top of each other. Thus, an overlapping layer formation during production of the laminated core can also be achieved in the region of the stretch regions or compression regions, without having to produce different sheets in each case. The vertical integration therefore requires only a normal sheet, an expanded sheet and a compression plate to include. With these three different types of metal sheets, the entire laminated core can be made, including stretched areas, including the transition areas between staggered or interlocked stator segments, including overlap.

In addition, a method for producing a laminated stator core is proposed, which is based on the production of a laminated stator core with the aid of a sheet metal set according to one of the embodiments described above. It is therefore proposed here that the stator lamination stack is first constructed in a layered manner in the usual way, wherein an expansion plate or an upsetting plate is respectively arranged for the transition regions. For the next layer an expanded sheet or upset plate is provided in the respective area, which is, however, reversed with respect to the respectively underlying sheet, ie with the top down or bottom up. Due to the non-central arrangement of the stretch region or compression area changes its position by turning the sheet and thus it can be achieved with one and the same sheet overlapping, so not completely stacked stacking. According to the invention, a wind turbine with a synchronous generator according to one of the embodiments described above is also proposed.

The invention will now be described by way of example with reference to exemplary embodiments with reference to the accompanying figures.

Fig. 1 shows a wind turbine schematically in a perspective view.

Fig. 2 shows an axial sectional view of a known synchronous generator. Fig. 3 shows schematically a circuit diagram of a known, externally excited synchronous generator with two three-phase windings and diode rectifier downstream.

Fig. 4 shows a synchronous generator according to the invention in an axial sectional view.

show sections of Fig. 4th

Fig. 5A

to 5D show different implementation possibilities of a transitional area than

Embodiments of the detail of FIG. 4a.

Fig. 6 shows schematically a possibility of interconnecting the segments of a

Synchronous generator with downstream rectifier.

7 shows a synchronous generator in an axial sectional view according to a further embodiment with stator segments with different numbers of pole pairs.

Fig. 7A shows a detail of Fig. 7 illustrates a winding diagram of a synchronous generator of an embodiment. illustrates a winding diagram of a synchronous generator of another embodiment.

FIG. 1 shows a wind energy plant 100 with a tower 102 and a nacelle 104. A rotor 106 with three rotor blades 108 and a spinner 110 is arranged on the nacelle 104. The rotor 106 is set in rotation by the wind in rotation and thereby drives a generator in the nacelle 104 at.

FIG. 2 shows a known synchronous generator 201 in an axial sectional view, ie in a view in the direction of the axis of rotation 202, wherein the synchronous generator 201 is cut transversely to the axis of rotation 202. The synchronous generator is designed as an internal rotor The rotor generator 201 is designed as a multi-pole ring generator and has a free interior, which occupies over half of the total diameter or total radius of the synchronous generator 201. By way of example, 168 stator teeth 208 are provided. There are also provided a plurality of stator slots 210 which alternate with and interpose stator teeth 208.

The rotor 204 has a number of rotor poles or pole shoes 212, between each of which grooves 214 with windings are provided. The rotor grooves 214 are provided with windings for exciting the rotor. In operation, the rotor 204 rotates relative to the stator 206 and the rotor poles 212 sweep past the stator poles 208. Between rotor 204 and stator 206, a narrow air gap 216 is present.

FIG. 3 illustrates an interconnection of a known synchronous generator 201 and schematically shows an excitation circuit 220 for exciting the rotor 204 by means of a direct current. Schematically, first and second three-phase stator windings 221 and 222, respectively, are shown. These are connected via a first interconnection 223 or second interconnection 224 via a first or second rectifier 225 or 226 and both rectifiers 225 and 226 feed on a common DC voltage intermediate circuit 228, which is symbolized by a capacitor. FIG. 4 shows a synchronous generator 1 with an axis of rotation 2, a rotor or rotor 4, a stator 6, a plurality of stator teeth 8 and just as many stator slots 10, similar to FIG. 2. The rotor or rotor 4 has rotor poles or pole shoes 12 and in between rotor grooves 14 on. Between the stator 6 and the rotor 4 there is an air gap 16. The rotor or rotor 4 could be identical to the rotor or rotor 204 of FIG. However, according to the invention, the stator 6 differs from the stator 206 of FIG. 2.

In that regard, the stator 6 is divided into four segments 31 to 34. Adjacent segments are mutually entangled or offset. Thus, the first and third segments 31, 33 are not entangled or offset relative to each other, but relative to the second and fourth segments 32, 34, respectively. Likewise, the second and fourth segments 32, 34 are not interleaved or staggered. There is thus a compressed region 36 or extended region 38 between adjacent segments, depending on whether the each adjacent segments to each other or away from each other or are entangled. FIG. 4A indicates a section of the synchronous generator 1, which relates to a compressed region 36. Ways to accomplish this upset portion 36 are shown in FIGS. 5A-5D. FIG. 4B shows a detail of the synchronous generator 1, which includes a stretched region 38.

In FIG. 4B, it can be seen for the stretched region 38 that a widened stator tooth 8 ^{+ is} present, whereas the remaining stator teeth 8 have a smaller, namely normal width, and are also equal to one another.

Accordingly, Figure 4A should have a narrowed tooth 8 ^" or other translation of the compressed area for the swaged area 36, with all the stator slots 10 being the same size and shape, which, however, is only one way of implementation for possibilities of realization, which are shown concretely in FIGS. 5A to 5D.

The enlargements of FIGS. 4B and 5A to 5D show that the teeth 12 and grooves 14 of the rotor or rotor 4 are unaffected by the segmentation and entanglement or sprain of the stator 6.

FIGS. 5A to 5D thus show cutouts according to the detail or placeholder of FIG. 4A, and show different possibilities for the specific embodiment of the compressed region 36, which in FIGS. 5A to 5D correspondingly designates 36A, 36B, 36C or 36D becomes. In this compressed region, the two stator segments 31 and 32 with respect to a conventional arrangement, which, for example. Figure 2 shows, rotated towards each other. This is about the measure of a groove width, wherein in the embodiment shown in FIG 4 and thus also according to the figures 5A to 5D, the groove width corresponds approximately to the width of the web 40 of each tooth 8. Preferably, this rotation of the two adjacent regions corresponds to each other to about half the average tooth spacing or groove spacing, ie a half distance from the tooth center to the center of the next tooth or from the center of a groove to the center of the next adjacent groove.

5A, the embodiment of FIGURE 5A proposes to make the immediately adjacent grooves 10A 'and 10A "narrower and provide a divider 42A therebetween, which divider 42A may be the two Insofar, this separating web 42A can also have an electrically insulating function, the problem being that the grooves 10A 'and 10A "are smaller than the grooves 10 and Thus, it is also possible to accommodate fewer or poorer lines of the stator winding.

As an alternative, therefore, an embodiment according to Figure 5B is proposed, in which in the compression region 36B, two boundary grooves 10B 'and 10B "are provided which have a greater depth than the remaining grooves 10. The boundary grooves 10B' and 10B" are thus slimmer , but formed deeper and can thus take about as many lines or wires than the other grooves 10. The two boundary grooves 10B 'and 10B "are separated by a divider 42B, which may have the same material as the remaining teeth 8 and Laminated core of the stator 6 at all.

Figure 5C shows a very similar embodiment as Figure 5B, but with a divider 42C is provided, which is made of a different material than the stator lamination, so as the other stator teeth 8. The material of the divider 42C is made of highly permeable, at least manufactured in comparison to the stator higher permeable material. For example, so-called mu-metal can be used. By means of this highly permeable material, the reduced cross section of this separating web 42C can be compensated in whole or in part. In contrast to the embodiment according to FIG. 5B, the separating web 42C is not punched out of the corresponding sheet, but can be used after completion of the laminated core of the stator 6, possibly also together with the insertion of leads of the stator winding.

5D shows that the two limit grooves 10D 'and 10D "are now immediately adjacent, without a stator tooth between them.For the separation, a separating web 42D can for example be provided as insulating paper or can be dispensed with altogether.The limit grooves 10D' and 10D" in this case have the same shape as the other grooves 10 and have the same amount and the same size space for receiving lines of the stator winding. When inserting such lines of the stator winding, care should be taken to ensure that the limit grooves 10D ', 10D ", which are as evenly as possible in these two without an intermediate tooth, come to lie.

Figure 6 illustrates the interconnection of the stator windings of a synchronous generator according to the invention schematically according to an embodiment. Here, a synchronous generator with a division of the stator according to Figure 4 is used. There are thus four stator segments 31 to 34 are provided, wherein the first and third segments 31 and 33 are untranslated with each other, but are opposite to the second and fourth segments 32 and 34 entangled. The second and fourth segments 32, 34 are also not entangled with each other or offset. The first and third segments 31, 33 are thus schematically shown as a first region 44 or as a first segment group 44 and accordingly the second and fourth segments 32, 34 are shown schematically as a second region 46 and a second segment group 46, respectively ,

Both segment groups 44 and 46 each carry two three-phase stator windings 51 and 53 or 52 and 54. In each case both stator windings 51 and 53 or 52 and 54 extend through respective segments 31 and 33 or 32 and 34 of the relevant segment group 44 or Within a segment group 44 or 46, the strings of a stator winding 51 to 54 are electrically connected in series, namely by a star point 45 or 47 (only indicated) by a first stator segment 51 or 52, further by a second stator segment 53 and 54 and finally to one of the rectifiers 61 to 64. Thus, two of the stator windings 51 to 54 run through each segment.

In the embodiment shown, each of the four stator windings 51 to 54 is individually connected to a first to fourth rectifier 61 to 64. All four rectifiers 61 to 64 use the same DC intermediate circuit 66, in which they thus all feed together. The DC intermediate circuit is also symbolized by a capacitor 68 and a load resistor 70 symbolically represents further elements to be connected, namely in particular one or more boost converters to be connected and / or one or more inverters to be connected for generating a sinusoidal alternating current to be fed into an electrical supply network.

The rectifiers 61 to 64 shown are each designed as passive, so-called B-6 rectifiers.

Because windings of both the first region 44 and the second region 46 are separately connected to a rectifier or a set of rectifiers, the currents generated differently by the entanglement or the offset with respect to possible harmonics can also be correspondingly supplied separately the respective rectifiers and thus separately fed to the DC voltage intermediate circuit 66 and fed there by the rectification. By the rectification However, the generated alternating currents are rectified, any harmonics or superimposed ripple, however, remain essentially available and can then be present in the DC voltage intermediate circuit, possibly attenuated as a voltage ripple or voltage fluctuations. In this case, the ripples to be assigned to the first region 44 are displaced against the ripples which are to be assigned to the second region 46, being superimposed in the DC intermediate circuit and thus being able to mutually weaken each other. In the optimal, at least theoretical case, the ripples of the first region 44 could compensate with the ripples of the second region 46. In addition, by an additional separate interconnection of the individual segments 31 to 34, the redundancy of the generator, namely in particular of the stator can be increased.

It is thus proposed a multi-pole synchronous ring generator of a wind turbine, which can work in particular to previously known synchronous generators otherwise same rather noise-reduced design.

In particular, a generator is also used with six phases, namely a first and second system with three phases each, and a stator with 12 slots per pole pitch and a diode rectifier. Such a multi-pole synchronous ring generator according to the prior art can produce pulsating torques with harmonic components and the like. 12th order. Such pulsating torques may, for example, assume a frequency of about 120 Hz, which of course depends on the speed, and may be annoying.

To solve it is thus proposed to divide the stator winding or stator windings into segments, in particular in four segments. The grooves of the segments are entangled so that a shift of half a slot pitch between the segments is formed, as shown in Figure 4 with the enlargements 4A and 4B. This results in corresponding winding edge regions, which may be formed as a compressed region 36 or elongated region 38, which alternate over the circumference of the stator. The configuration of these winding edge regions can be made as shown in FIGS. 5A to 5D. Other design options are also not excluded. In addition, it is proposed to connect two non-adjacent segments, namely to one area. Typically, this interconnection can be done by series connection. The interconnection relates in each case to two three-phase winding strands. Each interconnected area thus consists of two three-phase winding strands. Preferably, each region is switched with a 12-pulse diode rectification circuit and a DC side parallel circuit.

The proposed solution was particularly explained using the example of dividing a stator into four segments. However, other subdivisions may also be made, in the simplest case a subdivision into two segments, in which case each individual segment also forms an area in the sense of the first or second area 44, 46. Likewise, a subdivision into significantly more than four segments, preferably in an even number of segments can be made.

FIG. 7 shows in a sectional view a synchronous generator 701 with a stator 706 with four stator segments or segments 731 to 734. The stator segments 731 and 733 form a first segment group and the stator segments 732 and 734 form a second segment group. Each of these segment groups 731, 733 and 732, 734 has 42 pole pairs and thus a number of pole pairs which is not a multiple of four. Accordingly, the stator segments of a segment group have different numbers of pole pairs, namely the first stator segment 731 has 24 pole pairs and the second stator segment 733 has 18 pole pairs. Accordingly, of the second segment group, the stator segment 732 has 24 pole pairs, and from the same segment group, the stator segment 734 has 18 pole pairs. Thus, each of these four stator segments 731 to 734 has a multiple of six as the number of pole pairs, or in other words, the number of pole pairs of each of the stator segments 731 to 734 is divisible by the number six without remainder.

Incidentally, in FIG. 7, the stator slots are identified by the reference numeral 710 and the stator teeth by the reference numeral 708. The rotor 4 may correspond to the rotor 4 of FIG. 4, and to this end, reference will also be made to its further description for the explanation of FIG. 4. The separation between the individual stator segments 731 to 734 is indicated by corresponding dividing lines 735. Compared to the embodiment of FIG. 4, this results in a displacement of the stretched region 738, which likewise has a widened stator tooth 708 ⁺ . This stretched area 738 with the widespread The tooth 708 ⁺ is arranged in the cutout B of FIG. 7, which is shown enlarged in FIG. 7A. Apart from the displacement of this stretched region 738 or widened tooth 708 ⁺ , the remaining descriptions regarding the embodiment according to FIG. 4 and the enlarged illustration of FIG. 4B also apply mutatis mutandis to the embodiment of FIGS. 7 and 7A.

The compressed area 736 is basically unchanged and is also located in the marking A according to FIG. 7. For this marking A, various variants are also possible, as described in FIGS. 5A to 5D. In that regard, reference is made to these figures 5A to 5D. FIG. 8 illustrates the winding scheme for a synchronous generator according to an embodiment for a stator segment, such as the stator segment 733 of FIG. 7 with 18 pole pairs. This stator segment, which bears the reference numeral 833 in FIG. 8, is shown in FIG. 8 as a stretched element without curvature, thereby simplifying the illustration of the winding diagram. FIG. 8 shows a plan view of corresponding teeth 808 and grooves 810 according to FIG. 8A, a side view of the stator segment 3 according to FIG. 8B, a side view of a likewise linearly illustrated part of the rotor 804 according to FIG. 8C, the illustration also being schematic here without curvature, and a plan view of the rotor teeth or pole pieces of the rotor 804 according to the representation D. The view 8A of Figure 8 illustrates the winding scheme basically from the left beginning with the winding strand 850, which is laid through a first groove 851, ie Basically in a forward direction, and is returned by a second groove 852. This winding strand 850 is then guided to the first groove 851 and placed there again a second time and returned through the second groove 852 again. This is repeated two more times so that the winding string 850 is then placed around six teeth 808 in three complete loops 858. However, four windings are electromagnetically effective because the initially incoming winding strand, which comes from the left according to FIG. 8, 8A, finally with the part of the winding strand 850 which leaves the second groove 852 to the right, after at least the stator segment 833 shown is completely wound, electrically connected.

After the winding strand 850 has been returned for the fourth time through the second groove 852, it is now inserted into a third groove 853 and returned through a fourth groove 854 and this is repeated until again three loops or four electrified yield magnetically effective turns. This is repeated again in a fifth and sixth groove 855 and 856, respectively, until the winding strand 850 according to FIG. 8, view 8A has arrived at the right side. From there, the winding strand 850 can be fed to a further stator segment, or be connected to an output in order to provide a current to be generated there.

The view 8B schematically shows all of the teeth 808 and grooves 810 of the stator segment 833. To illustrate, the grooves 810 are labeled A through F, with one letter representing a phase winding phase. The winding illustrated in view 8A in this case relates to the strand for the phase marked with the letter D. Each D + denotes a return of the winding strand 850. The remaining letters A to C and E and F are provided with corresponding symbols, ie "+" for the Hinführt and "-" for the recycling.

The view 8B of FIG. 8 also shows that the winding strand is provided in each case in four layers in each stator slot 810. Incidentally, the view 8 B also indicates that a corresponding winding is provided in each case for the remaining phases A to C, E and F, as is the view for only one phase, which illustrates phase D.

The view 8C shows from the rotor 804 a cutout with six pole shoes 860, each having an alternating sense of direction, to generate a DC magnetic field in the excitation strands 862 each with a reverse direction with respect to the respective adjacent pole piece upon DC excitation. Each pole piece 860 has a pole piece head 864 which is approximately arrow-shaped, as shown in the view 8D. The direction of movement of the rotor 804 is directed in the direction of the movement arrow 866 as intended. Two pole shoes 860 and thus two rotor poles, that is to say a rotor pole pair, extend in total over 12 stator teeth 808 or 12 stator slots 810 and thus over six stator pole pairs.

FIG. 9 shows or illustrates a winding diagram for a twelve-phase twelve-phase synchronous generator in a very similar representation to FIG. 8. The underlying synchronous generator has four segments 931 to 934. The first and third segments 931 and 933 form a first segment group and the second and fourth segments 932 and 934 form a second segment group. Each of these two segment groups has two three-phase windings, ie six windings each. For illustration, but only one winding or only one winding strand 950 and 980, respectively. FIG. 9 likewise shows four views in the sense of the views 8A to 8D, namely correspondingly as views 9A to 9D. However, only the representation 9A represents a continuous winding strand 950 or 980.

For the first segment group consisting of the first and third segments 931 and 933, the winding strand 950 begins at a common star point 995. The winding strand 950 is part of a three-phase winding with two further, not shown in FIG 9 winding strands. These three winding strands thus form a three-phase system and are connected to each other at the star point 995. From this star point 995 of the winding strand 950 is first passed through a first groove 951 and returned by a second groove 952 and laid by these two grooves 951, 952 in three loops 958 and thus four electromagnetically effective turns. Subsequently, this winding strand 950 is led further to the first segment 931 and laid there through a third groove 953 and returned through a fourth groove 954 until three loops have formed. The winding strand then continues in a fifth groove 955 and is repeatedly fed back through a sixth groove 956 to form three loops. Finally, the plot for the winding string 950 ends at a connection point 996. From this connection point, the winding string 950 or another connected electrical line is fed to a rectifier such as the B-6 rectifier 61 according to FIG. 6, namely a branch with two diodes , In the same way, the remaining grooves are provided with the remaining five strands of these two three-phase systems, so that all the grooves of this first segment group of the first and second segments 931 and 933 are then filled.

Analogously, a winding of the second and fourth segments 932 and 934 of the second segment group takes place with the winding strand 980. This winding is wound from the common star point 998 via a first to sixth groove 981 to 986 with corresponding loops 988 and ends at the connection point 999 for connection to a rectifier.

The synchronous generator according to FIG. 9 has a first and a second segment group, each having 18 pole pairs. Thus, four stator segments 931 to 934 are provided, which are each grouped into two segment groups 931 and 933 as well as 932 and 934. Each segment group thus does not have a number of pole pairs, which is a multiple of four, and thus the stator segments of a segment group have different numbers of pole pairs, namely the respective larger stator segment 931 or 932 twelve pole pairs and the respective smaller stator segment 933 or 934 six pole pairs. It should be noted that the intended entanglement for the simplified representation of the winding scheme has not been shown in FIG. Figure 9 is intended to illustrate the winding scheme.

Claims

claims

Synchronous generator (1), in particular multi-pole synchronous ring generator (1) of a gearless wind turbine (101), for generating electric current, comprising

a rotor (4) and

a stator (6) with teeth (8) and interposed grooves (10) for receiving a stator winding, wherein

the stator (6) is circumferentially divided into stator segments (31-34) each having a plurality of teeth (8) and grooves (10) and at least two stator segments (31-34) offset or interlocked in the circumferential direction.

Synchronous generator (1) according to claim 1,

characterized in that

at least one tooth (8) forms a stator pole and two stator poles form a pole pair and the number of pole pairs of each stator segment (31-34) is a multiple of two, in particular a multiple of six.

Synchronous generator (1) according to claim 1 or 2,

characterized in that

four stator segments (31-34) are provided and the stator segments (31-34) are grouped into two segment groups (31, 33, 32, 34), the number of pole pairs of each segment group (31, 33; 32, 34) being a multiple of is four, or the stator segments (31-34) of a segment group (31, 33; 32, 34) have different numbers of pole pairs.

Synchronous generator (1) according to one of the preceding claims,

characterized in that

Grooves (10) and teeth (8) each of a stator segment (31-34) are arranged equidistantly and

the at least two stator segments (31-34) are offset or interlocked in the circumferential direction so that adjacent teeth (8) of the adjacent stator segments (31-34) or adjacent slots (10) of the adjacent stator segments (31-34) are at a different distance from one another have as adjacent teeth (8) and grooves (10) of the same stator segment (31-34). Synchronous generator (1) according to one of the preceding claims,

characterized in that

a first and a second groove (10) of a first stator segment (31) or a first and a second tooth (8) of the first stator segment (31) have a mean distance from each other of n * a, wherein

a is a mean distance between two adjacent grooves (10) and teeth (8) of the first stator segment (31) and

n is the number of grooves (10) between the first and second grooves (10) and teeth (8) lying between the first and second teeth (8) is less than one, and wherein

the first groove (10) to a further groove (10) which lies on a second stator segment (32), or

the first tooth (8) to a further tooth (8) located on the second stator segment (32) is an average distance of n * a + v or n * av, where v is the offset between the first and the second stator segment (31, 32) and is both greater than 0 and less than a.

Synchronous generator (1) according to one of the preceding claims,

characterized in that

the offset or entanglement (v) has a value in the range from 0.2 * a to 0.3 * a, in particular 0.25a.

Synchronous generator (1) according to one of the preceding claims,

characterized in that

each stator segment (31-34) accommodates part of the stator winding as a winding segment (51-54) and winding segments (51, 53; 52, 54) of non-adjacent stator segments (31, 33; 32, 34), in particular a segment group (31, 33 32, 34) are interconnected and / or the winding segments (51-54) are mutually connected to a first and a second rectifier (61-64), both rectifiers preferably feeding on a common DC voltage intermediate circuit, in particular each segment group ( 31, 33, 32, 34) are each connected to a rectifier formed as a B12 bridge.

Synchronous generator (1) according to one of the preceding claims,

characterized in that Winding segments (51, 53, 52, 54) of non-adjacent stator segments (31, 33, 32, 34) are electrically connected in series with each other.

Synchronous generator (1) according to one of the preceding claims,

characterized in that

the stator winding or the winding segments have phase windings (850) in phases,

a winding strand (850) is laid in a first stator segment (31) through a first groove (851) and returned through a second groove (852), the laying through these first and second grooves (851, 852) is repeated, in particular so, that at least one, in particular three loops through these two grooves (851, 852) and thus placed around the intervening teeth (8), so that there is an electromagnetically effective number of turns of four, and

the laying of this winding strand (850) then continues in this sense in a third and fourth groove (853,854) and possibly in corresponding further grooves (855,856) until the winding strand (850) led to a first groove of another stator segment (833) is, or there is connected to a winding strand of the other stator segment, or is connected to an output.

Synchronous generator (1) according to one of the preceding claims,

characterized in that

lie between the first and second groove (851, 852) and in the at least one loop five grooves (8) and six teeth (10).

Synchronous generator (1) according to one of the preceding claims,

characterized in that

a winding strand (850) is wound continuously through a stator segment (31-34) and / or through all the stator segments (31, 33, 32, 34) of a segment group (31, 33, 32, 34).

Synchronous generator (1) according to one of the preceding claims,

characterized,

that the stator (6) and / or the stator winding is point-symmetrical, in particular to a rotation axis (2) of the synchronous generator (1). Synchronous generator (1) according to one of the preceding claims,

characterized in that

all the grooves (10) of the stator (6) are equal and the offset or the entanglement (v) of the stator segments (31-34) is achieved by correspondingly adapted teeth (8 ⁺ , 8 ^" ), in particular by being enlarged or reduced in the circumferential direction Teeth (8 ⁺ , 8 ^" ) in the contact area of adjacent stator segments (31-34).

Sheet set comprising a plurality of stator laminations for assembling into a stator lamination stack, in particular a synchronous generator (1) according to any one of the preceding claims, wherein each stator lamination has a plurality of groove portions and a plurality of tooth portions for producing grooves (10) and teeth (8), and the lamination set comprises

at least one normal sheet with tooth regions and groove regions for producing identical grooves (10) or teeth (8),

at least one expanded sheet having a stretched region (38)

for producing a circumferentially broadened tooth (8 ⁺ ) or toothed area, or

for producing a circumferentially widened groove or groove region, and

at least one upsetting sheet having a swaged portion (36) for producing a circumferentially narrowed tooth (8) or

Tooth area, or

for producing a circumferentially narrowed groove or groove area.

Sheet set according to claim 14,

characterized in that

each expansion plate has its stretched region (38) off-center in the circumferential direction, in particular approximately in a first or last third, and / or

the stretched region (38) is mirror-symmetrical in the circumferential direction and / or

each edging plate has its compressed area (36) eccentrically in the circumferential direction, in particular approximately in a first or last third and / or

the compressed area (36) is mirror-symmetrical in the circumferential direction.

16. A method of manufacturing a laminated stator core comprising the steps

Producing a first sheet metal layer of standard sheets, expanded sheets and upsetting sheets of a sheet set according to claim 10, wherein the stretch sheets are arranged in areas in which adjoin stator segments with a positive offset, and

the upsets are placed in areas where stator segments adjoin one another with a negative offset

Producing a second sheet metal layer, wherein

Stretch sheets and upsetting plates

be turned in such a way opposite the stretch sheets or upsetting sheets of the first layer that their upper side comes down and their underside comes up and

They are each placed with their stretch region or compression area on each other, whereby a partial overlap of the respective sheets is formed in that the stretch regions or compression regions are arranged eccentrically.

17. Wind energy plant (101) with a synchronous generator (1) according to one of claims 1 to 13.