Multi-part conductor, use, and method for producing the multi-part conductor

Abstract

The invention relates to a multi-part electrical conductor (2, 3, 4, 5) and to a method for producing same, having conductor core regions (20, 30, 40, 50) comprising multiple individual conductors (10) and having conductor strand regions (21, 31, 41), which conductor strand regions (21, 31, 41, 51) are configured to form, by means of a conductor filling region, a predefinable external geometry (h, b) of the multi-part conductor (2, 3, 4, 5). The proposed multi-part conductor (2, 3, 4, 5) accordingly has an external shape which is optimisable with regard to fill factor in the field of application of electric machines. In particular, the external geometry (h, b) can remain the same along the length of the conductor (2, 3, 4, 5) in spite of the multi-core nature and Roebel-bar-type transposing of the individual conductors (10, 12, 13, 14, 15). To this end, use is made in particular of an additive manufacturing process.

Description

[0001] Description

[0002] Multi-element conductor, use and manufacturing process of the multi-element conductor

[0003] The invention relates to a multi-element conductor, a use of the multi-element conductor and a manufacturing method therefor.

[0004] It is known that energy losses occur in a wide variety of electrical applications and electrical products, particularly energy losses associated with electrical current flow, which can be attributed to various physical effects. Examples of such effects are the skin effect or the proximity effect. The skin effect is also referred to as the current displacement effect. This occurs in electrical conductors through which alternating current flows, particularly high-frequency alternating current. The alternating fields penetrating the conductor cause attenuation and, so to speak, displace the current flow from the interior of the conductor to the outer areas. The proximity effect is also based on current attenuation by a penetrating alternating field, but this field originates from a neighboring electrical conductor.

[0005] To avoid such effects and the associated energy losses, or at least minimize them as much as possible, cables with the largest possible surface area have been used, particularly in high-frequency technology. Examples include waveguides, stranded wires, or ribbon cables.

[0006] The so-called Roebel conductor is used particularly in electrical windings, e.g. in large three-phase generators or three-phase motors. This represents a special form of multi-element conductor. It contains several parallel conductors that are insulated from one another and specially layered, twisted or braided. By means of the special arrangement and braiding of the partial conductors, the stray field is changed in such a way that the current density in all parallel conductors is almost constant and a current displacement effect is almost avoidable. However, the production of such conductors is quite complex and is currently only used for very large machines in the high power range of several kilowatts to megawatts.

[0007] A disadvantage of previous Roebel conductors or Roebel-type conductors is that the total cross-sectional area of ​​such an interwoven multi-core conductor is larger than that of a corresponding solid conductor with the same total cross-section. Particularly when using multi-core conductors in electrical machines, the conductor cross-section presents a further technical challenge. The better a slot in an electrical machine is filled by an electrical conductor, especially a strand of electrical sub-conductors, the better its performance. The so-called fill factor is a measure of this ratio of conductor cross-section to slot cross-section.

[0008] To address the challenge of adaptable conductor geometry, initial attempts have been made to produce Roebel-type conductors using additive manufacturing processes. However, current losses in conductors manufactured in this way are not reduced to the same extent as in Roebel conductors manufactured using conventional methods.

[0009] Based on this, the object is to specify an electrical conductor and a production method for an electrical conductor which meets the requirements for a predeterminable external geometry and at the same time has electrical properties that are as good as or better than previous Roebel conductors. This object is solved by the features of independent patent claim 1. The object with regard to the use is solved by the features of claims 11 and 12. The object with regard to a production method is solved by the features of patent claim 13. Advantages and embodiments of the invention, which can be used individually or in combination with one another, are the subject of the dependent claims.

[0010] The multi-element electrical conductor according to the invention has a conductor core region comprising a plurality of individual conductors and a conductor braiding region. In particular, the multi-element electrical conductor according to the invention has a plurality of conductor core regions and conductor braiding regions, which, when arranged alternately in series, form the multi-element electrical conductor. In particular, the multi-element electrical conductor has as many conductor braiding regions as individual conductors.

[0011] The conductor braiding regions of the multi-element conductor according to the invention are designed to form a predeterminable external geometry of the multi-element conductor by means of at least one conductor filling region.

[0012] In particular, this predeterminable outer geometry can be specified by the conductor core regions. Depending on the application of the multi-element electrical conductor, multi-element conductors can also be manufactured with different outer geometries. The advantage of the multi-element conductor according to the invention lies in particular in the fact that a high fill factor can be ensured for use of the conductor in an electrical machine. The individual conductors are expediently arranged insulated from one another in the multi-element conductor.

[0013] Advantageously, the conductor braiding regions of the multi-element electrical conductor according to the invention also have individual conductors in addition to the filler regions. A single conductor is to be understood in particular as a continuous electrical conductor, continuous in the sense of a conductor running through the multi-element conductor from start to end. This has the particular advantage that a certain number of continuous individual conductors ensures a sufficient current flow, in particular the total current flow through the multi-element electrical conductor. In an advantageous embodiment of the invention, the conductor filler region of the multi-element electrical conductor is manufactured additively. In particular, there is a large number of conductor filler regions along the multi-element electrical conductor.This has the advantage that the bulges and indentations on the outer geometry of the multi-element conductor strand caused by the interweaving of the individual conductors are filled in a single additive manufacturing step. In particular, the process for filling the conductor strand starts with the outer individual conductors, or the outer individual conductors or sections of the individual conductors are manufactured additively.

[0014] In a further advantageous embodiment of the multi-element electrical conductor according to the invention, the conductor filling regions comprise individual conductors of reduced height, widened individual conductors and / or shape-adapted individual conductors. This means that a modified shape and / or a modified individual conductor cross-section are used to form the external geometry of the multi-element conductor strand. An individual conductor of reduced height, or an individual conductor section of reduced height, can be produced, for example, by material removal. A widened individual conductor, or widened individual conductor section, can be produced by a drawing or pressing process starting from a continuous individual conductor. Specially shape-adapted individual conductors or shape-adapted individual conductor sections are preferably manufactured additively.

[0015] In particular, the individual conductors present in the conductor filling area or forming the conductor filling area, whether they are individual conductors of reduced height, widened individual conductors, or shaped individual conductors, are each individual conductor sections. The individual conductor sections, each modified in the conductor filling area, can continue to run in the adjacent conductor core areas in their original conductor cross-sectional area and / or conductor cross-sectional shape. In a further advantageous embodiment of the multi-element electrical conductor, the individual conductors comprise copper or are formed from copper.

[0016] In particular, the individual conductors are solid individual conductors, in particular conventionally manufactured conductors, and have a material purity of at least 99.96%, in particular of at least 99.98%, preferably of at least 99.99%. The conductivity of the particularly preferably used electrical individual conductors is at least 5.8 x 10 7 S / m or higher .

[0017] In a further advantageous variant of the invention, the multi-element electrical conductor is designed as a Roebel conductor or the multi-element electrical conductor comprises regions which are designed as Roebel conductors or are designed similarly to Roebel.

[0018] In particular, variants with reduced-height conductor sections and / or expanded conductor sections in the braided conductor area can largely be based on a conventional Roebel conductor, as this is preferably formed with strip-shaped individual conductors. However, other braiding forms, such as conductor twists similar to a stranded wire, are also conceivable.

[0019] Particularly preferred is the variant of the multi-element electrical conductor according to the invention in which the individual conductors have the same cross-sectional area over the length of the conductor. These are therefore expediently designed as shaped conductors in the conductor braiding regions in order to represent the conductor fill area. This has the advantage that a continuous conductor cross-sectional area is available for the current flow across all individual conductors.

[0020] In a particularly advantageous embodiment of the multi-element electrical conductor according to the invention, the individual conductors have a constant cross-sectional shape over the respective length of the conductor core regions or across one conductor core region in each case.

[0021] The multi-element electrical conductor according to the invention also has, in particular, a conductor connection region in which the individual conductors are interconnected. This connection region is preferably manufactured additively. This conductor connection region can preferably also be adapted to the outer geometry of the conductor.

[0022] In an advantageous embodiment of the invention, the multi-element electrical conductor is arranged in a slot of an electrical machine. This has the advantage of providing a highly efficient system, since, on the one hand, a multi-element conductor is provided whose relative resistance is minimized, while, at the same time, the external geometry ensures a high fill factor.

[0023] An alternative use of the multi-element electrical conductor according to the invention is proposed in a winding, in particular a winding of a transformer.

[0024] In addition, the invention comprises a method for producing a multi-element electrical conductor as described above, which manufacturing method comprises the following steps:

[0025] Production of a conductor core region and production of at least one conductor braided region, in particular its conductor filling region. Conventional production methods are preferably used for producing the conductor core regions and for producing the continuous individual conductors. The production of the conductor braided regions by braiding or twisting and the production of the conductor filling region takes place in the further production step, which can in particular comprise material removal for a reduced conductor height, which can comprise widening by adding, for example by means of additive processes, to a conductor section in the outer conductor braided region, which can comprise a mechanical process for conductor deformation in the conductor braided region and also additive processes for producing shape-adapted conductor sections in the entire conductor braided region.

[0026] In particular, a step for producing the conductor connection area is also included in the manufacturing process, in which step the individual conductors in the conductor connection area are connected, in particular by means of an additive manufacturing process.

[0027] In a further advantageous variant of the method, two additive manufacturing steps are used, in particular to additively manufacture an upper and a lower conductor filling area or areas on the outer sides of the conductor braiding areas.

[0028] Further features, properties and advantages of the present invention will become apparent from the following description with reference to the accompanying figures. In the exemplary embodiments and figures, identical or similarly acting elements may be provided with the same reference numerals. The illustrated elements and their relative sizes are generally not to be regarded as true to scale; rather, individual elements may be shown larger in size for better illustration and / or better understanding. The figures schematically show

[0029] Figure 1 is a perspective view of a section of a multi-element conductor 1 with Roebel-like interweaving of the individual conductors 10,

[0030] Figure 2 shows a longitudinal section through a multi-element conductor 1 as shown in Figure 1, Figure 3 shows a cross section through a multi-element conductor 1 as shown in Figure 1,

[0031] Figure 4 shows a longitudinal section through a multi-element conductor 2 with a conductor braiding area 21, the outer individual conductors 12 of which have a reduced height,

[0032] Figure 5 shows a cross-section through a conductor 2 , as in Figure 4 with a single conductor section 12 of reduced height,

[0033] Figure 6 is a perspective view of a conductor 3 in cross-section with visible conductor core 30 and conductor braiding area 31 with widened single conductor

[0034] 13 ,

[0035] Figure 7 shows a corresponding cross-sectional view of the conductor 3 shown in Figure 6,

[0036] Figure 8 is a perspective view of a section of a multi-element conductor 4 with shape-adapted conductors

[0037] 14 ,

[0038] Figure 9 shows a cross section through the conductor 4 shown in Figure 8 in the conductor braiding area 41,

[0039] Figure 10 shows several cross sections AA, BB, etc. along a conductor braiding area 51, in which all individual conductors 15 passing through the conductor braiding area 51 are shaped according to their shape,

[0040] Figure 11 shows, in a manner comparable to Figure 10, the cross sections A- A, BB, etc. for a multi-element conductor 5 consisting of six individual conductors 15.

[0041] Figure 1 shows a perspective view of a multi-element conductor 1 which is constructed like a Roebel conductor. It shows 16 individual conductors 10 which are arranged in eight layers, two per layer. The individual conductors 10 are insulated from one another. There are conductor sections in which the individual conductors 10 run parallel to one another along the entire conductor assembly 1. There are sections in which one of the individual conductors 10 of the upper layer is transferred to the position of the adjacent individual conductor 10, so that the individual conductors 10 are intertwined. Typically, there are as many intertwinements along the entire length of the multi-element conductor 1 as there are individual conductors 10 in the conductor assembly 1. The individual conductors 10 in such a Roebel intertwining serve the particular purpose of reducing so-called skin effects and thus energy losses.

[0042] Already in Figure 1, but even more clearly in Figures 2 and 3, which show a longitudinal and a cross-section through the conductor 1 shown in Figure 1, one of the significant disadvantages of the Roebel conductor becomes clear, namely that the total cross-section bxh ' through the braided areas, or in the braided areas, is larger than the cross-section of a solid conductor with a comparable effective conductor cross-sectional area sum of the individual conductors 10. For this reason, such Roebel conductors have so far only been used in very large electrical machines. The use of such conductors has not yet been realized in smaller electrical machines, since the fill factor plays a major role here. The use of a multi-element conductor strand 1 designed in this way in small electrical machines would enormously reduce the degrees of freedom with regard to conductor height and number of turns.In Figures 2 and 3 , h ' indicates the height that would result from continuous conductors 10 without interlacing .

[0043] Since a high fill factor has a significant impact on the performance of the electrical machine, and the slot for the winding must therefore be optimally filled, it is not particularly practical to use a conductor strand 1 that has numerous bulges or indentations on the top and bottom due to the interweaving. This effect is so significant that, for a comparable performance of the electrical machine, up to 20% more electrically conductive individual conductors must be installed to compensate for the reduced fill factor.

[0044] 4 and 5 schematically illustrate a variant of the invention, a multi-element conductor 2, again shown in a conductor cross-section and longitudinal section. The figures show the constant conductor strand height h and constant conductor strand width b, continuous individual conductors 10, as well as, in the conductor braiding area 21, top and bottom conductor filling areas which are formed from conductor sections 12 with a reduced height. A multi-element conductor 2 of this type therefore has, in the conductor braiding areas 21, conductor sections 12 with a reduced conductor cross-section. In the conductor core areas 20 adjoining the conductor braiding area 21 on both sides and also lying inside the conductor braiding area, the individual conductors 10 have consistently constant conductor cross-sections and, as in the case shown, also consistent cross-sectional shapes.The external geometry of the conductor strand 2 is optimized with a constant width b and almost constant height h for a high fill factor when used in an electrical machine.

[0045] The embodiment of a multi-segment conductor 3 shown in Figures 6 and 7 can advantageously also be combined with the embodiment according to Figures 4 and 5, in particular by the conductor section in the conductor braiding region 31 with a reduced height 12 being widened at the same time, as shown in Figure 6. Such a combination could therefore lead to a shape-adapted conductor 13 which is widened in the conductor braiding region 31 and, due to the reduced height, retains the same conductor cross-section as in the conductor core region 30. The multi-segment conductor 3 shown in Figure 6 is shown in perspective, analogous to Figure 1, and once again illustrates the different conductor section regions, namely conductor core regions 30 alternating with conductor braiding regions 31. Both conductor section region types can comprise individual conductors 10, in particular continuous individual conductors 10 which remain constant in their cross-sectional area and shape.The widening of the conductor section 13 in the conductor braiding area 31 also ensures that the irregular surface structures caused by the braiding are further minimized or adapted to a homogeneous external geometry.

[0046] The production of a conductor section 12 with a reduced height as well as a conductor section 13 which is widened, in particular with a simultaneously reduced height, can be carried out in particular mechanically by removal or mechanical material deformation.

[0047] Figures 8 and 9 show a variant of the multi-element conductor 4 according to the invention, which has parallel individual conductors 10 in its core regions 40 and continuous individual conductors 10 in its conductor braiding region, which, however, only change the conductor level, so that their conductor cross-section and cross-sectional shape remain the same, while the conductor sections 14, which change into the adjacent level in the conductor braiding region, are designed to be shaped accordingly. In particular, these conductor filling regions are manufactured additively and almost completely fill the cavities created by the braiding or create a conductor braiding region 41 whose external geometry is almost completely adapted to the external geometry of the conductor core region 40.

[0048] The cross-section in Figure 9 shows once again a variant of the multi-segment conductor 4 which has continuous conductors 10 in the conductor braiding area as well as shape-matched conductors 14 which, however, have a constant cross-sectional area throughout. A multi-segment conductor of this type has the advantage that no protruding or empty sections would reduce the fill factor and, at the same time, high conductivity is made possible by the continuous conductor cross-section. Finally, Figures 10 and 11 show variants of the multi-segment conductor 5 which are spun in the conductor braiding areas 51 in such a way that they continuously change their cross-sectional shape but not their cross-sectional area. This is shown using two examples: in Figure 10 with a four-core conductor and in Figure 11 with a six-core conductor.Within the conductor braiding area 51, five cross-sectional areas AA to EE are shown, starting at AA with rectangular individual conductors 10 running parallel to one another, which have been rotated one place in the conductor layering up to section EE. The direction of rotation is shown by an arrow. The continuous advancement of the individual conductors 10, 15 is shown by Roman numerals. Such a conductor braiding area 51 is expediently produced by means of an additive manufacturing process. Advantageously, the manufacturing process can only be used for the conductor braiding area 51 and can be followed by solid, conventionally manufactured individual conductors 10. This hybrid manufacturing, a combination of conventionally manufactured conductor areas and additively manufactured orFilled conductor areas have the advantage that all areas in which additive manufacturing is not necessary or advantageous can be prefabricated using conventional methods, thus enabling faster production. In the embodiments shown in Figures 8, 6, and 4, additive manufacturing is preferably performed only, if at all, in the conductor filling area, above and below the continuously running conductors 10.

[0049] In all variants shown, the individual conductors 10 are arranged insulated from one another. This can be ensured by electrically insulating layers, coatings, and / or surface treatments, particularly oxidized aluminum layers.

[0050] In summary, the achieved predeterminable external geometry h / b of the multi-element conductor 2, 3, 4, 5 should be emphasized once again. This is realized by the conductor filling areas of the conductor braiding areas 21, 31, 41, 51.

[0051] Conductor filler sections can therefore be reduced-height (12), widened (13), and / or shaped (14, 15) individual conductors. The proposed multi-element conductor (2, 3, 4, 5) accordingly has an outer shape optimized for the fill factor in electrical machine applications.

[0052] In particular, the external geometry h / b of the multi-element conductor strand 2, 3, 4, 5 can remain the same over the length of the conductor, despite the multi-core nature and the Roebel-like interweaving of the individual conductors 10.

[0053] Reference symbol:

[0054] 1 Multi-element electrical conductor

[0055] 10 individual conductors

[0056] 12 single ladders of reduced height

[0057] 13 widened single conductor

[0058] 14 form-matched single conductor with optional variable cross-sectional area

[0059] 15 Shape - adapted single conductor with constant conductor cross - sectional area h ' Varying conductor height , depending on cross - sectional area h Constant conductor height , over the entire length of the conductor 2 , 3 , 4 b Constant conductor width , over the entire length of the conductor 2 , 3 , 4

[0060] 2 Multi-element electrical conductor according to the invention, in particular manufactured in a hybrid manner

[0061] 20 Conductor core area, solid, Roebeled single conductors 10

[0062] 21 Conductor braiding area, especially additively manufactured, with individual conductors of reduced height 12 as conductor filling area

[0063] 3 Multi-element electrical conductor according to the invention, in particular manufactured in a hybrid manner

[0064] 30 Conductor core area, area in which no change in conductor position occurs (even if the individual conductors do not run parallel to the outer geometry, we speak of conductor core area, since the individual conductors run continuously, especially solid, conventionally manufactured conductors, at least all with a constant conductor cross-sectional area, in particular also a constant conductor cross-sectional shape in the conductor core area)

[0065] 31 Conductor braiding area, in particular additively manufactured, with shape-adapted, in particular widened individual conductors 13 and solid, Roebeled individual conductors 10 (conductor braiding area, can be two-part, but can also be a pure filling area; continuous conductor cross-sectional shape for "continuous conductors") Inventive multi-element electrical conductor Conductor core area, straight individual conductors 10 Conductor braiding area, in particular additively manufactured, with shape-adapted individual conductors 14 and position-changing continuous individual conductors 10 with consistently identical conductor cross-sectional area and shape Inventive multi-element electrical conductor Conductor core area, straight individual conductors 10 Conductor braiding area, in particular additively manufactured, with shape-adapted, position-changing individual conductors 15 with consistently identical conductor cross-sectional area

Claims

Patent claims 1. Multi-element electrical conductor (2, 3, 4, 5), having conductor core regions (20, 30, 40, 50) comprising a plurality of individual conductors (10) and having conductor braiding regions (21, 31, 41), which conductor braiding regions (21, 31, 41, 51) are designed to form a predeterminable outer geometry (h, b) of the multi-element conductor (2, 3, 4, 5) by means of at least one conductor filling region, wherein the conductor filling region is manufactured additively.

2. Multi-element electrical conductor (2, 3, 4, 5) according to claim 1, wherein the conductor braiding regions (21, 31, 41, 51) comprise individual conductors (10) and conductor filling regions.

3. Multi-element electrical conductor (2, 3, 4, 5) according to claim 1 or 2, wherein the conductor filling region has a single conductor of reduced height (12), has widened single conductors (13) and / or has shape-adapted single conductors (14, 15).

4. Multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims, wherein the individual conductors (10, 12, 13, 14, 15) comprise copper or are made of copper.

5. Multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims, wherein the individual conductors (10, 14, 15) are solid individual conductors with a material purity of at least 99.96%, in particular conventionally manufactured conductors.

6. Multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims, which is designed as a Roebel conductor or whose conductor core regions (20, 30, 40, 50) are designed as Roebel conductors.

7. Multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims, wherein the individual conductors (10, 14, 15) have the same cross-sectional area over the length of the conductor (2, 3, 4, 5).

8. Multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims, wherein the individual conductors (10) have the same cross-sectional shape over the length of a conductor core region (20, 30, 40, 50).

9. Multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims, comprising a conductor connection region in which the individual conductors (10) are connected.

10. Multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims, arranged in a groove of an electrical machine.

11. Use of a multi-element electrical conductor (2, 3, 4, 5) according to one of the preceding claims in a winding, in particular of a transformer.

12. A method for producing a multi-element conductor (2, 3, 4, 5) according to one of the preceding claims 1 to 10, comprising at least one step for producing the conductor core regions (20, 30, 40, 50) and one step for producing the conductor braiding regions (21, 31, 41), in particular the conductor filling regions.

13. The method according to claim 12, further comprising a step for producing a conductor connection region, in which conductor connection region the interconnection of the individual conductors (10) takes place, in particular by means of additive manufacturing.

14. Method according to one of the preceding claims 12 to 13, wherein the conductor filling region is manufactured by means of an additive manufacturing process, in particular an upper and a lower conductor filling region are manufactured additively.

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