Strip conductor devices used in electrical machines, especially motors, driven by alternating current

Abstract

The present invention relates to a strip conductor device for an alternating current-driven electric machine. It comprises at least two elongated rigid strip conductor elements and a contact device for connecting and disconnecting an electric current. The strip conductor elements are stacked one on top of the other and exchange positions with respect to their positions in the stack at least once within the conductor length. This exchange is achieved without twisting or rotation by complementary steps caused by material deformation.

Description

[Technical Field]

[0001] The present invention relates to a strip conductor arrangement for use in electrical machines, in particular motors, driven by alternating current, comprising at least two elongated, in particular rigid, strip conductor elements together with contact devices for connecting and disconnecting the current, said strip conductor elements providing a current path and forming a layered arrangement with an electrical insulator arranged between them. This corresponds to the subject matter of the preamble of claim 1. [Background technology]

[0002] In high current applications such as generators and high power electric motors, it is known to use so-called lowbel conductors.

[0003] A Lowbel conductor or Lowbel rod typically consists of several individual conductors that exchange positions over the entire transposition length (the term "full transposition length" refers in particular to "V" in FIGS. 1 and 2 of DE 10 2012 218 986 A1 and the associated description) once (whereby the individual conductors return to their original positions along the length of the Lowbel conductor after exchanging positions). This allows the conductors of each section to change position within the winding coil. This is particularly important in terms of minimizing AC losses and reducing coupling losses. Lowbel conductors typically extend over many full transposition lengths, allowing large currents to be carried by a large number of Lowbeled individual conductors.

[0004] When winding a coil of wire, the position of the individual conductors across the length of the conductor is permanently swapped so that the conductors run temporarily on the inside, i.e., at a smaller winding radius, and then later on the outside, i.e., at a larger winding radius.

[0005] DE 39 23 310 C1 gives an example of a method for manufacturing a low-belt rod.

[0006] A Robel rod is a rod made by twisting rectangular profile wire. The profile wire is laid side by side in succession in a Robel tool, with untwisted parallel profile wire and twisted profile wire arranged side by side, and each time the most extreme strand of the untwisted area is separated from the strand to form a Robel rod.

[0007] A double-row bar for windings of an electric machine is disclosed in DE 197 54943 A1. There, partial conductors are arranged in four adjacent stacks. Two adjacent partial conductors are routed in parallel over the entire length of the conductor and twisted in the process. To achieve the desired twist, the partial conductors are offset in the parallel and transverse directions, achieving optimal compensation of transverse and radial magnetic fields during operation of the electric machine.

[0008] CH 15177 A discloses an apparatus for manufacturing interlocked flat conductors. A coil rod, consisting of a plurality of interlocked flat conductors arranged in layers, is placed in a groove in the stator core of an electric AC machine. The free rod ends protruding from the groove extend axially toward the base of the end winding.

[0009] The applicant's WO 2022 / 029008 A1 relates to a method for the additive manufacturing of three-dimensional components having at least one electrical conductor, in particular at least one conductor winding, preferably a coil, preferably a hairpin for an electric machine, in particular an electric motor or generator. The electrical conductor is realized by applying a layer-by-layer laminate material and irradiating the laminate material with a beam to locally selectively solidify the laminate material. The conductor comprises a first region and at least one second region, the first region being at least partially separated by the at least one second region in a cross section perpendicular to the longitudinal direction of the conductor. The at least one second region has a lower electrical conductivity than the first region. The use of regions with different electrical conductivity structures facilitates the creation of structures that positively influence the current flow during the laminate manufacturing process, particularly reducing the effects of eddy currents.

[0010] However, while additive manufacturing of conductor structures offers many advantages, it has been shown that the manufacturing process is very time consuming, which is an obstacle to mass production and increased productivity in the manufacture of such windings and coils. Summary of the Invention

[0011] In view of the above, it is an object of the present invention to provide an advanced strip conductor device for use in electrical machines, particularly electric motors, powered by an AC power source, which is inexpensive, easy to manufacture, and has improved electrical properties compared to the prior art, particularly by reducing losses due to the skin effect and contributing to the realization of a high filling factor.

[0012] The strip conductor arrangement is based on the idea that individual strip conductor elements can be manufactured separately and processed using conventional techniques, for example mass moulding or pressing, thereby ensuring the above-mentioned high productivity, and the manufactured strip conductor elements are joined to form the strip conductor arrangement, cut to length as required and the ends connected.

[0013] The object of the invention is achieved in particular by the combination of features set out in claim 1, the dependent claims representing at least advantageous embodiments and further refinements.

[0014] The invention therefore starts in particular from a strip conductor arrangement for use in electrical machines, in particular electric motors, driven by alternating current.

[0015] The strip conductor device comprises at least two elongated rigid strip conductor elements with contact devices for connecting and disconnecting electrical current, the strip conductor elements providing a current path.

[0016] The strip conductor elements form a layered arrangement with layers of electrical insulation between them.

[0017] In particular, separately manufactured strip conductor elements are provided with a completely enclosed insulating layer and are then stacked on top of each other.

[0018] Thus, in general, at least two strip conductor elements are stacked on top of each other, and the strip conductor elements exchange their stacking position in the stack, i.e., upper or lower position, at least once over their entire conductor length, in particular over the entire transition distance. This exchange of positions is achieved without twisting or rotation due to the complementary steps of the strip conductor elements caused by deformation of the material.

[0019] Preferably, in order to achieve a particularly compact construction, the cross-sectional shape of the strip conductor element varies in the region of the step.

[0020] In the region of the step, the cross-sectional area preferably remains at least approximately constant despite the change in cross-sectional shape, thereby preventing or minimizing the occurrence of hot spots in the strip conductor arrangement.

[0021] Furthermore, the geometric surface shape makes it possible to realize frequency regulation in applications in electrical machines, especially motors, that are driven by alternating current.

[0022] In a further development of the invention, the cross-sectional area (in at least one cross section or in all cross sections) in the region of the step or in the region of at least one step (and / or in the region of at least one recess, in particular in the region of the recess on the width side of the strip conductor element) is adapted to the cross-sectional area of ​​the remaining part of the strip conductor element (in particular at least in at least one cross section of the step at least substantially equal to the cross-sectional area of ​​at least one, and if applicable all, remaining parts of the strip conductor element not included in the region of the step). Preferably, a high uniformity and consistency of the cross-sectional area is achieved.

[0023] The steps preferably have complementary recesses on the width-side surfaces of the strip conductor elements, which recesses are preferably interlocked as a result of the stack being joined (which results in a particularly desirable compact arrangement).

[0024] Preferably, the stack arrangement of the strip conductor device comprises at least two strip conductor elements, each strip conductor element having at least one or at least two steps, and the respective ends of each strip conductor element being electrically connected.

[0025] The stack arrangement is preferably adapted in length and cross-sectional dimensions to the dimensions of the grooves in the stator or core of the electric machine.

[0026] In a preferred embodiment, the strip conductor arrangement forms part of a rectangular coil or forms a so-called hairpin of the electric machine.

[0027] In an embodiment, the strip conductor device is provided on some (or all) of several individual pins (hairpins) of the coil and / or electric machine. For example, the strip conductor device may be provided on at least 1%, preferably at least 8%, more preferably at least 25% and / or up to 90%, preferably up to 70%, more preferably up to 50% of the pins. This allows the advantages of the strip conductor device to be utilized accurately and effectively. Preferably, the pins located more inward of each stator are provided with a strip conductor device, while the pins located more outward are not provided with one.

[0028] The strip conductor elements are preferably flat and narrow and / or at least substantially tightly packed and / or closely stacked, with thin insulating layers disposed between them.

[0029] The insulating layer may be introduced between opposing surfaces of the strip conductor elements in a continuous process when the strip conductor elements are joined to form the strip conductor device.

[0030] This is an alternative or additional measure to coating the individual strip conductor elements with an insulating layer on all sides before joining the strip conductor arrangement.

[0031] The thickness (d1) or (more precisely) layer thickness of the insulating layer is many times smaller than the thickness (d2) of the strip conductor elements (e.g. d1≦0.5*d2 or d1≦0.1*d2 or d1≦0.05*d2 and / or d1≧0.001*d2 or d1≧0.005*d2). Due to the low potential difference between the strip conductor elements, the thickness or layer thickness of the insulating layer can be made extremely small, which allows for a compact design of the strip conductor device with a high fill factor adapted to the intended application.

[0032] The strip conductor elements consist for example of solid copper or copper alloy material and / or solid aluminum or aluminum alloy material and / or are manufactured by layered manufacturing techniques.

[0033] The strip conductor elements can be produced by deformation of material, for example a solid strip of material, preferably having a rectangular cross section, preferably with one or more steps formed therein, and the joining of the strip conductor elements to obtain the strip conductor device can be carried out in an automated manner.

[0034] The production of the strip conductor device can be carried out by conventional methods, in particular by bending and / or welding, especially when forming or comprising geometric hairpins. In general, this can be achieved by (simply) replacing the hairpin with the strip conductor device of the invention.

[0035] The strip conductor elements of the strip conductor device are preferably arranged (in cross section, in particular perpendicular to the longitudinal direction) (at least outside the area of ​​each step and / or outside at least one recess, in particular outside the recess on the width side of the strip conductor element) and / or over at least 50% or at least 90% of their length), one above the other (only), in a row, which allows to save space, whereas at least two rows are always arranged adjacently, as in, for example, a robel bar.

[0036] The strip conductor elements of the strip conductor device are preferably arranged so that they do not adjoin one another (in cross section, in particular perpendicular to the longitudinal direction) (at least outside the area of ​​each step and / or at least one recess, in particular outside the recess on the width side of the strip conductor element, and / or over at least 50% or at least 90% of its length), which allows for space savings, whereas in a Rober bar, for example, at least two rows are always arranged adjacently (in cross section).

[0037] The strip conductor elements of the strip conductor device are arranged in the same direction (at least outside each step or the area of ​​each step, and / or outside at least one recess, in particular the recess on the width side of the strip conductor element, and / or over at least 50% or at least 90% or at least 95% of its length).

[0038] The center lines of each of the strip conductor elements of the strip conductor device may be identical in vertical projection onto the lower surface of the bottom layer and / or the upper surface of the top layer (generally, outside the outermost layer) (at least outside each step or the area of ​​each step, and / or outside at least one recess, in particular outside the recess on the width side of the strip conductor element, and / or over at least 50% or at least 90% or at least 95% of its length).

[0039] The strip conductor arrangement and / or each strip conductor may have at least or exactly two layers, or at least or exactly three layers, or at least or exactly four layers.

[0040] The strip conductor arrangement and / or each strip conductor may have at least one or exactly one, or at least two or exactly two, or at least four or exactly four or more layer jumps / layer jumps (steps / steps), where at least two or exactly two layer jumps (steps) together may represent a transition to the next layer (or to a third layer or further away layer, if there is a corresponding number of layer jumps / steps).

[0041] A (single) layer jump or step can go (directly) from one layer to the next or further layers.

[0042] The strip conductor arrangement may have at least two or exactly two, or at least three or exactly three, or more strip conductors.

[0043] The (respective) step (or layer jump) is preferably located in the respective active area of ​​the strip conductor or strip conductor arrangement. In general, there may be at least one or exactly one, or at least two or exactly two, or three or exactly three, or more dislocations (layer jumps) (per strip conductor arrangement) in each active area of ​​the stator groove.

[0044] The (each) step or steps are preferably arranged in such a way that a (maximum) suppression or reduction of eddy current and / or loop current losses in the total winding (total copper winding) is achieved.

[0045] Preferably, the steps are spaced at a fixed distance from one another within the active area of ​​the stator or motor.

[0046] The strip conductor device can be arranged as a hairpin or as an alternative to a (traditional) hairpin and / or within the winding of the profile wire, in particular to minimize eddy current losses within the winding.

[0047] Strip conductor devices can be configured or used as an alternative to or in addition to stranded wire. [Brief explanation of the drawings]

[0048] The invention will now be explained in more detail with reference to exemplary embodiments and with the aid of the drawings. As shown below: [Figure 1] FIG. 1 is a perspective view of a strip conductor device formed in accordance with the present invention, in which two strip conductor elements are joined together, the strip conductor elements having already been provided with an enveloping insulating layer; [Figure 2] FIG. 2 is a side view similar to FIG. 1 , showing the state in which the insulating layer is embedded by the steps in the stepwise joining process of two strip conductor elements to form a strip conductor device; [Figure 3] FIG. 3 is a schematic side view illustrating an alternative embodiment of a strip conductor device; [Figure 4] Figure 4 is a perspective view of a strip conductor device designed in a U-shape (hairpin shape); [Figure 5] FIG. 5 is a schematic cross-sectional view of a stator with a strip conductor device in one embodiment; [Figure 6] FIG. 6 shows another embodiment according to FIG. 5; and [Figure 7] FIG. 7 is a diagram similar to FIG. 5 in yet another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0049] The illustrated strip conductor device consists of two strip conductor elements 1;2 superimposed on one another.

[0050] The strip conductor elements 1 and 2 exchange positions over the conductor length relative to their positions in the stack, over the course of the total displacement distance VS (shown diagrammatically in FIG. 2, ending at the start of the layer jump and then completing the total displacement).

[0051] In the example shown in FIG. 1, the strip conductor element 1 is located at the top left of FIG. 1 and swaps positions downwards by a step SP.

[0052] The strip conductor elements (strip conductor sections) 2 exchange positions from below to above by the steps SP according to the example shown in FIG.

[0053] It can be seen from the drawing that the interchange of the strip conductor elements is achieved without twisting or rotation by the complementary steps SP (caused, for example, by material deformation) of the strip conductor elements.

[0054] In the region of the step SP, the cross-sectional shape of the strip conductor elements 1; 2 changes.

[0055] By adjusting the shape in the step SP region, it is possible to change the cross-sectional shape while keeping the cross-sectional area almost constant, thereby avoiding heat concentration due to current.

[0056] Preferably, the cross-sectional area of ​​at least one cross section (and if possible all cross sections) in the region of the (each) step is at least 0.6 times, preferably at least 0.9 times, and / or at most 1.5 times, preferably at most 1.1 times, the cross-sectional area of ​​at least one cross section (and if possible all cross sections) of the corresponding strip conductor element outside the region of the step.

[0057] Preferably, the (smallest) width of each strip conductor within the region of the step is smaller than the width of the corresponding strip conductor outside the region of the step, preferably at least 10% or at least 30% smaller and / or up to 80% smaller.

[0058] Preferably, the (maximum) thickness (height) of each strip conductor within the step region is greater than the thickness of the corresponding strip conductor outside the step region, preferably at least 10% or at least 50% greater and / or up to 200% greater.

[0059] Within the scope of the invention, the cross-sectional area in the region of the step SP is at least substantially adapted to the cross-sectional area of ​​the remaining parts of the strip conductor elements 1;2 and is, if possible, designed identically.

[0060] The steps SP have complementary portions 3 on the width sides of the strip conductor elements, and the gaps are connected by joining (see FIG. 1).

[0061] By joining the strip conductor elements 1;2, preferably using a mechanical device, a strip conductor device is obtained as seen from right to left in Figure 1, in which the strip conductor elements 1;2 are stacked flat, tightly and closely together to form a compact arrangement.

[0062] In particular, when non-insulated strip conductor elements 1;2 are used, a thin insulating layer 4 is inserted between the strip conductor elements 1;2 in the process of overlapping the strip conductor elements 1;2 (see FIG. 2).

[0063] This insulating layer 4 may be pre-shaped to a contour in the region of the step SP or may consist of a material which takes on its shape in the region of the step when the strip conductor elements 1;2 are joined.

[0064] The strip conductor elements 1;2 are made of solid copper or copper alloy material, which is advantageous for more efficient and cost-effective manufacture. Using known material deformation methods (preferably employed), a full strip material, preferably having a rectangular cross section, can be formed such that the steps of forming the relevant steps SP and joining the strip conductor elements 1;2 to form the strip conductor device can be carried out in a simple and automated manner.

[0065] An important advantage of the proposed strip conductor device is that when using the strip conductor device in an electric machine, the nonlinear conductor structure with steps reduces the contact area in the groove intersection region. Furthermore, current deflection is minimized. By geometrically adjusting the shape of the conductor, it is possible to respond to different frequency spectrums during operation of the electric machine. Potentially increased current densities in the step region can be reduced by geometrically adjusting and optimizing the shape.

[0066] When comparing copper losses that depend on the conductor shape based on known twisted conductor structures with copper losses in the strip conductor device of the present invention, the frequency-dependent increase in loss when using a strip conductor device with a stacked arrangement and steps of strip conductor elements is significantly reduced, particularly in the frequency range from 500 Hz to 1500 Hz, and in some cases from 600 Hz to 1000 Hz.

[0067] 3 shows a schematic side view of an alternative embodiment of a strip conductor arrangement, which may consist of strip conductor elements 11; 12; 13 forming three layers with multiple steps (e.g. from the bottom or first layer shown in the figure to the middle or second layer and from there to the top or third layer).

[0068] Figure 4 shows a strip conductor arrangement designed in a U-shape (hairpin shape). Here it can be seen that in each active area A of the strip conductor only one layer displacement (layer jump) is provided. In general, in (each) active area (per strip conductor arrangement) of the stator groove there may be at least one or exactly one, or at least two or exactly two, or at least three or exactly three, or more dislocations (layer jumps).

[0069] FIG. 5 shows a schematic cross-sectional view of a stator 14 in which a plurality of strip conductor devices 21, 22, 23, 24, 25, and 26 are formed (in stator slots). The exact number of strip conductor devices is not necessarily important here. It can be seen that all of the strip conductor devices are designed in accordance with the basic principles of the present disclosure (in accordance with claim 1). In another embodiment shown in FIG. 6, a plurality of inner strip conductor devices (specifically, four, but not limited to) are formed in accordance with the basic principles of the present disclosure, and other outer strip conductor devices (here, two) are transposed without corresponding steps in accordance with the present disclosure. In this embodiment, specifically, two-thirds (but not limited to) of the strip conductor devices are designed to have steps in accordance with the present disclosure.

[0070] In yet another embodiment shown in Figure 7, the innermost (or two innermost) strip conductor devices are designed with at least one corresponding step in accordance with the present disclosure, while the outer ones (here four) are not, so that one-third (again, not in a limiting sense) of the strip conductor devices are designed with at least one step in accordance with the present disclosure.

[0071] In this regard, all parts described above (considered individually or in any combination), including the details particularly shown in the drawings, are claimed as essential elements of the invention, modifications of which are within the knowledge of those skilled in the art.

[0072] It is further pointed out that the broadest possible scope of protection is sought. In this respect, the disclosure contained in the claims may be characterized by features described in more detailed features (though these features do not necessarily have to be included). Parentheses and the term "in particular" are used to emphasize the optionality of a feature in the respective context (and conversely, the absence of such indication does not imply that the feature is essential). The term "element" should preferably refer to a respective coherent structure that is connected to at least one other structure (to form an integral and / or immovable whole structure) or may be separated from all other structures.

[0073] Reference Code List 1,2 Strip conductor element 11;12;13 Strip conductor elements 14 Stator 21;22;23;24;25;26 Strip conductor device

Claims

1. 1. A strip conductor arrangement for use in an electrical machine, particularly a motor, powered by an AC power source, comprising: at least two elongated rigid strip conductor elements (1; 2) provided with contact devices for connecting and disconnecting electrical current, said strip conductor elements (1; 2) providing a current path, said strip conductor elements (1; 2) forming a layered arrangement with an electrical insulator (4) arranged between them; The strip conductor elements (1; 2) are stacked one on top of the other and exchange positions with respect to their positions in the stack at least once during their conductor length, in particular the complete transposition distance (VS), and the exchange is realized without twisting or rotation by complementary steps (SP) of the strip conductor elements (1; 2), preferably by material deformation. Strip conductor device.

2. In the region of the step (SP), the cross-sectional shape of the strip conductor element (1; 2) changes.

2. The strip conductor device according to claim 1.

3. In the step (SP) region, the cross-sectional area is substantially constant even if the cross-sectional shape changes.

3. The strip conductor device according to claim 2.

4. the cross-sectional area of ​​the step (SP) is adapted to match the cross-sectional area of ​​the remaining part of the strip conductor element (1; 2); 4. The strip conductor device according to claim 3.

5. The steps (SP) each have complementary recesses (3) on the width side of the strip conductor element, and these recesses are configured to interlock with each other when the stack is joined. A strip conductor arrangement according to any of the preceding claims.

6. a stacked arrangement consisting of at least two of said strip conductor elements (1; 2), The strip conductor element (1; 2) has at least one or at least two steps (SP), and the respective ends of the strip conductor element (1; 2) are electrically connected. A strip conductor arrangement according to any of the preceding claims.

7. The arrangement of the stack is adapted in length and cross-sectional dimensions to the dimensions of the grooves of the stator or core of the electric machine.

7. The strip conductor device according to claim 6.

8. It is characterized in that it constitutes a part of a rectangular coil or a hairpin.

8. A strip conductor device according to claim 1.

9. The strip conductor elements (1; 2) are thin, tightly stacked without gaps, with thin insulating layers (4) between them, forming a compact arrangement.

8. A strip conductor device according to claim 1.

10. The thickness or layer thickness of the insulating layer (4) is several times smaller than the thickness of the strip conductor element (1; 2).

10. The strip conductor device according to claim 9.

11. characterised in that the strip conductor elements (1; 2) are made of solid copper or copper alloy material or are manufactured by additive manufacturing techniques. A strip conductor arrangement according to any of the preceding claims.

12. The invention has at least one coil, in particular a rectangular coil, and is equipped with at least one strip conductor arrangement according to any of the preceding claims. Stator and / or electric machine.

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