Stator and method for producing a stator

Abstract

A stator is provided which comprises: at least one coil unit with a plurality of conductors, comprising at least one waveguide, wherein at least some conductors are electrically connected to one another in series, and a stator core which has at least one receiving region, wherein one or more conductors are received in the receiving region, wherein the conductors are at least partially different from one another.

Description

Technical FieldThe invention relates to a stator for an electric machine and to a method for producing such a stator. The invention further relates to an electric machine having such a stator.Prior ArtThe design of electrical machines with a hollow conductor winding already allows a significant increase in the current density through the principle of direct winding cooling. However, the integration of the cooling function into the current-carrying hollow conductor creates a conflict of optimization between an optimum design of the electric machine, in particular of the winding from an electromagnetic point of view, and an optimum design of the hollow duct and thus of the conductor from a fluidic or hydraulic point of view on the side of the cooling system.From a fluidic point of view, it is often preferred to use large hollow channels and thus comparatively massive hollow conductors, so that the pressure drop to be covered by a coolant pump when pumping the coolant through the hollow conductor winding is as low as possible. The aim is to use a coolant pump that is as compact and cost-effective as possible.From the perspective of optimum electromagnetic dimensioning, it is advantageous in the case of power density drives with a high polarity alternating frequency to use conductors which are as thin or flat as possible. With this configuration, additional losses in the winding generated by the current displacement effect are suppressed. These additional losses add up to the ohmic losses in the current-carrying conductor and lead to an undesired reduction in the efficiency and to additional heating of the stator.In industrial series-produced electric machines, a waveguide wire is continuously processed from a reel and wound up into a coil. Thus, the conductor is fixed and identical in type and dimension, i.e. in its shape and size, for each position of the conductor in the slot of the stator. The described optimization conflict and the associated disadvantages in the design of the conductor are defined by the selection of a certain wire.In the field of large engines with a power of more than 1,000 kW, such as in turbogenerators, for example, hollow conductor cooling is state of the art. Here, it is customary to process not only a single wire but a bundle of hydraulically and electrically parallel-connected waveguide wires to form a coil. Wound coils are used and with each winding of the coil a defined and identical cross section through the conductor bundle repeats in the successive positions (alternative designation "layers") within a stator slot. The described optimization conflict and the associated disadvantages are also defined here by the selection of the wire or wires within the recurring bundle.Due to the technology of additive manufacturing, in theory, very fantasiely shaped and, with respect to the position within a specific slot, an optimized conductor geometry can be printed as a complete winding. However, this technology is significantly more energy-intensive and thus more expensive than the conventional continuous drawing and coating of wire from the reel and thus does not represent an alternative for a series production optimized for low costs and high speed.For example, document DE 10 2021 119 405 A1 is known, which relates to a stator for an electric machine, which has a stator package with at least one stator slot, in which at least two electric conductors are arranged. At least a part of the stator is produced by means of a method for additive manufacturing, wherein, in the case of a predetermined number of the electrical conductors, in each case at least one cooling duct to which a cooling fluid can be applied is configured, wherein at least a first and a further cooling duct group, in each of which the cooling ducts of a plurality of electrical conductors can be applied with cooling fluid in parallel with one another, are connected fluidically to separate circuits or to a circuit in series and / or in parallel.In the field of electric wave guide machines, document DE 10 2020 201 748 A1 is also known, which relates to an electric machine with a stator, which has slots for receiving an electric plug winding, wherein the electric plug winding is a distributed polyphase winding and is formed from electric conductor elements lying in the slots. A plurality of the conductor elements of the plug-in winding is designed as a hollow conductor, on one of the two end windings a coolant distributor is provided, which is electrically insulated from the hollow conductor elements, has an inlet for supplying an electrically non-conductive coolant, in particular oil, from a coolant supply, and from which the coolant can be conducted into a plurality of the hollow conductor elements.The publications described have in common that a defined shape or also arrangement of the conductor or conductors is present along the electrical path of a coil and / or along a stator groove.The Invention Subject MatterAn object of the invention is to provide a stator which leads to a higher efficiency in an electric machine and which enables a compact, material-saving and cost-effective construction.The stator according to claim 1 provides a solution for this. Further preferred embodiments are explained in the dependent claims and in the following description.According to the invention, a stator is provided, comprising: at least one coil unit having a plurality of conductors, comprising at least one waveguide, wherein at least some conductors are electrically connected to one another in series, and a stator package which has at least one receiving region, preferably a plurality of receiving regions (in particular three or more receiving regions), wherein one or more conductors are received in the receiving region. The conductors differ from one another at least partially.Since the conductors of a coil unit differ at least partially, one conductor can be configured differently from the other conductors (which could be the same, for example). However, a plurality of conductors may also differ from one another.In particular, the conductors, preferably a coil unit, are electrically in series.In particular, the conductors differ in their shape and / or configuration, as viewed in a cross section. Thus, a stator having high efficiency and an optimized structure can be provided.The stator according to the invention provides in particular a structure in which a shaping and arrangement of conductors is optimized according to the position within the receiving region.In particular, a variation of the conductors can be effected in that an outer shape, in particular a width and / or height, a configuration as a waveguide or solid conductor, a configuration as an individual conductor or conductor bundle, and / or a shape and / or a diameter of a channel (in the case of a waveguide) are varied.It is also possible to use a solid conductor not designed as a hollow conductor without a channel, or an arrangement of a plurality of hollow conductors or a plurality of solid conductors electrically connected in parallel within this part of the winding, or a mixed form of both.The individual conductors which differ from one another at least partially (for example waveguides, solid conductors and / or bundles of waveguides and / or solid conductors, or as a mixed form thereof) form portions of a serial current path.The individual conductors, which differ from one another at least partially, form in their entirety a coil unit with two electrical connections.These conductors as parts of a coil unit are also referred to below as pins. Pins may differ in that those pins which run through a single receiving region, in particular a single slot, wherein a start and an end of such pins each end in an opposite winding head of the stator are referred to as "I pins", while pins which run through two receiving regions, in particular slots, of a stator have a start and end in the same winding head are referred to as "hair pins"."Pins" and "conductors" are used below as synonymous terminology, wherein an arrangement of the pins / conductors connected electrically in series forms a coil unit as described, wherein the pins / conductors can be designed as waveguides or solid conductors or as bundles of hollow or solid conductors or as a mixed form of the like.One or more identical coil units can be electrically interconnected with one another as desired, both in series and in parallel or as a combination of series and parallel connection with one another, as conventional coils. The interconnected coil units form in total phases or strands of a polyphase electric machine.The position of the connection points of the individual conductors of a coil unit outside the slot of the stator is usually referred to here as "winding head", even if in this case it is not exactly the same wire that continues to be wound, but rather the conductors are electrically contacted with one another as parts of a coil unit in the winding head.Within a coil unit there is at least one waveguide or a bundle of electrically (and hydraulically) parallel waveguides. The individual hollow conductors each have an inlet and outlet for the coolant at their respective ends, which preferably open in the winding head into a hydraulic collector for the inflow and outflow of the coolant.It is preferred that a collector is provided at each of the opposite ends of the stator stack and the conductors are hydraulically connected in parallel. According to another embodiment, a collector for an inlet and an outlet of a coolant is arranged on a same side of the stator stack.In an advantageous embodiment, the hydraulic accumulator is made of an electrically insulating material and extends at least partially over the region of the winding head and in particular over the region of the contact points of the pins in order to insulate the end pieces of the pins, which are possibly situated close to one another and are insulated from one another for the purpose of the electrical contacting in this region.In a particularly advantageous embodiment, all the conductors installed in the stator are hollow conductor I pins, and if present in this way, including all hollow conductor I pins, which are already connected hydraulically and electrically in parallel as individual elements of a hollow conductor bundle, are hydraulically connected in parallel to one another, wherein the channels of the hollow conductors each open into a annularly running hydraulic collector on both sides of the stator, wherein a cooling liquid flows through the hollow conductors in the same axial direction of the stator.In a further particularly advantageous embodiment, the conductors are designed as waveguide hair pins and are arranged in such a way that all ends on one side of the stator with or after the winding head open into annular collectors, wherein at least one annularly encircling collector is provided for the inlet and at least one annularly encircling collector is provided for the outlet of the cooling liquid.These advantageous designs can be applied analogously to axial flow machines with an inner and outer annular collector, and also for transverse flow machines and for electric machines with one or a plurality of stators and thus in each case a plurality of both inlet collectors and outlet collectors.The arrangement according to the invention provides for a particularly advantageous arrangement in which "outer" layers which lie at the air gap between stator and rotor use a particularly thin and / or flat design of the hollow conductors or solid conductors or finely segmented bundle of conductors / pins (in particular a bundle of flat wires), because this design very effectively suppresses the so-called AC winding losses which are generated in particular in the outer layers by the current displacement effect.In the "lower" layers in the groove base, wherein the groove base means the closed lower side of the groove on the stator yoke, if present, a massive construction of the waveguides can be present, for example, so that a comparatively high fill factor with the material of the conductor, in particular copper or aluminum, can be realized. The current displacement effect is less significant in this range. Thus, in each position / location of the slot, an optimum compromise can be found of suppression of current displacement losses by thin and / or segmented conductors (conductor bundles) and a reduction of ohmic DC winding losses by a high fill factor with solid and / or unsegmented conductors.Primarily, the shape or the cross section through the conductors or conductor bundles within the stator slots or on the active length of the stator stack is described. This shape or this cross section can continue at least partially in the region of the winding head, wherein a slight change in shape can take place in one or the two end sections of a conductor for the purpose of better contacting or due to the process of stripping. The fact that the conductors are surrounded with an electrically insulating layer, except in the region of the contacting of their end sections, in order to insulate them from one another, is self-evident to the person skilled in the art and is not separately emphasized in the figures and the further description.It is also self-evident in the field of electric machines that the stator is made of a soft magnetic material, usually designed as a stack of electric sheets, wherein SMC or printed soft magnetic elements can also be used.Not described further or shown in the figures, but it is likewise understood that a further layer of insulation material is usually provided, which is laid around the conductors or inserted into the grooves.Furthermore, the receiving region of the winding in the stator package can be designed as a slot, wherein the slots of a stator are usually designed as parallel slots, since they are matched to the fixed width of a conductor.A stator according to the invention makes it possible to design receiving regions or grooves with trapezoidal flanks or in a stepped manner, so that a maximum fill factor with the conductor material, e.g. copper or aluminum, can be achieved. In an advantageous embodiment, for the example of a radial flux internal rotor machine, the conductors in the slot base are made wider than those which are closer to the air gap. A further advantage of the stepped configuration of a slot is the better fixing of the pins / conductors in the slot when the stator is fitted, and the better thermal connection between the stator package and the pins / conductors.It is furthermore advantageous that one or more of the conductors are designed as solid-conductor or hollow-conductor bundles. This relates in particular to the part or parts of the coil unit which are arranged closer to an air gap of the stator.The end portions of the conductors are electrically contacted or joined to one another as described. In an advantageous embodiment, the (stripped) end sections can be connected in particular in pairs to a sleeve, preferably enclosed by a sleeve, wherein the sleeve in a further advantageous embodiment does not influence the hydraulic path of a coolant through the hollow conductor channel. The sleeve mentioned can encompass the end sections. The sleeve may have an opening region, or according to another embodiment, the sleeve is formed closed.It is preferred that the sleeve, in addition to the joining connection of the conductors to one another, effects an electrical coupling of the end sections of the conductors and is likewise manufactured from an electrically (well) conductive material such as copper.Furthermore, it can be provided that the sleeve has features, e.g. webs or tabs, for clamping or pressing around the end sections of the conductors. It is furthermore preferred to fill the contact region between the sleeve and the conductor end sections with solder in order to achieve ideal electrical contacting. Other joining methods, such as welding or pressing, are likewise possible.Furthermore, it can be provided that the conductors have a rectangular cross section.The respective end sections of the hollow conductors open into one or a plurality of hydraulic accumulators. A collector can be formed from an electrically insulating potting compound, which extends at least in sections around the end sections of the individual conductors.The collector can have one or a plurality of elevations which, in an advantageous embodiment, are designed as a circumferential web or circumferential webs, in particular between end sections which are not contacted with one another in pairs via end sections of the conductors or sleeves and thus have a voltage difference with respect to one another during operation. By means of this elevation(s) or web(s), the air and creepage distance between such conductors which have a voltage difference with respect to one another during operation can be increased. This allows a winding with a higher number of layers to be provided in the slot or an electric machine to be designed for a higher voltage class, which opens up a higher design freedom in the design of an electric machine and consequently means a more optimized machine with a higher efficiency.According to a preferred embodiment, the conductors form a coil unit, wherein the coil unit has a helical or meander-shaped course. A coil unit is formed by a plurality of electrically series-connected conductors.According to a further aspect of the invention, an electric machine is provided, comprising a stator according to one of the preceding embodiments. With regard to the advantages of this electric machine, reference is made to the explanations relating to the stator described above.In a further embodiment, the electric machine can have a stator and two rotors, in particular a double rotor with mechanical coupling of both rotors, an outer and an inner rotor in the case of a radial flow machine. An advantage of such an arrangement is the elimination of the stator yoke. The individual stator teeth can be connected to one another via thin webs or a plurality of webs for the purpose of mechanical fixing. In such a dual rotor arrangement, the stator has two air gaps to the two rotors. It is preferred that the conductors which are located at the respective air gap are designed as conductor bundles or waveguide bundles, while the conductors "in the interior" are preferably designed as unsegmented solid waveguides or conductors. In a further embodiment, the arrangement of the conductors can be embodied symmetrically and can be combined as desired, for example with the stepped embodiment.Hair pins are particularly advantageously suitable for double rotor arrangements, since the mechanical coupling of the rotors does not allow access to the winding head on both sides of the stator. The embodiment of such a stator with hair pins entails that two adjacent layers have the same type of conductor (for example, in the case of hollow conductors, the same cross section of the channel), since the two end sections of a hair pin run offset to one another, that is to say in different layers. According to the position of the conductor end sections, the hydraulic contacting or the attachment of the hydraulic accumulators takes place on one side of the machine.In an advantageous arrangement, the plurality of hydraulic accumulators is mounted concentrically in a radial flow machine and simultaneously along an axis of rotation of the rotor in an axial flow machine.An electric machine can be designed as a radial flux machine with a rotor of internal rotor design. The radial flow machine can likewise be designed in an external rotor design or in a dual rotor design. The principle can be applied to other electric machines, likewise for electric machines having one or a plurality of stators or having one or a plurality of rotors, analogously to the mentioned axial-flow and transverse-flow machines.Although in the present case a distributed winding of I-pins is primarily described, the procedure according to the invention can equally also be used with stators with concentrated winding.According to a further aspect of the invention, a method for producing a stator is provided, wherein the stator comprises at least one coil unit having a plurality of pins / conductors, wherein at least one conductor is designed as a waveguide. The conductors of the coil unit differ from one another at least partially. The method comprises the steps of: providing a stator core which has at least one receiving region, preferably a plurality of receiving regions (in particular three or more receiving regions), and inserting the conductors into the receiving region, wherein the conductors are electrically connected in series with one another.In particular, a variation of the conductors can be effected in that an external shape, in particular a width and / or height, of a configuration as a waveguide or solid conductor, of a configuration as an individual conductor or conductor bundle, and / or a shape of a channel and / or a channel diameter (in the case of a waveguide) are varied. Within a conductor bundle (alternatively referred to as segmented conductor), all individual conductors are electrically connected in parallel, and if waveguides are used in the bundle, they are also hydraulically connected in parallel. A segmented conductor / the conductor bundle can be constructed from a plurality of waveguides or a plurality of solid conductors or a mixed form of waveguide(s) with solid conductor(s).The method comprises the steps of: providing a stator core which has a receiving region in the form of an open groove, inserting a plurality of conductors into the receiving region, electrically contacting the conductors.The extension of the method can comprise: providing a stator package which has a receiving region in the form of a closed or partially closed groove, inserting a plurality of conductors into the receiving region in the axial direction (for a radial flux machine), deforming the straight end / ends of the conductors inserted through the stator in the region of the winding head ("twisting"), electrically contacting the conductors.Brief Description of the DrawingsFIG. 1 a illustrates an overall configuration of a winding for a stator consisting of a plurality of coil units of waveguide I pins connected in series. FIG. 1 bshows a detailed view of a coil unit according to the invention, which is composed of waveguide I pins and a bundle of waveguides in an electrically serial arrangement, wherein the bundle of waveguides itself is electrically connected in parallel. FIG. 1 cshows a detailed view of a further coil unit according to the invention according to a modification (meander-shaped arrangement). FIG. 2 shows an arrangement of waveguides according to a first embodiment, which differ in size and type. FIG. 3 shows an arrangement of waveguides according to a second embodiment in a trapezoidal groove with a stepped flank. FIG. 4 shows an arrangement according to a third embodiment for a stator of a dual rotor machine, wherein the conductors are designed as waveguide hair pins and waveguide bundle hair pins. FIG. 5 shows an arrangement of waveguide sections in a hairpin design according to a fourth embodiment for a stator of a dual rotor machine, wherein the conductors are designed as waveguide hair pins of different heights. FIG. 6 shows an arrangement of conductors according to a fifth embodiment. FIG. 7 shows an arrangement of conductors according to a sixth embodiment. FIG. 8 shows an arrangement of conductors according to a seventh embodiment, wherein waveguide I pins are combined with waveguide bundle I pins and a bundle of full flat wire. FIG. 9 is a view of an end portion of a stator according to an embodiment of the invention.DESCRIPTION OF EMBODIMENTSExemplary embodiments of the invention are described below with reference to the figures. Features of the respective embodiments can be combined with one another in order to form further variants.FIG. 1 a illustrates an overall configuration of a winding of a stator of a plurality of coil units used for an electric machine. The coil unit is to be understood as a combination of conductors (here: waveguide I pins) 20 electrically connected in series, wherein the individual conductors 20 differ from one another in terms of type and / or shape, as described below with reference to the embodiments.FIG. 1 bshows an arrangement according to the invention, in which the conductors 20 within the coil unit are formed differently. In this case, as conductors 20, waveguide I pins are combined with a bundle of waveguide I pins connected electrically in parallel. The individual conductors are each located in different positions in the stator grooves (in the inserted state and wherein the bundle lies completely in one position), wherein this arrangement enables all conductors 20, independently of the electrical contacting, to be connected hydraulically in parallel to the respective inlet and outlet collectors, which leads to a very low hydraulic pressure requirement and to a very effective cooling of the conductors. End portions of the conductors 20 are connected in pairs to a sleeve 15, wherein the sleeve 15 encloses the conductors 20 from the outside.In FIG. 1 b, a coil unit (without a stator pack with slots) is shown, which extends radially from an air gap to a slot base like a "coil". By way of example here with four serial conductors 20, however, conductors 20 could also be 2, 4, 6, 8 etc. In this case, "positions / positions skipped by one" in a respective slot are occupied, and are occupied by half the number of conductors of an entire coil unit.FIG. 1 cshows a modification to the embodiment shown in FIG. 1 b. In this case, no "coil" is formed, but rather a meander-shaped course which moves along the "unwound" stator and occupies only one slot with a conductor. Pictorially, the ladder 20x rises "as on a staircase" along the groove. In this case, the conductors 20 xmay alternatively also be interconnected like classic hair pins and may completely circulate in adjacent layers before said staircase-like rise into the next layers occurs. End portions of the conductors 20 xare connected in pairs to a sleeve 15 x. Other joining processes such as welding can also be provided for contacting the end sections.FIG. 2 shows a single groove enclosed by stator teeth and filled with a plurality of conductors (here: hollow conductor pins) of different design. A stator package 30 of the stator has a plurality of receiving regions (stator grooves) 31. The stator shown here is provided for a radial flux machine which is designed as an inner rotor, wherein the explained principle can also be transferred to an outer rotor, and also to axial flux motors, and motors with a plurality of stators or motors with a plurality of rotors.According to the first embodiment shown in FIG. 2, the stator stack 30 comprises stator slots 31 in the form of a partially closed slot. The partially closed groove is surrounded by tooth tips which point towards each other. In this accommodation region (the stator slot) 31, a plurality of types and size variations of conductors formed as waveguide I pins are accommodated. In particular, it is a first waveguide 20 a, a second waveguide 20 b, a third waveguide 20 c, a fourth waveguide 20 d, a fifth segmented conductor as a bundle of electrically parallel-connected waveguides 20 eand a sixth segmented conductor as a bundle of still smaller and electrically parallel-connected waveguides 20 f.The configurations of the (hollow) conductors 20 a- 20 fdiffer from one another in each case according to the invention.It is advantageous that the segmentation of the conductors or the height of the individual conductors increases towards an air gap between stator and rotor. This structure ensures that so-called AC winding losses, which can be generated by a current displacement effect in particular in the layers at the air gap, are suppressed. These losses add up to the ohmic losses in a conductor through which current flows and lead to additional heating and lowering of the efficiency of the electric motor.The inner conductors 20 aand 20 bare formed by a comparatively massive hollow conductor (a hollow conductor with a comparatively pronounced wall) in order to provide a better fill factor within the groove. The previously described current displacement effect, which is clearly pronounced in the region of the air gap, is less relevant in this deep section of the receiving region 31.FIG. 3 shows a second embodiment of a stator which, like the first embodiment, has a stator package 30' and receiving regions formed therein (a receiving region 31' is clearly shown in FIG. 3). The stator shown in FIG. 3 is provided for a radial flux machine which is designed as an internal rotor. However, the principle shown can also be transferred to an external rotor, as already explained in the context of the first embodiment.The tooth of the stator stack 30' shown from a left side in FIG. 3 has a rectilinear surface for forming the receiving region 31', wherein, if embodied in this way on both sides, the resulting tooth has parallel flanks, whereas the groove is formed trapezoidal. In FIG. 3 on the right side of the stator stack 30', the tooth shown has a stepped flank, whereby a tooth with stepped flanks is formed, which provides approximately identical, but not identical, cross sections for the conduction of the magnetic flux. The advantage of this respective configuration is uniform saturation of the soft magnetic tooth with magnetic flux and comparatively more installation space for the waveguides in the groove, which leads to a reduction in the current density in the conductor, fewer conductor losses and an improved efficiency.With regard to further aspects, reference is made in addition to the embodiment described above.Referring to FIG. 4, a dual rotor assembly of a radial flow machine is illustrated. This arrangement comprises a stator package 30'', which has a first receiving region 31''-1 and a second receiving region 31''-2.According to a modification of the embodiment shown in Fig. 4, a plurality of ridges are provided for structurally connecting the teeth. According to another modification, it is also possible to provide individual teeth of the stator stack without a web.In the first receiving region 31"-1, which is designed as a partially closed groove, a first conductor 20a", a second conductor 20b", and a third conductor 20c" are provided, whereas in the second receiving region 31"-2, a fourth conductor 20d", a fifth conductor 20e", and a sixth conductor 20f" are arranged.In this design, both I pins and hair pins are possible. The design with hair pins is particularly advantageous in the case of double rotor motors, since it makes it possible to mount the hydraulic accumulators on a single end face of the stator, due to the limited access due to the double rotor. In this case, the "outer" conductors 20a" and 20f" are designed at the respective air gap such that the waveguide dimension, in particular the heights, is small compared to the "inner" conductors 20c" and 20d". The embodiment as a hairpin variant entails that the adjacent layers 20a" are designed to be 20b, 20c" to be 20d" and 20e" to be 20f", i.e. in each case the same geometry and / or the same type, since a hairpin conductor jumps one layer through two slots through a stator package in each case. Furthermore, a variation between an electrically parallel waveguide bundle and a single (hollow) conductor is illustrated.With regard to further aspects, reference is made in addition to the embodiments described above.The fourth embodiment shown in FIG. 5 corresponds in part to that of FIG. 4, so that reference is made in addition to the explanations relating to the third embodiment. However, the dimensions and configurations of the conductors 20a"', 20b"', 20c"', 20d"', 20e"' and 20f"' are different from those of Fig. 4.FIG. 6 shows a fifth embodiment of a stator in a dual rotor arrangement. The stator comprises a stator package 30''', which has a first receiving region 31'''-1 and a second receiving region 31'''-2. The receiving regions 31'''-1 and 31'''-2 are separated from one another by a web 32''''. In the first receiving region 31'''-1, a first conductor 20a''', a second conductor 20b''', and a third conductor 20c'''' (which are designed as a waveguide-hairpin bundle and a waveguide-hairpin) are arranged. Similarly, a fourth conductor 20d''', a fifth conductor 20e''', and a sixth conductor 20f'''' (which are likewise each designed as a waveguide-hairpin bundle and waveguide-hairpin) are provided in the second receiving region 31'''-2.The first receiving region 31'''-1 is provided with a step which allows the hairpin waveguide bundle of the outer layers 20a'''' to be wider with 20b'''' and therefore with reduced current density. The advantageous reduction of the current displacement losses due to flatter individual conductors compared to the inner layers has already been described.FIG. 7 shows a dual rotor arrangement with an I-pin design according to a sixth embodiment. In this case, a first receiving region 31''''-1, a second receiving region 31''''-2 and a third receiving region 31''''-3 are provided in the stator pack 30''''. A first web 32''''-1 is formed between the first receiving region 31''''-1 and the second receiving region 31''''-2, and a second web 32''''-2 is formed between the second receiving region 31''''-2 and the third receiving region 31''''-3.In the first receiving region 31''''-1, a first conductor 20a'''', which is designed as a waveguide bundle according to this embodiment, is received. In the second receiving region 31''''-2, a second conductor 20b'''', a third conductor 20c'''', a fourth conductor 20d'''', and a fifth conductor 20e'''' are received. The third receiving region 31''''-3 receives a sixth conductor 20f'''', which is designed as a waveguide I-pin bundle.In this embodiment, at least one collector (not shown in FIG. 7 ) is provided on both end sides of the stator. The (hollow) conductors 20a''''-20f'''' are electrically connected in series and hydraulically in parallel within a coil arrangement. The coolant can flow through from one end side of the stator to the respective other end side of the stator. In a further embodiment, a collector for deflecting the cooling liquid can be provided on one side, while at least one inlet and at least one outlet collector are attached on the opposite side.FIG. 8 shows a seventh embodiment of a stator, which has a stator package 30''''' and a receiving region 31'''''. In the receiving region 31'''', a first conductor 20a''''''a second conductor 20b''''''a third conductor 20c''''', and a fourth conductor 20d''''' are received.The first and second conductors 20a''''''-20b'''''' are designed as waveguides and the third conductor 20d''''' is designed as a waveguide bundle. In this exemplary embodiment, the fourth conductor 20 d"''' is designed as a bundle of parallel flat wires, wherein instead of a flat wire a bundle of forming wire or a pressed stranded wire can also be used. This is advantageous in particular in the case of electric motors with a power density design and a comparatively high electrical fundamental frequency, since waveguides cannot be made as small as a drawn wire and in particular stranded wire.With reference to the illustration in FIG. 9, a construction with waveguide pins with a large number of parallel channels will be explained clearly. This construction permits a relatively short individual channel length, low pressure losses in the cooling circuit and more effective cooling in comparison with known embodiments. However, the more layers of waveguides such a stator has, the more demanding it becomes to isolate them from one another over an air and creepage distance. The conductors 20' may be arranged as shown in Fig. 9.Furthermore, the embodiment shown in FIG. 9 has elevations / webs 45' in the region of a section of the collector 40' which are formed from an electrically insulating material. In FIG. 9, only a portion of the collector 40' is shown, which is closed by a cover or the like, for example. According to this exemplary embodiment, the section of the collector 40' has a circumferential groove, into which a sealing ring can be inserted for sealing with respect to the cover (not shown) of the samer. By increasing the air and creepage distance by means of the elevations 45' in the axial direction, a radially higher packing density, in particular an increase in the number of waveguide layers, is made possible, which leads to a better designed and more efficient electric machine.The embodiments described within the scope of the preceding embodiments can be used both in a radial flow machine and in an axial or transverse flow machine.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 119 405 A1

[0008] DE 10 2020 201 748 A1

[0009]

Claims

A stator comprising: - at least one coil unit having a plurality of conductors (20, 20'; 20a-20f - 20a''''''-20f'''''') comprising at least one waveguide, at least some conductors (20, 20x; 20'; 20a-20f - 20a''''''-20f'''''') being electrically connected in series to each other, and - a stator package (30-30''''') comprising at least one receiving region (31-31'; 31''-1, 31''-2; 31'''-1-31'''-2; 31''''-1, 31''''-2; 31''''-1, 31''''''-2, 31'''''''-3; 31'''''), wherein one or more conductors (20; 20a-20f - 20a''''''-20f'''''') are accommodated in the accommodation area, wherein the conductors (20, 20x; 20a-20f - 20a''''''-20f'''''') differ from one another at least partially.Stator according to claim 1, wherein the conductors differ in their shape and / or configuration when viewed in a cross section.The stator according to any one of the preceding claims, wherein the conductors differ in an external shape, in particular a width and / or height, a configuration as a hollow conductor or solid conductor, a configuration as an individual conductor or conductor bundle, and / or in the case of hollow conductors in a shape and / or a diameter of a channel.Stator according to one of the preceding claims, wherein all conductors are designed as waveguides, in particular as hollow conductor I pins.Stator according to one of the preceding claims, wherein the receiving regions (31', 31''''-1, 31''''-2) are designed with trapezoidal flanks and / or with stepped flanks.The stator according to any one of the preceding claims, wherein the conductors (20, 20x; 20a-20f - 20a''''''-20f'''''') have a first end portion and a second end portion arranged on different sides of the stator stack (30-30''''').Stator according to one of the preceding claims, wherein the receiving region (31-31'; 31"-1, 31"-2; 31"'-1-31"'-2; 31""-1, 31""-2; 31"""-1, 31"""-2, 31""-3, 31""""-2, 31"""-3; 31"""") is formed as a groove, and the conductors are arranged in the receiving region in such a way that a conductor arranged in the region of a groove base of the receiving region provides a higher fill factor than a conductor arranged closer to an air gap of the stator.The stator according to any one of the preceding claims, wherein one or more of the conductors are formed as conductor bundles.Stator according to one of the preceding claims, wherein end sections of the conductors (20, 20x; 20'; 20a-20f - 20a''''''-20f'''''') are connected, in particular in pairs, by means of a sleeve (15, 15x), wherein it is preferred that the sleeve (15, 15x) engages around the end sections of the conductors (20, 20x; 20'; 20a-20f - 20a''''''-20f'''''').A stator according to any preceding claim, wherein the conductors (20, 20x; 20'; 20a-20f - 20a''''''-20f'''''') have a rectangular cross-section.A stator according to any preceding claim, wherein the conductors (20, 20x; 20'; 20a-20f - 20a''''''-20f'''''') are connected to a collector.The stator of claim 11, wherein a collector is provided at an opposite end of the stator stack (30-30''''') and the conductors are hydraulically connected in parallel.The stator according to claim 11, wherein on a same side of the stator stack (30-30'''''), a collector for an inlet and an outlet of a coolant is arranged.A stator according to claim 11, 12 or 13, wherein the collector (40') comprises a boss (45') disposed between conductors.Stator according to one of Claims 11 - 14, wherein the collector is formed from a potting compound which extends at least in sections around the conductors.Stator according to one of the preceding claims, wherein the waveguide or waveguides are arranged in such a way that a fluid flows through the channels in parallel.Stator according to one of the preceding claims, wherein the stator package has a plurality of radially arranged receiving regions (31"-1, 31"-2; 31"'-1, 31"'-2; 31""-1, 31""-2; 31"""-1, 31"""-2, 31""-3), which are separated from one another by a web.Stator according to one of the preceding claims, wherein the coil unit has a helical or meander-shaped course.An electric machine comprising a stator according to any one of the preceding claims.Electric machine according to claim 19, comprising a rotor of internal rotor construction.Electric machine according to claim 19, comprising two rotors, in particular as a dual rotor with mechanical coupling of both rotors.Method for producing a stator, wherein the stator comprises at least one coil unit with a plurality of conductors (20, 20x; 20'; 20a-20f - 20a''''''-20f''''''), wherein at least one conductor is designed as a waveguide, wherein the conductors (20, 20'; 20a-20f - 20a''''''-20f'''''') differ at least partially from one another, comprising the steps of: providing a stator package (30-30''''') which has at least one receiving region (31-31'; 31''-1, 31''-2; 31'''-1-31'''-2; 31''''-1, 31''''-2; 31'''''-1, 31''''''-2, 31''''''-3; 31'''') and inserting the conductors (20, 20x; 20'; 20a-20f - 20a''''''-20f'''''') into the receiving region (31-31'; 31''-1, 31''-2; 31'''-1-31'''-2; 31''''-1, 31''''-2; 31''''-1, 31'''''-2, 31'''''-3; 31'''''''), the conductors being electrically connected to each other in series.

Images