Stator for electrical machine

Abstract

A stator for an electrical machine includes a stator core having a plurality of slots and a hairpin winding. The hairpin winding includes a hairpin conductor having two leg portions connected at a head portion. A leg portion of the hairpin conductor is received in the slot in at least two radially adjacent layers, a head portion extends out of the stator core at an insertion end, and an end section of the leg portion opposite the head portion extends out of the stator core at a weld end.

Description

Technical Field

[0001] The present application relates to a stator for an electric machine, the stator comprising a stator core having a plurality of slots and a hairpin winding. Background Art

[0002] With the continuous improvement of electrical and mechanical performance requirements, windings consisting of hairpin conductors with rectangular wire cross-sections have been realized, which provide higher slot filling rate and power density. The stator winding structure and the winding connection of the phase lead wire and the neutral wire are distributed to minimize the number of special-shaped hairpin conductors for ease of manufacturing.

[0003] CN 213782983 U relates to a flat wire hairpin stator structure and a motor. The flat wire hairpin stator structure comprises a stator core, a stator winding and a busbar. The stator core comprises an iron core body and a plurality of stator grooves, which are evenly spaced and formed on the circumferential wall surface of the inner side of the iron core body and extend in the axial direction of the iron core body; the stator winding comprises a multi-layer flat wire conductor inserted into each stator slot, one end of each layer of flat wire conductor is an insertion end, and the other end of each layer of flat wire conductor is a welding end; the multi-layer flat wire conductor is bent along the circumferential direction of the iron core body to form a U-phase winding, a V-phase winding and a W-phase winding in a surrounding mode. The conductor lead wires and the conductor neutral wire of each parallel branch of each phase winding are arranged at the welding end of the flat wire conductor. The busbars include a U-phase lead busbar, a V-phase lead busbar, a W-phase lead busbar and a neutral busbar arranged at the welding end of the flat wire conductor; the multi-layer flat wire conductor layout of the stator winding is simplified and the overall size of the flat wire hairpin motor is reduced.

[0004] CN 113809857 A discloses a multi-layer hairpin-type flat wire winding stator, which includes a stator core and a hairpin-type flat wire wave winding. The stator slots are arranged in the stator core, and the hairpin-type flat wire wave winding is embedded in the stator slots. The hairpin-type flat wire wave winding includes more than two branches. The stator slots where the three-phase windings of the hairpin-type flat wire wave winding are located are arranged in pairs and in sequence. After any branch has circled half a layer on the circumference, it is transposed to the equivalent slot of the adjacent stator slot, and when the branch is transposed to the equivalent slot of the adjacent stator slot in a cross-layer mode, a long-distance or short-distance connection is adopted, so that the head end and the tail end of any branch are located on the innermost layer and the outermost layer along the radial direction of the stator. Long-distance or short-distance connections only occur when the equivalent slots of adjacent stator slots are transposed across layers, so that the head and tail ends of the branch are located on the innermost and outermost layers in the radial direction of the armature, and a single branch of each phase can pass through the equivalent positions of all layers of all stator slots of the phase where the single branch is located.

[0005] CN 114172294 A discloses a flat wire motor and its outlet mechanism and winding mechanism, and the outlet mechanism includes a neutral row, the neutral row includes an arc plate arranged perpendicular to the winding axis of the flat wire motor and embedded in the end face of the winding; the terminal is arranged on the inner arc surface and the outer arc surface of the arc plate, and is used to connect with the winding, and the terminal is arranged on the inner arc surface and the outer arc surface in a staggered mode; the terminal includes a wiring main board arranged perpendicular to the plane where the arc plate is located; the access line is arranged in the middle of the wiring main board, away from one side of the arc plate, and is used to connect with the external wiring voltage; and the lead-out line is arranged at both ends of the wiring main board, and is used to connect with the winding. According to the flat wire motor and its outlet mechanism and winding mechanism, the design cost of the flat wire motor can be reduced.

[0006] CN 215300307 U discloses a flat wire winding structure and a stator and a motor including the flat wire winding structure, wherein the flat wire winding structure is arranged in a stator core, and a plurality of wire slots are provided in the tooth portion of the stator core. Each wire slot is provided with an even number of mounting positions arranged in a radial direction and is used to accommodate the pins of a plurality of flat wire coil conductors, the flat wire winding structure comprises a first phase winding, a second phase winding and a third phase winding, and each phase winding comprises four parallel branches; each of the first phase winding, the second phase winding and the third phase winding has a double-layer winding structure; and in the winding coils around the stator core, each parallel branch is introduced from the upper layer of a wire slot and led out from the lower layer of another wire slot, and two different parallel branches of the same phase winding overlap in the wire slot to form a double-layer winding structure. The motor provided by the utility model has good torque output performance and high power factor. Summary of the invention

[0007] One object is to provide a stator for an electrical machine with a stator core having a plurality of slots and a hairpin winding, wherein the hairpin winding has a scalable layout to improve the manufacture of various electrical machines.

[0008] This object is achieved by a stator for an electrical machine according to claim 1. Advantageous embodiments are subject to the dependent claims.

[0009] A stator for an electrical machine includes a stator core having a plurality of slots and a hairpin winding. The hairpin winding includes a hairpin conductor having two leg portions connected at a head portion, wherein a slot spacing between the two leg portions is defined by the head portion, and the slot spacing of each of the hairpin conductors is the same. The leg portions of the hairpin conductor are received in the slots in at least two radially adjacent layers, the head portion extends out of the stator core at an insertion end, and an end section of the leg portion opposite to the head portion extends out of the stator core at a welding end. The hairpin winding defines at least three phase windings, each phase winding having at least one branch, and each branch of each phase winding having a phase terminal formed at one of the end sections for connecting to a phase busbar, and a neutral terminal formed at one of the end sections for connecting to a neutral busbar. The phase terminal and the neutral terminal are all arranged at the welding end of the hairpin winding, in at least one of the outermost layer of the radially adjacent layers and the innermost layer of the radially adjacent layers.

[0010] An advantage of the stator is that the structure of the hairpin winding can be extended to electrical machines with different parameters, which are related to the number of layers per slot, the number of slots, the number of phase winding turns, the number of slots per pole and per phase, the number of parallel branches per phase, the number of poles and the number of phases. The same slot spacing of each of the hairpin conductors means that the hairpin conductors span the same number of slots in the circumferential direction of the slots and the same number of layers in the radial direction. The actual distance measurement between the two leg parts depends on the distance of the corresponding slots and layers, which increases in the radial direction. With all the phase terminals and neutral terminals arranged at the welding ends of the hairpin winding, the manufacturing process is enhanced because the welding operation for establishing contact with the corresponding busbar is performed in a limited area.

[0011] The hairpin conductor may be made of a wire having a rectangular cross section, such as a flat wire. The wire of the hairpin conductor is generally solid, but may also be hollow, for example to provide a cooling duct passing through the hairpin conductor. The leg portion and the head portion may be formed by bending the wire. The leg portion is received in different slots and in different layers of the stator core, and the slot spacing of the head portion spans the circumferential distance between two slots and the radial distance between two layers. The stator core has a generally cylindrical form defining a longitudinal axis, and any statements about the circumferential direction, the axial direction and the radial direction should be understood to be related to the longitudinal axis. The end sections of the branches are usually electrically interconnected by welding, and each branch forms a conductor, wherein one of the phase terminals is located at one end and one of the neutral terminals is located at the other end. The connected end sections of two consecutive hairpin conductors of the branch span the same slot spacing as the head portion. The neutral terminal can be connected to a single neutral busbar to form a star connection, or the neutral terminal of each phase winding pair can be connected to one of a plurality of neutral busbars to form a delta connection. Since the phase terminals and the neutral terminal are all arranged on the welded ends of the hairpin winding, the connection of the phase terminals and the neutral terminal is advantageously facilitated. In addition, the phase busbar and the neutral busbar can be arranged radially between the phase terminals and the neutral terminal in the outermost layer and the innermost layer, thereby reducing the overall axial length of the stator. A set of end segments forming the phase terminals and the neutral terminal can extend axially beyond a set of end segments forming an electrical interconnection, and the end segments can be welded together in pairs to form parallel branches of the phase winding. The neutral terminal of each branch is arranged in a layer opposite to the corresponding phase terminal of the branch in the radial direction. Therefore, each branch winding extends from the innermost layer or the outermost layer to the corresponding radially opposite layer starting at the phase terminal. The branch starting from the innermost layer is wound around the stator in a rotation direction opposite to the branch starting from the outermost layer.

[0012] According to an embodiment, the terminal connection range is defined by the circumferential sector of the stator occupied by the phase terminals and the neutral terminal on the welding end. The span of the terminal connection range on the circumference of the stator is minimized. This means that the phase terminals and the neutral terminal are arranged as closely together as possible to reduce the terminal connection range to the smallest possible span. The resulting minimum span depends on the number of poles of the stator and the number of slots per pole per phase.

[0013] According to another embodiment, the phase terminals are evenly divided between the outermost layer and the innermost layer. For example, the first half of the phase terminals are arranged in the outermost layer, and the second half of the phase terminals are arranged in the innermost layer. The advantage of distributing the phase terminals to the outermost layer and the innermost layer is that the phase terminals are concentrated within a limited circumferential range, thereby reducing the circumferential extension of the welding operation. In general, the number of branches per phase winding can be any natural number greater than zero. Those skilled in the art know that in the case of an odd number, the phase terminals cannot be evenly divided. In any case, the distribution of one phase terminal in the outermost layer and two phase terminals in the innermost layer or the distribution of two phase terminals in the outermost layer relative to three phase terminals in the innermost layer is still advantageous because the associated neutral terminal is always arranged in the corresponding relative layer of the phase terminals.

[0014] According to another embodiment, each phase winding has a plurality of parallel branches, and at least one pair of phase terminals of the parallel branches of at least one phase winding both extend from one common phase slot. Thus, if the phase winding has two parallel branches, one phase terminal is arranged in the outermost layer of the common phase slot, and the other phase terminal is arranged in the innermost layer of the common phase slot.

[0015] According to another embodiment, multiple pairs of phase terminals of the parallel branches of at least one of the phase windings extend in pairs from a plurality of adjacently arranged common phase slots. For example, if the phase winding has four or six branches, two or three phase terminals can be arranged in the outermost layer, and another two or three phase terminals can be arranged in the innermost layer, which are arranged in pairs in two or three common phase slots that can be arranged adjacently.

[0016] According to another embodiment, each phase winding has a plurality of parallel branches, wherein a first half of the phase terminals of the parallel branches of at least one of the phase windings extend from the innermost layer of at least one first offset phase slot, wherein a second half of the phase terminals of at least one phase winding extend from the outermost layer of at least one second offset phase slot, and wherein at least one first offset phase slot is circumferentially offset relative to at least one second offset phase slot. This embodiment is particularly beneficial for hairpin windings with an odd number of phase windings. If the parallel branches of at least one phase winding are concentrated in pairs in common phase slots and the parallel branches of at least one other phase winding are distributed circumferentially to the offset phase slots, the resulting distribution of the associated neutral terminals overlaps more closely with the phase terminals within a limited range of the circumference, thus again reducing the circumferential extension of the welding operation.

[0017] According to another embodiment, each phase winding has a plurality of parallel branches, wherein at least one pair of neutral terminals of the parallel branches of at least one of the phase windings both extend from one common neutral slot. Thus, for example, if the phase winding has two parallel branches, one neutral terminal is arranged in the outermost layer of the common neutral slot, and the other neutral terminal is arranged in the innermost layer of the common neutral slot. Furthermore, if the phase winding has more than two parallel branches, multiple pairs of neutral terminals of the parallel branches of at least one phase winding may extend in pairs from multiple adjacently arranged common neutral slots.

[0018] According to another embodiment, each phase winding has a plurality of parallel branches, wherein a first half of the neutral terminal of the parallel branches of at least one phase winding extends from the innermost layer of at least one first offset neutral slot, and wherein a second half of the neutral terminal of at least one phase winding extends from the outermost layer of at least one second offset neutral slot, and wherein at least one first offset neutral slot is circumferentially offset relative to at least one second offset neutral slot. Offsetting the neutral terminal of one phase winding in the circumferential direction to the first offset neutral slot and the second offset neutral slot has the advantage that one of the first offset neutral slot and the second offset neutral slot can be arranged between two common phase slots, resulting in a tighter overlap of the slots occupied by the phase terminal and the neutral terminal. It is known to those skilled in the art that the neutral terminal of one phase winding or either half of the phase terminals are offset, both having the same beneficial effect.

[0019] The slots occupied by the phase terminals and the neutral terminal are respectively a common phase slot, a first offset phase slot, a second offset phase slot, a common neutral slot, a first offset neutral slot, and a second offset neutral slot, which together define a terminal slot range that spans a portion of the total number of slots in the circumferential direction. The terminal slot range may span less than two-thirds of the total number of slots, preferably less than half of the total number of slots. The terminal slot range may further span a continuous range of adjacent slots in which at least one phase terminal or at least one neutral terminal is arranged.

[0020] According to another embodiment, each phase winding has a plurality of parallel branches, at least the phase terminal of the first branch and the neutral terminal of the second branch are arranged in one of the outermost layer and the innermost layer, wherein the first branch and the second branch are connected to the respective opposite one of the outermost layer and the innermost layer. This embodiment reduces the number of phase terminals and neutral terminals by connecting two branches, and allows the neutral terminal of the first branch and the phase terminal of the second branch to be arranged in the same layer. The connection of the phase terminal of the first branch and the neutral terminal of the second branch can be established by a jumper. The branches of each phase winding can be connected in pairs in this way. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Exemplary embodiments and other features and advantages will be illustrated with reference to the accompanying drawings, in which:

[0022] Figure 1A and 1B An embodiment of a stator for an electrical machine is shown in cross section;

[0023] Figure 2A and 2B Shows Figure 1A and 1B A magnified detail of the stator;

[0024] Figure 3 A hairpin conductor is shown;

[0025] Figure 4 The embodiment of Figure 1 is shown in a perspective view;

[0026] Figure 5 Shows Figure 4 Magnified details of

[0027] Figure 6 shows a general schematic diagram of the winding structure;

[0028] Figure 7 shows a general schematic diagram of a winding structure according to another embodiment;

[0029] Figure 8 shows a general schematic diagram of a winding structure according to another embodiment;

[0030] Fig. 9 An embodiment of a stator for an electrical machine is shown in perspective;

[0031] Fig.10 Shows Fig. 9 Magnified details of

[0032] Fig.11 An exploded view showing the busbars Fig. 9 Magnified details of

[0033] Fig.12 Shown in perspective Fig.11 Details;

[0034] Fig.13 An exemplary schematic diagram of a winding structure for a stator according to another embodiment is shown. DETAILED DESCRIPTION

[0035] exist Figure 1A , an embodiment of a stator 1 for an electrical machine is depicted in a schematic cross-sectional view in the direction of the longitudinal axis A. The stator core 2 has a plurality of slots 5 in which hairpin windings (see Figure 4 In the depicted embodiment, the stator core 2 comprises 48 slots 5 evenly distributed in the circumferential direction of the stator core 2. The leg portion of the hairpin conductor (see Figure 3) are received in the groove 5 in at least two radially adjacent layers Li, where i is an index representing the number Z of layers Li. Figure 1A The stator 1 comprises eight layers.

[0036] exist Figure 1B , another embodiment of a stator 1 is depicted in a schematic cross-sectional view in the direction of the longitudinal axis A. The stator core 2 further comprises 48 slots 5 evenly distributed in the circumferential direction of the stator core 2 , each slot 5 having four layers in this embodiment.

[0037] exist Figure 2A In the figure, the display is shown Figure 1A Detail of one of the slots 5. In the depicted embodiment, the leg portion 6 is received in the slot 5 in each of eight radially adjacent layers Li, L1 being the innermost layer and L8 being the outermost layer. More generally, for any number of z layers Li, the outermost layer is designated Lz.

[0038] exist Figure 2B In the figure, the display is shown Figure 1B Magnified detail of one of the slots 5. This embodiment has four radially adjacent layers Li occupied by the leg portions 6, L1 being the innermost layer and L4 being the outermost layer Lz.

[0039] exist Figure 3 , the hairpin conductor 4 is shown in detail. Figure 4 ) is composed of a plurality of hairpin conductors 4 having two leg portions 6 connected at a head portion 7, wherein the slot spacing is defined by the number of slots 5 spanned by the head portion 7. The slot spacing of each of the hairpin conductors 4 of the hairpin winding is the same. The two leg portions 6 of the hairpin conductor 4 are received in two different slots 5 and two different layers Li. The hairpin conductor 4 is depicted in the form it has when mounted on the stator 1. However, before assembly, the end section 8 is in line with the leg portion 6. After the hairpin winding is inserted into the slot 5, the end section 8 is bent.

[0040] exist Figure 41 , the stator 1 of FIG. 1 is shown in a perspective view. The head portion 7 of the hairpin conductor 4 extends out of the stator core 2 at the insertion end 9. The portion of the hairpin winding 3 extending at the insertion end 9 is also called the crown side. The end section 8 of the leg portion 6 opposite to the head portion 7 extends out of the stator core 2 at the welding end 10. The hairpin winding 3 is assembled outside the stator 1 and then inserted into the slot 5 from the insertion end 9. The end section 8 of the leg portion 6 is straight until it is inserted into the stator core 2, and is then bent into the depicted form, in which the end section 8 of the leg portion 6 in one slot 5 is bent alternately clockwise and counterclockwise layer by layer. The hairpin winding 3 defines three phase windings for the three phases U, V and W. Each phase winding has four parallel branches, which start at the phase terminals Un, Vn, Wn and end at the neutral terminals NUn, NVn, NWn. In the designation of the phase terminals and the neutral terminals, "U, V and W" identify the phases, and "n" is an index identifying the corresponding branch, i.e., 1 to 4 in this embodiment. The phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn are Figure 5 is fully specified and referenced in Figure 5 Detailed description. All phase terminals Un, Vn, Wn and neutral terminals NUn, NVn, NWn are arranged at the welding end 10. The hairpin conductors 4 forming one branch are electrically interconnected in series by spot welding at the end section 8. The end section 8 forming the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn extends axially beyond the end section 8 forming the spot weld electrical interconnection 16. The four phase terminals Un of the parallel branch of the U-phase winding are connected to the corresponding U-phase busbar 12, the phase terminal Vn of the V-phase winding is connected to the V-phase busbar 14, and the phase terminal Wn of the W-phase winding is connected to the corresponding W-phase busbar 15. The neutral terminals NUn, NVn, NWn are all connected to the neutral busbar 11, forming a star connection in this embodiment. The terminal connection range 17 is defined by the circumferential sector of the stator 1 occupied by the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn on the welding end 10. The terminal connection range 17 spans less than half of the circumference of the stator 1 , and in the present embodiment, spans one third of the circumference of the stator 1 .

[0041] exist Figure 5 middle, Figure 4 The welding end 10 is shown as an enlarged detail without the busbar. The arrangement of the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn is shown in FIG. Figure 5Described in full. The hairpin winding 3 defining the three-phase winding comprises four parallel branches for each phase U, V, W. The phase terminals are designated U1, U2, U3, U4, V1, V2, V3, V4, W1, W2, W3, W4, and the neutral terminals are designated NU1, NU2, NU3, NU4, NV1, NV2, NV3, NV4, NW1, NW2, NW3, NW4. The phase terminals designated U1, U2, V1, V2, W1, W2 and the neutral terminals designated NU3, NU4, NV3, NV4, NW3, NW4 are arranged in the outermost layer L8 of the radially adjacent layers Li, and the phase terminals designated U3, U4, V3, V4, W3, W4 and the neutral terminals designated NU1, NU2, NV1, NV2, NW1, NW2 are arranged in the innermost layer L1 of the radially adjacent layers Li. In the depicted embodiment, the phase terminals Un, Vn, Wn are evenly divided between the outermost layer Lz and the innermost layer L1. The phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn are densely arranged in a circumferential sector (terminal connection range 17) of the stator 1. The radially extending rows of end segments 8 correspond roughly to the 48 slots of the stator 1, provided that the end segments 8 are all bent the same radial distance in the clockwise and counterclockwise directions. Therefore, in this embodiment, the terminal connection range 17 spans 16 of the 48 slots 5, or spans a 120° circular sector of the stator 1. The terminal connection range 17 includes four slots 5 or rows, having an end segment 8 with a shorter spot-welded electrical interconnect 16, which is surrounded by longer phase terminals Un, Vn, Wn and neutral terminals NUn, NVn, NWn. All welding operations concerning the connection of the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn to the busbars 11 , 12 , 14 , 15 are limited to one third of the stator circumference.

[0042] Figure 6A general schematic diagram of the winding structure of a stator with arbitrary parameters is shown for the U, V and W phases. The upper matrix of each phase shows an exemplary branch of the corresponding phase winding, wherein the phase terminals Uk, Vk, Wk of the corresponding parallel branch number k are located in the outermost layer Lz, and the neutral terminals NUk, NVk, NWk of k said parallel branches are located in the innermost layer L1, where k is an integer between 1 and N / 2, and N is the total number of parallel branches of each phase winding. The lower matrix of each phase U, V, W shows another exemplary branch of the corresponding phase winding, wherein the phase terminals Ul, Vl, Wl of the parallel branch number 1 are located in the innermost layer L1, and the neutral terminals NUl, NVl, NWl of the parallel branch number 1 are located in the outermost layer Lz, where l is an integer between N / 2+1 and N. For any number of slots 5 and layers Li, the matrix represents slots 5 in columns and layers Li in rows to show that the proposed concept is modular and can be applied to a stator core with arbitrary parameters, provided that the parameters obey the conditions described below, where z is the number of layers and Qs is the number of stator slots 5.

[0043] The layers are designated Li, where i is the index from the innermost layer L1 to the outermost layer Lz. Thus, the matrix number i designates the row, i is an integer from 1 to z, i = [1, z]. The slots are designated Sj, where j is the index from S1 to SQs. Thus, the matrix number j designates the column, j is an integer from 1 to Qs, j = [1, Qs]. The number of phase terminals in the outermost layer Lz is k, where k = [1, N / 2]. The number of phase terminals in the innermost layer L1 is l, where l = [N / 2+1, N]. The number of layers z per slot is at least two, 2≤z, where z is an even integer. The number of pole pairs p is at least one, 1≤p, where p is an integer. The number of slots q per pole and per phase is at least one, 1≤q, where q is an integer. The number N of parallel branches per phase winding is between two and two times the number of slots per pole and per phase, 2≤N≤2q, where N is a positive factor of 2q. The number of phase windings Nph is calculated as Nph=(p*q*Z) / N. The number of phase windings m is at least three, m≥3, where m is an integer. The number of stator slots Qs follows the rule Qs=2p*m*q.

[0044] The U-phase branch of the upper matrix starts at the phase terminal Uk in the slot S1 in the outermost layer Lz. The hairpin connectors 4 are represented by arrows pointing to the slots and layers they span. The dotted lines of the arrows show that any number of slots and layers are spanned by the necessary number of hairpin windings 4. The branch terminates at the neutral terminal NUk in the slot SQ-(2*q) in the innermost layer L1. The U-phase branch of the lower matrix starts at the phase terminal U1 in the slot S1 in the innermost layer L1. The winding direction of the hairpin connector 4 has a rotation direction opposite to that of the branch of the upper matrix. The branch terminates at the neutral terminal NU1 in the slot S1+(3*q) in the outermost layer Lz. If the Figure 6The two branches of the U phase shown in FIG. 1 are installed in the stator core, then the slot S1 is one of the common phase slots 51 , the slot SQ-(2*q) is the first biased neutral slot 57 , and the slot S1+(3*q) is the second biased neutral slot 58 .

[0045] The V-phase branch of the upper matrix starts at the phase terminal Vk in the slot S1+(2*q) in the outermost layer Lz. The branch ends at the neutral terminal NVk in the slot SQ in the innermost layer L1. The V-phase branch of the lower matrix starts at the phase terminal Vl in the slot S1+(2*q) in the innermost layer L1. The branch ends at the neutral terminal NV1 in the slot S1+(5*q) in the outermost layer Lz. If two branches of the V phase are installed in the stator core, the slot S1+(2*q) is one of the common phase slots 51, the slot SQ is the first biased neutral slot 57, and the slot S1+(5*q) is the second biased neutral slot 58.

[0046] The W-phase branch of the upper matrix starts at the phase terminal Wk in the slot S1+(4*q) in the outermost layer Lz. The branch ends at the neutral terminal NWk in the slot S1+q in the innermost layer L1. The W-phase branch of the lower matrix starts at the phase terminal Wl in the slot S1+(4*q) in the innermost layer L1. The branch ends at the neutral terminal NW1 in the slot SQ-(4*q) in the outermost layer Lz. If the two branches of the W phase are installed in the stator core, the slot S1+(4*q) is one of the common phase slots 51, the slot S1+q is the first biased neutral slot 57, and the slot SQ-(4*q) is the second biased neutral slot 58.

[0047] The terminal slot range 18 of the winding structure spans from slot SQ-(4q) via slot S1 to slot S1+(4*q). No phase or neutral terminals extend from slots SQ-q and SQ-(3*q) at all, resulting in shorter spot weld electrical interconnections 16 by terminal connection range 17 ( Figure 4 ) is surrounded by the longer phase and neutral terminals. If the general winding pattern is applied to Figure 4 and Figure 5 In the exemplary embodiment of the embodiment of FIG. 1 , the windings depicted are windings starting at the phase terminals U1 , V1 , W1 and U3 , V3 , W3 , and the stator core 2 has the following parameters:

[0048] z = 8 layers per slot,

[0049] p = 4 pole pairs,

[0050] q = 2 slots per pole and per phase,

[0051] N = 4 parallel branches,

[0052] Nph = 32 series-connected phase winding turns,

[0053] k = 3 phases,

[0054] Qs = 48 slots.

[0055] exist Figure 7 In FIG. 1 , only a general schematic diagram of a winding structure according to another embodiment is depicted for the U phase. Figure 6 The names and conditions also apply to Figure 7 . However, this embodiment is provided for a stator having a number N of parallel branches that is less than twice the number of slots per pole and per phase, N<2q. The branch starts at the phase terminal Uk in the slot S1 in the outermost layer Lz and completes the winding around the innermost layer L1 in the slot SQ-(2*q), but does not end there. Instead, the end section 8 extending from the slot SQ-(2*q) is connected to the first end of the jumper 19, which is connected at its second end to the end section 8 extending from the slot S1 in the innermost layer L1. From there, the branch changes the direction of rotation of the winding direction of the hairpin connector 4 and ends at the neutral terminal NUk in the slot S1+(3*q) in the outermost layer Lz. In this embodiment, all phase terminals Un of the branches of each phase can be introduced only through the outermost layer Lz, and the corresponding neutral terminal NUn is led out in the same layer (outermost layer Lz). In the innermost layer L1, the configuration of the jumper 19 allows parallel connections to redistribute the output of the branch towards the input layer. A person skilled in the art knows that the phase terminals Un and the corresponding neutral terminals NUn can also be arranged alternately in the innermost layer L1, wherein the connection via the jumper 19 is then realized in the outermost layer Lz.

[0056] exist Figure 8 , a general schematic diagram of a winding structure according to another embodiment is shown, wherein the terminal connection range 17 ( Fig. 9 ) is minimized. Figure 6 The names and conditions also apply to Figure 8 . U phase and V phase and Figure 6 The embodiment of is the same and is not described again. This embodiment differs only in the W phase, but this difference is applicable to any of the phases.

[0057] The W-phase winding has multiple parallel branches, two of which are depicted, one in the upper matrix and one in the lower matrix. In the upper matrix, the phase terminal Wk extends from the slot S+(4*q) in the outermost layer Lz, and the neutral terminal NWk extends from the slot S1+q in the innermost layer L1. In the lower matrix, the phase terminal W1 extends from the slot SQ-q in the innermost layer L1, and the neutral terminal NW1 extends from the slot S1+q in the outermost layer Lz. The phase terminal Wk extends from the first biased phase slot 52 and the phase terminal Wl extends from the second biased phase slot 53. The first biased phase slot 52 is circumferentially offset relative to at least one second biased phase slot 53. However, both neutral terminals NWk, NWl extend from a common neutral slot 56. As shown Fig. 9 As can be seen in FIG. 1 , by offsetting half of the phase terminals of at least one phase, the resulting structure does not enclose any of the shorter spot welded electrical interconnections 16 between the longer phase and neutral terminals in the terminal connection range 17 .

[0058] exist Fig. 9 , another embodiment of a stator 1 for an electrical machine is shown in a perspective view. The end section 8 extending from the stator core 2 at the welding end 10 is straight until it is inserted into the stator core 2 and is then bent into the depicted form, the end section 8 being bent alternately clockwise and counterclockwise layer by layer. The hairpin winding 3 defines three phase windings for the three phases U, V and W. Each phase winding has four parallel branches starting at the phase terminals Un, Vn, Wn and ending at the neutral terminals NUn, NVn, NWn, which will be referred to as Fig.10 Detailed description.

[0059] exist Fig.10 In the Fig. 9 Magnified details of. Describe together Fig. 9 and Fig.10. All phase terminals Un, Vn, Wn and neutral terminals NUn, NVn, NWn are arranged at the welding end 10. The hairpin conductors 4 forming one branch are electrically interconnected in series by spot welding at the end section 8. The end section 8 forming the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn extends axially beyond the end section 8 forming the spot weld electrical interconnection 16. The four phase terminals Un of the parallel branch of the U-phase winding are connected to the corresponding U-phase busbar 12, the phase terminal Vn of the V-phase winding is connected to the V-phase busbar 14, and the phase terminal Wn of the W-phase winding is connected to the corresponding W-phase busbar 15. The neutral terminals NUn, NVn, NWn are all connected to the neutral busbar 11, forming a star connection in this embodiment. The terminal connection range 17 is defined by the circumferential sector of the stator 1 occupied by the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn on the welding end 10. The terminal connection range 17 spans one quarter of the circumference of the stator 1, or 12 of the 48 slots. The span of the terminal connection range 17 is minimized and is therefore smaller than Figure 4 More compact than depicted in .

[0060] The hairpin winding 3 defining the three-phase winding comprises four parallel branches for each phase U, V, W. The phase terminals are designated U1, U2, U3, U4, V1, V2, V3, V4, W1, W2, W3, W4, and the neutral terminals are designated NU1, NU2, NU3, NU4, NV1, NV2, NV3, NV4, NW1, NW2, NW3, NW4. The phase terminals designated U1, U2, V1, V2, W1, W2 and the neutral terminals designated NU3, NU4, NV3, NV4, NW3, NW4 are arranged in the outermost layer L8 of the radially adjacent layers Li, and the phase terminals designated U3, U4, V3, V4, W3, W4 and the neutral terminals designated NU1, NU2, NV1, NV2, NW1, NW2 are arranged in the innermost layer L1 of the radially adjacent layers Li. In the depicted embodiment, the phase terminals Un, Vn, Wn are evenly divided between the outermost layer Lz and the innermost layer L1. The phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn are densely arranged in a circumferential sector (terminal connection range 17) of the stator 1. The radially extending rows of end segments 8 correspond roughly to the 48 slots of the stator 1, provided that the end segments 8 are all bent the same radial distance in the clockwise and counterclockwise directions. Therefore, in this embodiment, the terminal connection range 17 spans 12 of the 48 slots, or spans a 90° circular sector of the stator 1. The terminal connection range 17 does not include any slots or rows of end segments 8 with shorter spot weld electrical interconnections 16. All welding operations on the connection of the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn to the busbars 11, 12, 14, 15 are limited to within one quarter of the stator circumference.

[0061] exist Fig.11 In the exploded view, the Fig. 9 , which has a neutral busbar 11, a U-phase busbar 12, a V-phase busbar 14 and a W-phase busbar 15. Fig.12 In the perspective drawing, Fig.11 Detail of a hairpin winding 3 in which the neutral busbar 11, the U-phase busbar 12, the V-phase busbar 14 and the W-phase busbar 15 are in their respective final positions when mounted on the welding end 10 of the hairpin winding 3.

[0062] exist Fig.13 In, an example of a schematic diagram of a winding structure for another embodiment of a stator is shown. The assignment of the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn of the hairpin winding to the slots 5 of the stator is described. The matrix represents the slots 5 in columns and the layers L1 to L8 in rows. In the top row, the slot numbers 1 to 48 are specified. In the left column, the layer names L1 to L8 are given. The matrix is ​​divided into three parts according to the number of slots, which are understood in a continuous order. The notation of the matrix elements shows the route of each branch through the slots and layers. For the branches of the U phase, the notation is given in the form of "Ux_y", for the branches of the V phase, in the form of "Vx_y", and for the branches of the W phase, in the form of "Wx_y", where x specifies the number of branches and y specifies the continuous count from the corresponding phase terminal Un, Vn, Wn of each branch to the corresponding neutral point terminal NUn, NVn, NWn. Therefore, in slots 1 and 2, the matrix elements with the four phase terminals of the U phase are designated as U1_1, U2_1 in the outermost layer L8 and U3_1, U4_1 in the innermost layer L1. In slots 5 and 6, the four phase terminals of the V phase are designated as V1_1, V2_1 in the outermost layer L8 and V3_1, V4_1 in the innermost layer L1, respectively. In slots 9, 10, 45 and 46, the four phase terminals of the W phase are designated as W1_1, W2_1 in the outermost layer L8 and W3_1, W4_1 in the innermost layer L1, respectively.

[0063] The structure of the hairpin winding 3 is described by taking the first branch of the U phase as an example. The leg portion 6 (see Figure 3) is arranged in slot No. 1 in the outermost layer L8, which has the matrix element label U1_1. A second leg portion 6 of the same hairpin conductor 4 is found in the adjacent negative pole of the U-phase winding, in slot No. 7 in the adjacent layer L7, which has the matrix element label U1_2. The distance from slot No. 1 of layer L8 to slot No. 7 of layer 7 is the slot spacing of the hairpin conductor 4. For all hairpin conductors 4 of the hairpin winding 3, the slot spacing of six slots 5 in the circumferential direction and one layer Li in the axial direction is the same. The route of the first branch of the U-phase winding is further described by way of example. The end section 8 of the leg portion 6 designated as U1_2 is spot welded on a welding end 10 to a subsequent second hairpin conductor 4, which is designated as slot No. 13 in the next positive pole of the U-phase winding, U1_3 in the outermost layer L8, and slot No. 19 in the next negative pole of the U-phase winding, U1_4 in the adjacent layer L7. The rear end section 8 of the leg portion 6 is spot welded to the third hairpin conductor 4, which has the mark U1_5 (slot No. 25, layer L8) positive pole, and U1_6 (slot No. 31, layer L7) negative pole, etc. It should be noted that the slot spacing of six slots in the circumferential direction and one layer Li in the axial direction is also spanned by the bent end section 8 on the weld end 10, wherein the two end sections 8 of each weld pair 16 are offset by half the slot spacing (see Fig. 9 ). The fourth hairpin conductor 4 returns to the negative U phase pole, with the leg portion designated as U1_8 in slot number 43. The second winding around the stator core 2 starts again with the fifth hairpin conductor 4 in slot number 1, now in the next layer L6, marked as U1_9. The branch continues, now oscillating between layers L6 and L5, changing to layers L4 and L3 after further complete winding around the stator core 2. The final winding in the inner layers L2 and L1 ends with the sixteenth hairpin conductor 4 of the branch. The mark U1_32 indicates the position of the leg portion 6 with the neutral terminal NU1 at its end section 8 in slot number 43 in the innermost layer L1. It should be noted that the neutral terminal NU1 is not located at the circumferential position of slot number 43, but at the circumferential position of slot number 46 due to its offset by half the slot spacing. It should also be noted that the end section 8 of the phase terminal U1 of the same branch in the outermost layer L8 is offset in the opposite direction, and therefore also has a circumferential position of slot No. 46.

[0064] For the other branches having phase terminals U2, V1, V2, W1, W2 in the outermost layer L8, they are arranged parallel to the above branches starting in slots No. 2, No. 5, No. 6, No. 9 and No. 10 respectively. The slot spacing of the hairpin conductors 4 is the same. The branches terminating at the neutral terminals NU3, NU4, NV3, NV4, NW3, NW4 in the outermost layer L8 must also be arranged in parallel to avoid crossing branches and provide a uniform slot spacing of the hairpin conductors 4. Therefore, the branches starting at the phase terminals U3, U4, V3, V4, W3, W4 in the innermost layer L1 are wound around the stator core 2 in the opposite direction of rotation to the branches having the phase terminals U1, U2, V1, V2, W1, W2 in the outermost layer L8. Starting from the innermost layer L1, the branches are arranged towards the slots with downward consecutive numbering. For example, the third branch of the W-phase winding starts with the phase terminal W3 in the slot number 45 in the innermost layer L1, designated as W3_1. The second leg portion 6 of the same hairpin conductor 4 is located in the adjacent negative pole of the W-phase winding in the slot number 39 in the adjacent layer L2, where the matrix element is marked as W3_2. The distance from the slot number 45 of the L1 layer to the slot number 39 of the 2nd layer is the uniform slot spacing of the hairpin conductor 4 of six slots in the circumferential direction and one layer Li in the axial direction. Therefore, all branches are arranged in parallel, with the phase terminals Un, Vn, Wn and the neutral terminals NUn, NVn, NWn evenly distributed to the innermost layer L1 and the outermost layer L8.

[0065] The phase terminals Un, Vn extend in pairs from the slots, which are called common phase slots 51. The phase terminals U1 and U3 extend from the common phase slot 51 having a slot number of 1. However, it is known to those skilled in the art that the phase terminals Un, Vn extending in pairs from the common phase slot 51 will not be arranged in the same row on the welding end 10 because the end segment 8 in the outermost layer L8 is bent in a rotation direction opposite to the end segment 8 in the innermost layer L1. In the depicted embodiment, the phase terminals U1 and U3 have a corresponding offset of six rows or slots (i.e., the slot spacing of the hairpin conductor) in the circumferential direction. In the depicted embodiment, multiple pairs of phase terminals Un, Vn of the parallel branches extend in pairs from multiple adjacently arranged common phase slots 51. The common phase slots 51 of the U-phase winding are slots 1 and 2, and the common phase slots 51 of the V-phase winding are slots 5 and 6. The phase terminal Wn of the W-phase winding is biased, W1 and W2 extend from slots No. 9 and No. 10 referred to as the first bias phase slot 52 , and W3 and W4 extend from slots No. 45 and No. 46 referred to as the second bias phase slot 53 .

[0066] The neutral terminals NU1, NU2, NV1, NV2 of the parallel branches of the respective phase windings U, V extend from the first offset neutral slot 57 from the innermost layer L1, and the neutral terminals NU3, NU4, NV3, NV4 extend from the second offset neutral slot 58 from the outermost layer LZ. The first offset neutral slot 57 is circumferentially offset relative to the second offset neutral slot 58. The first offset neutral slot 57 of the U-phase winding is slot No. 43 and slot No. 44, which are offset relative to the second offset neutral slot 58 of the U-phase winding in slot No. 7 and slot No. 8. The first offset neutral slot 57 of the V-phase winding is slot No. 47 and slot No. 48, which are offset relative to the second offset neutral slot 58 of the V-phase winding in slot No. 11 and slot No. 12. The offset is twelve slots in each case. The neutral terminals NW1 , NW2 , NW3 , NW4 of the W-phase winding extend from a common neutral slot 56 , which is slots 3 and 4 in this embodiment.

[0067] The common phase slot 51, the common neutral slot 56, the first offset neutral slot 57, the second offset neutral slot 58, the first offset phase slot 52, and the second offset phase slot 53 together define a terminal slot range 18 that spans a portion of the total number of slots in the circumferential direction. In the present embodiment, the terminal slot range 18 spans from slot No. 43 to slot No. 12, i.e., spans 18 slots. The slots of the terminal slot range are not occupied by the non-terminal end sections 8 in the outermost layer L8 or the innermost layer L1. Calculated in terms of slots, the terminal slot range 18 is larger than the terminal connector range 17 by six slots of the hairpin connector slot spacing (compare Fig. 9 ).

[0068] Reference Numbers

[0069] 1 Stator

[0070] 2 Stator core

[0071] 3 Hairpin Winding

[0072] 4 Hairpin conductor

[0073] 5 slots

[0074] 51 Public phase slot

[0075] 52 First bias phase slot

[0076] 53 Second bias phase slot

[0077] 56 Public neutral slot

[0078] 57 First bias neutral slot

[0079] 58 Second bias neutral slot

[0080] 6 Legs

[0081] 7 Head

[0082] 8 End section

[0083] 9 Insertion end

[0084] 10 Welding end

[0085] 11 Neutral bus

[0086] 12 U-phase busbar

[0087] 14 V phase busbar

[0088] 15 W-phase busbar

[0089] 16 Spot welding interconnection

[0090] 17 terminal connector range

[0091] 18 Terminal slot range

[0092] 19 Jumper

[0093] A Longitudinal axis

[0094] Li layer

[0095] U, V, W phase winding

[0096] Un phase terminal, U phase winding

[0097] Vn phase terminal, V phase winding

[0098] Wn phase terminal, W phase winding

[0099] NUn neutral terminal, U phase winding

[0100] NVn neutral terminal, V phase winding

[0101] NWn neutral terminal, W phase winding.

Claims

1. A stator (1) for an electrical machine, comprising: A stator core (2) having a plurality of slots (5) and a hairpin winding (3); wherein the hairpin winding (3) comprises a hairpin conductor (4) having two leg portions (6) connected at a head portion (7), wherein a slot spacing between the two leg portions (6) is defined by the head portion (7), and the slot spacing of each of the hairpin conductors (4) is the same; wherein the leg portion (6) of the hairpin conductor (4) is received in the slot (5) in at least two radially adjacent layers (Li), the head portion (7) extends out of the stator core (2) at an insertion end (9), and an end section (8) of the leg portion (6) opposite to the head portion (7) extends out of the stator core (2) at a welding end (10); wherein the hairpin winding (3) defines at least three phase windings (U, V, W), each phase winding having at least one branch, each branch of each phase winding having a phase terminal (Un, Vn, Wn) formed at one of the end sections (8) for connection to a phase busbar, and a neutral terminal (NUn, NVn, NWn) formed at one of the end sections (8) for connection to a neutral busbar, The phase terminal and the neutral terminal are all arranged at the welding end (10) of the hairpin winding (3), in at least one of the outermost layer (Lz) of the radially adjacent layers (Li) and the innermost layer (L1) of the radially adjacent layers (Li).

2. The stator according to claim 1, wherein: The terminal connection range (17) is defined by the circumferential sector of the stator (1) occupied by the phase terminals (Un, Vn, Wn) and the neutral terminals (NUn, NVn, NWn) on the welding end (10), and wherein the span of the terminal connection range (17) on the circumference of the stator (1) is minimized.

3. A stator according to any one of the preceding claims, wherein: Each phase winding has a plurality of parallel branches, and at least one pair of phase terminals (Un, Vn, Wn) of the parallel branches of at least one phase winding both extend from a common phase slot (51).

4. The stator according to claim 3, wherein: A plurality of pairs of phase terminals (Un, Vn, Wn) of the parallel branches of the at least one phase winding extend in pairs from a plurality of adjacently arranged common phase slots (51).

5. A stator according to any one of the preceding claims, wherein: Each phase winding has a plurality of parallel branches, and wherein a first half of the phase terminals (Un, Vn, Wn) of the parallel branches of at least one phase winding extend from an innermost layer (L1) of at least one first offset phase slot (52), and wherein a second half of the phase terminals (Un, Vn, Wn) of the at least one phase winding extend from an outermost layer (LZ) of at least one second offset phase slot (53), and wherein the at least one first offset phase slot (52) is circumferentially offset relative to the at least one second offset phase slot (53).

6. A stator according to any one of the preceding claims, wherein: Each phase winding has a plurality of parallel branches, and wherein at least one pair of neutral terminals (NUn, NVn, NWn) of the parallel branches of at least one of the phase windings both extend from a common neutral tank (56).

7. The stator according to claim 6, wherein: A plurality of pairs of neutral terminals (NUn, NVn, NWn) of the parallel branches of the at least one phase winding extend in pairs from a plurality of adjacently arranged common neutral slots (56).

8. A stator according to any one of the preceding claims, wherein: Each phase winding has a plurality of parallel branches, and wherein a first half of the neutral terminals (NUn, NVn, NWn) of the parallel branches of at least one phase winding extend from the innermost layer (L1) of at least one first biased neutral slot (57), and wherein a second half of the neutral terminals (NUn, NVn, NWn) of the at least one phase winding extends from the outermost layer (LZ) of at least one second biased neutral slot (58), and wherein the at least one first biased neutral slot (57) is circumferentially offset relative to the at least one second biased neutral slot (58).

9. The stator according to claim 3 and claim 6, wherein: The common phase slot (51), the first biased phase slot (52), the second biased phase slot (53), the common neutral slot (56), the first biased neutral slot (57) and the second biased neutral slot (58) together define a terminal slot range that spans a portion of the total number of slots (5) in the circumferential direction.

10. A stator according to any one of claims 6 to 9, wherein: The terminal slot range spans a continuous range of adjacent slots (51, 52, 53, 56, 57, 58) in which at least one phase terminal or at least one neutral terminal is arranged.

11. A stator according to any one of the preceding claims, wherein: Each phase winding has a plurality of parallel branches, at least the phase terminal of the first branch and the neutral terminal of the second branch are arranged in one of the outermost layer (Lz) and the innermost layer (L1), wherein the first branch and the second branch are connected to a corresponding opposite one of the outermost layer (Lz) and the innermost layer (L1).

12. The stator according to claim 1, wherein: The phase terminals (Un, Vn, Wn) are evenly divided between the outermost layer (Lz) and the innermost layer (L1).

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