Highly configurable stator or rotor winding and stator or rotor using such winding

Abstract

The present invention relates to a highly configurable stator or rotor winding and a stator or rotor using such winding, in which single layer hairpins with different pitches are used in at least two positions in the slots, such an arrangement allows for a wider group of windings and therefore an electrically balanced stator or rotor, preferably while maintaining the air gap diameter, number of slots, and conductor dimensions.

Description

[Technical Field]

[0001] The present invention relates to highly configurable stator or rotor windings and to stators or rotors using such windings. [Background technology]

[0002] It is generally known to provide a stator or rotor for an electric machine, such as a generator or motor, for example for hybrid electric vehicle (HEV) applications, in which the stator or rotor winding (single-phase or multi-phase) consists of a plurality of bar conductors bent together and interconnected in various ways to obtain an electrical winding, also known as a "bar winding." Such bent bar conductors are also called "hairpin conductors" or simply "hairpins." A bar winding may consist of one or more groups of concentric windings, sometimes called "crowns," each of which is itself a winding ("winding set"). In turn, each crown may consist of one or more layers, and as described below, a winding may therefore consist of one or more bar layers. Each layer may have an entire series of bar conductors or may consist of bar conductor portions spanning two or more layers.

[0003] In particular, windings with hairpins having circular cross sections (also called "round wire conductors") or rectangular cross sections, or conductors whose cross-sectional shape varies along their length (e.g., a round conductor with a rectangular portion received in a slot), are also known in the prior art. In this regard, a "rectangular" or "square" conductor winding refers herein to a winding having four substantially flat sides, each joined to an adjacent side by a generally rounded edge. Bar conductors having a trapezoidal cross section are also known.

[0004] The aforementioned bar conductors are typically preformed by starting from a straight bar conductor and bending it into a "U" or "P" shape. U.S. Patent No. 7,480,987 describes an example of a method for preforming a straight bar conductor to form a hairpin. A "U"- or "P"-shaped preform conductor, often referred to in the art as a "preform base conductor," generally has two adjacent legs of equal or unequal length, each having a free end and an opposite end connected to the other of the two legs by a bridge-like connection. Because the ends protrude when inserted into a rotor or stator, they are hereinafter referred to as "free protrusions" and "opposite connecting protrusions." The connecting protrusions may also be referred to as "heads" or "bridge-like connections." The assembly of the "heads" of the same hairpin legs forms a so-called "bridge-like connection," "bridge connection," or "hairpin head."

[0005] 1(a), a hairpin 255 is preformed from a linear hairpin (not shown) by bending it to form a first leg 255a having respective free protruding ends 255aE and a second leg 255b having respective free protruding ends 255bE. The bending simultaneously forms a bridge-like connection 255c between the two legs 255a, 255b. In this example, the preformed hairpin is in the shape of a flattened "U." For example, it is known to apply two different types of twists to "U"- or "P"-shaped preformed hairpins to form stators for electric machines.

[0006] The stator core or rotor core of a radial-flux electric machine is essentially a ring with two flat and two cylindrical surfaces, with the generator perpendicular to the two flat surfaces parallel to the rotation axis of the rotor of the electric machine. Hereinafter, radial, circumferential, and axial directions refer to the latter axis unless otherwise specified. One of the two cylindrical surfaces is at least partially adjacent to the air gap of the electric machine to which the stator or rotor belongs and defines a series of slots in which straight sections of the windings are accommodated. The two flat surfaces are divided into an insertion surface or insertion side and a surface or side opposite the insertion side (welding side). The portions of the windings protruding from the core are called headers. The free ends of the conductors belong to the header protruding from the side opposite the insertion side, and most of these are subject to welding. If the windings have protruding sections that are connected in a bridge-like manner to the legs inserted into the stator slots, they belong to the header protruding from the insertion side. The protruding sections from the insertion side, whether free or bridge-like, will be referred to as the "protruding sections from the insertion side" below.

[0007] The area of ​​the stator or rotor core between one slot and the adjacent slot is called a tooth. The number of teeth is equal to the number of slots. The part of the core where the teeth connect is called a yoke. The yoke defines a portion of each slot and is positioned relative to the slot opening on the air gap of the machine.

[0008] The slots may be divided into arrays at each location where a leg of a base conductor may be placed. Conductors (or conductor portions) housed in the same radial location as a slot define a so-called winding layer. The set of slots closest to the axis of the (stator or rotor) array is generally called the "proximal layer," while the set of slots furthest from the axis of the (stator or rotor) array is generally called the "distal layer."

[0009] In the first type of twisting, also called "insertion-side twisting," preformed elementary conductors are suitably inserted into corresponding radially aligned pockets or "slots" provided in a twisting device adapted to deform such conductors after insertion. After the conductors are withdrawn from the twisting device, the twisting device is essentially used to spread the legs of a "U" or "P" shape so that the two legs of each conductor can be inserted into a corresponding pair of slots in the stator core, the slots being angularly offset from one another by a predetermined distance substantially equal to the angular distance between the slots into which the legs are inserted and radially spaced apart by the radial distance between the slot positions occupied by the legs.

[0010] Starting from a preform hairpin such as that shown in FIG. 1(a), a hairpin suitable for insertion into a stator (or rotor) can be formed by spreading the legs 255a and 255b and forming a bridge-like connection 255c, resulting in the shape shown in FIG. 1(b). Reference numeral 255p denotes the pitch of the hairpin, i.e., the linear or angular distance between the legs, or the slot pitch, or more generally, the distance in terms of "volume units." It should be noted that in this case, the central apex 255c2 of the formed hairpin is a base conductor whose cross section is rotated 180° with respect to the central plane of the hairpin (an ideal plane passing through the inside of the hairpin and containing the two legs). Such a rotation is useful in some twisted hairpins, as defined below, for the purpose of reducing eddy currents circulating through the ends of layers when they are welded together by interchanging the layers (slot positions interchanged) compared to when the same layers run parallel to each other without exchanging slot positions.

[0011] Patent application published as US2009 / 0178270 describes an example of an insertion-side twisting method in which a preformed bar pin is inserted into a pocket of a twisting device and then twisted at a uniform pitch, the hairpin having a rectangular cross section.

[0012] According to the prior art, referring to Figure 2, hairpins can also be obtained by molding, a process in which a straight conductor is pressed into a cone with a punch and die type system. Figure 2(a) shows such a molded conductor, where the conductor does not have a cross section that rotates relative to the central plane of the hairpin.

[0013] This formed hairpin or the preformed and expanded hairpin obtained as described above can also be subjected to so-called "weld side twisting", in which case it is possible to introduce a "step-like" shape into the protruding portions of the legs 255a and 255b, for example, as shown in Figure 2(b), the leg 255a has a first straight portion 255a1, a step-like portion 255a2, and a second straight portion 255a3 (which substantially corresponds to portion 255aE in Figure 1).

[0014] Referring to FIG. 3, the shape of the insertion protrusion or bridge-like connection 255c for the shaped hairpin may have three portions 255c1, 255c3, and 255c2, starting at the connection with the second leg 255b and ending at the connection with the first leg 255a (not visible in FIG. 3). Portion 255c1 has a main extension direction B and a radius of curvature RB, portion 255c3 has a main extension direction A and a radius of curvature RA, and portion 255c2 has a main extension direction C (and possibly its curvature, not shown). Portion 255c2 will be referred to below as a "layer-changing bend," which effectively causes the head and legs of the hairpin to be in different layers when inserted into their respective slots in the stator pack. Reference symbol α1 denotes the angle between directions A and C, reference symbol α2 denotes the angle between directions A and B, and reference symbol α3 denotes the angle between directions B and C, which is equal to the sum of angles α1 and α2. This is only one final possible shape of the hairpin, all other shapes with different portions and shapes of both the bridge and the legs can be used with the devices and methods according to the present specification.

[0015] There are also conductors defined as "reverse" conductors (not shown), which are hairpins whose bend direction at the bridge-like connection is opposite to that of most of the hairpins forming the same winding, and which are used to pass from the last layer of a crown to the first layer of the next crown.

[0016] Referring further to FIG. 4A, there is a twisted hairpin with a cross-section that is inverted at the bending point (FIG. 4A(a)), causing the layers to swap positions. As can be seen from the type of hatching in the cross-section of FIG. 4A(a), this inversion, or swap of positions, results in the upper layer of the pair in the left slot being underneath the other layer in the right slot. In other hairpin configurations, the transposition can be continuous along the portion of the hairpin housed in the slot (FIG. 4A(b); US 3,837,072). The variation shown in FIG. 4B is a twisted hairpin without inversion, as shown in U.S. Pat. No. 8,552,611 B2. FIG. 4C (taken from FIG. 6 of U.S. Pat. No. 6,894,417 B2) shows variations in the leg arrangement of twisted hairpin 255-S in a double-crown winding with different slot positions. References A and B indicate the crowns to which the legs (belonging to different hairpins) indicated in the slots belong.

[0017] 4D (obtained from US10749399B2), there are also so-called "inverted hairpins" 255-IP, i.e., hairpins formed by spreading the legs (rather than the insertion-side twisting method described above) or by a "press and die" system, characterized in that the legs in each slot occupy the same radial position (generally referred to as "single-layer hairpins"), i.e., belong to the same layer. Therefore, usually (except in the case of reverse twisting at the inner and outer crowns), both ends of the twisted side of the single-layer hairpin are bent in the same direction. In fact, the part protruding from the bridge-like connection side can be bent in the same tangential direction or can have a V-shape. At least two layer-changing bends are required at the connection part.

[0018] Finally, there are pairs of hairpins 255-AC, whose homologous legs belong to different layers (FIG. 4E(a)) or the same layer (FIG. 4E(b)), and which are configured and dimensioned to be nested (regardless of the difference in pitch (or "volume units") between the nested elements). The nested conductors are each smaller than the other, so that one is inside the other. Therefore, the most appropriate English term seems to be "nested hairpins," and in any case, the configuration is clear from the drawings.

[0019] In the following, all of the hairpins described above, and any other hairpins having any number of legs and coupled together, will be included under the term "basic conductor."

[0020] After being subjected to the first type of twisting or forming, the base conductors are generally pre-assembled into winding sets as described above. The pre-assembly device generally differs from the twisting device in that it has a series of slots into which the legs of each hairpin are inserted, the number of which is equal to the number of slots in the stator associated with the windings.

[0021] The winding sets are then inserted en bloc into slots in the stator core through the first side of the core (the so-called "insertion side" or "insertion face") with their free portions protruding from a second, opposite side (the so-called "weld side" or "connection side" or "weld face" or "flank face"). Systems for transporting and inserting windings into stator packs are also known.

[0022] Depending on the particular winding pattern to be achieved, the free portions of the base conductors protruding from the opposite side to the insertion side may be subjected to a second type of twisting, also called "weld-side twisting," after being inserted, for example, into pockets made in a suitable twisting device. Here, the twisting device bends or twists the free portions of the conductors in order to properly shape them and thereby obtain a proper electrical connection between the conductors for completing the winding. Patent application published under US2009 / 0302705 describes an example of a method for weld-side twisting of the type mentioned above.

[0023] The prior art provides various types of windings. However, windings often use special connections such as "jumpers" and / or the equipment for making them differs significantly from one another. An example of a jumper is shown in FIG. 4F, where different conductors 255 arranged at least partially on the same layer are connected to one another by a jumper 270, which should be understood as a special connection. Jumpers are usually made with welded connections, which can be of various types. In other words, some winding types require significant changes in manufacturing equipment.

[0024] Therefore, there is a need for a polyphase winding pattern that allows the number of parallel paths to be simply changed without changing the components (typically hairpins) that form the windings and without adding special connections. Such flexibility should occur without compromising the correct placement of the base conductors in the stator slots, i.e., the electrical balance of the various parallel paths.

[0025] To illustrate this situation of electrical balance, we present an example of a winding in metal strip technology, where the position of the conductors in the slots is predetermined. Let n be the number of layers in the slots of the stator of a radial or axial flow electric machine. l , the number of slots is denoted by Z, and the total number of basic conductors (single strips across the frame) is n l Instead, the number of basic conductors across a single-phase frame is equal to (n l ·Z) / m.

[0026] For example, if we imagine a wound stator ideally cut radially and unfolded on a plane, we can see every single position of each elementary conductor, i.e., n of the conductors. l All Z positions can be seen. Figure 6(a) shows the case where the number of slots is Z=24 and the number of layers is n l= 4 and the number of pole pairs p = 2 (magnetic pole pairs of an electric machine with opposite polarity). The position of the basic conductor associated with each phase can be identified by the letters U, V, and W, respectively. The marking following the letter instead identifies the direction of the current at a determined instant of time t, which can be represented by a normal vector on the sheet. After identifying the phases and the direction of the current belonging to the schematic cell, it is necessary to add information related to the cardinality of the basic conductors.

[0027] In general, in an electric machine, phases are grouped into magnetic poles, and each pole has a sphere with adjacent slots in a number at least equal to the number of phases. In Figures 6(b) and 7, the first basic conductor 255 (or half coil) of a schematic path (where "path" is the path of current flowing through the winding) of a phase (in this case, U phase) can be identified by a number N=1 placed after the path's identifying letter (specifically, in this case, path A), the second conductor (or half coil) is identified by a number N=2, ..., the last conductor (or half coil) of the schematic path belonging to a phase is identified by a number N=(n l ·Z) / (m·a) and is equal to the number of parallel paths per phase.

[0028] At this point, after defining the winding, it is necessary to identify the various weld points that can form the complete winding. Generally, the weld points are between "N" of the schematic conductor (or half coil) and its neighbor "N+1", where "N" is equal. Thus, a schematic hairpin can be identified with "N" of the conductor (or half coil) and its neighbor "N+1", where "N" is an odd number.

[0029] Furthermore, one can pay attention to a certain spatial periodicity of the positions occupied by the conductors of the schematic phase. In particular, it is possible to define one or more "standard modules" or "standard models", as shown in Figure 8 for two cases and in Figure 9 for a complete example of the second case of Figure 8. When the standard modules are repeated with a certain period, one obtains a cell that specifies the schematic phase. Different standard modules can be used for different phases (on different layers).

[0030] In order for the phase paths to be electrically balanced, the number of conductors (or half coils) in each path must be N = (n l ·Z) / (m·a), and it is advantageous for it to be uniformly distributed over all occupied positions.

[0031] FIG. 10 shows one of the two paths of phase U and the respective arrangement of conductors (or half coils) to ensure electrical balance therebetween. (Half coil A occupies half of each phase, and the other half is occupied by a second path, not shown for ease of reading, resulting in a two-path arrangement; yp is the hairpin pitch (between slots or unit volumes) expressed in terms of slot number.) Note in particular that conductors (half coils) 1 and 3 occupy the left portion of the "standard module" of the first layer (the distal layer), and conductors 14 and 16 occupy the right portion of the "standard module" of the first layer. This results in the correct arrangement of conductors for the schematic path of the phase in the first layer. The same considerations can be made for the remaining layers.

[0032] In this prior art arrangement, conductors 8 and 9 located on the same layer are connected to each other by special connectors (jumpers, see above), which allow the series connection of half coils 1 to 8 located on the left part of the "standard module" with half coils 9 to 16 located on the right part of the "standard module". Note also that the jumpers for the paths shown in FIG. 10 of the schematic phase (phase U in this case) have a pitch of 5 slots; a second path, not shown, can occupy the remaining cells associated with the same phase (phase U in this particular case, identified by the cells with a dotted background) and may have a jumper pitch of 7 (5) slots if starting conductor 1 is on the first layer (4).

[0033] This allows the two parallel paths to be electrically balanced by the uniform distribution of conductors in each path on each layer. However, in industrial processes, the presence of these special components (jumpers) complicates the entire process from molding to resin processing of the product. Therefore, it is desirable to implement a winding pattern that does not use them, or uses them only in some specific cases, without compromising the electrical balance.

[0034] An example of a jumper-free winding pattern is disclosed in U.S. Pat. No. 1,074,9399 (Riedl et al.). A common feature of such prior art is the presence of single-layer hairpins. Indeed, hairpins are generally shaped so that their legs are located on two different layers of the winding, adjacent to each other. On the other hand, single-layer hairpins (or "inverted hairpins") are formed so that their legs are located on the same layer. Single-layer hairpins are typically used on the innermost (proximal) and outermost (distal) layers of the winding. Furthermore, in the aforementioned patent, these innermost and outermost hairpins have a specific relationship to each other in terms of hairpin pitch, i.e., the innermost one (toward the winding axis) is shorter or longer by one slot pitch. It should be noted that the patent explicitly excludes the presence of jumpers in most, but not all, cases (note the illustrated arrangement pattern, where the cardinality is greater in the inner layers (below the table)).

[0035] However, this particular design choice does not provide adequate flexibility, as defined above, because the number of possible parallel paths is limited if it is desired not to compromise electrical balance. For example, in the aforementioned patent, the pitch of the hairpins of one of the two single layers (inner or outer) is preferably equal to the pitch of the larger of the standard winding hairpins (the one belonging to the central crown of the stator winding). Furthermore, in the aforementioned patent, even in the presence of nested single-layer hairpins, it is impossible to reach the maximum number of parallel paths without compromising the electrical balance between the paths themselves. In the aforementioned patent, even in the presence of "twisted hairpins," which are often useful for windings, it is impossible to reach the maximum number of parallel paths without compromising the electrical balance between the paths themselves. Furthermore, the twist pitch of each layer (which can be defined as "the angle brushed (in terms of angle or slot pitch) by the conductor during the twisting stage to reach the conductor that must be welded to create the winding") is presumably fixed, since other conductor placement techniques, not mentioned at all, should be applied. With these stated constraints, it is not possible to achieve the maximum number of balanced parallel paths for a given combination of slot number, layer number, and pole pair number. In fact, the maximum number of parallel paths requires only one single-layer hairpin per end layer in a path, which means that at least one of the two single-layer hairpins must have its legs in the same part (right or left) of the "standard module" in prior art windings. This condition violates the electrical balance criterion mentioned above.

[0036] FIG. 11 shows an example of a winding pattern made according to the teachings of U.S. Pat. No. 1,074,9399 (Riedl et al.), with number of slots Z=24, number of phases m=3, number of pole pairs p=2, and number of parallel paths a=4. In prior art FIG. 7, the standard hairpin has a pitch of 6 slots. Instead, the single-layer hairpin of FIG. 11 has a pitch of 6 slots in the fourth (1) layer and 7 slots in the first (4) layer. Note that the aforementioned criteria are not respected (non-uniform distribution) by evaluating the spatial arrangement of the conductors belonging to the schematic paths of the phases of each single layer.

[0037] Figure 12 shows an example of a winding pattern from the same prior art, with slot number Z=24, phase number m=3, pole pair number p=2, and parallel paths a=4 (only one path is shown). Instead, the single-layer hairpin shown has a pitch of 6 slots in the fourth (1) layer and 5 slots in the first (4) layer. Note that the aforementioned criteria are not respected (uneven distribution of legs on the same position of a pair of phases) by evaluating the spatial arrangement of the conductors belonging to the phase path of each single layer.

[0038] Note that in the winding of FIG. 13 made by the same prior art: In the first layer (distal), conductors A7 and A8 occupy the left and right portions of the "standard module", respectively. On the second layer, both conductors A1 and A6 occupy the left portion of the "standard module". On the third layer, both conductors A2 and A5 occupy the left portion of the "standard module". In the fourth layer (proximal), both conductors A3 and A4 occupy the left portion of the "standard module." The resulting arrangement results in an imperfectly balanced winding pattern.

[0039] Figure 14 shows the case of a standard hairpin with a pitch of 5 slots, while the single-layer hairpin has a pitch of 6 slots in the fourth (1) layer and 5 slots in the first (4) layer. Note that the aforementioned criteria are not respected (non-uniform distribution) by evaluating the spatial arrangement of the conductors belonging to the schematic path of the phases of each single layer.

[0040] The same reasoning can be made for all four parallel paths shown in Figure 15. This arrangement results in an imperfectly balanced winding pattern.

[0041] Document DE102019218115A1 is also known, which describes a winding pattern using single-layer conductors, but they are not used in the distal and proximal layers, but only in the intermediate layer. More importantly, because they are used in only one intermediate layer, there is no difference in pitch between them (in the same winding pattern), as seen, for example, in arc conductors 570 and 670 (called "deflection conductors") in Figures 5 and 6. Instead, note that in Figure 4, arc conductors 451, 452, 453, and 454 all jump between layers. Therefore, document DE102019218115A1 cannot overcome the problems described above.

[0042] Furthermore, EP4138269A1 discloses a winding pattern using two types of hairpins with different pitches. These hairpins are alternately arranged along the circumferential direction of each layer and wired in a crosswise direction. Therefore, the multiple conductors forming each parallel circuit are uniformly distributed in each slit and each layer to form a balanced parallel circuit. Therefore, the balanced parallel circuit allows each parallel circuit to have the same magnetic interconnection flow, and currents can flow balanced along the multiple parallel circuits. However, this document does not address the balance when using a single-layer conductor, which is used to avoid the above-mentioned jumper conductor.

[0043] There is a need for innovations in the construction of multi-phase stator or rotor windings that can result in a wider group of windings and therefore an electrically balanced stator or rotor, preferably while maintaining the air gap diameter, slot count, and conductor dimensions. Summary of the Invention

[0044] It is an object of the present invention to provide a highly configurable stator or rotor winding, and a stator or rotor using such a winding, which completely or partially overcomes the problems and drawbacks of the prior art.

[0045] The present invention relates to a highly configurable stator or rotor winding and a stator or rotor using such a winding according to the appended claims. [Brief explanation of the drawings]

[0046] The present invention will now be described, by way of non-limiting example, with particular reference to the figures of the accompanying drawings, in which: [Figure 1] 1A and 1B show a preformed, flattened U-shaped hairpin (a) and a formed hairpin (b) according to the prior art. [Figure 2] Shown are the formed conductor (a) and the conductor after being twisted on the welded side (b). [Figure 3] FIG. 2(b) shows a top view of the hairpin of FIG. 2(a) according to the prior art. [Figure 4A] 1A and 1B show a prior art twisted hairpin with a cross section that reverses at the bend point (a) and a twisted hairpin that is continuously displaced along the portion of the hairpin that is housed in the slot (b). [Figure 4B] A twisted type hairpin is shown. [Figure 4C] In (a) to (c), three possible arrangements of the hairpin legs of a double crown winding at various positions in the slot are shown, with A and B indicating the crown to which the legs shown in the slot belong (belonging to different hairpins). [Figure 4D] 1 shows an example of a prior art "inverted hairpin." [Figure 4E] 1 shows an example of nested hairpins in different layers (a) and in the same layer (b) according to the prior art. [Figure 4F] 1 shows an example of the use of a jumper according to the prior art. [Figure 5] 1 shows an example of a single-layer hairpin according to the prior art. [Figure 6]In (a), a linear representation of the winding pattern of a 24-slot, 4-layer, 2-pole pair stator is shown. The position of the conductor associated with each phase can be identified by the letters U, V, and W, respectively (the phase is further indicated by the background of the cell, with U being a diagonal bar pointing to the left, W being no background, and V being a diagonal bar pointing to the right), while the mark following the letter identifies the direction of the current at a determined instant in time t, which can be represented by a normal vector on the sheet. In (b), a planar representation of a stator with only one coil, with legs or half coils in slots 1 and 7, respectively, according to an example of the prior art is shown (the phases are indicated using the same graphical convention as the cells in (a)). [Figure 7] 1 shows the structure of a path starting from a basic conductor half coil according to the prior art, with the slot array locations indicated by letters in (a) and a diagram of the half coil in (b) (phases are indicated using the same graphical convention as the cell in FIG. 6). [Figure 8] 7(a) and 9(b) show standard modules of the windings of FIG. 7 (phases using the same convention as in the previous figures), according to an example of the prior art. [Figure 9] The complete winding for the model (b) of Figure 8 is shown (same phase convention as in the previous figures). [Figure 10] This shows one of the two paths (A) of the U phase (using the same convention for phases as in the previous figures) and the respective arrangement of conductors (or half coils) that ensures electrical balance between them, in accordance with an example of the prior art. [Figure 11] This figure shows the arrangement of conductors for all four paths of a winding in a prior art example with slot number Z=24, pole pair number p=2, phase number m=3 (the same convention for phases as in the previous figure), and path number a=4. [Figure 12] This figure shows the arrangement of conductors in the phase paths for a winding according to the prior art, with the number of slots Z=24, the number of pole pairs p=2, the number of phases m=3 (the same convention for phases as in the previous figure), and the number of paths a=4. [Figure 13]This figure shows the arrangement of conductors for all four paths of a winding with slot number Z=24, pole pair number p=2, phase number m=3 (the same convention for phases as in the previous figures), and path number a=4, in accordance with an example of the prior art. [Figure 14] This shows an example of the prior art, in which the number of slots Z=24, the number of pole pairs p=2, the number of phases m=3 (the same convention for phases as in the previous figures), and the number of paths a=4 are arranged as conductors for the winding paths. [Figure 15] This figure shows the arrangement of conductors for all four paths of a winding with slot number Z=24, pole pair number p=2, phase number m=3 (the same convention for phases as in the previous figures), and path number a=4, in accordance with an example of the prior art. [Figure 16] 1 shows the arrangement of conductors of paths in a winding having the number of slots Z=24, the number of pole pairs p=2, the number of phases m=3 (the same convention for phases as in the previous figures), and the number of paths a=4, according to one embodiment of this specification. [Figure 17] 1 shows the layout of conductors for all four paths of a winding phase (other phases are filled in the same way) with slot number Z=24, pole pair number p=2, phase number m=3 (same convention for phases as in previous figures), and path number a=4, in accordance with one embodiment of the present specification. [Figure 18] 1 illustrates the conductor layout for a winding phase path (other phases are similarly filled) with slot count Z=72, phase count m=3 (same convention for phases as in previous figures), pole pair count p=6, and parallel path count a=12, according to one embodiment of the present specification; the approximate cells occupied by the paths are identified by a letter indicating the cardinality of the parallel path (in this case, A-N), followed by a number for the Nth conductor (or half coil). [Figure 19] 1 shows the layout of conductors for paths in a winding phase (other paths are similarly filled) with slot count Z=72, phase count m=3 (same convention for phases as in previous figures), pole pair count p=6, and parallel paths a=6, according to one embodiment of the present specification; the approximate cells occupied by the paths are identified by letters (in this case, A-F) using the same convention as in previous figures. [Figure 20]1 shows the layout of conductors for the paths of a phase (other paths are similarly filled) of a winding having number of slots Z=72, number of phases m=3 (same convention for phases as in previous figures), number of pole pairs p=6, and number of parallel paths a=4, according to one embodiment of this specification, with the approximate cells occupied by the phases identified by letters (in this case, A-D) using the same convention as in previous figures. [Figure 21] 1 shows the layout of conductors for the paths of phases (other paths are filled similarly) of a winding having Z=72 slots, m=3 phases (same convention for phases as in previous figures), p=6 pole pairs, and a=2 parallel paths, according to one embodiment of the present specification, with the approximate cells occupied by the phases identified by letters (in this case, A and B) using the same convention as in previous figures. [Figure 22] FIG. 1 shows the layout of conductors for the paths of a phase (other paths are similarly filled) of a winding using “twisted” hairpins with Z=72 slots, m=3 phases (same convention for phases as in previous figures), p=6 pole pairs, and a=6 parallel paths, according to one embodiment of the present specification. The approximate cells occupied by the phases are identified by the same letter convention as in previous figures (in this case, A-F), and twisted hairpins are used in layers 2 through 7. [Figure 23] An example winding pattern is shown with Z=36 slots, m=3 phases (using the same convention for phases as in previous figures), p=2 pole pairs, and a=4 parallel paths with four parallel paths. The approximate cells occupied by the phases are identified by the same letter convention as in previous figures (in this case, A-D). Two types of single layer hairpins (with pitches k and k+ / -3) are used in each end layer, and each phase has three slots per pole. [Figure 24] 24 shows an insertion side view and a perspective view of the winding according to the pattern of FIG. 23. DETAILED DESCRIPTION OF THE INVENTION

[0047] It should be noted here that, as those skilled in the art can easily understand from the above description, elements of different embodiments can be combined to provide further embodiments without limitation while respecting the technical concepts of the solutions in this specification.

[0048] Furthermore, this specification also refers to the prior art for the implementation of detailed features not described, such as minor elements that are commonly used in the prior art in solutions of the same type.

[0049] Whenever an element is introduced, it is understood that there can be "at least one" or "one or more."

[0050] Where a list of elements or features is recited herein, the teachings herein are understood to "comprise" or alternatively "consist of" such elements.

[0051] When features are listed in the same sentence or bulleted list, one or more of the individual features may be included herein without association with other features on the list.

[0052] Hereinafter, the terms "hairpin" and "elementary conductor" are used interchangeably for the conductors used herein.

[0053] This specification allows the elimination of the use of special connections (jumpers, etc.) in the stator or rotor windings without changing the shape of the hairpins that form the general path of the phases.

[0054] To illustrate this, note that a hairpin generally consists of two legs that are arranged in two different layers and are configured to be adjacent to each other when inserted into a slot according to its pitch. A single-layer hairpin instead consists of two legs that are configured to be arranged in a slot in the same layer. Figure 5 illustrates this situation, with a single-layer hairpin 260 inserted into slot 350 of stator 300 having shaft 210.

[0055] Next, according to this specification, special connections are eliminated by using specific single-layer hairpins in the innermost (proximal) and outermost (distal) layers. Another advantage of this specification is that the number of parallel paths, and therefore the number of half coils or conductors per path in one phase, N=(n l Flexibility is the ability to change (m·Z) / (m·a).

[0056] By using this specification, it is possible to obtain electrically balanced stator or rotor windings according to the above definition, in particular by utilizing single-layer hairpins with a specified pitch difference between the outer (distal) and inner (proximal) layers equal to at least 2. It should be noted that in almost all cases, according to this specification, no jumpers are used. In fact, the only cases in which jumpers are required according to this specification are in some specific winding configurations with only one path (e.g., two slots per pole per phase).

[0057] The example according to this specification is a winding with four parallel paths in FIG. 16, and the following can be noted. In the first layer (distal), conductors A7 and A8 occupy the left and right portions of the "standard module", respectively. On the second layer, conductors A1 and A6 occupy the left and right portions of the "standard module", respectively. On the third layer, conductors A2 and A5 occupy the left and right portions of the "standard module", respectively. In the fourth layer (proximal), conductors A3 and A4 occupy the left and right portions of the "standard module", respectively.

[0058] This means that the windings are electrically balanced, with single layer hairpins 261 used in the back layer (layer 1) having a pitch greater than two slots relative to single layer hairpins 262 in the top layer (layer 4). The same reasoning can be made for all four parallel paths shown in Figure 17, where a perfectly electrically balanced winding pattern also exists.

[0059] In this pattern, as in the other patterns shown in the figures, the phases are grouped into poles (U, V, W) with each pole having a number of adjacent slots in its sphere at least equal to the number of phases, although this is not necessary to respect the concepts herein.

[0060] According to another example embodiment of the present specification, shown in FIG. 18, an eight-layer winding pattern can have a number of slots Z=72, a number of phases m=3 (where the cell backgrounds are different for the various phases according to the same format as in the previous figures, and the same convention is used in subsequent FIGS. 19-23), a number of pole pairs p=6 (pairs of electric machine magnetic poles with opposite polarity), and a number of parallel (in-phase) paths a=12. In this exemplary embodiment, the pitch of the innermost single-layer hairpin 262 (first layer, distal) is 7, and the pitch of the outermost single-layer hairpin (black triangles outside the figure) 261 (eighth layer, proximal) is 5. In fact, the number of paths can be varied, for example, a=6, a=4, a=2, etc., as shown in FIGS. 19-21, without changing the shape of the hairpins or adding / changing special connections (e.g., jumpers), with the exception of the a=1 configuration, which requires one jumper per phase (connections A96-B1 in FIG. 21).

[0061] It should be noted that the prior art approach described in the aforementioned U.S. Pat. No. 1,0749,399, i.e., a single-layer hairpin with a one-slot pitch difference, does not allow for a configuration with a=12 parallel paths without compromising the electrical balance of the paths themselves. In fact, the technique described in such patent allows for balancing of windings with a maximum of six parallel paths. This specification does not recognize any predetermined limit to the number of paths that can be achieved.

[0062] For this reason, examples are provided in Figures 18-21 where the number of paths is different but the difference in slot pitch for single layer hairpins remains equal to 2 (7 and 5 for the first and last layer hairpins, respectively, going from top to bottom of the table).

[0063] Another example is provided in Figure 19, which shows the conductor layout for phase paths (other paths are similarly filled) for a winding phase with slot count Z = 72, phase count m = 3 (same graphical convention for phases as in previous figures), pole pair count p = 6, and parallel paths a = 6, with the approximate cells occupied by the paths identified with letters (in this case, A-F) using the same convention as in previous figures according to an embodiment of the present disclosure. Also in this case, there is perfect electrical balance across the six paths without the use of jumpers.

[0064] Another example is given in Figure 20, which shows the conductor layout for phase paths (other paths are similarly filled) of a winding with slot count Z=72, phase count m=3 (same graphical convention for phases as in the previous figures), pole pairs p=6, and parallel paths a=4, with the approximate cells occupied by the phases identified with the same letter convention (in this case, A-D) as in the previous figures according to an embodiment of the present disclosure. Also in this case, there is perfect electrical balance across the four paths without the use of jumpers.

[0065] A different example is shown in Figure 21, which shows the conductor layout for a phase path (other paths are similarly filled) of a winding with number of slots Z = 72, number of phases m = 3 (same graphical convention for phases as in the previous figures), number of pole pairs p = 6, and number of parallel paths a = 2, with the approximate cells occupied by the phases identified with the same letter convention (in this case, A and B) as in the previous figures according to an embodiment of this specification. Also in this case, there is perfect electrical balance between the two paths without the use of jumpers.

[0066] Yet another example is shown in FIG. 22, which shows the conductor layout of a winding phase path (other paths are similarly filled) using "twisted" hairpins with slot count Z=72, phase count m=3 (same graphical convention for phases as in previous figures), pole pair count p=6, and parallel paths a=6, with the approximate cells occupied by the phases identified by the same letter convention (in this case, A-F) as in previous figures according to one embodiment of the present disclosure, and with twisted hairpins used in layers 2 through 7. Also, in this case, with six paths, the pitch difference between the single-layer hairpins is equal to 2, and there is perfect electrical balance without the use of jumpers.

[0067] The final example is shown in Figure 23, which shows an example of a four-parallel path winding pattern with slot count Z=36, phase count m=3 (using the same phase convention as in the previous figures), pole pair count p=2, and parallel path count a=4. The approximate cells occupied by the phases are identified with the same letter convention (in this case, A-D) as in the previous figures, and two types of single-layer hairpins (with pitches k and k+ / -3) are used in each end layer. Also, in this case, the pitch difference between the single-layer hairpins is equal to 3 for the four paths, so there is perfect electrical balance between the paths without the use of jumpers. Note that in this case, the standard hairpins all have the same pitch (pitch 9 in this particular case), while the single-layer hairpins instead have pitches of 7 and 10 (k+ / -3) in the end layers, respectively. The single path configuration is achieved by making the A12-B1, B12-C1, and C12-D1 welds on the weld side of the winding. On the other hand, a configuration with two parallel paths can be obtained by welding A12-B1 and C12-D1.

[0068] As can be seen, in accordance with aspects of the present specification, it is generally possible to provide stator windings that use single layer hairpins whose pitch difference from other existing single layer hairpins is equal to a number of slots greater than one (counting from the next slot to the arriving slot), and the aforementioned "twisted hairpins" not present in the aforementioned patents are also used in the windings.

[0069] Figure 24 shows an insertion side view and a perspective view of winding 220 of drum or stator 230 having axis 210 according to the pattern of Figure 23, with the schematic phase hairpins having stylized graphical filling, particularly those for U phase designated by reference numeral 261, those for V phase designated by reference numeral 262, and those for W phase designated by reference numeral 263.

[0070] According to embodiments herein, it is possible to have several types of single layer hairpins in one or both end layers (distal and proximal), as seen, for example, in Figure 23 (note that there are two types of single layer hairpins in the end layer in terms of pitch) and Figure 24 (three types in terms of shape and two types in terms of pitch).

[0071] According to a different aspect of the present specification, in winding 220, at least one of the single-layer base conductors 261-263 located on the innermost (proximal layer) or outermost (distal layer) layer of the winding has two free ends (twist sides) that are angled in both circumferential directions (so as to prepare the winding for so-called "reverse twist", in which some wires of the crown are bent in the opposite direction to the standard twist direction in order to move some standard connections / welds).

[0072] The above is applicable to windings having at least one distal layer and at least one proximal layer, and advantageously also to windings having one or more intermediate layers, in particular at least two intermediate layers, between the distal and proximal layers.

[0073] Finally, the winding of the present invention may not include any jumpers.

[0074] The exemplary patterns shown above may be considered to describe the stator or rotor windings past the stator or rotor (e.g., after pre-assembly) or at the stator or rotor (after the windings have been transferred to the stator or rotor), regardless of whether all welding on the welding side has been performed. Twisted hairpins, I-pins, nested hairpins, and inverted hairpins can be used as single layer hairpins or standard hairpins as described above. advantage

[0075] In contrast to U.S. Pat. No. 1,074,939, one solution herein is to: In the aforementioned patent, the pitch difference between the inner / outer single layer hairpin and the outer / inner single layer hairpin is equal to 1, and in this specification, the pitch difference between the single hairpins is >1; In the aforementioned Riedl patent, the pitch of the hairpins of one of the two single layers (inner or outer, whichever is the widest) must be equal to the pitch of the standard winding hairpins (those belonging to the central crown of the stator winding), but this restriction is not contained in the present specification; The aforementioned patent does not allow for nested single layer hairpins, but the present specification instead allows for nested single layer hairpins within the stator windings; The aforementioned patent does not allow for "twisted hairpins", but this specification allows for the use of "twisted hairpins" in the windings; In the Riedl patent mentioned above, it is impossible to realize the maximum number of parallel paths while ensuring the electrical balance of the paths themselves (for example, in the patterns of Figures 8 and 9 of the publicly known patent, 16 parallel paths are impossible). It has the following innovative features.

[0076] Compared to US Pat. No. 1,074,9399, the present invention provides the following advantages: High flexibility thanks to a large number of parallel paths that can be achieved without compromising electrical balance. Simplification of the manufacturing process: in fact, it is possible to obtain a family of stators with the same diameter at the air gap, the number of slots and the dimensions of the conductors, with a different number of parallel paths, without compromising the electrical balance between the paths, and with a minimum impact on the manufacturing process.

[0077] In the solution herein, nested single layer hairpins can be used as the pitch varies by at least + / -2 (but without limitation 3, 4, 5, 6, etc.) relative to other layers below or above.

[0078] Although preferred embodiments have been described above and variations therein have been suggested, it will be understood that those skilled in the art can make modifications and changes without departing from the relevant scope of protection, as defined by the appended claims.

Claims

1. A multiphase bar stator or rotor winding (220) comprising two or more layers of elementary conductors, each of the elementary conductors having a head end connecting two legs, each leg having a corresponding free end, each layer consisting of a circumferential arrangement of elementary conductors (255, 255-S, 255-IP, 255-AC) wound about a central winding axis (210), a distal layer and a proximal layer being defined with respect to the winding axis, the legs of the elementary conductors being circumferentially adjacent in each layer in the winding and forming a radial series of volumetric units across a corresponding predetermined radial volumetric unit between layers, the angular distance with respect to the winding axis encompassed by each elementary conductor in the winding being measured in terms of the number of volumetric units between the two legs and referred to as the pitch, in the winding (220): all of the head ends (255c) of the basic conductors (255) are on a first side relative to the direction of the winding axis (210), and all of the free ends (255a, 255b) are on an opposite side to the first side; The basic conductors (255, 261, 262) are electrically connected from the opposite sides of the winding to form a plurality of single-phase paths, A plurality of single-layer basic conductors (261, 262) are included, and are configured such that two legs thereof are arranged in the same layer volume unit; At least one of the plurality of single phase paths has at least one distal single-layer basic conductor (262) located on the distal layer and having a first pitch (255p), and at least one respective proximal single-layer basic conductor (261) located on the proximal layer and having a second pitch (255p); The stator winding or rotor winding is the first pitch and the second pitch differ by two or more volume units; A multi-phase bar stator or rotor winding (220).

2. the first pitch and the second pitch differ by 2 volume units; The multiphase stator or rotor winding (220) of claim 1.

3. the first pitch and the second pitch differ by 3 volume units; The multiphase stator or rotor winding (220) of claim 1.

4. All of the paths of the plurality of paths have at least one distal single-layer elementary conductor (262) of a first pitch and at least one proximal single-layer elementary conductor (261) of a second pitch. A multiphase stator or rotor winding (220) according to any one of claims 1 to 3.

5. the plurality of base conductors (255, 261, 262) having nested base conductors; A polyphase stator or rotor winding (220) according to any one of claims 1 to 4.

6. the plurality of base conductors include twisted base conductors; A polyphase stator or rotor winding (220) according to any one of claims 1 to 5.

7. at least one of the distal single-layer basic conductors (262) and / or at least one of the proximal single-layer basic conductors (261) has two free ends angled in both circumferential directions, A winding (220) according to any one of claims 1 to 6.

8. At least one pitch of the basic conductors (255) other than the single-layer basic conductor corresponds to one of the first pitch and the second pitch. A winding according to any one of claims 1 to 7.

9. There is at least one intermediate layer between the distal layer and the proximal layer. A winding according to any one of claims 1 to 8.

10. There is no jumper, A winding according to any one of claims 1 to 9.

11. 11. A stator or rotor for an electric machine comprising a core having a series of slots and at least one conductor winding inserted into said slots, characterized in that said at least one conductor winding is at least one winding according to any one of claims 1 to 10.

12. An electric machine comprising a stator or rotor according to claim 11.

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