Stator or rotor winding with high configuration, and stator or rotor using such winding

Abstract

The present invention relates to a stator or rotor winding with high configuration, and to a stator or rotor using such a winding, in which single-layer hairpins with different pitches are used to distinguish at least two positions in slots. This arrangement allows a wider winding family to be obtained, thereby obtaining an electrically balanced stator or rotor, preferably maintaining the diameter at the air gaps, the number of slots and the size of the conductors.

Description

Technical Field

[0001] The present invention relates to a stator or rotor winding with high configurability, and a stator or rotor using such a winding. Background Art

[0002] It is well known to provide a stator or rotor for an electric machine (such as a generator or an electric motor) for applications, for example, on a hybrid electric vehicle (HEV), wherein the stator or rotor winding (single-phase or polyphase) consists of a plurality of bent strip conductors and is interconnected in different ways in order to obtain an electric winding also referred to as a "bar winding". Such a bent strip conductor is also referred to as a "hairpin-shaped conductor" or simply a "hairpin". The bar winding may consist of one or more sets of concentric windings, sometimes referred to as "crowns", each set of windings being a winding in itself ("packaged winding"). In turn, each crown may consist of one or more layers (see below), and thus the winding may consist of one or more bar layers. Each layer may include a series of complete bar conductors, or may also consist of bar conductor portions spanning two or more layers.

[0003] In particular, windings with hairpins having a circular cross-section (also referred to as "round wire conductors") or a rectangular cross-section are known in the prior art, or even conductors having a variable cross-sectional geometry along the length (for example, a circular conductor made rectangular in the portion accommodated in the slot). In this regard, in the present specification, a "rectangular" or "square" conductor refers to a wire having four substantially flat sides, each side being conventionally connected to an adjacent side by a rounded edge. Bar conductors having a trapezoidal cross-section are known.

[0004] The above-mentioned bar conductors are generally preformed by bending the bar conductor from a straight shape into a "U" shape or a "P" shape. Patent US 7,480,987 describes an example of a method for preforming a straight bar conductor to form a hairpin. The preformed conductor in the "U" shape or "P" shape is often also referred to as a "preformed basic conductor" in the technical field, and conventionally has two adjacent legs of equal or different lengths, each leg having a free end portion and an opposite end portion, and the opposite end portion is connected to the other of the two legs by a bridge-like connecting portion. Since the end portions protrude when inserted into the rotor or stator, they will be referred to as "free protruding portions" and "relatively connected protruding portions". The connected protruding portion may also be referred to as a "head portion" or a "bridge-like connecting portion". The assembly of the "head portions" of the legs of the same hairpin forms a so-called "bridge connection" or "bridge joint" or "hairpin head portion".

[0005] Referring to FIG. 1(a), the hairpin 255 is preformed from a linear hairpin (not shown) by bending it to form a first leg 255a having a respective free protruding end 255aE and a second leg 255b having a respective free protruding end 255bE. The bending simultaneously forms a bridge-shaped connector 255c between the two legs 255a, 255b. In this example, the preformed hairpin is in a flat "U" shape. For example, in order to form the stator of an electric machine, two different types of twisting are known for preformed hairpins in a "U" shape or a "P" shape.

[0006] The stator or rotor core of a radial flux electric machine is substantially a ring having two planes and two cylindrical surfaces, with a generator perpendicular to the two planes parallel to the axis of rotation of the electric machine rotor. Unless otherwise stated, the radial, circumferential, and axial directions hereinafter refer to the axes of the directions. At least 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 which defines a set of slots in which the straight portions of the windings are received. The two flat surfaces are divided into an insertion surface or side and a surface or side opposite the insertion side (welding side). The portions of the windings protruding from the core are called pins. The ends of the free portions of the conductors belong to the pins protruding from the side opposite the insertion side, most of which are welded. If there are protruding portions in the winding that are connected in a bridge-like manner to the legs inserted into the stator slots, they belong to the pins protruding from the insertion side. The portions protruding from the insertion side, whether free or connected in a bridge-like manner, are hereinafter referred to as the portions protruding from the insertion side.

[0007] The region of the stator or rotor core between one slot and an adjacent slot is called a tooth. The number of teeth is equal to the number of slots. The connecting portion of the core teeth is called a yoke, which defines a part of each slot and is located on the side opposite the slot opening in the machine air gap with respect to each slot.

[0008] The slots can be divided into position arrays in which the legs of the basic conductors can be placed. The conductors (or conductor portions) accommodated in the same radial position as the slots define the so-called winding layers. A series of slots closest to the axis of the (stator or rotor) array is generally called the "proximal layer", while a series of slots furthest from the axis of the (stator or rotor) array is generally called the "distal layer".

[0009] In a first type of twisting (also known as "twisting on the insertion side"), a preformed basic conductor is properly inserted into corresponding radially aligned grooves or "slots" provided in a twisting device, adapted to deform such a conductor after insertion. The twisting device is basically used to unfold the legs of a "U" - shaped or "P" - shaped configuration such that after the conductor is removed from the twisting device, the two legs of each conductor can then be inserted into corresponding pairs of slots in a stator core, the two legs being angularly offset from each other by a predetermined distance which is substantially equal to the angular distance between the slots, the legs being then inserted into the slots and being radially spaced apart by a certain radial distance between the slot positions respectively occupied by the legs.

[0010] For example, starting from a preformed hairpin, but not exclusively as shown in Fig. 1(a), a hairpin having a suitable shape for insertion into a stator (or rotor) is formed by widening the legs 255a, 255b and shaping the bridge - like connector 255c, for example to obtain the shape in Fig. 1(b). The reference numeral 255p denotes the pitch of the hairpin, i.e., the linear or angular distance between the legs, or the distance expressed in slot pitch or more generally "volume unit". It should be noted that in this case, the central top 255c2 of the shaped hairpin is the basic conductor, where the cross - section of the conductor undergoes a 180° rotation with respect to the middle surface of the hairpin (the ideal surface passing through the interior of the hairpin and including the two legs). This rotation is useful in some stranded hairpins, which will be defined below, for the purpose of permuting the layers (exchanging slot positions), and thus, compared to the case where the layers are run in parallel with the same layer and do not exchange slot positions during the transition from one leg to the other, reducing the eddy currents circulating through the ends of the layers when the layers are welded together.

[0011] The patent application with publication number US2009 / 0178270 describes an example of a method of twisting on the insertion side for twisting a preformed bar pin with a uniform pitch after inserting the preformed bar pin into a groove of a twisting device, where the hairpin has a rectangular cross - section.

[0012] According to the prior art and referring to Fig. 2, hairpins can also be obtained by molding, in which a straight conductor is pressed against a counter - part using a punch - and - die - type system. Fig. 2(a) shows such a molded conductor; the cross - section of this molded conductor does not rotate with respect to the middle surface of the hairpin.

[0013] As described above, the obtained molded hairpin or the preformed and deployed hairpin can withstand the so-called "welding side torsion", in which case, a "stepped" shape of the protruding portions of the legs 255a and 255b can be introduced, where, for example, the leg 255a has a first straight portion 255a1, a stepped portion 255a2, and a second straight portion 255a3 (substantially corresponding to the portion 255aE in FIG. 1), as shown in FIG. 2(b).

[0014] Referring to FIG. 3, the shape of the protruding portion (i.e., the bridge-like connector 255c) on the insertion side of the molded hairpin can include three portions 255c1, 255c3, and 255c2, which start from the connection with the second leg 255b and end at the connection with the first leg 255a (not visible in FIG. 3). The portion 255c1 has a main extension direction B and a radius of curvature R B and the portion 255c3 has a main extension direction A and a radius of curvature R A and the portion 255c2 has a main extension direction C (possibly with its curvature, not shown). Thereafter, the portion 255c2 is referred to as a "layer change bend"; in fact, by virtue of this, when the head and leg portions of the hairpin are inserted into the corresponding slots of the stator group, they are on different layers. The reference numeral α1 represents the angle between the direction A and the direction C, the reference numeral α2 represents the angle between the direction A and the direction B, and the reference numeral α3 represents the angle between the direction B and the direction C, which is equal to the sum of the angle α1 and the angle α2. This is just one of the possible final shapes of the hairpin, and all other shapes with different portions and the shapes of the bridge-like portion and the legs can be used with the devices and methods according to this specification.

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

[0016] In addition, referring to FIG. 4A, there is a stranded hairpin with a cross-sectional inversion at the bending point (FIG. 4A(a)), which causes an exchange of positions occupied by the layers. As noted from the type of hatching of the cross-section in FIG. 4A(a), due to this inversion or position exchange, the upper layer in the pair of layers in the left slot lies below the other layer in the right slot. In another form of hairpin, the transposition can be continuous along the part of the hairpin accommodated in the slot (FIG. 4A(b); Patent US 3837072). The variant shown in FIG. 4B is a stranded hairpin without inversion as shown in Patent US8552611 B2. FIG. 4C (obtained from FIG. 6 of Patent US 6,894,417 B2) provides a variant of the leg arrangement of the stranded hairpin 255-S in a double-crown winding at different slot positions. The reference letters A and B denote the crowns to which the legs belong, which are shown in the slots (belonging to different hairpins).

[0017] Referring to FIG. 4D (obtained from US10749399B2), the so-called "inverted hairpin" 255-IP, i.e., the hairpin can also be formed by spreading the legs (without using the above-mentioned insertion-side twisting method) or molded with a "stamping and die" system, is characterized in that the legs in the corresponding slots occupy the same radial position (generally referred to as a "single-layer hairpin"), i.e., they belong to the same layer. Thus, generally (except in the case of reverse twisting in the inner and outer crowns), the ends of the single-layer hairpin on the twisting side will bend in the same direction. In fact, the parts protruding on the side of the bridge-shaped connector can bend in the same tangential direction, or they can be in a V-shaped configuration. At least two-layer varying bends may be required on the connector part.

[0018] Finally, there are pairs of hairpins 255-AC, the corresponding legs of which belong to different layers (FIG. 4E(a)) or to the same layer (FIG. 4E(b)), and the pairs of hairpins are configured and dimensioned for nesting (regardless of the difference in pitch (or "volume unit") between the nesting elements). Each of the nested conductors is smaller than the other, so one is inside the other. Therefore, the most appropriate English term is considered to be "nested hairpins"; in any case, its configuration is obvious from the drawings.

[0019] Hereinafter, all of the above hairpin types, as well as any other hairpins having any number of legs and also being joined, will be included in the term "basic conductor".

[0020] After undergoing the first type of twisting or after molding, the basic conductors are conventionally pre-assembled in the complete winding as described above. The pre-assembly device will have a set of slots, which generally equals the number of slots of the stator associated with the winding, and the legs of each hairpin are inserted into the slots, and the device is generally different from the twisting device.

[0021] Subsequently, the complete set of windings is inserted as a whole into the slots of the stator core through its first side (the so-called "insertion side" or "insertion face"), and the corresponding free parts protrude from the second side of the core opposite the first side (the so-called "welding side" or "connection side" or "welding face" or "exit face"). Systems for transferring windings and inserting them into the stator assembly are also known.

[0022] Based on the specific winding pattern to be obtained, the free parts of the basic conductors protruding from the side opposite the insertion side can then be subjected to a second type of twisting, also known as "twisting on the welding side", for example after having been inserted into grooves made in a suitable twisting device. Here, the purpose of the twisting device is to bend or twist the free parts of the conductors in order to properly shape these free parts, thus allowing a proper electrical connection to be obtained between the conductors to complete the winding. Patent application US2009 / 0302705 describes an example of the above type of twisting method on the welding side.

[0023] The prior art provides different types of windings. However, windings often use special connections, such as "jumpers" and / or devices that make the windings very different from each other. An example of a jumper is provided in Figure 4F, where different conductors 255 located at least partially on the same layer are connected to each other by a jumper 270, which should be understood as a special connection. Jumpers usually consist of various types of connections to be welded. In other words, certain types of windings involve significant changes in the production equipment.

[0024] Therefore, there is a need for a polyphase winding pattern that can simply vary the number of parallel paths without modifying the components forming the winding (usually hairpins) and without adding any special connections. This flexibility should occur without compromising the correct arrangement of the basic conductors in the stator slots and thus without compromising the electrical balance of the various parallel paths.

[0025] To illustrate this situation of electrical balance, here is an example of a winding using the metal strip technique. In this case, the position of the conductors in the slots is predetermined. Let n l represent the number of layers in the stator slots of the motor with radial or axial flow, and Z represent the number of slots. The total number of basic conductors (single strips passing through the frame) will be equal to n l ·Z. On the contrary, the number of basic conductors passing through the frame in the case of a single phase is equal to Let m represent the number of phases.

[0026] For example, imagine that in an ideal situation, the wound stator is cut along the radial direction and unfolded in a plane, and the individual position of each basic conductor can be seen, and thus all n of the conductors can be seen l·Z position. Figure 6(a) shows an example with the number of slots Z = 24, the number of layers n l = 4 and the number of pole pairs p = 2 (paired motor magnetic poles with opposite polarities). The positions of the basic conductors associated with each phase can be represented by the letters U, V, and W respectively. Conversely, the marks behind the letters indicate the direction of the current at a determined moment in time t, and can be represented by the normal vectors in the table. After representing the phase and the direction of the current to which the general unit belongs, it is necessary to add information related to the basic conductor base number.

[0027] Generally, in an electric machine, the phases are grouped into magnetic poles, and within the range of each magnetic pole, a number of adjacent slots are provided, the number of slots being at least equal to the number of phases respectively. In Figures 6(b) and 7, it can be seen that the first basic conductor 255 (or half-coil) of the general path of a phase (in this case the U phase), where "path" is the path of the current in the winding, can be represented by the number N = 1, which is located after the identification letter of the path (in this specific case path A); the second conductor (or half-coil) will be represented by the number N = 2,... The last conductor (or half-coil) belonging to the general path of the phase will be represented by the number where a then equals the number of parallel paths of each phase.

[0028] At this time, after defining the winding, it is necessary to distinguish the various welding points that allow the formation of a complete winding. Generally, the welding points are between the general conductor (or half-coil) "N" and the next general conductor "N + 1", where "N" is equal. Thus, a general hairpin can be represented by the conductor (or half-coil) "N" and the next conductor "N + 1", where "N" is odd.

[0029] Furthermore, a certain spatial periodicity of the positions occupied by the conductors in the general phase can be noted. Specifically, one or more "standard modules" or "standard models" can be defined, as shown in two cases in Figure 8, and as described in the complete example for the second case in Figure 8 in Figure 9. When the standard module repeats with a certain period, it allows the obtaining of units that identify the general phase. Different standard modules can be used for different phases (on different layers).

[0030] To electrically balance the path of the general phase, it is advantageous for the N conductors (or half-coils) of each path to be evenly distributed among all the positions to be occupied, where

[0031] Figure 10 shows the arrangement of one of the two paths of phase U and the corresponding conductors (or half - coils) in order to ensure the electrical balance between them (the arrangement of the two paths, since half - coil A occupies half of each phase and the other half is occupied by the second path, not shown for ease of reading; yp is the hairpin pitch (between slots or volume units), expressed according to the number of slots). It should be noted in particular that conductors 1 and 3 occupy the left part of the "standard module" in layer 1 (the far - side layer), while conductors 14 and 16 occupy the right part of the "standard module" in layer 1. Thus, the correct arrangement of the conductors of the general path of the phase in layer 1 is obtained. The same consideration can be made for the remaining layers.

[0032] In this prior - art arrangement, conductors 8 and 9 located on the same layer are interconnected by a special connection (jumper, see above). This allows the series connection of half - coils 1 to 8 located on the left part of the "standard module" and half - coils 9 to 16 located on the right part of the "standard module". It should also be noted that the pitch of the jumper with respect to the path shown in Figure 10 for the general phase (in this case phase U) is 5 slots; the second path (not shown in the figure) can occupy the remaining units associated with the same phase (in this particular case, phase U is represented by the units with a dotted background), and if the starting conductor 1 is in layer 1(4), it can include a jumper with a pitch of 7(5) slots.

[0033] Thus, due to the uniform distribution of the conductors of each path on each layer, the two parallel paths are electrically balanced. However, in the industrial process, the presence of these special components (jumpers) complicates the entire process from their formation to the resin treatment of the product. Therefore, it is desirable to implement a winding pattern that does not use these special components or uses them only in a limited way in a few specific cases without compromising the electrical balance.

[0034] An example of a winding pattern without jumpers can be found in patent US10749399 (Riedl et al.). In such prior art, a common feature is the presence of single - layer hairpins. In fact, the hairpins are generally shaped such that in the winding, the legs of the hairpins are positioned on two different layers and are adjacent to each other. On the other hand, single - layer hairpins (or "inverted hairpins") are shaped such that their legs are positioned in the same layer. Single - layer hairpins are typically used in the innermost (proximal) and outermost (distal) layers of the winding. In addition, in the aforementioned patent, these innermost and outermost hairpins have a specific relationship with each other in terms of the hairpin pitch, that is, the innermost hairpin (towards the winding axis) is shorter or longer by exactly one slot pitch. It should be noted that this patent mostly clearly eliminates the presence of jumpers, but not entirely (note that in the array pattern in the figure, the inner layers are those with larger cardinal numbers (at the bottom of the table)).

[0035] However, as described above, this particular design choice does not provide suitable flexibility because the achievable parallel paths are limited in number if one wishes not to compromise its electrical balance. For example, in the aforementioned patent, the pitch of the hairpins in one of the two single layers (inner or outer layer) is preferably equal to the larger pitch of the standard winding hairpins (the hairpins belonging to the central crown of the stator winding). Furthermore, in the aforementioned patent, it is not possible to reach the maximum number of parallel paths without compromising the electrical balance between the paths themselves, and this is also the case in the presence of nested single-layer hairpins. Similarly, in the aforementioned patent, it is not possible to reach the maximum number of parallel paths without compromising the electrical balance between the paths themselves, and this is the case in the presence of "stranded hairpins", which are useful in the winding in many cases. In addition, the twist pitch on each layer (which can be defined as "the angle at which the conductor (in the form of an angle or slot pitch) reaches the angle brushed by the conductor that must be welded to form the winding during the twisting phase") may be fixed because other conductor arrangement techniques that are not even mentioned should be adopted additionally. Under the constraints of these statements, for a given combination of slot number, number of layers, and number of pole pairs, it is not possible to reach the maximum number of balanced parallel paths. In fact, the state of the maximum number of parallel paths only requires a single-layer hairpin at each end layer of each path; this means that in the windings of the prior art, at least one of the two single-layer hairpins must have legs in the same part (right or left) of the "standard module". This situation violates the above electrical balance criteria.

[0036] Figure 11 shows an example of a winding pattern made according to the teachings of US10749399 (Riedl et al.), which includes a slot number Z = 24, a phase number m = 3, a number of pole pairs p = 2, and a number of parallel paths a = 4. The standard hairpin of Figure 7 of the prior art has a pitch of 6 slots. In contrast, the single-layer hairpins in Figure 11 have pitches of 6 slots and 7 slots for layer 4(1) and layer 1(4) respectively. By evaluating the spatial arrangement of the conductors of the general paths belonging to the phase on each single layer, it can be noted that the aforementioned standard is not complied with (non-uniform distribution).

[0037] Figure 12 shows an example of a winding pattern of the same prior art, which includes a slot number Z = 24, a phase number m = 3, a number of pole pairs p = 2, and a number of parallel paths a = 4 (only one path is shown). In contrast, the single-layer hairpins in the figure have pitches of 6 slots and 5 slots for layer 4(1) and layer 1(4) respectively. By evaluating the spatial arrangement of the conductors of the general paths belonging to the phase on each single layer, it can be noted that the aforementioned standard is not complied with (non-uniform distribution of the legs in the same position in the paired positions of the phase).

[0038] In the winding in Figure 13, which is also constructed according to the same prior art, note that:

[0039] In the (distal) layer 1, conductors A7 and A8 respectively occupy the left part and the right part of the "standard module";

[0040] In layer 2, both conductor A1 and conductor A6 occupy the left part of the "standard module";

[0041] In layer 3, both conductor A2 and conductor A5 occupy the left part of the "standard module"; and

[0042] In the (proximal) layer 4, both conductor A3 and conductor A4 occupy the left part of the "standard module". The obtained arrangement results in an incompletely balanced winding pattern.

[0043] Figure 14 shows the case of a pitch of a standard hairpin with 5 slots. On the other hand, the single-layer hairpin has pitches of 6 slots and 5 slots for layer 4(1) and layer 1(4) respectively. By evaluating the spatial arrangement of the conductors of the general path belonging to the phase on each single layer, it can be noted that the aforementioned standard is not adhered to (non-uniform distribution).

[0044] The same reasoning can be carried out for all four parallel paths shown in Figure 15. This arrangement results in an incompletely balanced winding pattern.

[0045] Document DE102019218115A1 is also known, which describes a winding pattern using single-layer conductors. However, they are not used for the distal layer and the proximal layer, but for the intermediate layer. More importantly, they are only used for one intermediate layer, so there is no difference in pitch between them (in the same winding pattern). For example, see the arc conductors 570, 670 (referred to as "deflection conductors") in Figures 5 and 6. On the contrary, note that in Figure 4, the arc conductors 451, 452, 453, and 454 all perform layer jumps. Therefore, document DE102019218115A1 cannot overcome the problems of the above situation.

[0046] Similarly, document EP4138269A1 is known, which provides a winding pattern of two hairpins with different pitches. Such hairpins are arranged alternately in the circumferential direction on each layer and are wired in a cross direction. Therefore, the multiple conductors forming each parallel circuit are evenly distributed in each slit and each layer to form a balanced parallel circuit. Due to the balanced parallel circuit, each parallel circuit is allowed to have the same magnetic interconnection flow and the current is allowed to flow along the multiple parallel circuits in a balanced manner. However, as shown above, such a document does not solve the balance problem in the case of using single-layer conductors, and the single-layer conductors are used to avoid jumper conductors.

[0047] Innovations are needed in the structure of polyphase stator or rotor windings, which allow for obtaining a wider family of windings, thereby obtaining an electrically balanced stator or rotor, preferably maintaining the diameter at the air gap, the number of slots, and the dimensions of the conductors. Summary of the Invention

[0048] The object of the present invention is to provide a stator or rotor winding with high configurability, as well as a stator or rotor using such a winding, which can fully or partially overcome the problems and disadvantages of the prior art.

[0049] The present invention relates to a stator or rotor winding with high configurability, as well as a stator or rotor using such a winding according to the appended claims. Brief Description of the Drawings

[0050] The present invention will now be described by way of non-limiting examples, with particular reference to the figures in the drawings, wherein:

[0051] Figure 1(a) shows a preformed flat U-shaped hairpin according to the prior art, and Figure 1(b) shows a formed hairpin;

[0052] Figure 2(a) shows a molded conductor, and Figure 2(b) shows the conductor after undergoing torsional welding on the side;

[0053] Figure 3 shows the hairpin at the top of Figure 2(a) according to the prior art;

[0054] Figure 4A(a) shows a stranded hairpin with a cross-section inversion at the bending point according to the prior art, and Figure 4A(b) shows a continuous transposition along the portion of the hairpin accommodated in the slot;

[0055] Figure 4B shows a hairpin of the stranded type;

[0056] Figures 4C(a)-4C(c) show three possible arrangements of the hairpin legs of a double-crown winding in different positions in the slot; A and B represent the crowns (belonging to different hairpins) to which the legs shown in the slot belong;

[0057] Figure 4D shows an example of an "inverted hairpin" according to the prior art;

[0058] Figure 4E(a) shows an example of hairpins nested on different layers according to the prior art, and Figure 4E(b) shows an example of hairpins nested on the same layer;

[0059] Figure 4F shows an example of using jumpers according to the prior art;

[0060] Figure 5 shows an example of a single-layer hairpin according to the prior art;

[0061] (a) of FIG. 6 shows a linear representation of the winding pattern of a stator having 24 slots, 4 layers, and 2 pole pairs. The positions of the conductors associated with each phase can be identified by the letters U, V, and W respectively (the phases are further represented by the background of the cells: a left-slanting line represents U, no background represents W, and a right-slanting line represents V), and the markings behind the letters indicate the direction of the current at a certain moment in time t and can be represented by the normal vectors in the table; and (b) of FIG. 6 shows a planar representation of a stator having only one coil according to an example of the prior art, which has legs or half-coils in slot 1 and slot 7 respectively (the phases are represented by the same graphical convention as the cells in (a) of FIG. 6);

[0062] FIG. 7 shows the construction of a path starting from a basic conductor half-coil according to the prior art, where (a) of FIG. 7 gives a textual indication of the positions of the slot array, and (b) of FIG. 7 is a diagram of the half-coil (the phases are represented by the same graphical convention as the cells in FIG. 6);

[0063] (a) of FIG. 8 shows a standard module of the winding in FIG. 7 according to an example of the prior art, and (b) of FIG. 8 shows a standard module of the winding in FIG. 9 (the same convention as the previous phase diagrams);

[0064] FIG. 9 shows a complete winding according to the model in (b) of FIG. 8 (the same convention as the previous phase diagrams);

[0065] FIG. 10 shows one of the two paths (A) of phase U according to an example of the prior art (the same convention as the previous phase diagrams) and the corresponding arrangement of the conductors (or half-coils) such that the electrical balance between them can be ensured;

[0066] FIG. 11 shows the arrangement of the conductors of all four paths of a phase for a winding according to an example of the prior art, which has the number of slots Z = 24, the number of pole pairs p = 2, the number of phases m = 3 (the same convention as the previous phase diagrams), and the number of paths a = 4;

[0067] FIG. 12 shows the arrangement of the conductors of the paths of a phase for a winding according to the prior art, which has the number of slots Z = 24, the number of pole pairs p = 2, the number of phases m = 3 (the same convention as the previous phase diagrams), and the number of paths a = 4;

[0068] FIG. 13 shows the arrangement of the conductors of all four paths of a winding according to an example of the prior art, which has the number of slots Z = 24, the number of pole pairs p = 2, the number of phases m = 3 (the same convention as the previous phase diagrams), and the number of paths a = 4;

[0069] FIG. 14 shows the arrangement of the conductors of the paths of a winding according to an example of the prior art, which has the number of slots Z = 24, the number of pole pairs p = 2, the number of phases m = 3 (the same convention as the previous phase diagrams), and the number of paths a = 4;

[0070] Figure 15 shows the arrangement of conductors of all four paths of a winding according to an example of the prior art, having the number of slots Z = 24, the number of pole pairs p = 2, the number of phases m = 3 (the same convention as the previous phase diagram), and the number of paths a = 4;

[0071] Figure 16 Shows the arrangement of conductors of the paths in a winding according to one aspect of the present specification, having the number of slots Z = 24, the number of pole pairs p = 2, the number of phases m = 3 (the same convention as the previous phase diagram), and the number of paths a = 4;

[0072] Figure 17 Shows the arrangement of conductors of all four paths of a phase of a winding (the other phases are filled similarly) according to one aspect of the present specification, having the number of slots Z = 24, the number of pole pairs p = 2, the number of phases m = 3 (the same convention as the previous phase diagram), and the number of paths a = 4;

[0073] Figure 18 Shows the arrangement of conductors of the paths of a phase of a winding (the other phases are filled similarly) according to one aspect of the present specification, having the number of slots Z = 72, the number of phases m = 3 (the same convention as the previous phase diagram), the number of pole pairs p = 6, and the number of parallel paths a = 12, where the general unit occupied by the paths is identified by a letter (in this case from A to N), followed by a number indicating the base number of the parallel path relative to the Nth conductor (or half - coil);

[0074] Figure 19 Shows the arrangement of conductors of the paths of a phase of a winding (the other paths are filled similarly) according to one aspect of the present invention, having the number of slots Z = 72, the number of phases m = 3 (the same convention as the previous phase diagram), the number of pole pairs p = 6, and the number of parallel paths a = 6, where the general unit occupied by the paths is identified by letters having the same convention as the previous figure (in this case from A to F);

[0075] Figure 20 Shows the arrangement of conductors of the paths of a phase of a winding (the other paths are filled similarly), having the number of slots Z = 72, the number of phases m = 3 (the same convention as the previous phase diagram), the number of pole pairs p = 6, and the number of parallel paths a = 4, where, according to one aspect of the present specification, the general unit occupied by the phase is identified by letters having the same convention as the previous figure (in this case from A to D);

[0076] Figure 21Shows the arrangement of conductors of the phase paths of the winding (other paths are filled in a similar manner), having the number of slots Z = 72, the number of phases m = 3 (the same convention as the previous phase diagram), the number of pole pairs p = 6, and the number of parallel paths a = 2, where, according to one aspect of the present specification, the general units occupied by the phases are identified by letters (in this case A and B) having the same convention as the previous figure;

[0077] Figure 22 Shows the arrangement of conductors of the phase paths of the winding using "stranded" hairpins (other paths are filled in a similar manner), having the number of slots Z = 72, the number of phases m = 3 (the same convention as the previous phase diagram), the number of pole pairs p = 6, and the number of parallel paths a = 6, where the general units occupied by the phases are identified by letters (in this case A - F) having the same convention as the previous figure, and where, according to one aspect of the present specification, the stranded hairpins are used from the 2nd layer to the 7th layer;

[0078] Figure 23 Shows an example of a winding pattern with 4 parallel paths, having the number of slots Z = 36, the number of phases m = 3 (the same convention as the previous phase diagram), the number of pole pairs p = 2, and the number of parallel paths a = 4, where the general units occupied by the phases are identified by letters (in this case A - D) having the same convention as the previous figure, and two types of single - layer hairpins (with pitches k and k + / - 3) are used for each end layer, and where each phase has three slots per pole; and

[0079] Figure 24 Shows the insertion side view and perspective view of the winding according to the pattern in Figure 23

[0080] It should be noted here that the elements of different embodiments can be combined together to provide further embodiments without limitation, while respecting the technical concept of the solution of this description, as will be readily understood by those skilled in the art from the above description.

[0081] In addition, this specification also refers to the prior art to implement the present invention. As for the detailed features, those not important elements commonly used in the same type of solutions in the prior art are not described herein.

[0082] When an element is introduced, it is generally understood that there can be "at least one" or "one or more".

[0083] When listing a series of elements or features in this specification, it should be understood that according to the findings of this specification, it "includes" these elements or optionally "consists of" these elements.

[0084] ​When listing features within the same sentence or bulleted list, one or more individual features may be included in the specification without being connected to other features in the list.

[0085] Hereinafter, for the conductors used in this specification, the terms "hairpin" and "basic conductor" will be used interchangeably. Detailed Description

[0086] Examples

[0087] It is obvious that this specification allows the elimination of the use of special connections (such as jumpers) in the stator or rotor windings without modifying the shape of the hairpins that form the general path of the phase.

[0088] To illustrate this, note that a hairpin generally consists of two legs that are configured to be positioned in two different layers and adjacent to each other when inserted into the slots according to their pitch. A single-layer hairpin, instead, consists of two legs that are configured to be positioned in the slots of the same layer. FIG. 5 shows the case of a single-layer hairpin 260 inserted into the slots 350 of a stator 300 having an axis 210.

[0089] Now, according to this specification, by means of the specific use of single-layer hairpins in the innermost (proximal) layer and the outermost (distal) layer, specific connections are eliminated. Another effect of this specification is the flexibility in the ability to change the number of parallel paths and thus to change the number of half-coils or conductors per phase without modifying the shape of the hairpins (except for the use of single-layer hairpins) and without any impact on the process. each path.

[0090] By using this specification, in particular by exploiting a single-layer hairpin structure having a determined pitch difference of at least equal to 2 between the outer (distal) layer and the inner (inner) layer, an electrically balanced stator or rotor winding as defined above can be obtained. Note that, according to this specification, jumpers are hardly ever used. In fact, according to this specification, the only case where jumpers are needed is in the case of a configuration with only one path in certain specific windings (e.g., when the number of slots per pole per phase is 2).

[0091] An example according to this specification is Figure 16 a winding having four parallel paths, in which it can be noted that:

[0092] in the (distal) layer 1, conductors A7 and A8 respectively occupy the left and right parts of the "standard module";

[0093] in layer 2, conductors A1 and A6 respectively occupy the left and right parts of the "standard module";

[0094] In layer 3, conductor A2 and conductor A5 respectively occupy the left part and the right part of the "standard module"; and

[0095] In (the distal) layer 4, conductor A3 and conductor A4 respectively occupy the left part and the right part of the "standard module".

[0096] This means that the winding is electrically balanced, where a single-layer hairpin 261 is used on the bottom layer (layer 1), and this single-layer hairpin has a pitch longer than two slots relative to the single-layer hairpin 262 of the topmost layer (layer 4). For Figure 17 the same reasoning can be made for all four parallel paths shown in, where there still exists a perfect electrically balanced winding pattern.

[0097] In this pattern, like other patterns shown in the drawings, the phases are grouped into magnetic poles (U, V, W), and within the scope of each magnetic pole, there are provided some adjacent slots, and the number of slots is at least equal to the number of phases respectively. However, this is not necessary for complying with the concept of this specification.

[0098] According to another example of this specification, as Figure 18 shown, a winding pattern with 8 layers is possible, which includes the number of slots Z = 72, the number of phases m = 3 (where, according to the same legend in the previous figures, the background of the unit is different for different phases; the same convention is used for subsequent Figures 19 - 23 ), the number of pole pairs p = 6 (paired motor magnetic poles with opposite polarities) and the number of parallel paths a = 12 (for the same phase). In this exemplary embodiment, the pitch of the innermost single-layer hairpin 262 (layer 1, distal) is 7, while the pitch of the outermost single-layer hairpin (the black triangle outside the table) 261 (layer 8, proximal) is 5. In fact, for the same general pattern, the number of paths can be different, taking the following values: for example, as in Figures 19 - 21 , a = 6, a = 4, a = 2, without changing the shape of the hairpins and without adding / modifying specific connections (such as jumpers), the only exception being the configuration with a = 1, where each phase requires 1 jumper ( Figure 21 the connection A96 - B1 in).

[0099] It should be noted that according to the prior art method described in the aforementioned patent US10749399, a configuration with the number of parallel paths a = 12 cannot be achieved, that is, the single-layer hairpins have a pitch difference of one slot, without compromising the electrical balance of the paths themselves. In fact, with the technology described in that patent, a winding with a maximum of 6 parallel paths can be balanced. This specification allows for no predetermined limit on the number of achievable paths.

[0100] For this purpose, in Figures 18 - 21Examples are provided in which the number of paths changes, but the slot difference in the pitch of the single-layer hairpins is made equal to 2 (starting from the top in the table, the hairpins in the first and last layers are 7 and 5 respectively).

[0101] Figure 19 Another example is given in which the arrangement of the conductors of the paths of one phase of the winding (the other paths are filled similarly) is shown, having the number of slots Z = 72, the number of phases m = 3 (the same graphical convention as the previous phase diagram), the number of pole pairs p = 6, and the number of parallel paths a = 6. Wherein, according to one aspect of the present specification, the general cells occupied by the paths are identified by letters (in this case from A to F) having the same convention as the previous figure. Also in this case, perfect electrical balance can be achieved with path 6 without using jumpers.

[0102] Figure 20 Another example is given in which the arrangement of the conductors of the paths of one phase of the winding (the other paths are filled similarly) is shown, having the number of slots Z = 72, the number of phases m = 3 (the same graphical convention as the previous phase diagram), the number of pole pairs p = 6, and the number of parallel paths a = 4. Wherein according to one aspect of the present specification, the general cells occupied by the phases are identified by letters (in this case from A to D) having the same convention as the previous figure. Also in this case, perfect electrical balance can be achieved with 4 paths without using jumpers.

[0103] Figure 21 The example in is different, which shows the arrangement of the conductors of the paths of the phases of the winding (the other paths are filled similarly), having the number of slots Z = 72, the number of phases m = 3 (the same graphical convention as the previous phases), the number of pole pairs p = 6, and the number of parallel paths a = 2. Wherein according to one aspect of the present specification, the general cells occupied by the phases are identified by letters (in this case A and B) having the same convention as the previous figure. Also in this case, perfect electrical balance can be achieved with path 2 without using jumpers.

[0104] Figure 22 Another different example in shows the arrangement of the conductors of the paths of the phases of the winding using "stranded" hairpins (the other paths are filled similarly), having the number of slots Z = 72, the number of phases m = 3 (the same graphical convention as the previous phases), the number of pole pairs p = 6, and the number of parallel paths a = 6. Wherein, according to one aspect of the present specification, the general cells occupied by the phases are identified by letters having the same convention as the previous figure (in this case A - F), wherein the stranded hairpins are used from the 2nd layer to the 7th layer. Also in this case, since there are 6 paths for the single-layer hairpins and the pitch difference is equal to 2, perfect electrical balance can be achieved without using jumpers.

[0105] Figure 23The middle is the last example, which shows an example of a winding pattern with 4 parallel paths, having the number of slots Z = 36, the number of phases m = 3 (the same convention as in the previous phases), the number of pole pairs p = 2, and the number of parallel paths a = 4. Here, the general cells occupied by the phases are identified by letters (in this case A - D) with the same convention as in the previous figures. For each end layer, two types of single - layer hairpins (with pitches k and k + / - 3) are used. Also in this case, since there are 4 paths for the single - layer hairpins and the pitch difference is equal to 3, perfect electrical balance can be achieved between the paths without using jumpers. Note that in this case, all the standard hairpins have the same pitch (pitch 9 in this specific case); for the two end layers, the pitches of the single - layer hairpins are 7 and 10 (k + / - 3) respectively. A single - path configuration is obtained by welding A12 - B1, B12 - C1, and C12 - D1 on the welding side of the winding. On the other hand, a configuration with two parallel paths is obtained by welding A12 - B1 and C12 - D1.

[0106] As described above, according to one aspect of the present specification, generally, a stator winding using single - layer hairpins can be provided, where the pitch difference between the single - layer hairpins and other existing single - layer hairpins is equal to the number of slots greater than 1 (counting from the next slot until and including the slot reached), and the aforementioned "stranded hairpins" that do not exist in the aforementioned patent are also used in this winding.

[0107] Figure 24 Shows an insertion side view and a perspective view of the winding 220 in a drum or stator 230 with axis 210 according to the Figure 23 pattern in, where the hairpins of the general phase have the graphical fill shown in the legend. In particular, those hairpins in the U - phase are also represented by reference numeral 261, those in the V - phase are represented by reference numeral 262, and those in the W - phase are represented by reference numeral 263.

[0108] According to one aspect of the present specification, several types of single - layer hairpins can be provided on one or two end layers (distal and proximal), for example, as Figure 23 (in the end layer, note that there are two types of single - layer hairpins in terms of pitch) and Figure 24 shown, where there are three different types of single - layer hairpins in terms of geometry and two different types of single - layer hairpins in terms of pitch.

[0109] According to different aspects of the present specification, in the winding 220, at least one of the single-layer basic conductors 261-263 located on the innermost (proximal) layer or the outermost (distal) layer of the winding has two angled free ends (twisted sides) in opposite circumferential directions to prepare a so-called "anti-twisted" winding, such that some of the wires of the crown are bent in a direction opposite to the standard twisting direction, thereby moving some of the standard connectors / welds.

[0110] The above applies to windings having at least one distal layer and at least one proximal layer, advantageously a winding further including one or more intermediate layers between the distal layer and the proximal layer, especially at least two intermediate layers.

[0111] Finally, the winding of the present invention cannot contain any jumpers.

[0112] The exemplary patterns shown above can be considered as a description of the stator or rotor winding outside the stator or rotor (e.g., after its pre-assembly) or the stator or rotor winding in the stator or rotor (after transferring the winding to the stator or rotor), regardless of whether all the welds on the welding side have been completed. As described above, stranded hairpins, I-shaped pins, nested hairpins, and reverse hairpins can be used as single-layer hairpins or standard hairpins.

[0113] Advantages

[0114] Compared with the patent US10749399, a solution of the present specification includes the following innovative features:

[0115] In the aforementioned patent, the pitch difference between the inner / outer single-layer hairpins and the outer / inner single-layer hairpins is equal to 1; in the present specification, the pitch difference between individual hairpins > 1;

[0116] In the aforementioned Riedl's patent, the pitch of the hairpins in one of the two single layers (the inner layer or the outer layer, the widest layer) must be equal to the pitch of the standard winding hairpins (the hairpins belonging to the central crown of the stator winding); this limitation does not exist in the present specification;

[0117] In the aforementioned patent, it is impossible to have nested single-layer hairpins; the present specification can include single-layer hairpins nested inside the stator winding;

[0118] In the aforementioned patent, it is impossible to have "stranded hairpins"; the present specification can include using "stranded hairpins" inside the winding; and

[0119] It is impossible to achieve the maximum number of parallel paths while ensuring the electrical balance between the paths themselves with the mentioned Riedl's patent (e.g., for the patterns in FIGS. 8 and 9 of the known patent, 16 parallel paths are impossible).

[0120] With respect to patent US10749399 again, the present specification offers the following advantages:

[0121] Greater flexibility, since a large number of parallel paths can be achieved without compromising their electrical balance; and

[0122] Simplification of the manufacturing process: In fact, it is possible to obtain a stator family that maintains the diameter at the air gap, the number of slots, and the dimensions of the conductors, with different numbers of parallel paths, without compromising the electrical balance between the paths, with a minimal impact on the production process.

[0123] In the solution according to the present specification, nested single-layer hairpins can be used because the pitch varies by at least + / -2 (but not limited to 3, 4, 5, 6, etc.) with respect to another layer below or above.

[0124] Preferred embodiments have been described above, and variations of the present specification have been proposed, but it should be understood that those skilled in the art can make modifications and variations without departing from the relevant protection scope defined by the appended claims.

Claims

1. A polyphase strip stator or rotor winding (220) comprising two or more layers of elementary conductors, said elementary conductors including a head end connecting two legs, each leg having a respective free end, each layer consisting of a circumferential arrangement of elementary conductors (255, 255-S, 255-IP, 255-AC) wound around a central winding axis (210), a distal layer and a proximal layer, said distal layer and proximal layer being defined relative to said winding axis, wherein, in said winding, said legs of said elementary conductors pass through predetermined circumferentially adjacent volume units in each layer, said volume units being radially corresponding between layers to form a series of radial volume units, the angular distance covered by each elementary conductor in said winding relative to said winding axis being measured according to the number of volume units between said two legs and being called the pitch, wherein, in said winding (220): the head ends (255c) of said elementary conductors (255) are all on a first side with respect to the direction of said winding axis (210), and the free ends (255a, 255b) are all on the side opposite to said first side; said elementary conductors (255, 261, 262) in said winding are electrically connected from said opposite sides to form a plurality of single-phase paths; a plurality of single-layer elementary conductors (261, 262) are included and configured such that said two legs thereof are positioned in volume units of the same layer; and at least one path of said plurality of single-phase paths includes at least one distal single-layer elementary conductor (262) positioned in said distal layer and having a first pitch (255p), and at least one corresponding proximal single-layer elementary conductor (261) positioned in the proximal layer and having a second pitch (255p); the stator or rotor winding is characterized in that: said first pitch and said second pitch differ by two or more volume units.

2. The polyphase stator or rotor winding (220) according to claim 1, wherein, said first pitch and said second pitch differ by two volume units.

3. The polyphase stator or rotor winding (220) according to claim 1, wherein, said first pitch and said second pitch differ by three volume units.

4. The polyphase stator or rotor winding (220) according to any one of claims 1 to 3, wherein, all paths of said plurality of paths include at least one distal single-layer elementary conductor (262) having a first pitch and at least one proximal single-layer elementary conductor (261) having a second pitch.

5. The polyphase stator or rotor winding (220) according to any one of claims 1 to 4, wherein, said plurality of elementary conductors (255, 261, 262) include nested elementary conductors.

6. The polyphase stator or rotor winding (220) according to any one of claims 1 to 5, wherein, said plurality of elementary conductors include stranded elementary conductors.

7. The winding (220) according to any one of claims 1 to 6, characterized in that, 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 the two free ends angled in opposite circumferential directions.

8. The winding according to any one of claims 1 to 7, wherein, at least one basic conductor (255) other than the single-layer basic conductor has a pitch corresponding to one of the first pitch and the second pitch.

9. The winding according to any one of claims 1 to 8, wherein, there is at least one intermediate layer between the distal layer and the proximal layer.

10. The winding according to any one of claims 1 to 9, wherein, it does not have jumpers.

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

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

Images