Balanced winding layouts for electric motors

A winding arrangement for a stator of an electric motor includes winding hairpins arranged to form one or more phases. The stator includes a plurality of motor teeth forming a plurality of slots each configured to accommodate multiple layers. A first set of winding hairpins spanning of M slots are coupled in series and coupled to a phase lead, and are arranged sequentially in a first azimuthal direction. A jumper is arranged in a layer and is coupled in series with the first set of winding hairpins. A second set of winding hairpins configured to span of M slots are coupled in series between the jumper and a neutral lead. The second set of winding hairpins are arranged sequentially in the opposite azimuthal direction, and along with the first set of winding hairpins and the jumper, form a continuous electrical path between the phase lead and the neutral lead.

INTRODUCTION

The present disclosure is directed to balanced winding layouts for electric motors, and more particularly, to winding layouts having hairpins of a particular span with a reduced number of part variances.

SUMMARY

In some embodiments, the present disclosure is directed to a stator of an electric motor. The stator includes a plurality of motor teeth, a phase lead, a neutral lead, winding hairpins, and a same-layer jumper. The plurality of motor teeth form a plurality of slots configured to accommodate N layers, wherein N is an integer. The phase lead and the neutral lead are arranged in in a first layer of the N layers. A first set of winding hairpins, each configured to achieve a span of M slots, are coupled in series together and also coupled to the phase lead. The first set of winding hairpins are arranged sequentially in a first azimuthal direction. The jumper is arranged between slots of a second layer, and is coupled in series with the first set of winding hairpins. The second set of winding hairpins are each configured to achieve the span of M slots, and are coupled in series between the jumper and the neutral lead. The second set of winding hairpins are arranged sequentially in a second azimuthal direction opposite to the first azimuthal direction. The first set of winding hairpins, the jumper, and the second set of winding hairpins form a continuous electrical path between the phase lead and the neutral lead. In some embodiments, the first layer is a radially outermost layer, and the second layer is a radially innermost layer. In some embodiments, the first layer is a radially innermost layer, and the second layer is a radially outermost layer.

In some embodiments, the jumper is configured to achieve the span of M slots. In some embodiments, the jumper is configured to achieve a shorter span less than the span of M slots. In some embodiments, M is equal to seven slots such that seven stator teeth are arranged between legs of each of the first set of winding hairpins and between legs of each of the second set of winding hairpins. To illustrate, the side of the stator where the hairpins are laid out is referred to as the crown end while the other end of the stator where the hairpins are welded to form a continuous circuit for current flow is referred to as the weld end. In some embodiments, the pitch of the winding on the crown side is seven, while the pitch on the weld side is five. In some embodiments, a pitch of five in the crown side and a pitch of seven on the weld side is used. In some embodiments, an equal pitch is implemented on both the crown side and the weld side (e.g., a pitch of six on either side).

In some embodiments, the plurality of slots include 48 slots and the phase lead, the neutral lead, the first set of winding hairpins, the jumper, and the second set of winding hairpins correspond to a first winding of a first phase. In some such embodiments, the stator includes further windings corresponding to two additional phases.

In some embodiments, the present disclosure is directed to a stator having a plurality of slots and a plurality of phases arranged in the slots. Each phase includes a first set of winding hairpins coupled in series and arranged sequentially in a first azimuthal direction, a second set of winding hairpins coupled in series and arranged sequentially in a second azimuthal direction opposite the first azimuthal direction, and a jumper. Each of the first set of winding hairpins and each of the second set of winding hairpins include a span of M slots. The jumper is arranged in a single layer and is coupled in series with the first set of winding hairpins and with the second set of winding hairpins.

In some embodiments, the first set of winding hairpins, the second set of winding hairpins and the jumper correspond to a first continuous winding, and each phase includes a second continuous winding coupled in parallel with the first continuous winding. In some such embodiments, each second continuous winding includes a third set of winding hairpins coupled in series and arranged sequentially in the first azimuthal direction, a fourth set of winding hairpins coupled in series and arranged sequentially in the second azimuthal direction, and another jumper. Each of the third set of winding hairpins and each of the fourth set of winding hairpins include a span of M slots. The other jumper arranged in a single layer and is coupled in series with the third set of winding hairpins and with the fourth set of winding hairpins.

In some embodiments, the jumper is configured to achieve the span of M slots, and the additional jumper is configured to achieve a shorter span of less than M slots. In some embodiments, M is equal to seven slots such that seven stator teeth are arranged between legs of each first set of winding hairpins and between legs of each second set of winding hairpins. In some embodiments, the single layer is a radially outermost layer. In some embodiments, the single layer is a radially innermost layer.

In some embodiments, the plurality of phases includes three phases, wherein each phase of the three phases includes at least two windings coupled in parallel. The first set of winding hairpins, the second set of winding hairpins, and the jumper are included in a first winding of the at least two windings, for example.

In some embodiments, the present disclosure is directed to stator of an electric motor including a plurality of stator teeth, a plurality of winding hairpins, a plurality of jumper hairpins, and a jumper. The plurality of stator teeth form a plurality of slots, each configured to accommodate N layers, wherein N is an even integer. Each of the plurality of winding hairpins is configured to achieve a span, and includes N/2 subsets of winding hairpins, each subset of the N/2 subsets including a respective length corresponding to the span. Each of the plurality of jumper hairpins is configured to achieve the span. The plurality of jumper hairpins include N/2-1 subsets of jumper hairpins, and each subset of the N/2-1 subsets includes a respective length corresponding to the span. The jumper is arranged in a single layer of the N layers. The plurality of winding hairpins, the plurality of jumper hairpins, and the jumper are coupled in series to form a continuous electrical path of a phase.

In some embodiments, the single layer is a radially outermost layer. In some embodiments, the single layer is a radially innermost layer. In some embodiments, the jumper is configured to achieve the span. In some embodiments, the jumper is configured to achieve a short span less than the span.

In some embodiments, the plurality of winding hairpins, the plurality of jumper hairpins, and the jumper form a sequence, wherein the jumper is arranged at the center of the sequence, and wherein the jumper corresponds to a change in azimuthal winding direction of the plurality of winding hairpins and the plurality of jumper hairpins.

DETAILED DESCRIPTION

The present disclosure is directed to balanced winding layouts for electric motors. Electric vehicles, for example, may require motors exhibiting high torque and power for fast acceleration (e.g., especially for higher end vehicles). In a further example, as larger vehicles, such as Trucks and SUVs are electrified, the electric motors require increased torque and power. High power motors may require an increased number of windings connected in parallel (e.g., depending on the level of motor power). To illustrate, more parallel winding connections often require hairpins (e.g., in bar wound machines), resulting in multiple pitches per layer. Winding pitch (or “span”) refers to the number of slots one leg of hairpin is from the other leg of the hairpin. For example, a hairpin may extend a “full pitch,” which means the number of slots the hairpin covers is equal to number of slots divided by number of poles (e.g., typically an integer for integral slot machines). Conversely, the winding pitch can be “short” in which case the number of slots covered by the hairpin is less than the full pitch winding. Further, the winding pitch can be “long,” in which case the number of slots covered by the hairpin is greater than the full pitch. Many winding arrangements, when connecting windings in parallel, require hairpins in every layer to make several pitches: standard pitch (full pitch); short pitch; and (sometimes) long pitch.

The number of layers in a winding layout is defined by the number of conductors in each slot (e.g., stacked radially). In some arrangements, every conductor constitutes one layer. For example, a winding layout with 4 or 6 conductors per slot may have 4 or 6 layers of winding respectively. In some arrangements, parallel connections require a larger number of hairpin shapes (e.g., different pitches) in order to balance windings that are connected in parallel with each other. For example, several hairpin shapes may be required in order to balance these parallel windings such that the same phase (angle) is maintained with respect to each winding. To achieve the same angular phase, each winding should occupy the same location of the slot with respect to the winding pole an equal number of times. Achieving this can necessitate several shapes of hairpins for different layer pairs. As the number of required hairpin shapes increases, stator manufacturing can become more complicated (e.g., requiring more toolings with the associated tooling cost and longer cycle time), which can affect product cost and manufacturing time, and thus productivity. Balanced windings, as used herein, refer to the clockwise and counterclockwise oriented hairpin sequences used for each winding of a phase.

In some embodiments, the winding layouts of the present disclosure allow a balanced winding with a large number of coils connected in parallel and with a reduced numbers of hairpin shapes, thereby reducing the unit and production cost. Each pair of layers can include two sets of windings: a first set (referred to herein as a forward winding) is wound in the forward direction (e.g., azimuthal) around the stator to complete the winding and a second set (referred to herein as a reverse winding) is wound in the reverse direction (e.g., in the opposite azimuthal direction of the forward winding). In some arrangements, the forward winding and the reverse windings are balanced individually and are then connected in parallel (e.g., for increased power). However, this approach may require many hairpin shapes (e.g., hairpins having different spans), thus increasing the cost. In winding layouts of the present disclosure, the forward and reverse windings are not connected in parallel, but rather the forward and reverse windings are connected in series. For example, the forward and reverse windings of the present disclosure may either occupy all the slots in a layer or partially occupy the slots in every layer (e.g., depending on the number of parallel connections). As set forth in more detail with regards to the examples below, a forward winding can be connected (e.g., via a same-layer jumper) to a reverse winding, the forward and reverse windings complementing each other to make the winding fully balanced. The approach of the present disclosure utilizes standard shapes (e.g., full pitch hairpin) in layer pairs, thus reducing the number of different shapes in the winding layouts. For example, a same winding layout can apply to all of the forward winding, and after a same-layer jump, is connected to the reverse winding having a same or similar winding layout. The combination of the forward and the reverse windings can make the winding fully balanced, reducing the number of hairpin shapes.

An illustrative 10-layer stator is illustrated inFIGS.1-3, and an illustrative 6-layer stator is illustrated inFIGS.4-5. Several windings of each stator are illustrated in an isolated arrangement for purposes of clarity, and accordingly,FIGS.2-3and5may be considered partial assemblies.

FIG.1shows two perspective views (e.g., panels198and199) of an illustrative motor stator100with ten layers having balanced windings, in accordance with some embodiments of the present disclosure. The views shown in panels198and199are shown from different sides of the stator (e.g., rotated about 120 degrees relative to each other). Terminals111,112, and113are configured to be coupled to respective phases (e.g., A, B, and C) of the motor (e.g., three-phase, four-pole as illustrated). Stator body110includes a plurality of slots (e.g., 48 slots as illustrated, with slots1,4and6indicated, arranged between a plurality of stator teeth. A plurality of hairpins120are arranged in the slots (e.g., meeting each other at welds130). For example, as illustrated, hairpins120are configured to be inserted axially into slots, wherein each hairpin includes one or two legs which correspond to respective slots. For example, a hairpin of hairpins120may include two legs configured to fit into two respective slots (i) at a radial position (e.g., the two legs configured to fit in a first layer and second layer, respectively, forming a layer pair such as1-2,3-4,5-6,7-8,9-10), and (ii) across a predetermined pitch (e.g., number-of-slots width of the hairpin). Illustrative windings B1, B2, B3, and B4are shown in isolation for purposes of clarity inFIGS.2-3, and an illustrative wiring schematic of some phases of motor stator100is shown inFIGS.11A-11F(e.g., for four parallel windings B1, B2, B3, and B4). In some embodiments, hairpins120include standard hairpins (e.g., hairpins having a common shape) extending across a span and layer pair, and a same-layer winding jumper to connect forward windings with reverse direction windings. Accordingly, stator100may reduce the number of wire (e.g., hairpin) shapes, which may reduce tooling cost and improve production cycle time.

FIG.2shows two perspective views (e.g., panels298and299) of illustrative motor stator100ofFIG.1with only winding for two respective parallel windings installed (e.g., winding B1in panel298and winding B2in panel299), in accordance with some embodiments of the present disclosure. The views shown in panels298and299are shown from the same side of the stator. For example, panel298illustrates a winding281(e.g., winding B1), and panel299illustrates a winding282(e.g., winding B2), which is connected in parallel with the winding281shown in panel298.FIG.3shows two perspective views (e.g., panels398and399) of illustrative motor stator100ofFIG.1with only windings for two further respective parallel windings381and382installed (e.g., winding B3in panel398and winding B4in panel399) in accordance with some embodiments of the present disclosure. The views shown in panels398and399are shown from the same side of the stator (e.g., and rotated about 150 degrees from those shown inFIG.2). For example, panel398illustrates a winding381, and panel399illustrates a winding382connected in parallel with windings281and282. In the examples shown inFIG.2andFIG.3, windings281,282,381, and382(e.g., windings B1, B2, B3, and B4of phase B) are connected in parallel with each other to form the winding of phase B. As illustrated inFIG.2, slots1,13and20are indicated by lead lines in panel298, and slots1,14, and19are indicated by lead lines in panel299.

Referencing panel298showing winding281, winding lead291enters slot13(“slot13” of 48 slots) at layer10(i.e., the outermost layer) from the lead side (e.g., axially, at the top as illustrated), with the hairpins of winding281forming a continuous path to neutral lead292(e.g., at slot20, as illustrated). As illustrated in panel298ofFIG.2, the hairpins of winding281include:Layer10phase lead (hairpin291);Layer10neutral lead (hairpin292);Layer9-10regular hairpins (hairpins202and203);Layer7-8regular hairpins (hairpins206and207);Layer5-6regular hairpins (hairpins212and213);Layer3-4regular hairpins (hairpins216and217);Layer1-2regular hairpins (hairpins222and223);Layer8-9jumpers (hairpins204and205);Layer6-7jumpers (hairpins208and209);Layer4-5jumpers (hairpins215and214);Layer2-3jumpers (hairpins218and219); andLayer1-1jumper (hairpin224, having the same span as the other hairpins of phase B1).
The current path of phase B1follows, in sequential order, hairpins291(lead),202,204,206,208,212,214,216,218,222,224(e.g., where winding direction changes from counter-clockwise to clockwise),223,219,217,215,213,209,207,205,203, and292(neutral). As illustrated, each of the two-leg hairpins of winding B1have a span of 7.

Referencing panel299showing winding282, winding lead293enters slot14at layer10from the lead side (e.g., axially, at the top as illustrated), with the hairpins of winding282forming a continuous path to neutral lead294(e.g., at slot19, as illustrated). The hairpins of winding282include:Layer10phase lead (hairpin293);Layer10neutral lead (hairpin294);Layer9-10regular hairpins (hairpins232and233);Layer7-8regular hairpins (hairpins236and237);Layer5-6regular hairpins (hairpins242and243);Layer3-4regular hairpins (hairpins246and247);Layer1-2regular hairpins (hairpins252and253);Layer8-9jumpers (hairpins234and235);Layer6-7jumpers (hairpins238and239);Layer4-5jumpers (hairpins245and244);Layer2-3jumpers (hairpins248and249); andLayer1-1jumper (hairpin254, with a shorter span than the other hairpins of winding B2).
The current path of winding282follows, in sequential order, hairpins293(lead),232,234,236,238,242,244,246,248,252,254(e.g., where winding direction changes from counter-clockwise to clockwise),253,249,247,245,243,239,237,235,233, and294(neutral). All of the two-leg hairpins of phase B1have a span of 7, except hairpin254(e.g.,1-1jumper) with a span of 5, as illustrated.

Referencing panel398showing winding381(i.e., winding381), winding lead391enters slot13at layer1from the lead side (e.g., axially, at the top as illustrated), with the hairpins of winding381forming a continuous path to neutral lead392(e.g., at slot6, as illustrated). The hairpins of winding381include:Layer1phase lead (hairpin391);Layer1neutral lead (hairpin392);Layer9-10regular hairpins (hairpins322and323);Layer7-8regular hairpins (hairpins316and317);Layer5-6regular hairpins (hairpins312and313);Layer3-4regular hairpins (hairpins306and307);Layer1-2regular hairpins (hairpins302and303);Layer8-9jumpers (hairpins318and319);Layer6-7jumpers (hairpins314and315);Layer4-5jumpers (hairpins308and309);Layer2-3jumpers (hairpins304and305); andLayer10-10jumper (hairpin324, having the same span as the other hairpins of phase B3).
The current path of phase381follows, in sequential order, hairpins391(lead),302,304,306,308,312,314,316,318,322,324(e.g., where winding direction changes from clockwise to counter-clockwise),323,319,317,315,313,309,307,305,303, and392(neutral). All of the two-leg hairpins of winding381have a span of 7, as illustrated.

Referencing panel399showing winding B4(i.e., winding382), winding lead393enters slot12at layer1from the lead side (e.g., axially, at the top as illustrated), with the hairpins of winding382forming a continuous path to neutral lead394(e.g., at slot7, as illustrated). The hairpins of winding B4include:Layer1phase lead (hairpin393);Layer1neutral lead (hairpin394);Layer9-10regular hairpins (hairpins352and353);Layer7-8regular hairpins (hairpins346and347);Layer5-6regular hairpins (hairpins342and343);Layer3-4regular hairpins (hairpins336and337);Layer1-2regular hairpins (hairpins332and333);Layer8-9jumpers (hairpins348and349);Layer6-7jumpers (hairpins344and345);Layer4-5jumpers (hairpins338and339);Layer2-3jumpers (hairpins334and335); andLayer10-10jumper (hairpin354, with a shorter span than the other hairpins of winding B4).
The current path of winding382follows, in sequential order, hairpins393(lead),332,334,336,338,342,344,346,348,352,354(e.g., where winding direction changes from clockwise to counter-clockwise),353,349,347,345,343,339,337,335,333, and394(neutral). All of the two-leg hairpins of winding382have a span of 7, except hairpin354(e.g.,10-10jumper) with a span of 5, as illustrated.

Accordingly, for windings281,282,381, and382(i.e., windings B1-B4), it can be summarized that:first set of hairpins202,203,232,233,322,323,352, and353are the same;second set of hairpins206,207,236,237,316,317,346, and347are the same;third set of hairpins212,213,242,243,312,313,342, and343are the same;fourth set of hairpins216,217,246,247,306,307,336, and337are the same;fifth set of hairpins222,223,252,253,302,303,332, and333are the same;jumpers204,205,234,235,318,319,348, and349are the same;jumpers208,209,238,239,314,315,344, and345are the same;jumpers214,215,244,245,308,309,338, and339are the same;jumpers218,219,248,249,304,305,334, and335are the same;jumper224is unique;jumper254is unique;jumper324is unique;jumper354is unique;leads291and293are the same;leads292and294are the same;leads391and393are the same; andleads392and394are the same, as summarized in Table 1, below.

As shown in this example, two of the 4 parallel paths of windings of phase B (e.g., windings B1, B2, illustrated inFIG.2) start on the outside at layer10and wind clockwise until the inside is reached at layer1where the winding direction changes. The other two parallel paths of phase B (e.g., windings B3, B4illustrated inFIG.3) start on the inside at layer1and wind clockwise until the outside is reached at layer10where the winding direction changes.

FIG.4shows two perspective views (e.g., panels498and499) of illustrative motor stator400with six layers having balanced windings, in accordance with some embodiments of the present disclosure. The views shown in panels498and499are shown from opposite sides of the stator (e.g., rotated about 180 degrees relative to each other). Motor stator400, as illustrated, corresponds to a 3-phase, 8-pole motor, although it will be understood the arrangements of the present disclosure may be applied to any suitable electric motor having any suitable number of slots, poles, phases, and layers. Terminals411,412, and413are configured to be coupled to respective phases (e.g., A, B, and C) of the motor (e.g., three-phase, eight-pole as illustrated). Stator body410includes a plurality of slots (e.g., 48 slots as illustrated, with line421showing slot1, line431showing slot47, line441showing slot3, and line451showing slot6), arranged between a plurality of stator teeth. A plurality of hairpins420are arranged in the slots (e.g., meeting each other at welds430). For example, as illustrated, hairpins420are configured to be inserted axially into slots (e.g., and welded on the opposite axial side from insertion, as illustrated by welds430), wherein each hairpin includes one or two legs which correspond to respective slots. For example, a hairpin of hairpins420may include two legs configured to fit into two respective slots (i) at a radial position (e.g., the two legs configured to fit in a first layer and a second layer, respectively, forming a layer pair such as1-2,3-4,5-6), and (ii) across a predetermined pitch (e.g., number-of-slots width of the hairpin).

FIG.5shows two perspective views (e.g., panels598and599) of the illustrative motor stator ofFIG.4with only windings for two respective parallel windings per phase installed (e.g., winding B1in panel598and winding B2in panel599), in accordance with some embodiments of the present disclosure. Panel598illustrates winding581(e.g., winding B1of phase B), while panel599illustrates winding582(e.g., winding B2of phase B), wherein windings581and582are connected in parallel to form the winding of phase B. An illustrative wiring schematic of some phases of motor stator400is shown inFIG.12(e.g., for windings581and582). The views shown in panels598and599are shown from opposite sides of the stator (e.g., rotated about 180 degrees relative to each other). As illustrated inFIG.5, slots14and19are indicated by lead lines in panel598, and slots13and20are indicated by lead lines in panel599.

Referencing panel598showing winding581(i.e., winding B1), phase lead591enters slot14at layer6from the lead side (e.g., axially, at the top as illustrated). A first set of counter-clockwise hairpins502,503, and504, and jumper505extend counter-clockwise around in layers5and6, which continue to second set of counter-clockwise hairpins512,513, and514, and jumper515which extend counter-clockwise around in layers3and4, which continue to third set of counter-clockwise hairpins522,523,524, and jumper525which extend counter-clockwise around in layers1and2. While hairpins502-504,512-514, and522-524, and jumpers505and515have the same span (e.g., 7 slots, as illustrated), jumper525, as illustrated, includes a different span (e.g., 5 slots as illustrated). Jumper525is termed a “1-1” jumper because is extends between slots at layer1and marks the winding position where the azimuthal winding direction changes (e.g., counter-clockwise winding direction changes to clockwise for winding581). A third set of clockwise hairpins532,533, and534, and jumper535extend clockwise around in layers1and2, which continue to another second set of clockwise hairpins542,543, and544, and jumper545which extend clockwise around in layers3and4, which continue to another first set of clockwise hairpins552,553, and554which extend clockwise around in layers1and2, and continue to neutral lead592(e.g., at slot19, as illustrated). Hairpins532-534,542-544, and552-554, and jumpers535and545have the same span (e.g., 7 slots, as illustrated). Accordingly, hairpins502-504and552-554are the same, hairpins512-514and542-544are the same, and hairpins522-524and532-534are the same, with each set differing in length (e.g., all have the same span, but the azimuthal distance changes based on layer pairs as the radius changes).

Referencing panel599showing winding582(i.e., winding B2), phase lead593enters slot13at layer6from the lead side (e.g., axially, at the top as illustrated). A first set of hairpins506,507, and508, and jumper509extend counter-clockwise around in layers5and6, which continue to second set of hairpins516,517, and518, and jumper519which extend counter-clockwise around in layers3and4, which continue to third set of hairpins526,527,528, and jumper529which extend counter-clockwise around in layers1and2. Hairpins506-508,516-518, and526-528, and jumpers509,519and529have the same span (e.g., 7 slots, as illustrated). Jumper529is also a “1-1” jumper because is extends between slots at layer1, and marks the winding position where the direction changes (e.g., counter-clockwise to clockwise for winding582), but includes the same span as the hairpins. Another third set of hairpins536,537, and538, and jumper539extend clockwise around in layers1and2, which continue to another second set of hairpins546,547, and548, and jumper549which extend clockwise around in layers3and4, which continue to another first set of hairpins556,557, and558which extend clockwise around in layers1and2, and continue to neutral lead594(e.g., at slot20, as illustrated). Hairpins536-538,546-548, and556-558, and jumpers539and549have the same span (e.g., 7 slots, as illustrated). Accordingly, for windings581and582, it can be summarized that:first set of hairpins502-504,506-508,552-554, and556-558are the same;second set of hairpins512-514,516-518542-544, and546-548are the same; andthird set of hairpins522-524,526-528,532-534, and536-538are the same,with each set differing only in length (e.g., all have the same span but the azimuthal distance changes based on layer pairs as the radius changes).
The total number of different shapes of winding hairpins are illustrated in Table 2, below.

TABLE 2Tabulation of number of unique components required (6-layer).HairpinTypeNumberNotesRegular3(three sizes for radial position differences)Jumper2(layer 5-4 jump, layer 3-2 jump)Jumper2(5-slot 1-1 jump, 7-slot 1-1 jump)Phase1All 6 phase leads are the sameNeutral1All 6 neutral leads are the sameTotal9

FIG.6shows three end views (e.g., panels600,630, and650) of illustrative slot arrangements having different numbers of conductor layers, in accordance with some embodiments of the present disclosure. Panel600illustrates a six-conductor per slot arrangement. For reference, the azimuthal direction (e.g., the direction of slot indexing) and radial direction (e.g., direction of layer indexing) are indicated in panel600, and are oriented similarly in panels630and650. Panel630illustrates an eight-conductor per slot arrangement. Panel650illustrates a ten-conductor per slot arrangement. In each of panels600,630, and650, several windings are illustrated for three phases (e.g., with parts of phase A repeating, but with the opposite current flow orientation). As illustrated, each arrangement of panels600,630, and650includes slots601-606, and stator teeth611-615arranged between adjacent slots. In each of panels600,630, and650, several windings are illustrated for three phases (e.g., with parts of phase A repeating, but with the opposite current flow orientation). As illustrated in each of panels600,630, and650, the windings for each phase are distributed between three of the slots shown, where slot is shared with other phases for two of the three slots. As illustrated, windings of Phase A of a first polarity (e.g., current into or out of the page, as illustrated) are included in slots601and602, and windings of Phase A having an opposite polarity are included in slot606. As illustrated, windings of Phase B of a first polarity are included in slots602,603, and604. As illustrated, windings of Phase C of a first polarity are included in slots604,605, and606. Staggering of the windings between three slots among the layers (e.g., the radial staggering of Phase A windings between slots601,602, and606in panel600, and Phases B and C as well) can lower the fifth and the seventh order winding harmonics, resulting in lower torque ripple, which can be a source of motor noise. In some embodiments, not illustrated inFIG.6, the winding of each phase may be distributed in two slots where there will be no sharing of phases within each of these slots. To illustrate, the latter may be preferred for manufacturing reasons but at the expense of higher spatial harmonics in the motor in some circumstances.

FIG.7shows three end views (e.g., panels700,730, and750) of further illustrative slot arrangements having different numbers of conductor layers, in accordance with some embodiments of the present disclosure. To illustrate,FIGS.6and7provide illustrative arrangements of windings in slots, in accordance with some embodiments of the present disclosure. For reference, the azimuthal direction (e.g., the direction of slot indexing) and radial direction (e.g., direction of layer indexing) are indicated in panel700, and are oriented similarly in panels730and750. Panel700illustrates a six-conductor per slot arrangement. Panel730illustrates an eight-conductor per slot arrangement. Panel750illustrates a ten-conductor per slot arrangement. As illustrated, each arrangement of panels700,730, and750includes slots701-706, and stator teeth711-715arranged between adjacent slots. In each of panels700,730, and750, several windings are illustrated for three phases (e.g., with parts of phase A repeating, but with the opposite current flow orientation). As illustrated in each of panels700,730, and750, the windings for each phase are distributed between three slots where slot is shared with other phases for two of the three slots. As illustrated, windings of Phase A of a first polarity (e.g., current into or out of the page, as illustrated) are included in slots701and702, and windings of Phase A having an opposite polarity are included in slot706. As illustrated, windings of Phase B of a first polarity are included in slots702,703, and704. As illustrated, windings of Phase C of a first polarity are included in slots704,705, and706. Staggering of the windings between three slots among the layers (e.g., the radial staggering of Phase A windings between slots701,702, and706in panel700, and Phases B and C as well) can lower the fifth and the seventh order winding harmonics, resulting in lower torque ripple, which can be a source of motor noise. In some embodiments, the winding of each phase may be distributed in two slots where there will be no sharing of phases within a slot. To illustrate, the latter may be preferred for manufacturing reasons but at the expense of higher spatial harmonics in the motor in some circumstances.

FIGS.8A-8F,9A-9F,10A-10F,11A-11F, and12A-12Fshow illustrative wiring schematics for different sized slots and/or different winding pitches. The wiring schematics ofFIGS.8A-12Fare illustrated for forty-eight slot arrangements, with the slot numbers illustrated. The weld side is illustrated as the top side of each layer (see e.g., weld side820) and the lead side is illustrated as the bottom side of each layer (see e.g., lead side821).

FIGS.8A-8Fshow an illustrative wiring schematic corresponding to parallel windings of one phase (e.g., B phase) of an eight-layer stator, with a winding pitch of six slots, in accordance with some embodiments of the present disclosure.FIGS.8A-8Fare arranged in a 2×3 array to form a composite table, withFIGS.8A-8Carranged in a 1×3 array, from left to right to form one table, and withFIGS.8D-8Farranged underneath in a 1×3 array, from left to right to form another table. The winding schematic ofFIGS.8A-8Fis arranged with slots indexed along the horizontal axis and layers indexed along the vertical axis. The paths of windings B1, B2, B3, and B4are illustrated inFIGS.8A-8F(e.g., as windings801-804). As illustrated, hairpins can be inserted axially from the bottom of each layer (e.g., the crown side, or lead side821), with the leg(s) of the hairpin extending vertically in the corresponding slot(s). As illustrated, welds810between legs of hairpins are illustrated on the top (e.g., weld side820), represented by thick rectangular segments (an example weld point810is shown inFIG.8A). In an illustrative example (not illustrated), phases A1and A2are the same as B1and B2shown inFIGS.8A-8F, but are shifted 4 slots (e.g., A1phase lead starts in slot17rather than slot13as with B1phase lead), phases A3and A4are similarly the same as B3and B4but are shifted 4 slots (e.g., A3phase lead starts in slot28rather than slot24as with B2phase lead), phases C1and C2are the same as B1and B2but are shifted 8 slots (e.g., C1phase lead starts in slot21rather than slot13as with B1phase lead), and phases C3and C4are the same as B1and B2but are shifted 8 slots (e.g., C3phase lead starts in slot32rather than slot24as with B2phase lead). Based on the wiring path ofFIGS.8A-8F, Table 3 shows the number of unique hairpins (e.g., of each type and total number of different shapes).

FIGS.9A-9Fshow an illustrative wiring schematic corresponding to parallel windings of one phase of a ten-layer stator, with a winding pitch of six slots, in accordance with some embodiments of the present disclosure.FIGS.9A-9Fare arranged in a 2×3 array to form a composite table, withFIGS.9A-9Carranged in a 1×3 array, from left to right to form one table, and withFIGS.9D-9Farranged underneath in a 1×3 array, from left to right to form another table. The winding schematic ofFIGS.9A-9Fis arranged with the slots indexed along the horizontal axis and layers indexed along the vertical axis. The paths of windings B1, B2, B3, and B4are illustrated inFIGS.9A-9F(e.g., as windings901-904). As illustrated, hairpins are inserted axially from the bottom of each layer (e.g., the crown side, or lead side), with the leg(s) of the hairpin extending vertically in the corresponding slot(s). As illustrated, welds910between legs of hairpins are illustrated on the top (e.g., the weld side), shown by thick line segments. Based on the wiring path ofFIGS.9A-9F, Table 4 shows the number of unique hairpins (e.g., of each type and total number of different shapes).

FIGS.10A-10Fshow an illustrative wiring schematic corresponding to parallel windings of one phase of a six-layer stator, with a winding pitch of six slots, in accordance with some embodiments of the present disclosure.FIGS.10A-10Fare arranged in a 2×3 array to form a composite table, withFIGS.10A-10Carranged in a 1×3 array, from left to right to form one table, and withFIGS.10D-10Farranged underneath in a 1×3 array, from left to right to form another table. The winding schematic ofFIGS.10A-10Fis arranged with the slots indexed along the horizontal axis and layers indexed along the vertical axis. The paths of windings B1and B2are illustrated inFIGS.10A-10F(e.g., as windings1001-1002). As illustrated, hairpins are inserted axially from the bottom of each layer (e.g., the crown side, or lead side), with the leg(s) of the hairpin extending vertically in the corresponding slot(s). As illustrated, welds1010between legs of hairpins are illustrated on the top (e.g., the weld side), shown by thick line segments. In an illustrative example (not illustrated), phases A1and A2are the same as B1and B2but are shifted 4 slots (e.g., A1phase lead starts in slot17), and phases C1and C2are the same as B1and B2but are shifted 8 slots (e.g., C1phase lead starts in slot21). Based on the wiring path ofFIGS.10A-10F, Table 5 shows the number of unique hairpins (e.g., of each type and total number of different shapes).

FIGS.11A-11Fshow an illustrative wiring schematic corresponding to parallel windings of one phase of a ten-layer stator, with a winding pitch of seven slots, in accordance with some embodiments of the present disclosure.FIGS.11A-11Fare arranged in a 2×3 array to form a composite table, withFIGS.11A-11Carranged in a 1×3 array, from left to right to form one table, and withFIGS.11D-11Farranged underneath in a 1×3 array, from left to right to form another table. The winding schematic ofFIGS.11A-11Fis arranged with the slots indexed along the horizontal axis and layers indexed along the vertical axis. The paths of windings B1, B2, B3, and B4are illustrated inFIGS.11A-11F(e.g., as windings1101-1104). As illustrated, hairpins are inserted axially from the bottom of each layer (e.g., the crown side, or lead side), with the leg(s) of the hairpin extending vertically in the corresponding slot(s). As illustrated, welds1110between legs of hairpins are illustrated on the top (e.g., the weld side), shown by thick line segments. For example, the paths of windings B1-B4are illustrated inFIGS.1-3. In an illustrative example (not illustrated), phases A1and A2are the same as B1and B2but are shifted 4 slots (e.g., A1phase lead starts in slot17), phases A3and A4are the same as B3and B4but are shifted 4 slots (e.g., A3phase lead starts in slot17), phases C1and C2are the same as B1and B2but are shifted 8 slots (e.g., C1phase lead starts in slot21), and phases C3and C4are the same as B1and B2but are shifted 8 slots (e.g., C3phase lead starts in slot21). Based on the wiring path ofFIGS.11A-11F, Table 6 shows the number of unique hairpins (e.g., of each type and total number of different shapes).

FIGS.12A-12Fshows an illustrative wiring schematic corresponding to parallel windings of one phase of a six-layer stator, with a winding pitch of seven slots, in accordance with some embodiments of the present disclosure.FIGS.12A-12Fare arranged in a 2×3 array to form a composite table, withFIGS.12A-12Carranged in a 1×3 array, from left to right to form one table, and withFIGS.12D-12Farranged underneath in a 1×3 array, from left to right to form another table. The winding schematic ofFIGS.12A-12Fis arranged with the slots indexed along the horizontal axis and layers indexed along the vertical axis. The winding path of each winding of windings B1and B2are illustrated inFIGS.12A-12F(e.g., as windings1201-1202). As illustrated, hairpins are inserted from the bottom of each layer (e.g., the crown side, or lead side), with the leg(s) of the hairpin extending vertically in the corresponding slot(s). As illustrated, welds1210between legs of hairpins are illustrated on the top (e.g., the weld side), shown by thick line segments. For example, the winding paths of windings B1and B2are illustrated inFIGS.4-5. In an illustrative example (not illustrated), windings A1and A2(of phase A) are the same as B1and B2but are shifted 4 slots (e.g., A1phase lead starts in slot18), and windings C1and C2(of phase C) are the same as B1and B2but are shifted 8 slots (e.g., C1winding lead starts in slot22). Based on the wiring path ofFIGS.12A-12F, Table 7 shows the number of unique hairpins (e.g., of each type and total number of different shapes).

The illustrative winding arrangements ofFIGS.1-12Fshow some aspects of the present disclosure. For example, the specific slot numbering is only illustrative and the windings illustrated may start at any suitable slot location and layer. Further, the number of slots, number of poles, the number of phases, number of parallel windings in each phase, number of layers, the pole-pitch, or any combination thereof may be any suitable value in accordance with the present disclosure. In addition, whether each winding starts at the highest or lowest indexed layer is merely illustrative. In some embodiment, for example, the winding paths of B1and B2ofFIGS.9A-9Fcan start at the innermost layer as opposed to the outermost layer.

FIG.13shows a flowchart of illustrative process1300for making a motor stator having balanced windings, in accordance with some embodiments of the present disclosure. In an illustrative example, any of the stators or winding arrangements ofFIGS.1-12F, or any other suitable stator, may be wound using process1300. The illustrative steps of process1300may be performed in any suitable order, in accordance with the present disclosure. For example, steps1302and1308may be performed at the same time, sequentially in any suitable order, or a combination thereof. In a further example, step1310may be performed in increments (e.g., after each of steps1302-1308or at any suitable intermediate stage in assembly). Process1300may be repeated for each phase, each winding of each phase (e.g., where multiple windings are coupled in parallel to form a phase), or a combination thereof. To illustrate, each of windings B1-B4ofFIGS.1-3may be wound using process1300, and windings B1-B4may be electrically coupled in parallel to form the “B” phase of the motor (e.g., and process1300may be repeated for the “A” and “C” phases).

Step1302includes arranging a phase lead and a neutral lead in respective slots of a stator. In some embodiments, the phase lead and neutral lead are inserted into respective slots axially. In some embodiments, step1302includes bending the inserted leads after insertion (e.g., to position the ends of the leads for welding). In some embodiments, the phase lead and the neutral lead each include one leg, which is inserted into the respective slot.

Step1304includes arranging a first set of winding hairpins in respective slots of a stator, in a sequence along a first azimuthal orientation. In some embodiments, each winding hairpin is inserted into respective slots axially. In some embodiments, step1304includes bending the inserted leads after insertion (e.g., to position the ends of the leads for welding). The first azimuthal orientation may be either clockwise or counter-clockwise. In some embodiments, the first set of winding hairpins may include jumpers that span one or more layers. In some embodiments, the first set of winding hairpins each include the same span (e.g., span the same number of slots).

Step1306includes arranging a same-layer jumper hairpin in respective slots of a stator. In some embodiments, the same layer jumper is arranged in the radially innermost layer. In some embodiments, the same layer jumper is arranged in the radially outermost layer. The same-layer jumper may include the same span, a shorter span, or a longer span than the first set of winding hairpins.

Step1308includes arranging a second set of winding hairpins in respective slots of a stator, in a sequence along a second azimuthal orientation. In some embodiments, each winding hairpin is inserted into respective slots axially. In some embodiments, step1308includes bending the inserted leads after insertion (e.g., to position the ends of the leads for welding). The second azimuthal orientation may be either clockwise or counter-clockwise, whichever is opposite to the direction of step1304. In some embodiments, the second set of winding hairpins may include jumpers that span one or more layers. In some embodiments, the second set of winding hairpins each include the same span (e.g., span the same number of slots). In some embodiments, each winding hairpin of the first set and the second set include the same span (e.g., seven slots as illustrated inFIGS.1-5, or any other suitable number of slots).

Step1310includes welding legs of sequential winding hairpins together. Step1310may include contact welding, laser welding, friction welding, soldering, brazing, crimping, joining using any other suitable technique, or any combination thereof.

In an illustrative example, each winding applied using process1300may follow a path from outer to inner (e.g., and vice versa for10layer winding), then make a same layer jump, and then return back to the outer or inner by changing the winding direction (e.g., azimuthal direction), rather than starting at an outer or inner layer and ending at the opposite radial side (e.g., inner or outer, respectively). In a further illustrative example, for some ten-layer and eight layer arrangements, each the winding need not complete each layer before jumping to the next layer.