CN117200491A - Stator winding with upper and lower end turns for cross-over alignment - Google Patents

Abstract

The present application provides a stator winding having upper and lower end turns for cross-over alignment. The motor includes a stator core and windings. The stator core includes a plurality of radially extending teeth defining a number of slots in the stator core. The windings are positioned on the stator core and include a plurality of conductors that are connected together to provide a plurality of parallel paths for each phase of the windings. The windings define the number of conductor layers in each slot, the number of poles, and the number of slots per pole per phase. The winding includes a plurality of standard pitch end loops and a plurality of sets of upper and lower end loops. The plurality of crossover end loops of each of the plurality of parallel paths of each phase are substantially aligned in a radial direction on the stator core.

Description

Stator winding with upper and lower end turns for cross-over alignment

Cross Reference to Related Applications

The present application is a continuation-in-part application of U.S. patent application Ser. No. 17/833,368, filed on 6 at 2022, and also claims the benefit of U.S. provisional patent application Ser. No. 63/415,820, filed on 13 at 2022, 10, which is incorporated herein by reference in its entirety.

Technical Field

The present application relates to the field of electric machines, and more particularly to stator winding arrangements.

Background

The stator windings are provided in various configurations having different characteristics that provide different performance characteristics for the motor. Examples of different winding characteristics include the number of poles, the number of phases, the number of slots per pole per phase, the type of conductor, the number of conductor layers, the number of parallel paths per phase, the number of pole turns, and the type of connection between conductors, as well as any of a number of other winding characteristics.

The stator windings may be formed using different methods. For example, the stator windings may be formed from wire strands that are continuously wound around the stator core, or from a plurality of segmented conductors that are connected together on the stator core. The segmented conductor comprises two straight segments connected by an end loop. Thus, the segmented conductors are sometimes referred to as "hairpin conductors" or "U-turn conductors". To form the windings from the segmented conductors, the segmented conductors are axially inserted into slots of the stator core, the ends of the conductors are twisted, and the terminal portions of the branch ends are then connected together to form the path of the windings.

Segmented conductors are particularly advantageous when special connections between conductors are required to complete the winding. Segmented conductors come in a variety of different configurations, including conductors of different sizes, as well as conductors having different pitches defined by the end turn loops (i.e., the distance between straight segments of such conductors). The segmented conductors may be used to form any number of different winding arrangements based on the size and shape of the segmented conductors and the connections made between the segmented conductors.

In view of being able to form different winding arrangements with different performance characteristics, it is advantageous to provide an electric machine with a winding arrangement defined by a plurality of parallel paths, a plurality of windings (wrap) on pole sections, and sections of the paths connected in series. In addition, it would be advantageous if such a winding arrangement included unique performance characteristics and could be relatively simple to manufacture and produce without significantly increasing costs compared to other segmented winding arrangements. These and other features and advantages of the motor will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. Although it is desirable to provide an electric machine having a segmented conductor winding arrangement that provides one or more of these or other advantageous features that may be apparent to a person reading the present disclosure, the teachings disclosed herein extend to those embodiments that fall within the scope of the appended claims, regardless of whether they include or realize one or more of the advantages or features mentioned herein.

Disclosure of Invention

In at least one embodiment disclosed herein, a stator for an electric machine includes a stator core and a multi-phase winding positioned on the stator core. The stator core includes a plurality of teeth defining a slot number in the stator core. The multi-phase winding includes a plurality of segmented conductors connected together to provide a plurality of parallel paths for each phase of the winding, each conductor comprising: an end loop disposed on a crown end of the stator core, (ii) two branches extending through slots of the stator core, and (iii) two branch ends extending from the slots at a connection end of the stator core, each branch end having a twisted portion, wherein the branch ends of different conductors are connected together to form a multi-phase winding wound around the stator core. The windings define the number of conductor layers in each slot, the number of poles, the number of parallel paths per phase, and the number of slots per pole per phase. The end loops on the crown ends include a plurality of standard pitch end loops and a plurality of sets of upper and lower end loops (over-under loops). The plurality of crossover end loops of at least one of the plurality of parallel paths of each phase are substantially aligned in the radial direction on the connection end.

In at least one embodiment disclosed herein, an electric machine includes a stator core and windings. The stator core includes a plurality of radially extending teeth defining a slot number in the stator core. The windings are positioned on the stator core and include a plurality of conductors connected together to provide a plurality of parallel paths for each phase of the windings. The windings define the number of conductor layers in each slot, the number of poles, and the number of slots per pole per phase. The winding includes a plurality of standard pitch end loops and a plurality of sets of upper and lower end loops. The plurality of crossover end loops of each of the plurality of parallel paths of each phase are substantially aligned in a radial direction on the stator core.

Drawings

Fig. 1 is a perspective view of a welded end of a stator core with a segmented conductor winding arrangement positioned thereon.

Fig. 2 is a perspective view of an exemplary segmented conductor for forming the winding arrangement of fig. 1.

Fig. 3 is a tabular diagram of a segmented conductor winding configured for use in conjunction with the stator of fig. 1, wherein the number of pole turns of the winding is not divisible by the number of poles of the winding.

FIG. 4 is a table diagram of a first alternative embodiment of the segmented conductor winding of FIG. 3;

FIG. 5 is a table diagram of a second alternative embodiment of the segmented conductor winding of FIG. 3;

FIG. 6 is a side view of a standard end turn (6 pitch) and upper and lower end turns (7 pitch above 5 pitch) configured for use in the winding of FIG. 5;

FIG. 7 is a diagram illustrating a welding pattern between poles 4 and 5 of the winding of FIG. 5;

FIG. 8 is a table diagram of a third alternative embodiment of the segmented conductor winding of FIG. 3; and

fig. 9 is a side view of a standard end turn (9 pitch), first upper and lower end turn configuration (11 pitch over two 8 pitches) and second upper and lower end turn configuration (two 10 pitches over one 7 pitch) for the winding of fig. 8.

Detailed Description

Disclosed herein is a stator for an electric machine. The stator includes a stator core having windings formed thereon. The windings comprise conductors layered in slots of the stator core. The conductors are arranged such that the winding includes a plurality of phases, and a plurality of parallel paths of each phase with the conductors form a plurality of coils on the stator core. In at least some embodiments, the winding is further configured such that the number of pole turns of each parallel path of the winding is not divisible by the number of poles of the winding.

General construction of stator core with segmented conductor windings

Fig. 1 shows a perspective view of a stator 10 for an electric machine, the stator 10 comprising a stator core 12 on which windings 20 are formed. The stator core 12 is constructed of ferromagnetic material, typically formed from a plurality of steel plates that are stamped and stacked on top of each other to form a stacked stack. The stator core 12 is generally cylindrical in shape defined by a central axis 18, including an inner peripheral surface and an outer peripheral surface. The inner peripheral surface defines an Inner Diameter (ID) of the stator. The outer peripheral surface defines an Outer Diameter (OD) of the stator.

A plurality of teeth 14 are formed on the interior of stator core 12 and are directed toward central axis 18. Each tooth 14 extends radially inward and terminates at an inner peripheral surface. Axial slots 16 are formed between the teeth 14 in the stator core 12. Each groove 16 is defined between two adjacent teeth such that the two adjacent teeth form two opposed radial walls of one groove. Both the teeth 14 and the slots 16 extend from a first end 30 (i.e., "crown end") to a second end 32 (i.e., "connecting end" or "weld end") of the core.

Radial openings to the slots 16 are formed along the inner peripheral surface of the stator core 12. When the groove 16 is semi-closed, each radial opening to the groove 16 has a smaller width at the inner peripheral surface than at a more radially outer position (i.e., a groove position closer to the outer peripheral surface). In addition to the radial openings through the inner peripheral surface to the slots 16, axial openings to the slots 16 are provided at the opposite ends 30 and 32 of the stator core 12.

As shown in fig. 1, the stator core 12 is configured to retain the winding arrangement 20 within the slots 16 of the stator core 12. The winding arrangement 20 is formed from a plurality of interconnected coils held within the slots 16. The coils comprise interconnected conductor segments that extend through the slots and form a path generally around the core 12 on which the plurality of coils are formed. Each slot 16 is configured to hold a number of in-slot segments in a "layer" of slots, the in-slot segments typically being arranged in a single column such that each layer of slots holds a single conductor segment.

Segmented conductor for winding arrangement

Referring now to fig. 2, an exemplary segmented conductor 22 is shown separated from the winding arrangement 20. The segmented conductor 22 is formed from a length of conductive material such as copper. The exemplary segmented conductor shown in fig. 2 also has a rectangular cross-sectional shape.

Each segmented conductor comprises two branches 26, with the end loop 24 connecting the two branches 26. Each branch comprises a straight portion 27, a torsion portion 28 and a terminal portion 29. Both the straight portion 27 and the end portion 29 extend in the axial direction. The straight portion 27 is configured to extend axially through one slot of the stator core, and may also be referred to as an "in-slot portion". The torsion portion 28 has an axial direction component, a circumferential direction component, and a radial direction component, and extends between the straight portion 27 and the tip portion 29.

The end loops 24 (which may also be referred to as "end turns" or "U-turns") of each segmented conductor 22 are disposed on the crown end 30 of the core, define a 180 ° change in direction of the segmented conductor, and extend a circumferential distance associated with the number of slots of the stator core. This distance is called the "pitch" (P) of the end loop. The end loop pitch P is defined as the end loop connecting a straight line segment in a particular slot number (S) 1 with a straight line segment in slot p+s. For example, an 11-pitch end loop (i.e., p=11) is defined as connecting a straight line segment in slot 1 (i.e., s=1) in the core with a straight line segment in slot 12 (i.e., 11+1=12) in the core. In the exemplary conductor of fig. 2, the end loop 24 is shown as extending a distance equal to eleven slots of the core (i.e., p=11). Thus, as described in the above example, if the straight portion 27 of the first branch is positioned in the slot 1 of the core, the straight portion 27 of the second branch is positioned in the slot 12 of the core.

When forming the winding 20, the branches 26 are all initially straight and do not include the torsion portions 28. This allows the limb 26 to be inserted axially into the slot 16 of the core 12 with all end loops 24 arranged on the crown end 30 of the core, all straight portions 27 extending through the slot 16, and all terminal portions 29 arranged on the connecting end 32 of the core. For each segmented conductor, one limb is positioned in one layer of slots and the other limb is positioned in an adjacent layer of the other slot, with the two slots separated by the pitch of the end loops 24 on the crown end 30 of the core 12. After insertion into the slots, the ends of the branches 26 protrude axially from the connecting ends 32 of the stator core. Then, the ends of the branches 26 of each segmented conductor 22 are bent/twisted in opposite directions so that a twisted portion 28 is formed in each branch, with the twisted portion 28 of one branch extending in the opposite circumferential direction from the twisted portion 28 of the other branch. This circumferential distance spanned by each torsion portion 28 is related to the number of slots of stator core 12 and is referred to as the "twist" (T) of leg 26. In the exemplary conductor of fig. 2, each leg 26 has a twist of six slots. While twist is shown in fig. 2 as being in two opposite directions away from the central axis 19 of the segmented conductor for ease of illustration of the twist, it will be appreciated that the twist associated with the windings described herein, and in particular the windings of fig. 3, is actually in two opposite directions back toward the central axis 19 of the segmented conductor.

After twisting the branches 26, the end portions 29 of the different conductors are connected together (e.g., by welding or other connection method) at the connection ends 32 of the stator core 12 to complete the winding 20. At the same time, the torsions (T) of the two segmented conductors connected at their respective end portions 29 form an end loop defined by the pitch (P) on the welded end 32 of the stator core. Thus, it will be appreciated that the pitch of each end loop 24 at the crown end 30 is defined by the end loops of the associated segmented conductor 22, and the pitch of each end loop at the weld end 32 is defined by the two degrees of twist (T) of the two connected branch ends (i.e., the connected terminal portions 29 of the two branch ends).

While fig. 2 illustrates one exemplary embodiment of a segmented conductor for the winding arrangement 20, it will be appreciated that differently shaped conductor segments are also contemplated. For example, the pitch of the end loops 24 and the degree of twist of the branch ends may be different for different segmented conductors used in the winding arrangement 20. As another example, leads 40 to winding and/or bus bar connections may be provided in combination with elongated end portions 29 extending beyond other end portions on the weld ends 32 of the stator core 12.

With parallel paths and twistsWinding arrangement of segments

Referring now to fig. 3, a tabular diagram of a stator winding arrangement 20 is shown, wherein the winding arrangement is formed from a plurality of segmented conductors 22, as described above. As indicated in the top two rows of the table of fig. 3, the winding arrangement 20 includes six poles (as indicated by the six slot groups associated with each) and is configured for a stator core having seventy-two slots. As indicated in the leftmost column of fig. 3, the conductors of the winding (i.e. the straight portions 27 of the conductor branches) are arranged in a single column in eight layers (L) in each of the seventy-two slots. In the disclosed embodiment of the winding, layer 1 is the outer layer of each slot and layer 8 is the inner layer of each slot, but it will be appreciated that the winding may also be configured in an opposite arrangement, where layer 1 is the inner layer and layer 8 is the outer layer of the slot.

Only one phase of the winding is shown in fig. 3, and it will be appreciated that for a three-phase winding, the other two phases are identical to the one shown, but the further first phase moves across four slots and the further second phase moves across eight slots. Thus, while the table diagram of fig. 3 shows only three columns/slots between the slot groups of the illustrated phase for simplicity, it will be appreciated that eight slots are actually provided between each slot group.

As shown in fig. 3, each path of the winding includes six parallel paths (i.e., path a shown by numbers 1-32 in the slots and similarly configured paths B, C, D, E and F, as indicated in the table). The straight conductor portions of each path a-F are disposed in the slots as shown in fig. 3. For path a, the path starts in the slot identified by number "1" (via the end turns on crown end 30) jumps to the next slot identified by number "2" (via the end turns on connecting end 32) jumps to the next slot identified by number "3", and so on, until the path ends at the slot identified by number "32". Each of paths B, C, D, E and F also has thirty-two similarly configured conductors disposed in the slots. The leads 40 of each path are illustrated by a box having a bold/darkened outline. Thus, in the winding of fig. 3, the leads of path a extend from the connecting ends of the core at the slots of the conductors identified by the numbers "1" and "32".

The table of fig. 3 includes an upper portion 36 and a lower portion 38 to easily show the end loops of the windings. In both the upper 36 and lower 38 portions of the form, the lines extending between the groove sets represent the overall arrangement of the end circuits extending between the groove sets. The upper part 36 of the table shows the end loops 24 on the crown ends 30 of the stator core, where each end loop extends between two conductors in two different slots of the winding (i.e. each end loop is provided by a preformed end loop 24 of one segmented conductor 22). The lower part 38 of the table shows the end loops (i.e. the end loops formed by the connection between the twisted branch ends and the end portions 29) formed on the connection ends 32 of the stator core extending between the conductors in the respective slots for one phase of the winding. The lower portion 38 is a view from the crown end 30, looking through the stator at the connecting end 32. Also, each "end loop" (or "end turn") provides a connection between two conductor branches disposed in different slots. Examples of the end loops include an end loop formed by U-turn portions of a segmented conductor, an end loop formed by welded ends of branches of different segmented conductors, or a continuous wire bent to form an end loop at one end of a stator core.

In the upper part 36 of the table of fig. 3, the line 21 extending between the grooves represents the general arrangement of the end circuit 24 on the crown end 30, seen from the crown end. Each line 21 extending between the slot sets is associated with a set of four end loops of the crown end of the stator. For example, the top line 21a of the upper portion 36 of the table extending between the slot sets associated with poles 2 and 3 represents four different end loops extending between layers 1 and 2 for the path a conductor. Thus, line 21a represents the following four end loops:

a first end loop with a pitch of fifteen (15) extends between the conductor identified by the number "1" in the left slot group (i.e. in the slot group associated with pole 2) and the conductor identified by the number "2" in the right slot group (i.e. in the slot group associated with pole 3);

-a second end loop of pitch eleven (11) extends between the conductor identified by the number "3" in the left slot group and the conductor identified by the number "4" in the right slot group;

-a third end loop with a pitch of eleven (11) extends between the conductor identified by the number "5" in the left slot group and the conductor identified by the number "6" in the right slot group; and

a fourth end loop with a pitch of eleven (11) extends between the conductor identified by the number "7" in the left slot group and the conductor identified by the number "8" in the right slot group.

It will be appreciated that each set of four end loops (e.g., the end loops associated with line 21a, as described above) on crown end 30 define a set of upper and lower end loops extending between the two poles. In particular, each set of four end loops includes fifteen (15) pitch end loops extending over three staggered eleven (11) pitch end loops.

The lower portion 38 of the table of fig. 3 is similar to the upper portion 36, with the lines extending between the slot sets representing the overall arrangement of the associated connections between the branch ends and the degree of twist in order to form an end loop on the weld end 32 of the stator core 12. Each stub 23 extending horizontally from the slot set in the lower portion 38 of fig. 3 represents four different branch ends, each having a twist of six. Each ellipse 25 in the lower part 38 of fig. 3 represents a connection between two twisted branch ends. Thus, the two lines 23 and the three ellipses 25 of each group represent three end loops of one conductor path on the connecting end 32 of the stator core 12. For example, between pole 2 and pole 3, three end loops 24a include the following:

-a first end loop extending between the conductor identified by the number "2" in layer 2 of the right slot group and the conductor identified by the number "3" in layer 1 of the left slot group;

A second end loop extending between the conductor identified by the number "4" in layer 2 of the right slot group and the conductor identified by the number "5" in layer 1 of the left slot group; and

a third end loop extending between the conductor identified by the number "6" in layer 2 of the right slot set and the conductor identified by the number "7" in layer 1 of the left slot set.

In addition to the above, the oval at end loop 24b represents a special crossover connection between the conductor identified by the number "8" in layer 2 of the right slot set and the conductor identified by the number "9" in layer 3 of the left slot set.

As shown in fig. 3, most of the end loops 24 on the connecting ends 32 of the stator core are regular end turns 24a, where each regular end turn connects two straight conductor segments within the same layer pair (e.g., the end loop 24 connecting the path a conductor identified by the number "2" in layer 2 to the path a conductor identified by the number "3" in layer 1 is a regular end turn with a pitch of 12). However, in addition to the regular end turns 24a extending between the conductors in the same layer pair, the end turns on the connection end 32 also include a set of jumper end turns 24b, where each jumper end turn connects one conductor in one layer pair to one conductor in an adjacent layer pair (e.g., the end loop connecting the path A conductor identified by the number "8" in layer 2 of the right slot set with the conductor identified by the number "9" in layer 3 of the left slot set is a jumper end turn; thus, as used herein, the term "jumper" end turn refers to an end turn connecting conductors in two different layer pairs of the winding). Each path of each phase includes two crossovers end turns 24b. With respect to path a, the crossover end turns include a first crossover end turn that extends between pole 2 and pole 3 and connects the conductor in layer 2 to the conductor in layer 3, and a second crossover end turn that extends between pole 5 and pole 6 and connects the conductor in layer 6 to the conductor in layer 7.

In addition to bridging the end turns 24b, the winding also includes one bus bar 34 for each path of each phase. Similar to the crossover end turns 24b, each bus bar 34 provides a connection between conductors in two adjacent layer pairs, particularly between conductors in layer 4 and conductors in layer 5 of a given path. However, the bus bar 34 extends a significantly greater number of slots than the number of slots extending across the end turns 24b (which have a pitch of 12). For example, in fig. 3, the bus bar connections of path a extend a total of 24 slots from the conductor identified as "16" in layer 4 to the conductor identified as "17" in layer 5, and thus, the bus bar 34 extends twice as many slots across the end turns 24 b.

The bus bar 34 provides an inconveniently formed connection between the conductors in layers 4 and 5 of the winding between two adjacent branch ends. Thus, the terminal portions of the branch ends connected to the bus bar 34 may extend axially beyond other terminal portions (e.g., the terminal portions of the conductors identified as "16" and "17" in fig. 3 may extend axially beyond other nearby conductors, such as those identified as "14" and "23"). The bus bars 34 can be easily connected to these branch ends and routed in a circumferential manner over (i.e., at locations axially outward from) the other branch ends that form the end turns 24 at the connection ends 32 of the core 12.

To form the winding of fig. 3, the segmented conductors are inserted axially into slots 16 of core 12 from crown end 30. Thus, the preformed end turns 24 of each segmented conductor are located on the crown ends 30, the branches of the segmented conductor extend through two different layers of two different slots of the core, and the branch ends extend axially outward at the connecting ends 32 of the core. The branches at the connected ends of the core are then twisted and adjacent end portions 29 of the branches are connected together to form regular end turns 24a and bridging end turns 24b at the connected ends of the core. Thereafter, bus bar 34 is connected to the remaining branch ends configured to provide a bus bar connection between conductors extending from layers 4 and 5.

As previously described, the winding includes six paths (i.e., paths A, B, C, D and E), each configured similarly to path a, but displaced by a certain number of slots on the core. As shown in fig. 3, path a begins with lead 40 on connection end 32 extending from the conductor identified as "1". Conductor "1" extends through the core and on the opposite end (i.e., on crown end 30), fifteen pitch upper end turns connect conductor "1" to conductor "2". Conductor "2" then extends through the core to connecting end 32, at which connecting end 32 the branched end of conductor "2" is twisted six slots to the left and welded to the branched end of conductor "3" twisted six slots to the right so that twelve pitch end turns are formed on the connecting end between conductor "2" and conductor "3". Conductor "3" then extends through the core back to crown end 30 where it connects to an 11 pitch end loop that connects conductor "3" to conductor "4". This pattern of twelve pitch end loops on the connection end 32 and eleven pitch end loops on the crown end 30 is then repeated until conductor "8" is reached. It will be appreciated that the pattern of conductors "1" - "8" forms the first coil on the stator core with the straight conductor portions extending through the slots associated with poles 2 and 3, with the end turns 24 extending between the straight portions.

At conductor "8", the branch end is twisted left by six slots on the connection end 32, and welded to the branch end of conductor "9" twisted right by six slots. This forms a twelve pitch crossover end loop on the connection end that extends between layers 2 and 3 (and thus connects the first layer pair to the second layer pair). The pattern of conductors "1" through "8" described above is repeated for each of conductors "9" through "16" except that the conductors are disposed in layers 3 and 4. Thus, conductors "1" - "8" form a first coil on the stator core and conductors "9" - "16" form a second coil on the stator core. It will be appreciated that both the first coil and the second coil are associated with the same pair of poles (i.e., pole 2 and pole 3). It will also be appreciated that both the first coil and the second coil have a plurality of straight portions 27 located in one pole (i.e., pole 2) and a plurality of straight portions located in the other pole (i.e., pole 3).

At conductor "16", bus bar 34 connects conductor "16" in layer 4 to conductor "17" in layer 5 (conductor "17" is shifted twenty-four slots from conductor "16" as described above). The pattern of conductors "1" - "16" is then repeated as with conductors "17" - "32" except that conductors are now disposed in layers 5-8 instead of layers 1-4). At conductor "32", the path ends at lead 40. It will be appreciated that the pattern of conductors "17" - "24" forms a third coil on the stator core and the pattern of conductors "25" - "32" forms a fourth coil on the stator core. The third and fourth coils are both associated with the same pair of poles (i.e., pole 5 and pole 6). The coils define four different sections of each parallel path, including a first section defined by a first coil, a second section defined by a second coil, a third section defined by a third coil, and a fourth section defined by a fourth coil.

As described herein, the winding arrangement of fig. 3 is configured as a three-phase six (6) pole winding having six (6) parallel paths per phase. The windings are arranged on a stator core having seventy-two (72) slots. The winding comprises eight (8) conductors per slot, with eight conductor layers in each slot. In this way, conductors are arranged in a single column in each slot. The winding is defined by four (4) slots per pole per phase (i.e., 72 slots/(6 poles×3 phases) =72/18=4 slots per pole per phase). The windings are also defined by sixteen turns (PT). The pole wire turns for a given winding refer to the number of slots per parallel path (SS) divided by 2 (i.e., pt=ss/2), where SS equals the number of straight conductor segments extending through the core in each parallel path. Thus, in the example of the winding of fig. 3, ss=32, as indicated by conductors "1" - "32" through path a. Thus, for the winding of fig. 3, the number of pole turns (per parallel path) is 16 (i.e., pt=ss/2=32/2=16).

In view of the above, it will be noted that the winding of fig. 3 is configured such that the number of pole turns is not divided by the number of poles. Specifically, the number of turns of the polar line is sixteen (16), and the number of poles is six (6), thusThus, it will be noted that dividing the number of pole turns of each parallel path of the winding by the number of poles returns a mixed number (i.e., a number that is non-integer, so it includes both integers and appropriate fractions). The winding arrangement provides a unique configuration in which the number of turns of the pole wire for each parallel path of the winding is not an integer, thus providing a winding with unique and specialized performance characteristics that are not common to other winding arrangements.

Although embodiments of winding arrangements are disclosed herein, it will be appreciated that other embodiments are possible. For example, while the winding arrangements disclosed herein have been described in connection with segmented conductors having welded end loops at the connection ends, in at least some embodiments the winding arrangements may be formed with continuous wire segments (e.g., the entire path a of a given phase may be formed from one continuous wire). In this case, different degrees of torsion can be formed in the end loop by the end loop forming machine. In other embodiments, any number of different winding characteristics may be varied, for example, the number of poles of the winding, the number of pole turns of the winding may be different from sixteen, the number of parallel paths, and the number of slots per pole per phase.

First alternative embodiment of winding

A first example of an alternative embodiment of a winding arrangement is disclosed in fig. 4. The winding of fig. 4 is somewhat similar to the winding described in fig. 3, but with the significant difference of providing a winding with different features than in fig. 3. Only one phase of the winding is shown in fig. 4, and it will be appreciated that for a three-phase winding, the other two phases are identical to the one shown, but the further first phase moves across two slots and the further second phase moves across four slots.

The top 46 of the table in fig. 4 is a view of the end loop extending between the stator slots with the leads facing into the page. The straight portions of the segmented conductors are numbered 1-64 within the frames of the table, where each frame represents a straight portion of the segmented conductor in one layer of one slot. The wire between the frames is the end loop 24 connecting the straight portions of the conductors. The bottom 48 of the table in fig. 4 is a view from the end loop end, looking through the stator at the weld end. Likewise, an ellipse represents a welded portion at the connecting end portion of the stator core.

As indicated in the top two rows of the table of fig. 4, the winding arrangement 20 includes eight poles (as indicated by the eight slot groups associated with each) and is configured for a stator core having forty-eight slots. As indicated in the leftmost column of fig. 4, the conductors of the winding (i.e. the straight portions 27 of the conductor branches) are arranged in a single column in eight layers (L) in each of the seventy-two slots. Each pole of the winding extends across three slots (per phase). For example, pole #1 is disposed in slots 1, 2, and 3, pole #2 is disposed in slots 7, 8, and 9, and pole #3 = slots 13, 14, and 15.

As shown in fig. 4, each path of the winding includes two parallel paths (i.e., path a and path B). Each parallel path is similarly constructed, with the first parallel path (path a) moving one pole from the second parallel path (path B). For path a, starting with the lead identified by number "1" at layer 1 of slots 19, the path jumps (via the end turns on crown end 30) to the next slot identified by number "2" in layer 2 of slots 13, jumps (via the end turns on connecting end 32) to the next slot identified by number "3" in layer 1 of slots 7, and so on, until the path terminates at the slot identified by number "64" at layer 8 of slots 26. Similarly, path B starts with the lead identified by the number "1" at layer 1 of slot 25 and ends with the lead identified by the number "64" at layer 8 of slot 32.

As can be seen in fig. 4, the winding has two slots per pole per phase. The standard end loop pitch of the winding is 6. For example, the end loop connecting the segment identified by the number "1" in slot 25 to the segment identified by the number "2" in slot 19 is a six-pitch end loop (i.e., 25-19 = 6). All end loops at the crown end 30 and the connecting end 32 are six pitch end turns unless otherwise stated.

The winding of fig. 4 includes one short pitch jumper end turns 42 per path to create a phase shift. The short pitch end turns 42 are located between layers 4 and 5 on the mid-connection end 32 of the winding and between the conductor segments identified by the numbers "32" and "33". In the bottom 48 of the table of fig. 4, the two short-pitch end turns 42 are also identified by the number "5" in the oval located between the conductor segments identified as numbers "32" and "33".

In addition to the standard and short pitch end loops, the winding of fig. 4 also includes a series of upper and lower end loops 24c on the crown end 30 of the stator, the end loops 44 being labeled "7-5" in the upper portion of the table of fig. 4 to represent the seven pitches of the upper end loop and the five pitches of the lower end loop (and each pair of associated seven pitch five pitch end loops defining a "set" of upper and lower end loops). For these end circuits 44, the upper end circuit is fully across the lower end circuit. For example, for path A, a five-pitch end loop connects the segment labeled "7" in layer 1 of slot 37 to the segment labeled "8" in layer 2 of slot 32, and a seven-pitch end loop connects the segment labeled "15" in layer 1 of slot 38 to the segment labeled "16" in layer 2 of slot 31. The upper and lower end loops are configured to achieve such a long/short pitch arrangement (i.e., seven pitch end loops directly span five pitch end loops).

To further describe the windings of fig. 4, a detailed description of one of the two parallel paths (path B) is now provided. The path begins with the lead to the segment of slot identified as number "1" at layer 1 of slot 25. The end circuit connects the slot segment 1 to the slot segment "2" accommodated in layer 2 of the slot 19 on the crown end 30 side of the stator. From slot segment "2", the end loop on connecting end 32 connects slot segment "2" to slot segment "3" at layer 1 of slot 13. This pattern continues, alternating around the core until slot segment "7" in layer 1 of slots 37.

At slot segment "7", a five pitch (lower) end loop connects slot segment "7" with slot segment "8" in layer 2 of slots 32. Continuing from slot segment "8", an end loop (which may also be referred to herein as a "weld loop") at connecting end 32 connects slot segment "8" with slot segment "9" that is received in layer 1 of slot 26. This completes one winding on the stator.

After the first winding on the stator, an end loop at the crown end 30 (which may also be referred to herein simply as an "end loop") connects slot segment "9" in layer 1 of slots 26 with slot segment "10" in layer 2 of slots 20. The welding circuit connects the slot segment "10" with the slot segment "11" which is received in the layer 1 and slot 14. This pattern again continues until slot segment "15" at layer 1 of slot 38 is reached. At slot segment "15", a 7-pitch end loop connects slot segment "15" with slot segment "16" housed in layer 2 of slot 31. This completes a second winding (or "turn") on the stator core for the path. The crossover end loop 24b connects the slot segment "16" with the slot segment "17" that is received in layer 3 of slot 25. This completes path a for the layer pair associated with layer 1 and layer 2 and crosses over end loop 24b to transition the path to the next layer pair associated with layer 3 and layer 4.

From the groove section "17", the end circuit connects the groove section "17" to the groove section "18" accommodated in the layer 4 of the groove 19. This path continues in layers 3 and 4 (similar to the way it was wound twice in layers 1 and 2) to complete the third winding and the fourth winding ending in slot segment "32" in layer 4 of slot 31.

At slot segment "32", a short five-pitch crossover weld loop connects slot segment "32" with slot segment 33 in layer 5 of slot 26. The short pitch 5 produces a phase shift or 4-8-4 slot pattern. While a short five-pitch weld loop is used to create the phase shift, in at least one alternative embodiment, a seven-pitch end loop is utilized in place of a five-pitch end loop to create the phase shift or 4-8-4 slot pattern.

Similar to the four previously described windings, the fifth winding and the sixth winding are completed in layers 5 and 6. The sixth winding terminates at slot segment "48" in layer 6 of slot 32. The groove segment "48" of layer 6 is then connected to the groove segment "49" in layer 7 of groove 26 using a crossover weld loop. Thereafter, the seventh winding and the eighth winding are similarly completed in the layers 7 and 8. The winding then ends at slot segment "64" in layer 8 of slot 32.

As can be seen in fig. 4, the crossover end loops that transition the winding paths between the layer pairs (i.e., provide connections between (i) layer 1/2 and layer 3/4, (ii) layer 3/4 and layer 5/6, and (iii) layer 5/6 and layer 7/8) are conveniently aligned between poles. For example, for path a of fig. 4, the crossover end loops are all positioned between poles 4 and 5 on the connecting ends of the stator core. In other words, the welds that connect the branch ends that form the crossover end loop are all aligned in the radial direction between the two poles of the path. While the actual welds that connect the branch ends that form the crossovers end turns may not be perfectly aligned in the radial direction, they are all substantially aligned in the radial direction such that all of the welds that form a given path that bridge the end turns are all disposed between the two poles (e.g., the welds may be offset from the radial by an amount (e.g., 10 ° -30 °), but still disposed radially continuously on the winding at locations between the two poles for the path). This arrangement of aligned bridging end turns on the weld end 32 is facilitated at least in part by the upper and lower end turns 24c on the crown end 30.

Second alternative embodiment of winding

A second example of an alternative embodiment of a winding arrangement is disclosed in connection with fig. 5 to 7. The winding arrangement of fig. 5 is substantially the same as the winding arrangement of fig. 4, but the arrangement of fig. 5 does not include a short five pitch weld loop that provides the phase shift arrangement of fig. 4. This is particularly advantageous when an 8-8 slot mode is required instead of the 4-8-4 (phase shift) slot mode of fig. 4. In this case, the standard six pitches replace the five-pitch short pitch of fig. 4 described previously. A table diagram of a winding with an 8-8 slot pattern is shown in fig. 5. Again, the winding arrangement of fig. 5 is substantially the same as that of fig. 4 except that a standard six-pitch welded end loop is used for all of the crossovers end turns in fig. 5, as opposed to the two short five-pitch crossovers end turns of fig. 4. This results in the 8-8 slot pattern shown in the table diagram of fig. 4. All other connections (including upper and lower seven/five pitch end turns on crown end 30 and standard pitch end turns) and lead locations remain the same.

Fig. 6 is a radial/side view showing the configuration of the end turns on the crown end of the winding arrangement of fig. 5. As shown on the left side of fig. 6, two standard six-pitch end turns 24 are shown in a staggered relationship with one standard end turn and an adjacent standard end turn. In contrast, the right side of FIG. 6 shows a pair of upper and lower end loops 24c with a seven-pitch upper end loop extending entirely over and across the five-pitch end turns.

Fig. 7 shows a welding pattern diagram of the winding of fig. 5. This view is from the crown end 30 of the stator looking completely through the stator to the connection at the connection end 32. The rectangles in fig. 7 represent branches of various conductors, and the ellipses represent soldered portions connecting the ends of the branches. The numbers in the rectangle are the slot segments associated with the particular conductors in the table diagram of fig. 5. For example, slot segment "1" of layer 1 of slots 19 is a lead on the connecting end 32 of the stator. The slot segment "9" in layer 1 of slot 20 exits the slot and twists three slots to the right at the connecting end 32 of the stator, while the slot segment "8" in layer 2 of slot 26 exits the slot and twists three slots to the left. After twisting, slot segment "9" of layer 1 is aligned with slot segment "8" of layer 2 at a location between poles 4 and 5 on connecting end 32. As shown in fig. 7, the branches of the groove segments "8" and "9" are welded together, as indicated by the ellipse between the two groove segments. Similarly, slot segment "17" in layer 3 of slot 19 exits the slot and twists three slots to the right, while slot segment "16" in layer 2 of slot 25 exits the slot and twists three slots to the left. The branches of the groove segments "16" and "17" are welded together as shown by the oval between the two groove segments in fig. 7. Similar twist and weld connections are also provided for each of the groove segments "24" and "25", "32" and "33", etc., as shown in fig. 7. With this pattern, the slot segments in layer 1, layer 3, layer 5 and layer 7 twist three slots to the right and the slot segments in layer 2, layer 4, layer 6 and layer 8 twist 3 slots to the left.

It will be appreciated that the numbered slot segments in FIG. 7 are associated with path A, showing a plurality of bridging end turns 24b providing a connection between the layer pairs (i.e., a weld between "16" and "17" connects layer pair 1-2 to layer pair 3-4, a weld between "32" and "33" connects layer pair 3-4 to layer pair 5-6, and a weld between "48 and 49" connects layer pair 5-6 to layer pair 7-8). These welds of the cross-over end turns are all aligned in the radial direction while also being staggered relative to adjacent welds that provide regular end turn connections 24a within a layer pair (e.g., cross-over end turn connections 24b between "16" and "17" are staggered relative to regular end turn connections 24a between "8" and "9" and "24" and "25" in the circumferential direction). In the arrangements of fig. 5 and 7, all welds for the crossovers of path a are all disposed between poles 4 and 5, and all welds for the crossovers of path B are all disposed between poles 5 and 6. Thus, adjacent welds between the poles are all staggered (i.e., not circumferentially aligned) in the circumferential direction.

While the end turns are offset in the circumferential direction from the welds of adjacent crossovers, it will be appreciated that the welds of regular end turns 24a not associated with adjacent crossovers 24b are all aligned in the circumferential direction. For example, as can be seen in fig. 5 and 7, all of the end turns between poles 3 and 4 are aligned, and all of the end turns between poles 7 and 8 are also aligned. This arrangement with aligned regular end turns 24a between most poles and few staggered end turns for the crossover connection 24b between a few poles is advantageous because it facilitates quick and convenient welding of the branch ends at the connection ends of the stator during assembly. Thus, the disclosed winding arrangement not only provides advantageous features within the stator, but is also relatively easy to manufacture.

Third alternative embodiment of winding

A third example of an alternative embodiment of the winding arrangement is disclosed in connection with fig. 8 and 9. Fig. 8 shows a table diagram of this third alternative embodiment of the winding. The winding of fig. 8 is similar to the windings of fig. 4 and 5, but with some significant differences. As shown in fig. 8, the winding is configured as a three slot-per-pole-per-phase (SPPPP) winding, as opposed to the 2SPPPP of fig. 4 and 5. The winding of fig. 8 also has only six poles.

For the winding arrangement of fig. 8, the standard end turns 24a have a pitch of nine (standard pitch = 9) and the upper and lower end turns 24c have pitches of eleven (upper), eight (lower # 1) and eight (lower # 2), respectively (i.e., there are two eight-pitch lower end turns and one eleven-pitch upper end turn, with the eleven-pitch upper end turns spanning the two eight-pitch lower end turns). An example showing the arrangement of one upper/two lower end turns is shown at layers 1 and 2, between poles 3 and 4 of fig. 8. In this position, the eleven pitch end turns connect slot segment "17" in layer 1 of slots 34 to slot segment "18" in layer 2 of slots 23; eight pitch end turns connect slot segment "11" in layer 1 of slots 33 to slot segment "12" in layer 2 of slots 25; eight pitch end turns connect slot segment "5" in layer 1 of slots 32 to slot segment "6" in layer 2 of slots 24.

Fig. 9 is a radial/side view showing the configuration of the end turns on the crown ends of the winding arrangement of fig. 8. As shown on the left side of fig. 9, three standard nine-pitch end turns 24a are shown in a relationship in which each standard end turn is staggered from an adjacent standard end turn.

The middle view of fig. 9 shows a set of three upper and lower end loops 24c, with eleven-pitch upper end loops extending entirely above two eight-pitch end loops, which are interleaved with each other in adjacent slots and layers. As shown in the middle of fig. 9, the eleven-pitch end loop spans two eight-pitch end loops.

The right side of fig. 9 shows an alternative arrangement for the upper/lower end loop 24c of the winding of fig. 8. In this arrangement, there are two ten-pitch upper end loops and one seven-pitch lower end loop. Two ten-pitch upper end loops are interleaved and span one seven-pitch end loop.

Additional embodiments

While various embodiments of a stator winding having upper and lower end turns for cross-over alignment have been disclosed herein, it will be appreciated that many additional embodiments are possible. Examples of additional alternative embodiments include the following:

-fewer conductors per slot (e.g. 2) or more conductors per slot (e.g. 10);

the weld may be a continuous end loop on both ends (rather than one axial end being a welded end loop as may be found in hairpin stators);

there may be more per-phase per pole Slots (SPPPP), for example 4;

for 4SPPPP, the standard pitch = 12 and the up-down pitch = one 15 pitches above three 11 pitches;

for 4SPPPP, the upper and lower end loop pitch may alternatively be three 13 pitches above 1 9 pitches;

for 2SPPPP, the design shown has one 7 pitch over 5 pitch end loop area for each winding of 360 degrees of two conductor windings. As an embodiment, the number of end loops with 7 pitches above 5 pitches must be an odd number for each winding of 2 wires. So one, three, five … …, etc. for each winding;

for 3SPPPP, there are 1 or a multiple of 3+1 upper end loop areas required for each winding of three conductors. Thus, for example, 1, 4, 7 … …, etc.; and

for 4SPPPP there should be 1 or a multiple of 4 +1 upper end loop regions, e.g. 1, 5, 9 … …, etc., for each winding of four conductors.

Although exemplary embodiments of the present invention have been disclosed herein, those skilled in the art will appreciate that other implementations and adaptations are possible. Furthermore, aspects of the various embodiments described herein may be combined with or substituted for aspects from other features to obtain embodiments different from those described herein. Thus, it will be appreciated that the various features and functions disclosed above and others, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by any final appended claims.

Claims (20)

1. A stator for an electric machine, comprising:

a stator core comprising a plurality of teeth defining a number of slots in the stator core; and

a multi-phase winding positioned on the stator core, the winding comprising a plurality of segmented conductors connected together to provide a plurality of parallel paths for each phase of the winding, each conductor comprising (i) an end loop disposed on a crown end of the stator core, (ii) two branches extending through the slots of the stator core, and (iii) two branch ends extending from the slots on a connecting end of the stator core, each branch end having a twisted portion, wherein branch ends of different conductors are connected together to form the multi-phase winding wound on the stator core;

Wherein the windings define the number of conductor layers in each slot, the number of poles, a plurality of parallel paths per phase, and the number of slots per phase per pole;

wherein the end loops on the crown end include a plurality of standard pitch end loops and a plurality of sets of upper and lower end loops; and is also provided with

Wherein a plurality of crossover end loops for at least one of the plurality of parallel paths for each phase are substantially aligned in a radial direction on the connection end.

2. The stator of claim 1, wherein the standard pitch end loops have a pitch of n, wherein each set of upper and lower end loops includes one upper end loop having a pitch of n+1 and one lower end loop having a pitch of n-1.

3. The stator of claim 2, wherein the crossover end loop has a pitch of n, n+1 or n-1.

4. A stator according to claim 3, wherein n = 6.

5. The stator of claim 1, wherein the number of conductor layers is 8.

6. The stator of claim 1, wherein the plurality of parallel paths for each phase are defined by two parallel paths for each phase.

7. The stator of claim 1, wherein the number of slots per pole per phase is 2.

8. The stator of claim 1, wherein the number of slots per pole per phase is 3.

9. The stator of claim 8, wherein the standard pitch end loops have a pitch of n, and wherein each set of upper and lower end loops comprises one upper end loop having a pitch of n+2 and two lower end loops having a pitch of n "1, wherein the two lower end loops are staggered, and wherein the one upper end loop spans the two lower end loops.

10. The stator of claim 8, wherein the standard pitch end loops have a pitch of n, and wherein each set of upper and lower end loops comprises two upper end loops having a pitch of n+1 and one lower end loop having a pitch of n-2, wherein the two upper end loops are staggered and span the lower end loops.

11. An electric machine, comprising:

a cylindrical stator core comprising a plurality of radially extending teeth defining a number of slots in the stator core; and

a winding positioned on the stator core, the winding comprising a plurality of conductors connected together to provide a plurality of parallel paths for each phase of the winding, wherein the winding defines a number of conductor layers in each slot, a number of poles, and a number of slots per pole per phase;

Wherein the winding comprises a plurality of standard pitch end loops and a plurality of groups of upper and lower end loops; and is also provided with

Wherein a plurality of crossover end loops for each of the plurality of parallel paths for each phase are substantially aligned in a radial direction on the stator core.

12. The electric machine of claim 11 wherein the standard pitch end loops have a pitch n, wherein each set of upper and lower end loops includes one upper end loop having a pitch n+1 and one lower end loop having a pitch n-1.

13. The electric machine of claim 12, wherein the crossover end loop has a pitch of n, n+1 or n-1.

14. The electric machine of claim 13, wherein n = 6.

15. The electric machine of claim 11, wherein the number of conductor layers is 8.

16. The electric machine of claim 11, wherein the plurality of parallel paths for each phase are defined by two parallel paths for each phase.

17. The electric machine of claim 11, wherein the number of slots per pole per phase is 2.

18. The electric machine of claim 11, wherein the number of slots per pole per phase is 3.

19. The electric machine of claim 18, wherein the standard pitch end loops have a pitch of n, and wherein each set of upper and lower end loops comprises one upper end loop having a pitch of n+2 and two lower end loops having a pitch of n-1, wherein the two lower end loops are staggered, and wherein the one upper end loop spans the two lower end loops.

20. The electric machine of claim 18, wherein the standard pitch end loops have a pitch of n, and wherein each set of upper and lower end loops comprises two upper end loops having a pitch of n+1 and one lower end loop having a pitch of n-2, wherein the two upper end loops are staggered and span the lower end loops.