Abstract
A polyphase stator or rotor winding with high configurability is provided. A stator or rotor using the polyphase stator or rotor winding with high configurability, where single-layer hairpins having different pitches so as to differ at least by two positions in the slot is also provided. Such an arrangement allows obtaining a wider family of windings and electrically balanced stators or rotors, maintaining the diameter at the air gap, the number of slots, and the dimensions of the conductor.
Claims
1. A polyphase bar stator or rotor winding, comprising two or more layers of basic conductors, the basic conductors comprising a head end connecting two legs, each leg having a corresponding free end, each layer consisting of a circumferential arrangement of the basic conductors wound about a central winding axis, a distal layer and a proximal layer being defined with respect to said winding axis, wherein the legs of the basic conductors cross predetermined volume units which are circumferentially adjacent in each layer and radially corresponding between layers to form a radial series of volume units, an angular distance covered by each basic conductor with respect to said winding axis being measured in terms of number of volume units circumferentially covered between said two legs and being referred to as pitch, wherein: the head ends of the basic conductors are all on a first side with respect to a direction of the winding axis and the free ends are all on a side opposite to said first side; the basic conductors in said winding are electrically connected from said side opposite to the first side to form a plurality of single-phase pathways; the polyphase stator or rotor winding comprises a plurality of single-layer basic conductors configured so that the two legs thereof are positioned in the volume units of a same layer; and at least one of the pathways of said plurality of single-phase pathways comprises one or more distal single-layer basic conductors positioned in the distal layer and having a first pitch and one or more respective proximal single-layer basic conductors positioned in the proximal layer and having a second pitch; and wherein said first pitch and said second pitch differ by two or more volume units.
2. The polyphase stator or rotor winding of claim 1, wherein said first pitch and said second pitch differ by two volume units.
3. The polyphase stator or rotor winding of claim 1, wherein said first pitch and said second pitch differ by three volume units.
4. The polyphase stator or rotor winding of claim 1, wherein all the pathways of the plurality of single-phase pathways comprise one or more distal single-layer basic conductors with a first pitch and one or more proximal single-layer basic conductors with a second pitch.
5. The polyphase stator or rotor winding of claim 1, wherein said basic conductors comprise nested basic conductors.
6. The polyphase stator or rotor winding of claim 1, wherein said plurality of basic conductors comprise stranded basic conductors.
7. The polyphase stator or rotor winding of claim 1, wherein at least one of the one or more distal single-layer basic conductors and/or at least one of the one or more proximal single-layer basic conductors have the two free ends angled in opposite circumferential directions.
8. The polyphase stator or rotor winding of claim 1, wherein at least one of the basic conductors other than the single-layer basic conductors has a pitch corresponding to one of said first and second pitches.
9. The polyphase stator or rotor winding claim 1, wherein at least one intermediate layer is interposed between said distal layer and said proximal layer.
10. The polyphase stator or rotor winding 1, wherein the polyphase stator or rotor winding is devoid of jumpers.
11. A stator or rotor for an electric machine, comprising a core with a series of slots and at least one winding of conductors inserted into said slots, wherein said at least one winding of conductors is the polyphase stator or rotor winding of claim 1.
12. An electric machine comprising the stator or rotor of claim 11.
Description
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
List of Figures
[0051] The invention will now be described by way of non-limiting example, with particular reference to the figures of the accompanying drawings, in which:
[0052] FIG. 1 shows in (a) a preformed flattened U-shaped hairpin and, in (b), a formed hairpin, according to the prior art;
[0053] FIG. 2 shows in (a) a molded conductor, and in (b) a conductor after being subjected to a welding-side twisting;
[0054] FIG. 3 shows the hairpin in 2(a) from the top, according to the prior art;
[0055] FIG. 4A shows in (a) a stranded hairpin with reversal of the cross-section at the bending point and, in (b), with continuous transposition along the portions of the hairpin housed in a slot, according to the prior art;
[0056] FIG. 4B shows a stranded type of hairpin;
[0057] FIG. 4C shows, in (a)-(c), three possible arrangements of the hairpin legs of a double-crown winding in various positions in the slot; A and B indicate the crown to which the legs shown in the slot belong (belonging to different hairpins);
[0058] FIG. 4D shows an example of an inversion hairpin, according to the prior art;
[0059] FIG. 4E shows in (a) an example of a hairpin nested on different layers and in (b) an example of a hairpin nested on the same layer, according to the prior art;
[0060] FIG. 4F shows an example of use of a jumper, according to the prior art;
[0061] FIG. 5 shows an example of a single-layer hairpin, according to the prior art;
[0062] FIG. 6 shows, in (a), a winding pattern linear representation of a stator with 24 slots, 4 layers and 2 pole pairs. The position of the conductors associated with each phase can be identified by means of the letters U, V and W, respectively (the phase is further indicated by the background of the cell: diagonal bar towards the left for U, no background for W and diagonal bar towards the right for V), while the mark following the letter identifies the direction of the current in a determined moment in time t and can be represented by a normal versor on the sheet; and in (b) a planar representation of the stator with only one coil, having the legs or semi-coils in slot 1 and slot 7, respectively (the phases are indicated by the same graphical convention as the cells in (a)), according to an example of the prior art;
[0063] FIG. 7 shows the construction of a pathway, starting from basic conductor semi-coils, where, in (a) the slot array is given with textual indication of the positions and in (b) with the drawing of the semi-coils (the phases are indicated by the same graphical convention as the cells in FIG. 6), according to the prior art;
[0064] FIG. 8 shows in (a) a standard module of the winding in FIG. 7, and in (b) a standard module of the winding in FIG. 9, according to an example of the prior art (same convention as the preceding figures for the phases);
[0065] FIG. 9 shows a complete winding according to the model (b) in FIG. 8 (same convention as the preceding figures for the phases);
[0066] FIG. 10 shows one of the two pathways (A) of the phase U (same convention as the preceding figures for the phases) and the respective arrangement of the conductors (or semi-coils) so that the electric balance can be ensured between the same, according to an example of the prior art;
[0067] FIG. 11 shows an arrangement of the conductors of all four of the pathways of a phase for a winding with number of slots Z=24, number of pole pairs p=2, number of phases m=3 (same convention as the preceding figures for the phases) and number of pathways a=4, according to an example of the prior art;
[0068] FIG. 12 shows an arrangement of the conductors of a pathway of a phase for a winding with number of slots Z=24, number of pole pairs p=2, number of phases m=3 (same convention as the preceding figures for the phases) and number of pathways a=4, according to the prior art;
[0069] FIG. 13 shows an arrangement of the conductors of all four of the pathways of a winding with number of slots Z=24, number of pole pairs p=2, number of phases m=3 (same convention as the preceding figures for the phases) and number of pathways a=4, according to an example of the prior art;
[0070] FIG. 14 shows an arrangement of the conductors of a pathway of a winding with number of slots Z=24, number of pole pairs p=2, number of phases m=3 (same convention as the preceding figures for the phases) and number of pathways a=4, according to an example of the prior art;
[0071] FIG. 15 shows an arrangement of the conductors of all four of the pathways of a winding with number of slots Z=24, number of pole pairs p=2, number of phases m=3 (same convention as the preceding figures for the phases) and number of pathways a=4, according to an example of the prior art;
[0072] FIG. 16 shows an arrangement of the conductors of a pathway in a winding with number of slots Z=24, number of pole pairs p=2, number of phases m=3 (same convention as the preceding figures for the phases) and number of pathways a=4, according to an aspect of the present description;
[0073] FIG. 17 shows an arrangement of the conductors of all four of the pathways of a phase (the other phases are filled similarly) of a winding with number of slots Z=24, number of pole pairs p=2, number of phases m=3 (same convention as the preceding figures for the phases) and number of pathways a=4, according to an aspect of the present description;
[0074] FIG. 18 shows an arrangement of conductors of the pathways (the other phases are filled similarly) of a winding phase with number of slots Z=72, number of phases m=3 (same convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=12, wherein the general cell occupied by a pathway is identified by a letter (in this case from A to N), indicating the cardinality of the parallel pathways, followed by a number, relative to the N-th conductor (or semi-coil), according to an aspect of the present description;
[0075] FIG. 19 shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding with number of slots Z=72, number of phases m=3 (same convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=6, wherein the general cell occupied by a pathway is identified by a letter with the same convention as the preceding figures (in this case from A to F) according to an aspect of the present description;
[0076] FIG. 20 shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding with number of slots Z=72, number of phases m=3 (same convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=4, wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case from A to D) according to an aspect of the present description;
[0077] FIG. 21 shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding with number of slots Z=72, number of phases m=3 (same convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=2, wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case A and B) according to an aspect of the present description;
[0078] FIG. 22 shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding using stranded hairpins with number of slots Z=72, number of phases m=3 (same convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=6, wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case A-F), where stranded hairpins are used for the layers from 2 to the seventh, according to an aspect of the present description;
[0079] FIG. 23 shows an example of a winding pattern with 4 parallel pathways with number of slots Z=36, number of phases m=3 (same convention as the preceding figures for the phases), number of pole pairs p=2 and number of parallel pathways a=4 wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case A-D), using two types of single-layer hairpins (with pitch k and k+/3) for each end layer, wherein each phase has three slots per magnetic pole; and
[0080] FIG. 24 shows an insertion-side view and a perspective view of a winding according to the pattern in FIG. 23.
[0081] It should be noted here that elements of different embodiments can be combined together to provide further embodiments without restrictions while respecting the technical concept of the solution of the present description, as those skilled in the art will effortlessly understand from the above description.
[0082] Moreover, the present description also makes reference to the prior art for the implementation thereof, as for the detail features, not described, such as elements of minor importance usually used in the prior art in solutions of the same type.
[0083] When an element is introduced, it is always understood that there can be at least one or one or more.
[0084] When a list of elements or features is listed in this description, it is understood that the finding according to the description comprises or alternatively consists of such elements.
[0085] When listing features within the same sentence or bullet list, one or more of the individual features can be included in the description without connection to the other features on the list.
[0086] Hereinafter, the term hairpin and the term basic conductor will be used interchangeably for the conductors used in the present description.
DETAILED DESCRIPTION OF THE INVENTION
Embodiments
[0087] The present description allows eliminating the use of special connections (such as jumpers) in a stator or rotor winding, without modifying the shape of the hairpins forming the general pathway of a phase.
[0088] To show this, note that a hairpin generally consists of two legs configured so that, when inserted into the slots according to the pitch thereof, they are positioned in two different layers and mutually adjacent. The single-layer hairpin instead consists of two legs configured to be positioned in slots of the same layer. FIG. 5 shows this situation with the single-layer hairpin 260 inserted into the slots 350 of the stator 300 having the axis 210.
[0089] Now, according to the present description, the special connections are eliminated, by means of a specific use of single-layer hairpins in the innermost (proximal) layer and in the outermost (distal) layer. Another effect of the present description is the flexibility, in terms of capacity to vary the number of parallel pathways, and therefore the number of semi-coils or conductors per pathway per phase
[00004]
without modifying the shape of the hairpins (except for the use of single-layer ones) and without any repercussions on the process.
[0090] By using the present description and, in particular, by exploiting single-layer hairpins with a determined difference in pitch, between the outer (distal) layer and the inner (proximal) layer, which is equal to at least 2, it is possible to obtain an electrically balanced stator or rotor winding according to the above definition. It is noted that in almost all cases jumpers are not used according to the present description. In fact, the only case in which a jumper is required according to the present description is in the case of a configuration with only one pathway in some particular windings (e.g., if the number of slots per pole per phase is 2).
[0091] An example according to the present description is the winding with four parallel pathways in FIG. 16, where it is possible to note that: [0092] In (distal) layer 1, the conductors A7 and A8 occupy the left and right portion of the standard module, respectively; [0093] In layer 2, the conductors A1 and A6 occupy the left and right portion of the standard module, respectively; [0094] In layer 3, the conductors A2 and A5 occupy the left and right portion of the standard module, respectively; and [0095] In (proximal) layer 4, the conductors A3 and A4 occupy the left and right portion of the standard module, respectively.
[0096] This means that the winding is electrically balanced, where a single-layer hairpin 261 is used on the bottom layer (layer 1), which has a pitch longer than two slots with respect to the single-layer hairpin 262 of the highest layer (layer 4). The same reasoning can be made for all four parallel pathways shown in FIG. 17, where there is still a perfectly electrically balanced winding pattern.
[0097] In this pattern, as in the others shown in the figures, the phases are grouped into magnetic poles (U, V, W), and within the sphere of each magnetic pole, there is provided a number of adjacent slots, at least equal to the number of phases, respectively. However, this is not necessary to respect the concept of the present description.
[0098] According to another example of the present description, shown in FIG. 18, a winding pattern with 8 layers is possible comprising a number of slots Z=72, a number of phases m=3 (wherein the background of the cell is different for different phases, according to the same key in the preceding figures; the same convention is used for the subsequent FIGS. 19-23), a number of pole pairs p=6 (pairs of magnetic poles of the electric machine with opposite polarity) and a number of parallel pathways (of the same phase) a=12. In this exemplary embodiment, the pitch of the innermost single-layer hairpin 262 (layer 1, distal) is 7, while the pitch of the outermost single-layer hairpin (black triangles outside the table) 261 (layer 8, proximal) is 5. In fact, with the same general pattern, the number of pathways can be different, taking the following values, e.g., a=6, a=4, a=2 as in FIGS. 19-21, without varying the shape of the hairpins and without adding/modifying special connections (such as the jumpers, for example), with the sole exception of the configuration with a=1 wherein 1 jumper is required per phase (connection A96-B1 in FIG. 21).
[0099] It should be noted that the configuration with a number of parallel pathways a=12 cannot be achieved according to the method of the prior art described in the aforesaid patent U.S. Pat. No. 10,749,399, i.e., with single-layer hairpins having a difference in pitch of one slot, without compromising the electric balance of the pathways themselves. In fact, with the technique described in such a patent, windings can be balanced which have at most 6 parallel pathways. The present description allows not having predetermined limits to the number of achievable pathways.
[0100] To this end, examples are provided in FIGS. 18-21, where the number of pathways varies, but leaving the difference in slots in the pitches of the single-layer hairpins equal to 2 (7 and 5 for the hairpins of the first and last layer, respectively, starting from the top in the tables).
[0101] Another example is given in FIG. 19, which shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding phase with number of slots Z=72, number of phases m=3 (same graphical convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=6, wherein the general cell occupied by a pathway is identified by a letter with the same convention as the preceding figures (in this case from A to F) according to an aspect of the present description. Also in this case, with 6 pathways, there is a perfect electric balance without using jumpers.
[0102] Another example is given in FIG. 20, which shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding with number of slots Z=72, number of phases m=3 (same graphical convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=4, wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case from A to D) according to an aspect of the present description. Also in this case, with 4 pathways, there is a perfect electric balance without using jumpers.
[0103] A different example is that in FIG. 21, which shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding with number of slots Z=72, number of phases m=3 (same graphical convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=2, wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case A and B) according to an aspect of the present description. Also in this case, with 2 pathways, there is a perfect electric balance without using jumpers.
[0104] A further different example is that in FIG. 22, which shows an arrangement of conductors of the pathways of a phase (the other pathways are filled similarly) of a winding using stranded hairpins with number of slots Z=72, number of phases m=3 (same graphical convention as the preceding figures for the phases), number of pole pairs p=6 and number of parallel pathways a=6, wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case A-F), according to an aspect of the present description, where stranded hairpins are used for the layers from 2 to the seventh. Also in this case, with 6 pathways and a difference in pitch equal to 2 for the single-layer hairpins, there is a perfect electric balance without using jumpers.
[0105] One last example is that in FIG. 23, which shows an example of a winding pattern with 4 parallel pathways with number of slots Z=36, number of phases m=3 (same convention as the preceding figures for the phases), number of pole pairs p=2 and number of parallel pathways a=4 wherein the general cell occupied by a phase is identified by a letter with the same convention as the preceding figures (in this case from A to D), using two types of single-layer hairpins (with pitch k and k+/3) for each end layer. Also in this case, with 4 pathways and a difference in pitch equal to 3 for the single-layer hairpins, there is a perfect electric balance between the pathways without using jumpers. Note that in this case the standard hairpins all have the same pitch (in this particular case pitch 9); the single-layer hairpins have instead pitches 7 and 10 (k+/3), respectively, for both end layers. The single-path configuration is obtained by carrying out the weldings A12-B1, B12-C1 and C12-D1 on the welding side of the winding. On the other hand, the configuration with two parallel paths is obtained by carrying out the weldings A12-B1 and C12-D1.
[0106] As seen above, according to an aspect of the present description, it is generally possible to provide a stator winding which uses single-layer hairpins with a difference in pitch with the other single-layer hairpins present, equal number of slots>1 (counting from the next slot up to and including the arrival one), where the aforesaid stranded hairpins, not present in the aforesaid patent, are also used in the winding.
[0107] FIG. 24 shows an insertion side view and a perspective view of a winding 220 in a drum or stator 230 with axis 210 according to the pattern in FIG. 23, where the hairpins of a general phase have a graphical filling shown in the key. In particular, those in the U phase are also indicated by reference numeral 261, those in the V phase by reference numeral 262, and those in the W phase by reference numeral 263.
[0108] According to an aspect of present the description, it is possible to have several types of single-layer hairpins on one or both end layers (distal and proximal), as can be seen, for example, in FIG. 23 (in an end layer, note that there are two types of single-layer hairpins in terms of pitch) and in FIG. 24, where there are three different types of single-layer hairpins in terms of geometries, and two in terms of pitch.
[0109] According to a different aspect of the present description, in the winding 220 at least one of the single-layer basic conductors 261-263, located on the innermost (proximal) layer or on the outermost (distal) layer of the winding, have the two free ends (twisting side) angled in opposite circumferential directions (so as to prepare the winding for the so-called backtwisting, so that some wires of the crown are bent in the opposite direction to the standard twisting direction, in order to move some standard connections/weldings.
[0110] The above is applicable in windings with at least one distal layer and at least one proximal layer, advantageously in windings also comprising one or more intermediate layers between the distal layer and the proximal layer, in particular at least two intermediate layers.
[0111] Finally, the windings of the present invention cannot contain any jumpers.
[0112] The illustrative patterns shown above can be considered as describing stator or rotor windings beyond the stator or rotor (e.g., after the pre-assembly thereof) or in the stator or rotor (after transferring the winding to the stator or rotor), irrespective of whether all the weldings of the welding side have been carried out. Stranded hairpins, I-pins, nested hairpins, and reverse hairpins are usable as single-layer hairpins or standard hairpins as described above.
Advantages
[0113] With respect to patent U.S. Ser. No. 10/749,399, one solution of the present description comprises the following innovative features: [0114] in the aforesaid patent the difference in pitch between the inner/outer single-layer hairpins and the outer/inner single-layer hairpins is equal to 1; in the present description the difference in pitch between the single hairpins is >1; [0115] in the aforesaid Riedl's patent, the pitch of the hairpins in one of the two single layers (inner or outer, the widest one) must be equal to the pitch of the standard winding hairpins (those belonging to the central crowns of the stator winding); this limitation is not present in the present description; [0116] in the aforesaid patent, it is not possible to have nested single-layer hairpins; the present description can comprise instead nested single-layer hairpins inside a stator winding; [0117] in the aforesaid patent, it is not possible to have stranded hairpins; the present description can comprise the use of stranded hairpins inside the winding; and [0118] with the mentioned Riedl's patent, it is not possible to achieve the maximum number of parallel pathways while ensuring the electric balance between the pathways themselves (e.g., 16 parallel pathways are not possible for the pattern in FIGS. 8 and 9 of the known patent).
[0119] Again with respect to patent U.S. Ser. No. 10/749,399, the present description offers the following advantages: [0120] Greater flexibility, by virtue of the high number of parallel pathways achievable, without compromising the electric balance thereof; and [0121] Simplification of the manufacturing process: in fact, it is possible to obtain a family of stators, maintaining the diameter at the air gap, the number of slots, and the dimensions of the conductor, with a different number of parallel pathways, without the electric balance between the pathways, with minimum impact on the production process.
[0122] In the solution according to the present description, nested single-layer hairpins can be used since the pitch varies by at least+/2 (but also 3, 4, 5, 6 and so on without limitation) with respect to the other underlying or overlying layer.
[0123] Preferred embodiments have been described above and variants of the present description have been suggested, but it is understood that those skilled in the art may make modifications and changes without departing from the related scope of protection, as defined by the appended claims.
