Patterned offset pole rotor

Abstract

The present disclosure provides a "patterned offset pole rotor", a rotor assembly having a rotor, the rotor comprising a plurality of laminations, each lamination defining a plurality of poles, the plurality of poles being arranged such that a pair of angles corresponding to each of the poles and defined between the magnetic axis of the pole and the corresponding interpolar axis adjacent thereto have different values. The values ​​of the pairs of angles define a repeating sequence around the laminations. The angles relative to the axis of rotation of the rotor are equal.

Description

Technical Field

[0001] The present disclosure generally relates to systems and methods for arranging poles in rotor laminations of an electric machine. Background Art

[0002] Extended driving range technologies for electric vehicles, such as battery electric vehicles ("BEVs") and plug-in hybrid electric vehicles ("PHEVs"), are continually improving. However, achieving these increased ranges often requires traction batteries and electric machines to have higher power outputs, and associated thermal management systems to have increased performance compared to previous BEVs and PHEVs.

[0003] Electric machines that include permanent magnets (also known as permanent magnet motors) can have high efficiency, making them potentially suitable for use in traction motors for hybrid and electric vehicles. The design and selection of permanent magnets is important in this type of motor. Rare earth permanent magnets, such as neodymium (Nd) magnets, are often used in traction motors for electric vehicles due to their high flux density and high resistance to demagnetization compared to traditional non-rare earth magnets, such as alnico (an iron alloy including aluminum, nickel, and cobalt) and ferrites. Rare earth permanent magnets can contain large amounts of rare earth elements in some commercial magnets, for example, at least 30 weight percent. Summary of the invention

[0004] A rotor assembly has a rotor, the rotor comprising a plurality of laminations, each lamination defining a plurality of poles, the plurality of poles being arranged such that a pair of angles corresponding to each of the poles and defined between a magnetic axis of the pole and a corresponding interpolar axis adjacent thereto have different values. The values ​​of the pairs of angles define a repeating sequence around the laminations. And, the angles relative to the axis of rotation of the rotor are equal.

[0005] A rotor assembly has a plurality of laminations, each lamination defining a plurality of poles, the plurality of poles being arranged such that a pair of angles corresponding to each of the poles and defined between a magnetic axis of the pole and a corresponding interpolar axis adjacent thereto differ in value. The values ​​of the consecutive odd-numbered pairs define a repeating sequence around the lamination.

[0006] The rotor assembly has a plurality of laminations defining a central opening sized to receive a shaft passing therethrough along an axis of rotation, and defining a plurality of magnet openings sized to receive permanent magnets to form magnetic poles. The magnet openings are arranged so that the values ​​of the respective pairs of angles defined between the magnetic axis corresponding to each of the magnetic poles and the interpolar axis adjacent thereto are different. The values ​​of the respective pairs of angles define a repeating sequence around the laminations. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1is a block diagram showing an electric machine including a plurality of rotor laminations;

[0008] FIG. 2A to FIG. 2B is a block diagram showing rotor axis segments skewed relative to each other;

[0009] Figure 2C to Figure 2D is a block diagram showing an exemplary rotor lamination pole arrangement;

[0010] FIG. 3A to FIG. 3C is a block diagram showing radial skew using distribution of skew angles between poles;

[0011] Figure 4 is a block diagram showing a pole arrangement including a repeating sequence;

[0012] Figure 5 to Figure 6 is a block diagram showing arrangements of repeating sequence poles having different orientations;

[0013] Fig. 7A is a block diagram showing a portion of a rotor lamination having cooling channels; and

[0014] Figure 7B is a block diagram illustrating a cooling channel arrangement including a repeating sequence. DETAILED DESCRIPTION

[0015] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples and that other embodiments may take various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized in order to show the details of a particular component. Therefore, the specific structural details and functional details disclosed herein should not be interpreted as being restrictive, but merely as a representative basis for teaching those skilled in the art to adopt the present invention in different ways. As will be understood by those of ordinary skill in the art, the various features shown and described with reference to any one of the accompanying drawings may be combined with the features shown in one or more other drawings to produce embodiments that are not explicitly shown or described. The combination of features shown provides representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desired for specific applications or implementations.

[0016] Efforts to reduce the magnitude of torque ripple by rotor skew may include offsetting (rotating) one half of the rotor lamination stack relative to the other half. As an example, rotor laminations operating in a 48-slot stator may be arranged relative to each other so that their relative skew angle measures 3.75 degrees. This approach may help reduce the torque ripple component caused by the slotting of the stator. In addition, variations of this approach have been introduced to address second order effects, such as rotor and stator torsional deformations that the skew itself may introduce.

[0017] The rotor can be divided into a predefined number of axial segments k that can be rotated relative to each other by an angle of a predefined size (skew angle). The maximum number of skew angles in a given rotor can be based on the total number k of axial segments in the rotor. The corresponding angles between the magnetic axes of adjacent poles can be the same for all adjacent poles of a given rotor, for example, 45 degrees for an 8-pole rotor design. In addition, each of the angles between the magnetic axis and the interpolar axis determined based on half the value of the previous angle can also be the same as each other, for example, 22.5 degrees for an 8-pole rotor design. In this arrangement, the magnetic axis of each magnet coincides with the rotor d axis and the interpolar axis coincides with the q axis.

[0018] Radial skew can be a skew method achieved within the laminations themselves by offsetting the magnetic axis of the rotor pole relative to one adjacent. The radial skew method can be particularly valuable in applications with integrated starter generator (ISG) motors, where the stack length can be shorter relative to the length of other motor types and axial skew techniques may not produce the desired improved performance. In addition, radial skew can have an equivalent effect to other types of permanent magnet (PM) machines and can result in further reductions in torque pulsations. Unlike axial skew, where the number of skew angles is limited to the number k of axial sections into which the rotor can be divided, the radial skew method applied to a given rotor can have a certain number of degrees of freedom based on the number of poles in the rotor.

[0019] Furthermore, maintaining symmetry of the magnet arrangement with respect to the axis of rotation may be beneficial in achieving desired levels of rotor balance, noise vibration and harshness (NVH), and harmonics in the magnetic flux and induced voltage.

[0020] Figure 1 An exemplary electric machine 100 for an electric vehicle is shown, generally referred to herein as electric machine 100. Electric machine 100 may include a stator 102 and a rotor 104. In some cases, an electric vehicle may include two electric machines 100. One of electric machines 100 may function primarily as a motor, while the other may function primarily as a generator. A motor may be operable to convert electrical power into mechanical power, and a generator may be operable to convert mechanical power into electrical power.

[0021] The stator 102 may define a cavity 106 that is sized to receive the rotor 104 for operation therein. A shaft (not shown) may be operably connected to the rotor 104 to drive its rotation. In some examples, the rotor 104 and the stator 102 may include one or more ferromagnetic laminations 110, 112, respectively. In addition, the laminations 110, 112 may be arranged in a stack 114 and further interlocked or loosened relative to each other.

[0022] The stator laminations 112 may define a plurality of recesses (slots) 116 extending radially from the inner periphery of the stator laminations 112 and sized to receive or retain the coil windings 108. The windings 108 may be disposed within the slots 116 of the stator 102. In an electric motor example, current may be fed to the windings 108 to obtain a rotational force on the rotor 104. In an electric motor generator example, current generated in the windings 108 by the rotation of the rotor 104 may be removed to provide power to vehicle components.

[0023] The rotor laminations 110 may define a plurality of permanent magnet openings (cavities) 118 disposed about the outer periphery of the rotor laminations 110 and each cavity 118 being sized to receive a permanent magnet 120. It should be understood that the magnets 120 and the cavities 118 may include corresponding cross-sectional shapes perpendicular to the axis of rotation 122, such as the rectangular shape shown or alternatively an arcuate shape. The magnets may also be replaced by a plurality of magnets, magnetized in the same direction, such that the plurality of magnets eliminate the same function of the original magnets. The rotor laminations 110 may further define a circular central opening 124 for receiving a drive shaft (not shown), and one or more channels 126 configured to accommodate the flow of cooling oil through the rotor 104.

[0024] The magnetic properties of a given material, such as its electronic configuration and the tendency of the electrons to align their intrinsic magnetic moments (whether spontaneously or with an applied external magnetic field) may be constrained by its microcrystalline structure to point in the same direction. A permanent magnet may be one that exhibits a magnetic flux density B when the magnetizing magnetic field is removed, i.e., r A permanent magnet is a magnet that resists demagnetization while being retained. Given this useful property, permanent magnets have a variety of practical applications, such as, but not limited to, the design of electric motors and / or generators for hybrid electric vehicles, power transformer design, the design and manufacture of magnetic storage devices (e.g., hard disk drives), and the like. A magnetically soft material may be a material that tends to demagnetize relatively quickly after the external magnetic field is removed. In contrast to a magnetically soft material, a permanent magnet may include a magnetically hard material that is capable of retaining magnetic properties (i.e., resisting demagnetization) after being magnetized.

[0025] Rare earth material alloys, such as neodymium-iron-boron (Nd-Fe-B) magnets and samarium-cobalt (Sm-Co) magnets, are examples of magnetically hard materials and can exhibit a number of desirable permanent magnet properties, such as high coercivity H c , high magnetic flux density B and high energy product (BH) 最大). In addition, the permanent magnets defining the composite material or the multiphase combination of one or more materials may exhibit magnetic properties similar to those of rare earth alloys. In one example, the composite permanent magnet may be designed to exhibit magnetic properties superior to those of magnets consisting solely of rare earth alloys. The constituent phases of the composite permanent magnet may be chemically similar, dissimilar, and / or may be separated by different interfaces.

[0026] FIG. 2A to FIG. 2B Exemplary arrangements 200-A and 200-B are shown, respectively, for performing axial skew of a plurality of laminations 110 of a rotor 104. In one example, a strategy for reducing the percentage magnitude of torque ripple by rotor skew may include offsetting (rotating or skewing) one half 114a of a rotor lamination stack 114 relative to the other half 114b. The stack halves 114a, 114b may be rotated relative to each other by a predefined axial rotation (skew) angle 202. For example, the axial skew angle 202 measured in mechanical degrees may be a predefined number N s The stator slots 116 are half the slot pitch of the stator 102, or:

[0027]

[0028] Thus, in an example where the rotor 104 operates in a stator 102 having 48 slots 116, the axial skew angle 202 may be measured as 3.75 degrees. The axial skew may reduce the torque ripple component caused by the slotting of the stator 102. Figure 2B The exemplary arrangement 200-B shown in FIG. 1 may include a plurality of axial segments 206a-206d of the rotor lamination stack 114 that are skewed relative to each other at the same or different axial skew angles 202a-202d. Figure 2B As shown in Figure 2A Compared to the axial deflection 200 -A) shown in FIG. 1 , the axial deflection 200 -B may alleviate or reduce torsional deformation of the rotor 104 and the stator 102 .

[0029] Furthermore, in a rotor lamination stack 114 divided into a predefined number k of axial segments 206, the segments 206 may be rotated relative to each other by an angle measured in mechanical degrees such that:

[0030]

[0031] The maximum relative rotation between any two axial sections 206 of a given rotor 104 may be determined using the following formula:

[0032]

[0033] Figure 2CAn exemplary arrangement 200-C of a plurality of poles 208 of a rotor lamination 110 is shown. The d-axis 220 may refer to an axis of symmetry of the rotor magnetic flux, and the q-axis 222 may refer to an axis located midway between a pair of magnets 120. In one example, the d-axis 220a may be aligned with the direction of the north pole magnetic flux, and the –d-axis 220b may be aligned with the direction of the south pole magnetic flux. Additionally or alternatively, the magnetic axis 212 of a given magnet 120 may be located at the center of the magnetic flux along that magnet 120, and the interpolar axis 210 may be located at a midpoint along between each pair of adjacent magnets 120. Figure 2C As shown, the magnetic axis 212 of each magnet 120 may correspond to (or be located along) a d-axis (or −d-axis) 220 of the machine 100, and the interpolar axis 210 may correspond to (or be located along) a q-axis (or −q-axis) 222 of the machine 100. In some other examples, such as at least with reference to Figure 2D As mentioned, the respective magnetic axis 212 of each of the magnets 120 may or may not lie along one of the d-axis 220 a and the −d-axis 220 b of the machine 100 .

[0034] Thus, each pole 208 may be a portion of the laminations 110 disposed between adjacent inter-pole axes 210, which in turn are substantially disposed between a pair of adjacent lamination cavities 118. The distance between a given pair of adjacent inter-pole axes 210 may indicate the size of the pole 208 disposed therebetween, and may be generally represented by the angle Each pole 208 may also include a corresponding magnetic axis 212 about the center of the permanent magnet 120 disposed within the cavity 118. Furthermore, if the rotor 104 design includes more than one magnet 120 per pole 208, the magnetic axis 212 is defined by the total flux generated by all of the magnets 120 residing in a given pole 208.

[0035] Figure 2C The poles 208 of the rotor laminations 110 shown in FIG. 1 may be symmetrically distributed relative to each other. Thus, the first angle α 214 between the respective magnetic axes 212 of a pair of adjacent poles 208 may be the same for all pairs of adjacent poles 208. In addition, a given interpolar axis 210 and a pair of magnetic axes 212 adjacent to the interpolar axis 210 may define a second angle β 216 and a third angle γ 218 therebetween, respectively. The axial skew may cause the second angle 216 and the third angle 218 to be the same as each other, for example, such that Furthermore, the sum of the second angle 216 and the third angle 218 may correspond to the first angle α 214 and the angle The value of each of .

[0036] Figure 2DAn exemplary arrangement 200-D is shown in which the poles 208 are radially skewed relative to the d-axis 220 and the q-axis 222 of the rotor laminations 110. The radial skew may include offsetting the magnetic axis 212 of a given rotor pole 208 relative to the d-axis 220 of the rotor 104. Unlike axial skew, in which the number of axial skew angles 202 may be based on the number k of axial segments 206 into which the rotor 104 may be divided, the radial skew applied to a given rotor 104 may include a number n of degrees of freedom based on the number N of rotor poles 208. P , or n = N P -1.

[0037] Furthermore, when radial skew is used, the angles α 214 between the respective magnetic axes 212 of each pair of adjacent poles 208 may be dependent on one another, in that a positive radial skew applied to a first pair of adjacent poles 208 causes a negative radial skew having the same value to be applied to a second pair of adjacent poles 208 disposed adjacent to the first pair of poles. In one example, the respective values ​​of the angles α 214 between two pairs of adjacent poles 208 may be determined using the following formula:

[0038]

[0039] and

[0040]

[0041] Thus, in an exemplary 8-pole 48-slot machine 100 with a predefined skew angle of 3.50°, the mechanical angle α 偏斜_正 and α 偏斜_负 They can be 48.50°, 41.50°, and so on.

[0042] Figure 3A An exemplary arrangement 300-A of radially skewed rotor poles 208 of laminations 110 is shown. Arrangement 300-A may include poles 208a-h that are radially skewed by a predefined skew angle relative to a d-axis 220 of rotor 104 such that the values ​​of the skew angle are distributed among several stages 208a-h.

[0043] More specifically, the value of the positive skew angle may be evenly divided among several pairs of adjacent poles 208a-h, and the value of the negative skew angle may be applied to a single pair of adjacent poles 208a-h. In one example, the angles 214a-214g between the corresponding magnetic axes 212 of each pair of adjacent poles 208a-h having the same value α1 may be determined using the following formula:

[0044]

[0045] The amount Defines the positive skew angle (hereinafter referred to as offset) applied to NP −1 portion of each of the pairs of adjacent poles 208a-h. Additionally, the angle 214h between the respective magnetic axes 212 of adjacent poles 208a and 208h having a value of α2 may reflect that the magnitude of the negative skew angle is equal to the magnitude of the positive skew angle determined using the following formula:

[0046]

[0047] In one example, if Figure 3B As shown, the angle α1 214a between the first pole magnetic axis 212a and the second pole magnetic axis 212b may include an angle β2 216b and an angle γ1 218a. The angle β2 216b may be defined by the interpole axis 210 between the poles 208a, 208b and the magnetic axis 212 of the second pole 208b. The angle γ1 218a may be defined by the interpole axis 210 between the poles 208a, 208b and the magnetic axis 212a of the first pole 208a. As another example, the angle α1 214b between the second pole 208b and the third pole 208c may include an angle β3 216c and an angle γ2 218b, each of which is defined in a manner similar to the angles 216a, 218a, respectively. As another example, angles α1 214c, 214d, 214e, 214f, 214g, and α2 214h may each include respective angles β216 and γ218 defined in a manner similar to angles β3, β2, γ1, γ2 216c, 216b, 218a, 218b that comprise angles 214a, 214b.

[0048] Note that the poles 208a-h of arrangement 300-A have been radially skewed, e.g., according to equations (6) and (7), thereby affecting one or more distances between pairs of adjacent poles 208, and the sum of angles β 216 and γ 218 may correspond to values ​​corresponding to angles α1 and α2 as follows:

[0049] α1=β2+γ1=β3+γ2=β4+γ3=...=β8+γ7, (8)

[0050] and

[0051] α2=β1+γ8. (9)

[0052] At least in reference Figure 2CIn the depicted symmetric pole 208 distribution, the angles β 216, γ 218 are equal to each other, and the relative skew angles β1 216a, β2 216b, β3 216c, β4 216d, β5 216e, β6 216f, and β7 216g may have values ​​different from those of each other and / or different from β8 216h. The angles γ1 218a, γ2 218b, γ3 218c, γ4 218d, γ5 218e, γ6 218f, and γ7 218g may have values ​​different from those of each other and / or different from γ8 218h.

[0053] Figure 3C Shown for FIG. 3A to FIG. 3B 300-C of an exemplary arrangement of poles 208a-h reordered relative to each other. Arrangement 300-C includes pole 208c replacing pole 208h (or occupying the previous sequence position of 208h), pole 208d replacing pole 208c, pole 208e replacing pole 208g, pole 208f replacing pole 208d, pole 208g replacing pole 208f, and pole 208h replacing pole 208e. Thus, FIG. 3A to FIG. 3B The original sequence of poles 208a-h, as viewed, for example, in a counterclockwise direction, is ABCDEFGH, and Figure 3C The recombined sequence, as seen in the same orientation, is ABDFHGEC.

[0054] The respective angles β 216, γ 218 of each of the poles 208a-h as measured between the magnetic axis 212 of a given pole 208 and the inter-pole axis 210 defining the outer boundary of the pole 208 may be Figure 3C In some cases, the reorganization with a different sequence (such as sequence 300-C) remains the same. FIG. 3A to FIG. 3B The poles 208a-h described in the above description may provide torque ripple magnitudes similar to those of the original pole sequences 300-A and / or 300-B. Figure 3C The described reordering results in an exemplary pole 208 pattern of ABDFHGEC, but different resulting pole patterns are also contemplated. In addition, other ordering arrangements are also contemplated (such as, but not limited to, reordering such that the angles β 216, γ 218 of each of the poles 208a-h define a random value within a predefined range).

[0055] Furthermore, maintaining full or partial symmetry in the arrangement of the magnets 120 relative to the axis of rotation 122 may be beneficial in increasing rotor balance and / or reducing noise vibration and harshness (NVH) and harmonics in the magnetic flux and induced voltage. Figure 4An exemplary arrangement 400 of a plurality of poles 208 within rotor laminations 110 is shown. In one example, arrangement (or sequence) 400 of poles 208 may be a predetermined pattern of poles 208 that includes a subset (hereinafter subset) 402 of the sequence that is repeated a predefined number of times T throughout arrangement 400.

[0056] Subset 402 may include a predefined number M of poles 208 , where number M is less than a total number N of poles 208 within rotor laminations 110 . P Furthermore, the number M may be such that the subset 402 may be repeated at least once within the arrangement 400 , ie, the number M of poles 208 in the subset is the total number N of poles 208 in the rotor laminations 110 P Half of. A subset 402 of a stack 110 having eight poles 208 may include four poles 208, for example, poles 208b, 208d, 208f, and 208h, ordered in a pattern BDFH. Subset 402 repeats immediately after the last pole 208 of subset 402 (for example, immediately after pole 208h), such that the resulting pole pattern of arrangement 400 is BDFHBDFH. In another example, the four poles 208 of subset 402 may be poles 208a, 208c, 208e, and 208g, and the resulting pole pattern of arrangement 400 may be ACEGACEG.

[0057] The arrangement 400 may cause one or more angles β 216, γ 218 to be substantially symmetrical relative to the rotation axis 122 of the machine 100. In some examples, each of the angles β 216, γ 218 corresponding to the poles 208 of the subset 402 may be symmetrical relative to the rotation axis 122, such that an angle γ 8 218 h defined by the magnetic axis 212 h of the pole 208 h and the inter-pole axis 210 of adjacent poles 208 h, 208 b may be symmetrical relative to the rotation axis 122 about the angle γ 8 218 h, and so on.

[0058] Figure 5 An exemplary arrangement 500 of the plurality of poles 208 within the rotor laminations 110 is shown. The arrangement 500 may represent a symmetrical arrangement of Figure 3C 300-C of the reordered arrangement ABDFHGEC shown in FIG. In one example, the arrangement 500 may include a subset 502 of the sequence 300-C that is BDHF. The subset 502 of BDHF may be further repeated a predefined number of times T in the entire pole 208 sequence of the arrangement 500, so that the resulting pole 208 sequence of the arrangement 500 may be BDHFBDHF.

[0059] The arrangement 500 may cause one or more angles β 216, γ 218 to be substantially symmetrical relative to the rotation axis 122 of the machine 100. In some examples, each of the angles β 216, γ 218 corresponding to the poles 208 of the subset 502 may be symmetrical relative to the rotation axis 122, such that the angle γ 6 218 f defined by the magnetic axis 212 f of the pole 208 f and the inter-pole axis 210 of the adjacent poles 208 f, 208 h may be symmetrical relative to the rotation axis 122 about the angle γ 6 218 f, and so on.

[0060] Additionally or alternatively, the reordered arrangement 300-C may be further arranged in a repeating sequence such that the subset 502 is ACGE and the resulting arrangement 500 may be ACGEACGE. Figures 4 to 5 1 is shown as including a pair of magnets 120 arranged in a V-shape, with the repeating sequence arrangement applied to a flat V-shaped multi-layer magnet, but other magnet layouts are also contemplated.

[0061] Although FIG. 3A to FIG. 3B The rotor shown in is an 8-pole rotor (i.e., characterized by 8 magnets or groups of magnets having alternating polarities), but it is also contemplated that the repeating sequence arrangement may be applied to rotors defining more or fewer poles. For example, a repeating sequence arrangement applied to a 16-pole rotor may include an ordered subset of 4 poles repeated a predefined number of times throughout the sequence length. Additionally or alternatively, the repeating sequence arrangement may include an ordered subset of 8 poles repeated a predefined number of times throughout the sequence length (e.g., ABDFHGECABDFHGEC). Other combinations of pole subset patterns and / or the number of poles 208 in a given pattern are also contemplated.

[0062] To further improve the harmonic and noise performance of the electric machine 100, the plurality of axial segments 206 of the rotor 104 (where each segment 206 includes a plurality of laminations 110) may be rotated relative to each other by an axial skew angle 202 (which is an angle or a multiple of ) or a distance between the interpolar axes 210 defining at least one of the poles 208:

[0063]

[0064] where τ is the multiplier variable.

[0065] Additionally or alternatively, the initial orientation of the poles 208 within each of the axial segments 206 may be different before being rotated by the axial skew angle 202. For example, one of the axial segments 206 may be rotated relative to the other by an angle corresponding to half the number of poles 208 in the subset. Figure 5 The arrangement of 500 up to 90 degrees can result in Figure 6, whereby subset 502 of BDHF becomes subset 602 of HFBD. In a manner similar to subset 502, the sequence HFBD of subset 602 may be repeated a predefined number of times T in the entire sequence of poles 208 of arrangement 600, such that the resulting sequence of poles 208 of arrangement 600 may be HFBDHFBD.

[0066] Furthermore, since rotating the arrangement 500 to generate the arrangement 600 does not change the values ​​of the angles β 216 , γ 218 of the poles 208 , the symmetry of the angles β 216 , γ 218 of the subset 502 with respect to the rotation axis 122 can be preserved in the subset 602 . Figure 2B ) can be placed on top of or otherwise combined with a second axial segment 206b including laminations 110 oriented in arrangement 602 such that pole 208d of first segment 206a can be aligned with pole 208f of second segment 206b, pole 208b of first segment 206a can be aligned with pole 208h of second segment 206b, etc. Other combinations, orientations, arrangements, and placements of segments 206 relative to each other are also contemplated.

[0067] Additionally or alternatively, the rotated second axial segment 206b may be further rotated by an additional angle ψ (not shown) prior to combining with the first axial segment 206a, so that the combined axial segments 206a, 206b having the same polar pattern have different angles β 216, γ 218 when aligned with each other. In some cases, the magnitude of the angle ψ may be smaller (e.g., one-tenth) or less than the magnitude of the rotation angle (i.e., an angle of half the number of polar poles 208 in the subset).

[0068] Further, the first axial segment 206a and the second axial segment 206b can have different pole arrangements from each other. Likewise, a given axial segment 206 can include multiple laminations 110 that have different pole patterns from each other. In one example, laminations 110 having a first pole arrangement of BDHFBDHF can be combined with laminations 110 having a second pole arrangement of ACGEACGE, and so on. Other arrangements, sequences, and combinations, as well as their relative orientations, are also contemplated.

[0069] Although Figures 4 to 6Each of the subsets 402, 502, 602 described in includes an even number of poles 208, but subsets including an odd number of poles 208 are also contemplated. In addition, the number of poles 208 in a given subset may determine whether the final sequence renders one or more angles β216, γ218 of the poles 208 symmetrical with respect to the rotation axis 122.

[0070] Fig. 7A An exemplary layout 700 -A is shown for a plurality of openings for a rotor lamination 110 . In one example, the laminations 110 of the layout 700 -A may include a plurality of cooling channels 126 configured to direct a cooling substance throughout one or more portions of the machine 100 . Figure 7B An exemplary repeating sequence arrangement 700-B of cooling channels 126 for a lamination stack 110 is shown. As an example, for a plurality of poles 208 arranged in a repeating sequence pattern, e.g., such that the magnitude of the angle between the magnetic axis 212 of a given pole 208 and the interpole axis 210 of that pole 208 and an adjacent pole 208 is equal to the magnitude of the angle defined by the same axes 210, 212 extending across the central opening 124 of the lamination stack 110, the cooling channels 126 may be arranged such that the central axis 710 of the cooling channels 126 is disposed at an intermediate position, i.e., As another example, the central axis 710 of each of the cooling passages 126 may be offset from the inter-pole axis 210 between a given pair of adjacent poles 208 by a predefined angle λ706 such that the angle ω1 between the axis 710 of a given passage 126 and one of the adjacent magnetic axes 212 of the pole 208 is equal to the angle ω1 defined by the same axes 710, 212 extending through the central opening 124.

[0071] The words used in the specification are words for description rather than limitation, and it should be understood that various changes can be made without departing from the spirit and scope of the present invention. As previously mentioned, the features of various embodiments can be combined to form other embodiments of the present invention that may not be clearly described or shown. Although various embodiments can be described as providing advantages or better relative to other embodiments or prior art implementations with respect to one or more desired characteristics, it is recognized by those of ordinary skill in the art that one or more features or characteristics can be compromised to achieve the desired overall system properties, depending on the specific application and implementation. These properties may include but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. In this way, embodiments described as being less desirable than other embodiments or prior art implementations with respect to one or more characteristics are outside the scope of the disclosure and may be desirable for specific applications.

Claims

1. A rotor assembly, comprising: A rotor comprising a plurality of laminations, each lamination defining a plurality of poles, the plurality of poles being arranged such that a pair of angles corresponding to each of the poles and defined between a magnetic axis of the pole and a corresponding interpolar axis adjacent thereto have different values, the values ​​of the respective pairs of angles defining a repeating sequence around the laminations and being equal in angle relative to the axis of rotation of the rotor, wherein the laminations form a plurality of axial segments radially deflected relative to each other by a predefined axial deflection angle, wherein the respective magnitudes of the deflection angles are different between two consecutive pairs of adjacent segments.

2. The rotor assembly of claim 1, wherein each of said magnetic axes is located at a center of magnetic flux along a corresponding one of said poles, and each of said interpolar axes is located between an adjacent pair of said poles.

3. The rotor assembly of claim 1 wherein the poles are further arranged such that at least one of the magnetic axes is offset from a d-axis of the rotor located along a center of total magnetic flux and each of the interpolar axes is located along one of the q-axes of the rotor.

4. A rotor assembly comprising: A plurality of laminations, each lamination defining a plurality of poles, the plurality of poles being arranged such that a pair of angles corresponding to each of the poles and defined between a magnetic axis of the pole and a corresponding interpolar axis adjacent thereto have different values, and consecutive odd-numbered pairs of angles have different values ​​defining a repeating sequence around the laminations, wherein the laminations form a plurality of axial segments radially deflected relative to each other by a predefined axial deflection angle, wherein the respective magnitudes of the deflection angles between two consecutive pairs of adjacent segments are different.

5. The rotor assembly of claim 4, wherein each of said magnetic axes is located at a center of magnetic flux along a corresponding one of said poles, and each of said interpolar axes is located between an adjacent pair of said poles.

6. The rotor assembly of claim 4, wherein the poles are further arranged such that at least one of the magnetic axes is offset from a d-axis of the rotor assembly located along a center of total magnetic flux, and each of the interpolar axes is located along one of the q-axes of the rotor.

7. A rotor assembly comprising: A plurality of laminations defining a central opening sized to receive a shaft passing therethrough along an axis of rotation, and defining a plurality of magnet openings sized to receive permanent magnets to form magnetic poles, wherein the magnet openings are arranged such that respective pairs of angles defined between a magnetic axis corresponding to each of the poles and an interpolar axis adjacent thereto have different values, and said values ​​of said respective pairs of angles define a repeating sequence around the laminations, wherein the laminations form a plurality of axial segments radially deflected relative to each other by a predefined axial deflection angle, wherein respective magnitudes of said deflection angles between two consecutive pairs of adjacent segments are different.

8. The rotor assembly of claim 7, wherein each of said magnetic axes is located at a center of magnetic flux along a corresponding one of said poles, and each of said interpolar axes is located between an adjacent pair of said poles.

9. The rotor assembly of claim 7, wherein the openings are further arranged such that at least one of the magnetic axes is offset from a d-axis of the rotor assembly located along a center of total magnetic flux, and each of the interpolar axes is located along one of the q-axes of the rotor.

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