Axially asymmetric configuration for a machine with internal permanent magnets
Patent Information
- Application Number
- DE102016105078
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2015-07-01
- Filing Date
- 2016-03-18
- Publication Date
- 2024-12-19
- Estimated Expiration
- 2036-03-18
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
CROSS REFERENCE TO RELATED APPLICATIONSThis application claims priority to U.S. Provisional Application No. 62 / 135,909, filed Mar. 20, 2015, which is hereby incorporated by reference in its entirety.TECHNICAL FIELDThe present invention relates generally to an internal permanent magnet machine and, more particularly, to the configuration of rotor slots in the internal permanent magnet machine.BACKGROUNDAn internal permanent magnet machine generally includes a rotor having a plurality of magnets of alternating polarity recessed within the rotor. The rotor is rotatable within a stator, which generally includes a plurality of windings. Permanent magnet machines can generate radial forces on the stator teeth, which leads to unwanted vibrations and noise.The publication DE 10 2004 036 691 A1 discloses a machine with internal permanent magnets, the rotor of which is constructed from a plurality of axially stacked segments which are rotated relative to one another about an axis of rotation in order to achieve a pole bevel.SUMMARYAn internal permanent magnet machine includes a rotor having a central axis and a plurality of axial segments. The axial segments include a first axial segment and a second axial segment positioned adjacent to each other in an axial direction. Each of the axially spaced segments includes at least one pole defining a respective angular configuration characterized by respective first, second and third angles. The first axial segment defines a first set of angular configurations and the second axial segment defines a second set of angular configurations. The rotor is configured to have an axially asymmetric configuration such that the first set of angular configurations is different than the second set of angular configurations.The at least one pole includes a pole axis extending centrally through the at least one pole from the central axis and a first pair of slots configured to be symmetrical to the pole axis and disposed in a radially inner first layer. The first angle is defined between the pole axis and a first centerline of a groove of the first pair of grooves. A second pair of slots is configured to be symmetrical about the pole axis and disposed in a radially outer second layer. The second angle is defined between the pole axis and a second centerline of a groove of the second pair of grooves. A pair of outer grooves are configured to be symmetrical to the pole axis and formed proximate an outer surface of the rotor. The third angle is defined between the pole axis and a third centerline of one of the pair of outer slots.In a first embodiment, the first axial segment includes a first pole (A) directly adjacent to a second pole (B) and the second axial segment includes a third pole (C) directly adjacent to a fourth pole (D). Each of the first, second, third, and fourth poles (A, B, C, D) defines respective first, second, third, and fourth angle configurations [(A 1, A 2, A 3), ( B 1, B 2, B 3), ( C 1, C 2, C 3), ( D 1, D2, D3)] represented by respective first, second, and third angles. Adjacent segments of the plurality of axial segments may be rotated around the axial direction alternately. The first angular configuration (A 1, A 2, A 3) and the fourth angular configuration (D 1, D 2, D 3) are the same. The second angular configuration (B 1, B 2, B 3) and the third angular configuration (C 1, C 2, C 3) are the same. The first axial segment has a pole-to-pole asymmetry such that the first angular configuration (A 1, A 2, A 3) is different from the second angular configuration (B 1, B 2, B 3). The second axial segment has a pole-to-pole asymmetry such that the third angular configuration (C 1, C 2, C 3) is different from the fourth angular configuration (D 1, D 2, D 3). It is the combination of these features that enables a reduction in both torque ripple and radial force due to the pole-pass order radial force].The first angular configuration (A 1, A 2, A 3) may be different from the second angular configuration (B 1, B 2, B 3) when a difference between the respective first and / or second and / or third angles in the first angular configuration relative to the second angular configuration is at or above a threshold. The first angular configuration (A 1, A 2, A 3) may be different from the second angular configuration (B 1, B 2, B 3) when a respective difference between at least two of the respective first, second and third angles in the first angular configuration relative to the second angular configuration is at or above a threshold. The first angular configuration (A 1, A 2, A 3) may be different from the second angular configuration (B 1, B 2, B 3) when a respective difference between both the respective first and second and third angles in the first angular configuration relative to the second angular configuration is at or above a threshold.In a second embodiment, the first axial segment includes a first pole (E) directly adjacent to a second pole (F) and the second axial segment includes a third pole (G) directly adjacent to a fourth pole (H). Each of the first, second, third, and fourth poles (E, F, G, H) defines respective first, second, third, and fourth angle configurations [(E 1, E 2, E 3), ( F 1, F 2, F 3), ( G 1, G 2, G 3), ( H 1, H2, H3)] represented by respective first, second, and third angles. The first axial segment has a pole-to-pole symmetry such that the first angular configuration (E 1, E 2, E 3) and the second angular configuration (F 1, F 2, F 3) are the same. The second axial segment has pole-to-pole symmetry such that the third angular configuration (G 1, G 2, G 3) and the fourth angular configuration (H 1, H 2, H 3) are the same. The first and second axial rotor segments define different sets of angular configurations such that: the first angular configuration (E 1, E 2, E 3) is different from both the third angular configuration (G 1, G 2, G 3) and the fourth angular configuration (H 1, H 2, H 3); and that the second angular configuration (F 1, F 2, F 3) is different from both the third angular configuration (G 1, G 2, G 3) and the fourth angular configuration (H 1, H 2, H 3). It is the combination of these features that enables a reduction in both torque ripple and radial force due to pole passing order.The first angular configuration (E 1, E 2, E 3) may be different from the third angular configuration (G 1, G 2, G 3) if a difference between the respective first and / or second and / or third angles in the first angular configuration relative to the third angular configuration is at or above a threshold. The first angular configuration (E 1, E 2, E 3) may be different from the third angular configuration (G 1, G 2, G 3) when a respective difference between at least two of the respective first, second and third angles in the first angular configuration relative to the third angular configuration is at or above a threshold. The first angular configuration (E 1, E 2, E 3) may be different from the third angular configuration (G 1, G 2, G 3) when a respective difference between each of the respective first, second, and third angles in the first angular configuration relative to the third angular configuration is at or above a threshold.The above features and advantages and other features and advantages of the present disclosure will be readily apparent from the following detailed description of the best modes for carrying out the disclosure when read in connection with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic fragmentary perspective view of an internal permanent magnet machine showing a rotor having a plurality of axially spaced segments including first and second axial segments; FIG. 2 is a schematic cross-sectional view of a portion of FIG. 1 ; FIG. 3 is a schematic fragmentary cross-sectional view of the first axial segment in accordance with a first embodiment; FIG. 4 is a schematic fragmentary cross-sectional view of the second axial segment in accordance with the first embodiment; FIG. 5 is a schematic fragmentary cross-sectional view of the first axial segment in accordance with a second embodiment; and FIG. 6 is a schematic fragmentary cross-sectional view of a portion of the second axial segment in accordance with the second embodiment.DETAILED DESCRIPTIONReferring to the Figures, wherein like reference numerals designate like or similar components throughout the several views, FIG. 1 is a schematic perspective view of an interior permanent magnet machine 10 having a rotor 12 disposed about a central axis 14. The rotor 12 is rotatable within a generally toroidal stator (not shown). Figure 2 is a schematic cross-sectional view of a portion of Figure 1. Referring to Figures 1-2, the rotor 12 is formed with a plurality of grooves 16 extending into the rotor 12 and defining a three-dimensional volume having any suitable shape. All or a part of the grooves 16 may / may be filled with permanent magnets 17. The grooves 16 may be disposed in a radially inner first layer 18 and in a radially outer second layer 20.Referring to FIG. 1, the rotor 12 includes a plurality of poles 22, all of which have respective pole axes 24 extending from the central axis 14 and midway through the respective poles. The rotor 12 may be formed with any number of poles or slots. In one example, the rotor 12 is formed with 8 poles and 72 stator slots. In another example, the rotor 12 is formed with 10 poles.Referring to FIG. 1, the rotor 12 includes a plurality of axial segments 26 oriented axially or spaced apart from one another about the central axis 14. The axial direction X is parallel to the central axis 14. For illustrative purposes, the rotor 12 is shown having first, second, third, and fourth axial segments 30, 32, 34, and 36; however, any number of axial segments may be used.As shown in FIG. 1, the axial segments 30, 32, 34, and 36 are configured in the shape of a circular ring or ring having an inner surface 38 and an outer surface 40. The second axial segment 32 is directly adjacent to the first axial segment 30 on one side and to the third axial segment 34 on the other side in the axial direction. The third axial segment 34 is directly adjacent to the second axial segment 32 on one side and to the fourth axial segment 36 on the other side in the axial direction.Referring to FIG. 2, a representative pole 42 is shown. Each pole 42 includes a first pair of slots 44 symmetrical to the pole axis 46 and disposed in the radially inner first layer 18. Each groove of the first pair of grooves 44 defines a respective centerline. Referring to FIG. 2, a first angle 50 is defined between a first centerline 48 passing through the center of a slot of the first pair of slots 44 (any of the slots because they are symmetrical to the pole axis 46) and the pole axis 46. Each pole 42 includes a second pair of slots 52 symmetrical to the pole axis 46 and disposed in the radially outer second layer 20. Each groove of the second pair of grooves 52 defines a respective centerline. Referring to FIG. 2, a second angle 56 is defined between a second centerline 54 through the center of a slot of the second pair of slots 52 (any of the slots because they are symmetrical to the pole axis 46) and the pole axis 46.Each pole 42 includes a pair of outer slots 58 formed proximate the outer surface of the rotor 12. A third centerline 60, extending from the central axis 14, passes through the center of one of the pair of outer slots 58 (any of the slots because they are symmetrical to the pole axis 46). A third angle 62 is defined between the third centerline 60 and the pole axis 46. The set (50, 56, 62) of the first, second, and third angles 50, 56, 62 describes or defines the slot configuration or "angular configuration" of each pole 42.The rotor 12 is configured to have an asymmetric configuration in the axial direction such that directly adjacent axial segments, such as the first and second axial segments 30, 32, define different sets of angular configurations. The axially asymmetric configurations will be described with reference to two embodiments: a first embodiment shown in FIGS. 3-4 and a second embodiment shown in FIGS. 5-6. The first axial segment 30 (in the second embodiment 130) defines a first set of angular configurations 31 (131) and the second axial segment 32 (132) defines a second set of angular configurations 33 (133). The rotor 12 is configured to have an asymmetric configuration in the axial direction, such that the first set of angle configurations 31( 131) is different from the second set of angle configurations 33( 133), as described below.The axially asymmetric configurations help reduce radial forces generated by the machine 10 and transmitted through the stator teeth (not shown), resulting in undesirable noise in the transmission housing (not shown). The noise frequencies may be characterized by pole-passing orders and non-pole-pass orders [Engl.: poles and non-pole-pass orders]. The pole passing orders are the number of poles in the rotor 12 and their integer multiples. For example, an 8-pole machine has pole crossing orders of 8, 16, 24, 32, 40, etc. The tooth forces can be calculated, for example, using the stress tensor method [Stress Tensor Method] from Maxwell. After the tooth forces are calculated, different orders may be calculated after performing a Fast Fourier Transform (FFT). FFT extracts the magnitude and phases of each of the orders.First EmbodimentIn the first embodiment, referring to FIG. 3, the first axial segment 30 includes a first pole 66(A) directly adjacent to a second pole 68(B). Each of the first, second, third and fourth poles 66, 68, 70, 72 defines respective first, second, third and fourth pole axes 67, 69, 71, 73 extending from the central axis 14 and midway through the respective poles. Referring to FIG. 4, the second axial segment 32 includes a third pole 70 (C) directly adjacent to a fourth pole 72 (D). Each of the first, second, third, and fourth poles 66, 68, 70, 72 defines respective first, second, third, and fourth angle configurations 74, 76, 78 80 [(A 1, A 2, A 3), ( B 1, B 2, B 3), ( C 1, C 2, C 3), ( D 1, D2, D3)] represented by the respective first, second, and third angles 50, 56, 62 described with reference to FIG. 2. The pattern shown by the first and second poles 66(A), 68(B) may be repeated for the remainder (not shown) of the first axial segment 30. The pattern shown by the third and fourth poles 70(C), 72(D) may be repeated for the remainder (not shown) of the second axial segment 32. Although a pattern having two poles is shown in this embodiment, a pattern having 3 poles or having 4 poles may also be used. The first axial segment 30 defines the first set of angular configurations 31 and the second axial segment 32 defines the second set of angular configurations 33. the rotor 12 is configured to have an asymmetric configuration in the axial direction such that the first set of angular configurations 31 is different from the second set of angular configurations 33, as described below. The first set of angle configurations 31 may be different from the second set of angle configurations 33 if any of the angle configurations in the first set differ from the second set.In assembling the stack in the first embodiment, the plurality of axial segments 26 may be alternately tilted in the axial direction to cancel the forces in the non-pole passing order, e.g., the 68th order. When axially adjacent segments are alternately tilted (such as by tilting the second and fourth axial segments 32, 36, but not the first and third axial segments 30, 34), the non-pole pass orders are decreased or eliminated while pole pass orders are not affected. Consequently, the first angular configuration 74 (A 1, A 2, A 3) and the fourth angular configuration 80 (D 1, D 2, D 3) are the same, i.e., the respective angles are the same (A 1= D 1, A 2= D 2, A3=D3). Similarly, the second angular configuration 76 (B 1, B 2, B 3) and the third angular configuration 78 (C 1, C 2, C 3) are the same. Referring to FIG. 1, the first pole A is directly adjacent to the third pole C in the axial direction X. As shown in FIG. 1, the second pole B is directly adjacent to the fourth pole D in the axial direction X.Moreover, in the first embodiment, adjacent poles in each of the plurality of axial segments 26 may be placed at asymmetric angles, i.e., the rotor magnets 17 may be placed asymmetrically between north and south poles. Referring to FIG. 3, the first axial segment 30 has a pole-to-pole asymmetry such that the first angular configuration 74 (A 1, A 2, A 3) is different from the second angular configuration 76 (B 1, B 2, B 3). Referring to FIG. 4, the second axial segment 32 has a pole-to-pole asymmetry such that the third angular configuration 78 (C 1, C 2, C 3) is different from the fourth angular configuration 80 (D 1, D 2, D 3). Different angles of the magnets between north and south poles or pole-to-pole asymmetry serves to reduce torque ripple and radial force due to pole passing order, especially that with a 72th order torque ripple for a geometry with a rotor 12 with 8 poles and 72 stator slots. Also, the 68th order of the non-pole pass order is for a rotor 12 having a combination of 8 poles and 72 stator slots.The angle configurations may be referred to as "different" if the difference (|A i- B i|) at at least one of the three angles relative to the same angle in a different angle configuration (i.e., the angle A 1 is compared to the angle B 1 but the angle A 1 is not compared to the angle B 2 ) is at or above a threshold. In one example, the threshold is 1% or more. Thus, the first angular configuration 74 (A 1, A 2, A 3) is different from the second angular configuration 76 (B 1, B 2, B 3), when the difference between the angles A 3 and B 3 is about 1% or more. In one example, the first angular configuration is 74 (A 1, A 2, A 3) in degrees (52, 50.5, 0.2) and the second angular configuration is 76 (B 1, B 2, B 3) in degrees (52, 50.5, 3.75). The threshold may be defined differently for each application.The angle configurations may be referred to as "different" if the difference at at least two of the three angles relative to the same angle in another angle configuration is at or above the threshold. Thus, the first angular configuration 74 (A 1, A 2, A 3) is different from the second angular configuration 76 (B 1, B 2, B 3), when the respective differences between the angles A 1 and B 1 and the angles A 3 and B 3 are about 1% or more. In one example, the first angular configuration is 74 (A 1, A 2, A 3) (52, 48,7, 0,2) and the second angular configuration is 76 (B 1, B 2, B 3) (55, 48.7, 3.75), each in degrees. The angle configurations may be referred to as "different" if the respective differences at each of the three angles relative to the same angle in a different angle configuration are at or above the threshold, i.e., if the respective differences between the angles A 1 and B 1, the angles A 2 and B 2 and the angles A 3 and B 3 are each about 1% or more.The angle configurations may be referred to as "equal" if the difference in each of the three angles relative to the same angle in a different angle configuration (i.e., the angle A 1 is compared to the angle C 1 but the angle A 1 is not compared to the angle C 2 ) is within a tolerance factor. In one example, the tolerance factor is about 0.1% or less.In summary, in the first embodiment, the plurality of axial segments 26 exhibit pole-to-pole asymmetry and are alternately tilted about the axial direction X to reduce or eliminate radial forces and torque ripple.Second EmbodimentReferring to FIGS. 5-6, a second embodiment is illustrated by an interior permanent magnet machine that includes a rotor 112 having a central axis 114. A portion of a first axial segment 130 is shown in FIG. 5 and a portion of a second axial segment 132 is shown in FIG. 6. In each of the first and second embodiments, the angular configuration indicated by the first, second and third angles (50, 56, 62) is different for two rotor segments directly adjacent in the axial direction. Referring to FIGS. 5-6, the first axial segment 130 defines a first set of angular configurations 131 and the second axial segment 132 defines a second set of angular configurations 133. The rotor 112 is configured to have an axially asymmetric configuration such that the first set of angular configurations 131 is different from the second set of angular configurations 133. In the second embodiment, however, pole-to-pole symmetry exists in individual axial segments 26, as will be described in detail below.Referring to FIG. 5, the first axial segment 130 includes a first pole 166 (E) directly adjacent a second pole 168 (F). Referring to FIG. 6, the second axial segment 132 includes a third pole 170 (G) directly adjacent to a fourth pole 172 (H). Each of the first, second, third and fourth poles 166, 168, 170, 172 defines respective first, second, third and fourth pole axes 167, 169, 171, 173 extending from the central axis 14 and midway through or centrally through the respective poles. Each of the four poles 166, 168, 170, 172 (E - H) defines respective first, second, third, and fourth angle configurations 174, 176, 178, 180 [(E 1, E 2, E 3), ( F 1, F 2, F 3), ( G 1, G 2, G 3), ( H 1, H_NERea_, H_NERea_)] represented by the respective first, second, and third angles 50, 56, 62 described with reference to FIG. 2. The pattern represented by the first and second poles 166, 168 (E, F) may be repeated for the remainder of the first axial segment 130 (not shown). The pattern represented by the third and fourth poles 170, 172 (G, H) may be repeated for the remainder of the second axial segment 132 (not shown).Referring to FIG. 5, the first axial segment 130 exhibits pole-to-pole symmetry such that the first angular configuration 174 (E 1, E 2, E 3) and the second angular configuration 176 (F 1, F 2, F 3) are approximately the same. Referring to FIG. 6, the second axial segment 132 exhibits pole-to-pole symmetry such that the third angular configuration 178 (G 1, G 2, G 3) and the fourth angular configuration 180 (H 1, H 2, H 3) are the same. Thus, the respective groove sizes and shapes within individual axial segments 26 may be the same.Referring to FIGS. 5-6, the first angular configuration 174 (E 1, E 2, E 3) is different from the third angular configuration 178 (G 1, G 2, G 3) and from the fourth angular configuration 180 (H 1, H 2, H 3). The second angular configuration 176 (F 1, F 2, F 3) is different from both the third angular configuration 178 (G 1, G 2, G 3) and the fourth angular configuration 180 (H 1, H 2, H 2).In summary, non-pole cross orders are generated when the north pole angular placement is different than the south pole angular placement. In the first embodiment, non-pole passing orders are cancelled by tilting the rotor core segments in the axial direction. Due to a different angular placement between north pole and south pole, torque ripple and radial forces due to the pole passing order are reduced. In the second embodiment, the non-pole pass order is not generated because all axial segments 26 have the same angular placement of the north and south poles. However, by varying the angles between different axial segments 26, the torque ripple and radial force due to the pole passing order are reduced. It is the combination of these features that enables a reduction in both torque ripple and radial force due to the pole passing order. The first and second embodiments each reduce both the torque ripple and the radial force due to the pole passing order.The first, second, and third angles 50, 56, 62 described with reference to FIG. 2 may be optimized to obtain the desired level of balance for the respective rotors 12 and 112 (shown in FIGS. 5-6 ). This optimization may be performed empirically or by conventional computer modeling techniques known in the art. In one example, the first angle 50 is in a range of 51.5 to 57 degrees, the second angle 56 is in a range of about 48 to 53 degrees, and the third angle 62 is in a range of about 0 to 4.25 degrees.While the best modes and other embodiments for carrying out the disclosure have been described in detail, those familiar with the art to which this disclosure pertains will recognize various alternative constructions and embodiments for practicing the disclosure within the scope of the appended claims. In addition, the embodiments shown in the drawings or the characteristics of various embodiments mentioned in the present specification should not necessarily be construed as embodiments independent of each other. It is instead possible that each of the characteristics described in one of the examples of an embodiment may be combined with one or a plurality of other desired characteristics of other embodiments, resulting in further embodiments that are not described in words or by reference to the drawings. Accordingly, these other embodiments are within the scope of the appended claims.
Claims
An internal permanent magnet machine (17) (10) comprising: a rotor (12; 112) having a central axis (14; 114) and a plurality of axial segments (26; 30, 32, 34, 36; 130, 132) such that each segment of the plurality of axial segments (26; 30, 32, 34, 36; 130, 132) has at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) defining an angular configuration (74, 76, 78, 80; 174, 176, 178, 180) characterized by first, second, and third angles (50, 56, 62); wherein the plurality of axial segments (26; 30, 32, 34, 36; 130, 132) includes a first axial segment (30; 130) and a second axial segment (32; 132) positioned adjacent to each other in an axial direction (X); wherein the first axial segment (30; 130) defines a first set of angular configurations (74, 76; 174, 176) and the second axial segment (32; 132) defines a second set of angular configurations (78, 80; 178, 180); wherein the rotor (12, 112) is configured to have an asymmetric configuration in the axial direction (X) such that the first set of angular configurations (74, 76; 174, 176) is different from the second set of angular configurations (78, 80; 178, 180); wherein the at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) includes: a pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) that extends midway through the at least one pole (22; 42; from the central axis (14; 114); 66, 68, 70, 72; 166, 168, 170, 172); a first pair of slots (44) configured to be symmetric to the pole axis (46) and disposed in a radially inner first layer (18), the first angle (50) being defined between the pole axis (46) and a first centerline (48) of one slot of the first pair of slots (44); a second pair of slots (52) configured to be symmetric to the pole axis (46) and disposed in a radially outer second layer (20), the second angle (56) being defined between the pole axis (46) and a second centerline (54) of one slot of the second pair of slots (52); and a pair of outer slots (58) configured to be symmetrical to the pole axis (46) and formed proximate an outer surface (40) of the rotor (12; 112), wherein the third angle (62) between the pole axis (46) and a third centerline (60) is defined by a slot of the pair of outer slots (58), wherein: the first axial segment (30; 130) includes a first pole (A; E) directly adjacent to a second pole (B; F) and the second axial segment (32; 132) includes a third pole (C; G) directly adjacent to a fourth pole (D; H); and each of the first, second, third, and fourth poles (A, B, C, D; e, f, g, h) respective first, second, third and fourth angular configurations [(A 1, A 2, A 3), ( B 1, B 2, B 3), ( C 1, C 2, C 3), ( D 1, D2, D3)]; [(E 1, E 2, E 3), ( F 1, F 2, F 3), ( G 1, G 2, G 3), ( H 1, H2, H3)] represented by the respective first, second and third angles (50, 56, 62).The machine (10) of claim 1, wherein: the first axial segment (130) has a pole-to-pole symmetry such that the first angular configuration (E 1, E 2, E 3) and the second angular configuration (F 1, F 2, F 3) are the same; and the second axial segment (132) has a pole-to-pole symmetry such that the third angular configuration (G 1, G 2, G 3) and the fourth angular configuration (H 1, H 2, H 3) are the same.The machine (10) of claim 1, wherein the first (30) and second (32) axial rotor segments define different sets of angular configurations such that: the first angular configuration (A 1, A 2, A 3) is different from both the third angular configuration (C 1, C 2, C 3) and the fourth angular configuration (D 1, D 2, D 3); and the second angular configuration (B 1, B 2, B 3) is different from both the third angular configuration (C 1, C 2, C 3) and the fourth angular configuration (D 1, D 2, D 3).The machine (10) of claim 3, wherein the first angular configuration (A 1, A 2, A 3) is different from the third angular configuration (C 1, C 2, C 3) when a difference between any of the respective first (50) and / or second (56) and / or third (62) angles in the first angular configuration (A 1, A 2, A 3) relative to the third angular configuration (C 1, C2, C3) is at or above a threshold.The machine (10) of claim 3, wherein the first angular configuration (A 1, A 2, A 3) is different from the third angular configuration (C 1, C 2, C 3) when a respective difference between at least two of the respective first (50), second (56), and third (62) angles in the first angular configuration (A 1, A 2, A 3) relative to the third angular configuration (C 1, C2, C3) is at or above a threshold.The machine (10) of claim 3, wherein the first angular configuration (A 1, A 2, A 3) is different from the third angular configuration (C 1, C 2, C 3) when a respective difference between each of the respective first (50), second (56), and third (62) angles in the first angular configuration (A 1, A 2, A 3) relative to the third angular configuration (C 1, C2, C3) is at or above a threshold.An internal permanent magnet machine (17) (10) comprising: a rotor (12; 112) having a central axis (14; 114) and a plurality of axial segments (26; 30, 32, 34, 36; 130, 132) including a first axial segment (30; 130) and a second axial segment (32; 132) positioned adjacent to each other in an axial direction (X); wherein each segment of the plurality of axial segments (26; 30, 32, 34, 36; 130, 132) includes at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) having a pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and defining a respective angular configuration characterized by respective first (50), second (56) and third (62) angles; wherein the first axial segment (30; 130) defining a first set of angular configurations (74, 76; 174, 176) and the second axial segment (32; 132) defining a second set of angular configurations (78, 80; 178, 180); wherein the rotor (12; 112) is configured to have an asymmetric configuration in the axial direction (X) such that the first set of angular configurations (74, 76; 174, 176) is different from the second set of angular configurations (78, 80; 178, 180); wherein the respective first angle (50) of the at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) is defined between the pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and a first center line (48) of a groove of a first pair of grooves (44); wherein the respective second angle (56) of the at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) is defined between the pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and a second center line (54) of a groove of a second pair of grooves (52); wherein the respective third angle (62) of the at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) is defined between the pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and a third center line (60) of a groove of a pair of outer grooves (58); wherein the first axial segment (30) has a pole-to-pole asymmetry such that the first angular configuration (A 1, A 2, A 3) is different from the second angular configuration (B 1, B 2, B 3) ; wherein the second axial segment (32) has a pole-to-pole asymmetry such that the third angular configuration (C 1, C 2, C 3) is different from the fourth angular configuration (D 1, D2, D3); wherein adjacent segments of the plurality of axial segments (26; 30, 32, 34, 36; 130, 132) are alternately tilted around the axial direction (X); wherein the first angular configuration (A 1, A 2, A 3) and the fourth angular configuration (D 1, D 2, D 3) are the same; and wherein the second angular configuration (B 1, B 2, B 3) and the third angular configuration (C 1, C2, C3) are the same.An internal permanent magnet machine (17) (10) comprising: a rotor (12; 112) having a central axis (14; 114) and having a plurality of axial segments (26; 30, 32, 34, 36; 130, 132) including a first axial segment (30; 130) and a second axial segment (32; 132) positioned adjacent to each other in an axial direction (X); wherein each segment of the plurality of axial segments (26; 30, 32, 34, 36; 130, 132) includes at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) having a pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and defining a respective angular configuration characterized by respective first (50), second (56) and third (62) angles; wherein the first axial segment (30; 130) defining a first set of angular configurations (74, 76; 174, 176) and the second axial segment (32; 132) defining a second set of angular configurations (78, 80; 178, 180); wherein the rotor (12; 112) is configured to have an asymmetric configuration in the axial direction (X) such that the first set of angular configurations (74, 76; 174, 176) is different from the second set of angular configurations (78, 80; 178, 180); wherein the respective first angle (50) of the at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) is defined between the pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and a first centerline (48) of a groove of the first pair of grooves (44); wherein the respective second angle (56) of the at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) is defined between the pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and a second center line (54) of a groove of the second pair of grooves (52); wherein the respective third angle (62) of the at least one pole (22; 42; 66, 68, 70, 72; 166, 168, 170, 172) is defined between the pole axis (24, 46, 67, 69, 71, 73; 167, 169, 171, 173) and a third center line (60) of a groove of the pair of outer grooves (58); wherein the first axial segment (130) includes a first pole (E) directly adjacent to a second pole (F) and the second axial segment (132) includes a third pole (G) directly adjacent to a fourth pole (H); wherein each of the first, second, third and fourth poles (E, F, G, H) defines respective first, second, third and fourth angular configurations [(E 1, E 2, E 3), ( F 1, F 2, F 3), ( G 1, G 2, G 3), ( H 1, H2, H3)] represented by respective first (50), second (56) and third (62) angles; wherein the first angular configuration (E 1, E 2, E 3) is different from the third angular configuration (G 1, G 2, G 3) and from the fourth angular configuration (H 1, H 2, H 3) ; wherein the second angular configuration (F 1, F 2, F 3) is different from the third angular configuration (G 1, G 2, G 3) and from the fourth angular configuration (H 1, H 2, H 3) ; wherein the first axial segment (130) has pole-to-pole symmetry such that the first angular configuration (E 1, E 2, E 3) and the second angular configuration (F 1, F 2, F 3) are the same; and wherein the second axial segment (132) has pole-to-pole symmetry such that the third angular configuration (G 1, G 2, G 3) and the fourth angular configuration (H 1, H2, H3) are the same.
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rotor for a reluctance type rotating machine
DE102004036691A1