Rotating electric machine

Abstract

In a rotating electric machine in which the number of slots per pole per phase is 4 or more and an armature winding is configured as a distributed winding, magnetic flux barriers (63IN) are formed adjacent to both ends in the circumferential direction of first permanent magnets (62IN) constituting each magnetic pole, respectively, and P1 is the center angle of an arc connecting the centers in the circumferential direction of circumferentially adjacent slots (51S), P1 is the center angle of an arc connecting the centers in the circumferential direction of the first permanent magnets (62IN), and P2 is the center angle of an arc connecting the centers in the circumferential direction of the circumferentially adjacent slots (51S). When a magnetic flux barrier (63IN) is formed on a rotor core (61), a central angle [theta] 1 with respect to a rotation center (O) of a first arc portion (61M1) constituting an outer peripheral surface on the outside in the radial direction of the rotor core (61), which does not form the magnetic flux barrier (63IN), between magnetic poles adjacent in the circumferential direction is configured so as to ensure a first condition that [theta] 1 = P1 * 2.1 or less. Wherein P1 is a central angle of an arc connecting circumferential centers of circumferentially adjacent grooves.

Description

Technical Field

[0001] The present application relates to rotating electrical machines. Background Art

[0002] In rotating electrical machines such as motors and generators used in EV (Electric Vehicle) / HEV (hybrid Electric Vehicle), miniaturization, high efficiency, and low NV (Noise Vibration) are required from the perspectives of resource saving, extended vehicle cruising range, and quietness. Conventionally, in order to achieve a reduction in NV, a traction motor as a rotating electrical machine has been disclosed as follows: by setting a stator as a multi-slot structure to suppress the flux fluctuation in the air gap between the stator and the rotor, the torque pulsation, cogging torque, etc. are reduced.

[0003] That is, in the conventional traction motor as a rotating electrical machine, a first plurality of magnet pairs are formed in the laminated stack and arranged in a first V-shaped structure. In addition, in the laminated stack, a second plurality of permanent magnets larger than each of the first plurality of permanent magnets are formed as a second plurality of magnet pairs and arranged in a second V-shaped structure. The separation angle of the second magnet pair is formed to be smaller than the separation angle of the first magnet pair (for example, refer to Patent Document 1). Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Publication No. 2020-68654 ( Figure 3 , Figure 4 ) Summary of the invention Technical problem to be solved by the invention

[0005] The following method has been proposed in the above-mentioned existing traction motor: a multi-slot structure with 4 slots per pole per phase of the stator is adopted, and on this basis, the cogging torque is reduced by adjusting the size and configuration angle of the permanent magnets embedded in the rotor as a laminated stack. However, in this motor, although the cogging torque can be reduced, it may cause an increase in stator iron loss and lead to a decrease in motor efficiency. In particular, in a multi-slot structure with a large number of slots per pole per phase, since the number of teeth between the magnetic poles of the rotor increases, the increase in the above-mentioned iron loss becomes larger, and there is a problem of reduced motor efficiency. The present application discloses a technology for solving the above-mentioned problems, and an object of the present application is to provide a rotating electrical machine having high efficiency even in a multi-slot structure in which the number of slots per pole per phase is large. Technical means for solving technical problems

[0006] The rotating electrical machine disclosed in the present application comprises: a stator having a plurality of teeth protruding radially inward from an annular yoke portion, wherein an armature winding is wound around a plurality of slots formed between the teeth; and a rotor having a plurality of magnetic poles formed of permanent magnets and a rotor core having a magnetic flux barrier formed thereon, The number of slots per pole per phase obtained by dividing the total number of slots by the number of phases and the number of magnetic poles of the rotor is 4 or more, and the armature winding is configured as a distributed winding. In the rotating electrical machine, A first magnetic flux barrier serving as the magnetic flux barrier is formed adjacent to both ends in the circumferential direction of the first permanent magnet constituting each of the magnetic poles, The central angle θ1 of the first arc portion constituting the radially outer outer peripheral surface of the rotor core where the flux barrier is not formed between the circumferentially adjacent magnetic poles is configured to ensure the first condition. The first condition is that θ1=P1×2.1 or less. Wherein, P1 is the central angle of the arc connecting the circumferential centers of the circumferentially adjacent grooves. Effects of the Invention

[0007] According to the rotating electrical machine disclosed in the present application, it is possible to obtain a rotating electrical machine having high efficiency even in a multi-slot structure in which the number of slots per pole per phase is large. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram showing a cross section parallel to the axial direction in the rotating electrical machine according to the first embodiment. Figure 2 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the first embodiment. Figure 3 It is a cross-sectional view perpendicular to the axial direction Y in the rotating electrical machine of the comparative example. Figure 4 It is a cross-sectional view perpendicular to the axial direction Y in the rotating electrical machine of the comparative example. Figure 5 It is a cross-sectional view perpendicular to the axial direction Y in the rotating electrical machine of the comparative example. Figure 6 This is a diagram showing a curve of the iron loss characteristic of the rotating electrical machine when the central angle θ1 is changed. Figure 7 This is a diagram for explaining the principle of increase in iron loss in a rotating electrical machine. Figure 8 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the first embodiment. Fig. 9 It is a cross-sectional view perpendicular to the axial direction Y in the rotating electrical machine of the comparative example. Fig.10 It is a cross-sectional view perpendicular to the axial direction Y in the rotating electrical machine of the comparative example. Fig.11 It is a cross-sectional view perpendicular to the axial direction Y in the rotating electrical machine of the comparative example. Fig.12 1 is a diagram showing a curve of the iron loss characteristic of the rotating electrical machine when the central angle θ2 is changed. Fig.13 This is a diagram for explaining the principle of increase in iron loss in a rotating electrical machine. Fig.14 It is a diagram showing a curve of torque characteristics in a rotating electrical machine. Fig.15 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the first embodiment. Fig.16 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the second embodiment. Fig.17 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the second embodiment. Fig.18 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the second embodiment. Fig.19 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the second embodiment. Fig. 20 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the second embodiment. Fig.21 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine according to the second embodiment. Fig. 22 2 is a diagram showing magnetomotive force distribution in a rotating electrical machine. Fig.23 2 is a diagram showing magnetomotive force distribution in a rotating electrical machine. DETAILED DESCRIPTION

[0009] Implementation method 1. Hereinafter, the rotating electrical machine according to the first embodiment will be described using the drawings. In addition, in the figure, directions of the annular rotating electrical machine are represented as circumferential direction C, radial direction X, and axial direction Y. Figure 1 1 is a schematic diagram showing a cross section parallel to the axial direction Y in the rotating electrical machine 100 according to the first embodiment.

[0010] like Figure 1 As shown, the rotary electric machine 100 includes a cylindrical housing 70 , a stator 50 accommodated therein, and a rotor 60 disposed coaxially with the stator 50 on the radially inner side X1 of the stator 50 . The housing 70 includes a bottomed cylindrical frame 71 and an end plate 72 that closes an opening of the frame 71 . The stator 50 is fixed to the frame 71 in a fitted state at the radially inner side X1 of the frame 71 . The rotor 60 is rotatably supported by a rotation shaft 74 provided at a center portion of an end plate 72 of a frame 71 via a bearing 73 .

[0011] Figure 2 This is a diagram showing a part of a cross section perpendicular to the axial direction of the rotating electrical machine 100 according to Embodiment 1. In this figure, only a part corresponding to about 1 / 4 of the circumference of the annular rotating electrical machine 100 is shown. like Figure 2 As shown, the stator 50 includes a stator core 51 formed by laminating electromagnetic steel plates, and three-phase coils 55 of U, V, and W as armature windings wound around the stator core 51 . The stator core 51 includes an annular core back 51B, a plurality of teeth 51T extending radially inwardly X1 from the core back 51B, and a plurality of slots 51S formed by being surrounded by adjacent teeth 51T and the core back 51B. The coils 55 are accommodated in the slots 51S.

[0012] In the stator 50 of the present embodiment, 96 slots 51S are formed at equal intervals in the circumferential direction C. Here, if the central angle of the arc 61MS connecting the circumferential centers of the circumferentially adjacent slots 51S with respect to the center point O of the rotor 60 is set to P1, the central angle P1 is 360° / 96=3.75°. In addition, the connection method of the coil 55 is distributed winding, and the coils 55 in each slot 51S are connected in series or in parallel.

[0013] The rotor 60 includes an annular rotor core 61 as a rotor core and permanent magnets 62 (62IN, 62OUT) constituting magnetic poles formed at predetermined intervals in the circumferential direction of the rotor core 61. The permanent magnets 62 (62IN, 62OUT) are inserted into magnet insertion holes of the rotor core 61. Each magnetic pole has a two-layer structure in which a pair of permanent magnets 62IN as first permanent magnets are arranged on the radially inner side X1 and a pair of permanent magnets 62OUT as second permanent magnets are arranged on the radially outer side X2. Four permanent magnets 62 are embedded in each pole. The pair of permanent magnets 62IN and 62OUT are respectively arranged in a V-shape so as to expand toward the outer peripheral surface 61M of the rotor 60 .

[0014] In the rotor core 61, magnetic flux barriers for preventing magnetic flux from leaking from the permanent magnet 62 are formed adjacent to both ends of the permanent magnet 62. That is, a magnetic flux barrier 63IN is formed as a first magnetic flux barrier in the permanent magnet 62IN in communication with both ends of the magnet insertion hole, and a magnetic flux barrier 63OUT is formed as a second magnetic flux barrier in the permanent magnet 62OUT in communication with both ends of the magnet insertion hole. Furthermore, the flux barriers 63IN are formed to extend from both ends of the permanent magnet 62IN in the circumferential direction C toward the radially outer side X2 at an extension angle θ3 set with respect to the permanent magnet 62IN.

[0015] In this embodiment, the number of magnetic poles of the rotor 60 is 8, and the number of slots per pole per phase q obtained by dividing the total number of slots 96 by the number of phases 3 and the number of magnetic poles 8 is 96 / (8*3) = 4. The larger the number of slots per pole per phase q, the more multi-slot structure the stator 50 has. Thus, in the rotating electrical machine 100 having a multi-slot structure, the number of slots 51S facing the outer peripheral surface 61M of the rotor core 61 between magnetic poles adjacent to each other in the circumferential direction C increases.

[0016] Here, if Figure 2 As shown, between adjacent magnetic poles in the circumferential direction C, a region of the rotor core 61 where no flux barrier is formed near the outer peripheral surface 61M is defined as J1, and an arc of the outer peripheral surface 61M on the radially outer side X2 constituting the region J1 is defined as a first arc portion 61M1. If the central angle of the first arc portion 61M1 with respect to the rotation center O of the rotor 60 is θ1, in the present embodiment, the central angle θ1 is configured to ensure a first condition of θ1=P1×2.1 or less. The vicinity of the outer peripheral surface 61M of the rotor core 61 is a region within a range set from the outer peripheral surface 61M to the radial inner side X1. This set range is set according to the range of magnetic flux that generates a short circuit in the magnetic path of tooth 51T→inter-pole→tooth 51T described later.

[0017] Here, the effect of setting the central angle θ1 of the first arc portion 61M1 with respect to the rotation center O to be equal to or less than P1×2.1 will be described using experimental results using a motor of a rotary electric machine as a comparative example in which the value of θ1 is changed. Figure 3 It is a cross-sectional view perpendicular to the axial direction Y in the rotary electric machine 100EX1 of the comparative example when θ1=P1×0.85. Figure 4 This is a cross-sectional view perpendicular to the axial direction Y in the rotary electric machine 100EX2 of the comparative example when θ1=P1×2.08. Figure 5It is a cross-sectional view perpendicular to the axial direction Y in the rotary electric machine 100EX3 of the comparative example when θ1=P1×2.32. Figure 6 This is a diagram showing a curve of the iron loss characteristic of the rotating electrical machine when the central angle θ1 is changed. Figure 7 This is a diagram for explaining the principle of increase in iron loss in a rotating electrical machine.

[0018] In the electric motors for electric vehicles which are rotating motors, the efficiency in the medium speed area and the low load area during urban driving is emphasized. Therefore, under the conditions of low current and current phase of 90°, electromagnetic field analysis was implemented using each rotating motor 100EX1, EX2, EX3, and rotating motors other than these rotating motors 100EX1, EX2, EX3 with a center angle θ1. in addition, Figure 6 In the figure, normalization is performed under the condition that the iron loss is θ1=P1×2.08.

[0019] according to Figure 6 It can be seen that the inflection point where the iron loss changes sharply with respect to the center angle θ1 is located at θ1=P1×2.08. This is because when the number of slots 51S of the stator 50 facing the first arc portion 61M1 constituting the center angle θ1 increases, Figure 7 As shown by the path of the middle arrow, the magnetic flux short-circuited in the magnetic path of tooth 51T→between magnetic poles→tooth 51T increases through the area where the magnetic flux barrier is not formed near the outer peripheral surface 61M of the rotor core 61, and the magnetic flux density in the tooth 51T increases, which leads to an increase in the stator iron loss. Therefore, if the central angle θ1 constituting the first arc portion 61M1 is configured to ensure the first condition of being set to 2.1 times or less of P1, the stator iron loss can be reduced, and the efficiency of the rotating electrical machine can be improved.

[0020] Here, in the rotating electric machine with the number of slots per pole per phase q=2 and the rotating electric machine with the number of slots per pole per phase q=4, even if the angle of the center angle θ1 is the same, the number of slots 51S facing the first arc portion 61M1 in the rotating electric machine with the number of slots per pole per phase q=4 is doubled compared to the rotating electric machine with the number of slots per pole per phase q=2. Although the change of the magnetic flux in the air gap between the stator and the rotor is suppressed by the multi-slot, the effect of reducing the torque pulsation and the cogging torque is obtained, but when the number of slots facing the first arc portion 61M1 is large, the iron loss increases. In particular, when the rotor designed for the stator with the number of slots per pole per phase q=2 to 3 in the electric motor for electric vehicles is directly applied to the stator with the number of slots per pole per phase q=4 or more without changing the structure, the possibility of increasing the iron loss due to the above principle becomes high. In the rotating electric machine of the present embodiment, even in the case of a multi-slot structure, since the center angle θ1 is designed to ensure the first condition as described above, both the quiet effect due to the reduction of the torque pulsation due to the multi-slot and the high efficiency due to the reduction of the stator iron loss can be obtained.

[0021] Furthermore, the rotating electrical machine may have the following structure. Figure 8 This is a diagram showing a part of a cross section perpendicular to the axial direction of the rotating electrical machine 100A according to the first embodiment, and only a part corresponding to about 1 / 4 of the circumference of the annular rotating electrical machine 100A is shown. In each magnetic pole, near the outer peripheral surface 61M between the flux barrier 63IN and the flux barrier 63OUT, an area of ​​the rotor core 61 where no flux barrier is formed is defined as J2, and an arc of the outer peripheral surface 61M on the radially outer side X2 constituting the area J2 is defined as a second arc portion 61M2.

[0022] The vicinity of the outer peripheral surface 61M of the rotor core 61 is a region within a range set from the outer peripheral surface 61M to the radial inner side X1. This set range is set according to the range of magnetic flux that generates a short circuit in the magnetic path between the magnet layers → the stator 50 → between the magnetic poles described later. If the central angle of the second arc portion 61M2 with respect to the rotation center O is θ2, in the present embodiment, the central angle θ2 is configured to ensure a first condition of θ2=P1×1.65 or less.

[0023] Here, the effect of setting the central angle θ2 of the second arc portion 61M2 with respect to the rotation center O to be equal to or less than P1×1.65 will be described using experimental results using a motor of a rotary electric machine as a comparative example in which the value of θ2 is changed. Fig. 9 It is a cross-sectional view perpendicular to the axial direction Y in the rotary electric machine 100EX4 of the comparative example when θ2=P1×0.75. Fig.10It is a cross-sectional view perpendicular to the axial direction Y in the rotary electric machine 100EX5 of the comparative example when θ2=P1×1.62. Fig.11 It is a cross-sectional view perpendicular to the axial direction Y in the rotary electric machine 100EX6 of the comparative example when θ2=P1×2.32. Fig.12 1 is a diagram showing a curve of the iron loss characteristic of the rotating electrical machine when the central angle θ2 is changed. Fig.13 This is a diagram for explaining the principle of increase in iron loss in a rotating electrical machine.

[0024] Electromagnetic field analysis was performed using rotating electrical machines 100EX4, EX5, and EX6 under the conditions of low current and current phase 90 degrees, similarly to the case of varying θ1. While ensuring the first condition of θ1 being equal to or less than P1×2.1, θ2 was varied and analyzed. in addition, Fig.12 In the figure, normalization is performed under the condition that the iron loss is θ2 = P1 × 1.62.

[0025] according to Fig.12 It can be seen that in the region where the center angle θ2 is less than P1×1.65, the iron loss of the motor for the center angle θ2 decreases sharply. This is because when the number of slots 51S of the stator 50 facing the second arc portion 61M2 constituting the center angle θ2 increases, Fig.13 As shown by the arrow in the path, the magnetic flux short-circuited between the magnet layers → stator 50 → magnetic poles increases, and the magnetic flux density in the tooth 51T increases, resulting in an increase in the stator iron loss. Thus, the first condition of setting the center angle θ2 constituting the second arc portion 61M2 to be less than 1.65 times P1 is ensured. Thus, by increasing the magnetic resistance of the above-mentioned path, the magnetic flux concentrated on a specific tooth of the stator is dispersed, thereby alleviating the local concentration of the magnetic flux density of the tooth to reduce the stator iron loss, and achieving high efficiency of the rotating electrical machine.

[0026] The iron loss characteristics when θ2 is changed have been described above. The torque characteristics when θ2 is changed will be described below. Fig.14 This is a diagram showing a curve of the torque characteristic of the rotating electrical machine when θ2 is changed while the first condition that θ2 is equal to or less than P1×1.65 is ensured. As described above, by reducing the central angle θ2, the length of the second arc portion 61M2 is reduced, thereby increasing the magnetic resistance. On the other hand, if the central angle θ2 is made extremely small, Fig.14 This will cause a drop in torque.

[0027] Therefore, by making the center angle θ2 greater than θ1=P1×1 while ensuring the first condition of being less than P1×1.65, the torque reduction can be suppressed to a minimum, that is, the torque reduction can be suppressed to less than 1% compared with the rotating motor with the baseline structure of θ2=P1×1.62, and the high efficiency of the rotating motor can be achieved.

[0028] Furthermore, the rotating electrical machine may be configured as described below. Fig.15 This is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electrical machine 100B according to the first embodiment. Above Figure 2 In the illustrated rotating electrical machine 100 , each magnetic pole has a two-layer structure including a pair of permanent magnets 62IN as first permanent magnets constituting a first layer and a pair of permanent magnets 62OUT as second permanent magnets constituting a second layer. Fig.15 In the rotating electrical machine 100B shown, the magnetic pole has a structure of three layers in total, including a pair of permanent magnets 62IN as first permanent magnets constituting the first layer, and a pair of permanent magnets 62OUT as second permanent magnets constituting two layers.

[0029] The effect of having each magnetic pole have a multi-layer structure in the radial direction will be described. In the two-layer structure obtained by arranging two layers of magnetic poles in the radial direction, the magnetic circuit in the rotor can be made close to the configuration along the excitation magnetic flux of the stator. Therefore, the reluctance torque can be effectively utilized, and the torque can be improved. In addition, in the multi-layer configuration that can effectively utilize the reluctance torque, the two-layer structure can relatively suppress the number of magnets used, thereby reducing the number of magnet insertions during rotor manufacturing, which helps to suppress manufacturing costs.

[0030] However, when the pole is a two-layer structure, the number of magnet layers used is small, so it is easy to become a structure with a large θ1 or θ2. For example, if a rotor with an 8-pole two-layer structure and designed for 24 slots (q=1), 48 slots (q=2), or 72 slots (q=3) facing less than q=4 is directly used with 96 slots (q=4), the value of P1 of θ1 or θ2 is not considered enough, which can easily cause an increase in iron loss. In the case of this structure, Fig.15 The rotating electrical machine 100B as shown is effective. By increasing the number of magnetic pole layers from a two-layer structure to a three-layer structure, the degree of freedom of the magnetic pole shape increases, and the reluctance torque can be used more effectively, thereby improving the torque.

[0031] In addition, the pair of permanent magnets constituting each magnetic pole layer is not limited to a V-shaped configuration extending toward the outer peripheral surface of the rotor, and may also be a flat plate configuration, The magnet configuration such as type configuration has nothing to do with the shape and number of magnet insertion holes, the shape and number of permanent magnets, etc. For example, in a rotor having flat-plate-arranged magnetic poles, between magnetic poles having only one permanent magnet as the first permanent magnet, a central angle θ1 of a first arc portion of a radially outer peripheral surface of a rotor core where no flux barrier is formed is configured to ensure the first condition.

[0032] In addition, although the structure of 8 poles and 96 slots is shown, the number of poles and the number of slots are not limited to this, the above-mentioned effect can be obtained. In addition, q is a number greater than 4 and is not limited to an integer. In addition, the purpose of the magnetic flux barrier is to suppress the leakage of magnetic flux, and therefore, it can be composed of a material having a lower magnetic permeability than the electromagnetic steel sheet, such as air, resin, etc.

[0033] In addition, electric motors for electric vehicles are required to have higher outputs. Therefore, due to the limited space for vehicle installation and the requirements for torque / output density, the outer diameter of the stator core is often configured to be When designing a high-output electric motor with a diameter of 150 mm or more, as described below, the number of poles of the rotor is preferably 6 or more.

[0034] For high torque and high output design of electric motors, the optimal split ratio (rotor core outer diameter / stator core outer diameter) needs to be ensured to be around 60-80%. The smaller the number of poles, the larger the pole pitch (the central angle of the arc length of the rotor core relative to each pole), and the more magnetic flux flows in the back of the stator core. In order to avoid magnetic saturation at the back of the core, the back of the core needs to be designed to be thicker, but when the number of poles decreases, the proportion of the thickness of the back of the core in the radial length of the motor increases, so it is impossible to ensure a 60-80% shunt ratio. Therefore, in electric motors for electric vehicles, a small-pole design with less than 4 poles is avoided, and a structure with more than 6 poles is preferred.

[0035] In the adjustment of θ1 for ensuring the first condition, for example, Figure 2 The extension angle θ3 of the flux barrier 63IN shown in FIG. Figure 2 As shown, the radially outer side X2 end of the magnetic flux barrier 63IN may be formed to extend along the outer peripheral surface 61M of the rotor core 61 .

[0036] The rotating electrical machine of the present embodiment configured as described above includes: a stator having a plurality of teeth protruding radially inward from an annular yoke portion, wherein an armature winding is wound around a plurality of slots formed between the teeth; and a rotor having a plurality of magnetic poles formed of permanent magnets and a rotor core having a magnetic flux barrier formed thereon, The number of slots per pole per phase obtained by dividing the total number of slots by the number of phases and the number of magnetic poles of the rotor is 4 or more, and the armature winding is configured as a distributed winding. In the rotating electrical machine, A first magnetic flux barrier serving as the magnetic flux barrier is formed adjacent to both ends in the circumferential direction of the first permanent magnet constituting each of the magnetic poles, The central angle θ1 of the first arc portion constituting the radially outer outer peripheral surface of the rotor core where the flux barrier is not formed between the circumferentially adjacent magnetic poles is configured to ensure the first condition. The first condition is that θ1=P1×2.1 or less. Wherein, P1 is the central angle of the arc connecting the circumferential centers of the circumferentially adjacent grooves. Thus, even in a multi-slot structure in which the number of slots per pole per phase is large, a highly efficient rotating electrical machine can be provided.

[0037] Furthermore, in the rotating electrical machine of the present embodiment configured as described above, The magnetic pole is formed into multiple layers by arranging second permanent magnets adjacent to both ends in the circumferential direction and forming second flux barriers serving as the flux barriers on the radially outer side of the first permanent magnet. In each of the magnetic poles, a central angle θ2 of a second arc portion of the radially outer outer peripheral surface of the rotor core between the first flux barrier and the second flux barrier where the flux barrier is not formed is configured to ensure the first condition. The first condition is that θ2=P1×1.65 or less. Thus, by increasing the magnetic resistance between the first permanent magnet and the second permanent magnet → the stator → the magnetic poles and dispersing the magnetic flux interlinked with the teeth, local concentration of the magnetic flux density can be alleviated and the stator iron loss can be reduced.

[0038] Furthermore, in the rotating electrical machine of the present embodiment configured as described above, The central angle θ2 is configured to ensure the first condition that it is equal to or greater than P1×1. This can reduce the stator iron loss and suppress the decrease in torque.

[0039] Furthermore, in the rotating electrical machine of the present embodiment configured as described above, The first flux barrier is formed to extend radially outward from both ends of the first permanent magnet in the circumferential direction at an extension angle θ3 set with respect to the first permanent magnet. The extension angle θ3 is adjusted so as to ensure the first condition. By adjusting the extension angle θ3 in this way, it becomes easy to adjust θ1 and θ2 for ensuring the first condition.

[0040] Implementation method 2. Hereinafter, Embodiment 2 of the present application will be described with reference to the drawings, focusing on the differences from Embodiment 1 described above. The same reference numerals are given to the same parts as those in Embodiment 1 described above, and the description thereof will be omitted. Fig.16 1 is a diagram showing a portion of a cross section perpendicular to the axial direction of a rotating electrical machine 200 according to the second embodiment. In this diagram, only a portion corresponding to approximately 1 / 4 of the circumference of the annular rotating electrical machine 200 is shown. Fig.17 yes Fig.16 2 is a partially enlarged cross-sectional view of the rotating electrical machine 200 , but as an example, the diagram shows a case where the shape of the radially outer side X2 end of the magnetic flux barrier 63IN is different. Fig.18 This is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electrical machine 200A according to the second embodiment.

[0041] In the rotating electrical machine 200 , 200A of the present embodiment, a flux barrier 263M as a third flux barrier independently configured without being connected to the flux barriers 63IN, 63OUT is provided near the outer peripheral surface 61M of the rotor core 61 between the magnetic poles.

[0042] Fig.16 In the rotating electric machine 200 shown in the figure, in the definition of the first arc portion 61M1 constituting θ1, the arc obtained by subtracting the circumferential length of the magnetic flux barrier 263M from the length of the arc of the rotor core 61 between adjacent magnetic flux barriers 63IN between each magnetic pole is set as the first arc portion 61M1. That is, the first arc portion 61M1 in the rotating electric machine 200 of the present embodiment is obtained by adding the arcs 61M1A and 61M1B constituting the outer peripheral surface of the radial outer side X2 of the rotor core 61 where the magnetic flux barrier 263M is not formed between the magnetic flux barriers 63IN between adjacent magnetic poles in the circumferential direction C.

[0043] In addition, if Fig.18 As in the illustrated rotating electrical machine 200A, a flux barrier 263M as a third flux barrier may be formed between one side of the flux barrier 63OUT of each magnetic pole in the circumferential direction C and the other side of the flux barrier 63IN in the circumferential direction C. In the definition of the second arc portion constituting θ2 at this time, the arc obtained by subtracting the circumferential length of the flux barrier 263M from the length of the arc of the outer peripheral surface 61M of the rotor core 61 between the flux barrier 63OUT and the flux barrier 63IN is set as the second arc portion 61M2. That is, the second arc portion 61M2 in the present embodiment is obtained by adding together the arcs 61M2C and 61M2D constituting the outer peripheral surface of the radially outer side X2 of the rotor core 61 where the flux barrier 263M is not formed between the flux barrier 63OUT and the flux barrier 63IN.

[0044] Thus, by configuring the independently constructed flux barrier 263M, the parameters that change the magnetic permeability and magnetomotive force of the rotor can be increased, thereby expanding the degree of freedom in design. For example, by adjusting its position and shape, the change of the excitation flux of the stator 50 can be offset, thereby reducing torque pulsation. In addition, in the case of a very large magnetic flux barrier, the magnetic flux barrier between the rotor and the outer peripheral surface 16M is applied during high-speed rotation. Fig.17 The stress of the bridge portion 261B shown in FIG. 1 increases, which may lead to a decrease in the strength against centrifugal force. In this case, the independently formed magnetic flux barrier 263M may be configured to Fig.17 The ribs 261R shown are formed between the flux barriers, so that the stress applied to the bridge portion 261B can be dispersed to the ribs 261R, thereby contributing to the improvement of the strength against the centrifugal force.

[0045] In order to prevent deformation of the rotor core 61 due to centrifugal force, etc., it is possible to consider expanding the radial width X of the bridge portion 261B to relieve stress. However, if the width of the bridge portion 261B is expanded, the torque will decrease due to the increase in leakage flux. Therefore, in order to ensure the strength against centrifugal force and achieve high torque, it is necessary to set the radial width X of the bridge portion 261B as narrow as possible, for example, to less than 2% of the rotor diameter. On the other hand, if the width of the bridge portion 261B is too narrow, the magnetic flux becomes easier to flow through the stator core 51, which will lead to an increase in the stator iron loss. Therefore, the radial width X of the bridge portion 261B can be set to less than 2% of the rotor diameter, and its value can be further adjusted.

[0046] More modified examples in which the arrangement positions of the flux barriers 263M are adjusted are shown below. Fig.19 This is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electrical machine 200B according to the second embodiment. Fig. 20 This is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electrical machine 200C according to the second embodiment. Fig.21 This is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electrical machine 200D according to the second embodiment.

[0047] like Fig.19As shown, the flux barrier 263M may be arranged between the flux barriers 63IN adjacent to each other in the circumferential direction C and between the flux barrier 63OUT and the flux barrier 63IN in each magnetic pole.

[0048] In addition, if Fig. 20 As shown, as a method for obtaining a better effect, the magnetic flux barrier 263M may be configured such that its radially outermost X2 portion is arranged radially outermost X2 than the radially outermost X2 portions of the magnetic flux barriers 63IN and 63OUT. When the distance between the flux barrier 263M and the outer peripheral surface 61M of the rotor core 61 is long, the magnetic flux is easily short-circuited between the flux barrier 263M and the outer peripheral surface 61M, and the function as a flux barrier is reduced. Fig. 20 By configuring the rotating electrical machine 200C in such a manner that the distance between the flux barrier 263M and the outer peripheral surface 61M of the rotor core 61 is shortened, the function of the flux barrier is enhanced, and the effect of reducing the iron loss is increased.

[0049] In addition, if Fig.21 As shown, the flux barrier 263M may be arranged on the outer peripheral surface 61M side of the rotor core 61 in a manner of cutting out the outer peripheral surface 61M on the radially outer side X2 of the rotor core 61 . In this case, the effect of providing the above-mentioned flux barrier 263M can be obtained in the same manner.

[0050] Fig. 22 This is a diagram showing the magnetomotive force distribution in a rotating electrical machine having a structure in which the magnetic flux barrier 263M is not provided. Fig.23 It is a diagram showing the magnetomotive force distribution in the rotating electrical machine after the magnetic flux barrier 263M is provided. like Fig. 22 , 23 As shown, by providing the flux barriers 263M and adjusting their configuration positions, the magnetomotive force distribution of the rotor 60 can be adjusted to be close to a sine wave, thereby reducing torque pulsation.

[0051] In the rotating electrical machine of the present embodiment configured as described above, A third magnetic flux barrier formed independently of the first magnetic flux barrier and the second magnetic flux barrier as the magnetic flux barrier is provided, The third magnetic flux barrier is arranged on at least one of the following: between one side of the second magnetic flux barrier in the circumferential direction and the other side of the first magnetic flux barrier in the circumferential direction in each of the magnetic poles; and Between the magnetic poles adjacent to each other in the circumferential direction and between the first magnetic flux barriers adjacent to each other in the circumferential direction, The first arc portion is the sum of arcs constituting the radially outer outer peripheral surface of the rotor core where the third magnetic flux barrier is not formed, between the magnetic poles adjacent in the circumferential direction. The second arc portion is the sum of arcs constituting the radially outer outer peripheral surface of the rotor core where the third flux barrier is not formed, between the first flux barrier and the second flux barrier in each of the magnetic poles. Therefore, by configuring the third flux barrier and ensuring the first condition at the center angle θ2, the torque pulsation can be reduced, the strength against centrifugal force can be improved, and at the same time, the local concentration of the magnetic flux density of the tooth can be alleviated to reduce the iron loss, thereby making the rotating electrical machine more efficient.

[0052] Furthermore, in the rotating electrical machine of the present embodiment configured as described above, The arrangement position of the third flux barrier is adjusted so that the magnetomotive force distribution of the rotor approaches a sinusoidal wave. This makes it possible to obtain a quieter rotating electrical machine with reduced torque pulsation.

[0053] Although the present application describes various exemplary embodiments and examples, various features, methods, and functions described in one or more embodiments are not limited to application in specific embodiments and may be applied to the embodiments alone or in various combinations. Therefore, numerous modifications not shown in the examples are conceivable within the technical scope disclosed in the present application, including, for example, the case where at least one structural element is modified, added, or omitted, and the case where at least one structural element is extracted and combined with structural elements of other embodiments. Description of symbols

[0054] 50 Stator 51 stator core 51B Yoke 51T tooth 51S slot 61 rotor core (rotor iron core) 62IN permanent magnet (1st permanent magnet) 62OUT permanent magnet (second permanent magnet) 63IN flux barrier (1st flux barrier) 63OUT flux barrier (second flux barrier) 263M 3rd Flux Barrier (Flux Barrier) 55 coil (armature winding) 100, 100A, 100B, 200A, 200B, 200C, 200D rotating electrical machines.

Claims

1. A rotating electrical machine, comprising: a stator having a plurality of teeth protruding radially inward from an annular yoke portion, wherein an armature winding is wound around a plurality of slots formed between the teeth; and A rotor having a plurality of magnetic poles formed of permanent magnets and a rotor core having a magnetic flux barrier, The number of slots per pole per phase obtained by dividing the total number of slots by the number of phases and the number of magnetic poles of the rotor is 4 or more, and the armature winding is configured as a distributed winding. The rotating electrical machine is characterized in that: A first magnetic flux barrier serving as the magnetic flux barrier is formed adjacent to both ends in the circumferential direction of the first permanent magnet constituting each of the magnetic poles, The central angle θ1 of the first arc portion constituting the radially outer outer peripheral surface of the rotor core where the flux barrier is not formed between the circumferentially adjacent magnetic poles is configured to ensure the first condition. The first condition is that θ1=P1×2.1 or less. Wherein, P1 is the central angle of the arc connecting the circumferential centers of the circumferentially adjacent grooves.

2. The rotating electrical machine according to claim 1, characterized in that The magnetic pole is formed in multiple layers by arranging second permanent magnets each having a second flux barrier as the flux barrier adjacent to both ends in the circumferential direction on the radially outer side of the first permanent magnet. In each of the magnetic poles, a central angle θ2 of a second arc portion of an outer peripheral surface of the rotor core on the radially outer side between the first flux barrier and the second flux barrier where the flux barrier is not formed is configured to ensure the first condition. The first condition is that θ2=P1×1.65 or less.

3. The rotating electrical machine according to claim 2, characterized in that The central angle θ2 is configured to ensure the first condition that it is equal to or greater than P1×1.

4. The rotating electrical machine according to claim 2 or 3, characterized in that: The first flux barrier is formed to extend radially outward from both ends of the first permanent magnet in the circumferential direction at an extension angle θ3 set with respect to the first permanent magnet. The extension angle θ3 is adjusted so as to ensure the first condition.

5. The rotating electrical machine according to any one of claims 2 to 4, characterized in that A third magnetic flux barrier formed independently of the first magnetic flux barrier and the second magnetic flux barrier as the magnetic flux barrier is provided, The third magnetic flux barrier is arranged on at least one of the following: between one side of the second magnetic flux barrier in the circumferential direction and the other side of the first magnetic flux barrier in the circumferential direction in each of the magnetic poles; and Between the magnetic poles adjacent to each other in the circumferential direction and between the first magnetic flux barriers adjacent to each other in the circumferential direction, The first arc portion is the sum of arcs constituting the radially outer outer peripheral surface of the rotor core where the third magnetic flux barrier is not formed, between the magnetic poles adjacent in the circumferential direction. The second arc portion is the sum of arcs constituting the radially outer outer peripheral surface of the rotor core where the third flux barrier is not formed, between the first flux barrier and the second flux barrier in each of the magnetic poles.

6. The rotating electrical machine according to claim 5, characterized in that The arrangement position of the third flux barrier is adjusted so that the magnetomotive force distribution of the rotor approaches a sinusoidal wave.

7. The rotating electrical machine according to claim 5 or 6, characterized in that: The radially outer portion of the third magnetic flux barrier is arranged radially outwardly relative to the radially outer portions of the first magnetic flux barrier and the second magnetic flux barrier.

8. The rotating electrical machine according to any one of claims 5 to 7, characterized in that The third flux barrier is arranged on the outer peripheral surface side of the rotor core so as to cut out the radially outer side of the rotor core.

9. The rotating electrical machine according to any one of claims 2 to 8, characterized in that The magnetic pole of the multi-layer structure has a two-layer structure, including the first magnetic flux barrier constituting the first layer and the second magnetic flux barrier constituting the second layer.

10. The rotating electrical machine according to any one of claims 2 to 8, characterized in that The multi-layered magnetic pole has a structure of three or more layers, including a first flux barrier constituting a first layer and a plurality of second flux barriers constituting second and subsequent layers.

11. The rotating electrical machine according to any one of claims 2 to 10, characterized in that At least one of the bridge portions formed between the first flux barrier and the second flux barrier and the outer peripheral surface of the rotor core is formed so that a radial width of the bridge portion is less than or equal to 2% of a diameter of the rotor.

12. The rotating electrical machine according to any one of claims 2 to 11, characterized in that The first permanent magnet and the second permanent magnet are configured as a pair of magnets having a V-shape arranged to expand toward the outer peripheral surface side of the rotor.

13. The rotating electrical machine according to any one of claims 1 to 12, characterized in that The number of magnetic poles is set to be 6 or more.

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