WO2024084542A1

WO2024084542A1 - Rotary electric machine

Info

Publication number: WO2024084542A1
Application number: PCT/JP2022/038543
Authority: WO
Inventors: 慎介茅野; 仁志磯田; 貴之飯田
Original assignee: 三菱電機株式会社
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2024-04-25

Abstract

In a rotary electric machine in which the number of slots in each pole and each phase is four or more and armature windings are configured as distributed windings, flux barriers (63IN) are formed as flux barriers adjacently to each of both ends, in the circumferential direction, of first permanent magnets (62IN) constituting each magnetic pole. Given P1 as the center angle of the arc connecting circumferential-direction centers of slots (51S) adjacent to each other in the circumferential direction, the rotary electric machine is configured to ensure a first condition that center angle θ１with respect to a rotation center O of a first arc portion (61M1) constituting an outer circumferential surface outward in a radial direction of a rotor core (61) in which the flux barrier (63IN) is not formed between the magnetic poles adjacent in the circumferential direction, is θ１= P1 x 2.1 or less. Note that P1 is the center angle of an arc connecting circumferential-direction centers of slots adjacent to each other in the circumferential direction.

Description

Rotating Electric Machine

This application relates to a rotating electric machine.

In rotating electric machines such as motors and generators for EV (Electric Vehicle)/HEV (Hybrid Electric Vehicle), there is a demand for miniaturization, high efficiency, and low NV (Noise Vibration) from the viewpoints of resource conservation, extending the vehicle's driving range, and quietness. To achieve NV reduction, a traction motor as shown below has been disclosed as a rotating electric machine that uses a multi-slot stator structure to suppress magnetic flux fluctuations in the air gap between the stator and rotor, thereby reducing torque ripple, cogging torque, etc.

That is, in a traction motor as a conventional rotating electric machine, a first plurality of magnet pairs are configured in a laminate stack and arranged in a first V-shaped configuration. Also, a second plurality of permanent magnets larger than each of the first plurality of permanent magnets are configured as a second plurality of magnet pairs in the laminate stack and arranged in a second V-shaped configuration. The separation angle of the second magnet pairs is configured to be smaller than the separation angle of the first magnet pairs (see, for example, Patent Document 1).

JP 2020-68654 A (Figs. 3 and 4)

In the above-mentioned conventional traction motor, a method has been proposed in which a multi-slot structure with four slots per pole per phase of the stator is adopted, and the size and arrangement angle of the permanent magnets embedded in the rotor, which is a laminated stack, are adjusted to reduce the cogging torque. However, although such a motor can reduce the cogging torque, it may lead to an increase in stator iron loss and a decrease in motor efficiency. In particular, in a multi-slot structure with a large number of slots per pole per phase, the number of teeth between the magnetic poles of the rotor increases, resulting in a large increase in the aforementioned iron loss and a decrease in motor efficiency.
The present application discloses technology for solving the above-mentioned problems, and aims to provide a highly efficient rotating electric machine even in a multi-slot structure having a large number of slots per pole per phase.

The rotating electric machine disclosed in the present application comprises:
a stator having a plurality of teeth protruding radially inward from an annular yoke portion and an armature winding wound in a plurality of slots formed between the teeth; and a rotor having a rotor core on which a plurality of magnetic poles and flux barriers formed by permanent magnets are formed,
In a rotating electric machine in which 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,
a first flux barrier is formed adjacent to each of both circumferential ends of the first permanent magnet constituting each of the magnetic poles;
A central angle θ1 of a first arc portion constituting a radially outer outer peripheral surface of the rotor core on which the flux barrier is not formed between the magnetic poles adjacent in the circumferential direction is
The first condition is satisfied so that θ1=P1×2.1 or less.
This is what was done.
Here, P1 is the central angle of an arc connecting the circumferential centers of the slots adjacent in the circumferential direction.

The rotating electric machine disclosed in this application provides a highly efficient rotating electric machine even in a multi-slot structure with a large number of slots per pole per phase.

1 is a schematic diagram showing a cross section parallel to an axial direction in a rotating electric machine according to a first embodiment; 1 is a diagram showing a portion of a cross section perpendicular to an axial direction in a rotating electric machine according to a first embodiment; 4 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine of a comparative example. 4 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine of a comparative example. 4 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine of a comparative example. FIG. 13 is a graph showing the iron loss characteristics of a rotating electric machine when the central angle θ1 is changed. 1A and 1B are diagrams for explaining the principle of increase in iron loss in a rotating electric machine; 1 is a diagram showing a portion of a cross section perpendicular to an axial direction in a rotating electric machine according to a first embodiment; 4 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine of a comparative example. 4 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine of a comparative example. 4 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine of a comparative example. FIG. 13 is a graph showing the iron loss characteristics of a rotating electric machine when the central angle θ2 is changed. 1A and 1B are diagrams for explaining the principle of increase in iron loss in a rotating electric machine; FIG. 2 is a graph showing torque characteristics of a rotating electric machine. 1 is a diagram showing a portion of a cross section perpendicular to an axial direction in a rotating electric machine according to a first embodiment; 11 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine according to a second embodiment. FIG. 11 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine according to a second embodiment. FIG. 11 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine according to a second embodiment. FIG. 11 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine according to a second embodiment. FIG. 11 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine according to a second embodiment. FIG. 11 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine according to a second embodiment. FIG. FIG. 2 is a diagram showing magnetomotive force distribution in a rotating electric machine. FIG. 2 is a diagram showing magnetomotive force distribution in a rotating electric machine.

Embodiment 1.
Hereinafter, the rotating electric machine according to the first embodiment will be described with reference to the drawings.
In the figure, the directions in the annular rotating electric machine are indicated as a circumferential direction C, a radial direction X, and an axial direction Y.
FIG. 1 is a schematic diagram showing a cross section parallel to an axial direction Y in a rotating electric machine 100 according to a first embodiment.

As shown in FIG. 1, the rotating electric machine 100 includes a cylindrical housing 70, a stator 50 accommodated therein, and a rotor 60 arranged coaxially with the stator 50 on the radial inside X1 of the stator 50.
The housing 70 has a cylindrical frame 71 with a bottom, and an end plate 72 that closes the opening of the frame 71 .
The stator 50 is fixed to the frame 71 in a fitted state on the radially inner side X1 of the frame 71 .
The rotor 60 is rotatably supported by a rotating shaft 74 provided via a bearing 73 at the center of an end plate 72 of a frame 71 .

2 is a diagram showing a part of a cross section perpendicular to the axial direction of the rotating electric machine 100 according to the embodiment 1. In this figure, only a portion corresponding to about ¼ of the circumference of the annular rotating electric machine 100 is shown.
As shown in FIG. 2 , the stator 50 has a stator core 51 formed by laminating electromagnetic steel sheets, and three-phase coils 55 of U, V, and W as armature windings wound around the stator core 51 .
The stator core 51 has an annular core back 51B, a plurality of teeth 51T extending radially inwardly X1 from the core back 51B, and a plurality of groove-shaped slots 51S formed by being surrounded by adjacent teeth 51T and the core back 51B. Coils 55 are housed in the slots 51S.

In the stator 50 of the present embodiment, 96 slots 51S are formed at equal intervals in the circumferential direction C. If the central angle of an arc 61MS connecting the circumferential centers of circumferentially adjacent slots 51S with respect to the center point O of the rotor 60 is defined as P1, then this central angle P1 is 360°/96=3.75°.
The coils 55 are connected in a distributed winding manner, and the coils 55 in each slot 51S are connected in series or in parallel to each other.

The rotor 60 has an annular rotor core 61 as a rotor core, and permanent magnets 62 (62IN, 62OUT) constituting each magnetic pole formed at set intervals in the circumferential direction of the rotor core 61. The permanent magnets 62 (62IN, 62OUT) are embedded in 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, and four permanent magnets 62 are embedded per pole.
The pair of permanent magnets 62 IN, 62 OUT are each arranged in a V shape so as to expand toward the outer circumferential surface 61 M of the rotor 60 .

In the rotor core 61, flux barriers for preventing leakage of magnetic flux from the permanent magnets 62 are formed adjacent to both ends of the permanent magnets 62. That is, in the permanent magnets 62IN, a flux barrier 63IN is formed as a first flux barrier so as to communicate with both ends of the magnet insertion hole, and in the permanent magnets 62OUT, a flux barrier 63OUT is formed as a second flux barrier so as to communicate with both ends of the magnet insertion hole.
The flux barriers 63IN are formed to extend from both ends of the permanent magnet 62IN in the circumferential direction C toward the radially outward direction X2 at an extension angle θ3 set with respect to the permanent magnet 62IN.

In this embodiment, the number of magnetic poles of rotor 60 is 8, and the number of slots q per pole per phase 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 q per pole per phase, the more slots stator 50 has.
In this manner, in the rotating electric machine 100 having a multi-slot structure, the number of slots 51S that face the outer circumferential surface 61M of the rotor core 61 between adjacent magnetic poles in the circumferential direction C is increased.

Here, as shown in Figure 2, the region of the rotor core 61 between adjacent magnetic poles in the circumferential direction C where no flux barrier is formed near the outer peripheral surface 61M is defined as J1, and the arc that constitutes the outer peripheral surface 61M on the radially outer side X2 of this region J1 is defined as the first arc portion 61M1.
If the central angle of this first arc portion 61M1 with respect to the center of rotation 0 of the rotor 60 is θ1, in this embodiment, the central angle θ1 is configured to ensure the first condition that θ1 = P1 x 2.1 or less.
The vicinity of the outer peripheral surface 61M of the rotor core 61 refers to the area within a set range radially inward X1 from the outer peripheral surface 61M, and this set range is set according to the range in which magnetic flux is short-circuited in the magnetic path from teeth 51T → between magnetic poles → teeth 51T, which will be described later.

Here, the effect of setting the central angle θ1 of the first arc portion 61M1 relative to the center of rotation 0 to be P1×2.1 or less will be explained using the results of an experiment using a motor as a comparative rotating electric machine in which the value of θ1 was changed.
FIG. 3 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine 100EX1 of the comparative example when θ1=P1×0.85.
FIG. 4 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine 100EX2 of the comparative example when θ1=P1×2.08.
FIG. 5 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine 100EX3 of a comparative example when θ1=P1×2.32.
FIG. 6 is a graph showing the iron loss characteristics of a rotating electric machine when the central angle θ1 is changed.
FIG. 7 is a diagram for explaining the principle of increase in iron loss in a rotating electric machine.

For motors for electric vehicles as rotating electric machines, efficiency in the medium speed and low load ranges when driving in urban areas is important, so electromagnetic field analysis was performed under conditions of low current and current phase of 90° using each of the rotating electric machines 100EX1, EX2, EX3 and a rotating electric machine having a value of central angle θ1 other than these rotating electric machines 100EX1, EX2, EX3.
In FIG. 6, the iron loss is normalized under the condition θ1=P1×2.08.

From FIG. 6, it can be seen that the inflection point where the change in iron loss with respect to the central angle θ1 changes sharply is at θ1 = P1 x 2.08. This is because, as the number of slots 51S of the stator 50 facing the first arc portion 61M1 that constitutes the central angle θ1 increases, the magnetic flux that short-circuits in the magnetic path from teeth 51T to between magnetic poles to teeth 51T increases through the area where no flux barrier is formed near the outer circumferential surface 61M of the rotor core 61, as shown by the arrow in FIG. 7, and the magnetic flux density in the teeth 51T increases, leading to an increase in stator iron loss. Therefore, if the central angle θ1 that constitutes the first arc portion 61M1 is configured to ensure the first condition of being set to 2.1 times or less than P1, it is possible to reduce stator iron loss and increase the efficiency of the rotating electric machine.

Here, even if the central angle θ1 is the same between a rotating electric machine with q=2 slots per pole per phase and a rotating electric machine with q=4, the number of slots 51S facing the first arc portion 61M1 is twice as many as that of the rotating electric machine with q=2. Although the effect of suppressing the fluctuation of the magnetic flux in the air gap between the stator and the rotor by increasing the number of slots and reducing the torque ripple and cogging torque can be obtained, the iron loss increases if the number of slots facing the first arc portion 61M1 is large. In particular, if a rotor designed for a stator with q=2 to 3 slots per pole per phase, which is typical for motors for electric vehicles, is applied to a stator with q=4 or more without changing the configuration, there is a high possibility that the iron loss will increase due to the principle described above. In the rotating electric machine of this embodiment, even if it has a multi-slot configuration, the central angle θ1 is designed to ensure the first condition as described above, so that both the quieting effect due to the reduction in torque ripple due to the multi-slot configuration and the high efficiency effect due to the reduction in stator iron loss can be obtained.

Furthermore, the rotating electric machine may have the following configuration.
FIG. 8 is a diagram showing a part of a cross section perpendicular to the axial direction of the rotating electric machine 100A according to the first embodiment, and shows only a portion corresponding to about ¼ of the circumference of the annular rotating electric machine 100A.
In each magnetic pole, the region of the rotor core 61 where no flux barrier is formed near the outer peripheral surface 61M between the flux barrier 63IN and the flux barrier 63OUT is designated as J2, and the arc that constitutes the outer peripheral surface 61M on the radially outer side X2 of this region J2 is defined as the second arc portion 61M2.

The vicinity of the outer peripheral surface 61M of the rotor core 61 refers to the area within a set range radially inward X1 from the outer peripheral surface 61M, and this set range is set according to the range in which magnetic flux is short-circuited in the magnetic path between the magnet layers → the stator 50 → the magnetic poles, as described below.
If the central angle of this second arc portion 61M2 with respect to the center of rotation 0 is θ2, in this embodiment, the central angle θ2 is configured to ensure the first condition that θ2 = P1 × 1.65 or less.

Here, the effect of setting the central angle θ2 of the second arc portion 61M2 relative to the center of rotation 0 to be equal to or less than P1×1.65 will be explained using the results of an experiment using a motor as a comparative rotating electric machine in which the value of θ2 was changed.
FIG. 9 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine 100EX4 of a comparative example when θ2=P1×0.75.
FIG. 10 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine 100EX5 of the comparative example when θ2=P1×1.62.
FIG. 11 is a cross-sectional view perpendicular to the axial direction Y in a rotating electric machine 100EX6 of the comparative example when θ2=P1×2.32.
FIG. 12 is a graph showing the iron loss characteristics of a rotating electric machine when θ2 is changed.
FIG. 13 is a diagram for explaining the principle of increase in iron loss in a rotating electric machine.

As in the case where θ1 was changed, electromagnetic field analysis was performed using each of the rotating electric machines 100EX4, EX5, and EX6 under the condition of low current and current phase of 90°. While the first condition of θ1 being equal to or less than P1×2.1 was ensured, analysis was performed by changing θ2.
In FIG. 12, the iron loss is normalized under the condition θ2=P1×1.62.

From FIG. 12, it can be seen that the iron loss of the motor decreases sharply with respect to the central angle θ2 in the region where the central angle θ2 is equal to or less than P1×1.65. This is because, as the number of slots 51S of the stator 50 facing the second arc portion 61M2 that constitutes the central angle θ2 increases, the magnetic flux that short-circuits between the magnet layers → the stator 50 → the magnetic poles increases, as shown by the arrow in FIG. 13, and the magnetic flux density in the teeth 51T increases, leading to an increase in stator iron loss. Therefore, the first condition is ensured, in which the central angle θ2 that constitutes the second arc portion 61M2 is set to 1.65 times P1 or less. In this way, the magnetic resistance of the above path is increased and the magnetic flux concentrated in a specific tooth of the stator is dispersed, thereby alleviating the local concentration of the magnetic flux density in the teeth, reducing the stator iron loss, and enabling the rotating electric machine to be made more efficient.

The above describes the iron loss characteristics when θ2 is changed. Below, the following describes the torque characteristics when θ2 is changed.
FIG. 14 is a graph showing the torque characteristics of a rotating electrical machine when θ2 is changed while the first condition that θ2 is equal to or less than P1×1.65 is satisfied.
As described above, the magnetic resistance can be increased by reducing the central angle θ2, that is, by shortening the length of the second arc portion 61M2. However, making this central angle θ2 extremely small leads to a decrease in torque as shown in FIG.

Therefore, by configuring the central angle θ2 to satisfy the first condition of θ1 = P1 x 1 or more, but not exceeding P1 x 1.65, it is possible to minimize torque reduction, i.e., to suppress torque reduction to 1% or less compared to a rotating electric machine with a standard configuration of θ2 = P1 x 1.62, while achieving high efficiency in the rotating electric machine.

The rotating electric machine may also be configured as described below.
FIG. 15 is a diagram showing a part of a cross section perpendicular to the axial direction in the rotating electric machine 100B according to the first embodiment.
In the rotating electric machine 100 shown in Figure 2 described above, each magnetic pole has a two-layer structure 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 the second layer.
The rotating electric machine 100B shown in FIG. 15 has a magnetic pole configuration of a total of three layers, including a pair of permanent magnets 62IN as first permanent magnets constituting the first layer, and two further layers of a pair of permanent magnets 62OUT as second permanent magnets.

The effect of forming each magnetic pole in a multi-layered configuration in the radial direction will be described.
In a two-layer configuration in which the magnetic poles are arranged in two radial layers, it is possible to bring the magnetic circuit in the rotor closer to an arrangement along the excitation magnetic flux of the stator. This allows for effective use of reluctance torque, resulting in improved torque. In addition, the two-layer configuration allows for a relatively small number of magnets to be used compared to other multi-layer arrangements that can effectively utilize reluctance torque, which reduces the number of magnets that need to be inserted during rotor manufacturing, leading to reduced manufacturing costs.

However, in the case of a two-layer magnetic pole configuration, the number of magnet layers used is small, so θ1 or θ2 tends to be large. For example, if a rotor designed for 24 slots (q=1), 48 slots (q=2), or 72 slots (q=3) with 8 poles and two-layer magnetic poles (q=4 or less) is used as is for 96 slots (q=4), it is likely to lead to an increase in iron loss due to insufficient consideration given to the value of P1 for θ1 or θ2. In such a configuration, a rotating electric machine 100B as shown in FIG. 15 is effective.
By increasing the number of layers of the magnetic poles from a two-layer structure to a three-layer structure, the degree of freedom in the magnetic pole shape is expanded, making it possible to more effectively utilize the reluctance torque and improving the torque.

Furthermore, the pair of permanent magnets that constitute each layer of the magnetic pole are not limited to a V-shape expanding toward the outer peripheral surface of the rotor, but may be arranged in a flat plate or V-shape, and the shape and number of the magnet insertion holes, and the shape and number of the permanent magnets, are not important.
For example, in a rotor having magnetic poles arranged in a flat plate, between magnetic poles each having only one permanent magnet as a first permanent magnet, the central angle θ1 of the first arc portion constituting the radially outer outer peripheral surface of the rotor core where no flux barrier is formed is configured to ensure the first condition.

Although the 8-pole, 96-slot configuration is shown, the above effects can be obtained even if the number of poles and slots are not limited to this. Also, q is a number equal to or greater than 4, and is not limited to an integer.
Furthermore, since the purpose of the flux barrier is to suppress leakage of magnetic flux, it may be made of a material having a lower relative magnetic permeability than the magnetic steel sheet, such as air or resin.

In addition, because high output is required for motors for electric vehicles, most stator cores are configured with an outer diameter of φ150 to φ300 mm due to the constraints of the vehicle's mounting space and the requirements for torque and power density. When designing a high-output motor with an outer diameter of φ150 mm or more, it is desirable to select a rotor with six or more poles, as explained below.

The optimum split ratio (outer diameter of rotor core/outer diameter of stator core) for high torque and high output design of motors needs to be about 60 to 80%. As the number of poles decreases, the pole pitch (the central angle relative to the arc length of the rotor core per pole) increases, and the amount of magnetic flux flowing through the core back of the stator increases.
To avoid magnetic saturation of the core back, it is necessary to design the core back thicker, but if the number of poles is reduced, the proportion of the motor's radial length that is taken up by the core back thickness increases, making it impossible to ensure a split ratio of 60 to 80%. Therefore, in motors for electric vehicles, a design with fewer than four poles should be avoided, and a configuration with six poles or more is preferable.

In adjusting θ1 to ensure the first condition, for example, the extension angle θ3 of the flux barrier 63IN shown in FIG. 2 may be adjusted, or, as shown in FIG. 2, the end of the flux barrier 63IN on the radially outer side X2 may be formed to extend along the outer peripheral surface 61M of the rotor core 61.

The rotating electric machine of this embodiment configured as described above has:
a stator having a plurality of teeth protruding radially inward from an annular yoke portion and an armature winding wound in a plurality of slots formed between the teeth; and a rotor having a rotor core on which a plurality of magnetic poles and flux barriers formed by permanent magnets are formed,
In a rotating electric machine in which 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,
a first flux barrier is formed adjacent to each of both circumferential ends of the first permanent magnet constituting each of the magnetic poles;
A central angle θ1 of a first arc portion constituting a radially outer outer peripheral surface of the rotor core on which the flux barrier is not formed between the magnetic poles adjacent in the circumferential direction is
The first condition is satisfied so that θ1=P1×2.1 or less.
It is something.
Here, P1 is the central angle of an arc connecting the circumferential centers of the slots adjacent in the circumferential direction.
This makes it possible to provide a highly efficient rotating electric machine even in a multi-slot structure having a large number of slots per pole per phase.

In the rotating electric machine of the present embodiment configured as described above,
The magnetic poles are configured in a plurality of layers by arranging second permanent magnets radially outwardly of the first permanent magnets, the second permanent magnets being adjacent to both ends in a circumferential direction and having second flux barriers formed thereon as the flux barriers,
In each of the magnetic poles, a central angle θ2 of a second arc portion constituting a radially outer outer peripheral surface of the rotor core where the flux barrier is not formed between the first flux barrier and the second flux barrier is
The first condition is ensured so that θ2=P1×1.65 or less.
It is something.
This increases the magnetic resistance between the first permanent magnet and the second permanent magnet → the stator → between the magnetic poles, and disperses the magnetic flux linking the teeth, thereby alleviating local concentration of magnetic flux density and reducing stator iron loss.

In the rotating electric machine of the present embodiment configured as described above,
The central angle θ2 is
The first condition is ensured to be equal to or greater than P1×1.
It is something.
This makes it possible to reduce stator iron loss and suppress a decrease in torque.

In the rotating electric machine of the present embodiment configured as described above,
the first flux barrier is formed so as to extend radially outward from both circumferential ends of the first permanent magnet 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.
It is something.
By adjusting the extension angle θ3 in this manner, it becomes easier to adjust θ1 and θ2 to ensure the first condition.

Embodiment 2.
Hereinafter, the second embodiment of the present invention will be described with reference to the drawings, focusing on the differences from the first embodiment. The same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.
FIG. 16 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine 200 according to the second embodiment, and in this drawing, only a portion corresponding to approximately ¼ of the circumference of the annular rotating electric machine 200 is shown.
FIG. 17 is a partially enlarged cross-sectional view of the rotating electrical machine 200 of FIG. 16, illustrating an example in which the end portion of the flux barrier 63IN on the radially outer side X2 has a different shape.
FIG. 18 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine 200A according to the second embodiment.

In the present embodiment, the rotating

electric machine

200, 200A is provided with a third flux barrier, flux barrier 263M, which is configured independently and not connected to flux barriers 63IN, 63OUT, near the outer circumferential surface 61M of the rotor core 61 between each magnetic pole.

In the rotating electric machine 200 shown in FIG. 16, the first arc portion 61M1 constituting θ1 is defined as the arc length of the rotor core 61 between adjacent flux barriers 63IN between each magnetic pole minus the circumferential length of the flux barrier 263M. In other words, the first arc portion 61M1 in the rotating electric machine 200 of this embodiment is the sum of the arcs 61M1A, 61M1B constituting the outer peripheral surface of the radially outer side X2 of the rotor core 61 where no flux barrier 263M is formed, between the flux barriers 63IN between adjacent magnetic poles in the circumferential direction C.

Furthermore, as in the rotating electric machine 200A shown in FIG. 18, a flux barrier 263M as a third flux barrier may be formed between one side of the flux barrier 63OUT in the circumferential direction C at each magnetic pole and the other side of the flux barrier 63IN in the circumferential direction C.
In this case, the second arc portion constituting θ2 is defined as the arc length of the outer peripheral surface 61M of the rotor core 61 between the flux barrier 63OUT and the flux barrier 63IN minus the circumferential length of the flux barrier 263M, which is the second arc portion 61M2.
That is, in this embodiment, the second arc portion 61M2 is the sum of the arcs 61M2C, 61M2D that constitute the outer peripheral surface of the radially outer side X2 of the rotor core 61 where the flux barrier 263M between the flux barrier 63OUT and the flux barrier 63IN is not formed.

In this way, by arranging the flux barrier 263M with an independent configuration, it is possible to increase the parameters that change the permeance, magnetomotive force, etc. of the rotor, thereby expanding the degree of freedom in design. For example, by adjusting the position, shape, etc., so as to cancel the fluctuation of the exciting magnetic flux of the stator 50, it is possible to reduce the torque ripple.
Furthermore, an extremely large flux barrier increases the stress on the bridge portion 261B shown in Fig. 17 between the flux barrier and the outer circumferential surface 61M of the rotor during high speed rotation, which may reduce the centrifugal force resistance. Even in such a case, by arranging the independently formed flux barrier 263M, the rib 261R shown in Fig. 17 is formed between the flux barriers, so that the stress on the bridge portion 261B can be dispersed to the rib 261R. This contributes to improving the centrifugal force resistance.

In order to prevent deformation of the rotor core 61 due to centrifugal force, it is possible to widen the width in the radial direction X of the bridge portion 261B to relieve stress. However, widening the width of the bridge portion 261B leads to a decrease in torque due to an increase in leakage flux. Therefore, in order to achieve high torque while ensuring centrifugal force resistance, it is necessary to set the width in the radial direction X of the bridge portion 261B as narrow as possible, for example, to 2% or less of the rotor diameter. On the other hand, if the width of the bridge portion 261B is made too narrow, magnetic flux will easily flow into the stator core 51, leading to an increase in stator iron loss, so the width in the radial direction X of the bridge portion 261B may be set to 2% or less of the rotor diameter and further adjusted.

A further modified example in which the position of the flux barrier 263M is adjusted will be described below.
FIG. 19 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine 200B according to the second embodiment.
FIG. 20 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotary electric machine 200C according to the second embodiment.
FIG. 21 is a diagram showing a part of a cross section perpendicular to the axial direction in a rotating electric machine 200D according to the second embodiment.

As shown in FIG. 19, the flux barriers 263M may be disposed both between adjacent flux barriers 63IN in the circumferential direction C and between the flux barriers 63OUT and 63IN at each magnetic pole.

Furthermore, as shown in FIG. 20, in a more effective configuration, the flux barrier 263M may be arranged so that its radially outermost portion X2 is located radially outer than the radially outermost portions X2 of the flux barriers 63IN and 63OUT.
If the distance between the flux barrier 263M and the outer peripheral surface 61M of the rotor core 61 is long, magnetic flux is likely to short-circuit between the flux barrier 263M and the outer peripheral surface 61M, and the function as a flux barrier is reduced. Therefore, by configuring the distance between the flux barrier 263M and the outer peripheral surface 61M of the rotor core 61 to be short, as in the rotating electric machine 200C of Fig. 20, the function as a flux barrier is improved and the effect of reducing iron loss is increased.

Furthermore, as shown in FIG. 21 , a flux barrier 263M may be disposed on the outer circumferential surface 61M side of the rotor core 61 so as to cut out the outer circumferential surface 61M on the radially outer side X2 of the rotor core 61.
In this case as well, the effect of providing the flux barrier 263M described above can be obtained in the same manner.

FIG. 22 is a diagram showing magnetomotive force distribution in a rotating electric machine having a configuration in which the flux barrier 263M is not provided.
FIG. 23 is a diagram showing the magnetomotive force distribution in a rotating electric machine provided with a flux barrier 263M.
As shown in FIGS. 22 and 23, by providing a flux barrier 263M and adjusting its position, it is possible to adjust the magnetomotive force distribution of the rotor 60 to approach a sine wave, thereby reducing torque ripple.

In the rotating electric machine of this embodiment configured as described above,
a third flux barrier formed independently of the first flux barrier and the second flux barrier;
The third flux barrier comprises:
Between one side of the second flux barrier in the circumferential direction and the other side of the first flux barrier in the circumferential direction of each of the magnetic poles, or
Between the magnetic poles adjacent in the circumferential direction, between the first flux barriers adjacent in the circumferential direction,
and
The first arc portion is
is the sum of arcs constituting the outer peripheral surface of the rotor core on the radially outer side where the third flux barrier is not formed between the magnetic poles adjacent in the circumferential direction,
The second arc portion is
a sum of arcs constituting a radially 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,
It is something.
In this way, by providing a third flux barrier and configuring the central angle θ2 to ensure the first condition, it is possible to reduce torque ripple and improve centrifugal force resistance while mitigating local concentration of magnetic flux density in the teeth, thereby reducing stator iron loss and making it possible to increase the efficiency of the rotating electric machine.

In the rotating electric machine of the present embodiment configured as described above,
The third flux barrier comprises:
The arrangement position of the rotor is adjusted so that the magnetomotive force distribution of the rotor approaches a sine wave.
It is something.
This provides a quiet rotating electric machine with reduced torque ripple.

Although the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.
Therefore, countless modifications not illustrated are conceivable within the scope of the technology disclosed in the present application, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

50 Stator, 51 Stator core, 51B Yoke, 51T Teeth, 51S Slot, 61 Rotor core (rotor core), 62IN Permanent magnet (first permanent magnet), 62OUT Permanent magnet (second permanent magnet), 63IN Flux barrier (first flux barrier), 63OUT Flux barrier (second flux barrier), 263M Third flux barrier (flux barrier), 55 Coil (armature winding), 100, 100A, 100B, 200A, 200B, 200C, 200D Rotating motor.

Claims

a stator having a plurality of teeth protruding radially inward from an annular yoke portion and an armature winding wound in a plurality of slots formed between the teeth; and a rotor having a rotor core on which a plurality of magnetic poles and flux barriers formed by permanent magnets are formed,
In a rotating electric machine in which 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,
a first flux barrier is formed adjacent to each of both circumferential ends of the first permanent magnet constituting each of the magnetic poles;
A central angle θ1 of a first arc portion constituting a radially outer outer peripheral surface of the rotor core on which the flux barrier is not formed between the magnetic poles adjacent in the circumferential direction is
The first condition is satisfied so that θ1=P1×2.1 or less.
Rotating electric motor.
Here, P1 is the central angle of an arc connecting the circumferential centers of the slots adjacent in the circumferential direction.
The magnetic poles are configured in a plurality of layers by arranging second permanent magnets radially outwardly of the first permanent magnets, the second permanent magnets being adjacent to both ends in a circumferential direction and having second flux barriers formed thereon as the flux barriers,
In each of the magnetic poles, a central angle θ2 of a second arc portion constituting a radially outer outer peripheral surface of the rotor core where the flux barrier is not formed between the first flux barrier and the second flux barrier is
The first condition is ensured so that θ2=P1×1.65 or less.
The rotating electric machine according to claim 1 .
The central angle θ2 is
The first condition is ensured to be equal to or greater than P1×1.
The rotating electric machine according to claim 2 .
the first flux barrier is formed so as to extend radially outward from both circumferential ends of the first permanent magnet 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.
The rotating electric machine according to claim 2 or 3.
a third flux barrier formed independently of the first flux barrier and the second flux barrier;
The third flux barrier comprises:
Between one side of the second flux barrier in the circumferential direction and the other side of the first flux barrier in the circumferential direction of each of the magnetic poles, or
Between the magnetic poles adjacent in the circumferential direction, between the first flux barriers adjacent in the circumferential direction,
and
The first arc portion is
is the sum of arcs constituting the outer peripheral surface of the rotor core on the radially outer side where the third flux barrier is not formed between the magnetic poles adjacent in the circumferential direction,
The second arc portion is
a sum of arcs constituting a radially 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,
The rotating electric machine according to any one of claims 2 to 4.
The third flux barrier comprises:
The arrangement position of the rotor is adjusted so that the magnetomotive force distribution of the rotor approaches a sine wave.
The rotating electric machine according to claim 5 .
a radially outer portion of the third flux barrier is disposed radially outward of radially outer portions of the first flux barrier and the second flux barrier;
7. The rotating electric machine according to claim 5 or 6.
the third flux barrier is disposed on an outer circumferential surface side of the rotor core so as to cut out a radially outer side of the rotor core;
The rotating electric machine according to any one of claims 5 to 7.
The magnetic pole having a multi-layer structure has a two-layer structure including a first flux barrier constituting a first layer and the second flux barrier constituting a second layer.
The rotating electric machine according to any one of claims 2 to 8.
The magnetic pole having a plurality of layers is configured 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.
The rotating electric machine according to any one of claims 2 to 8.
At least one of the bridge portions formed between the first flux barrier and the outer circumferential surface of the rotor core and the second flux barrier has a radial width that is 2% or less of a diameter of the rotor.
The rotating electric machine according to any one of claims 2 to 10.
The first permanent magnet and the second permanent magnet are configured to have a pair of magnets arranged in a V shape expanding toward the outer circumferential surface side of the rotor.
The rotating electric machine according to any one of claims 2 to 11.
The number of magnetic poles is six or more.
The rotating electric machine according to any one of claims 1 to 12.