WO2021182088A1

WO2021182088A1 - Permanent magnet synchronous motor

Info

Publication number: WO2021182088A1
Application number: PCT/JP2021/006565
Authority: WO
Inventors: 暢孝刈谷
Original assignee: 株式会社ミツバ
Priority date: 2020-03-10
Filing date: 2021-02-22
Publication date: 2021-09-16
Also published as: JP2021145420A

Abstract

The present invention increases a variable magnetic flux width. This permanent magnet synchronous motor is provided with a plurality of permanent magnets in a rotor, wherein: the plurality of permanent magnets are each magnetized in the circumferential direction and disposed so that the magnetization directions are alternately reversed; a rotor core constituting the rotor is provided with a plurality of non-magnetic regions provided corresponding to the plurality of respective permanent magnets; and the plurality of non-magnetic regions are respectively extended in the circumferential direction, adjacently to the plurality of respective permanent magnets, on the side more apart from the stator than the plurality of respective permanent magnets.

Description

Permanent magnet synchronous motor

The present invention relates to a permanent magnet synchronous motor, and particularly to a permanent magnet synchronous motor capable of increasing the variable magnetic flux width.

In a general permanent magnet synchronous motor, the magnetic flux of the magnet interlinks with the stator even when it is not energized, so the induced voltage generated by it hinders the expansion of the high-speed region and the efficiency improvement in the high-speed region. As a motor capable of suppressing such a phenomenon, a variable magnetic flux motor capable of changing the magnetic flux interlinking with the stator has been developed (see, for example, Patent Document 1). In this variable magnetic flux motor, a flux bypass is provided between the permanent magnets adjacent to each other, and the leakage flux can be changed by the q-axis current.

Japanese Unexamined Patent Publication No. 2017-225277

In the above variable magnetic flux motor, there is a problem that the variable magnetic flux width is limited because the strength of the leakage flux passing through the flux bypass is limited.

The present invention has been made to solve the above problem, and an object of the present invention is to increase the variable magnetic flux width.

In order to solve the above problem, one aspect of the present invention is a permanent magnet synchronous motor in which the rotor is provided with a plurality of permanent magnets, and each of the plurality of permanent magnets is magnetized in the circumferential direction and magnetized. The rotor cores that are arranged so that the directions are alternately reversed and constitute the rotor include a plurality of non-magnetic regions provided corresponding to each of the plurality of permanent magnets, and each of the plurality of non-magnetic regions is provided. Provided is a permanent magnet synchronous motor extending in the circumferential direction adjacent to each of the plurality of permanent magnets on a side farther from the stator than each of the plurality of permanent magnets.

According to the present invention, it is possible to increase the variable magnetic flux width.

It is sectional drawing which shows the structure of the permanent magnet synchronous motor of this Example. It is a perspective view which shows the structure of the permanent magnet synchronous motor of this Example. It is an enlarged plan view which shows the structure of the permanent magnet synchronous motor of this Example. It is sectional drawing which shows the example which provides the cover part which covers a permanent magnet from the outside on the outer peripheral surface of a rotor. It is a figure which shows the flow of the magnetic flux at the time of de-energization. It is a figure which shows the flow of the magnetic flux when the d-axis current is passed. It is a figure which shows the flow of the magnetic flux when the d-axis current is passed. It is an enlarged cross-sectional view which shows the structure of the outer rotor type permanent magnet synchronous motor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing the configuration of the permanent magnet synchronous motor of the present embodiment, FIG. 2 is a perspective view showing the configuration of the permanent magnet synchronous motor of the present embodiment, and FIG. 3 is a permanent magnet synchronous motor of the present embodiment. It is an enlarged plan view which shows the structure of.

As shown in FIGS. 1 to 3, the permanent magnet synchronous motors of the present embodiment include a substantially cylindrical stator 10 and a rotor rotatably housed inside the stator 10 about a rotation axis 21 (FIG. 1). 20 and. In the following description, the circumferential direction and the radial direction are defined with reference to the rotation axis 21. Further, the side closer to the rotation axis 21 is defined as "inside", and the side away from the rotation axis 21 is defined as "outside".

The stator 10 includes a stator core 11 in which a plurality of salient poles 12 are formed, and a plurality of coils 13 wound around the salient poles 12, respectively. The salient poles 12 project inward in the radial direction, extend in the direction of the rotation axis 21, and are arranged at regular intervals in the circumferential direction. The stator core 11 is configured by, for example, laminating a plurality of electromagnetic steel sheets in the direction of the rotation axis 21.

The rotor 20 includes a rotor core 23 to which a plurality of (6 in FIGS. 1 and 2) permanent magnets 22 are attached. The rotor core 23 is configured by, for example, laminating a plurality of electromagnetic steel sheets in the direction of the rotation axis 21.

The rotor core 23 is formed from an inner peripheral portion 23a around the rotation axis 21, a plurality of radial portions 26 extending radially from the inner peripheral portion 23a, and radial outer ends of the plurality of radial portions 26. Includes a circumferential portion 23b extending on both sides in the circumferential direction. The permanent magnets 22 are arranged between the circumferential portions 23b adjacent to each other in the circumferential direction.

The permanent magnets 22 extend in the direction of the rotation axis 21 along the outer peripheral surface of the rotor 20 and are arranged at regular intervals in the circumferential direction. Each of the permanent magnets 22 is magnetized in the circumferential direction and is arranged so that the magnetizing directions are alternately reversed. That is, the permanent magnets 22 adjacent to each other in the circumferential direction are arranged so that the north poles or the south poles face each other. A d-axis is formed in the middle of the permanent magnets 22 adjacent to each other in the circumferential direction, that is, in the radial direction passing through the radial portion 26 (FIG. 3).

The rotor core 23 includes a plurality of non-magnetic regions 25 (six in FIGS. 1 and 2) provided corresponding to the plurality of permanent magnets 22, and each of the plurality of non-magnetic regions 25 has a plurality of permanent magnets. On the side (inside) away from each of the stators 10 than each of the magnets 22, the permanent magnets 22 are adjacent to each of the plurality of permanent magnets 22 and extend in the circumferential direction. As a result, a plurality of (6 in FIGS. 1 and 2) leakage flux paths 24 (six in FIGS. 1 and 2) are used to short-circuit the magnetic fluxes of the permanent magnets 22 inside the permanent magnets 22, that is, on the side away from the stator 10. The dotted line in FIG. 1) is formed. Both the leakage flux path 24 and the non-magnetic region 25 extend in the direction of the rotation axis 21. The shape of the leakage flux path 24 is defined according to the shape of the non-magnetic region 25, and the leakage flux path 24 is formed so as to surround the non-magnetic region 25. As shown in FIGS. 1 to 3, the radial portion 26 and the circumferential portion 23b each form a part of the leakage flux path 24.

Although only one leakage flux path 24 is shown in FIG. 1, the other leakage flux paths 24 are similarly formed so as to surround the non-magnetic region 25 corresponding to each of the permanent magnets 22. (See also Figure 3).

As shown in FIGS. 1 to 3, each of the non-magnetic regions 25 is provided symmetrically on both sides in the circumferential direction with respect to each of the permanent magnets 22. That is, the diameter passing through the circumferential center of the non-magnetic region 25 (diameter extending from the rotating axis 21) and the diameter passing through the circumferential center of the corresponding permanent magnet 22 (diameter extending from the rotating axis 21) are the same. There is. Further, the non-magnetic region 25 and the permanent magnet 22 have a line-symmetrical shape with these diameters as the axes of symmetry.

Further, as shown in FIGS. 1 to 3, the length of the non-magnetic region 25 in the circumferential direction is larger than the length of the permanent magnet 22 in the circumferential direction.

Further, the circumferential width of the radial portion 26 (D1 indicated by the arrow in FIG. 3) sandwiched between the non-magnetic regions 25 adjacent to each other in the circumferential direction is the radial width of the permanent magnet 22 (indicated by the arrow in FIG. 3). When the range is 1 to 1.2 times that of D2) shown, it becomes easy to control the strength of the leakage magnetic flux to the leakage magnetic flux path 24 in a wide range. However, the range of the ratio of D1 and D2 is not limited to the range of 1 to 1.2 times. The control of the leakage flux will be described later.

The non-magnetic region 25 can be formed as a void formed in the rotor core 23. When the rotor core 23 is formed by laminating a plurality of electromagnetic steel sheets, a notch corresponding to the non-magnetic region 25 may be formed in the electromagnetic steel sheet.

The non-magnetic region 25 can also be formed of a non-magnetic material. For example, the non-magnetic region 25 can be formed by filling the voids (voids corresponding to the non-magnetic regions 25) formed in the rotor core 23 with a non-magnetic material such as resin. In this case, since the voids formed in the rotor core 23 are filled with resin or the like, the electromagnetic steel plate and the permanent magnet 22 can be reliably fixed due to the adhesiveness of the resin. In addition, the voids in the rotor core 23 are eliminated. Therefore, the robustness of the rotor 20 can be improved.

FIG. 4 is a cross-sectional view showing an example in which a cover portion 30 that covers the permanent magnet 22 from the outside is provided on the outer peripheral surface of the rotor 20. As shown in FIG. 4, by providing the cover portion 30 on the outer peripheral surface of the rotor 20, the permanent magnet 22 can be supported from the outside, so that the permanent magnet 22 can be prevented from falling off to the outside. It is desirable that the cover portion 30 is made of a non-magnetic material. Further, in order to keep the distance between the outer peripheral surface of the rotor core 23 and the inner peripheral surface of the stator core 11 (protrusion pole 12) as small as possible, it is desirable to keep the thickness of the cover portion 30 small.

5 to 5B are diagrams showing the flow of magnetic flux of a permanent magnet, FIG. 5 is a diagram showing the flow of magnetic flux when no power is applied, and FIGS. 5A and 5B are magnetic fluxes when a d-axis current is applied. It is a figure which shows the flow of.

The permanent magnet synchronous motor of this embodiment has a first state in which the magnetic flux of the permanent magnet 22 heads toward the leakage flux path 24 when the d-axis current does not flow, and one of the leakage flux paths 24 when the d-axis current flows. It takes a second state in which the radial portion 26, which is a portion, is magnetically saturated.

When no current (current including d-axis current) is passed through the coil 13, almost all the magnetic flux of the permanent magnet 22 becomes the magnetic flux 100 along the leakage flux path 24, as shown in FIG. Therefore, in this case, almost no magnetic flux is interlinked with the stator 10, and the cogging torque when the stator 10 is not energized becomes extremely small. As a result, high controllability at the time of starting the motor can be obtained. Further, since the induced voltage due to the interlinkage magnetic flux is suppressed, it is possible to expand the high-speed region and improve the efficiency in the high-speed region.

As shown in FIGS. 5A and 5B, when a d-axis current in a direction for strengthening the magnetic flux of the permanent magnet 22 is passed through the corresponding coil 13, the radial portion 26 sandwiched between the non-magnetic regions 25 adjacent to each other in the circumferential direction. (A part of the leakage flux path 24) is saturated by the d-axis current. Therefore, most of the magnetic flux extending in the circumferential direction from the permanent magnet 22 does not go in the inner peripheral direction along the leakage flux path 24, but goes in the outer peripheral direction so as to be bent by 90 ° as shown as the magnetic flux 200. The magnetic flux 200 flows in the stator 10 as an interlinkage magnetic flux through the gap between the stator 10 and the rotor 20. Therefore, in this case, most of the d-axis current and the magnetic flux generated by the permanent magnet 22 become the interlinkage magnetic flux, and the decrease in torque due to the flux flowing into the leakage flux path 24 is suppressed.

As described above, in the permanent magnet synchronous motor of this embodiment, the leakage flux to the leakage flux path 24 can be controlled in a wide range by the d-axis current. That is, the variable magnetic flux width of the leakage flux can be increased. In particular, when the d-axis current is zero or small, including when no power is applied, most of the magnetic flux of the permanent magnet 22 becomes the leakage flux to the leakage flux path 24. Therefore, the strength of the interlinkage magnetic flux can be made extremely small. Further, by passing a d-axis current in the direction of strengthening the magnetic flux of the permanent magnet 22, the ratio of the intensity of the interlinkage magnetic flux to the leakage flux to the leakage flux path 24 can be made extremely large.

As described above, in the permanent magnet synchronous motor of this embodiment, the ratio of the leakage flux and the interlinkage flux to the leakage flux path 24 can be controlled over a wide range and flexibly via the d-axis current. Therefore, it is possible to improve the controllability at low speed, expand the high speed region, and improve the efficiency in the high speed region.

Although the examples of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the examples, and the design and the like within a range not deviating from the gist of the present invention are also included.

For example, in the above embodiment, the inner rotor type permanent magnet synchronous motor in which the rotor is arranged inside the stator has been described, but the present invention is different from the outer rotor type permanent magnet synchronous motor in which the rotor is arranged outside the stator. It is also possible to apply the invention.

FIG. 6 is an enlarged cross-sectional view showing the configuration of an outer rotor type permanent magnet synchronous motor. FIG. 6 shows a cross section in a direction orthogonal to the rotation axis 21.
As shown in FIG. 6, the outer rotor type permanent magnet synchronous motor includes a substantially cylindrical stator 110 and a rotor 120 rotatably housed outside the stator 110 about a rotation axis 21.

The stator 110 includes a stator core 111 in which a plurality of salient poles 112 are formed, and a plurality of coils 113 wound around the salient poles 112, respectively. The salient poles 112 project outward in the radial direction, extend in the direction of the rotation axis 21, and are arranged at regular intervals in the circumferential direction. The stator core 111 is configured by, for example, laminating a plurality of electromagnetic steel sheets in the direction of the rotation axis 21. Note that FIG. 6 illustrates only one salient pole 112.

The rotor 120 includes a rotor core 123 to which a plurality of permanent magnets 122 are attached. The rotor core 123 is configured by, for example, laminating a plurality of electromagnetic steel sheets in the direction of the rotation axis 21. Note that FIG. 6 shows only a part of the permanent magnets 122.

The rotor core 123 extends from the outer peripheral portion 123a, the plurality of radial portions 126 extending in the radial direction from the outer peripheral portion 123a, and the radial inner ends of the plurality of radial portions 126 to both sides in the circumferential direction. Includes the circumferential portion 123b. The permanent magnet 122 is arranged between the circumferential portions 123b adjacent to each other in the circumferential direction.

The permanent magnets 122 are extended in the direction of the rotation axis 21 along the outer peripheral surface of the rotor 120, and are arranged at regular intervals in the circumferential direction. Each of the permanent magnets 122 is magnetized in the circumferential direction and is arranged so that the magnetizing directions are alternately reversed. That is, the permanent magnets 122 that are adjacent to each other in the circumferential direction are arranged so that the north poles or the south poles face each other. A d-axis is formed in the middle of the permanent magnets 122 adjacent to each other in the circumferential direction, that is, in the radial direction passing through the radial portion 126.

The rotor core 123 includes a plurality of non-magnetic regions 125 provided corresponding to each of the plurality of permanent magnets 122, and each of the plurality of non-magnetic regions 125 is farther from the stator 110 than each of the plurality of permanent magnets 122. On the side (outside), it extends in the circumferential direction adjacent to each of the plurality of permanent magnets 122. As a result, a plurality of leakage flux paths 124 (dotted line in FIG. 6) are formed, which are paths for short-circuiting the magnetic fluxes of the permanent magnets 122 on the outside of the permanent magnets 122, that is, on the side away from the stator 110. Both the leakage flux path 124 and the non-magnetic region 125 extend in the direction of the rotation axis 21. The shape of the leakage flux path 124 is defined according to the shape of the non-magnetic region 125, and the leakage flux path 124 is formed so as to surround the non-magnetic region 125. As shown in FIG. 6, the radial portion 126 and the circumferential portion 123b each form a part of the leakage flux path 124.

Also in the permanent magnet synchronous motor shown in FIG. 6, the circumferential width of the radial portion 126 sandwiched between the non-magnetic regions 125 adjacent to each other in the circumferential direction is 1 times to the radial width of the permanent magnet 122. The range can be 1.2 times. In this case, it becomes easy to control the strength of the leakage flux to the leakage flux path 124 in a wide range.

The permanent magnet synchronous motor shown in FIG. 6 has a first state in which the magnetic flux of the permanent magnet 122 heads toward the leakage flux path 124 when the d-axis current does not flow, and one of the leakage flux paths 124 when the d-axis current flows. It takes a second state in which the radial portion 126, which is a portion, is magnetically saturated.

When no current (current including d-axis current) is passed through the coil 113, almost all the magnetic flux of the permanent magnet 122 becomes the magnetic flux along the leakage flux path 124. Therefore, in this case, almost no magnetic flux is interlinked with the stator 110, and the cogging torque when the stator 110 is not energized becomes extremely small. As a result, high controllability at the time of starting the motor can be obtained. Further, since the induced voltage due to the interlinkage magnetic flux is suppressed, it is possible to expand the high-speed region and improve the efficiency in the high-speed region.

When a d-axis current in the direction of increasing the magnetic flux of the permanent magnet 122 is passed through the corresponding coil 113, the radial portion 126 (a part of the leakage flux path 124) sandwiched between the non-magnetic regions 125 adjacent to each other in the circumferential direction is formed. , D-axis current saturates. Therefore, most of the magnetic flux extending in the circumferential direction from the permanent magnet 122 does not go toward the outer peripheral direction along the leakage flux path 124, but goes toward the inner peripheral direction so as to bend by 90 ° as shown as the magnetic flux 200. The magnetic flux 200 flows in the stator 110 as interlinkage magnetic flux through the gap between the stator 110 and the rotor 120. Therefore, in this case, most of the d-axis current and the magnetic flux generated by the permanent magnet 122 become the interlinkage magnetic flux, and the decrease in torque due to the flux flowing into the leakage flux path 124 is suppressed.

As described above, even in the permanent magnet synchronous motor shown in FIG. 6, the leakage flux to the leakage flux path 124 can be controlled in a wide range by the d-axis current. That is, the variable magnetic flux width of the leakage flux can be increased. In particular, when the d-axis current is zero or small, including when no power is applied, most of the magnetic flux of the permanent magnet 122 becomes the leakage flux to the leakage flux path 124. Therefore, the strength of the interlinkage magnetic flux can be made extremely small. Further, by passing a d-axis current in the direction of strengthening the magnetic flux of the permanent magnet 122, the ratio of the intensity of the interlinkage magnetic flux to the leakage flux to the leakage flux path 124 can be made extremely large.

The following additional notes will be further disclosed with respect to the above embodiments of the present invention.

(Appendix 1)
A permanent magnet synchronous motor in which the rotors (20, 120) are provided with a plurality of permanent magnets (22, 122).
Each of the plurality of permanent magnets is magnetized in the circumferential direction and arranged so that the magnetizing directions are alternately reversed.
The rotor cores (23, 123) constituting the rotor are
A plurality of non-magnetic regions (25, 125) provided corresponding to each of the plurality of permanent magnets are provided.
Each of the plurality of non-magnetic regions is a permanent magnet extending in the circumferential direction adjacent to each of the plurality of permanent magnets on a side farther from the stator (10) than each of the plurality of permanent magnets. Synchronous motor.

According to the configuration of Appendix 1, a leakage flux path is formed which is a path for short-circuiting each magnetic flux of the permanent magnet on the side farther from the stator than each of the permanent magnets. By controlling the intensity, the intensity of the magnetic flux interlinking with the stator can be changed.

(Appendix 2)
In the permanent magnet synchronous motor described in Appendix 1,
The non-magnetic region is a permanent magnet synchronous motor composed of a non-magnetic material or voids formed in the rotor core.

According to the configuration of Appendix 2, the leakage flux path can be defined according to the range of the non-magnetic region composed of the non-magnetic material or the voids formed in the rotor core. When the non-magnetic region is made of a non-magnetic material, the robustness of the rotor can be obtained.

(Appendix 3)
In the permanent magnet synchronous motor described in Appendix 1 or Appendix 2,
A permanent magnet synchronous motor in which each of the non-magnetic regions and each of the permanent magnets are line-symmetrical with respect to a common axis of symmetry extending in the radial direction.

According to the configuration of Appendix 3, since the non-magnetic region is provided symmetrically on both sides in the circumferential direction with respect to the permanent magnet, the same effect is obtained with respect to the control of the magnetic flux interlinking with the stator regardless of the rotation direction of the rotor. Can be obtained.

(Appendix 4)
In the permanent magnet synchronous motor according to any one of Appendix 1 to Appendix 3,
A permanent magnet synchronous motor in which the length of the non-magnetic region in the circumferential direction is larger than the length of each of the permanent magnets in the circumferential direction.

According to the configuration of Appendix 4, since the length of the non-magnetic region in the circumferential direction is larger than the length of the permanent magnet in the circumferential direction, the position where the leakage flux path is formed can be appropriately defined.

(Appendix 5)
In the permanent magnet synchronous motor according to any one of Supplementary notes 1 to 4.
The rotor core
The inner peripheral part (23a) around the rotation axis (21) and
A plurality of radial portions (26) extending in the radial direction from the inner peripheral portion, and
Includes a circumferential portion (23b) extending from each radial outer end of each of the plurality of radial portions to both sides in the circumferential direction.
The permanent magnets are arranged between the circumferential portions adjacent to each other in the circumferential direction.
The non-magnetic region is a permanent magnet synchronous motor arranged between the radial portions adjacent to each other in the circumferential direction.

According to the configuration of Appendix 5, the leakage flux path is formed so as to pass through the circumferential portion and the radial portion.

(Appendix 5A)
In the permanent magnet synchronous motor according to any one of Supplementary notes 1 to 4.
The rotor core
The outer peripheral portion (123a) around the rotation axis (21) and
A plurality of radial portions (126) extending in the radial direction from the outer peripheral portion, and
Includes a circumferential portion (123b) extending from each radial inner end of each of the plurality of radial portions to both sides in the circumferential direction.
The permanent magnets are arranged between the circumferential portions adjacent to each other in the circumferential direction.
The non-magnetic region is a permanent magnet synchronous motor arranged between the radial portions adjacent to each other in the circumferential direction.

According to the configuration of Appendix 5A, in the outer rotor type permanent magnet synchronous motor, a leakage flux path is formed so as to pass through the circumferential portion and the radial portion. In the configuration of Appendix 5A, the circumferential width of the radial portion sandwiched between the non-magnetic regions adjacent to each other in the circumferential direction is in the range of 1 to 1.2 times the radial width of the permanent magnet. be able to. In this case, it becomes easy to control the strength of the leakage flux to the leakage flux path in a wide range.

(Appendix 6)
In the permanent magnet synchronous motor described in Appendix 5,
The circumferential width of the radial portion sandwiched between the non-magnetic regions adjacent to each other in the circumferential direction is in the range of 1 to 1.2 times the radial width of the permanent magnet. Synchronous motor.

According to the configuration of Appendix 6, the circumferential width of the radial portion is in the range of 1 to 1.2 times the radial width of the permanent magnet, so that the radial width in which the leakage flux path is formed is formed. The width of the part in the circumferential direction can be appropriately defined, and the strength of the leakage flux to the leakage flux path can be easily controlled in a wide range.

(Appendix 7)
In the permanent magnet synchronous motor according to any one of Appendix 1 to Appendix 6,
The rotor is arranged inside the stator and
The rotor is a permanent magnet synchronous motor including a cover portion that covers the permanent magnet from the outside.

According to the configuration of Appendix 7, the cover portion can prevent the rotor from falling off to the outside.

(Appendix 8)
The permanent magnet synchronous motor according to any one of claims 1 to 6.
Leakage flux paths (24, 124) that short-circuit the magnetic fluxes of the permanent magnets are formed in the rotor core.
The leakage flux paths are formed so as to surround a non-magnetic region on a side away from each of the permanent magnets.
The permanent magnet synchronous motor is
The first state in which the magnetic flux of the permanent magnet goes toward the leakage flux path when the d-axis current is not passed,
A second state in which at least a part of the leakage flux path is magnetically saturated when the d-axis current is passed.
Take, permanent magnet synchronous motor.

According to the configuration of Appendix 8, the permanent magnet synchronous motor takes a first state in which the magnetic flux of the permanent magnet goes toward the leakage flux path and a second state in which at least a part of the leakage flux path is magnetically saturated. Therefore, the strength of the magnetic flux interlinking with the stator can be controlled in a wide range.

10, 110

Stator

20, 120 Rotor 21

Rotating axis

22, 122

Permanent magnet

23, 123

Rotor core

24, 124

Leakage flux path

25, 125

Non-magnetic region

26, 126 Radial part 30 Cover

Claims

A permanent magnet synchronous motor equipped with multiple permanent magnets in the rotor.
Each of the plurality of permanent magnets is magnetized in the circumferential direction and arranged so that the magnetizing directions are alternately reversed.
The rotor core constituting the rotor is
It is provided with a plurality of non-magnetic regions provided corresponding to each of the plurality of permanent magnets.
A permanent magnet synchronous motor in which each of the plurality of non-magnetic regions extends in the circumferential direction adjacent to each of the plurality of permanent magnets on a side farther from the stator than each of the plurality of permanent magnets.
In the permanent magnet synchronous motor according to claim 1.
A permanent magnet synchronous motor in which the non-magnetic region is composed of a non-magnetic material or voids formed in the rotor core.
In the permanent magnet synchronous motor according to claim 1 or 2.
A permanent magnet synchronous motor in which each of the non-magnetic regions and each of the permanent magnets are line-symmetrical with respect to a common axis of symmetry extending in the radial direction.
In the permanent magnet synchronous motor according to any one of claims 1 to 3.
A permanent magnet synchronous motor in which the length of the non-magnetic region in the circumferential direction is larger than the length of each of the permanent magnets in the circumferential direction.
In the permanent magnet synchronous motor according to any one of claims 1 to 4.
The rotor core
The inner circumference around the axis of rotation and
A plurality of radial parts extending in the radial direction from the inner peripheral part,
Includes a circumferential portion extending from each radial outer end of each of the plurality of radial portions to both sides in the circumferential direction.
The permanent magnets are arranged between the circumferential portions adjacent to each other in the circumferential direction.
The non-magnetic region is a permanent magnet synchronous motor arranged between the radial portions adjacent to each other in the circumferential direction.
In the permanent magnet synchronous motor according to claim 5.
The circumferential width of the radial portion sandwiched between the non-magnetic regions adjacent to each other in the circumferential direction is in the range of 1 to 1.2 times the radial width of the permanent magnet. Synchronous motor.
The permanent magnet synchronous motor according to any one of claims 1 to 6.
The rotor is arranged inside the stator and
The rotor is a permanent magnet synchronous motor including a cover portion that covers the permanent magnet from the outside.
The permanent magnet synchronous motor according to any one of claims 1 to 6.
A leakage flux path for short-circuiting the magnetic fluxes of the permanent magnets is formed in the rotor core.
The leakage flux path is formed so as to surround the non-magnetic region on a side away from each of the permanent magnets.
The permanent magnet synchronous motor is
The first state in which the magnetic flux of the permanent magnet goes toward the leakage flux path when the d-axis current is not passed,
A second state in which at least a part of the leakage flux path is magnetically saturated when the d-axis current is passed.
Take, permanent magnet synchronous motor.