JP2016067138A - Dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase efficiency of a dynamo-electric machine.SOLUTION: A power converter includes a rotor 10, and a stator where a three-phase winding is wound on the outer periphery of the rotor 10 so as to surround it via a gap. The rotor 10 has a plurality of permanent magnets 14 provided in the circumferential direction of the rotor 10 at intervals, and a plurality of iron core pieces 12 provided in the circumferential direction of the rotor 10 between the permanent magnets 14, respectively. The permanent magnets 14 are magnetized in a direction perpendicular to the radial direction of the rotor 10, magnetization directions of adjacent permanent magnets 14 are opposite to each other, each iron core piece 12 is provided with a high magnetic resistance portion at the circumferential center on the radial outside, so that the magnetic flux is hard to pass through this portion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotating electrical machine having a rotor divided in a circumferential direction.

  2. Description of the Related Art Conventionally, in a rotary electric machine including a permanent magnet, a spoke-arranged permanent magnet type rotor that easily concentrates the magnetic flux of the permanent magnet and achieves high output is known.

  For example, Non-Patent Document 1 describes that a short circuit of magnetic flux is reduced by paying attention to d-axis and q-axis magnetic paths.

  In Patent Document 1, a directional magnetic material is provided so that the magnetic flux of a permanent magnet is concentrated at the center of the rotor magnetic pole, and the rotor core is divided at the center of the magnetic pole.

JP 2012-165576 A

Mitsuhiko Sato et al. “Examination of spoke type IPM motor for compressor of air conditioner considering productivity”, 2013 IEEJ Industrial Application Conference, 3-10, III-107-110

  In Non-Patent Document 1, since the outer peripheral portion of the iron core is short-circuited, it cannot be said that the short-circuit of the magnetic flux has been sufficiently reduced. Further, in order to maximize the reluctance torque, it is necessary to increase the difference between the d-axis inductance and the q-axis inductance (Lq >> Ld), but no consideration is given to this.

  In Patent Document 1, it is possible to increase the rotational force using the magnetic flux of the permanent magnet, but it is not possible to use the reluctance torque, and to make the permanent magnet stronger in order to further increase the torque. There is a need.

  In addition, in these spoke-arranged permanent magnet type rotors, in order to increase the torque, the mainstream is to concentrate the magnetic flux of the permanent magnet on the magnetic pole, but this increases the counter electromotive force of the rotating electrical machine, It is necessary to increase the withstand voltage of the switch element for controlling the current flowing through the capacitor.

  The present invention includes a rotor, and a stator wound with a three-phase winding that surrounds the outer periphery of the rotor via a gap, and the rotor is spaced apart from each other in the circumferential direction of the rotor. A plurality of permanent magnets, and a plurality of core pieces provided between the permanent magnets in the circumferential direction of the rotor and having magnetic poles formed on the outer peripheral side, the permanent magnets rotating Magnetized in a direction perpendicular to the radial direction of the child, the magnetization directions of the adjacent permanent magnets are opposite to each other, and each core piece has a high magnetoresistance in the circumferentially central portion and the radially outer portion. A part is provided, and it is difficult for magnetic flux to pass through this part.

  Each core piece may have a groove directed from the outer peripheral side toward the inner side in the central portion in the circumferential direction.

  It is preferable that an additional permanent magnet is disposed inside the groove from the outer peripheral side of the center portion in the circumferential direction toward the inside in each iron core piece.

  Each core piece may have a flux barrier groove extending in an arc shape from a pair of circumferential outer peripheral side intermediate portions toward a radially inner side and a circumferential central portion.

  In each iron core piece, an additional permanent magnet may be disposed in a flux barrier groove extending in an arc shape from a pair of circumferential outer peripheral side portions toward the radially inner side and the circumferential central portion.

  A rod-like support member that penetrates each iron core piece in the rotation axis direction may be provided, and both ends of the support member may be fixed by a pair of brackets arranged on both sides of the rotor.

  The support member may be formed of a nonmagnetic material.

  ADVANTAGE OF THE INVENTION According to this invention, the short circuit of the magnetic flux in the circumferential direction center part and radial direction outer part of a rotor can be prevented, and the efficiency of a rotary electric machine can be raised.

It is a figure which shows the structure of a rotary electric machine. It is a figure which shows the structure of a rotor. It is a figure which shows the structure of a rotor. It is a figure which shows the structure of the iron core piece of 1st embodiment. It is a figure which shows the state of the magnetic flux of the iron core piece of 1st embodiment. It is a figure which shows the structure of the iron core piece of 2nd embodiment. It is a figure which shows the state of the magnetic flux of the iron core piece of 2nd embodiment. It is a figure which shows the structure of the iron core piece of 3rd embodiment. It is a figure which shows the state of the magnetic flux of the iron core piece of 3rd embodiment. It is a figure which shows the state of the magnetic flux of the iron core piece of 1st embodiment of 4th embodiment. It is a figure which shows the state of the magnetic flux of the iron core piece of 4th embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described herein.

"overall structure"
As shown in FIG. 1, the rotating electrical machine 1 includes a rotor 10 and a stator 20 that surrounds the rotor 10 with a predetermined gap. The stator 20 includes an annular yoke 22, a tooth 24 extending radially inward from the yoke 22, and a stator winding 26 wound around the tooth 24. The yoke and the teeth function as a stator core. The stator winding 26 is a three-phase winding, for example, a distributed winding. Then, alternating currents that are 120 degrees out of phase with each other are supplied to the three-phase stator windings 26, thereby forming a rotating magnetic field and rotating the rotor 10.

  FIG. 2 shows a schematic configuration (cross section viewed from the axial direction) of the spoke-arranged permanent magnet type rotor according to the first embodiment, and FIG. 3 shows an X-X ′ cross section in FIG. 1. In FIG. 2, the shaft is not shown.

  Thus, the rotor 10 has an annular shape as a whole. An arc-shaped iron core piece 12 is combined in a plurality of circumferential directions via a quadrangular columnar permanent magnet 14. In this example, there are eight iron core pieces 12 and permanent magnets 14, and there are eight magnetic poles. The permanent magnets are magnetized in a direction (substantially in the circumferential direction) perpendicular to the radial direction, and the eight magnets are adjacent to each other and the NS arrangement is reversed. When the top of the rotor 10 is 0 °, 22.5 °, 67.5 °, 112.5 °, 157.5 °, 202.5 °, 247.5 °, 292.5 °, The permanent magnet 14 is located at a position of 337.5 °. In the clockwise direction, odd-numbered permanent magnets 14 have N poles on the right side and S poles on the left side, and even-numbered permanent magnets 14 have N poles on the right side and S poles on the left side. In addition, the arrow in a figure has shown the direction of magnetic flux.

  The permanent magnet 14 has a shorter length in the radial direction than the core piece 12 (thickness is smaller), and is in contact with the radially inner portion of the circumferential side surface of the core piece 12. Therefore, the iron core piece 12 sandwiched between the first and second permanent magnets 14 has an S pole on the radially inner side and an N pole on the outer peripheral side due to the N poles of the permanent magnets 14 on both sides. Since the magnetization directions of the permanent magnets 14 are sequentially reversed, the iron core pieces 12 arranged in the clockwise direction thereafter have S and N poles on the outer peripheral side.

  In such a rotor 10, a rod-like support member 16 is disposed so as to penetrate the iron core piece 12. Then, as shown in FIG. 3, both ends of the support member 16 are fixed to a pair of disk-shaped brackets 18, whereby the core piece 12 and the permanent magnet 14 are clamped and fixed in the axial direction. Moreover, since the support member 16 penetrates the inside of the iron core piece 12 and extends in the axial direction, the iron core piece 12 and the permanent magnet 14 can be prevented from jumping out by centrifugal force. A shaft 30 extending in the axial direction is disposed at the center of the rotor 10, and the brackets 18 and 18 are fixed to the shaft 30.

<First embodiment>
The configuration of the spoke-arranged permanent magnet rotor according to the first embodiment will be described with reference to FIG. The iron core piece 12 has a circular arc shape as a whole, and the inner peripheral surface is a surface having no irregularities. In addition, the rotor 10 is cylindrical as a whole as shown in FIG. 3, and the iron core piece 12 extends in the axial direction.

  On both side surfaces of the iron core piece 12 in the circumferential direction, stepped portions having recessed inner portions in the radial direction are formed. A side portion of the permanent magnet 14 is engaged with the step portion. That is, both side portions of the permanent magnet 14 are in contact with the core piece 12 in the circumferential direction, and the radially outer side is held by the stepped portion of the core piece 12. The outer portions in the radial direction on both sides in the circumferential direction of the core pieces 12 project on the permanent magnet 14, but a space is provided between the side surfaces of the adjacent core pieces 12.

  A slit-like groove 42 is formed in the center portion in the circumferential direction of the core piece 12 from the outer peripheral portion toward the inside in the radial direction. The groove 42 extends in the axial direction. Due to the groove 42, the magnetic resistance of the radially outer portion of the central portion in the circumferential direction of the iron core piece 12 is larger than the others.

  Further, on the outer peripheral side of the core piece 12, grooves 44 extending radially inward from the outer peripheral side are formed in a pair of intermediate portions on both sides of the groove 42. The groove 44 has a radially inner terminal portion having a circular cross section (cylindrical slit extending in the axial direction), and the support member 16 is inserted through this portion.

  Therefore, when the rotor 10 rotates, the permanent magnet 14 receives the centrifugal force directed outward in the radial direction by the step portion of the iron core piece 12, and the iron core piece 12 is held against the centrifugal force by the support member 16. .

  In addition, since the iron core piece 12 constitutes one magnetic pole, the d axis is located at the center in the circumferential direction, and the q axis is located between the adjacent iron core pieces 12.

  FIGS. 5A to 5C show magnetic flux diagrams of the d-axis magnetic path, the q-axis magnetic path, and the permanent magnet in the iron core piece 12 (outer peripheral S pole) of FIG. The d-axis magnetic flux and the permanent magnet magnetic flux have magnetic paths that circulate around the groove 44 at two portions separated by the central groove 42. On the other hand, the q-axis magnetic flux forms a magnetic path that passes through the inside of the central groove 42 and connects both sides thereof, and is separated from the magnetic path of the d-axis magnetic flux. It can also be seen that the q-axis magnetic path flux diagram has a larger number of magnetic fluxes and the q-axis inductance is larger than the d-axis inductance compared to the d-axis magnetic path flux diagram. Moreover, when the magnetic flux diagram of a permanent magnet is confirmed, it turns out that sufficient magnetic flux number is obtained.

  As described above, in this embodiment, the groove 42 from the outer peripheral side is formed so as to match the d-axis of the iron core piece 12, and the groove is also formed at a position located between the center of the d-axis magnetic path and the center of the q-axis magnetic path. 44 is formed. Therefore, the grooves 42 and 44 reduce only the d-axis inductance without reducing the q-axis inductance, reduce the interference of the d-axis magnetic path with respect to the q-axis magnetic path, and efficiently generate reluctance torque. can do.

  The support member 16 is made of a nonmagnetic material such as aluminum, titanium, ceramic, or resin material. As a result, the magnetic resistance of this portion can be increased, and the magnetic path can be made appropriate.

<Second embodiment>
In the second embodiment, the iron core shape of the conventional embedded class A magnet type rotor is applied to the spoke-arranged permanent magnet type rotor.

  That is, the rotor 10 of 2nd embodiment forms the groove | channel arrangement | positioning of the iron core piece 12 as an arc-shaped flux barrier type | mold, as FIG. 6 shows. The groove arrangement may be a V-shaped flux barrier type.

  An axial groove 50 is formed at the center in the circumferential direction of the iron core piece 12 and has a semicircular cross section from the outer periphery. Then, a little apart from the groove 50 in the radial direction, an arc-shaped groove 52 is formed from the outer diameter side of both side portions of the groove 50 leaving the central portion. The pair of grooves 52 form an arc-shaped flux barrier. And the supporting member 16 is arrange | positioned in the intermediate part of each groove | channel 52. FIG.

  7A to 7C show magnetic flux diagrams of the d-axis magnetic path, the q-axis magnetic path, and the permanent magnet in the iron core piece 12 (outer peripheral side S pole) in FIG. The d-axis magnetic flux and the permanent magnet magnetic flux flow in the radially inner portion and the outer portion of the pair of grooves 52 that form the flux barrier, and also flow in the radially central portion that connects them.

  On the other hand, the q-axis magnetic flux flows independently in the radially inner portion and the outer portion separated by the groove 52, and does not flow in the radially central portion connecting these. Thus, it can be seen that an effective magnetic path can be formed separately from the q-axis magnetic flux magnetic path and the d-axis magnetic flux magnetic path.

<Third embodiment>
In 3rd embodiment, the additional permanent magnet 60 is arrange | positioned in the center part of the d-axis center magnetic pole of the iron core piece 12 of 1st embodiment.

  In the example of FIG. 8, the outer periphery of the iron core piece 12 is S, and the additional permanent magnet 60 has the south pole in the radial direction together with other magnetic fluxes.

  9A to 9C show magnetic flux diagrams of the d-axis magnetic path, the q-axis magnetic path, and the permanent magnet in the iron core piece 12 (outer peripheral side S pole) in FIG. The d-axis magnetic flux and the permanent magnet magnetic flux flow in the radially inner portion and the outer portion of the pair of grooves 52 that form the flux barrier, and also flow in the radially central portion that connects them.

  An additional permanent magnet 60 is arranged in the center of the d-axis in a direction in which it is magnetized and oriented in the radial direction. In this example, the plate-shaped additional permanent magnet 60 is arranged so that the inner side becomes the north pole. As a result, the permanent magnet 14 can further strengthen the inside of the iron core piece 12 being an N pole.

  Accordingly, higher torque can be achieved, and high torque power can be secured at a low rotational speed.

<Fourth embodiment>
In the fourth embodiment, as shown in FIG. 10, an additional pair of permanent magnets 60 on the d-axis central magnetic pole side of the pair of grooves 52 forming the flux barrier in the arc shape of the rotor core piece of the second embodiment. Place.

  Thereby, the magnetic flux by the permanent magnet 14 is strengthened, and it becomes possible to ensure high torque power at a low rotational speed. That is, as shown in FIG. 11, the additional permanent magnet 60 can reinforce the magnetic flux of the permanent magnet 14.

<Effect of embodiment>
According to this embodiment, the d-axis magnetic path and the q-axis magnetic path can be efficiently separated. By efficiently separating the d-axis magnetic path and the q-axis magnetic path, the q-axis inductance becomes larger than the d-axis inductance, and a sufficient number of magnetic fluxes can be obtained for the magnetic flux of the permanent magnet.

  As a result, reluctance torque can be obtained without impairing the torque generated by the permanent magnet, and a high-torque, high-output, low-cost rotating electric machine can be provided without increasing the counter electromotive force of the rotating electric machine. It becomes.

DESCRIPTION OF SYMBOLS 1 Rotating electrical machine, 10 Rotor, 12 Iron core piece, 14 Permanent magnet, 16 Support member, 18 Bracket, 20 Stator, 22 York, 24 Teeth, 26 Stator winding, 30 Shaft, 42, 44, 50, 52 Groove 60 Additional permanent magnets.

Claims (7)

A rotor,
A stator wound with a three-phase winding that surrounds the outer periphery of the rotor via a gap;
With
The rotor is
A plurality of permanent magnets spaced apart from each other in the circumferential direction of the rotor;
A plurality of core pieces each provided between the permanent magnets in the circumferential direction of the rotor and having magnetic poles formed on the outer peripheral side;
The permanent magnet is
Magnetized in a direction perpendicular to the radial direction of the rotor, the magnetization directions of adjacent permanent magnets are opposite to each other,
Each core piece is a central portion in the circumferential direction and a high magnetic resistance portion is provided in a radially outer portion, and it is difficult for magnetic flux to pass through this portion.
Rotating electric machine. The rotating electrical machine according to claim 1,
Each core piece has a groove directed from the outer peripheral side to the inner side in the central portion in the circumferential direction.
Rotating electric machine. The rotating electrical machine according to claim 2,
In each iron core piece, an additional permanent magnet is arranged inside the groove directed from the outer peripheral side of the central portion in the circumferential direction toward the inside.
Rotating electric machine. The rotating electrical machine according to claim 1,
Each core piece has a flux barrier type groove extending in a circular arc shape from a pair of outer peripheral side intermediate portions in the circumferential direction toward the radially inner side and the central portion in the circumferential direction.
Rotating electric machine. The rotating electrical machine according to claim 4,
In each iron core piece, an additional permanent magnet is disposed in a flux barrier type groove extending in an arc shape from a pair of outer peripheral side intermediate portions in the circumferential direction toward the radially inner side and the circumferential central portion.
Rotating electric machine. A rotating electrical machine according to any one of claims 1 to 5,
A rod-like support member that penetrates each iron core piece in the direction of the rotation axis is provided, and both ends of the support member are fixed by a pair of brackets arranged on both sides of the rotor.
Rotating electric machine. In the rotating electrical machine according to claim 6,
The support member is formed of a non-magnetic material;
Rotating electric machine.