JP2014161205A - Interior magnet type rotating electrical machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interior magnet type rotating electrical machine that suppresses cogging torque without reducing torque.SOLUTION: An interior permanent magnet type magnet rotor 20 has a cylindrical shape and has flat permanent magnets 40 embedded perpendicularly to a d axis, and a stator 100 is arranged on an outer circumference side of the interior permanent magnet type magnet rotor 20 and has circumferentially juxtaposed teeth 103 wound with coils 104 on an inner circumference side. The interior permanent magnet type magnet rotor has four first grooves 33-36 per pole symmetric with respect to the d axis on a peripheral side of the permanent magnet 40 in an outer circumferential surface, and has two second grooves 37, 38 per pole symmetric with respect to the d axis in regions beyond the peripheral side of the permanent magnet 40. θ1≥θ2 is satisfied, where θ1 is an angle formed by two center grooves 33, 34 nearer to the middle of the four first grooves 33-36 and θ2 is an angle formed by the outer grooves 35, 36 and the adjacent center grooves 33, 34 of the four first grooves 33-36.

Description

  The present invention relates to a magnet-embedded rotating electrical machine.

  In a magnet-embedded rotating electrical machine, grooves are formed obliquely in the vicinity of the magnetic pole boundary on the outer periphery of the rotor in order to reduce cogging torque (for example, Patent Document 1).

JP 2001-231196 A

  By the way, there are two types of motor torque, magnet torque and reluctance torque. If a groove is provided on the surface of the q-axis rotor, the magnetic flux path that generates reluctance torque is obstructed, and the torque is reduced. Therefore, if it is intended to reduce the cogging torque by providing a groove on the surface of the q-axis rotor, the torque will decrease due to the decrease in reluctance torque.

  An object of the present invention is to provide a magnet-embedded rotating electrical machine that can suppress cogging torque without causing a reduction in torque.

  In the first aspect of the present invention, the permanent magnet embedded magnet rotor has a cylindrical shape and a flat permanent magnet embedded perpendicularly to the d axis, and is disposed on the outer peripheral side of the permanent magnet embedded magnet rotor. And a stator embedded with teeth around which coils are wound on the inner periphery side in parallel with the outer periphery of the permanent magnet embedded magnet rotor via a gap. In the embedded rotary electric machine, four first grooves per pole are provided symmetrically with respect to the d axis on the outer peripheral side of the permanent magnet on the outer peripheral surface of the permanent magnet embedded magnet rotor, and the permanent magnet embedded magnet Two second grooves per pole are provided symmetrically with respect to the d-axis in a region not on the outer peripheral side of the permanent magnet on the outer peripheral surface of the rotor, and an angle formed by two center grooves closer to the center of the four first grooves Θ1, outside of the four first grooves When the angle of the center groove adjacent to the groove and .theta.2, and summarized in that has a .theta.1 ≧ .theta.2.

  According to the first aspect of the present invention, four first grooves per pole are provided symmetrically with respect to the d axis on the outer peripheral side of the permanent magnet on the outer peripheral surface of the permanent magnet embedded magnet rotor, and the permanent magnet embedded The angle formed by the two center grooves closer to the center of the four first grooves is provided in a region on the outer peripheral surface of the permanent magnet rotor that is not on the outer peripheral side of the permanent magnet, symmetrically with respect to the d axis. Is θ1, and the angle formed by the center groove adjacent to the outer groove of the four first grooves is θ2, θ1 ≧ θ2, so that the magnetic flux density distribution on the surface of the rotor is made closer to a sinusoidal shape. Can suppress the cogging torque. As a result, the cogging torque can be suppressed without causing a reduction in torque.

As described in claim 2, in the magnet-embedded rotary electric machine according to claim 1, it is preferable that θ1> θ2.
As described in claim 3, in the magnet-embedded rotary electric machine according to claim 1 or 2, the θ1 is 40 ± 1 ° in electrical angle, and the θ2 is 24 ± 1 in electrical angle. It should be °.

  As described in claim 4, in the magnet-embedded rotating electrical machine according to any one of claims 1 to 3, the second groove adjacent to the outer groove of the four first grooves. When the angle formed is θ3, it is preferable that θ2 = θ3.

  As described in claim 5, in the magnet-embedded rotary electric machine according to any one of claims 1 to 4, the θ1 may be three times or more the opening angle of the tip of the tooth.

  According to the present invention, the cogging torque can be suppressed without causing a reduction in torque.

The schematic diagram of the rotary electric machine in embodiment. The partial expansion schematic diagram of a rotary electric machine. The partial expansion schematic diagram of a rotary electric machine. The schematic diagram of a rotor. (A) is a figure which shows the measurement result of maximum torque, (b) is a figure which shows the measurement result of cogging torque. The figure which shows the measurement result of cogging torque. The figure which shows the measurement result of cogging torque. The figure which shows the measurement result of cogging torque.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the magnet-embedded rotary electric machine 10 includes a permanent magnet embedded magnet rotor (rotor) 20 and a stator (stator) 100. A stator 100 is disposed on the outer peripheral side of a cylindrical permanent magnet embedded magnet rotor 20. The inner peripheral surface of the stator 100 faces the outer peripheral surface of the permanent magnet embedded magnet rotor 20 via a gap G (see FIG. 2). Each figure is a schematic diagram, and the shape is emphasized. The magnet-embedded rotating electrical machine 10 has “8” poles.

  As shown in FIGS. 1 and 2, in the stator 100, the stator core 101 has a cylindrical shape, and a plurality (48) of slots 102 are formed in the circumferential direction inside the stator core 101. Each slot 102 opens to the inner peripheral surface. Teeth 103 are formed between the slots 102. In the stator 100, the number of slots per pole is “6” (the number of teeth per pole is “6”), and the angle from the center O per pole is 45 °. A coil (winding) 104 through which a three-phase alternating current is energized is wound around the teeth 103 provided at equal intervals. As described above, the stator 100 includes the teeth 103 around which the coil 104 is wound on the inner peripheral side in parallel in the circumferential direction.

  A permanent magnet embedded magnet rotor 20 is disposed inside the stator 100, and the rotor 20 is a permanent magnet embedded magnet rotor core 30 in which a plurality of (for example, several tens) electromagnetic disk-shaped steel plates are stacked. The shaft 50 is inserted through the center of the rotor core 30. The embedded permanent magnet magnet rotor 20 is rotatably supported by a bearing of a housing (not shown) via a shaft 50 with the outer peripheral surface of the rotor core 30 spaced apart from the teeth 103.

  A permanent magnet embedded hole 31 is formed in the permanent magnet embedded magnet rotor core 30, and the permanent magnet embedded hole 31 extends in the axial direction. A permanent magnet 40 is inserted into the permanent magnet embedded hole 31. Specifically, one flat permanent magnet 40 is embedded per pole in the embedded permanent magnet rotor 20 in the circumferential direction. The permanent magnet 40 is formed in a flat plate shape having a rectangular cross section, and is magnetized in the thickness direction. The flat permanent magnet 40 is embedded perpendicular to the d-axis.

  As shown in FIG. 1, the permanent magnets 40 arranged in adjacent regions (one pole) are arranged so that the outer peripheral sides of the embedded permanent magnet rotor 20 are different poles. For example, when a certain permanent magnet 40 is arranged so that the teeth 103 side is the S pole, the permanent magnet 40 arranged in the adjacent region (one pole) is arranged so that the teeth 103 side is the N pole. .

  The permanent magnet embedded magnet rotor core 30 is provided with a flux barrier (hole) 32 so as to be continuous with the end of the permanent magnet embedded hole 31 on the q-axis side. The flux barrier 32 extends in the axial direction. Thus, in the permanent magnet embedded magnet rotor 20, the flux barrier 32 is formed at the q-axis side end of the permanent magnet 40.

Per one pole, that is, the angle θr from the center O is 45 °, and the angle θn formed at the outermost peripheral corner of the permanent magnet 40 is 25 °.
As shown in FIG. 3, six grooves (concave portions) 33, 34, 35, 36, 37, and 38 are symmetric with respect to the d axis per pole on the outer peripheral surface of the embedded permanent magnet rotor 20 (rotor core 30). Is provided. Each of the grooves 33 to 38 extends in the axial direction. Each of the grooves 33 to 38 has a rectangular cross section. And as for the grooves 33-38, one long side of a rectangle (rectangle) forms the bottom part of a groove | channel, and the other long side is opening. The widths (lengths in the circumferential direction) of the openings of the grooves 33 to 38 are equal.

  The four first grooves 33, 34, 35, and 36 are provided symmetrically with respect to the d axis on the outer peripheral side of the permanent magnet 40 (permanent magnet embedded hole 31). Further, the two second grooves 37 and 38 are provided symmetrically with respect to the d axis in a region not on the outer peripheral side of the permanent magnet 40 on the outer peripheral surface of the permanent magnet embedded magnet rotor.

  The angle formed by the centers of the two center grooves 33 and 34 near the center of the four first grooves 33 to 36 is θ1, and the center adjacent to the center of the outer groove 35 of the four first grooves 33 to 36. When the angle formed by the center of the groove 33 and the angle formed by the center of the center groove 34 adjacent to the center of the outer groove 36 of the four first grooves 33 to 36 is θ2, θ1 ≧ θ2. Yes. More specifically, θ1> θ2.

  Further, the angle formed by the center of the second groove 37 adjacent to the center of the outer groove 35 of the four first grooves 33 to 36, and the outer groove 36 of the four first grooves 33 to 36. When the angle formed by the center of the second groove 38 adjacent to the center is θ3, θ2 = θ3.

  Here, θ1 is 10 ± 0.25 ° in mechanical angle and 40 ± 1 ° in electrical angle. Θ2 is 6 ± 0.25 ° in mechanical angle and 24 ± 1 ° in electrical angle. Furthermore, θ3 is 6 ± 0.25 ° in mechanical angle and 24 ± 1 ° in electrical angle.

  More specifically, θ1 is 10 ° in mechanical angle (40 ° in electrical angle). Θ2 is 6 ° in mechanical angle (24 ° in electrical angle). Furthermore, θ3 is 6 ° in mechanical angle (24 ° in electrical angle).

Further, θ1 is three times or more the opening angle θ10 (see FIG. 3) at the tip of the tooth 103. For example, the opening angle θ10 is about 3 ° in mechanical angle.
Next, the operation of the rotating electrical machine 10 configured as described above will be described.

  When the rotating electrical machine is driven, a three-phase current is supplied to the coil 104 of the stator 100, a rotating magnetic field is generated in the stator 100, and the rotating magnetic field acts on the permanent magnet embedded magnet rotor 20. Then, the permanent magnet embedded magnet rotor 20 rotates in synchronization with the rotating magnetic field by the magnetic attractive force and repulsive force between the rotating magnetic field and the permanent magnet 40.

  Six grooves 33 to 38 are provided per pole on the outer peripheral surface of the permanent magnet embedded magnet rotor 20, and four of the first grooves 33 to 36 are provided symmetrically with respect to the d axis on the outer peripheral side of the permanent magnet 40. ing. The two second grooves 37 and 38 are provided symmetrically with respect to the d axis in a region that is not on the outer peripheral side of the permanent magnet 40. An angle θ1 formed by two center grooves 33 and 34 closer to the center of the four first grooves 33 to 36, and a center groove 33 adjacent to the outer grooves 35 and 36 of the four first grooves 33 to 36, As a relationship of the angle θ2 formed by 34, θ1 ≧ θ2. In particular, θ1> θ2. In addition, as a relation of the angle θ3 formed by the second grooves 37 and 38 adjacent to the outer grooves 35 and 36 among the four first grooves 33 to 36, θ2 = θ3.

  Here, there is no groove on the surface of the q-axis rotor, and torque reduction can be avoided without interfering with the magnetic flux path that generates reluctance torque. Therefore, as shown in FIG. 4, the cogging torque can be reduced by bringing the magnetic flux density distribution on the surface of the rotor 20 (rotor core 30) close to a sine wave shape, and the cogging torque can be reduced without causing a reduction in torque.

  Next, the maximum torque and the cogging torque will be described with reference to FIGS. At this time, the rotating electrical machine using the permanent magnet embedded magnet rotor 20 in which the grooves 33 to 38 are formed on the outer peripheral surface and the rotating electrical machine using the rotor in which no groove is formed are compared.

  FIG. 5A shows the measurement results of the maximum torque when the grooves 33 to 38 are formed on the outer peripheral surface of the rotor (this embodiment) and when the grooves are not formed (comparative example). The case where no is formed is shown as 1.00.

  FIG. 5B shows the measurement results of the cogging torque when the grooves 33 to 38 are formed on the outer peripheral surface of the rotor (this embodiment) and when the grooves are not formed (comparative example). The case where no is formed is shown as 1.00.

About the maximum torque in Fig.5 (a), when the grooves 33-38 are formed, it is 1.00.
The cogging torque in FIG. 5B is 0.09 when the grooves 33 to 38 are formed.

Therefore, it can be seen that providing the grooves 33 to 38 can reduce the cogging torque by about 90% while maintaining the maximum torque.
Thus, the cogging torque can be reduced without reducing the maximum torque by providing six grooves per pole on the surface of the rotor. Moreover, there is only one kind of electrical steel sheet, which is advantageous in terms of cost.

  Next, the mechanical angle X (= 1/2 · θ1) between the d-axis and the centers of the grooves 33 and 34 in FIG. 3 and the d-axis and the centers of the grooves 35 and 36 will be described with reference to FIGS. The cogging torque relating to the mechanical angle Z formed by the mechanical angle Y, d-axis and the centers of the grooves 37, 38 will be described.

  In FIG. 6, the horizontal axis represents the mechanical angle X (= 1/2 · θ1) between the d axis in FIG. 3 and the centers of the grooves 33 and 34, the vertical axis represents the cogging torque, and the mechanical angle X ( = 1/2 · θ1) is 5 ° (θ1 is a mechanical angle of 10 °), θ2 is a mechanical angle of 6 °, and θ3 is a mechanical angle of 6 °. u. ]. At this time, θ2 is 6 ° in mechanical angle, and θ3 is 6 ° in mechanical angle. The cogging torque in FIG. 6 has a minimum value when the mechanical angle X (= 1/2 · θ1) formed by the d-axis and the centers of the grooves 33 and 34 is 5 °.

  Therefore, the cogging torque can be reduced by setting the mechanical angle X (= 1/2 · θ1) between the d-axis and the centers of the grooves 33 and 34 to be around 5 °, that is, around 20 ° in electrical angle. I understand that I can do it. That is, it can be seen that the cogging torque can be reduced by setting θ1 to a mechanical angle of around 10 °, that is, an electrical angle of around 40 °.

  In FIG. 7, the horizontal axis represents the mechanical angle Y (= 1/2 · θ1 + θ2) formed by the d-axis in FIG. 3 and the centers of the grooves 35 and 36, and the vertical axis represents the cogging torque. The reference of the vertical axis is the same as that in FIG. 6, and the cogging torque measurement result when θ1 is 10 ° mechanical angle, θ2 is 6 ° mechanical angle, and θ3 is 6 ° mechanical angle is 1 [p. u. ]. At this time, θ1 is 10 ° in mechanical angle, and θ3 is 6 ° in mechanical angle. The cogging torque in FIG. 7 has a minimum value when the mechanical angle Y (= 1/2 · θ1 + θ2) formed between the d-axis and the centers of the grooves 35 and 36 is 11 °.

  Therefore, the cogging torque can be reduced by setting the mechanical angle Y (= 1/2 · θ1 + θ2) between the d-axis and the centers of the grooves 35 and 36 to be around 11 °, that is, around 44 ° in electrical angle. I understand that I can do it. That is, it can be seen that the cogging torque can be reduced by setting θ2 to a mechanical angle of about 6 °, that is, an electrical angle of about 24 °.

  In FIG. 8, the horizontal axis represents the mechanical angle Z (= 1/2 · θ1 + θ2 + θ3) formed by the d axis in FIG. 3 and the centers of the grooves 37 and 38, and the vertical axis represents cogging torque. The reference of the vertical axis is the same as that in FIG. 6, and the cogging torque measurement result when θ1 is 10 ° mechanical angle, θ2 is 6 ° mechanical angle, and θ3 is 6 ° mechanical angle is 1 [p. u. ]. At this time, θ1 is 10 ° in mechanical angle, and θ2 is 6 ° in mechanical angle. The cogging torque in FIG. 8 has a minimum value when the mechanical angle Z (= 1/2 · θ1 + θ2 + θ3) formed by the d-axis and the centers of the grooves 37 and 38 is 17 °.

  Accordingly, the cogging torque can be reduced by setting the mechanical angle Z (= 1/2 · θ1 + θ2 + θ3) between the d-axis and the centers of the grooves 37 and 38 to be around 17 °, that is, around 68 ° in electrical angle. I understand that I can do it. That is, it can be seen that the cogging torque can be reduced by setting θ3 to a mechanical angle of about 6 °, that is, an electrical angle of about 24 °.

According to the above embodiment, the following effects can be obtained.
(1) As a configuration of a magnet-embedded rotary electric machine, a permanent magnet embedded magnet rotor 20 and a stator 100 are provided. Four first grooves 33 to 36 per pole are provided symmetrically with respect to the d axis on the outer peripheral side of the permanent magnet 40 on the outer peripheral surface of the embedded permanent magnet rotor, and on the outer peripheral surface of the embedded permanent magnet rotor. Two second grooves 37 and 38 per pole are provided in a region not on the outer peripheral side of the permanent magnet 40 symmetrically with respect to the d axis. Further, the angle formed by the two center grooves 33 and 34 closer to the center of the four first grooves 33 to 36 is θ1, and the center adjacent to the outer grooves 35 and 36 of the four first grooves 33 to 36 is set. When the angle formed by the grooves 33 and 34 is θ2, θ1 ≧ θ2. Thus, the cogging torque can be suppressed (reduced) by bringing the magnetic flux density distribution on the surface of the rotor closer to a sine wave shape. As a result, the cogging torque can be suppressed without causing a reduction in torque.

(2) θ1> θ2. As a result, the cogging torque can be further reduced without causing a decrease in torque.
(3) θ1 is 10 ± 0.25 ° in mechanical angle and 40 ± 1 ° in electrical angle, and θ2 is 6 ± 0.25 ° in mechanical angle and 24 ± 1 ° in electrical angle. This is preferable in reducing the cogging torque.

  (4) When the angle formed by the second grooves 37 and 38 adjacent to the outer grooves 35 and 36 among the four first grooves 33 to 36 is θ3, θ2 = θ3. As a result, the cogging torque can be further reduced without causing a decrease in torque.

(5) It is practically preferable that θ1 is three times or more the opening angle θ10 at the tip of the tooth 103.
(6) When θ3 is 6 ± 0.25 ° in mechanical angle and 24 ± 1 ° in electrical angle, it is preferable for reducing cogging torque.

The embodiment is not limited to the above, and may be embodied as follows, for example.
-The shape of the groove does not matter. Besides a rectangle, for example, a V shape or a trapezoidal shape may be used.
-The number of poles is not limited to eight. There may be more or less than eight poles. In this case, the embodiment is expressed by a mechanical angle, but it may be applied in terms of an electrical angle.

  DESCRIPTION OF SYMBOLS 10 ... Embedded magnetic rotating machine, 20 ... Embedded permanent magnet rotor, 33 ... Groove, 34 ... Groove, 35 ... Groove, 36 ... Groove, 37 ... Groove, 38 ... Groove, 100 ... Stator, 103 ... Teeth 104, coil, G, gap.

Claims (5)

A permanent magnet embedded magnet rotor having a cylindrical shape and a flat permanent magnet embedded perpendicularly to the d-axis;
Teeth that are arranged on the outer peripheral side of the permanent magnet embedded magnet rotor and in which a coil is wound on the inner peripheral side are juxtaposed in the circumferential direction, and a gap is formed between the outer peripheral surface of the embedded permanent magnet rotor and the gap. A stator that is opposed to each other,
In a magnet-embedded rotary electric machine with
Four first grooves per pole are provided symmetrically with respect to the d axis on the outer peripheral side of the permanent magnet on the outer peripheral surface of the permanent magnet embedded magnet rotor, and the outer peripheral surface of the permanent magnet embedded magnet rotor is Two second grooves per pole are provided symmetrically with respect to the d axis in a region that is not on the outer peripheral side of the permanent magnet,
When the angle formed by two center grooves closer to the center of the four first grooves is θ1, and the angle formed by the center groove adjacent to the outer groove of the four first grooves is θ2, θ1 A magnet-embedded rotating electrical machine characterized by ≧ θ2.   The embedded magnetic rotating electric machine according to claim 1, wherein θ1> θ2.   3. The embedded magnet type rotating electrical machine according to claim 1, wherein the θ1 is 40 ± 1 ° in electrical angle, and the θ2 is 24 ± 1 ° in electrical angle.   4. The structure according to claim 1, wherein θ <b> 2 = θ <b> 3 when the angle formed by the second groove adjacent to the outer groove of the four first grooves is θ <b> 3. The magnet-embedded rotary electric machine described in 1.   5. The magnet-embedded rotary electric machine according to claim 1, wherein the θ <b> 1 is three times or more an opening angle of a tip end of the tooth.