JP2015186353A - permanent magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of easily improving demagnetization resistance of a permanent magnet in a permanent magnet motor where a stator coil is wound in a distributed winding manner.SOLUTION: When the number of slots 113 in a stator 110 is defined as (s), a saturation magnetic flux density of a tabular member forming the stator is defined as Bs, the number of magnetic poles in a rotor 120 is defined as (n), a length of a magnet insertion hole 123 is defined as L, a thickness and a residual magnetic flux density of a permanent magnet 124 are defined as H and Br and an interval between an outer peripheral surface 121 of the rotor and a tooth distal end face 112c of the stator is defined as G, the saturation magnetic flux density Bs is set within a range of [2.1(T)≤Bs≤2.25(T)], the residual magnetic flux density Br is set within a range of [1.2(T)≤Br≤1.45(T)], the interval G is set within a range of [0.5(mm)≤G≤0.6(mm)], and a width W (mm) of a tooth base part 112a is set to satisfy an inequality in the figure.

Description

  The present invention relates to a permanent magnet motor, and more particularly to a permanent magnet motor in which a stator winding is wound in a distributed winding manner.

For example, a permanent magnet motor disclosed in Patent Document 1 is used as an electric motor that drives a device (for example, a compressor provided in a refrigerator, an air conditioner, or the like, a vehicle, or a vehicle-mounted device mounted on the vehicle). Yes.
The permanent magnet motor disclosed in Patent Document 1 includes a stator and a rotor that can rotate relative to the stator. The stator has a stator core formed by laminating electromagnetic steel plates and a stator winding. The stator core has a plurality of teeth arranged along the circumferential direction. The stator winding is wound around each tooth by a distributed winding method or a concentrated winding method. In the rotor, main magnetic pole portions and auxiliary magnetic pole portions are alternately arranged along the circumferential direction. A magnet insertion hole is formed in the main magnetic pole portion, and a permanent magnet is inserted in the magnet insertion hole.
Moreover, the rotor of the permanent magnet motor disclosed in Patent Document 1 has a slit for preventing demagnetization of the permanent magnet outside the magnet insertion hole.

JP 2012-95474 A

Patent Document 1 discloses a technique for preventing demagnetization of a permanent magnet by forming a slit outside the permanent magnet of the rotor.
However, the method of forming slits on the outer side of the permanent magnet of the rotor is troublesome because it is necessary to set the shape and position of the slits.
As a result of various studies on techniques for preventing the demagnetization of the permanent magnet of the permanent magnet motor, the present inventor has performed demagnetization of the permanent magnet in the permanent magnet motor in which the stator winding is wound around the teeth by the distributed winding method. We have found a technique that can be easily prevented.
Accordingly, an object of the present invention is to provide a technique capable of easily preventing demagnetization of a permanent magnet in a permanent magnet motor in which a stator winding is wound around a tooth by a distributed winding method.

［式１］
本発明では、固定子を構成する板状部材の飽和磁束密度Ｂｓ、回転子の永久磁石の残留磁束密度Ｂｒ、回転子の外周面と固定子のティースのティース先端面との間の間隔Ｇ、固定子のティースのティース基部の幅Ｗを、それぞれの設定条件が満足されるように設定することにより、固定子巻線が分布巻方式でティースに巻き付けられている永久磁石電動機における永久磁石の減磁を簡単に防止することができる。
主磁極部の磁石挿入孔および磁石挿入孔に挿入する永久磁石の断面形状は種々変更可能である。本発明の異なる形態では、磁石挿入孔および永久磁石は、軸方向に直角な断面で見て、回転子の主磁極部のｄ軸と交差する方向に直線状に延びている。
「ｄ軸」は、主磁極部の周方向中心と回転子中心を結ぶ線である。
本発明の他の異なる形態では、回転子の外周面は、軸方向に直角な断面で見て、主磁極部のｄ軸と交差し、外周側に飛び出ている第１の曲線形状に形成されている第１の曲線部分と、補助磁極部のｑ軸と交差し、外周側に飛び出ている第２の曲線形状に形成されている第２の曲線部分により形成されている。そして、第２の曲線部分の第２の曲線形状の曲率半径が、第１の曲線部分の第１の曲線形状の曲率半径より大きく設定されている。典型的には、第１の曲線形状は、ｄ軸上の回転子中心を中心とする円弧形状であり、第２の曲線形状は、ｑ軸上の、回転子中心より第２の曲線部分と反対側に離れた箇所を中心とする円弧形状である。
「ｑ軸」は、回転子の補助磁極部の周方向中心と回転子中心を結ぶ線である。
本形態では、間隔Ｇとして、回転子の外周面の第１の曲線部分と固定子のティースのティース先端面との間の間隔が用いられる。 The permanent magnet motor of the present invention includes a stator and a rotor that can rotate relative to the stator and has permanent magnets.
The stator includes a plate member having magnetism, typically a stator core in which electromagnetic steel plates are laminated, and a stator winding. The stator core includes a stator yoke extending along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and teeth extending along the radial direction from the stator yoke. The teeth are provided at a tooth base portion extending in the radial direction from the stator yoke, and at a tip end side of the tooth base portion, and extend along the circumferential direction and have a tooth tip surface formed on the opposite side of the stator yoke. The teeth have a tip portion. A slot is formed by teeth adjacent in the circumferential direction. The stator winding is wound around the teeth. In the present invention, the stator winding is wound in a distributed winding manner.
In the rotor, the main magnetic pole portions and the auxiliary magnetic pole portions are alternately arranged along the circumferential direction when viewed in a cross section perpendicular to the axial direction. A magnet insertion hole is formed in the main magnetic pole portion, and a permanent magnet is inserted in the magnet insertion hole. As the permanent magnet, a rare earth magnet is typically used.
Here, the number of slots of the stator is s, the number of magnetic poles of the rotor (the number of main magnetic pole portions or auxiliary magnetic pole portions) is n, and the saturation magnetic flux density of the plate-like member constituting the stator (stator core) is Bs, Br is the residual magnetic flux density of the permanent magnet of the rotor, G is the distance between the outer peripheral surface of the rotor and the tooth tip surface of the stator teeth, L is the length of the magnet insertion hole, and the thickness of the permanent magnet Is H.
In the present invention, the residual magnetic flux density Br of the permanent magnet of the rotor is within the range of [2.1 (T) ≦ Bs ≦ 2.25 (T)] of the saturation magnetic flux density Bs of the plate-like member constituting the stator. The interval G is set within the range of [1.2 (T) ≦ Br ≦ 1.45 (T)] and the range of [0.5 (mm) ≦ G ≦ 0.6 (mm)].
Furthermore, in the present invention, the width W of the teeth base portion of the teeth of the stator is set so as to satisfy [Equation 1].

[Formula 1]
In the present invention, the saturation magnetic flux density Bs of the plate member constituting the stator, the residual magnetic flux density Br of the permanent magnet of the rotor, the gap G between the outer peripheral surface of the rotor and the tooth tip surface of the stator teeth, By setting the width W of the teeth base of the teeth of the stator so that the respective setting conditions are satisfied, the number of permanent magnets in the permanent magnet motor in which the stator winding is wound around the teeth in a distributed winding method is reduced. Magnetism can be easily prevented.
The cross-sectional shape of the permanent magnet inserted into the magnet insertion hole and the magnet insertion hole of the main magnetic pole portion can be variously changed. In a different form of the present invention, the magnet insertion hole and the permanent magnet extend linearly in a direction intersecting with the d-axis of the main magnetic pole portion of the rotor as viewed in a cross section perpendicular to the axial direction.
The “d-axis” is a line connecting the circumferential center of the main magnetic pole part and the rotor center.
In another different aspect of the present invention, the outer peripheral surface of the rotor is formed in a first curved shape that crosses the d-axis of the main magnetic pole portion and protrudes to the outer peripheral side when viewed in a cross section perpendicular to the axial direction. The first curve portion is formed by a second curve portion that intersects with the q axis of the auxiliary magnetic pole portion and is formed in a second curve shape that protrudes to the outer peripheral side. And the curvature radius of the 2nd curve shape of the 2nd curve part is set larger than the curvature radius of the 1st curve shape of the 1st curve part. Typically, the first curve shape is an arc shape centered on the rotor center on the d axis, and the second curve shape is a second curve portion on the q axis from the rotor center. It has a circular arc shape centered on a location away from the opposite side.
The “q-axis” is a line connecting the circumferential center of the auxiliary magnetic pole portion of the rotor and the rotor center.
In this embodiment, as the distance G, the distance between the first curved portion of the outer peripheral surface of the rotor and the tooth tip surface of the teeth of the stator is used.

  In the present invention, it is possible to easily prevent demagnetization of the permanent magnet in the permanent magnet motor in which the stator winding is wound around the teeth by the distributed winding method.

It is sectional drawing orthogonal to the axial direction of 1st Embodiment of the permanent magnet rotary machine of this invention. It is the elements on larger scale of FIG. It is sectional drawing orthogonal to the axial direction of 2nd Embodiment of the permanent magnet rotary machine of this invention. FIG. 4 is a partially enlarged view of FIG. 3. It is a figure which shows the relationship between the width | variety of teeth and a demagnetization start current.

Embodiments of the present invention will be described below with reference to the drawings.
In the present specification, the “axial direction” indicates the direction of the rotation center line passing through the rotor center in a state where the rotor is rotatably supported with respect to the stator. The “circumferential direction” is a circle centered on the rotor center when viewed in a cross section perpendicular to the axial direction (direction of the rotation center line) in a state where the rotor is rotatably supported with respect to the stator. Indicates the circumferential direction. The “radial direction” indicates a direction passing through the center of the rotor as viewed in a cross section perpendicular to the axial direction in a state where the rotor is rotatably supported with respect to the stator.
The “d axis” is a line connecting the circumferential center of the main magnetic pole part and the rotor center when viewed in a cross section perpendicular to the axial direction, and the “q axis” is viewed in a cross section perpendicular to the axial direction. The line connecting the center in the circumferential direction of the auxiliary magnetic pole part and the center of the rotor.

1 and 2 show a first embodiment of a permanent magnet motor of the present invention.
FIG. 1 is a cross-sectional view of the permanent magnet motor 100 of the present embodiment along the axial direction. FIG. 2 is a partially enlarged view of FIG.
Further, in the permanent magnet motor 100 of the present embodiment, the number of slots s of the stator 110 is 24, the number of magnetic poles of the rotor 120 (the number of main magnetic pole portions or auxiliary magnetic pole portions) n is 4 (the number of pole pairs is 2). ) Will be described.

The permanent magnet motor 100 according to the present embodiment includes a stator 110 and a rotor 120.
The stator 110 is configured by a laminate (referred to as a “stator core”) in which a plurality of thin electromagnetic steel plates are laminated in the axial direction.
The stator core is disposed on the outer peripheral side when viewed in a cross section perpendicular to the axial direction, and extends along the circumferential direction, and the rotor center O side along the radial direction from the stator yoke 111. The teeth 112 extend to the front.
The teeth 112 are provided on the tooth base 112a extending from the stator yoke 111 along the radial direction toward the rotor center O, and on the tip side (rotor 120 side) of the teeth base 112a, and extend along the circumferential direction. It has the teeth front-end | tip part 112b. The tooth front end portion 112b has tooth end portions extending on both sides in the circumferential direction with respect to the tooth base portion 112a. The tooth front end portion 112b has a tooth front end surface 112c formed on the side opposite to the stator yoke 111 (on the rotor 120 side). The tooth tip surface 112c is formed in an arc shape centered on the rotor center O.
A stator winding (not shown) is wound around the teeth 112 by a distributed winding method.

The rotor 120 is configured by a laminate (referred to as “rotor core”) in which a plurality of thin electromagnetic steel plates are laminated in the axial direction.
The rotor core has a main magnetic pole part a, b, c, d in which a magnet insertion hole 123 is formed and an auxiliary magnetic pole part ab, bc, cd, da in the circumferential direction when viewed in a cross section perpendicular to the axial direction. Alternatingly arranged along. By alternately arranging the main magnetic pole portions a to d and the auxiliary magnetic pole portions ab to da along the circumferential direction, both the magnet torque due to the magnetic flux of the permanent magnet and the reluctance torque due to the saliency of the auxiliary magnetic pole portion are used. Can do. The reluctance torque can be adjusted by adjusting the magnetic flux path width of the auxiliary magnetic pole portions ab to da.
In the present embodiment, the outer peripheral surface 121 of the rotor 120 is formed in a circular shape centered on the rotor center O when viewed in a cross section perpendicular to the axial direction.
A rotation shaft (not shown) is inserted into the rotation shaft insertion hole 122 of the rotor 120.

Further, in the present embodiment, the magnet insertion hole 123 is formed so as to extend linearly in a direction perpendicular to the d-axis of the main magnetic pole portions a to d when viewed in a cross section perpendicular to the axial direction. A permanent magnet 124 that extends linearly in a direction perpendicular to the d-axis of the main magnetic pole portions a to d (a cross-sectional shape perpendicular to the axial direction has a rectangular shape) is inserted into the magnet insertion hole 123. The permanent magnet 124 is inserted into the magnet insertion hole 123 so that the gaps 123a and 123b are formed at both ends of the magnet insertion hole 123. For example, the permanent magnet 124 is formed so that the length of the permanent magnet 124 is shorter than the length of the magnet insertion hole 123, and the permanent magnet is projected to the magnet insertion hole 123 side on the inner wall forming the magnet insertion hole 123. 124 positioning protrusions are formed. By providing a gap between the end of the permanent magnet 124 and the end of the magnet insertion hole, it is possible to prevent a short circuit of magnetic flux generated from the permanent magnet 124.
In the present embodiment, a rare earth magnet is used as the permanent magnet 124.
Further, a bridge portion (not shown) is formed between both end portions of the magnet insertion hole 123 and the outer peripheral surface 121 of the rotor 120 to prevent a short circuit of magnetic flux generated from the permanent magnet 124.
The permanent magnets 124 inserted into the magnet insertion holes 123 of the main magnetic pole portions a to d are magnetized so that the adjacent main magnetic pole portions a to d have different polarities. That is, it is magnetized so that the main magnetic pole portions a to d having S and N poles are alternately arranged in the circumferential direction. For example, in FIG. 2, the permanent magnet 124 of the main magnetic pole part a is magnetized to the S pole on the outer peripheral side and the N pole on the inner peripheral side, and the permanent magnets 124 of the main magnetic pole parts b and d adjacent to the main magnetic pole part a are The outer peripheral side is magnetized to the N pole and the inner peripheral side is magnetized to the S pole.

Next, regarding the permanent magnet motor 100 in which the stator winding is wound around the teeth 112 by the distributed winding method according to the present embodiment, the width W of the teeth base portion 112a of the teeth 112 (hereinafter referred to as “teeth width W”). And the demagnetization resistance (demagnetization start current) will be described.
In the permanent magnet motor 100 in which the number s of slots 113 of the stator 110 is 24 and the number of magnetic poles n of the rotor 120 is 4, the permanent magnet 124 of the rotor 120 includes, as shown in FIG. Magnetic flux flows through a maximum of six teeth 112 (112A to 112F in FIG. 2).
Therefore, the total value 6W (mm) of the teeth width W (mm) of the six teeth 112 (112A to 112F) (hereinafter referred to as “teeth width total value”) and the demagnetization start current (A) of the permanent magnet 124 The relationship was measured. The demagnetization start current is a current at which demagnetization of the permanent magnet is started, and indicates that the demagnetization is easier as the demagnetization start current is smaller.
The relationship between the total tooth width 6W of the six teeth 112 and the demagnetization start current is that the rotor 120 has a diameter of 54.8 mm and the number of slots 113 (slot number) s of the stator 110 is 24. The number of magnetic poles (number of magnetic poles) n of the child 120 is 4, the residual magnetic flux density Br of the permanent magnet 124 is 1.4 (T), and the saturation magnetic flux density Bs of the magnetic steel sheet constituting the stator 110 is 2.2 (T). The thickness H of the permanent magnet 124 is 2 mm, the length L of the magnet insertion hole 124 is 32 mm, and the gap (gap) G between the outer peripheral surface 121 of the rotor 120 and the tooth tip surface 112c of the teeth 121 of the stator 110. Was measured for a permanent magnet motor 100 having a diameter of 0.6 mm.

［式２］
［式２］は６個のティース１１２のティース幅合計値６Ｗを表しているから、１個のティース１１２のティース幅Ｗは、［式３］で表される。

［式３］
すなわち、前述した永久磁石電動機１００では、ティース１１２のティース幅Ｗが２．０ｍｍ以下である場合に、減磁開始電流の低下が抑制される。 FIG. 5 shows measurement results of the total tooth width 6 W (mm) of the six teeth 112 and the demagnetization start current (A).
From FIG. 5, when the total tooth width 6W of the six teeth 112 is 12.0 mm or less, the decrease of the demagnetization start current is suppressed, but the total tooth width of the six teeth 112 is It can be seen that when it exceeds 12.0 mm, the demagnetization start current rapidly decreases.
This condition is expressed by [Formula 2].

[Formula 2]
Since [Formula 2] represents the total tooth width 6W of the six teeth 112, the teeth width W of one tooth 112 is represented by [Formula 3].

[Formula 3]
That is, in the permanent magnet electric motor 100 described above, when the teeth width W of the teeth 112 is 2.0 mm or less, a decrease in demagnetization start current is suppressed.

  As a result of further measurement, the saturation magnetic flux density Bs of the electrical steel sheet constituting the stator 110 is within the range of [2.1 (T) ≦ Bs ≦ 2.25 (T)], and the permanent magnet 124 of the rotor 120 is measured. The distance between the outer peripheral surface 121 of the rotor 120 and the tooth front end surface 112c of the teeth 112 of the stator 110 within a range where the residual magnetic flux density Br is in the range of [1.2 (T) ≦ Br ≦ 1.45 (T)] When (gap) G is within the range of [0.5 (mm) ≦ G ≦ 0.6 (mm)], by satisfying the same condition as [Formula 2], It was found that the decrease was suppressed.

When the number of slots s of the stator 110 is 12 and the number of magnetic poles n of the rotor 120 is 4, the permanent magnet 124 of the rotor 120 is connected to a maximum of three (12/4) teeth 112. Magnetic flux flows. That is, when the number of slots s and the number of magnetic poles n are this combination, [Equation 2] represents the total tooth width 3W of the three teeth 112.
In addition, when the number of slots s of the stator 110 is 36 and the number of magnetic poles n of the rotor 120 is 6, the permanent magnet 124 of the rotor 120 is connected to a maximum of six (36/6) teeth 112. Magnetic flux flows. That is, when the number of slots s and the number of magnetic poles n are this combination, [Equation 2] represents the total tooth width value 6W of the six teeth 112.
Further, when the number of slots s of the stator 110 is 18 and the number of magnetic poles n of the rotor 120 is 6, the permanent magnet 124 of the rotor 120 has a maximum of three (18/6) teeth 112 interposed therebetween. Magnetic flux flows. That is, when the number of slots s and the number of magnetic poles n are this combination, [Equation 2] represents the total tooth width 3W of the three teeth 112.

［式４］
このような条件を満足するようにティース１１２のティース幅Ｗを設定することにより、ティース１１２の磁束密度がほぼ飽和して回転子１２０に流れる磁束が抑制される。その結果、回転子内部の磁束密度が、永久磁石１２４を減磁させる状態まで高くならないように抑制される。
なお、ティース１１２のティース幅Ｗの下限値は、永久磁石電動機１００の所望の特性に応じて設定される。 From the above measurement results, in the permanent magnet electric motor 100 in which the stator winding is wound around the teeth 112 by the distributed winding method, the number of slots of the stator 110 is s, the number of magnetic poles of the rotor 120 is n, and the stator 110 is Bs is the saturation magnetic flux density of the magnetic steel sheet, Br is the residual magnetic flux density of the permanent magnet 124 of the rotor 120, and the distance between the outer peripheral surface 121 of the rotor 120 and the tooth tip surface 112c of the teeth 112 of the stator 110 is When the length of the magnet insertion hole 123 is L and the thickness of the permanent magnet 124 is H, the saturation magnetic flux density Bs of the electrical steel sheet constituting the stator 110 is [2.1 (T) ≦ Bs ≦ 2. 25 (T)], the residual magnetic flux density Br of the permanent magnet 124 of the rotor 120 is within the range [1.2 (T) ≦ Br ≦ 1.45 (T)], and the gap G is [0.5]. (Mm) ≦ G ≦ 0.6 (mm)] Is set to 囲内, when the teeth width W of the teeth 112 of the stator 110 is set so as to satisfy [Expression 4], it is possible to prevent the demagnetization of the permanent magnet.

[Formula 4]
By setting the tooth width W of the teeth 112 so as to satisfy such conditions, the magnetic flux density of the teeth 112 is substantially saturated and the magnetic flux flowing through the rotor 120 is suppressed. As a result, the magnetic flux density inside the rotor is suppressed so as not to increase to a state where the permanent magnet 124 is demagnetized.
The lower limit value of the tooth width W of the tooth 112 is set according to desired characteristics of the permanent magnet motor 100.

In addition, if the diameter of the rotor 120 becomes large, the teeth width W which can prevent demagnetization of a permanent magnet will also become large. On the other hand, when the diameter of the rotor 120 is reduced, the teeth width W that can prevent the demagnetization of the permanent magnet is also reduced.
Here, the length L and the thickness H of the magnet insertion hole 123 can be increased as the diameter of the rotor 120 is increased, and are decreased as the diameter of the rotor 120 is decreased.
[Formula 4] includes the length L and thickness H of the magnet insertion hole 123, and the teeth width W that satisfies [Formula 4] increases as the diameter of the rotor 120 increases, As the diameter of the rotor 120 decreases, the diameter decreases.
Therefore, the teeth width W that satisfies [Equation 4] substantially takes the diameter of the rotor 120 into consideration.

3 and 4 show a second embodiment of the permanent magnet motor of the present invention.
FIG. 3 is a cross-sectional view along the axial direction of the permanent magnet electric motor 200 of the present embodiment. FIG. 4 is a partially enlarged view of FIG.
Further, in the permanent magnet motor 200 of the present embodiment, as in the case of the permanent magnet motor 100 of the first embodiment, the number of slots s of the stator 210 is 24 and the number of magnetic poles n of the rotor 220 is 4. explain.
The permanent magnet motor 200 of the present embodiment is different from the permanent magnet motor 100 of the first embodiment in the shape of the outer peripheral surface 221 of the rotor 220.

The permanent magnet motor 200 according to the present embodiment includes a stator 210 and a rotor 220.
The stator 210 is constituted by a stator core in which a plurality of thin plate-shaped electromagnetic steel plates are laminated along the axial direction.
The stator core is disposed on the outer peripheral side when viewed in a cross section perpendicular to the axial direction, and extends along the circumferential direction, and the rotor center O side along the radial direction from the stator yoke 211. The teeth 212 extend to the front. The teeth 212 include a teeth base 212a and a teeth tip 212b having a tooth tip 212c formed on the rotor 220 side. The teeth tip surface 212c is formed in an arc shape centered on the rotor center O.
A stator winding (not shown) is wound around the teeth 212 by a distributed winding method.

The rotor 220 is constituted by a rotor core in which a plurality of thin plate-shaped electromagnetic steel plates are stacked along the axial direction.
In the rotor core, when viewed in a cross section perpendicular to the axial direction, main magnetic pole portions a to d in which magnet insertion holes 223 are formed and auxiliary magnetic pole portions ab to da are alternately arranged along the circumferential direction. .
The outer peripheral surface 221 of the rotor 220 has a first curved portion 221A having a first curved shape that intersects with the d-axis of the main magnetic pole portions a to d and an auxiliary magnetic pole portion ab as viewed in a cross section perpendicular to the axial direction. The second curve portion 221B having the second curve shape intersecting with the q axis of .about.da. The first curved portion 221A is formed in an arc shape having a radius R1 with the center of curvature at the rotor center O on the center line (d axis) of the main magnetic pole portions a to d. Further, the second curved line portion 221B has a point P on the center line (q axis) of the auxiliary magnetic pole portions ab to da that is separated from the rotor center O on the opposite side to the second curved portion 221B. Are formed in an arc shape having a radius R2 (R2> R1).
The width along the circumferential direction of the first curved portion 221A and the second curved portion 221B (the width along the circumferential direction between the boundary portions 221a between the first curved portion 221A and the second curved portion 221B) is It can be selected appropriately.

In recent years, a sensorless control system has been used as a control system for permanent magnet motors. In this sensorless control method, it is assumed that the waveform of the induced voltage is a sine wave, and the rotor position is detected using the input voltage and the input current. When this sensorless control method is used, if the number of harmonic components included in the waveform of the induced voltage increases, the rotor position detection system is degraded. When the rotor position detection system is lowered, optimal control cannot be performed, and the efficiency of the permanent magnet motor is lowered.
In the present embodiment, the radius of curvature of the second curved portion 221B corresponding to the auxiliary magnetic pole portions ab to da is set larger than the radius of curvature of the first curved portion 221A corresponding to the main magnetic pole portions a to d. Therefore, the outer peripheral surface 221 of the rotor 220 does not change abruptly at the boundary portion 221a between the first curved portion 221A and the second curved portion 221B. Thereby, when the boundary portion 221a between the first curved portion 221A and the second curved portion 221B passes through the portion where the teeth 212 of the stator 210 are disposed, the magnetic flux flowing through the teeth 212 of the stator 210 is abruptly increased. Changes are prevented. By preventing a sudden change in the magnetic flux flowing through the tooth 212, the harmonic component contained in the induced voltage is reduced. Therefore, even when the sensorless control method is used, optimal control can be performed and the efficiency of the permanent magnet motor can be improved.

Also in the permanent magnet motor 200 of the present embodiment, like the permanent magnet motor 100 of the first embodiment, by setting the teeth width W of the teeth 212 so as to satisfy the above-described conditions, the permanent magnet Can be prevented.
In the present embodiment, the diameter of the rotor is the length between the first curved portions 221A (the length along the d-axis). Further, a gap G between the outer peripheral surface 221 of the rotor 220 and the tooth front end surface 212c of the tooth 212 of the stator 210 is a distance between the first curved portion 221A and the tooth front end surface 212c.

  That is, also in the permanent magnet motor 200 of the present embodiment, the number of slots of the stator 210 is s, the number of magnetic poles of the rotor 220 is n, the saturation magnetic flux density of the electrical steel sheet constituting the stator 210 is Bs, and the rotor 220 The permanent magnet 224 has a residual magnetic flux density Br, an interval between the outer peripheral surface 221 of the rotor 220 and the tooth tip surface 212c of the teeth 212 of the stator 210, G, a length of the magnet insertion hole 223, L, and a permanent magnet. When the thickness of 224 is H, the saturation magnetic flux density Bs of the magnetic steel sheet constituting the stator 210 is within the range of [2.1 (T) ≦ Bs ≦ 2.25 (T)], and the rotor 220 is permanent. The residual magnetic flux density Br of the magnet 224 is within the range of [1.2 (T) ≦ Br ≦ 1.45 (T)], and the gap G is [0.5 (mm) ≦ G ≦ 0.6 (mm)]. Of the teeth 212 of the stator 210. If the Isu width W is set so as to satisfy [Expression 4], it is possible to prevent the demagnetization of the permanent magnet.

The present invention is not limited to the configuration described in the embodiment, and various changes, additions, and deletions can be made without departing from the scope of the present invention.
The cross-sectional shapes of the magnet insertion hole and the permanent magnet are not limited to a linear shape (rectangular shape), and various shapes such as an arc shape and a V shape can be selected.
The combination of the number of slots of the stator and the number of magnetic poles of the rotor can be changed as appropriate.
The plate-like member constituting the stator is not limited to the electromagnetic steel plate.
The configurations described in the embodiments can be used alone or in combination with a plurality of appropriately selected configurations.

100, 200 Permanent magnet rotating machine 110, 210 Stator 111, 211 Stator yoke 112, 112A-112F, 212, 212A-212F Teeth 112a, 212a Teeth base 112b, 212b Teeth tip 112c, 212c Teeth tip 113, 213 Slots 120, 220 Rotors 121, 221 Outer peripheral surfaces 122, 222 Rotating shaft insertion holes 123, 223 Magnet insertion holes 123a, 123b, 223a, 223b Air gaps 124, 224 Permanent magnet 221A First curved portion 221B Second curved portion

Claims (3)

A stator and a rotor rotatable relative to the stator;
The stator is formed by laminating plate-like members, and is seen in a cross section perpendicular to the axial direction.
A stator yoke extending along the circumferential direction;
A tooth base extending along the radial direction from the stator yoke, and provided at a tip side of the teeth base, extending along the circumferential direction and having a tooth tip surface formed on the opposite side of the stator yoke. A plurality of teeth each having a tooth tip,
A plurality of slots formed by the teeth adjacent in the circumferential direction;
The rotor has a main magnetic pole portion and an auxiliary magnetic pole portion alternately arranged along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a magnet in which a permanent magnet is inserted in the main magnetic pole portion. A receiving hole is formed,
The stator is a permanent magnet motor having a stator winding wound around the teeth in a distributed winding manner,
The number of slots of the stator is s, the number of magnetic poles of the rotor is n, the saturation magnetic flux density of the plate member of the stator is Bs, the residual magnetic flux density of the permanent magnet of the rotor is Br, and the rotor When the gap between the outer peripheral surface of the stator and the teeth tip surface of the stator is G, the length of the magnet insertion hole is L, and the thickness of the permanent magnet is H, the plate-like member of the stator The saturation magnetic flux density Bs is in the range of [2.1 (T) ≦ Bs ≦ 2.25 (T)], and the residual magnetic flux density Br of the permanent magnet of the rotor is [1.2 (T) ≦ Br ≦ 1. 45 (T)], the gap G is set within the range of [0.5 (mm) ≦ G ≦ 0.6 (mm)], and the width W of the teeth base is

A permanent magnet motor characterized by being set to satisfy The permanent magnet motor according to claim 1,
The permanent magnet motor, wherein the magnet insertion hole and the permanent magnet extend linearly in a direction intersecting the d-axis of the main magnetic pole portion when viewed in a cross section perpendicular to the axial direction, The permanent magnet motor according to claim 1 or 2,
The outer peripheral surface of the rotor, when viewed in a cross section perpendicular to the axial direction, intersects the d-axis of the main magnetic pole portion and protrudes to the outer peripheral side with a first curved portion formed in a first curved shape. And the second curved portion formed in the second curved shape that intersects the q axis of the auxiliary magnetic pole portion and protrudes to the outer peripheral side, and the radius of curvature of the second curved shape is Is set to be larger than the radius of curvature of the curved shape of 1,
As the distance G, a distance between the first curved portion of the outer peripheral surface of the rotor and the teeth tip surface of the stator is used.

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