JPH1189145A - Permanent magnet type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the reluctance torque of a permanent magnet type motor and to improve the efficiency of the motor. SOLUTION: In an inner rotor-type permanent magnet type motor, a first core 13 where the permanent magnets 11 and 12 of respective magnetic poles are embedded and a second core 17, where holes 14 and 15 are formed in places corresponding to permanent magnets 11 and 12 and holes 16, are formed for the respective magnetic poles along the outer diameter side of the core 10 are overlapped by adjusting them to (d) and (q) shafts, so as to constitute a rotor core 10. In a first core 13, the two permanent magnets 11 and 12 are embedded into a chevron-shape with respect to a q-axis in a plane near the center line of the magnetic poles. A second core 17 has holes for flux barrier 14 and 15, which are contained in the holes of the permanent magnets 11 and 12 and the holes for a reluctance adjustment 16, which are dislocated from the holes 14 and 15 for flux barrier and are positioned in the outer diameter side of the rotor core 10, for the respective magnetic poles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner rotor type permanent magnet motor used for a compressor or the like, and more particularly, to a permanent magnet type motor for efficiently utilizing a reluctance torque of a motor to improve efficiency. .

[0002]

2. Description of the Related Art An inner rotor of a permanent magnet type motor of this type has a permanent magnet embedded in a rotor core, and for example, those shown in FIGS. 5 and 6 have been proposed. As shown in FIG. 5, plate-shaped permanent magnets 3 are arranged in the circumferential direction along the outer diameter of the rotor core 2 in the stator core 1 of 24 slots by the number of poles (4 poles) of the permanent magnet type motor. A flux barrier 4 is formed between adjacent permanent magnets 3 to prevent short-circuit and leakage of magnetic flux.
Reference numeral 5 denotes a center hole (a hole for a shaft).

Here, assuming that the magnetic flux distribution in the gap (between the teeth of the stator core 1 and the permanent magnet 3) formed by the permanent magnet 3 is sinusoidal, the torque T of the permanent magnet type motor is T = Pn ｛Φa ・ Ia ・ cosβ-0.5 (Ld
−Lq) · I ² · sin2β}. T is the output torque, Φa is the armature interlinkage flux by the permanent magnet on the d and q coordinate axes, Ld and Lq are the d and q axis inductances,
Ia is the amplitude of the armature current on the d, q coordinate axes, β is d, q
The lead angle, Pn, of the armature current on the coordinate axis from the q axis is the number of pole pairs.

[0004] In the above equation, the first term is the magnet torque by the permanent magnet 3, and the second two terms are the reluctance torque generated by the difference between the d-axis inductance and the g-axis inductance. For details, see T. IEEE Ja
pan, Vol. See article 117-D, No 7, 1997. The rotor core 2 shown in FIG.
Although the configuration has a permanent magnet 6 having a shape different from that of the permanent magnet 3 shown in FIG.

[0005]

However, in the permanent magnet type motor, since the permanent magnets 3 and 4 having low magnetic permeability are interposed at right angles in the magnetic path of the d-axis, the d-axis inductance Ld is originally small. Since the permanent magnets 3, 4 which are relatively large compared to the q-axis magnetic path are embedded along the magnetic path, the q-axis inductance Lq is not much different from Ld. As described above, since the q-axis inductance Lq is small, the value of the parameter (Ld−Lq) in the above equation becomes small, and thus there is a disadvantage that the reluctance torque is small.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a permanent magnet type motor capable of increasing the q-axis inductance and consequently increasing the reluctance torque and improving the efficiency of the motor. To provide.

[0007]

In order to achieve the above object, the present invention relates to a permanent magnet type motor having a rotor core therein, wherein the rotor core accommodates permanent magnets in accordance with the number of poles of the permanent magnet type motor. And a core having a plurality of permanent magnets for each magnetic pole, and a core having no permanent magnet and having only a hole for flux barrier and a hole for reluctance adjustment.

According to the present invention, there is provided a permanent magnet type motor in which a magnet-embedded field iron core (rotor core) is arranged in a stator core, wherein a plurality of permanent magnets are provided in accordance with the number of poles of the permanent magnet type motor. And a second core having holes formed at locations opposed to the permanent magnets and having holes formed along the outer diameter side of the rotor core for each magnetic pole. The rotor core is overlapped with the rotor core.

In this case, the first core embeds the permanent magnets near the center line between the magnetic poles and in a C-shape with respect to the q axis, and has 2P (P: positive integer) permanent magnets. A magnetic pole of a P pole is formed, and the holes of the second core are used for a flux barrier included in the holes of the permanent magnet and for reluctance adjustment at positions off the holes for the flux barrier. Good. In addition, the hole for the flux barrier of the second core may be parallel to the hole in which the permanent magnet is buried and closer to the outer diameter side of the core.

Further, in the first core, the electromagnetic steel sheet including the shape hole and the center hole of the permanent magnet, and in the second core, including the hole and the center hole, are punched by a press. Laminate the first
And the second core may be integrated, and the permanent magnet may be embedded in the first core and magnetized. Furthermore, a DC brushless motor may be provided by incorporating the core as a rotor core.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS. In the permanent magnet type motor of the present invention, if the inner core is constituted by a core having a permanent magnet and a core not having the same permanent magnet, that is, the inner core includes a core that generates a magnet torque and a core that increases a reluctance torque. If configured,
The focus is on the fact that a highly efficient motor can be obtained.

Therefore, as shown in FIGS. 1 to 3,
The rotor core 10 of this permanent magnet type motor has a first core (iron core) 13 having a hole for burying two permanent magnets 11 and 12 for each magnetic pole, and a flux barrier hole 14 having no permanent magnet. , 15 and hole 1 for reluctance adjustment
The second core (iron core) 17 having only 6 is superimposed and combined. Reference numeral 18 denotes a center hole (a hole for a shaft). Further, the first core 13 is at least half of the rotor core 10, that is, at least half of the laminated length (total lamination length) described later.

The permanent magnets 11 and 12 of the first core 13 are
It has a rectangular cross section and is arranged near the center line a between the magnetic poles and at a predetermined angle, that is, embedded in a C shape with respect to the q axis. The holes 14 and 15 formed in the second core 17 face (are formed in parallel with) the permanent magnets 11 and 12 and
It is slightly smaller (elongated) than 1,12.
That is, as shown by a solid line and a wavy line in FIG. 4, the first core 13 and the second core 17 are overlapped and the d-axis and the q-axis are overlapped.
4, 15 are included in the shape of the permanent magnet. The holes 16 for adjusting the reluctance are located on the outer diameter side of the holes 14 and 15 for the flux barrier for each magnetic pole, and the permanent magnets 11 and 1 are provided.
2 and has a long and thin shape (for example, an inverted arc shape).

The number of permanent magnets in each magnetic pole is two.
It may be more. In this case, the number of flux barrier holes may be determined according to the permanent magnet. Also,
The number of the permanent magnets 11 is 8, but 2P (P; a positive integer)
May be arranged to form a P pole magnetic pole. In this case, the number of flux barrier holes and the number of reluctance adjustment holes are determined in accordance with the permanent magnet, and the stator core winding is determined. Is applied in accordance with the magnetic pole of the P pole.

The inductance will be described with reference to the rotor configuration diagram shown in FIG. The three-phase (U-phase, V-phase and W-phase) armature windings are applied to the 24-slot stator core 19, but the number of slots and the armature windings may be different. In the stator core 19,
For example, the outer-side winding is a U-phase, the inner-side winding is a W-phase, and the intermediate winding is a V-phase. In the first core 13, since the area occupied by the permanent magnets 11 and 12 is large (broken line in FIG. 4; see FIG. 2), the magnet torque can be maximized, but the q-axis inductance is small. That is, the relaxation torque is reduced as in the conventional case.

In the second core 17, holes 16 for adjusting reluctance and holes 14, 1 for flux barrier are provided.
5, the q-axis inductance Lq is increased, the d-axis inductance Ld is decreased, only the reluctance torque is generated, and the inductance difference (Lq−L
d) is increased, and thus the reluctance torque is increased. The holes 14 and 15 of the second core 17 are
The flux barrier effect is effectively exerted because they are parallel to 1, 12, and the difference in inductance (Lq-Ld) is further increased by moving the holes 14, 15 to the outer diameter side of the rotor.

As described above, mainly the magnet torque is generated by the first core 13 and only the reluctance torque is generated by the second core 17. Therefore, the size of the permanent magnets 11 and 12 can be determined so that the magnet torque is maximized without considering the reluctance torque in the first core 13, and the reluctance torque is maximized in the second core 17. The holes 14, 15, and 16 can be determined as described above, and the magnet torque and the reluctance torque increase, so that a highly efficient motor can be obtained. Also, the size of the permanent magnets 11 and 12 and the holes 14 and
Depending on the magnitudes of 15 and 16, desired magnet torque and reluctance torque can be obtained, that is, a motor having an adaptive motor torque can be obtained.

Meanwhile, in the rotor core 10, electromagnetic steel sheets are stamped and laminated by press to integrate the first and second cores 13 and 17, while the permanent magnets 11 and 12 are embedded in the first core 13. And magnetize. At the time of the press,
The shape holes and the center holes (shaft holes) 18 of the permanent magnets 11 and 12 may be punched out, and the flux barrier holes 14 and 15 and the reluctance adjustment hole 16
Further, since it suffices to punch through the center hole 18, the manufacturing efficiency is not reduced, that is, the cost is not changed from the conventional one, and the cost is not increased. In addition, if the rotor core formed as described above is incorporated into a DC brushless motor and used as a compressor motor or the like of an air conditioner,
It is possible to improve the performance of the air conditioner (increase in operation efficiency, decrease in vibration and noise) without increasing costs.

[0019]

As described above, according to the first aspect of the present invention, the rotor core accommodates the permanent magnets in accordance with the number of poles of the permanent magnet type motor, and the permanent magnet of each magnetic pole is accommodated. Since it is composed of a core composed of a plurality of magnets and a core having no permanent magnet and having only a hole for flux barrier and a hole for reluctance adjustment, reluctance torque can be increased and motor efficiency can be increased. There is an effect that improvement can be achieved.

According to the second aspect of the present invention, in a permanent magnet type motor in which a magnet-embedded field core (rotor core) is arranged in a stator core, the number of poles of the permanent magnet type motor is adjusted. A first core in which a plurality of permanent magnets are embedded and a second core in which holes are formed at locations opposed to the permanent magnets and holes are formed along the outer diameter side of the rotor core for each magnetic pole, d , And the rotor core is superimposed on the q axis, so that the q axis inductance is large and d
The shaft inductance can be reduced, and the reluctance torque can be increased. Further, the magnet torque can be increased, and as a result, there is an effect that a highly efficient motor can be obtained.

According to the third aspect of the present invention, in the second aspect, the first core is provided with the permanent magnet near the center line between the magnetic poles.
Embedded in a C-shape with respect to the q axis, and 2P pieces (P;
P pole is formed by a permanent magnet of (positive integer), and the holes of the second core are for the flux barrier included in the holes of the permanent magnet and at the positions deviated from the holes for the flux barrier. Since it is for reluctance adjustment, in addition to the effect of claim 2, there is an effect that reluctance torque can be adjusted and magnet torque can be generated to the maximum.

According to the fourth aspect of the present invention, in the second or third aspect, the hole for the flux barrier of the second core is parallel to the hole in which the permanent magnet is embedded, and is close to the outer diameter side of the core. In addition to the effects of the second and third aspects, the flux barrier effect is effective, and the inductance is different, so that there is an effect that a motor with higher efficiency can be obtained.

According to the fifth aspect of the present invention, the electromagnetic steel sheet including the hole and the center hole of the permanent magnet in the first core and the hole and the center hole of the second core is formed in the second core. Since the first and second cores are integrated by laminating the punched electromagnetic steel sheets by pressing, and the permanent magnets are embedded in the first core and magnetized, it is possible to avoid an increase in manufacturing cost. That is, there is an effect that the cost is not different from the conventional one.

According to the invention of claim 6, according to claim 1,
The DC brushless motor is obtained by incorporating a core as a rotor core in 2, 3, 4 or 5.
In addition to the effects of 2, 3, 4 or 5, when used as a compressor motor of an air conditioner, for example, there is an effect that the performance of the air conditioner can be improved without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an inner rotor of a permanent magnet type motor according to an embodiment of the present invention.

FIG. 2 is a schematic partial plan view of the inner rotor shown in FIG.

FIG. 3 is a schematic partial plan view of the inner rotor shown in FIG. 1;

FIG. 4 is a schematic plan view of a permanent magnet motor having the inner rotor shown in FIG.

FIG. 5 is a schematic plan view of a conventional permanent magnet type motor rotor.

FIG. 6 is a schematic plan view of a conventional permanent magnet type motor rotor.

[Explanation of symbols]

 Reference Signs List 10 rotor core (magnet embedded field core) 11, 12 permanent magnet 13 first core 14, 15 holes (for flux barrier) 16 holes (for reluctance adjustment) 17 second core 18 center hole (for shaft) 19 Stator core

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02K 29/00 H02K 29/00 Z

Claims (6)

[Claims] 1. A permanent magnet type motor having a rotor core therein, wherein the rotor core accommodates permanent magnets in accordance with the number of poles of the permanent magnet type motor, and comprises a plurality of permanent magnets for each magnetic pole. A permanent magnet type motor comprising a core having no permanent magnet and having only a hole for flux barrier and a hole for reluctance adjustment. 2. A permanent magnet motor in which a magnet-embedded field core (rotor core) is disposed in a stator core, wherein a plurality of permanent magnets of each magnetic pole are used in accordance with the number of poles of the permanent magnet motor. The embedded first core and a second core having holes formed at locations opposed to the permanent magnets and having holes formed along the outer diameter side of the rotor core for each magnetic pole are arranged on the d and q axes. A permanent magnet type motor, wherein the rotor core is superposed together. 3. The first core embeds the permanent magnet near a center line between magnetic poles and in a C-shape with respect to the q axis.
And a magnetic pole of P pole is formed by 2P (P; a positive integer) permanent magnets, and the holes of the second core are used for a flux barrier included in the holes of the permanent magnet and for the flux barrier. 3. The magnet type motor according to claim 2, which is for adjusting reluctance at a position deviated from the hole. 4. The permanent magnet type according to claim 2, wherein the hole for the flux barrier of the second core is parallel to the hole in which the permanent magnet is buried, and is close to the outer diameter side of the core. motor. 5. The electromagnetic steel sheet including the shape hole and the center hole of the permanent magnet in the first core and the hole and the center hole in the second core is punched by a press, and the punched electromagnetic steel sheet is removed. The permanent magnet type motor according to claim 2 or 3, wherein the first and second cores are laminated to be integrated, and the permanent magnet is embedded and magnetized in the first core. 6. A permanent magnet motor according to claim 1, wherein said core is incorporated as a rotor core to form a DC brushless motor.