JPH10191585A - Motor buried with permanent magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high efficiency high output motor buried with permanent magnets by arranging permanent magnets having polarities in the direction vertical to those of a main magnet at the opposite ends of a permanent magnet thereby increasing the quantity of flux being generated from the permanent magnet and concentrating the flux to the center of pole. SOLUTION: A rotor 3 comprises four sets of permanent magnet 1 buried in a rotor core 3a made of a material having high permeability while alternating N and S poles and secured to a rotor shaft 4. Each permanent magnet 1 has arcuate shape projecting toward the central side of the rotor and auxiliary poles 2 having poles in the direction vertical to those of a main magnet are arranged at the opposite ends of each permanent magnet. Since the quantity of flux being generated from the permanent magnet can be increased, more magnet torque can be utilized. Furthermore, leakage flux at the opposite end of the permanent magnet contiguous to the outer circumference of the rotor can be covered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet embedded motor that uses a reluctance torque in addition to a magnet torque by embedding a permanent magnet in a rotor.

[0002]

2. Description of the Related Art Conventionally, there has been known a motor in which a permanent magnet is embedded in a rotor body made of a material having high magnetic permeability such as iron. FIG. 13 shows a conventional permanent magnet embedded motor. This permanent magnet embedded motor forms a rotor by embedding permanent magnets inside a rotor core made of an iron core of a high magnetic permeability material or a laminated silicon steel sheet. FIG. 13 shows a four-pole motor, in which four permanent magnets are arranged in the circumferential direction such that the N pole and the S pole are alternately arranged. The winding group applied to the stator generates a rotating magnetic field, and magnetic flux enters the rotor from the stator teeth.

With such a configuration, the inductance Ld in the d-axis direction, which connects the center of the permanent magnet and the center of the rotor, and the q-axis direction, which is a direction rotated by 90 electrical degrees with respect to the d-axis. , A reluctance torque is generated in addition to the magnet torque generated by the permanent magnet. Equation (1) shows this relationship.

T = Pn {Φa * Iq + 1/2 (Ld−Lq) * Id * Lq} (1) Pn: the number of pole pairs Φa: flux linkage Ld: d-axis inductance Lq: q Shaft inductance Id: d-axis current Iq: q-axis current Equation (1) shows the voltage equation after dq conversion. In the permanent magnet embedded motor, the d-axis direction is the direction in which the magnetic flux of the permanent magnet is generated, and the flow of the magnetic flux in the d-axis direction is as shown in FIG.
As shown in (1), since the magnetic flux passes through a permanent magnet portion having substantially the same magnetic permeability as air, the magnetic resistance increases and the d-axis inductance Ld becomes extremely small. On the other hand, since the q-axis direction, which is a direction that forms an electrical angle of 90 degrees with the d-axis direction, faces the side surface of the permanent magnet, the flow of magnetic flux in the q-axis direction passes through the magnet side surface as shown in the drawing. The magnetic resistance decreases, and as a result, the q-axis inductance Lq increases. For this reason, a difference is generated between the d-axis inductance Ld and the q-axis inductance Lq, and when the d-axis current Id flows, the reluctance torque shown in the second term in ｛｝ of the equation (1) is generated.

[0005] The total torque T of the embedded magnet motor is
As can be seen from equation (1), it is the sum of the magnet torque and the reluctance torque.

In the rotor, a magnet torque generated in a relationship between a rotating magnetic field generated by a stator winding group and a magnetic field of a permanent magnet, and a magnetic path formed by the rotating magnetic field are formed on a surface side of the rotor main body and at intervals between inner and outer permanent magnets. R is the combined torque with the reluctance torque generated by the
It is rotating in the direction.

[0007]

In the above-described conventional permanent magnet embedded motor, magnetic flux leaks at portions of both ends of the permanent magnet close to the outer peripheral portion of the rotor as shown in FIG. Was a problem.

The present invention has been made to solve such a conventional problem, and a permanent magnet embedded in a rotor has a Halbach magnet.
By applying net array, the amount of magnetic flux generated by the permanent magnet is increased by using the same amount of permanent magnet as before. By covering the wraparound of the magnetic flux generated at the end of the permanent magnet, concentrating the magnetic flux at the pole center and maximizing the use of the magnet torque generated by the same current, a high efficiency and high output permanent magnet embedded motor It is intended to provide.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a permanent magnet embedded motor having a structure in which permanent magnets are embedded in a rotor. It is characterized in that permanent magnets having a polarity in a vertical direction are arranged and the amount of magnetic flux generated by the permanent magnets is increased.

The Halbach manget array employed here will be described with reference to FIG. (A) is a magnet arrangement when the rotor of the four-pole motor is represented in a plane. Usually, the N pole and the S pole are alternately arranged in this manner. The magnetic flux flows like 1a, 2a,..., 1b, 2b,. (B) is (a)
Is a magnet having magnetic poles in a direction perpendicular to the main magnet represented by. These magnets are arranged such that the same polarity is opposed. The flow of magnetic flux is 6a, 7a, ..., 6b, 7b, ...
It becomes like. The magnet of (c) is a combination of the magnet of (a) and the magnet of (b). Thus, by adjoining magnets whose magnetic poles are in a vertical relationship, 2b and 7b,
3b and 8b, 4b and 9b strengthen each other, 2a and 7
a, 3a and 8a, 4a and 9a weaken each other. Therefore, as shown in (c), the magnetic force on one side is stronger than when a normal magnet arrangement is used. Thus, the magnetic force can be increased in any direction.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the amount of magnetic flux generated by the permanent magnet can be increased by the above configuration, so that the magnet torque generated by the same current is more effectively generated.

FIG. 12 shows a halbach magnet arr of the present invention.
FIG. 4 shows a magnetic flux distribution by a permanent magnet between an embedded motor to which ay is applied and a conventional embedded motor.

In the embedded motor to which the halbach magnet array of the present invention is applied, the amount of generated magnetic flux is larger than that of the conventional embedded motor, and the magnetic flux is concentrated at the pole center. In addition, it is possible to cover the loss due to the magnetic leakage generated in the vicinity of both ends of the permanent magnet and the outer periphery of the rotor.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

The following embodiments of the present invention relate to a four-pole permanent magnet embedded motor, but the number of poles is not limited.

(Embodiment 1) In FIG. 1, a rotor 3
The rotor core 3a made of a high magnetic permeability material is embedded with four sets of permanent magnets 1 arranged so that N poles and S poles are alternately arranged, and is fixed to the rotor shaft 4. Each permanent magnet 1 is formed in a circular arc shape protruding toward the center of the rotor, and an auxiliary magnet 2 having a magnetic pole in a direction perpendicular to the magnetic pole direction of the main magnet is disposed at each end.

FIG. 2 shows the relationship between the length l of the auxiliary magnets disposed at both ends of the main magnet and the generated magnetic flux. FIG.
As shown in the figure, Halbach magne
Does not exhibit the effect of the t array method. Further, if the length of the auxiliary magnet is long, the amount of magnetic flux generated by the main magnet decreases. Thus, the length of the auxiliary magnets disposed at both ends of the main magnet is determined by the opening angle θ of the permanent magnets constituting each pole.
0.05 to 0.2 times is suitable for

In the case of driving with a rectangular wave, it is appropriate that the length of the main magnet is 0.9 to 1.1 times the energizing section.

The stator 5 has a predetermined number of teeth 6, and a stator winding (not shown) is arranged between the teeth 6. When an alternating current is applied to the stator winding, a rotating magnetic flux is generated, and the rotor 3 is driven to rotate by the rotating magnetic flux.

FIG. 3 shows an example in which the permanent magnet embedded in the rotor is flat, and FIG. 4 shows an example in which the permanent magnet is protruded toward the outer periphery of the rotor.

(Embodiment 2) In FIG. 5, the permanent magnets 1 constituting each pole are divided into a plurality of magnets, and the magnets are arranged so that the magnetic flux is concentrated at the pole center.

FIG. 6 shows an example in which the permanent magnet embedded in the rotor is flat, and FIG. 7 shows an example in which the permanent magnet is protruded toward the outer periphery of the rotor.

(Embodiment 3) In FIG. 8, an auxiliary magnet having a magnetic pole perpendicular to the magnetic pole direction of the main magnet 1 is arranged between the poles.

FIG. 9 shows an example in which the permanent magnet embedded in the rotor is a flat plate, and FIG. 10 shows an example in which the permanent magnet is convex toward the outer periphery of the rotor.

[0025]

According to the present invention, the magnetic flux generated by the permanent magnet can be increased as compared with a conventional motor in which a permanent magnet magnetized in one direction is embedded, so that more magnet torque is used. be able to.

Further, it is possible to cover the amount of leakage magnetic flux generated at the portions near both ends of the permanent magnet and the outer periphery of the rotor.

Further, when a rotor that generates the same output as the conventional one is constructed, the portions of both ends of the permanent magnet close to the outer periphery of the rotor can be more effectively saturated. From the rotor to the outer periphery of the rotor can be widened, so that higher-speed rotation than before becomes possible.

As a result, a high-torque, high-output, high-rotation motor can be provided.

[Brief description of the drawings]

FIG. 1A is a configuration diagram of a permanent magnet embedded motor showing an embodiment of the present invention. FIG.

FIG. 2 is a graph showing generated magnetic flux characteristics according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 4 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 5 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 6 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 7 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 8 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 9 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 10 is a configuration diagram of a permanent magnet embedded motor showing another embodiment of the present invention.

FIG. 11 Halbach Magnet Array explanatory diagram

FIG. 12 is a graph showing a gap magnetic flux density characteristic.

FIG. 13 is a configuration diagram of a conventional permanent magnet embedded motor.

FIG. 14 is an enlarged view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Permanent magnet 1a Main magnet 2 Auxiliary magnet 3 Rotor 3a Rotor core 4 Rotor shaft 5 Stator 6 Teeth

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyuki Kiriyama 1006 Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A permanent magnet having a rotor in which a plurality of permanent magnets are embedded in a rotor body made of a high magnetic permeability material in a rotor axial direction, and adjacent poles are divided by a rotor core. In the magnet-embedded motor, the permanent magnets constituting the respective poles are characterized in that a central main magnet and auxiliary magnets having magnetic poles perpendicular to the magnetic pole direction of the main magnet are arranged at both ends thereof. motor. 2. The permanent magnet embedded motor according to claim 1, wherein the length of the auxiliary magnet is 0.05 to 0.2 times the opening angle of the permanent magnet constituting each pole. 3. The permanent magnet embedded motor according to claim 1, wherein the length of the main magnet is 0.9 to 1.1 times the energizing section in the rectangular wave drive. 4. The permanent magnet embedded motor according to claim 1, wherein the main magnet is divided into a plurality of magnets, and the magnetic poles are arranged so that magnetic fluxes are concentrated at the pole centers. 5. A permanent magnet having a rotor in which a plurality of permanent magnets are embedded in a rotor body made of a high magnetic permeability material in a rotor axial direction and adjacent poles are divided by a rotor core. A permanent magnet embedded motor in which an auxiliary magnet having a magnetic pole perpendicular to the magnetic pole direction of the permanent magnet is disposed between the poles. 6. The permanent magnet embedded motor according to claim 1, wherein the permanent magnet is formed in an arc shape convex toward the center of the rotor. 7. The permanent magnet embedded motor according to claim 1, wherein the permanent magnet has a flat plate shape. 8. The motor with embedded permanent magnets according to claim 1, wherein the permanent magnet is formed in a circular arc shape protruding toward the outer periphery of the rotor.