KR101744412B1 - Permanent Magnet Motor for reducing q-axis inductance and rotor using the same - Google Patents

Permanent Magnet Motor for reducing q-axis inductance and rotor using the same Download PDF

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KR101744412B1
KR101744412B1 KR1020150146127A KR20150146127A KR101744412B1 KR 101744412 B1 KR101744412 B1 KR 101744412B1 KR 1020150146127 A KR1020150146127 A KR 1020150146127A KR 20150146127 A KR20150146127 A KR 20150146127A KR 101744412 B1 KR101744412 B1 KR 101744412B1
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South Korea
Prior art keywords
rotor
magnetic flux
permanent magnet
magnet motor
permanent magnets
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KR1020150146127A
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Korean (ko)
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KR20170045961A (en
Inventor
이주
설현수
이재준
이재광
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한양대학교 산학협력단
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)

Abstract

A permanent magnet motor for reducing q-axis inductance and a rotor included therein are provided. The disclosed permanent magnet motor includes a stator; And a plurality of pole pieces disposed between each of the plurality of permanent magnets and a plurality of magnetic flux barriers located in each of the plurality of pole pieces, Wherein the plurality of magnetic flux barriers are located in a pole piece in the outer surface direction of the rotor.

Description

[0001] The present invention relates to a permanent magnet motor for reducing q-axis inductance and a rotor included therein,

Embodiments of the present invention relate to a permanent magnet motor that reduces q-axis inductance and a rotor included therein.

Permanent Magnet Motor In particular, a magnetic flux concentrating permanent magnet motor is an electric motor that removes a brush structure from a DC motor and performs rectification electronically.

1 is a plan view of a conventional magnetic flux concentrating permanent magnet motor.

Referring to FIG. 1, a conventional magnetic flux concentrating permanent magnet motor 100 includes a stator 110 and a rotor 120.

The stator 110 refers to a stationary portion of the rotating machine, and comprises an iron core for supporting the windings and a frame for attaching the iron core.

The rotor 120 rotates inside the stator 110 and includes a plurality of permanent magnets 121. The plurality of permanent magnets 121 are radially arranged about the rotational axis of the rotor 120.

The conventional magnetic flux concentrating permanent magnet motor 100 detects the position of the permanent magnet 121, that is, the position of the rotor 120 by an electronic sensor such as a Hall sensor (magnetic pole detecting sensor) And a current is supplied to the coil to generate a torque. An armature winding is provided in the rotor 120 and an armature winding is provided in the stator 110 and the current direction of the winding is determined using the Hall sensor so as to have the same characteristics as the brush type. The armature current is supplied so that the magnetic field generated in the armature winding is always at 90 degrees with the fixed magnetic pole provided in the rotor.

On the other hand, when high-speed operation is required, the frequency of the conventional motor 100 becomes high, and the voltage reaches the limit value, so that the current can not be applied any more. For this reason, when the motor 100 is operated at a higher speed, a method of increasing the d-axis current of the motor 100 to reduce the field magnetic flux through the inverse magnetic field to suppress the rise of the terminal voltage is used,

Specifically, the weak field control method refers to a driving method in which the operating area is secured at a higher speed by controlling the flux of the rotor 120 by adjusting the phase angle of the current by converting the three-phase current to the d and q axes . Here, the q-axis current is classified into the current that generates the torque of the motor 100, and the d-axis current is classified into the current that suppresses the field magnetic flux generated in the rotor 120. When the rotor 120 enters the high speed region, the operation speed is limited due to the increase of the organic electromotive force due to the magnetic flux of the rotor 120. At this time, the current phase angle is increased to increase the d- Thereby ensuring a high-speed operation region.

However, in the conventional weak field control method, when the field operation is weakly performed in the high speed region, the current phase angle becomes high, and the d-axis current which is the current for suppressing the magnetic flux in the entire current increases. the q-axis current decreases. As a result, there is a problem that output is limited.

In order to solve the problems of the prior art as described above, the present invention proposes a permanent magnet motor for increasing q-axis current by reducing q-axis inductance and a rotor included therein.

Other objects of the invention will be apparent to those skilled in the art from the following examples.

To achieve the above object, according to a preferred embodiment of the present invention, there is provided a permanent magnet motor comprising: a stator; And a plurality of pole pieces disposed between each of the plurality of permanent magnets and a plurality of magnetic flux barriers located in each of the plurality of pole pieces, Wherein the plurality of magnetic flux barriers are located on a pole piece in the outer surface direction of the rotor.

The rotor may further include a plurality of bridges coupled to each of the plurality of pole pieces, wherein the plurality of magnetic flux barriers may be positioned radially about the corresponding bridges.

Wherein the plurality of permanent magnets are radially arranged about the rotation axis of the rotor Can be located.

The plurality of magnetic flux barriers may be arranged symmetrically with respect to a center line between the permanent magnets with the bridge as a center.

The magnitude of the plurality of magnetic flux barriers may gradually increase toward the permanent magnet side with respect to the center line between the permanent magnets with the bridge as a center.

According to another embodiment of the present invention, there is provided a cylindrical rotor used in a permanent magnet motor, comprising: a plurality of permanent magnets; A plurality of pole pieces disposed between each of the plurality of permanent magnets; And a plurality of magnetic flux barriers located in each of the plurality of pole pieces, wherein the plurality of magnetic flux barriers are located on a pole piece in the outer surface direction of the rotor.

The permanent magnet motor according to the present invention and the rotor included therein have an advantage that the q-axis inductance can be reduced and the q-axis current can be increased.

1 is a plan view of a conventional magnetic flux concentrating permanent magnet motor.
2 is a diagram showing a schematic configuration of a permanent magnet motor according to one embodiment of the present invention.
Figure 3 shows a top view of a portion of a rotor in accordance with an embodiment of the present invention.
4 is a diagram showing the d, q-axis magnetic path of the magnetic flux concentration type permanent magnet motor
5 shows the formation of a rotor having the same magnitude of the magnetic flux barrier.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In this specification, the terms "comprising ", or" comprising "and the like should not be construed as necessarily including the various elements or steps described in the specification, Or may be further comprised of additional components or steps. Also, the terms "part," " module, "and the like described in the specification mean units for processing at least one function or operation, which may be implemented in hardware or software or a combination of hardware and software .

Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

2 is a diagram showing a schematic configuration of a permanent magnet motor according to one embodiment of the present invention.

Referring to FIG. 2, the permanent magnet motor 200 according to an embodiment of the present invention may be a magnetic flux concentrating permanent magnet motor, and includes a stator 210 and a rotor 220.

2 (a) is a plan view of the permanent magnet electric motor 200, and FIG. 2 (b) is a plan view of the rotor 220, respectively.

The stator 210 is a stationary portion of the permanent magnet electric motor 200, and comprises a core for supporting the coil and a frame for attaching the core.

The rotor 220 rotates inside the stator 210 and is cylindrical and has a plurality of permanent magnets 221, a plurality of pole pieces 222, and a plurality of pole pieces 222, A plurality of flux barriers 232 and a plurality of bridges 224,

The plurality of permanent magnets 221 are radially positioned about the rotational axis of the rotor 220 on a top view of the rotor 220.

Each of the plurality of pole pieces 222 is a total magnetic pole portion positioned between one permanent magnet and another permanent magnet adjacent thereto.

A plurality of magnetic flux barriers 223 are located in each of the plurality of pole pieces 222. The magnetic flux barrier 223 serves to increase the q-axis magnetoresistance to reduce the q-axis inductance.

A plurality of magnetic flux barriers 223 in each pole piece 222 are disposed on the outermost portion of the pole piece 222 in the direction of the outer surface of the rotor 220, Can be located.

Each of the plurality of bridges is connected to each of the plurality of pole pieces 222 and connects the front end of the rotor 220 and the base of the rotor 220.

According to one embodiment of the present invention, a plurality of magnetic flux barriers 223 may be radially positioned about a bridge 223 (hereinafter referred to as "corresponding bridge ") connected to the disposed pole piece 222 This will be described in more detail as follows.

Figure 3 illustrates a top view of a portion of the rotor 220 in accordance with one embodiment of the present invention.

FIG. 3 is a cross-sectional view of the pole piece 320 and the pole piece 320, which are positioned between the i-th permanent magnet 311 and the i + 1-th permanent magnet 312 among the plurality of permanent magnets 221, A portion of the rotor 220 including a plurality of magnetic flux barriers 340 located on the rotor.

Referring to FIG. 3, a plurality of magnetic flux barriers 340 are radially positioned about a bridge 330.

According to an embodiment of the present invention, the plurality of magnetic flux barriers 330 may be arranged symmetrically with respect to the center line between the permanent magnets 311 and 312 with the bridge 330 as a center.

According to an embodiment of the present invention, the magnitude of a plurality of magnetic flux barriers decreases toward the permanent magnets 311 and 312 on the basis of the center line between the permanent magnets 311 and 312 around the bridge 340 Can be gradually increased.

For example, the first magnetic flux barrier 331 located on the center line is smaller than the second magnetic flux barrier 332, and the second magnetic flux barrier 332 is smaller than the third magnetic flux barrier 333. That is, the magnitudes of the five magnetic flux barriers 331, 332, 333, 334 and 335 with reference to the right side of the center line are the same as those of the first magnetic flux barrier 331, the second magnetic flux barrier 332, ) &Lt; fourth magnetic flux barrier 334 < fifth magnetic flux barrier 335 &quot;. Also, the left side of the center line has the same magnitude relation of the magnetic flux barrier.

With such a configuration, the present invention can further reduce the q-axis inductance and further use a q-axis current that is a current for generating torque by operating at a current phase angle smaller than a current phase angle that operates at the same speed. As a result, it is possible to operate at the same speed even at a lower current phase angle as compared with the conventional permanent magnet motor, and the margin of the q-axis current is further secured, so that the torque at high speed is advantageously increased.

4 and 5, the permanent magnet motor 200 according to the present invention will be described in more detail.

4 is a diagram showing the d, q-axis magnetic path of the magnetic flux concentration type permanent magnet motor

Generally, the permanent magnet motor has a speed limit due to the voltage limit. Then, the phase voltage of the permanent magnet motor

Figure 112015101701516-pat00001
) Is the speed
Figure 112015101701516-pat00002
) And no load chain
Figure 112015101701516-pat00003
), A current phase angle (
Figure 112015101701516-pat00004
Is determined by the d-axis inductance (L d ) and the q-axis inductance (L q ). The phase voltage of the permanent magnet motor (
Figure 112015101701516-pat00005
) Is expressed by the following equation (1).

Figure 112015101701516-pat00006

Permanent magnet electric motor 200 according to the present invention is responsible for decreases the q-axis inductance (L q), by placing the flux barriers (224, 340) to the q-axis character.

Figure 5 shows the formation of a rotor having the same magnitude of the magnetic flux barrier.

When the q-axis inductance ( Lq ) becomes smaller, the same current phase angle (

Figure 112015101701516-pat00007
) To the phase voltage (
Figure 112015101701516-pat00008
) Becomes lower, and the phase voltage (
Figure 112015101701516-pat00009
The torque T of the permanent magnet motor becomes large because the torque partial current i q can be increased. The torque T of the permanent magnet motor is expressed by the following equation (2).

Figure 112015101701516-pat00010

At this time, the rotor 220 having a magnetic flux barrier (224.340) according to the invention is effective in reducing a q-axis inductance (L q) than the rotor shown in Fig.

Table 1 is a table showing the conventional rotor shown in Fig. 1, the rotor shown in Fig. 5, the rotor 220 according to the present invention, the results of the finite element analysis and the motor parameters.

1 5 Invention Speed [RPM] 21000 Torque [mNm] 343 352 359 Phase voltage [V] 160.9 160.7 160.7 Current phase angle [degE] 81.7 80.7 80.3 d-axis inductance Ld [mH] 26.5 25.6 25.3 q-axis inductance (Lq) [mH] 37.7 34.6 33.3 d axis current (id) [A] -3.94 -3.93 -3.93 q axis current (iq) [A] 0.59 0.64 0.67

Referring to Table 1, it can be seen that the d-axis inductance is almost the same but the q-axis inductance is decreased at the same speed. As a result, the q-axis current component as the torque current can be further used. Also, it can be seen that the rotor 220 according to the present invention has a greater q-axis inductance reduction than the rotor according to FIG. 5 and thus has a higher torque.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and limited embodiments and drawings. However, it should be understood that the present invention is not limited to the above- Various modifications and variations may be made thereto by those skilled in the art to which the present invention pertains. Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (8)

In the permanent magnet motor,
Stator; And
A plurality of pole pieces disposed between each of the plurality of permanent magnets; a plurality of bridges connected to each of the plurality of pole pieces; and a plurality of magnetic flux barrier And a rotor rotatable within the stator,
Wherein each of the plurality of permanent magnets is radially positioned about a rotation axis of the rotor and the plurality of magnetic flux barriers are positioned radially from a pole piece in the outer surface direction of the rotor about a corresponding bridge,
And the magnitude of the plurality of magnetic flux barriers gradually increases in a direction toward the permanent magnet with respect to a center line between the permanent magnets with the bridge as a center. delete delete The method according to claim 1,
Wherein the plurality of magnetic flux barriers are arranged symmetrically with respect to a center line between the permanent magnets with the bridge as a center. delete In a cylindrical rotor used in a permanent magnet motor,
A plurality of permanent magnets positioned radially around the rotation axis of the rotor;
A plurality of pole pieces disposed between each of the plurality of permanent magnets;
A plurality of bridges coupled to each of the plurality of pole pieces; And
A plurality of magnetic flux barriers located in each of the plurality of pole pieces,
Wherein the plurality of magnetic flux barriers are positioned radially from the pole piece in the direction of the outer surface of the rotor about the corresponding bridge,
And the magnets of the plurality of magnetic flux barriers gradually increase in the direction toward the permanent magnet with respect to a center line between the permanent magnets with the bridge as a center. delete delete
KR1020150146127A 2015-10-20 2015-10-20 Permanent Magnet Motor for reducing q-axis inductance and rotor using the same KR101744412B1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005094968A (en) * 2003-09-19 2005-04-07 Toshiba Kyaria Kk Permanent-magnet electric motor
JP2006340487A (en) * 2005-06-01 2006-12-14 Denso Corp Brushless motor
JP2008187778A (en) * 2007-01-29 2008-08-14 Mitsubishi Electric Corp Rotator for permanent magnet embedded motor, blower, and compressor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005094968A (en) * 2003-09-19 2005-04-07 Toshiba Kyaria Kk Permanent-magnet electric motor
JP2006340487A (en) * 2005-06-01 2006-12-14 Denso Corp Brushless motor
JP2008187778A (en) * 2007-01-29 2008-08-14 Mitsubishi Electric Corp Rotator for permanent magnet embedded motor, blower, and compressor

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