CN113541349A - Sine wave rotor designed based on outer rotor iron core eccentric structure - Google Patents

Sine wave rotor designed based on outer rotor iron core eccentric structure Download PDF

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Publication number
CN113541349A
CN113541349A CN202110624911.1A CN202110624911A CN113541349A CN 113541349 A CN113541349 A CN 113541349A CN 202110624911 A CN202110624911 A CN 202110624911A CN 113541349 A CN113541349 A CN 113541349A
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Prior art keywords
rotor
iron core
eccentric
outer rotor
sine wave
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CN113541349B (en
Inventor
韩坤
苏森
王志强
陈胜林
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Anhui Huachi Kinetic Energy Technology Co Ltd
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Anhui Huachi Kinetic Energy Technology Co Ltd
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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
    • H02K1/2786—Outer rotors
    • 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
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K16/00—Machines with more than one rotor or stator
    • H02K16/02—Machines with one stator and two or more rotors
    • 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
    • H02K21/02—Details
    • H02K21/021—Means for mechanical adjustment of the excitation flux
    • H02K21/028—Means for mechanical adjustment of the excitation flux by modifying the magnetic circuit within the field or the armature, e.g. by using shunts, by adjusting the magnets position, by vectorial combination of field or armature sections
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
    • H02K2201/03—Machines characterised by aspects of the air-gap between rotor and stator
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
    • H02K2201/06—Magnetic cores, or permanent magnets characterised by their skew
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
    • H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information

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

Abstract

The invention relates to the technical field of motors, and particularly discloses a sine wave rotor designed based on an outer rotor iron core eccentric structure; the permanent magnet motor comprises an outer rotor iron core, permanent magnets, a stator, an inner rotor iron core and a rotor shaft, wherein the outer rotor iron core and the inner rotor iron core are respectively arranged at the outer end and the outer end of the rotor shaft; the invention adopts the outer rotor iron core which is specially designed based on the eccentric circular structure, so that the thickness edge of the radial air gap of the motor is not uniform, the change of the radial thickness of the air gap is more reasonable, the air gap flux density waveform of the motor is improved, the harmonic content in the air gap magnetic field is reduced, the air gap magnetic field is close to a sine wave, the back electromotive force waveform of the hollow cup type motor is improved, the torque pulsation is reduced, and the motor performance is improved.

Description

Sine wave rotor designed based on outer rotor iron core eccentric structure
Technical Field
The invention relates to the technical field of motors, and particularly discloses a sine wave rotor designed based on an outer rotor iron core eccentric structure.
Background
The traditional permanent magnet synchronous motor and sine wave motor are mostly applied to high-rotating-speed occasions and need high speed regulation precision, so that the traditional permanent magnet synchronous motor and sine wave motor are mostly driven and controlled by sine wave phase current, and the sine wave phase current needs to interact with sine wave counter electromotive force so as to reduce electromagnetic torque pulsation. In the traditional hollow cup type permanent magnet motor, the harmonic content of 3, 5 and 7 times in the waveform of the back electromotive force is large, so that the motor generates electromagnetic torque pulsation, and the performance and the efficiency of the motor are influenced. The main reason that the waveform of the back electromotive force of the hollow cup type permanent magnet motor has higher harmonic content is that the sine type of the waveform of the air gap magnetic field of the motor is poorer, and more odd harmonics are mixed, so that the air gap magnetic field of the motor is close to a trapezoid, and the harmonic content of the waveform of the back electromotive force is higher. Therefore, the optimization of the motor structure and the reduction of the harmonic content of the air-gap magnetic field waveform are of great importance to enable the air-gap magnetic field waveform to be close to a sine wave.
The invention patent with application number 2010101099694 discloses a stator-free iron core permanent magnet synchronous motor which mainly comprises a rotor shaft, an inner rotor iron core, a magnetic isolation block, a hollow cup stator, a Halbach permanent magnet and an outer rotor iron core, wherein the magnetic isolation block is embedded in the inner rotor iron core and forms an inner rotor component part together with the inner rotor iron core, the outer rotor iron core and the permanent magnet are connected to the rotor shaft, the Halbach permanent magnet is attached to the outer rotor iron core, and the hollow cup stator is fixed on a machine shell. The permanent magnetic circuit forms a closed loop through the inner rotor iron core, the magnetic air gap, the Halbach permanent magnet and the outer rotor iron core. The hollow cup stator structure can be used in the design of a permanent magnet synchronous motor, so that the inner rotor core and the outer rotor core synchronously rotate along with the permanent magnet, loss can not be generated in the cores, meanwhile, the hollow cup stator enables the stator to be a tooth-slot-free structure, the cogging torque and tooth harmonic can be eliminated, but the radial air gap magnetic resistance is consistent due to uniform radial thickness of an air gap, the distribution of an air gap magnetic field is influenced, the air gap magnetic field harmonic content is large, and the sine performance is poor; in addition, because the permanent magnets are in direct contact with each other, interpolar magnetic flux leakage is generated, and the performance of the motor is influenced. Therefore, aiming at the defects of large air gap magnetic field harmonic content and poor sine performance in the existing permanent magnet synchronous motor and sine wave motor, the technical problem to be solved is to design a rotor with optimized structure, wherein the rotor can reduce the air gap magnetic field waveform harmonic content and make the air gap magnetic field waveform approach to the sine wave.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the sine wave rotor overcomes the defects of the prior art, can be used for an outer rotor core eccentric structure in a permanent magnet synchronous motor and a sine wave motor, and solves the problem that the difference between the air gap magnetic field waveform and the sine wave is large.
The invention is realized by the following technical scheme:
a sine wave rotor designed based on an eccentric structure of an outer rotor iron core comprises the outer rotor iron core, permanent magnets, a stator, an inner rotor iron core and a rotor shaft, wherein the radial outer side of the outer rotor iron core is arranged at the outer end of the rotor shaft, the radial inner side of the inner rotor iron core is arranged at the inner end of the rotor shaft, a plurality of tile-shaped permanent magnets are alternately arranged along the radial outer side of the inner rotor iron core, the magnetizing directions of two adjacent permanent magnets are opposite, the outer contour of the outer rotor iron core is circular, the inner contour of the outer rotor iron core is formed by a plurality of circumferential inwards-convex eccentric arcs, the number of the eccentric arcs is the same as that of the permanent magnets, the positions of the eccentric arcs correspond to the permanent magnets one by one, an annular air gap is formed between the radial inner side of the outer rotor iron core and the permanent magnets, and the stator is arranged in the annular air gap and fixed on a machine shell;
the circular outline of the outer rotor iron core, the inner outline and the outer outline of the permanent magnet and the inner outline and the outer outline of the inner rotor iron core are arranged concentrically, the concentric point is the geometric center of the rotor, two end points of the eccentric arc are positioned on the extension line of the connecting line of the two side edges of the corresponding permanent magnet and the geometric center of the rotor, the circle center of the eccentric arc is positioned on the reverse extension line of the connecting line of the middle point of the corresponding permanent magnet and the geometric center of the rotor, and the circle center of the eccentric arc is positioned on the radial outer side of the outer rotor iron core.
As a further provision of the above solution, the distance from the midpoint of the eccentric arc to the geometric center of the rotor is
Figure DEST_PATH_IMAGE002
And satisfies the relation:
Figure DEST_PATH_IMAGE004
wherein
Figure DEST_PATH_IMAGE006
Is the radius of the outer contour of the inner rotor iron core,
Figure DEST_PATH_IMAGE008
is the thickness of the permanent magnet.
As a further arrangement of the above solution, the radius of the eccentric arc is
Figure DEST_PATH_IMAGE010
And satisfies the relation:
Figure DEST_PATH_IMAGE012
wherein
Figure DEST_PATH_IMAGE014
The number of pole pairs of the motor is shown.
The magnetic isolation device is characterized by further comprising tile-shaped magnetic isolation blocks which are equal to the permanent magnets in number, the magnetic isolation blocks are arranged between every two adjacent permanent magnets, and two end points of the eccentric arc are located on an extension line of a connecting line between the middle point of tile-shaped edges of the magnetic isolation blocks on the two sides of the corresponding permanent magnets and the geometric center of the rotor.
As a further arrangement of the above scheme, the tile-shaped inner diameter of the magnetic isolation block is
Figure DEST_PATH_IMAGE016
And satisfies the relation:
Figure DEST_PATH_IMAGE018
(ii) a The tile-shaped outer diameter of the magnetic isolation block is
Figure DEST_PATH_IMAGE020
And satisfies the relation:
Figure DEST_PATH_IMAGE022
(ii) a Wherein
Figure DEST_PATH_IMAGE024
Is the radius of the outer contour of the inner rotor iron core,
Figure DEST_PATH_IMAGE026
is the thickness of the permanent magnet.
As a further arrangement of the above scheme, the tile-shaped opening angle of the magnetic isolation block is
Figure DEST_PATH_IMAGE028
And satisfies the relation:
Figure DEST_PATH_IMAGE030
the tile-shaped opening angle of the permanent magnet
Figure DEST_PATH_IMAGE032
Satisfy the relation
Figure DEST_PATH_IMAGE034
Wherein
Figure DEST_PATH_IMAGE036
The number of pole pairs of the motor is shown.
As a further arrangement of the above solution, the radius of the eccentric arc is
Figure DEST_PATH_IMAGE038
And satisfies the relation:
Figure DEST_PATH_IMAGE040
wherein
Figure DEST_PATH_IMAGE042
The coefficient of the magnetic isolation block satisfies the relation:
Figure DEST_PATH_IMAGE044
。
as a further arrangement of the above solution, the distance between the center of the eccentric arc and the geometric center of the rotor is an eccentricity value
Figure DEST_PATH_IMAGE046
And satisfies the relation:
Figure DEST_PATH_IMAGE048
。
as a further configuration of the above aspect, the radius of the circular outer contour of the outer rotor core is
Figure DEST_PATH_IMAGE050
And satisfies the relation:
Figure DEST_PATH_IMAGE052
。
as a further configuration of the above aspect, the number of the eccentric arcs on the outer rotor core is
Figure DEST_PATH_IMAGE054
And satisfies the relation:
Figure DEST_PATH_IMAGE056
wherein
Figure DEST_PATH_IMAGE058
The number of pole pairs of the motor is shown.
Has the advantages that:
compared with the prior art, the invention has the advantages that: the invention adopts the outer rotor iron core which is specially designed based on the eccentric circular structure, so that the thickness edge of the radial air gap of the motor is not uniform, the change of the radial thickness of the air gap is more reasonable, the air gap flux density waveform of the motor is improved, the harmonic content in the air gap magnetic field is reduced, the air gap magnetic field is close to a sine wave, the back electromotive force waveform of the hollow cup type motor is improved, the torque pulsation is reduced, and the motor performance is improved. Meanwhile, compared with the traditional hollow cup permanent magnet motor, the permanent magnet is attached to the inner rotor iron core, so that the radius is reduced, and the permanent magnet material is saved; and the permanent magnets are separated by the magnetic separation blocks, so that magnetic loops generated on the sides of the permanent magnets are reduced, interpolar magnetic leakage is reduced, and the motor performance is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic structural view of example 1 of the present invention;
FIG. 2 is a partial schematic structural view of embodiment 1 of the present invention;
FIG. 3 is a schematic diagram showing the comparison between the air gap field of the coreless permanent magnet synchronous motor of embodiment 1 of the present invention and that of the conventional coreless motor;
FIG. 4 is a schematic structural view of example 2 of the present invention;
FIG. 5 is a partial structural view of embodiment 2 of the present invention;
fig. 6 is a schematic diagram showing the comparison of the air gap field of the coreless sine wave motor of embodiment 2 of the present invention with that of the conventional coreless motor.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The terms "mounted," "disposed," "provided," "connected," "sleeved," "laid," and the like are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will now be described in detail with reference to the accompanying figures 1-6, in conjunction with an illustrative embodiment.
Example 1
Embodiment 1 discloses a sine wave rotor designed based on an outer rotor core eccentric structure, which is used in a hollow cup type permanent magnet motor. Referring to fig. 1 and 2, which include an outer rotor core 1, a permanent magnet 2, a coreless stator 3, an inner rotor core 4, and a rotor shaft 5, the outer rotor core 1 and the inner rotor core 4 are both fixedly coupled to the rotor shaft 5 such that the outer rotor core 1 and the inner rotor core 4 rotate together with the rotor shaft 5. When the permanent magnet synchronous motor is arranged, the radial outer side of the outer rotor iron core 1 is arranged at the outer end of the rotor shaft 5, the radial inner side of the inner rotor iron core 4 is arranged at the inner end of the rotor shaft 5, a plurality of tile-shaped permanent magnets 2 are alternately arranged on the outer circular surface of the inner rotor iron core 4, and the magnetizing directions of the two adjacent permanent magnets 2 are opposite. The thickness of the tile-shaped permanent magnet 2 is determined according to the actual working requirement of the motor, and the number of the tile-shaped permanent magnets is determined according to the number of pole pairs.
The inner rotor core 4 is circular ring shaped. The outer contour of the outer rotor iron core 1 is circular, the radius of the outer contour is determined by the actual requirement of the motor, the inner contour of the outer rotor iron core 1 is formed by a group of eccentric arcs which are convex inwards, the number of the eccentric arcs is equal to that of the permanent magnets 2, and the positions of the eccentric arcs correspond to the permanent magnets 2 one by one. Specifically, the number of the eccentric arcs on the outer rotor core 1 is
Figure DEST_PATH_IMAGE060
And satisfies the relation:
Figure DEST_PATH_IMAGE062
wherein
Figure DEST_PATH_IMAGE064
As poles of electric machinesLogarithm. An air gap of the motor is formed between the radial inner side of the outer rotor core 1 and the permanent magnet 2, the hollow cup stator 3 is arranged in the air gap and is fixed on the machine shell, and magnetic flux generated by the permanent magnet 2 forms a closed loop through the outer rotor core 1, the inner rotor core 4 and the air gap between the outer rotor core 1 and the inner rotor core 4.
When the motor is arranged, the circular outline of the outer rotor core 1, the inner outline of the tile-shaped permanent magnet 2 and the inner outline of the inner rotor core 4 are concentrically arranged, and the concentric point is used as the geometric center of the motor (also the geometric center of the rotor). Two end points of each eccentric arc are arranged on an extension line of a connecting line of two side edges of the corresponding permanent magnet 2 and the geometric center of the motor, the circle center of each eccentric arc is arranged on a reverse extension line of a connecting line of the arc-shaped edge of the corresponding permanent magnet 2 and the geometric center of the motor, and the circle center of each eccentric arc is arranged on the radial outer side of the outline of the outer rotor core 1.
As shown in fig. 2, point O is the geometric center of the motor; A. b, two points are two end points of the eccentric arc, O' point is the center of the eccentric arc, and H point is the middle point of the eccentric arc;
Figure DEST_PATH_IMAGE066
is the thickness of the permanent magnet;
Figure DEST_PATH_IMAGE068
which is the radius of the outer contour of the inner rotor core 4,
Figure DEST_PATH_IMAGE070
is the radius of the eccentric arc,
Figure DEST_PATH_IMAGE072
the distance from the middle point of the eccentric arc to the geometric center of the motor,
Figure DEST_PATH_IMAGE074
the eccentric value is the distance between the center of the eccentric arc and the geometric center of the motor;
Figure DEST_PATH_IMAGE076
the radius of the outer contour of the outer rotor iron core.
The two end points A, B of the eccentric arc are on the extension line of the connecting line of the two sides of the corresponding permanent magnet 2 and the geometric center O of the motor, that is, the two sides of the permanent magnet 2 corresponding to the eccentric arc are on the line segments OA and OB.
The circle center of the eccentric arc is on the reverse extension line of the connecting line of the arc-shaped center point of the corresponding permanent magnet 2 and the geometric center of the motor, namely, the O 'point is positioned on the extension line of the line segment OH and positioned outside the radial outer side of the outline of the outer rotor iron core 1, namely, the connecting line O' H of the center point of the eccentric arc and the circle center of the eccentric arc passes through the radial outline of the outer rotor iron core 1.
Meanwhile, the sine wave rotor designed based on the outer rotor core eccentric structure meets the following design regarding dimensions when being arranged:
1) the distance from the middle point of the eccentric arc to the geometric center of the motor is
Figure DEST_PATH_IMAGE078
And satisfies the relation:
Figure DEST_PATH_IMAGE080
in the formula
Figure DEST_PATH_IMAGE082
Is the radius of the outer contour of the inner rotor iron core,
Figure DEST_PATH_IMAGE084
is the thickness of the permanent magnet;
2) the radius of the eccentric arc is
Figure DEST_PATH_IMAGE086
And satisfies the relation:
Figure DEST_PATH_IMAGE088
in the formula
Figure DEST_PATH_IMAGE090
The number of pole pairs of the motor is;
3) the distance between the center of the eccentric arc and the geometric center of the motor is an eccentric value
Figure DEST_PATH_IMAGE092
And satisfies the relation:
Figure DEST_PATH_IMAGE094
。
4) the radius of the circular outline of the outer rotor iron core is
Figure DEST_PATH_IMAGE096
And satisfies the relation:
Figure DEST_PATH_IMAGE098
。
this embodiment 1 uses an inner rotor core outer diameter
Figure DEST_PATH_IMAGE100
Is 52mm, and the thickness of the permanent magnet
Figure DEST_PATH_IMAGE102
6mm, number of pole pairs
Figure DEST_PATH_IMAGE104
For example, the hollow cup type permanent magnet synchronous motor designed based on the eccentric structure of the outer rotor core is 6, and the outer rotor core is designed as follows:
is composed of
Figure DEST_PATH_IMAGE106
Calculating the distance from the middle point of the eccentric arc to the geometric center of the motor
Figure 470532DEST_PATH_IMAGE108
Satisfy the requirement of
Figure 918831DEST_PATH_IMAGE110
In order to facilitate the processing,
Figure 229726DEST_PATH_IMAGE112
preferably 65 mm;
is composed of
Figure 890515DEST_PATH_IMAGE114
Determining the half of the eccentric arcDiameter of a pipe
Figure 236045DEST_PATH_IMAGE116
Satisfy the requirement of
Figure 589666DEST_PATH_IMAGE118
In order to facilitate the processing,
Figure 387858DEST_PATH_IMAGE120
preferably 30 mm;
is composed of
Figure 852337DEST_PATH_IMAGE122
Calculating an eccentricity value
Figure 52375DEST_PATH_IMAGE124
Is 95 mm;
is composed of
Figure 576897DEST_PATH_IMAGE126
Determining the radius of the circular outer side of the outer rotor core
Figure 596805DEST_PATH_IMAGE128
Satisfy the requirement of
Figure 862046DEST_PATH_IMAGE130
In order to facilitate the processing,
Figure 916590DEST_PATH_IMAGE132
preferably 106 mm.
The motor parameters of the traditional hollow cup type motor are that the outer diameter of an eccentric outer rotor is 106mm, the inner diameter is 65mm, and the number of pole pairs is
Figure 612013DEST_PATH_IMAGE134
6 pairs, the outer diameter of the inner rotor is 52mm, the outer diameter of the permanent magnet is 58mm, the thickness is 6mm, and the inner diameter is 52 mm.
Compared with the traditional hollow cup type motor, the air gap magnetic field of the hollow cup type permanent magnet synchronous motor designed based on the outer rotor core eccentric structure is closer to a sine wave. Referring to FIG. 3, the Total Harmonic Distortion (THD) is introduced to evaluate the sinusoidality of the air-gap magnetic field waveformFourier decomposition transform is carried out on the waveform of the gap magnetic field to obtain the amplitude of each order of harmonic wave, and the formula is shown in the specification
Figure 384797DEST_PATH_IMAGE136
THD is calculated, the smaller the THD, the better the sinusoid. Compared with the traditional coreless motor structure, the invention reduces the THD from 28.6% to 18.2%, reduces the THD by 36.4%, and enables the air gap magnetic field waveform to be closer to a sine wave.
Example 2
Embodiment 2 discloses a sine wave rotor designed based on an outer rotor core eccentric structure, which is used in a hollow cup type sine wave flywheel motor. Referring to fig. 4 and 5, it includes an outer rotor core 1, a permanent magnet 2, a magnetism isolating block 6, a hollow cup stator 3, an inner rotor core 4, and a rotor shaft 5. The outer rotor iron core 1 and the inner rotor iron core 4 are both fixedly connected to the rotor shaft 5, so that the outer rotor iron core 1 and the inner rotor iron core 4 can rotate together with the rotor shaft 5. When the permanent magnet synchronous motor is arranged, the radial outer side of the outer rotor iron core 1 is arranged at the outer end of the rotor shaft 5, the radial inner side of the inner rotor iron core 4 is arranged at the inner end of the rotor shaft 5, a plurality of tile-shaped permanent magnets 2 are alternately arranged on the outer circular surface of the inner rotor iron core 4, the magnetizing directions of the two adjacent permanent magnets 2 are opposite, the thickness of the tile-shaped permanent magnets 2 is determined according to the actual working requirement of the motor, and the number of the tile-shaped permanent magnets is determined according to the number of pole pairs. The magnetic isolation blocks 6 are also tile-shaped and are arranged between two adjacent permanent magnets 2, and the number of the magnetic isolation blocks is the same as that of the permanent magnets.
The inner rotor core 4 is circular ring shaped. The outer rotor iron core 1 has a circular outline and an outline radius
Figure 191079DEST_PATH_IMAGE138
The inner contour of the outer rotor iron core 1 is determined by actual requirements of the motor, and is formed by a group of eccentric arcs protruding inwards, the number of the eccentric arcs is equal to that of the permanent magnets 2, and the positions of the eccentric arcs correspond to the permanent magnets 2 one by one. The number of the eccentric arcs on the outer rotor iron core 1 is
Figure 365709DEST_PATH_IMAGE140
And satisfies the relation:
Figure 232033DEST_PATH_IMAGE142
wherein
Figure 492113DEST_PATH_IMAGE144
The number of pole pairs of the motor is shown. An air gap of the motor is formed between the radial inner side of the outer rotor core 1 and the permanent magnet 2, the hollow cup stator 3 is arranged in the air gap and is fixed on the machine shell, and magnetic flux generated by the permanent magnet 2 forms a closed loop through the outer rotor core 1, the inner rotor core 4 and the air gap between the outer rotor core 1 and the inner rotor core 4.
When the motor is arranged, the circular outline of the outer rotor core 1, the inner outline of the permanent magnet 2 and the inner outline of the inner rotor core 4 are concentrically arranged, and the concentric point is used as the geometric center of the motor (also the geometric center of the rotor). Two end points of the eccentric arc are positioned on an extension line of a connecting line of the middle point of the tile-shaped edges of the magnetic separation blocks 6 at two sides of the corresponding permanent magnet 2 and the geometric center of the motor, the circle center of the eccentric arc is positioned on a reverse extension line of the connecting line of the middle point of the arc-shaped edge of the corresponding permanent magnet 2 and the geometric center of the motor, and the circle center of the eccentric arc is positioned on the radial outer side of the outer rotor iron core 1 outline, namely the connecting line of the middle point of the eccentric arc and the circle center of the eccentric arc passes through the radial outer outline of the outer rotor iron core 1.
As shown in fig. 5, point O is the geometric center of the motor; A. b, two points are two end points of the eccentric arc, O' point is the center of the eccentric arc, and H point is the middle point of the eccentric arc; C. d, E is the middle point of the tile-shaped edge of the magnetic isolation blocks at the two sides of the permanent magnet 2,
Figure 102086DEST_PATH_IMAGE146
is the thickness of the permanent magnet 2;
Figure 865643DEST_PATH_IMAGE148
the radius of the outer contour of the inner rotor iron core 4;
Figure 168448DEST_PATH_IMAGE150
is the radius of the eccentric arc;
Figure 650245DEST_PATH_IMAGE152
from the middle point of the eccentric arc to the geometric center of the motorThe distance of (a) to (b),
Figure 63909DEST_PATH_IMAGE154
the eccentric value is the distance between the center of the eccentric arc and the geometric center of the motor;
Figure 947551DEST_PATH_IMAGE156
the radius of the outer contour of the outer rotor iron core 1;
Figure 421258DEST_PATH_IMAGE158
is the inner diameter of the tile-shaped magnetic isolating block 6,
Figure 390351DEST_PATH_IMAGE160
the outer diameter of the tube is the same as the diameter of the tube,
Figure 76547DEST_PATH_IMAGE162
is its opening angle;
Figure 83205DEST_PATH_IMAGE164
is the tile-shaped opening angle of the permanent magnet 2.
The two end points A, B of the eccentric arc are on the extension line of the connecting line of the middle point C, D of the tile-shaped edge of the magnetic isolating block 6 at the two sides of the corresponding permanent magnet 2 and the geometric center O of the motor, namely A is on the extension line of the line segment OC and B is on the extension line of the line segment OD.
The center of the eccentric arc is on the extension line of the connecting line of the arc-shaped center point of the corresponding permanent magnet 2 and the geometric center of the motor, namely, the point O 'is positioned on the extension line of the line segment OH and positioned on the radial outer side of the outline of the outer rotor iron core 1, namely, the connecting line O' H of the arc-shaped center point and the center of the arc passes through the radial outline of the outer rotor iron core 1.
Meanwhile, the sine wave rotor designed based on the outer rotor core eccentric structure meets the following design regarding dimensions when being arranged:
1) the tile-shaped inner diameter of the magnetic isolation block is
Figure 727813DEST_PATH_IMAGE166
And satisfies the relation:
Figure 184202DEST_PATH_IMAGE168
the tile-shaped outer diameter is
Figure DEST_PATH_IMAGE170
And satisfies the relation:
Figure DEST_PATH_IMAGE172
wherein
Figure DEST_PATH_IMAGE174
Is the radius of the outer contour of the inner rotor iron core,
Figure DEST_PATH_IMAGE176
is the thickness of the permanent magnet 2;
2) the tile-shaped opening angle of the magnetic isolation block is
Figure DEST_PATH_IMAGE178
And satisfies the relation:
Figure DEST_PATH_IMAGE180
tile-shaped opening angle of permanent magnet 2
Figure DEST_PATH_IMAGE182
Satisfy the relation
Figure DEST_PATH_IMAGE184
Wherein
Figure DEST_PATH_IMAGE186
The number of pole pairs of the motor is;
3) the number of eccentric arcs on the outer rotor iron core is
Figure DEST_PATH_IMAGE188
And satisfies the relation:
Figure DEST_PATH_IMAGE190
；
4) the distance from the middle point of the eccentric arc to the geometric center of the motor is
Figure DEST_PATH_IMAGE192
And satisfies the relation:
Figure DEST_PATH_IMAGE194
in the formula
Figure DEST_PATH_IMAGE196
Is the radius of the outer contour of the inner rotor iron core,
Figure DEST_PATH_IMAGE198
is the thickness of the permanent magnet;
5) the radius of the eccentric arc is
Figure DEST_PATH_IMAGE200
And satisfies the relation:
Figure DEST_PATH_IMAGE202
wherein
Figure DEST_PATH_IMAGE204
The coefficient of the magnetic isolation block satisfies the relation:
Figure DEST_PATH_IMAGE206
；
6) the distance between the center of the eccentric arc and the geometric center of the motor is an eccentric value
Figure DEST_PATH_IMAGE208
And satisfies the relation:
Figure DEST_PATH_IMAGE210
。
7) the radius of the circular outline of the outer rotor iron core is
Figure DEST_PATH_IMAGE212
And satisfies the relation:
Figure DEST_PATH_IMAGE214
。
this embodiment 2 uses an inner rotor core outer diameter
Figure DEST_PATH_IMAGE216
Is 45mm, and the thickness of the permanent magnet
Figure DEST_PATH_IMAGE218
6mm, number of pole pairs
Figure DEST_PATH_IMAGE220
For example, the hollow cup type sine wave motor designed based on the eccentric structure of the outer rotor core is 6, and the magnetic isolation block and the outer rotor core are designed:
is composed of
Figure DEST_PATH_IMAGE222
Obtaining the tile-shaped inner diameter of the magnetic separation block
Figure DEST_PATH_IMAGE224
Is of the formula
Figure DEST_PATH_IMAGE226
Obtaining the tile-shaped outer diameter of the magnetic separation block
Figure DEST_PATH_IMAGE228
；
Is composed of
Figure DEST_PATH_IMAGE230
Dewar tile type opening angle
Figure DEST_PATH_IMAGE232
Satisfy the requirement of
Figure DEST_PATH_IMAGE234
In order to facilitate the processing and the manufacturing,
Figure DEST_PATH_IMAGE236
preferably takes on a value of
Figure DEST_PATH_IMAGE238
Is of the formula
Figure DEST_PATH_IMAGE240
Determining the tile-shaped opening angle of the permanent magnet 2
Figure DEST_PATH_IMAGE242
Is composed of
Figure DEST_PATH_IMAGE244
(28.5°)；
Is composed of
Figure DEST_PATH_IMAGE246
Calculating the distance from the midpoint of the single eccentric arc to the geometric center of the motor
Figure DEST_PATH_IMAGE248
Satisfy the requirement of
Figure DEST_PATH_IMAGE250
In order to facilitate the processing,
Figure DEST_PATH_IMAGE252
preferably 58 mm;
is composed of
Figure DEST_PATH_IMAGE254
Determining the radius of a single eccentric arc
Figure DEST_PATH_IMAGE256
Satisfy the requirement of
Figure DEST_PATH_IMAGE258
In order to facilitate the processing,
Figure DEST_PATH_IMAGE260
preferably 25 mm;
is composed of
Figure DEST_PATH_IMAGE262
Calculating an eccentricity value
Figure DEST_PATH_IMAGE264
83mm, by formula
Figure DEST_PATH_IMAGE266
Determining the radius of the circular outer side of the outer rotor core
Figure DEST_PATH_IMAGE268
Satisfy the requirement of
Figure DEST_PATH_IMAGE270
In order to facilitate the processing,
Figure DEST_PATH_IMAGE272
preferably 95 mm.
The motor parameters of the traditional hollow cup type motor are that the outer diameter of an eccentric outer rotor is 95mm, the inner diameter is 58mm, and the number of pole pairs is
Figure DEST_PATH_IMAGE274
6 pairs, the outer diameter of the inner rotor is 45mm, the outer diameter of the permanent magnet is 51mm, the thickness is 6mm, and the inner diameter is 45 mm. Compared with the traditional hollow cup type motor, the air gap field of the hollow cup type sine wave motor with the magnetic isolating blocks designed based on the outer rotor core structure is closer to a sine wave. Referring to the attached figure 6, the sine of the air-gap magnetic field waveform is evaluated by introducing a Total Harmonic Distortion (THD), the air-gap magnetic field waveform is subjected to Fourier decomposition transformation to obtain the amplitude of each order of harmonic, and the formula is shown
Figure DEST_PATH_IMAGE276
THD is calculated, the smaller the THD, the better the sinusoid. Compared with the traditional coreless motor structure, the invention reduces THD from 29.7% to 16.4%, reduces THD by 41.4%, and makes the air gap magnetic field waveform closer to sine wave.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A sine wave rotor designed based on an eccentric structure of an outer rotor iron core comprises the outer rotor iron core, a permanent magnet, a stator, an inner rotor iron core and a rotor shaft, the radial outer side of the outer rotor iron core is arranged at the outer end of the rotor shaft, the radial inner side of the inner rotor iron core is arranged at the inner end of the rotor shaft, it is characterized in that a plurality of tile-shaped permanent magnets are alternately arranged along the radial outer side of the inner rotor iron core, the magnetizing directions of two adjacent permanent magnets are opposite, the outer contour of the outer rotor iron core is circular, the inner contour of the outer rotor iron core is formed by a plurality of circumferential eccentric arcs protruding inwards, the number of the eccentric arcs is the same as that of the permanent magnets, the positions of the eccentric arcs correspond to the permanent magnets one by one, an annular air gap is formed between the radial inner side of the outer rotor iron core and the permanent magnets, and the stator is arranged in the annular air gap and fixed on the machine shell;
the circular outline of the outer rotor iron core, the inner outline and the outer outline of the permanent magnet and the inner outline and the outer outline of the inner rotor iron core are arranged concentrically, the concentric point is the geometric center of the rotor, two end points of the eccentric arc are positioned on the extension line of the connecting line of the two side edges of the corresponding permanent magnet and the geometric center of the rotor, the circle center of the eccentric arc is positioned on the reverse extension line of the connecting line of the middle point of the corresponding permanent magnet and the geometric center of the rotor, and the circle center of the eccentric arc is positioned on the radial outer side of the outer rotor iron core.
2. The sine wave rotor designed based on the outer rotor core eccentric structure according to claim 1, wherein the distance from the midpoint of the eccentric arc to the geometric center of the rotor is
Figure 666195DEST_PATH_IMAGE001
And satisfies the relation:
Figure 114494DEST_PATH_IMAGE002
wherein
Figure 300756DEST_PATH_IMAGE003
Is the radius of the outer contour of the inner rotor iron core,
Figure 430386DEST_PATH_IMAGE004
is the thickness of the permanent magnet.
3. The sine wave rotor designed based on the outer rotor core eccentric structure according to claim 2, wherein the radius of the eccentric arc is such that the relation:
Figure 775917DEST_PATH_IMAGE005
wherein
Figure 4904DEST_PATH_IMAGE006
Is the number of pole pairs.
4. The sine wave rotor designed based on the eccentric structure of the outer rotor core as recited in claim 2, further comprising tile-shaped magnetic barriers with the same number as the permanent magnets, wherein the magnetic barriers are disposed between two adjacent permanent magnets, and two end points of the eccentric arc are located on an extension line connecting the center of the tile-shaped edges of the magnetic barriers at two sides of the corresponding permanent magnet and the geometric center of the rotor.
5. The sine wave rotor designed based on the eccentric structure of the outer rotor core as claimed in claim 4, wherein the inner diameter of the tile shape of the magnetic isolation block is
Figure 803095DEST_PATH_IMAGE007
And satisfies the relation:
Figure 674099DEST_PATH_IMAGE008
(ii) a The tile-shaped outer diameter of the magnetic isolation block is
Figure 874137DEST_PATH_IMAGE009
And satisfies the relation:
Figure 274025DEST_PATH_IMAGE010
(ii) a Wherein
Figure 762775DEST_PATH_IMAGE011
Is the radius of the outer contour of the inner rotor iron core,
Figure 30946DEST_PATH_IMAGE012
is the thickness of the permanent magnet.
6. The sine wave rotor designed based on the eccentric structure of the outer rotor core as recited in claim 5, wherein the tile-shaped opening angle of the magnetic isolation block is
Figure 957926DEST_PATH_IMAGE013
And satisfies the relation:
Figure 184508DEST_PATH_IMAGE014
the tile-shaped opening angle of the permanent magnet
Figure DEST_PATH_IMAGE015
Satisfy the relation
Figure 567079DEST_PATH_IMAGE016
Wherein
Figure DEST_PATH_IMAGE017
The number of pole pairs of the motor is shown.
7. The sine wave rotor designed based on the outer rotor core eccentric structure according to claim 6, wherein the radius of the eccentric arc is
Figure 45465DEST_PATH_IMAGE018
And satisfies the relation:
Figure DEST_PATH_IMAGE019
wherein
Figure 626619DEST_PATH_IMAGE020
The coefficient of the magnetic isolation block satisfies the relation:
Figure DEST_PATH_IMAGE021
。
8. according to claim3 or 7, the sine wave rotor designed based on the eccentric structure of the outer rotor core is characterized in that the distance between the center of the eccentric arc and the geometric center of the rotor is an eccentric value
Figure 227364DEST_PATH_IMAGE022
And satisfies the relation:
Figure DEST_PATH_IMAGE023
。
9. the sine wave rotor designed based on the eccentric structure of the outer rotor core as claimed in claim 8, wherein the radius of the circular contour of the outer rotor core is set to be
Figure 159548DEST_PATH_IMAGE024
And satisfies the relation:
Figure DEST_PATH_IMAGE025
。
10. the sine wave rotor designed based on the eccentric structure of the outer rotor core according to claim 1 or 4, wherein the number of the eccentric arcs on the outer rotor core is as follows, and satisfies the relation:
Figure 379308DEST_PATH_IMAGE026
wherein
Figure DEST_PATH_IMAGE027
Is the number of pole pairs.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0392028A1 (en) * 1988-10-17 1990-10-17 Fanuc Ltd. Permanent-magnet synchronous motor
JP2007028848A (en) * 2005-07-20 2007-02-01 Yaskawa Electric Corp Permanent magnet electric motor
US7245054B1 (en) * 2000-11-01 2007-07-17 Emerson Electric Co. Permanent magnet electric machine having reduced cogging torque
EP3451498A1 (en) * 2017-08-30 2019-03-06 Lakeview Innovation Ltd. Multipolar rotor with loaf-shaped permanent magnets
KR20190083812A (en) * 2018-01-05 2019-07-15 엠토 주식회사 A Ring Magnet Applied Type of a Rotor of a Motor for a Robot with a Eccentric Type of a Structure Having a Lower Cogging and a Lower Torque Ripple
CN209120022U (en) * 2018-11-14 2019-07-16 哈尔滨理工大学 A kind of Novel dual-rotor permanent magnet motor structure
CN112865459A (en) * 2021-04-12 2021-05-28 北京航空航天大学 Hollow cup structure motor with arc permanent magnet

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0392028A1 (en) * 1988-10-17 1990-10-17 Fanuc Ltd. Permanent-magnet synchronous motor
US7245054B1 (en) * 2000-11-01 2007-07-17 Emerson Electric Co. Permanent magnet electric machine having reduced cogging torque
JP2007028848A (en) * 2005-07-20 2007-02-01 Yaskawa Electric Corp Permanent magnet electric motor
EP3451498A1 (en) * 2017-08-30 2019-03-06 Lakeview Innovation Ltd. Multipolar rotor with loaf-shaped permanent magnets
KR20190083812A (en) * 2018-01-05 2019-07-15 엠토 주식회사 A Ring Magnet Applied Type of a Rotor of a Motor for a Robot with a Eccentric Type of a Structure Having a Lower Cogging and a Lower Torque Ripple
CN209120022U (en) * 2018-11-14 2019-07-16 哈尔滨理工大学 A kind of Novel dual-rotor permanent magnet motor structure
CN112865459A (en) * 2021-04-12 2021-05-28 北京航空航天大学 Hollow cup structure motor with arc permanent magnet

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