CN211296356U

CN211296356U - Motor rotor, reluctance motor and electric automobile

Info

Publication number: CN211296356U
Application number: CN201922204215.6U
Authority: CN
Inventors: 胡余生; 陈彬; 童童; 黎永材; 王勇; 方磊
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2019-12-09
Filing date: 2019-12-09
Publication date: 2020-08-18
Anticipated expiration: 2029-12-09

Abstract

The application provides a motor rotor, reluctance motor and electric automobile. This electric motor rotor includes rotor core (1), be provided with a plurality of magnetic barrier groups along circumference on rotor core (1), every magnetic barrier group is including two at least magnetic flux barriers (2) along radial setting, form magnetic conduction passageway (3) between adjacent magnetic flux barrier (2), in the cross-section of the central axis of perpendicular to rotor core (1), magnetic flux barrier (2) that lie in the radial outside under the same pole form the recess, there is mounting groove (4) of a style of calligraphy on the rotor core in the recess, mounting groove (4) are including first slot part (5) that lie in first end and second slot part (6) that lie in the second end, first slot part (5) and second slot part (6) communicate with each other, the radial thickness of first slot part (5) and second slot part (6) is different. According to the motor rotor, the air gap flux density waveform which is basically sinusoidal and symmetrically distributed can be obtained under the load condition, and the torque pulsation and the iron loss of the motor are reduced.

Description

Motor rotor, reluctance motor and electric automobile

Technical Field

The application relates to the technical field of motor equipment, in particular to a motor rotor, a reluctance motor and an electric automobile.

Background

The industrial motor is widely applied to the fields of fans, water pumps, general machinery and the like. Currently, an IE2 asynchronous motor is mainly used, and the efficiency is low, the volume is large and the process is complex; in some high-energy-efficiency occasions, the energy efficiency of IE4 or above can be achieved by adopting a permanent magnet synchronous motor (IPM), but the rare earth permanent magnet motor needs to use a large amount of rare earth permanent magnet materials, and the popularization is slow due to overhigh cost.

The permanent magnet motor has armature reaction in the working process, the distribution of the permanent magnets is symmetrical along the central line of a magnetic pole under the condition of no load, so that the magnetic density distribution is symmetrical, and under the condition of interaction of the no-load magnetic steel and a magnetic field at the side of a stator under the armature reaction, the magnetic density distribution of the permanent magnets becomes nonuniform, and the conditions of partial magnetization and partial demagnetization are generated. The magnetic density distribution under the load condition is often used for determining the noise and torque ripple level of the motor, so the problem of air gap magnetic density distortion caused by armature reaction influences the sine of an air gap magnetic density waveform and increases the torque ripple and iron loss of the motor.

SUMMERY OF THE UTILITY MODEL

Therefore, an object of the present invention is to provide a motor rotor, a reluctance motor and an electric vehicle, which can obtain a substantially sinusoidal and symmetrically distributed air gap flux density waveform under a load condition, and reduce motor torque ripple and iron loss.

In order to solve the problem, the application provides a motor rotor, including rotor core, be provided with a plurality of magnetic barrier groups along circumference on the rotor core, every magnetic barrier group is including two at least magnetic flux barriers along radial setting, form the magnetic conduction passageway between the adjacent magnetic flux barrier, in the cross-section of the central axis of perpendicular to rotor core, the magnetic flux barrier that lies in radial outside under the same pole forms the recess, there is the mounting groove of a style of calligraphy on the rotor core in the recess, the mounting groove is including the first slot part that lies in first end and the second slot part that lies in the second end, first slot part and second slot part communicate with each other, the radial thickness of first slot part and second slot part is different.

Preferably, the first groove portion and the second groove portion are different in length.

Preferably, the thickness of the first groove portion is greater than the thickness of the second groove portion.

Preferably, the length of the first groove portion is greater than the length of the second groove portion.

Preferably, a first permanent magnet is arranged in the first slot part, a second permanent magnet is arranged in the second slot part, and the coercive force of the first permanent magnet is larger than that of the second permanent magnet.

Preferably, the first permanent magnet is a rare earth permanent magnet and the second permanent magnet is a ferrite permanent magnet.

Preferably, the thickness of the first permanent magnet is W1, the thickness of the second permanent magnet is W2, wherein W1/W2 is 1.5-2.0; and/or the length of the first permanent magnet is L1, the length of the second permanent magnet is L2, wherein L1/L2 is 1.2-1.8.

Preferably, the occupancy rate of the magnetic conduction channel is more than or equal to 0.32 and less than or equal to 0.38 or more than or equal to 0.54 and less than or equal to 0.63.

Preferably, the magnetic conductive path occupancy is determined by the following formula:

＝1-(w1+w3+w5)/(w1+w2+w3+w4+w5+2w6)

w1 is the thickness of the magnetic flux barrier at the radial outermost side, w2 is the thickness of the magnetic conduction channel adjacent to the magnetic flux barrier at the radial outermost side, and so on, w6 is the thickness of the iron core between the circumferential outer side wall of the magnetic flux barrier at the radial innermost side under the same pole and the circumferential outer side wall of the pole.

Preferably, the pole arc coefficient of the permanent magnet in the mounting groove is A0, wherein A0 is more than or equal to 0.35 and less than or equal to 0.46; and/or the pole arc coefficient of the permanent magnet in the mounting groove is A0, the pole arc coefficient of the magnetic conduction channel adjacent to the magnetic flux barrier at the outermost side in the radial direction is A1, and the pole arc coefficient of the adjacent magnetic conduction channel positioned at the outer side in the circumferential direction of the magnetic conduction channel is A2, wherein A2-A1 is more than A1-A0.

According to another aspect of the present application, a reluctance motor is provided, which includes a motor rotor and a motor stator, wherein the motor rotor is the motor rotor described above.

According to another aspect of the application, an electric vehicle is provided, which comprises the motor rotor or the reluctance motor.

The application provides an electric motor rotor, including rotor core, be provided with a plurality of magnetic barrier groups along circumference on the rotor core, every magnetic barrier group is including two at least magnetic flux barriers along radial setting, form the magnetic conduction passageway between the adjacent magnetic flux barrier, in the cross-section of the central axis of perpendicular to rotor core, the magnetic flux barrier that lies in radial outside under the same pole forms the recess, there is the mounting groove of a style of calligraphy on the rotor core in the recess, the mounting groove is including the first slot part that lies in first end and the second slot part that lies in the second end, first slot part and second slot part communicate with each other, the radial thickness of first slot part and second slot part is different. Through carrying out the split with a style of calligraphy mounting groove for a style of calligraphy mounting groove forms the first slot part and the second slot part that radial thickness is different, can set up the permanent magnet that the thickness is different respectively in first slot part and second slot part, thereby can utilize the permanent magnet of different thickness to form different anti demagnetization abilities, can form combination formula permanent magnet structure, obtains the air gap magnetic density wave form of basic sine and symmetric distribution under the load condition, reduces motor torque pulsation and iron loss.

Drawings

Fig. 1 is a schematic structural diagram of a rotor of an electric machine according to an embodiment of the present application;

FIG. 2 is a first dimensional block diagram of a rotor of an electric machine according to an embodiment of the present application;

FIG. 3 is a second dimensional block diagram of a rotor of an electric machine according to an embodiment of the present application;

fig. 4 is a schematic view of magnetic lines of force when the ID of the rotor of the motor of the embodiment of the present application is 0;

FIG. 5 is a schematic view of magnetic lines of force of a rotor of a motor of an embodiment of the present application at ID < 0;

FIG. 6 is a schematic illustration of the field increasing and field reducing of the rotor of the electric machine according to the embodiment of the present application;

FIG. 7 is a graph of the relationship between the output force of the motor rotor and the occupancy rate of the magnetic conduction channel according to the embodiment of the present application;

FIG. 8 is a graph of torque ripple factor versus A0 for a motor rotor according to an embodiment of the present disclosure;

fig. 9 is a graph comparing the flux density curves of the rotor of the motor of the embodiment of the present application and the load gap of the prior art.

The reference numerals are represented as:

1. a rotor core; 2. a magnetic flux barrier; 3. a magnetic conduction channel; 4. mounting grooves; 5. a first groove portion; 6. a second groove portion; 7. a first permanent magnet; 8. a second permanent magnet.

Detailed Description

With combined reference to fig. 1 to 9, according to an embodiment of the present application, a motor rotor includes a rotor core 1, a plurality of magnetic barrier groups are circumferentially disposed on the rotor core 1, each magnetic barrier group includes at least two magnetic flux barriers 2 radially disposed, a magnetic conduction channel 3 is formed between adjacent magnetic flux barriers 2, in a cross section perpendicular to a central axis of the rotor core 1, a magnetic flux barrier 2 located at a radially outermost side under a same pole forms a groove, a mounting groove 4 in a shape of a straight line is disposed on the rotor core 1 in the groove, the mounting groove 4 includes a first groove portion 5 located at a first end and a second groove portion 6 located at a second end, the first groove portion 5 and the second groove portion 6 are communicated, and radial thicknesses of the first groove portion 5 and the second groove portion 6 are different.

The utility model provides a motor rotor is through carrying out the split with a style of calligraphy mounting groove 4 for a style of calligraphy mounting groove 4 forms the first slot part 5 and the second slot part 6 that radial thickness is different, can set up the permanent magnet of different thickness in first slot part 5 and second slot part 6 respectively, thereby can utilize the permanent magnet of different thickness to form different anti demagnetization abilities, can form combination formula permanent magnet structure, obtain the air gap magnetic density wave form of basic sine and symmetric distribution under the load condition, reduce motor torque pulsation and iron loss.

The mounting groove 4 is bisected by the pole center line in the length direction, so that the permanent magnets on both sides of the pole center line can have the same length.

The flux barriers 2 are formed of air slots, and the shape of the flux barriers 2 may be U-shaped, inverted trapezoidal, or other shapes.

Preferably, the lengths of the first slot part 5 and the second slot part 6 are different, and the lengths of the permanent magnets with different thicknesses can be reasonably distributed, so that the permanent magnets with different thicknesses can select proper matching lengths, and a substantially sinusoidal and symmetrically distributed air gap flux density waveform under a load condition can be more conveniently obtained.

In the present embodiment, the thickness of the first groove portion 5 is larger than the thickness of the second groove portion 6.

The length of the first groove portion 5 is greater than the length of the second groove portion 6.

Preferably, a first permanent magnet 7 is arranged in the first slot portion 5, a second permanent magnet 8 is arranged in the second slot portion 6, and the coercive force of the first permanent magnet 7 is larger than that of the second permanent magnet 8.

The thickness of the first permanent magnet 7 is W1, the thickness of the second permanent magnet 8 is W2, wherein W1/W2 is 1.5-2.0.

The length of the first permanent magnet 7 is L1, the length of the second permanent magnet 8 is L2, wherein L1/L2 is 1.2-1.8.

As can be seen from fig. 4, under the ID ═ 0 control, when the reluctance torque is not generated, the magnetic lines of force of the armature reaction thereof and the permanent magnet magnetic field interact with each other, so that half of the permanent magnets of each pole are magnetized and half are demagnetized. Wherein the front pole is magnetized and the rear pole is demagnetized (default counterclockwise is the rotation direction, wherein the front part of each pole rotation direction is the front pole and the other part is the rear pole). The permanent magnet auxiliary reluctance motor needs to be subjected to field weakening control to enable the composite torque to be maximum, so that the armature magnetic field needs to be further advanced by an angle relative to the rotor on the basis that the ID is 0. As shown in fig. 5, at this time, the area of the permanent magnet at the portion where demagnetization is performed is larger, more than half. At the moment, the magnetic field of the armature reaction is changed from the original symmetrical distribution to the asymmetrical distribution, and the sinusoidal distribution of the counter electromotive force of the motor is influenced.

In order to solve the problem, the embodiment of the application designs that L1 is larger than L2, the ratio range of the L1 and the ratio range of the L2 is in the range of 1.2-1.8, and the first permanent magnet 7 can be effectively utilized to offset the demagnetization effect of the stator magnetic field on the permanent magnet. When L1 is too small, the weak magnetic angle is increased, which is not enough to completely counteract the effect of the weak magnetic field, and when L1 is too large, the proportion of ferrite is too high, so that the permanent magnet characteristic of the whole motor is reduced, and the output of the motor is influenced.

Because the coercive force of the second permanent magnet 8 is low, the W1 is designed to be more than W2, the ratio of W1 to W2 is in the range of 1.5-2.0, and the ferrite cannot be too thick under the condition of ensuring sufficient demagnetization resistance, so that the weak magnetism is difficult to weaken. A further preferable range of W1/W2 is 1.8 to 2.0, and the demagnetized parts of the permanent magnets in each pole are shown in FIG. 6. In fig. 6, the center line is a magnetization/demagnetization boundary line when ID is 0, the arrow-headed portion is a demagnetization region when ID < 0, and the arrow-headed portion is a magnetization region when ID < 0.

In the present embodiment, the first permanent magnet 7 is a rare earth permanent magnet, and the second permanent magnet 8 is a ferrite permanent magnet. The motor rotor of the application is used through the collocation of rare earth permanent magnet and ferrite permanent magnet, compares traditional only to use ferrite permanent magnet motor to have higher power factor. When the first permanent magnet 7 is a rare earth permanent magnet, the main function is to provide a permanent magnetic field and to promote a no-load flux linkage. When the field weakening is performed, the ferrite permanent magnet mainly acts with the armature, and the field weakening current is smaller and the speed is easier to expand due to the fact that the ferrite is easier to be weakened because of poor magnetic characteristics. At the moment, the rare earth permanent magnet still keeps high permanent magnet flux output. Based on this, the power factor of the motor is increased, and in this embodiment, compared with the conventional structure, the power factor of the motor is increased from 0.85 to 0.88, the input current of the motor is reduced, and the system efficiency is improved.

In the embodiment, the occupancy rate of the magnetic conduction channel is more than or equal to 0.32 and less than or equal to 0.38 or more than or equal to 0.54 and less than or equal to 0.63.

The magnetic conduction channel occupancy can be determined by the following formula:

＝1-(w1+w3+w5)/(w1+w2+w3+w4+w5+2w6)

where w1 is the thickness of the radially outermost flux barrier 2, w2 is the thickness of the magnetic conduction channel 3 adjacent to the radially outermost flux barrier 2, and so on, and w6 is the thickness of the core between the circumferential outer side wall of the radially innermost flux barrier 2 and the circumferential outer side wall of the same pole, as shown in fig. 6.

When the occupancy of the magnetic conduction channel is within the range of 0.32-0.38, the torque output is larger. Because the magnetic flux barrier 2 is large, the magnetic leakage of the motor is small, the Q-axis inductance is low, and large torque output is obtained at the moment. When the occupancy of the magnetic conduction channel is in the range of 0.54-0.63, although the magnetic flux barrier 2 is smaller, the width of the D-axis magnetic conduction channel is larger, the inductance is larger, and a larger torque output is obtained at this time, as shown in fig. 7.

The pole arc coefficient of the permanent magnet in the mounting groove 4 is A0, wherein A0 is more than or equal to 0.35 and less than or equal to 0.46. When the permanent magnet pole arc coefficient is within this range, the motor torque ripple is low, as shown in fig. 8, and in this range, the peak-to-valley phase error can be realized when the permanent magnet torque and the reluctance torque are synthesized.

Preferably, the pole arc coefficient of the permanent magnet in the mounting groove 4 is a0, the pole arc coefficient of the magnetic conduction channel 3 adjacent to the outermost magnetic flux barrier 2 in the radial direction is a1, and the pole arc coefficient of the adjacent magnetic conduction channel 3 located at the circumferential outer side of the magnetic conduction channel 3 is a2, wherein a2-a1 > a1-a 0.

Through the design, the characteristic that the air gap magnetic field is still distributed basically in a sine symmetry mode under the armature reaction is realized, and the positive effects of inhibiting the motor torque pulsation and reducing the loss are achieved. As shown in fig. 9, which is a comparison graph of the air gap flux density waveforms under the load of the present application and the conventional scheme, it can be seen from the graph that after the scheme of the present application is adopted, the air gap flux density waveforms under the load are basically distributed in a sine and symmetrical mode, so that the torque ripple and the iron loss of the motor can be reduced.

According to an embodiment of the present application, a reluctance motor includes a motor rotor and a motor stator, and the motor rotor is the motor rotor described above.

According to an embodiment of the application, the electric vehicle comprises the motor rotor or the reluctance motor.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed. The foregoing is only a preferred embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present application, and these modifications and variations should also be considered as the protection scope of the present application.

Claims

1. The motor rotor is characterized by comprising a rotor core (1), wherein a plurality of magnetic barrier groups are arranged on the rotor core (1) along the circumferential direction, each magnetic barrier group comprises at least two magnetic flux barriers (2) arranged along the radial direction, a magnetic conduction channel (3) is formed between every two adjacent magnetic flux barriers (2), in a section perpendicular to the central axis of the rotor core (1), the flux barriers (2) below the same pole and at the outermost side in the radial direction form a groove, the rotor iron core (1) in the groove is provided with a linear mounting groove (4), the mounting groove (4) comprises a first groove part (5) at a first end and a second groove part (6) at a second end, the first groove part (5) and the second groove part (6) are communicated, and the radial thicknesses of the first groove part (5) and the second groove part (6) are different.

2. An electric machine rotor according to claim 1, characterized in that the lengths of the first slot part (5) and the second slot part (6) are different.

3. An electric machine rotor according to claim 1, characterised in that the thickness of the first slot part (5) is greater than the thickness of the second slot part (6).

4. An electric machine rotor according to claim 2, characterized in that the length of the first slot part (5) is greater than the length of the second slot part (6).

5. An electric machine rotor according to claim 3 or 4, characterized in that a first permanent magnet (7) is arranged in the first slot (5) and a second permanent magnet (8) is arranged in the second slot (6), the coercivity of the first permanent magnet (7) being larger than the coercivity of the second permanent magnet (8).

6. An electric machine rotor, according to claim 5, characterised in that said first permanent magnet (7) is a rare earth permanent magnet and said second permanent magnet (8) is a ferrite permanent magnet.

7. The electric machine rotor according to claim 6, characterized in that the first permanent magnet (7) has a thickness W1 and the second permanent magnet (8) has a thickness W2, wherein W1/W2 is 1.5-2.0; and/or the length of the first permanent magnet (7) is L1, the length of the second permanent magnet (8) is L2, and L1/L2 is 1.2-1.8.

8. The electric machine rotor of claim 1, wherein the magnetic conduction channel occupancy satisfies 0.32 ≦ 0.38 or 0.54 ≦ 0.63.

9. The electric machine rotor of claim 8, wherein the magnetic conduction path occupancy is determined by the formula:

＝1-(w1+w3+w5)/(w1+w2+w3+w4+w5+2w6)

w1 is the thickness of the magnetic flux barrier (2) at the radial outermost side, w2 is the thickness of the magnetic conduction channel (3) adjacent to the magnetic flux barrier (2) at the radial outermost side, and by analogy, w6 is the thickness of the iron core between the circumferential outer side wall of the magnetic flux barrier (2) at the radial innermost side under the same pole and the circumferential outer side wall of the pole.

10. The electric machine rotor as recited in claim 1, characterized in that the permanent magnet pole arc coefficient in the mounting groove (4) is A0, wherein 0.35 ≦ A0 ≦ 0.46; and/or the pole arc coefficient of the permanent magnet in the mounting groove (4) is A0, the pole arc coefficient of the magnetic conduction channel (3) adjacent to the magnetic flux barrier (2) at the outermost side in the radial direction is A1, and the pole arc coefficient of the magnetic conduction channel (3) adjacent to the outer side in the circumferential direction of the magnetic conduction channel (3) is A2, wherein A2-A1 is more than A1-A0.

11. A reluctance machine comprising a machine rotor and a machine stator, characterized in that the machine rotor is a machine rotor according to any of claims 1 to 10.

12. An electric vehicle comprising an electric machine rotor as claimed in any one of claims 1 to 10 or a reluctance machine as claimed in claim 11.