Built-in asymmetric rotor structure and permanent magnet motor

Abstract

The invention relates to the technical field of permanent magnet synchronous motors, and discloses a built-in asymmetric rotor structure and a permanent magnet motor, and the structure comprises a rotor core which is provided with a plurality of magnetic poles in the circumferential direction; the magnetic barrier assembly comprises a plurality of magnetic barrier structures, the plurality of magnetic barrier structures are respectively arranged on the plurality of magnetic poles, each magnetic barrier structure comprises a first magnetic barrier piece and a second magnetic barrier piece, the first magnetic barrier piece and the second magnetic barrier piece are connected through a magnetic bridge, and the first magnetic barrier piece and the second magnetic barrier piece are asymmetrically arranged; and the permanent magnet assembly comprises a plurality of first permanent magnets and a plurality of second permanent magnets, the first permanent magnets are arranged in the first magnetic barrier pieces, the second permanent magnets are arranged in the second magnetic barrier pieces, and the first permanent magnets and the second permanent magnets are made of different materials. By optimizing the combination of the rotor structure and the magnetic material, larger torque output and higher efficiency are achieved, torque pulsation is remarkably reduced, and the manufacturing cost is not remarkably increased in the process.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and particularly to an embedded asymmetric rotor structure and a permanent magnet motor. Background Art

[0002] Due to its high efficiency, high torque density, and excellent control performance, permanent magnet synchronous motors are widely used in fields such as electric vehicles, industrial robots, and numerical control machine tools. Traditional permanent magnet synchronous motors usually adopt a symmetric rotor structure to achieve high torque density by effectively utilizing the permanent magnet torque and reluctance torque. However, the traditional symmetric rotor design inherently has the problem of mismatch between the current angles corresponding to the peak values of the permanent magnet torque and the reluctance torque. This restricts the further improvement of the motor performance to a certain extent. With the continuous improvement of the requirements for motor performance in industrial equipment, developing new rotor structures and excitation methods has become the key to improving the overall performance of the motor.

[0003] In the patent "An Interpolar Asymmetric Rotor Structure and Motor" with the application number CN202211331139.5, a magnetic slot on the rotor core of an interpolar asymmetric rotor structure has different radii and arc angles, and permanent magnets of different sizes are used between adjacent poles, aiming to simplify the installation of permanent magnets and reduce torque fluctuations during motor operation, thereby reducing vibration and noise. However, this structure requires a combination of multiple punching sheets, which not only increases the cost but also brings difficulties in processing.

[0004] In the patent "Asymmetric Rotor Structure of Motor, Setting Method and Synchronous Reluctance Motor" with the application number CN201710446182.9 and the patent "Asymmetric Rotor Structure of Motor and Synchronous Reluctance Motor" with the application number CN201720687567.X, by setting magnetic conduction arms with different widths on the magnetic poles of the rotor to improve the problem of uneven magnetic density distribution, thereby increasing the torque output and efficiency of the motor under the same input current. However, the irregular arc-shaped magnetic barrier structure is difficult to locate, which greatly increases the processing difficulty.

[0005] Therefore, there is an urgent need for an embedded asymmetric rotor structure and a permanent magnet motor to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide an embedded asymmetric rotor structure and a permanent magnet motor to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above purpose, the present invention provides the following solution: The present invention provides an embedded asymmetric rotor structure, including:

[0008] A rotor core, on which a plurality of magnetic poles are circumferentially arranged;

[0009] Magnetic barrier assembly, comprising a plurality of magnetic barrier structures, wherein the plurality of magnetic barrier structures are respectively arranged on a plurality of magnetic poles, the magnetic barrier structure comprises a first magnetic barrier member and a second magnetic barrier member, the first magnetic barrier member and the second magnetic barrier member are connected by a magnetic bridge, and the first magnetic barrier member and the second magnetic barrier member are asymmetrically arranged;

[0010] Permanent magnet assembly, comprising a plurality of first permanent magnets and a plurality of second permanent magnets, the first permanent magnets are disposed within the first magnetic barrier member, the second permanent magnets are disposed within the second magnetic barrier member, and the materials of the first permanent magnets and the second permanent magnets are different.

[0011] According to an internal asymmetric rotor structure provided by the present invention, the first magnetic barrier member comprises a first magnetic barrier, a second magnetic barrier and a third magnetic barrier, the sizes of the first magnetic barrier, the second magnetic barrier and the third magnetic barrier are all different, and the first magnetic barrier, the second magnetic barrier and the third magnetic barrier are connected by a magnetic bridge.

[0012] According to an internal asymmetric rotor structure provided by the present invention, the first magnetic barrier has the largest size, the second magnetic barrier has the smallest size and is located between the first magnetic barrier and the third magnetic barrier.

[0013] According to an internal asymmetric rotor structure provided by the present invention, the second magnetic barrier member comprises a fourth magnetic barrier, and a plurality of the fourth magnetic barriers are arranged along the circumferential direction of the rotor core, and the fourth magnetic barrier is located between the first magnetic barrier and the second magnetic barrier.

[0014] According to an internal asymmetric rotor structure provided by the present invention, the fourth magnetic barrier is in a "one" - shaped structure.

[0015] According to an internal asymmetric rotor structure provided by the present invention, the first permanent magnets are two rare - earth permanent magnets, and the two rare - earth permanent magnets are respectively disposed within the first magnetic barrier and the second magnetic barrier.

[0016] According to an internal asymmetric rotor structure provided by the present invention, the second permanent magnets are ferrite permanent magnets, and the ferrite permanent magnets are disposed within the fourth magnetic barrier.

[0017] A permanent - magnet synchronous motor, comprising:

[0018] A stator;

[0019] An internal asymmetric rotor structure, wherein the rotor core is installed within the stator.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] An internal asymmetric rotor structure and a permanent magnet motor provided by the present invention optimize the magnetic flux distribution by arranging asymmetric first and second magnetic barriers on the rotor core, enabling the motor to output a larger torque under the same volume while improving the overall operating efficiency. By setting the first and second permanent magnets with different materials, the performance is improved without significantly increasing the manufacturing cost, which has good economic efficiency. This application realizes a larger torque output, higher efficiency, and significantly reduces torque ripple by optimizing the combination of the rotor structure and magnetic materials, and does not significantly increase the manufacturing cost in this process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings:

[0023] Figure 1 Schematic diagram of a quarter model of the asymmetric rotor of the present invention;

[0024] Figure 2 Schematic diagram of the stator winding structure of the present invention;

[0025] Figure 3 Expanded wiring diagram of the stator winding of the present invention;

[0026] Figure 4 Schematic diagram of the comparison of the output torque waveform of the present invention with the finite element simulation result of the torque curve of a symmetric motor;

[0027] Among them, 1, rotor core; 2, first magnetic barrier; 3, second magnetic barrier; 4, third magnetic barrier; 5, fourth magnetic barrier. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0029] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0030] Referring to Figures 1-4 , the present invention provides an internal asymmetric rotor structure, including:

[0031] The rotor core 1 is provided with a plurality of magnetic poles along the circumferential direction;

[0032] The magnetic barrier assembly includes a plurality of magnetic barrier structures, and the plurality of magnetic barrier structures are respectively arranged on the plurality of magnetic poles. The magnetic barrier structure includes a first magnetic barrier member and a second magnetic barrier member. The first magnetic barrier member and the second magnetic barrier member are connected by a magnetic bridge, and the first magnetic barrier member and the second magnetic barrier member are asymmetrically arranged;

[0033] The permanent magnet assembly includes a plurality of first permanent magnets and a plurality of second permanent magnets. The first permanent magnets are placed inside the first magnetic barrier member, and the second permanent magnets are placed inside the second magnetic barrier member. The materials of the first permanent magnets and the second permanent magnets are different.

[0034] In one embodiment of the present invention, the flux distribution is optimized by arranging the asymmetric first magnetic barrier member and second magnetic barrier member on the rotor core 1, enabling the motor to output a larger torque under the same volume, while improving the overall operating efficiency. By arranging the first permanent magnets and the second permanent magnets with different materials, the performance is improved without significantly increasing the manufacturing cost, having good economy.

[0035] As an alternative embodiment, the first magnetic barrier member includes a first magnetic barrier 2, a second magnetic barrier 3, and a third magnetic barrier 4. The sizes of the first magnetic barrier 2, the second magnetic barrier 3, and the third magnetic barrier 4 are all different, and the first magnetic barrier 2, the second magnetic barrier 3, and the third magnetic barrier 4 are connected by a magnetic bridge.

[0036] As an alternative embodiment, the first magnetic barrier 2 has the largest size, the second magnetic barrier 3 has the smallest size and is located between the first magnetic barrier 2 and the third magnetic barrier 4.

[0037] As an alternative embodiment, the second magnetic barrier member includes a fourth magnetic barrier 5. A plurality of fourth magnetic barriers 5 are arranged along the chordal direction of the rotor core 1, and the fourth magnetic barrier 5 is located between the first magnetic barrier 2 and the second magnetic barrier 3.

[0038] In one embodiment of the present invention, the asymmetric rotor structure optimizes the flux distribution, enabling the motor to output a larger torque under the same volume, while improving the overall operating efficiency.

[0039] As an alternative embodiment, the fourth magnetic barrier 5 is in a "one" - shaped structure.

[0040] In one embodiment of the present invention, the fourth magnetic barrier 5 is in a "one" - shaped structure and is positioned along the circumferential chord line direction.

[0041] As an alternative embodiment, the first permanent magnets are two rare - earth permanent magnets, and the two rare - earth permanent magnets are respectively arranged inside the first magnetic barrier 2 and the second magnetic barrier 3.

[0042] In one embodiment of the present invention, the rare earth permanent magnet is divided into two parts, which are respectively embedded in the first magnetic barrier 2 and the second magnetic barrier 3.

[0043] As an alternative embodiment, the second permanent magnet is a ferrite permanent magnet, and the ferrite permanent magnet is arranged in the fourth magnetic barrier 5.

[0044] In one embodiment of the present invention, the second permanent magnet is a ferrite permanent magnet, and the ferrite permanent magnet is embedded in the fourth magnetic barrier 5 to increase the torque density and suppress the torque ripple. The presence of the ferrite permanent magnet helps to stabilize the air-gap magnetic density when the load changes, reduce the torque fluctuation caused by the armature reaction, and improve the smoothness and reliability of the motor operation.

[0045] A permanent magnet synchronous motor, comprising:

[0046] A stator;

[0047] An embedded type asymmetric rotor structure, and the rotor core 1 is installed in the stator.

[0048] In one embodiment of the present invention, a 48-slot 4-pole high torque density permanent magnet synchronous motor with a positive pole is taken as an example to specifically introduce the present invention. This example adopts an integer-slot distributed winding, with 11 conductors per slot, a rotor outer diameter of 132 mm, a stator outer diameter of 80.22 mm, and an air-gap length of 0.82 mm. Compared with the 22.5° symmetry axis of the symmetric structure, the symmetry axis in this example is offset 7.3 mm from the original symmetry axis. The angle between the first permanent magnet in the first magnetic barrier 2 and the symmetry axis is 110°, and the angle between the first permanent magnet in the second magnetic barrier 3 and the symmetry axis is 27°. The material used is NdFeB rare earth permanent magnet of N36 grade. The fourth magnetic barrier 5 is symmetrically arranged along the original 22.5° axis, and the second permanent magnet in the magnetic barrier deviates 1 mm from the 22.5° axis, and the ferrite permanent magnet material of Y30BH grade is used. The distribution and magnetization direction of the permanent magnets refer to Figure 1 , where the total amount of rare earth permanent magnets is 104460 mm3, and the total amount of ferrite permanent magnets is 30900 mm3. The proposed invention realizes a larger average torque and a smaller torque ripple compared with the existing symmetric built-in permanent magnet synchronous motor scheme with single excitation. Figure 4 This is a comparison chart of the torque curves of this asymmetric hybrid excitation motor and the symmetric motor.

[0049] Principle of the present invention: First, the reason for asymmetrically setting the first permanent magnet is to pull in the permanent magnet torque curve and the reluctance torque curve, and the stator current lead angle position corresponding to the maximum value of the two curves, so as to make the permanent magnet torque and the reluctance torque reach the maximum value at the same current lead angle as much as possible, thereby increasing the torque density of the motor, improving the torque output and efficiency.

[0050] The reason for further setting a second permanent magnet with a remanence different from that of the first permanent magnet is that by adding the second permanent magnet in the direction of the rotor magnetic field axis, the sinusoidality of the rotor magnetic field is improved, thereby reducing the harmonic content of the air-gap magnetic field and reducing the torque ripple.

[0051] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0052] The embodiments described above are only for describing the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A built-in asymmetric rotor structure, characterized in that: include: A rotor core (1), wherein a plurality of magnetic poles are arranged on the rotor core (1) along a circumferential direction; A magnetic barrier assembly, comprising a plurality of magnetic barrier structures, wherein the plurality of magnetic barrier structures are respectively arranged on the plurality of magnetic poles, the magnetic barrier structure comprises a first magnetic barrier component and a second magnetic barrier component, the first magnetic barrier component and the second magnetic barrier component are connected via a magnetic bridge, and the first magnetic barrier component and the second magnetic barrier component are asymmetrically arranged; The permanent magnet assembly includes a plurality of first permanent magnets and a plurality of second permanent magnets. The first permanent magnets are placed in the first magnetic barrier, and the second permanent magnets are placed in the second magnetic barrier. The first permanent magnets and the second permanent magnets are made of different materials.

2. The built-in asymmetric rotor structure according to claim 1, characterized in that: The first magnetic barrier comprises a first magnetic barrier (2), a second magnetic barrier (3) and a third magnetic barrier (4); the sizes of the first magnetic barrier (2), the second magnetic barrier (3) and the third magnetic barrier (4) are different; the first magnetic barrier (2), the second magnetic barrier (3) and the third magnetic barrier (4) are connected by a magnetic bridge.

3. The built-in asymmetric rotor structure according to claim 2, characterized in that: The first magnetic barrier (2) has the largest size, and the second magnetic barrier (3) has the smallest size and is located between the first magnetic barrier (2) and the third magnetic barrier (4).

4. The built-in asymmetric rotor structure according to claim 3, characterized in that: The second magnetic barrier comprises a fourth magnetic barrier (5), a plurality of the fourth magnetic barriers (5) are arranged along the chord direction of the rotor core (1), and the fourth magnetic barrier (5) is located between the first magnetic barrier (2) and the second magnetic barrier (3).

5. The built-in asymmetric rotor structure according to claim 4, characterized in that: The fourth magnetic barrier (5) is an "I"-shaped structure.

6. The built-in asymmetric rotor structure according to claim 2, characterized in that: The first permanent magnets are two rare earth permanent magnets, and the two rare earth permanent magnets are respectively arranged in the first magnetic barrier (2) and the second magnetic barrier (3).

7. The built-in asymmetric rotor structure according to claim 4, characterized in that: The second permanent magnet is a ferrite permanent magnet, and the ferrite permanent magnet is arranged in the fourth magnetic barrier (5).

8. A permanent magnet synchronous motor, characterized in that: include: stator; A built-in asymmetric rotor structure as described in claim 1, wherein the rotor core (1) is installed inside the stator.

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