Rotor and synchronous reluctance motor comprising same

Abstract

The present invention discloses a rotor, having multiple flux barrier structures arranged in a circumferential direction of the rotor, each flux barrier structure comprising multiple layers of arc-shaped flux barriers which open toward an edge of the rotor, each of the multiple layers of arc-shaped flux barriers comprising at least three flux barrier segments, with a magnetic bridge provided between two adjacent flux barrier segments, wherein a flux barrier that is closest to the edge of the rotor is not filled with a magnetic substance, and a flux barrier adjacent to the flux barrier that is closest to the edge of the rotor is filled with a magnetic substance. In the present invention, each arc-shaped flux barrier layer comprises at least three flux barrier segments, the flux barriers that are closest to the edge of the rotor are not filled with a magnetic substance, and the flux barriers adjacent to the flux barriers that are closest to the edge of the rotor are filled with a magnetic substance; this not only enables the reluctance torque of the electric motor to be fully utilized so as to improve electric motor performance, but also allows the magnetic substance to be remote from the stator windings, so as to reduce the risk of the magnetic substance being demagnetized.

Description

[0001] Description

[0002] Rotor and synchronous reluctance motor comprising same

[0003] Technical Field

[0004] The present invention relates to the technical field of electric motors, in particular to a rotor and a synchronous reluctance motor comprising the rotor.

[0005] Background Art

[0006] As the development of new energy vehicles advances, drive motors are subject to ever higher performance requirements. For this reason, permanent magnet synchronous motors have become a mainstream choice. Fig. 1 shows a permanent magnet synchronous motor in the prior art. As shown in Fig. 1 , the permanent magnet synchronous motor comprises a stator and a rotor, with windings arranged on the stator, and magnetic material bodies (e.g. permanent magnets) arranged on the rotor. The magnetic material bodies are generally in the shape of cuboids. Correspondingly, flux barriers in the shape of cuboids are provided in the rotor. The magnetic material bodies are inserted in the flux barriers.

[0007] However, because the magnetic material bodies are in the shape of cuboids, the reluctance torque of the electric motor cannot be fully utilized, and a large number of permanent magnets are needed to provide permanent magnet torque. That is to say, to achieve the same output performance, the permanent magnet synchronous motor needs high-performance permanent magnets to make up for the deficiency in reluctance torque, so has a high cost. In addition, due to the high strength of the magnetic field close to the stator windings, the magnetic material bodies close to the rotor edge (i.e. closest to the stator windings) are at risk of being demagnetized.

[0008] Summary of the Invention

[0009] In view of the above, according to a first aspect of the present invention, a rotor is provided, the rotor having multiple flux barrier structures arranged in a circumferential direction of the rotor, each flux barrier structure comprising multiple layers of arc-shaped flux barriers which open toward an edge of the rotor, each of the multiple layers of arc-shaped flux barriers comprising at least three flux barrier segments, with a magnetic bridge provided between two adjacent flux barrier segments, wherein a flux barrier that is closest to the edge of the rotor is not filled with a magnetic substance, and a flux barrier adjacent to the flux barrier that is closest to the edge of the rotor is filled with a magnetic substance.

[0010] Optionally, each of the multiple layers of arc-shaped flux barriers comprises five flux barrier segments divided by four magnetic bridges, wherein two flux barrier segments that are closest to the edge of the rotor are not filled with a magnetic substance, two flux barrier segments adjacent to the two flux barrier segments that are closest to the edge of the rotor are filled with a magnetic substance, and a flux barrier segment that is furthest from the edge of the rotor is filled or not filled with a magnetic substance.

[0011] Optionally, the flux barrier that is closest to the edge of the rotor is filled with a non-magnetic substance.

[0012] Optionally, the non-magnetic substance comprises at least one of the following: air, plastic and glue.

[0013] Optionally, the magnetic substance is formed by mixing particles of a magnetic material and particles of a plastic, and the mass ratio of the particles of the magnetic material to the particles of the plastic can be adjusted.

[0014] Optionally, the magnetic material comprises at least one of the following: SmFeN, NdFeB and ferrite.

[0015] Optionally, the plastic comprises at least one of the following: PA12 (polylaurolactam), PP (polypropylene) and PPS (polyphenylene sulfide).

[0016] Optionally, a width and position of the magnetic bridge can be adjusted. Optionally, the number of the multiple layers of arc-shaped flux barriers comprises at least one of the following: 2, 3 and 4.

[0017] According to a second aspect of the present invention, a synchronous reluctance motor is provided, the synchronous reluctance motor comprising a stator, and the rotor according to the first aspect of the present invention, the stator being provided with a winding.

[0018] The rotor and the synchronous reluctance motor comprising said rotor according to the present invention can achieve at least one of the following advantages:

[0019] In the present invention, each arc-shaped flux barrier layer comprises at least three flux barrier segments, the flux barriers that are closest to the edge of the rotor are not filled with a magnetic substance, and the flux barriers adjacent to the flux barriers that are closest to the edge of the rotor are filled with a magnetic substance; this not only enables the reluctance torque of the electric motor to be fully utilized so as to improve electric motor performance, but also allows the magnetic substance to be remote from the stator windings, so as to reduce the risk of the magnetic substance being demagnetized.

[0020] In the present invention, four magnetic bridges may be preferably used to divide each arc-shaped flux barrier layer into five flux barrier segments, and the flux barrier segment that is furthest from the edge of the rotor may or may not be filled with a magnetic substance. In this way, the mechanical strength of the rotor can be increased with the aid of magnetic bridges; additionally, a decision can be made, based on the desired electric motor performance, as to whether it is necessary for the flux barrier segment furthest from the edge of the rotor to be filled with a magnetic substance.

[0021] In the present invention, the flux barriers that are closest to the edge of the rotor may be filled with non-magnetic substances of different types according to actual needs, so as to achieve the desired electric motor performance.

[0022] In the present invention, the mass ratio of the particles of magnetic material to the particles of plastic which form the magnetic substance can be adjusted, thereby making it possible to adjust the physical properties and magnetic properties of the magnetic substance according to actual needs.

[0023] In the present invention, lower-priced SmFeN and ferrite and higher-priced NdFeB may be used as the magnetic material depending on actual needs, so as to take both performance and cost of the electric motor into account.

[0024] In the present invention, the plastic may be chosen from PA12, PP and PPS, to adapt to different electric motor operating environments, e.g. electric motor operating temperatures.

[0025] In the present invention, the widths and positions of the magnetic bridges can be adjusted, thus enabling optimization of electric motor performance according to actual needs.

[0026] In the present invention, the number of multiple layers of arc-shaped flux barriers may be set (e.g. 2, 3 or 4 layers) according to actual needs, so as to obtain the desired electric motor performance.

[0027] Brief Description of the Drawings

[0028] Other details and advantages of the present invention will become obvious through the detailed description provided below. It should be understood that the drawings listed below are merely schematic and not drawn to scale, and thus should not be regarded as limiting the present application. The detailed description below makes reference to the drawings, wherein:

[0029] Fig. 1 shows a permanent magnet synchronous motor in the prior art.

[0030] Fig. 2 shows a rotor of a synchronous reluctance motor according to a particular embodiment of the present invention. Fig. 3 shows a portion of a synchronous reluctance motor according to a particular embodiment of the present invention.

[0031] Detailed Description of the Invention

[0032] Embodiments of the present invention are described below with reference to the drawings. Many specific details are expounded in the following description so that those skilled in the art can understand and realize the present invention more comprehensively. However, it is obvious to those skilled in the art that the invention can be realized without some of these specific details. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, consideration may be given to the use of any combination of the following features and key elements to implement the present invention, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages merely serve an explanatory purpose, and should not be regarded as key elements or definitions of the claims, unless explicitly stated in the claims.

[0033] Fig. 2 shows a rotor of a synchronous reluctance motor according to a particular embodiment of the present invention. Fig. 3 shows a portion of a synchronous reluctance motor according to a particular embodiment of the present invention.

[0034] As shown in Figs. 2 and 3, the rotor may be formed by stacking silicon steel sheets; and arc-shaped through-holes, i.e. flux barriers, are punched in the silicon steel sheets. The rotor has multiple flux barrier structures 1 arranged in the circumferential direction of the rotor, wherein each flux barrier structure comprises 4 layers of arc-shaped flux barriers 11 , 12, 13 and 14, which open toward an edge of the rotor. The 4 layers of arc-shaped flux barriers 11 , 12, 13 and 14 have the same axis of symmetry, e.g. the X-axis in Fig. 3. The X-axis preferably extends in a diametric direction of the rotor. Each of the 4 layers of arc-shaped flux barriers comprises 5 flux barrier segments; for example, the flux barrier layer 11 comprises 5 flux barrier segments 111 , 112, 113, 114 and 115. A magnetic bridge 15 is provided between two adjacent flux barrier segments. The two flux barrier segments 111 and 115 that are closest to the edge of the rotor are not filled with a magnetic substance. The two flux barrier segments 112 and 114 adjacent to the two flux barrier segments 111 and 115 that are closest to the edge of the rotor are filled with a magnetic substance (the black parts in the figure). Depending on actual needs (e.g. the dimensions and design performance of the electric motor), the flux barrier segment 113 that is furthest from the edge of the rotor may or may not be filled with a magnetic substance. Further, to obtain the desired electric motor performance, the two flux barrier segments 111 and 115 that are closest to the edge of the rotor may be filled with non-magnetic substances of different types according to actual needs, e.g. air, plastic or glue; these variants do not exceed the scope of protection of the present invention.

[0035] The specific number of flux barrier structures 1 arranged in the circumferential direction of the rotor may be set according to actual needs (e.g. the dimensions and design performance of the electric motor); for example, Fig. 2 shows 8 flux barrier structures 1 arranged in the circumferential direction of the rotor, but the number of flux barrier structures 1 could also be greater or less than 8. These variants do not exceed the scope of protection of the present invention.

[0036] The specific number of multiple layers of arc-shaped flux barriers in each flux barrier structure 1 may be set according to actual needs (e.g. the dimensions and design performance of the electric motor); for example, each flux barrier structure 1 shown in Figs. 2 and 3 comprises 4 layers of arc-shaped flux barriers 11 , 12, 13 and 14, but the number of layers of arc-shaped flux barriers could also be greater or less than 4, e.g. 2 or 3, and these variants do not exceed the scope of protection of the present invention. In addition, the specific shape of the arc-shaped flux barrier may be set according to actual needs (e.g. the dimensions and design performance of the electric motor), for example being a hyperbola; these variants do not exceed the scope of protection of the present invention. The multiple layers of arc-shaped flux barriers preferably have the same axis of symmetry, thus helping to improve electric motor performance, but the multiple layers of arc-shaped flux barriers could also not have the same axis of symmetry; these variants do not exceed the scope of protection of the present invention.

[0037] The specific number of multiple flux barrier segments in each arc-shaped flux barrier layer may be set according to actual needs (e.g. the dimensions and design performance of the electric motor); for example, Figs. 2 and 3 show each arc-shaped flux barrier layer as being divided into 5 flux barrier segments, but the number of multiple flux barrier segments could also be greater or less than 5, as long as the flux barriers that are closest to the edge of the rotor are not filled with a magnetic substance, and the flux barriers adjacent to the flux barriers that are closest to the edge of the rotor are filled with a magnetic substance. Preferably, the present invention employs the 5-segment flux barrier structure shown in Figs. 2 and 3, and the flux barrier segment that is furthest from the edge of the rotor may or may not be filled with a magnetic substance, depending on actual needs (e.g. the design performance of the electric motor). This allows the mechanical strength of the rotor to be increased with the aid of magnetic bridges; additionally, a decision can be made, based on the design performance of the electric motor, as to whether it is necessary for the flux barrier segment furthest from the edge of the rotor to be filled with a magnetic substance.

[0038] The position of the magnetic bridge 15 may be set according to actual needs (e.g. the dimensions and design performance of the electric motor), and these variants do not exceed the scope of protection of the present invention. Preferably, as shown in Fig. 3, to optimize electric motor performance, the magnetic bridges 15 may be distributed symmetrically at two sides of the axis of symmetry (the X-axis) of the multiple arc-shaped flux barriers.

[0039] The width of the magnetic bridge 15 may be set according to actual needs (e.g. the dimensions and design performance of the electric motor), and these variants do not exceed the scope of protection of the present invention. Preferably, to optimize electric motor performance, the width of the magnetic bridge can be adjusted.

[0040] The magnetic substance may be packed into the arc-shaped flux barriers in any suitable manner, and these variants do not exceed the scope of protection of the present invention. For example, the magnetic substance may be packed into the arc-shaped flux barriers by injection molding. The magnetic substance is anisotropic; after being injection molded into the flux barriers and cured, the magnetic substance must be magnetized. The magnetic substance may be formed by mixing particles of a magnetic material and particles of a plastic. The mass ratio of the particles of magnetic material to the particles of plastic can be adjusted to realize different physical properties and magnetic properties. Any suitable magnetic material, such as SmFeN, NdFeB and ferrite, may be used. Due to being lower-priced, SmFeN and ferrite can lower the cost of a synchronous reluctance motor. The proportions of the elements Sm, Fe and N in the magnetic material SmFeN can be adjusted (e.g. Srr^FeiyNs), to realize different physical properties and magnetic properties. Furthermore, any suitable plastic material may be used to adapt to different electric motor operating environments; for example, the plastic material may be PA12, PP and PPS.

[0041] Compared with the prior art, the rotor and the synchronous reluctance motor comprising said rotor in embodiments of the present invention have at least the following advantages:

[0042] In the present invention, each arc-shaped flux barrier layer comprises at least three flux barrier segments, the flux barriers that are closest to the edge of the rotor are not filled with a magnetic substance, and the flux barriers adjacent to the flux barriers that are closest to the edge of the rotor are filled with a magnetic substance; this not only enables the reluctance torque of the electric motor to be fully utilized so as to improve electric motor performance, but also allows the magnetic substance to be remote from the stator windings, so as to reduce the risk of the magnetic substance being demagnetized.

[0043] In the present invention, four magnetic bridges may be preferably used to divide each arc-shaped flux barrier layer into five flux barrier segments, and the flux barrier segment that is furthest from the edge of the rotor may or may not be filled with a magnetic substance. In this way, the mechanical strength of the rotor can be increased with the aid of magnetic bridges; additionally, a decision can be made, based on the desired electric motor performance, as to whether it is necessary for the flux barrier segment furthest from the edge of the rotor to be filled with a magnetic substance.

[0044] In the present invention, the flux barriers that are closest to the edge of the rotor may be filled with non-magnetic substances of different types according to actual needs, so as to achieve the desired electric motor performance.

[0045] In the present invention, the mass ratio of the particles of magnetic material to the particles of plastic which form the magnetic substance can be adjusted, thereby making it possible to adjust the physical properties and magnetic properties of the magnetic substance according to actual needs.

[0046] In the present invention, lower-priced SmFeN and ferrite and higher-priced NdFeB may be used as the magnetic material depending on actual needs, so as to take both performance and cost of the electric motor into account.

[0047] In the present invention, the plastic may be chosen from PA12, PP and PPS, to adapt to different electric motor operating environments, e.g. electric motor operating temperatures.

[0048] In the present invention, the widths and positions of the magnetic bridges can be adjusted, thus enabling optimization of electric motor performance according to actual needs.

[0049] In the present invention, the number of multiple layers of arc-shaped flux barriers may be set (e.g. 2, 3 or 4 layers) according to actual needs, so as to obtain the desired electric motor performance.

[0050] Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited to this. Any change or modification made by those skilled in the art without departing from the spirit and scope of the present invention should be included in the scope of protection thereof. Thus, the scope of protection of the present invention shall be the scope defined by the claims.

Claims

Claims1 . A rotor, wherein the rotor has multiple flux barrier structures arranged in a circumferential direction of the rotor, each flux barrier structure comprising multiple layers of arc-shaped flux barriers which open toward an edge of the rotor, each of the multiple layers of arc-shaped flux barriers comprising at least three flux barrier segments, with a magnetic bridge provided between two adjacent flux barrier segments, wherein a flux barrier that is closest to the edge of the rotor is not filled with a magnetic substance, and a flux barrier adjacent to the flux barrier that is closest to the edge of the rotor is filled with a magnetic substance.

2. The rotor as claimed in claim 1 , wherein each of the multiple layers of arc-shaped flux barriers comprises five flux barrier segments divided by four magnetic bridges, wherein two flux barrier segments that are closest to the edge of the rotor are not filled with a magnetic substance, two flux barrier segments adjacent to the two flux barrier segments that are closest to the edge of the rotor are filled with a magnetic substance, and a flux barrier segment that is furthest from the edge of the rotor is filled or not filled with a magnetic substance.

3. The rotor as claimed in claim 1 or 2, wherein the flux barrier that is closest to the edge of the rotor is filled with a non-magnetic substance.

4. The rotor as claimed in claim 3, wherein the non-magnetic substance comprises at least one of the following: air, plastic and glue.

5. The rotor as claimed in claim 1 or 2, wherein the magnetic substance is formed by mixing particles of a magnetic material and particles of a plastic, and the mass ratio of the particles of the magnetic material to the particles of the plastic can be adjusted.

6. The rotor as claimed in claim 5, wherein the magnetic material comprises at least one of the following: SmFeN, NdFeB and ferrite.

7. The rotor as claimed in claim 5, wherein the plastic comprises at least one of the following: PA12, PP and PPS.

8. The rotor as claimed in claim 1 or 2, wherein a width and position of the magnetic bridge can be adjusted.

9. The rotor as claimed in claim 1 or 2, wherein the number of the multiple layers of arc-shaped flux barriers comprises at least one of the following: 2, 3 and 4.

10. A synchronous reluctance motor, wherein the synchronous reluctance motor comprises a stator and the rotor as claimed in any one of claims 1 - 9, the stator being provided with a winding.

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