Rotor and synchronous reluctance motor comprising same

Abstract

The present invention discloses a rotor and a synchronous reluctance motor comprising the rotor. In the present invention, the rotor has an even number of flux barrier structures, each flux barrier structure comprising multiple arc-shaped flux barrier layers, the multiple arc-shaped flux barrier layers of each flux barrier structure having the same axis of symmetry, and each arc-shaped flux barrier layer comprising five flux barriers, wherein two outermost flux barriers are symmetric to each other with respect to the axis of symmetry, two middle flux barriers are symmetric to each other with respect to the axis of symmetry, and an innermost flux barrier is itself symmetric with respect to the axis of symmetry. Thus, the multi-layer flux barrier design with the same axis of symmetry can help to fully utilize the reluctance torque of the electric motor, so as to improve the output performance thereof. In addition, the two outermost flux barriers are not filled with a magnetic substance, so that the magnetic substance is remote from the stator windings to reduce the risk of the magnetic substance being demagnetized.

Description

[0001] Rotor and synchronous reluctance motor comprising same

[0002] Technical Field

[0003] The present invention relates to the technical field of electric motors, in particular to a rotor and a synchronous reluctance motor comprising the rotor.

[0004] Background Art

[0005] 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.

[0006] 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.

[0007] Summary of the Invention

[0008] In view of the above, according to a first aspect of the present invention, a rotor is provided, the rotor having an even number of flux barrier structures arranged in a circumferential direction of the rotor, each flux barrier structure comprising multiple arc-shaped flux barrier layers which open toward an edge of the rotor, the multiple arc-shaped flux barrier layers of each flux barrier structure having the same axis of symmetry, wherein each arc-shaped flux barrier layer comprises five flux barriers, with a magnetic bridge provided between two adjacent flux barriers, wherein the five flux barriers comprise an innermost flux barrier closest to the center of the rotor, two outermost flux barriers furthest from the center of the rotor, and two middle flux barriers located between the innermost flux barrier and the outermost flux barriers, wherein the two outermost flux barriers are symmetric to each other with respect to the axis of symmetry, the two middle flux barriers are symmetric to each other with respect to the axis of symmetry, and the innermost flux barrier is itself symmetric with respect to the axis of symmetry, wherein the two outermost flux barriers are not filled with a magnetic substance, the two middle flux barriers are filled with a magnetic substance, and the innermost flux barrier is filled or not filled with a magnetic substance.

[0009] Optionally, an angle between the axis of symmetry and a straight line passing through the center of a magnetic bridge between the outermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°, and an angle between the axis of symmetry and a straight line passing through the center of a magnetic bridge between the innermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°.

[0010] Optionally, a cross section of the outermost flux barrier comprises an innermost edge closest to the center of the rotor, an outermost edge furthest from the center of the rotor, and a first extension edge and a second extension edge extending between end points of the innermost edge and the outermost edge, the first extension edge being remote from the axis of symmetry and the second extension edge being close to the axis of symmetry, wherein an angle between the innermost edge and the first extension edge of the outermost flux barrier is less than 90°.

[0011] Optionally, either one of the first extension edge and the second extension edge extends in an arc or a straight line.

[0012] Optionally, a cross section of the middle flux barrier comprises an innermost edge closest to the center of the rotor, an outermost edge furthest from the center of the rotor, and a first arc-shaped extension edge and a second arc-shaped extension edge extending between end points of the innermost edge and the outermost edge, a length of the first arc-shaped extension edge being greater than a length of the second arc-shaped extension edge, wherein a length of the outermost edge of the middle flux barrier is greater than a length of the innermost edge of the outermost flux barrier of the same arc-shaped flux barrier layer.

[0013] Optionally, the first extension edge of the outermost flux barrier is not parallel to an extension line of the first arc-shaped extension edge of the middle flux barrier of the same arc-shaped flux barrier layer, and an angle between the innermost edge and the first extension edge of the outermost flux barrier is less than an angle between the innermost edge of the outermost flux barrier and a parallel line of the extension line of the first arc-shaped extension edge of the middle flux barrier of the same arc-shaped flux barrier layer.

[0014] Optionally, an end of the innermost edge of the outermost flux barrier which is remote from the axis of symmetry is located at one side of the extension line of the first arc-shaped extension edge of the middle flux barrier, said side being close to the axis of symmetry.

[0015] Optionally, distances between corresponding flux barriers in two adjacent arc-shaped flux barrier layers satisfy the following relationships: a minimum distance between the outermost flux barriers is greater than a minimum distance between the middle flux barriers, and a minimum distance between the innermost flux barriers is greater than a maximum distance between the middle flux barriers.

[0016] Optionally, extension lengths of the middle flux barriers of each arc-shaped flux barrier layer can be adjusted independently of extension lengths of the middle flux barriers in the other arc-shaped flux barrier layers.

[0017] Optionally, the magnetic substance is formed by mixing particles of a magnetic material and particles of a plastic, the magnetic material comprising at least one of SmFeN, NdFeB and ferrite, and the plastic comprising at least one of PA12 (polylaurolactam), PP (polypropylene) and PPS (polyphenylene sulfide). Optionally, each flux barrier structure comprises three arc-shaped flux barrier layers, the three arc-shaped flux barrier layers comprising an innermost arc-shaped flux barrier layer closest to the center of the rotor, an outermost arc-shaped flux barrier layer furthest from the center of the rotor, and a middle arc-shaped flux barrier layer located between the innermost arc-shaped flux barrier layer and the outermost arc-shaped flux barrier layer.

[0018] 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.

[0019] The rotor and the synchronous reluctance motor comprising said rotor according to the present invention can achieve at least one of the following advantages:

[0020] In the present invention, the rotor has an even number of flux barrier structures, each flux barrier structure comprising multiple arc-shaped flux barrier layers, the multiple arc-shaped flux barrier layers of each flux barrier structure having the same axis of symmetry, each arc-shaped flux barrier layer comprising five flux barriers, the two outermost flux barriers being symmetric to each other with respect to the axis of symmetry, the two middle flux barriers being symmetric to each other with respect to the axis of symmetry, and the innermost flux barrier itself being symmetric with respect to the axis of symmetry. Thus, the multi-layer flux barrier design with the same axis of symmetry can help to fully utilize the reluctance torque of the electric motor, so as to improve the output performance thereof. In addition, the two outermost flux barriers are not filled with a magnetic substance, so that the magnetic substance is remote from the stator windings to reduce the risk of the magnetic substance being demagnetized.

[0021] In the present invention, the angle between the axis of symmetry and a straight line passing through the center of the magnetic bridge between the outermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°, and the angle between the axis of symmetry and a straight line passing through the center of the magnetic bridge between the innermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°; this can help to fully utilize the reluctance torque of the electric motor, so as to improve the output performance thereof.

[0022] In the present invention, the angle between the innermost edge and the first extension edge of the outermost flux barrier is less than 90°; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0023] In the present invention, the length of the outermost edge of the middle flux barrier is greater than the length of the innermost edge of the outermost flux barrier of the same arc-shaped flux barrier layer; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0024] In the present invention, the first extension edge of the outermost flux barrier is not parallel to an extension line of the first arc-shaped extension edge of the middle flux barrier of the same arc-shaped flux barrier layer, and the first extension edge of the outermost flux barrier is more inclined in the direction of the axis of symmetry than the first arc-shaped extension edge of the middle flux barrier of the same arc-shaped flux barrier layer; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0025] In the present invention, in the case of two adjacent arc-shaped flux barrier layers, the minimum distance between the outermost flux barriers is greater than the minimum distance between the middle flux barriers, and the minimum distance between the innermost flux barriers is greater than the maximum distance between the middle flux barriers; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0026] In the present invention, the extension lengths of the middle flux barriers of each arc-shaped flux barrier layer can be adjusted independently of the extension lengths of the middle flux barriers in the other arc-shaped flux barrier layers, thus making it possible to optimize the output performance of the electric motor according to actual needs. In the present invention, the magnetic substance is formed by mixing particles of a magnetic material (e.g. SmFeN, NdFeB or ferrite) and particles of a plastic (e.g. PA12, PP or PPS), so as to achieve the desired electric motor performance while taking into account the cost and operating environment of the electric motor.

[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, so should not be regarded as limiting the present application, and are referred to below to give a detailed description, 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.

[0031] Figs. 3 - 7 each show a portion of a rotor of a synchronous reluctance motor according to a particular embodiment of the present invention.

[0032] Detailed Description of the Invention

[0033] 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. Fig. 2 shows a rotor of a synchronous reluctance motor according to a particular embodiment of the present invention. Figs. 3 - 7 each show a portion of a rotor of a synchronous reluctance motor according to a particular embodiment of the present invention.

[0034] As shown in Figs. 2 - 7, the rotor may be formed by stacking silicon steel sheets; and through-holes, i.e. flux barriers, are punched in the silicon steel sheets. The rotor has an even number of flux barrier structures 1 arranged in a circumferential direction of the rotor, wherein each flux barrier structure comprises three arc-shaped flux barrier layers which open toward an edge of the rotor, specifically, an innermost arc-shaped flux barrier layer 11 that is closest to the center of the rotor, an outermost arc-shaped flux barrier layer 13 that is furthest from the center of the rotor, and a middle arc-shaped flux barrier layer 12 located between the innermost arc-shaped flux barrier layer 11 and the outermost arc-shaped flux barrier layer 13. The three arc-shaped flux barrier layers of each flux barrier structure have the same axis of symmetry. For example, the axis of symmetry of the three arc-shaped flux barrier layers in Fig. 3 is the axis OX; preferably, the axis OX extends in a diametric direction of the rotor.

[0035] As shown in Fig. 3, each arc-shaped flux barrier layer comprises five flux barriers, specifically, two outermost flux barriers 101 and 105 which are furthest from the center of the rotor, one innermost flux barrier 103 which is closest to the center of the rotor, and two middle flux barriers 102 and 104 located between the innermost flux barrier and the outermost flux barriers. The two outermost flux barriers 101 and 105 are symmetric to each other with respect to the axis OX, the two middle flux barriers 102 and 104 are symmetric to each other with respect to the axis OX, and the innermost flux barrier 103 is itself symmetric with respect to the axis OX. A magnetic bridge is provided between two adjacent flux barriers; specifically, a magnetic bridge L1 is provided between flux barriers 101 and 102, a magnetic bridge L2 is provided between flux barriers 102 and 103, a magnetic bridge L3 is provided between flux barriers 103 and 104, and a magnetic bridge L4 is provided between flux barriers 104 and 105, the four magnetic bridges L1 , L2, L3 and L4 being distributed symmetrically at two sides of the axis OX. As also shown in Fig. 3, the two outermost flux barriers 101 and 105 are not filled with a magnetic substance, the two middle flux barriers 102 and 104 are filled with a magnetic substance (the black parts in the figure), and the innermost flux barrier 103 is not filled with a magnetic substance. However, depending on actual needs, it is also possible for the innermost flux barrier 103 to be filled with a magnetic substance; these variants do not exceed the scope of protection of the present invention.

[0036] As shown in Fig. 4, an angle a between the axis OX and a straight line P1 passing through the center of the magnetic bridge L1 between the outermost flux barrier 101 and the middle flux barrier 102 of the same arc-shaped flux barrier layer is less than 90°, and an angle [3 between the axis OX and a straight line P2 passing through the center of the magnetic bridge L2 between the innermost flux barrier 103 and the middle flux barrier 102 of the same arc-shaped flux barrier layer is less than 90°.

[0037] As shown in Fig. 5, a cross section of the outermost flux barrier 101 comprises an innermost edge 1011 that is closest to the center of the rotor, an outermost edge 1014 that is furthest from the center of the rotor, and a first extension edge 1012 and a second extension edge 1013 extending between end points of the innermost edge and the outermost edge. The first extension edge 1012 extends between that end of the innermost edge 1011 which is remote from the axis of symmetry and that end of the outermost edge 1014 which is remote from the axis of symmetry, and the second extension edge 1013 extends between that end of the innermost edge 1011 which is close to the axis of symmetry and that end of the outermost edge 1014 which is close to the axis of symmetry, so that the first extension edge 1012 is further from the axis of symmetry of the arc-shaped flux barrier layer in which it lies, and the second extension edge 1013 is closer to the axis of symmetry of the arc-shaped flux barrier layer in which it lies. An angle 9 between the innermost edge 1011 and the first extension edge 1012 is less than 90°. Either one of the first extension edge 1012 and the second extension edge 1013 may extend in an arc or a straight line.

[0038] Also as shown in Fig. 5, a cross section of the middle flux barrier 102 comprises an innermost edge 1021 that is closest to the center of the rotor, an outermost edge 1024 that is furthest from the center of the rotor, and a first arc-shaped extension edge 1022 and a second arc-shaped extension edge 1023 extending between end points of the innermost edge and the outermost edge. The first arc-shaped extension edge 1022 extends between that end of the innermost edge 1021 which is remote from the axis of symmetry and that end of the outermost edge 1024 which is remote from the axis of symmetry, and the second arc-shaped extension edge 1023 extends between that end of the innermost edge 1021 which is close to the axis of symmetry and that end of the outermost edge 1024 which is close to the axis of symmetry. The length of the first arc-shaped extension edge 1022 is greater than the length of the second arc-shaped extension edge 1023.

[0039] As shown more clearly in Fig. 6, the length D1 of the outermost edge 1024 of the middle flux barrier 102 is greater than the length D2 of the innermost edge 1011 of the outermost flux barrier 101. The first extension edge 1012 of the outermost flux barrier 101 is not parallel to an extension line A1 of the first arc-shaped extension edge 1022 of the middle flux barrier 102. More specifically, as shown in Fig. 6, the angle 9 between the innermost edge 1011 and the first extension edge 1012 of the outermost flux barrier 101 is less than an angle between the innermost edge 1011 and a parallel line A2 of the extension line A1 of the first arc-shaped extension edge 1022 of the middle flux barrier 102. In addition, that end of the innermost edge 1011 of the outermost flux barrier 101 which is remote from the axis of symmetry is located at one side of the extension line A1 of the first arc-shaped extension edge 1022 of the middle flux barrier 102, said side being close to the axis of symmetry (for example, the parallel line A2 passing through that end of the innermost edge 1011 which is remote from the axis of symmetry is located at the side of the extension line A1 which is close to the axis of symmetry). Thus, relative to the first arc-shaped extension edge 1022 of the middle flux barrier 102, the first extension edge 1012 of the outermost flux barrier 101 is more inclined towards the axis of symmetry.

[0040] Also as shown in Fig. 5, distances between corresponding flux barriers in two adjacent arc-shaped flux barrier layers satisfy the following relationships: a minimum distance M between the outermost flux barriers closest to the rotor edge is greater than a minimum distance N between the middle flux barriers, and a minimum distance H between the innermost flux barriers closest to the rotor center is greater than a maximum distance K between the middle flux barriers.

[0041] In the present invention, the extension lengths of the middle flux barriers in each arc-shaped flux barrier layer can be adjusted independently of the extension lengths of the middle flux barriers in the other arc-shaped flux barrier layers; therefore, the positions of corresponding magnetic bridges of different arc-shaped flux barrier layers may be different or the same, i.e. corresponding magnetic bridges of different arc-shaped flux barrier layers may be aligned or not aligned with each other. For example, as shown in Fig. 7, the magnetic bridge L1 of the outermost flux barrier layer 13 is aligned with the magnetic bridge L1 of the middle flux barrier layer 12, but the magnetic bridge L1 of the innermost flux barrier layer 11 is not aligned with the magnetic bridge L1 of the middle flux barrier layer 12.

[0042] In the present invention, 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 distributed uniformly in the circumferential direction of the rotor. The number of flux barrier structures 1 could also be greater or less than 8; the number n thereof may satisfy the formula: n = 2p, where p is a positive integer. These variants do not exceed the scope of protection of the present invention.

[0043] In the present invention, the specific shape of the 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 being a hyperbola, a circular arc or a parabola, etc.; these variants do not exceed the scope of protection of the present invention.

[0044] In the present invention, 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.

[0045] In the present invention, 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.

[0046] In the present invention, the specific number of multiple arc-shaped flux barrier layers in each flux barrier structure may be set according to actual needs; for example, each flux barrier structure shown in Figs. 2 - 7 comprises three arc-shaped flux barrier layers, but the number of arc-shaped flux barrier layers could also be greater or less than 3, e.g. 2 or 4, and these variants do not exceed the scope of protection of the present invention. Comprehensively taking into account the electric motor's output performance, mechanical strength and risk of demagnetization, it is preferred that each flux barrier structure may comprise three arc-shaped flux barrier layers.

[0047] 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:

[0048] In the present invention, the rotor has multiple flux barrier structures, each flux barrier structure comprising multiple arc-shaped flux barrier layers, the multiple arc-shaped flux barrier layers of each flux barrier structure having the same axis of symmetry, each arc-shaped flux barrier layer comprising five flux barriers, the two outermost flux barriers being symmetric to each other with respect to the axis of symmetry, the two middle flux barriers being symmetric to each other with respect to the axis of symmetry, and the innermost flux barrier itself being symmetric with respect to the axis of symmetry. Thus, the multi-layer flux barrier design with the same axis of symmetry can help to fully utilize the reluctance torque of the electric motor, so as to improve the output performance thereof. In addition, the two outermost flux barriers are not filled with a magnetic substance, so that the magnetic substance is remote from the stator windings to reduce the risk of the magnetic substance being demagnetized.

[0049] In the present invention, the angle between the axis of symmetry and a straight line passing through the center of the magnetic bridge between the outermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°, and the angle between the axis of symmetry and a straight line passing through the center of the magnetic bridge between the innermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°; this can help to fully utilize the reluctance torque of the electric motor, so as to improve the output performance thereof.

[0050] In the present invention, the angle between the innermost edge and the first extension edge of the outermost flux barrier is less than 90°; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0051] In the present invention, the length of the outermost edge of the middle flux barrier is greater than the length of the innermost edge of the outermost flux barrier of the same arc-shaped flux barrier layer; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0052] In the present invention, the first extension edge of the outermost flux barrier is not parallel to an extension line of the first arc-shaped extension edge of the middle flux barrier of the same arc-shaped flux barrier layer, and the first extension edge of the outermost flux barrier is more inclined in the direction of the axis of symmetry than the first arc-shaped extension edge of the middle flux barrier of the same arc-shaped flux barrier layer; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0053] In the present invention, in the case of two adjacent arc-shaped flux barrier layers, the minimum distance between the outermost flux barriers is greater than the minimum distance between the middle flux barriers, and the minimum distance between the innermost flux barriers is greater than the maximum distance between the middle flux barriers; this can effectively reduce the risk of the magnetic substance being demagnetized.

[0054] In the present invention, the extension lengths of the middle flux barriers of each arc-shaped flux barrier layer can be adjusted independently of the extension lengths of the middle flux barriers in the other arc-shaped flux barrier layers, thus making it possible to optimize the output performance of the electric motor according to actual needs.

[0055] In the present invention, the magnetic substance is formed by mixing particles of a magnetic material (e.g. SmFeN, NdFeB and ferrite) and particles of a plastic (e.g. PA12, PP and PPS), so as to achieve the desired electric motor performance while taking into account the cost and operating environment of the electric motor.

[0056] 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

Patent claims1 . A rotor, wherein the rotor has an even number of flux barrier structures (1 ) arranged in a circumferential direction of the rotor, each flux barrier structure comprising multiple arc-shaped flux barrier layers which open toward an edge of the rotor, the multiple arc-shaped flux barrier layers of each flux barrier structure having the same axis of symmetry (OX), wherein each arc-shaped flux barrier layer comprises five flux barriers, with a magnetic bridge provided between two adjacent flux barriers, wherein the five flux barriers comprise an innermost flux barrier (103) closest to the center of the rotor, two outermost flux barriers (101 , 105) furthest from the center of the rotor, and two middle flux barriers (102, 104) located between the innermost flux barrier and the outermost flux barriers, wherein the two outermost flux barriers are symmetric to each other with respect to the axis of symmetry, the two middle flux barriers are symmetric to each other with respect to the axis of symmetry, and the innermost flux barrier is itself symmetric with respect to the axis of symmetry, wherein the two outermost flux barriers are not filled with a magnetic substance, the two middle flux barriers are filled with a magnetic substance, and the innermost flux barrier is filled or not filled with a magnetic substance.

2. The rotor as claimed in claim 1 , wherein an angle (a) between the axis of symmetry and a straight line (P1 ) passing through the center of a magnetic bridge (L1 ) between the outermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°, and an angle ([3) between the axis of symmetry and a straight line (P2) passing through the center of a magnetic bridge (L2) between the innermost flux barrier and the middle flux barrier of the same arc-shaped flux barrier layer is less than 90°.

3. The rotor as claimed in claim 1 , wherein a cross section of the outermost flux barrier comprises an innermost edge (1011 ) closest to the center of the rotor, an outermost edge (1014) furthest from the center of the rotor, and a first extension edge (1012) and a second extension edge (1013) extending between end points of the innermost edge and the outermost edge, the first extension edge being remote from the axis of symmetry and the second extension edge being close to the axis of symmetry, wherein an angle (9) between the innermost edge (1011 ) and the first extension edge (1012) of the outermost flux barrier is less than 90°.

4. The rotor as claimed in claim 3, wherein either one of the first extension edge (1012) and the second extension edge (1013) extends in an arc or a straight line.

5. The rotor as claimed in claim 3, wherein a cross section of the middle flux barrier comprises an innermost edge (1021 ) closest to the center of the rotor, an outermost edge (1024) furthest from the center of the rotor, and a first arc-shaped extension edge (1022) and a second arc-shaped extension edge (1023) extending between end points of the innermost edge and the outermost edge, a length of the first arc-shaped extension edge being greater than a length of the second arc-shaped extension edge, wherein a length (D1 ) of the outermost edge of the middle flux barrier is greater than a length (D2) of the innermost edge of the outermost flux barrier of the same arc-shaped flux barrier layer.

6. The rotor as claimed in claim 5, wherein the first extension edge (1012) of the outermost flux barrier is not parallel to an extension line (A1 ) of the first arc-shaped extension edge (1022) of the middle flux barrier of the same arc-shaped flux barrier layer, and an angle (9) between the innermost edge (1011 ) and the first extension edge (1012) of the outermost flux barrier is less than an angle between the innermost edge (1011 ) of the outermost flux barrier and a parallel line (A2) of the extension line (A1 ) of the first arc-shaped extension edge (1022) of the middle flux barrier of the same arc-shaped flux barrier layer.

7. The rotor as claimed in claim 6, wherein an end of the innermost edge (1011 ) of the outermost flux barrier which is remote from the axis of symmetry is located at one side of the extension line (A1 ) of the first arc-shaped extension edge (1022) of the middle flux barrier, said side being close to the axis of symmetry.

8. The rotor as claimed in claim 1 , wherein distances between corresponding flux barriers in two adjacent arc-shaped flux barrier layers satisfy the following relationships: a minimum distance (M) between the outermost flux barriers is greater than a minimum distance (N) between the middle flux barriers, and a minimum distance (H) between the innermost flux barriers is greater than a maximum distance (K) between the middle flux barriers.

9. The rotor as claimed in claim 1 , wherein extension lengths of the middle flux barriers of each arc-shaped flux barrier layer can be adjusted independently of extension lengths of the middle flux barriers in the other arc-shaped flux barrier layers.

10. The rotor as claimed in claim 1 , wherein the magnetic substance is formed by mixing particles of a magnetic material and particles of a plastic, the magnetic material comprising at least one of SmFeN, NdFeB and ferrite, and the plastic comprising at least one of PA12, PP and PPS.11 . The rotor as claimed in claim 1 , wherein each flux barrier structure comprises three arc-shaped flux barrier layers, the three arc-shaped flux barrier layers comprising an innermost arc-shaped flux barrier layer (11 ) closest to the center of the rotor, an outermost arc-shaped flux barrier layer (13) furthest from the center of the rotor, and a middle arc-shaped flux barrier layer (12) located between the innermost arc-shaped flux barrier layer and the outermost arc-shaped flux barrier layer.

12. A synchronous reluctance motor, wherein the synchronous reluctance motor comprises a stator and the rotor as claimed in any one of claims 1 - 11 , the stator being provided with a winding.

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