Rotor and permanent magnet synchronous motor having same

Abstract

The present invention discloses a rotor and a permanent magnet synchronous motor having same. In the present invention, each flux barrier structure of the rotor comprises the first arc-shaped flux barrier layer closest to the edge of the rotor, and the second flux barrier layer which is closer than the first arc-shaped flux barrier layer to the center of the rotor. Injection-molded permanent magnets are provided in the first arc-shaped flux barrier layer, and the price of the injection-molded permanent magnets is lower than that of sintered permanent magnets, thereby lowering costs. Although the injection-molded permanent magnets have weaker magnetic performance, the arc-shaped flux barrier layer design helps to fully utilize the reluctance torque of the electric motor, thereby compensating for the drop in magnetic performance to a certain extent. In addition, sintered permanent magnets with stronger magnetic performance are provided in the second flux barrier layer, thereby ensuring that the rotor has sufficient magnetic performance to achieve the desired electric motor performance.

Description

[0001] Description

[0002] Rotor and permanent magnet synchronous motor having same

[0003] Technical Field

[0004] The present invention relates to the technical field of electric motors, in particular to a rotor, and a permanent magnet synchronous motor having same.

[0005] Background Art

[0006] As the development of new energy vehicles advances, drive motors are subject to ever higher performance requirements. Permanent magnet synchronous motors are characterized by low cost and high utilization of reluctance torque, and have gradually attracted the attention of motor vehicle manufacturers.

[0007] A permanent magnet synchronous motor comprises a stator and a rotor; windings are arranged on the stator, while sintered permanent magnets (i.e. magnetic steel) made of rare earth materials (such as NdFeB) are arranged on the rotor. The sintered permanent magnets are generally cuboid-shaped. Correspondingly, slots are provided in the rotor. The sintered permanent magnets are inserted in the slots.

[0008] However, because the sintered permanent magnets are cuboid-shaped, the reluctance torque of the electric motor cannot be fully utilized, and a large number of sintered permanent magnets are needed to provide permanent magnet torque. That is to say, to achieve the same output performance, the permanent magnet synchronous motor has more sintered permanent magnets than in theory, and a higher cost. In addition, due to the high strength of the magnetic field close to the stator windings, the permanent magnets close to the rotor edge (i.e. closest to the stator windings) are at risk of being demagnetized.

[0009] Summary of the Invention

[0010] The objective of the present invention is to provide a rotor and a permanent magnet synchronous motor with the rotor, thereby solving the abovementioned problems in the prior art.

[0011] 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 flux barrier layers, the multiple flux barrier layers of each flux barrier structure having the same axis of symmetry, wherein the multiple flux barrier layers comprise a first arc-shaped flux barrier layer closest to an edge of the rotor, and a second flux barrier layer which is closer than the first arc-shaped flux barrier layer to the center of the rotor, wherein an opening of the first arc-shaped flux barrier layer faces toward the edge of the rotor, and the first arc-shaped flux barrier layer comprises five slots, with flux bridges provided between two adjacent slots, wherein the five slots comprise a first slot closest to the center of the rotor, a second slot and a third slot which are furthest from the center of the rotor, a fourth slot located between the first slot and the second slot, and a fifth slot located between the first slot and the third slot, wherein the second slot and the third slot are symmetric with respect to the axis of symmetry, the fourth slot and the fifth slot are symmetric with respect to the axis of symmetry, and the first slot is itself symmetric with respect to the axis of symmetry, wherein the second flux barrier layer comprises three slots, with flux bridges provided between two adjacent slots, wherein the three slots comprise a sixth slot closest to the center of the rotor, and a seventh slot and an eighth slot which are remote from the center of the rotor, wherein the seventh slot and the eighth slot are symmetric with respect to the axis of symmetry, the sixth slot is itself symmetric with respect to the axis of symmetry, and a distance between the seventh slot and the eighth slot gradually increases in a direction away from the center of the rotor, wherein injection-molded permanent magnets are packed in the fourth slot and the fifth slot, and sintered permanent magnets are packed in the seventh slot and the eighth slot.

[0012] Optionally, no permanent magnets are packed in the second slot and the third slot, and no permanent magnets are packed in spaces separating the sintered permanent magnets from edges of the seventh slot and the eighth slot that are remote from the center of the rotor.

[0013] Optionally, injection-molded permanent magnets are packed in spaces separating the sintered permanent magnets from edges of the seventh slot and the eighth slot that are close to the center of the rotor.

[0014] Optionally, the multiple arc-shaped flux barrier layers further comprise a third arcshaped flux barrier layer, wherein the third arc-shaped flux barrier layer is closer than the second flux barrier layer to the center of the rotor, or the third arc-shaped flux barrier layer is located between the first arc-shaped flux barrier layer and the second flux barrier layer.

[0015] Optionally, an opening of the third arc-shaped flux barrier layer faces toward the edge of the rotor, and the third arc-shaped flux barrier layer comprises five slots, with flux bridges provided between two adjacent slots, wherein the five slots comprise a ninth slot closest to the center of the rotor, a tenth slot and an eleventh slot which are furthest from the center of the rotor, a twelfth slot located between the ninth slot and the tenth slot, and a thirteenth slot located between the ninth slot and the eleventh slot, wherein the tenth slot and the eleventh slot are symmetric with respect to the axis of symmetry, the twelfth slot and the thirteenth slot are symmetric with respect to the axis of symmetry, and the ninth slot is itself symmetric with respect to the axis of symmetry, wherein injection-molded permanent magnets are packed in the twelfth slot and the thirteenth slot, and no permanent magnets are packed in the tenth slot and the eleventh slot.

[0016] Optionally, the sintered permanent magnet is made of NdFeB.

[0017] Optionally, the injection-molded permanent magnet is formed by mixing particles of a magnetic material and particles of a plastic, the mass ratio of the particles of the magnetic material to the particles of the plastic being adjustable.

[0018] Optionally, the magnetic material comprises at least one of SmFeN and NdFeB, and the plastic comprises at least one of PA12, PP and PPS.

[0019] Optionally, widths of the flux bridges are adjustable. According to a second aspect of the present invention, a permanent magnet synchronous motor is provided, the permanent magnet synchronous motor comprising a stator on which a winding is provided, and the rotor according to the first aspect of the present invention.

[0020] The rotor and the permanent magnet synchronous motor having same according to the present invention can achieve at least one of the following advantages:

[0021] In the present invention, each flux barrier structure of the rotor comprises the first arc-shaped flux barrier layer closest to the edge of the rotor, and the second flux barrier layer which is closer than the first arc-shaped flux barrier layer to the center of the rotor. Injection-molded permanent magnets are provided in the first arcshaped flux barrier layer, and the price of the injection-molded permanent magnets is lower than that of sintered permanent magnets, thereby lowering costs. Although the injection-molded permanent magnets have weaker magnetic performance, the arc-shaped flux barrier layer design helps to fully utilize the reluctance torque of the electric motor, thereby compensating for the drop in magnetic performance to a certain extent. In addition, sintered permanent magnets with stronger magnetic performance are provided in the second flux barrier layer, thereby ensuring that the rotor has sufficient magnetic performance to achieve the desired electric motor performance.

[0022] In the present invention, it is possible to have no permanent magnets packed at positions close to the edge of the rotor (i.e. in the second slot and the third slot of the first arc-shaped flux barrier layer which are furthest from the center of the rotor, and in the spaces separating the sintered permanent magnets from the edges of the seventh and eighth slots of the second flux barrier layer which are remote from the center of the rotor), so that the permanent magnets are separated from the stator windings by a certain distance, thereby reducing the risk of the permanent magnets being demagnetized.

[0023] In the present invention, injection-molded permanent magnets may be packed in the spaces separating the sintered permanent magnets from the edges of the seventh and eighth slots of the second flux barrier layer that are close to the center of the rotor, thereby further enhancing the magnetic performance of the rotor. In the present invention, the rotor may further comprise the third arc-shaped flux barrier layer, thereby further enhancing the magnetic performance of the rotor.

[0024] In the present invention, the injection-molded permanent magnets are formed by mixing particles of magnetic material with particles of plastic, and the mass ratio of the particles of magnetic material to the particles of plastic can be adjusted, thereby making it possible to adjust the physical properties and magnetic performance of the injection-molded permanent magnets according to actual needs.

[0025] In the present invention, the magnetic material may comprise at least one of SmFeN and NFeB, and the plastic may be selected from at least one of PA12 (polylaurolactam), PP (polypropylene) and PPS (polyphenylene sulfide); it is thus possible to achieve the desired electric motor performance while taking into account costs and operating environment.

[0026] In the present invention, the widths of the flux bridges can be adjusted, thus enabling adjustment of electric motor performance according to actual needs.

[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 rotor of a permanent magnet synchronous motor according to a first particular embodiment of the present invention.

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

[0031] Fig. 3 shows a portion of a rotor of a permanent magnet synchronous motor according to a second particular embodiment of the present invention.

[0032] Detailed Description of the Invention 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. 1 shows a rotor of a permanent magnet synchronous motor according to a particular embodiment of the present invention. Fig. 2 shows a portion of a rotor of a permanent magnet synchronous motor according to a first particular embodiment of the present invention.

[0034] As shown in Figs. 1 and 2, the rotor may be formed by stacking silicon steel sheets, in which through-holes slots are punched. 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 flux barrier layers, the multiple flux barrier layers of each flux barrier structure having the same axis of symmetry. The axis of symmetry preferably extends in a diametric direction of the rotor.

[0035] Still as shown in Figs. 1 and 2, the multiple flux barrier layers comprise a first arcshaped flux barrier layer 11 closest to an edge of the rotor, and a second flux barrier layer 12 which is closer than the first arc-shaped flux barrier layer 11 to the center of the rotor.

[0036] An opening of the first arc-shaped flux barrier layer 11 faces toward the edge of the rotor. The first arc-shaped flux barrier layer 11 comprises five slots 11 1 , 112, 113, 114 and 115, with flux bridges provided between two adjacent slots. The five slots comprise a first slot 111 closest to the center of the rotor, a second slot 112 and a third slot 113 which are furthest from the center of the rotor, a fourth slot 114 located between the first slot 111 and the second slot 112, and a fifth slot 115 located between the first slot 111 and the third slot 113. The second slot 112 and the third slot 113 are symmetric with respect to the axis of symmetry; the fourth slot 114 and the fifth slot 115 are symmetric with respect to the axis of symmetry; and the first slot 111 is itself symmetric with respect to the axis of symmetry.

[0037] The second flux barrier layer 12 comprises three slots, with flux bridges provided between two adjacent slots. The three slots comprise a sixth slot 121 closest to the center of the rotor, and a seventh slot 122 and an eighth slot 123 which are remote from the center of the rotor. The seventh slot 122 and the eighth slot 123 are symmetric with respect to the axis of symmetry, the sixth slot 121 is itself symmetric with respect to the axis of symmetry, and the distance between the seventh slot 122 and the eighth slot 123 gradually increases in a direction away from the center of the rotor, such that the seventh slot 122 and the eighth slot 123 form an opening that gradually increases in size toward the rotor edge in a cross section of the rotor.

[0038] Injection-molded permanent magnets (the black parts in the figures) are packed in the fourth slot 114 and the fifth slot 115, and sintered permanent magnets (the red parts in the figures) are packed in the seventh slot 122 and the eighth slot 123.

[0039] The price of the injection-molded permanent magnets is lower than that of the sintered permanent magnets, so costs are reduced. Although the injection-molded permanent magnets have weaker magnetic performance, the arc-shaped design of the first flux barrier layer 11 helps to fully utilize the reluctance torque of the electric motor, thereby compensating for the drop in magnetic performance to a certain extent; furthermore, the sintered permanent magnets with stronger magnetic performance provided in the second flux barrier layer 12 ensure that the rotor has sufficient magnetic performance to achieve the desired electric motor performance.

[0040] Still as shown in Figs. 1 and 2, no permanent magnets are packed in the second slot 112 and the third slot 113, and no permanent magnets are packed in spaces separating the sintered permanent magnets from edges of the seventh slot 122 and eighth slot 123 which are remote from the center of the rotor. This ensures that the permanent magnets are separated from the stator windings by a certain distance, thereby reducing the risk of demagnetization of the permanent magnets. Still as shown in Figs. 1 and 2, injection-molded permanent magnets are packed in spaces separating the sintered permanent magnets from edges of the seventh slot 122 and eighth slot 123 which are close to the center of the rotor. This further enhances the magnetic performance of the rotor.

[0041] Still as shown in Figs. 1 and 2, the rotor may further comprise a third arc-shaped flux barrier layer 13 closer than the second flux barrier layer 12 to the center of the rotor, thereby further enhancing the magnetic performance of the rotor. An opening of the third arc-shaped flux barrier layer 13 faces toward the edge of the rotor, and the third arc-shaped flux barrier layer 13 comprises five slots, with flux bridges provided between two adjacent slots. The five slots comprise a ninth slot 131 closest to the center of the rotor, a tenth slot 132 and an eleventh slot 133 which are furthest from the center of the rotor, a twelfth slot 134 located between the ninth slot 131 and the tenth slot 132, and a thirteenth slot 135 located between the ninth slot 131 and the eleventh slot 133. The tenth slot 132 and the eleventh slot 133 are symmetric with respect to the axis of symmetry, the twelfth slot 134 and the thirteenth slot 135 are symmetric with respect to the axis of symmetry, and the ninth slot 131 is itself symmetric with respect to the axis of symmetry. Injection-molded permanent magnets (the black parts in the figure) are packed in the twelfth slot 134 and the thirteenth slot 135; no permanent magnets are packed in the tenth slot 132 and the eleventh slot 133.

[0042] Still as shown in Figs. 1 and 2, no permanent magnets are packed in the first slot 111 , the sixth slot 121 and the ninth slot 131. However, depending on actual needs, it is also possible for permanent magnets to be packed in the first slot 111 , the sixth slot 121 and the ninth slot 131 , and these variants do not exceed the scope of protection of the present invention.

[0043] In the first particular embodiment of the present invention shown in Figs. 1 and 2, the third arc-shaped flux barrier layer 13 is closer than the second flux barrier layer 12 to the center of the rotor. However, those skilled in the art will understand that the third arc-shaped flux barrier layer 13 could also be arranged in other suitable positions, and these variants do not exceed the scope of protection of the present invention. For example, Fig. 3 shows a portion of a rotor of a permanent magnet synchronous motor according to a second particular embodiment of the present invention. As shown in Fig. 3, the third arc-shaped flux barrier layer 13 may be located between the first arc-shaped flux barrier layer 11 and the second flux barrier layer 12.

[0044] In the present invention, the sintered permanent magnets may be formed by sintering any suitable material, and these variants do not exceed the scope of protection of the present invention. Preferably, the sintered permanent magnets are made of a rare earth material with stronger magnetic performance, such as NdFeB.

[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 and NdFeB, may be used. Due to being lower-priced, SmFeN can further reduce the cost of the permanent magnet synchronous motor. 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 widths of the flux bridges can be adjusted, thus enabling adjustment of electric motor performance according to actual needs.

[0047] 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. 1 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.

[0048] 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.

[0049] In the present invention, the specific number of 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. 1 - 3 comprises three flux barrier layers, but the number of flux barrier layers could also be greater or less than 3, e.g. 2 or 4, as long as it is ensured that the rotor comprises the first arc-shaped flux barrier layer and the second flux barrier layer of the present invention, and these variants do not exceed the scope of protection of the present invention. Preferably, the rotor comprises the three flux barrier layers shown in Figs. 1 - 3, to realize better performance and mechanical properties.

[0050] Compared with the prior art, the rotor and the permanent magnet synchronous motor having same in embodiments of the present invention have at least the following advantages:

[0051] In the present invention, each flux barrier structure of the rotor comprises the first arc-shaped flux barrier layer closest to the edge of the rotor, and the second flux barrier layer which is closer than the first arc-shaped flux barrier layer to the center of the rotor. Injection-molded permanent magnets are provided in the first arcshaped flux barrier layer, and the price of the injection-molded permanent magnets is lower than that of sintered permanent magnets, thereby lowering costs. Although the injection-molded permanent magnets have weaker magnetic performance, the arc-shaped flux barrier layer design helps to fully utilize the reluctance torque of the electric motor, thereby compensating for the drop in magnetic performance to a certain extent. In addition, sintered permanent magnets with stronger magnetic performance are provided in the second flux barrier layer, thereby ensuring that the rotor has sufficient magnetic performance to achieve the desired electric motor performance.

[0052] In the present invention, it is possible to have no permanent magnets packed at positions close to the edge of the rotor (i.e. in the second slot and the third slot of the first arc-shaped flux barrier layer which are furthest from the center of the rotor, and in the spaces separating the sintered permanent magnets from the edges of the seventh and eighth slots of the second flux barrier layer which are remote from the center of the rotor), so that the permanent magnets are separated from the stator windings by a certain distance, thereby reducing the risk of the permanent magnets being demagnetized. In the present invention, injection-molded permanent magnets may be packed in the spaces separating the sintered permanent magnets from the edges of the seventh and eighth slots of the second flux barrier layer that are close to the center of the rotor, thereby further enhancing the magnetic performance of the rotor.

[0053] In the present invention, the rotor may further comprise the third arc-shaped flux barrier layer, thereby further enhancing the magnetic performance of the rotor.

[0054] In the present invention, the injection-molded permanent magnets are formed by mixing particles of magnetic material with particles of plastic, and the mass ratio of the particles of magnetic material to the particles of plastic can be adjusted, thereby making it possible to adjust the physical properties and magnetic performance of the injection-molded permanent magnets according to actual needs.

[0055] In the present invention, the magnetic material may comprise at least one of SmFeN and NFeB, and the plastic may be selected from at least one of PA12, PP or PPS; it is thus possible to achieve the desired electric motor performance while taking into account costs and operating environment.

[0056] In the present invention, the widths of the flux bridges can be adjusted, thus enabling adjustment of electric motor performance according to actual needs.

[0057] Although the present invention has been disclosed above in preferred embodiments, it is not limited to this. Various changes and modifications made by a person 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, characterized in that 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 flux barrier layers, the multiple flux barrier layers of each flux barrier structure having the same axis of symmetry, wherein the multiple flux barrier layers comprise a first arc-shaped flux barrier layer (11 ) closest to an edge of the rotor, and a second flux barrier layer (12) which is closer than the first arc-shaped flux barrier layer (11 ) to the center of the rotor, wherein an opening of the first arc-shaped flux barrier layer (11 ) faces toward the edge of the rotor, and the first arc-shaped flux barrier layer (11 ) comprises five slots, with flux bridges provided between two adjacent slots, wherein the five slots comprise a first slot (111 ) closest to the center of the rotor, a second slot (112) and a third slot (113) which are furthest from the center of the rotor, a fourth slot (114) located between the first slot (111 ) and the second slot (112), and a fifth slot (115) located between the first slot (111 ) and the third slot (113), wherein the second slot (112) and the third slot (113) are symmetric with respect to the axis of symmetry, the fourth slot (114) and the fifth slot (115) are symmetric with respect to the axis of symmetry, and the first slot (111 ) is itself symmetric with respect to the axis of symmetry, wherein the second flux barrier layer (12) comprises three slots, with flux bridges provided between two adjacent slots, wherein the three slots comprise a sixth slot (121 ) closest to the center of the rotor, and a seventh slot (122) and an eighth slot (123) which are remote from the center of the rotor, wherein the seventh slot (122) and the eighth slot (123) are symmetric with respect to the axis of symmetry, the sixth slot (121 ) is itself symmetric with respect to the axis of symmetry, and a distance between the seventh slot (122) and the eighth slot (123) gradually increases in a direction away from the center of the rotor, wherein injection-molded permanent magnets are packed in the fourth slot (114) and the fifth slot (115), and sintered permanent magnets are packed in the seventh slot (122) and the eighth slot (123).

2. The rotor as claimed in claim 1 , wherein no permanent magnets are packed in the second slot (112) and the third slot (113), and no permanent magnets are packed in spaces separating the sintered permanent magnets from edges of the seventh slot (122) and the eighth slot (123) that are remote from the center of the rotor.

3. The rotor as claimed in claim 1 , wherein injection-molded permanent magnets are packed in spaces separating the sintered permanent magnets from edges of the seventh slot (122) and the eighth slot (123) that are close to the center of the rotor.

4. The rotor as claimed in claim 1 , wherein the multiple arc-shaped flux barrier layers further comprise a third arc-shaped flux barrier layer (13), wherein the third arc-shaped flux barrier layer (13) is closer than the second flux barrier layer (12) to the center of the rotor, or the third arc-shaped flux barrier layer (13) is located between the first arc-shaped flux barrier layer (11 ) and the second flux barrier layer (12).

5. The rotor as claimed in claim 4, wherein an opening of the third arc-shaped flux barrier layer (13) faces toward the edge of the rotor, and the third arc-shaped flux barrier layer (13) comprises five slots, with flux bridges provided between two adjacent slots, wherein the five slots comprise a ninth slot (131 ) closest to the center of the rotor, a tenth slot (132) and an eleventh slot (133) which are furthest from the center of the rotor, a twelfth slot (134) located between the ninth slot (131 ) and the tenth slot (132), and a thirteenth slot (135) located between the ninth slot (131 ) and the eleventh slot (133), wherein the tenth slot (132) and the eleventh slot (133) are symmetric with respect to the axis of symmetry, the twelfth slot (134) and the thirteenth slot (135) are symmetric with respect to the axis of symmetry, and the ninth slot (131 ) is itself symmetric with respect to the axis of symmetry, wherein injection-molded permanent magnets are packed in the twelfth slot (134) and the thirteenth slot (135), and no permanent magnets are packed in the tenth slot (132) and the eleventh slot (133).

6. The rotor as claimed in claim 1 , wherein the sintered permanent magnet is made of NdFeB.

7. The rotor as claimed in claim 1 , wherein the injection-molded permanent magnet is formed by mixing particles of a magnetic material and particles of a plastic, the mass ratio of the particles of the magnetic material to the particles of the plastic being adjustable.

8. The rotor as claimed in claim 7, wherein the magnetic material comprises at least one of SmFeN and NdFeB, and the plastic comprises at least one of PA12, PP and PPS.

9. The rotor as claimed in claim 1 , wherein widths of the flux bridges are adjustable.

10. A permanent magnet synchronous motor, characterized in that the permanent magnet synchronous motor comprises a stator on which a winding is provided, and the rotor as claimed in any one of claims 1 - 9.

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