Rotor and permanent magnet synchronous motor having the same

Abstract

The application discloses a rotor and a permanent magnet synchronous motor with the same. In the application, each magnetic barrier structure of the rotor comprises a first arc-shaped magnetic barrier layer closest to the edge of the rotor and a second magnetic barrier layer closer to the center of the rotor than the first arc-shaped magnetic barrier layer, the first arc-shaped magnetic barrier layer is provided with injection molded permanent magnets, the injection molded permanent magnets are lower in price than sintered permanent magnets, thereby reducing the cost, although the magnetic performance of the injection molded permanent magnets is weaker, however, the arc-shaped magnetic barrier layer design helps to make full use of the reluctance torque of the motor, thereby making up for the decline in the magnetic performance to a certain extent, in addition, the second magnetic barrier layer is provided with sintered permanent magnets with stronger magnetic performance, thereby ensuring that the rotor has sufficient magnetic performance to realize the desired motor performance.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically, to a rotor and a permanent magnet synchronous motor having the rotor. Background Technology

[0002] With the development of new energy vehicles, the performance requirements for drive motors are becoming increasingly stringent. Permanent magnet synchronous motors, with their advantages of lower cost and higher reluctance torque utilization, have gradually gained attention from automobile manufacturers.

[0003] A permanent magnet synchronous motor includes a stator and a rotor. Windings are disposed on the stator, and sintered permanent magnets (i.e., magnetic steel) made of rare-earth materials (e.g., NdFeB) are disposed on the rotor. The sintered permanent magnets are generally cuboid in shape. Correspondingly, slots are formed on the rotor. The sintered permanent magnets are inserted into these slots.

[0004] However, because sintered permanent magnets are rectangular in shape, they cannot fully utilize the reluctance torque of the motor, requiring more sintered permanent magnets to provide permanent magnet torque. In other words, to achieve the same output performance, a permanent magnet synchronous motor requires more sintered permanent magnets than theoretically possible, resulting in higher costs. Furthermore, due to the strong magnetic field near the stator windings, the permanent magnets near the rotor edge (i.e., closest to the stator windings) are at risk of demagnetization. Summary of the Invention

[0005] The starting point of this invention is to provide a rotor and a permanent magnet synchronous motor having the rotor, thereby solving the above-mentioned problems existing in the prior art.

[0006] According to a first aspect of the invention, a rotor is provided having an even number of magnetic barrier structures arranged circumferentially along the rotor, each magnetic barrier structure comprising a plurality of magnetic barrier layers, the plurality of magnetic barrier layers of each magnetic barrier structure having the same axis of symmetry.

[0007] The plurality of magnetic barrier layers include a first arc-shaped magnetic barrier layer closest to the edge of the rotor and a second magnetic barrier layer closer to the center of the rotor than the first arc-shaped magnetic barrier layer.

[0008] The opening of the first arc-shaped magnetic barrier layer faces the edge of the rotor. The first arc-shaped magnetic barrier layer includes five slots, with magnetic bridges between adjacent slots. The five slots include a first slot closest to the center of the rotor, second and third slots furthest from the center of the rotor, a fourth slot between the first and second slots, and a fifth slot between the first and third slots. The second and third slots are symmetrical about the axis of symmetry, as are the fourth and fifth slots. The first slot itself is symmetrical about the axis of symmetry.

[0009] The second magnetic barrier layer includes three slots, with magnetic bridges between adjacent slots. The three slots include a sixth slot closest to the rotor's center, and a seventh and eighth slots furthest from the rotor's center. The seventh and eighth slots are symmetrical about the axis of symmetry, and the sixth slot itself is symmetrical about the axis of symmetry. The distance between the seventh and eighth slots gradually increases in the direction away from the rotor's center.

[0010] The fourth and fifth slots are filled with injection-molded permanent magnets, and the seventh and eighth slots are filled with sintered permanent magnets.

[0011] Optionally, the second and third slots are not filled with permanent magnets, and the space between the edge of the seventh and eighth slots away from the center of the rotor and the sintered permanent magnets is not filled with permanent magnets.

[0012] Optionally, the space between the edge of the seventh and eighth slots near the center of the rotor and the sintered permanent magnet is filled with injection-molded permanent magnets.

[0013] Optionally, the plurality of arc-shaped magnetic barrier layers further includes a third arc-shaped magnetic barrier layer, wherein the third arc-shaped magnetic barrier layer is closer to the center of the rotor than the second magnetic barrier layer, or the third arc-shaped magnetic barrier layer is located between the first arc-shaped magnetic barrier layer and the second magnetic barrier layer.

[0014] Optionally, the opening of the third arc-shaped magnetic barrier layer faces the edge of the rotor. The third arc-shaped magnetic barrier layer includes five slots, with magnetic bridges between adjacent slots. The five slots include a ninth slot closest to the center of the rotor, tenth and eleventh slots furthest from the center of the rotor, a twelfth slot between the ninth and tenth slots, and a thirteenth slot between the ninth and eleventh slots. The tenth and eleventh slots are symmetrical about the axis of symmetry, the twelfth and thirteenth slots are symmetrical about the axis of symmetry, and the ninth slot itself is symmetrical about the axis of symmetry. The twelfth and thirteenth slots are filled with injection-molded permanent magnets, while the tenth and eleventh slots are not filled with permanent magnets.

[0015] Optionally, the sintered permanent magnet is made of NdFeB.

[0016] Optionally, the injection-molded permanent magnet is composed of a mixture of magnetic material particles and plastic particles, and the mass ratio of the magnetic material particles to the plastic particles can be adjusted.

[0017] Optionally, the magnetic material includes at least one of the following: SmFeN and NdFeB, and the plastic includes at least one of the following: PA12, PP and PPS.

[0018] Optionally, the width of each magnetic bridge can be adjusted.

[0019] According to a second aspect of the present invention, a permanent magnet synchronous motor is provided, the permanent magnet synchronous motor comprising a stator and a rotor according to a first aspect of the present invention, wherein the stator is provided with windings.

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

[0021] In this invention, each magnetic barrier structure of the rotor includes a first arc-shaped magnetic barrier layer closest to the edge of the rotor and a second magnetic barrier layer closer to the center of the rotor than the first arc-shaped magnetic barrier layer. The first arc-shaped magnetic barrier layer contains injection-molded permanent magnets, which are cheaper than sintered permanent magnets, thus reducing costs. Although the magnetic properties of injection-molded permanent magnets are weaker, the arc-shaped magnetic barrier layer design helps to fully utilize the reluctance torque of the motor, thereby compensating for the decrease in magnetic properties to some extent. In addition, the second magnetic barrier layer contains sintered permanent magnets with stronger magnetic properties, thereby ensuring that the rotor has sufficient magnetic properties to achieve the desired motor performance.

[0022] In this invention, the positions near the edge of the rotor (i.e., the second and third slots of the first arc-shaped magnetic barrier layer furthest from the center of the rotor, and the space between the edges of the seventh and eighth slots of the second magnetic barrier layer furthest from the center of the rotor and the sintered permanent magnets) can be left unfilled with permanent magnets, so that there is a certain distance between the permanent magnets and the stator windings, thereby reducing the risk of permanent magnet demagnetization.

[0023] In this invention, the space between the edge of the seventh and eighth slots of the second magnetic barrier layer near the center of the rotor and the sintered permanent magnet can be filled with injection-molded permanent magnets, thereby further enhancing the magnetic properties of the rotor.

[0024] In this invention, the rotor may also include a third arc-shaped magnetic barrier layer, thereby further enhancing the magnetic properties of the rotor.

[0025] In this invention, the injection-molded permanent magnet is made of a mixture of magnetic material particles and plastic particles, and the mass ratio of magnetic material particles to plastic particles can be adjusted, thereby allowing the physical and magnetic properties of the injection-molded permanent magnet to be adjusted according to actual needs.

[0026] In this invention, the magnetic material may include at least one of SmFeN and NdFeB, and the plastic may be selected from at least one of PA12 (polydodecanoic acid), PP (polypropylene), and PPS (polyphenylene sulfide), thereby enabling the desired motor performance to be obtained while taking into account both cost and operating environment.

[0027] In this invention, the width of each magnetic bridge can be adjusted, thereby allowing the motor performance to be adjusted according to actual needs. Attached Figure Description

[0028] Other details and advantages of the invention will become apparent from the detailed description provided below. It should be understood that the following drawings are merely schematic and not drawn to scale, and therefore should not be considered as limiting the scope of this application. The following detailed description will refer to the drawings, in which:

[0029] Figure 1 The rotor of a permanent magnet synchronous motor according to a first specific embodiment of the present invention is shown.

[0030] Figure 2 A portion of the rotor of a permanent magnet synchronous motor according to a first specific embodiment of the present invention is shown.

[0031] Figure 3 A portion of the rotor of a permanent magnet synchronous motor according to a second specific embodiment of the present invention is shown. Detailed Implementation

[0032] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the invention. However, it will be apparent to those skilled in the art that implementation of the invention may not include some of these specific details. Furthermore, it should be understood that the invention is not limited to the specific embodiments described. Rather, the invention can be conceived to be practiced with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are illustrative only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0033] Figure 1 The rotor of a permanent magnet synchronous motor according to a specific embodiment of the present invention is shown.

[0034] Figure 2 A portion of the rotor of a permanent magnet synchronous motor according to a first specific embodiment of the present invention is shown.

[0035] like Figure 1 and Figure 2 As shown, the rotor can be formed by stacking silicon steel sheets, with through-holes punched into the silicon steel sheets. The rotor has an even number of magnetic barrier structures 1 arranged circumferentially along the rotor, each magnetic barrier structure comprising multiple magnetic barrier layers, and the multiple magnetic barrier layers of each magnetic barrier structure having the same axis of symmetry. The axis of symmetry preferably extends along the diameter direction of the rotor.

[0036] Continue as Figure 1 and Figure 2As shown, the multiple magnetic barrier layers include a first arc-shaped magnetic barrier layer 11 closest to the edge of the rotor and a second magnetic barrier layer 12 closer to the center of the rotor than the first arc-shaped magnetic barrier layer 11.

[0037] The opening of the first arc-shaped magnetic barrier layer 11 faces the edge of the rotor. The first arc-shaped magnetic barrier layer 11 includes five slots 111, 112, 113, 114, and 115, with magnetic bridges disposed between adjacent slots. The five slots include the first slot 111 closest to the center of the rotor, the second slot 112 and the third slot 113 furthest from the center of the rotor, the fourth slot 114 located between the first slot 111 and the second slot 112, and the fifth slot 115 located between the first slot 111 and the third slot 113. The second slot 112 and the third slot 113 are symmetrical about an axis of symmetry, the fourth slot 114 and the fifth slot 115 are symmetrical about an axis of symmetry, and the first slot 111 itself is symmetrical about an axis of symmetry.

[0038] The second magnetic barrier layer 12 includes three slots, with magnetic bridges between adjacent slots. The three slots include a sixth slot 121 closest to the center of the rotor, and a seventh slot 122 and an eighth slot 123 farther from the center of the rotor. The seventh slot 122 and the eighth slot 123 are symmetrical about an axis of symmetry, and the sixth slot 121 itself is symmetrical about an axis of symmetry. The distance between the seventh slot 122 and the eighth slot 123 gradually increases in the direction away from the center of the rotor, so that in the cross-section of the rotor, the seventh slot 122 and the eighth slot 123 form openings that gradually increase towards the edge of the rotor.

[0039] The fourth slot 114 and the fifth slot 115 are filled with injection-molded permanent magnets (the black parts in the figure), and the seventh slot 122 and the eighth slot 123 are filled with sintered permanent magnets (the red parts in the figure).

[0040] Because injection-molded permanent magnets are cheaper than sintered permanent magnets, costs are reduced. Although the magnetic properties of injection-molded permanent magnets are weaker, the first magnetic barrier layer 11 is designed in an arc shape to help fully utilize the reluctance torque of the motor, thereby compensating for the decrease in magnetic properties to some extent. In addition, the second magnetic barrier layer 12 contains sintered permanent magnets with stronger magnetic properties, thereby ensuring that the rotor has sufficient magnetic properties to achieve the desired motor performance.

[0041] Continue as Figure 1 and Figure 2 As shown, the second slot 112 and the third slot 113 are not filled with permanent magnets, and the spaces between the edges of the seventh slot 122 and the eighth slot 123, which are far from the center of the rotor, and the sintered permanent magnets are also not filled with permanent magnets. This creates a certain distance between the permanent magnets and the stator windings, thereby reducing the risk of permanent magnet demagnetization.

[0042] Continue as Figure 1 and Figure 2As shown, the spaces between the edges of the seventh slot 122 and the eighth slot 123 near the center of the rotor and the sintered permanent magnets are filled with injection-molded permanent magnets. This further enhances the magnetic properties of the rotor.

[0043] Continue as Figure 1 and Figure 2 As shown, the rotor may further include a third arc-shaped magnetic barrier layer 13 closer to the center of the rotor than the second magnetic barrier layer 12, thereby further enhancing the magnetic properties of the rotor. The opening of the third arc-shaped magnetic barrier layer 13 faces the edge of the rotor, and the third arc-shaped magnetic barrier layer 13 includes five slots, with magnetic bridges arranged between adjacent slots. The five slots include the ninth slot 131 closest to the center of the rotor, the tenth slot 132 and the eleventh slot 133 furthest from the center of the rotor, the twelfth slot 134 located between the ninth slot 131 and the tenth slot 132, and the thirteenth slot 135 located between the ninth slot 131 and the eleventh slot 133. The tenth slot 132 and the eleventh slot 133 are symmetrical about the axis of symmetry, the twelfth slot 134 and the thirteenth slot 135 are symmetrical about the axis of symmetry, and the ninth slot 131 itself is symmetrical about the axis of symmetry. The twelfth slot 134 and the thirteenth slot 135 are filled with injection-molded permanent magnets (the black parts in the figure), while the tenth slot 132 and the eleventh slot 133 are not filled with permanent magnets.

[0044] Continue as Figure 1 and Figure 2 As shown, the first slot 111, the sixth slot 121, and the ninth slot 131 are not filled with permanent magnets. However, depending on actual needs, the first slot 111, the sixth slot 121, and the ninth slot 131 can also be filled with permanent magnets, and these variations do not exceed the protection scope of this invention.

[0045] Although Figure 1 and Figure 2 In the first specific embodiment of the invention shown, the third arc-shaped magnetic barrier layer 13 is closer to the center of the rotor than the second magnetic barrier layer 12. However, those skilled in the art will understand that the third arc-shaped magnetic barrier layer 13 can also be disposed in other suitable locations, and these variations do not exceed the scope of protection of the present invention. For example, Figure 3 This describes a portion of the rotor of a permanent magnet synchronous motor according to a second embodiment of the present invention. For example... Figure 3 As shown, the third arc-shaped magnetic barrier layer 13 can be located between the first arc-shaped magnetic barrier layer 11 and the second magnetic barrier layer 12.

[0046] In this invention, the sintered permanent magnet can be sintered from any suitable material, and these variations do not exceed the scope of protection of this invention. Preferably, the sintered permanent magnet is made of rare earth materials with stronger magnetic properties, such as NdFeB.

[0047] In this invention, the magnetic material can be composed of a mixture of magnetic material particles and plastic particles. The mass ratio of magnetic material particles to plastic particles can be adjusted to achieve different physical and magnetic properties. Any suitable magnetic material can be used, such as SmFeN and NdFeB. SmFeN, in particular, has a lower price, which further reduces the cost of the permanent magnet synchronous motor. Additionally, any suitable plastic material can be used to adapt to different motor operating environments; for example, the plastic material can be PA12, PP, and PPS.

[0048] In this invention, the width of each magnetic bridge can be adjusted, thereby enabling the motor performance to be adjusted according to actual needs.

[0049] In this invention, the specific number of magnetic barrier structures 1 arranged circumferentially along the rotor can be set according to actual needs (e.g., the size and design performance of the motor), for example, Figure 1 The diagram shows eight magnetic barrier structures 1 evenly distributed along the circumference of the rotor. The number of magnetic barrier structures 1 can be greater than or less than eight, and their number n can satisfy the formula: n = 2p, where p is a positive integer. These variations do not exceed the protection scope of this invention.

[0050] In this invention, the specific shape of the arc-shaped magnetic barrier layer can be set according to actual needs (such as the size and design performance of the motor), such as hyperbola, arc, parabola, etc., and these variations do not exceed the protection scope of this invention.

[0051] In this invention, the specific number of arc-shaped magnetic barrier layers in each magnetic barrier structure can be set according to actual needs, for example... Figures 1 to 3 Each magnetic barrier structure shown includes three magnetic barrier layers; however, the number of magnetic barrier layers can be greater than or less than three, for example, two or four, as long as the rotor includes the first arc-shaped magnetic barrier layer and the second magnetic barrier layer of the present invention. These variations do not exceed the protection scope of the present invention. Preferably, the rotor includes... Figures 1 to 3 The three magnetic barrier layers shown are designed to achieve better performance and mechanical properties.

[0052] Compared with the prior art, the rotor of the embodiments of the present invention and the permanent magnet synchronous motor having the rotor have at least the following advantages:

[0053] In this invention, each magnetic barrier structure of the rotor includes a first arc-shaped magnetic barrier layer closest to the edge of the rotor and a second magnetic barrier layer closer to the center of the rotor than the first arc-shaped magnetic barrier layer. The first arc-shaped magnetic barrier layer contains injection-molded permanent magnets, which are cheaper than sintered permanent magnets, thus reducing costs. Although the magnetic properties of injection-molded permanent magnets are weaker, the arc-shaped magnetic barrier layer design helps to fully utilize the reluctance torque of the motor, thereby compensating for the decrease in magnetic properties to some extent. In addition, the second magnetic barrier layer contains sintered permanent magnets with stronger magnetic properties, thereby ensuring that the rotor has sufficient magnetic properties to achieve the desired motor performance.

[0054] In this invention, the positions near the edge of the rotor (i.e., the second and third slots of the first arc-shaped magnetic barrier layer furthest from the center of the rotor, and the space between the edges of the seventh and eighth slots of the second magnetic barrier layer furthest from the center of the rotor and the sintered permanent magnets) can be left unfilled with permanent magnets, so that there is a certain distance between the permanent magnets and the stator windings, thereby reducing the risk of permanent magnet demagnetization.

[0055] In this invention, the space between the edge of the seventh and eighth slots of the second magnetic barrier layer near the center of the rotor and the sintered permanent magnet can be filled with injection-molded permanent magnets, thereby further enhancing the magnetic properties of the rotor.

[0056] In this invention, the rotor may also include a third arc-shaped magnetic barrier layer, thereby further enhancing the magnetic properties of the rotor.

[0057] In this invention, the injection-molded permanent magnet is made of a mixture of magnetic material particles and plastic particles, and the mass ratio of magnetic material particles to plastic particles can be adjusted, thereby allowing the physical and magnetic properties of the injection-molded permanent magnet to be adjusted according to actual needs.

[0058] In this invention, the magnetic material may include at least one of SmFeN and NdFeB, and the plastic may be selected from at least one of PA12, PP or PPS, thereby enabling the desired motor performance to be obtained while taking into account both cost and operating environment.

[0059] In this invention, the width of each magnetic bridge can be adjusted, thereby allowing the motor performance to be adjusted according to actual needs.

[0060] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any modifications and alterations made by those skilled in the art without departing from the spirit and scope of the invention should be included within the scope of protection of the invention. Therefore, the scope of protection of the invention should be determined by the scope defined in the claims.

Claims

1. A rotor, characterized in that, The rotor has an even number of magnetic barrier structures (1) arranged circumferentially along the rotor, each magnetic barrier structure comprising multiple magnetic barrier layers, the multiple magnetic barrier layers of each magnetic barrier structure having the same axis of symmetry. The plurality of magnetic barrier layers include a first arc-shaped magnetic barrier layer (11) closest to the edge of the rotor and a second magnetic barrier layer (12) closer to the center of the rotor than the first arc-shaped magnetic barrier layer (11). The opening of the first arc-shaped magnetic barrier layer (11) faces the edge of the rotor. The first arc-shaped magnetic barrier layer (11) includes five slots, with magnetic bridges between adjacent slots. The five slots include a first slot (111) closest to the center of the rotor, a second slot (112) and a third slot (113) furthest from the center of the rotor, a fourth slot (114) between the first slot (111) and the second slot (112), and a fifth slot (115) between the first slot (111) and the third slot (113). The second slot (112) and the third slot (113) are symmetrical about the axis of symmetry, the fourth slot (114) and the fifth slot (115) are symmetrical about the axis of symmetry, and the first slot (111) itself is symmetrical about the axis of symmetry. The second magnetic barrier layer (12) includes three slots, with magnetic bridges between adjacent slots. The three slots include a sixth slot (121) closest to the center of the rotor, and a seventh slot (122) and an eighth slot (123) farther from the center of the rotor. The seventh slot (122) and the eighth slot (123) are symmetrical about the axis of symmetry, and the sixth slot (121) itself is symmetrical about the axis of symmetry. The distance between the seventh slot (122) and the eighth slot (123) gradually increases in the direction away from the center of the rotor. The fourth groove (114) and the fifth groove (115) are filled with injection-molded permanent magnets, and the seventh groove (122) and the eighth groove (123) are filled with sintered permanent magnets.

2. The rotor according to claim 1, wherein, The second groove (112) and the third groove (113) are not filled with permanent magnets, and the space between the edge of the seventh groove (122) and the eighth groove (123) away from the center of the rotor and the sintered permanent magnets is not filled with permanent magnets.

3. The rotor according to claim 1, wherein, The space between the edge of the seventh slot (122) and the eighth slot (123) near the center of the rotor and the sintered permanent magnet is filled with injection-molded permanent magnets.

4. The rotor according to claim 1, wherein, The plurality of arc-shaped magnetic barrier layers also include a third arc-shaped magnetic barrier layer (13), wherein the third arc-shaped magnetic barrier layer (13) is closer to the center of the rotor than the second magnetic barrier layer (12), or the third arc-shaped magnetic barrier layer (13) is located between the first arc-shaped magnetic barrier layer (11) and the second magnetic barrier layer (12).

5. The rotor according to claim 4, wherein, The opening of the third arc-shaped magnetic barrier layer (13) faces the edge of the rotor. The third arc-shaped magnetic barrier layer (13) includes five slots, with magnetic bridges between adjacent slots. The five slots include the ninth slot (131) closest to the center of the rotor, the tenth slot (132) and the eleventh slot (133) furthest from the center of the rotor, the twelfth slot (134) located between the ninth slot (131) and the tenth slot (132), and the slot located between the ninth slot (131) and the eleventh slot (133). The thirteenth groove (135) between the tenth groove (132) and the eleventh groove (133) are symmetrical about the axis of symmetry, the twelfth groove (134) and the thirteenth groove (135) are symmetrical about the axis of symmetry, the ninth groove (131) itself is symmetrical about the axis of symmetry, wherein the twelfth groove (134) and the thirteenth groove (135) are filled with injection-molded permanent magnets, and the tenth groove (132) and the eleventh groove (133) are not filled with permanent magnets.

6. The rotor according to claim 1, wherein, The sintered permanent magnet is made of NdFeB.

7. The rotor according to claim 1, wherein, The injection-molded permanent magnet is made of a mixture of magnetic material particles and plastic particles, and the mass ratio of magnetic material particles to plastic particles can be adjusted.

8. The rotor according to claim 7, wherein, The magnetic material includes at least one of the following: SmFeN and NdFeB, and the plastic includes at least one of the following: PA12, PP and PPS.

9. The rotor according to claim 1, wherein, The width of each magnetic bridge can be adjusted.

10. A permanent magnet synchronous motor, characterized in that, The permanent magnet synchronous motor includes a stator and a rotor according to any one of claims 1 to 9, wherein the stator is provided with windings.

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