A permanent magnet flat wire drive motor rotor structure

Abstract

The present invention discloses a permanent magnet flat wire drive motor rotor structure, comprising a rotor core, multiple magnetic poles, and non-magnetic material. The multiple magnetic poles are evenly distributed circumferentially around the rotor core, and non-magnetic material is disposed on both sides of each magnetic pole. Each magnetic pole and non-magnetic material are embedded in the rotor core and extend axially along the rotor core. Each magnetic pole is symmetrical along the d-axis and includes multiple permanent magnets. The multiple permanent magnets are arranged in a stepped manner on both sides of the d-axis, and the outer sides of each layer of stepped permanent magnets are arranged in a zigzag shape. The magnetic poles are open outward, and the innermost layers of permanent magnets on both sides of the d-axis contact each other, while the permanent magnets in other layers do not contact each other. The rotor structure of the present invention utilizes the stepped arrangement of multiple permanent magnets to not only improve the utilization rate of the permanent magnets, but also improve the power (torque) density of the motor, meeting the high power density requirements of the permanent magnet flat wire motor. At the same time, due to the improved utilization rate of the permanent magnets, the amount of permanent magnets used is reduced, thereby reducing the cost of the motor.

Description

Technical Field

[0001] The present invention relates to permanent magnet motor technology, and in particular to a permanent magnet flat wire drive motor rotor structure. Background Art

[0002] The trend toward lightweight, highly integrated, and high-voltage powertrains in new energy vehicles is placing new and stringent demands on the power density and efficiency of drive motors. Permanent magnet flat-wire drive motors utilize flat-wire windings. While maintaining the same space, flat-wire motors offer a higher slot fill rate and increased copper usage compared to round-wire motors, generating a stronger magnetic field and increasing the motor's power (torque) density. Furthermore, flat-wire motors have fewer internal slots, increasing the contact area between the flat wires and improving heat dissipation and thermal conductivity. Furthermore, the conductors of flat-wire motors exhibit greater stress and rigidity, resulting in greater armature stiffness and suppressing armature noise. In summary, the advantages of a compact size, high power density, superior acceleration performance, and low noise level make permanent magnet flat-wire drive motors promising for development in the new energy vehicle sector.

[0003] While flat wire motors offer many advantages, they also have some inherent drawbacks, such as significant skin effect and high eddy current losses in the windings during high-speed operation. Furthermore, the complex flat wire processing steps, high equipment precision requirements, and significant processing difficulty are all factors. Therefore, as the performance requirements for permanent magnet flat wire motors continue to increase, optimizing the rotor structure is also necessary, alongside the search for flat wire motor winding design methods. Currently, the "double V" permanent magnet rotor structure is the mainstream rotor design for permanent magnet flat wire drive motors. While this "double V" permanent magnet rotor structure can increase the salient pole ratio and improve the motor's torque output capability, the multi-layer permanent magnet rotor structure has a high magnetic resistance, resulting in reduced permanent magnet utilization, increased motor cost, and limiting the further promotion of the permanent magnet flat wire drive motor industry. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a permanent magnet flat wire drive motor rotor structure for increasing the power density of the permanent magnet flat wire drive motor and improving the utilization rate of the permanent magnet.

[0005] Technical solution: The present invention provides a permanent magnet flat wire drive motor rotor structure, comprising a rotor core, multiple magnetic poles and non-magnetic material. The multiple magnetic poles are evenly distributed circumferentially around the rotor core, and non-magnetic material is arranged on both sides of each magnetic pole. Each magnetic pole and non-magnetic material are embedded in the rotor core and extend axially along the rotor core; each magnetic pole is symmetrical along the d-axis, and each magnetic pole includes multiple permanent magnets, which are arranged in a stepped manner on both sides of the d-axis, and the outer sides of each layer of stepped permanent magnets are arranged in a serrated shape, with the magnetic poles opening outward. The innermost layers of permanent magnets on both sides of the d-axis are in contact with each other, and the other layers of rectangular permanent magnets are not in contact.

[0006] Preferably, the permanent magnets are rectangular permanent magnets. Arranging multiple rectangular permanent magnets in a stepped pattern not only improves permanent magnet utilization, but also increases motor power (torque) density, meeting the high power density requirements of permanent magnet flat wire motors. Furthermore, since permanent magnet utilization is increased and magnet usage is reduced, motor costs are reduced.

[0007] Preferably, the number and size of the permanent magnets are adjusted according to different motors to achieve a structural form that is most beneficial to the motor power density and the amount of permanent magnets used.

[0008] Preferably, the magnetization direction of each permanent magnet is along the d-axis.

[0009] Preferably, the width of the stepped permanent magnets decreases from the innermost layer to the outer layer.

[0010] Preferably, non-magnetic material is provided on both sides of each magnetic pole in contact with the permanent magnet to reduce the leakage magnetic field of the permanent magnet and enhance the air gap magnetic field; the side of the non-magnetic material in contact with the permanent magnet is serrated, and the other side is straight to reduce the process difficulty. The width of the non-magnetic material can be appropriately selected to achieve the purpose of blocking the leakage magnetic field between the permanent magnets; the non-magnetic material on both sides of the same magnetic pole is symmetrical along the d axis.

[0011] Based on the same inventive concept, in another embodiment of the present invention, a permanent magnet flat wire drive motor rotor structure includes a rotor core, multiple magnetic poles and non-magnetic material. The multiple magnetic poles are evenly distributed around the circumference of the rotor core, and non-magnetic material is arranged on both sides of each magnetic pole. Each magnetic pole and non-magnetic material is embedded in the rotor core and extends axially along the rotor core; each magnetic pole is a symmetrical stepped shape opening outward, the axis of symmetry is the d axis, and the outer sides of each layer of steps are arranged in a serrated shape.

[0012] Preferably, the multiple permanent magnets are axially arranged into a multi-segment structure.

[0013] Preferably, the rotor core is axially arranged as a multi-section skew pole structure.

[0014] Preferably, the non-magnetic material is stainless steel, and the non-magnetic material is bonded to the permanent magnets and embedded in the rotor core. The function of the non-magnetic material is to reduce magnetic leakage between the permanent magnets, so that the motor can obtain higher power (torque) density.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant technical effects:

[0016] Compared with the "double V" permanent magnet rotor structure of the mainstream permanent magnet flat wire drive motor, the rotor structure proposed in the present invention utilizes multiple permanent magnets arranged in a stepped manner, which can improve the utilization rate of permanent magnets, reduce the amount of permanent magnets used, and improve the power (torque) density of the motor. At the same time, the non-magnetic material arranged at both ends of each magnetic pole can reduce the leakage flux between permanent magnets, further improve the power (torque) density of the motor, and meet the high power density requirements of the permanent magnet flat wire motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic cross-sectional view of the rotor structure of a permanent magnet flat wire drive motor with 8 rotor poles according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a transverse cross-sectional structure of a rotor core of a permanent magnet flat wire drive motor rotor structure with 8 rotor poles according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the three-dimensional structure of the rotor core of a permanent magnet flat wire drive motor rotor structure with 8 rotor poles according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the three-dimensional structure of the permanent magnet of a rotor structure of a permanent magnet flat wire drive motor with 8 rotor poles according to an embodiment of the present invention;

[0021] Figure 5 Comparison of the magnetic flux paths of a permanent magnet flat wire drive motor with a 48-slot stator and an 8-pole rotor according to an embodiment of the present invention with and without non-magnetic conductive material. (a) shows the magnetic flux path without non-magnetic conductive material, and (b) shows the magnetic flux path with non-magnetic conductive material.

[0022] Figure 6 The characteristics of torque variation with current density for a permanent magnet flat wire drive motor with 48 stator slots and 8 rotor poles respectively using the rotor structure described in the embodiment of the present invention and the "double V" type permanent magnet rotor structure;

[0023] Figure 7 A comparison of the permanent magnet volumes of a permanent magnet flat wire drive motor with a 48-slot stator and an 8-pole rotor using the rotor structure described in the embodiment of the present invention and a "double V" permanent magnet rotor structure;

[0024] In the figure: 1. Rotor core, 2. Permanent magnet, 3. Non-magnetic material, 4. Magnetic pole. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and are not to be construed as limiting the present invention.

[0026] Example 1:

[0027] The rotor structure of a permanent magnet flat wire drive motor of the present invention is as follows: Figures 1 to 4 As shown, it includes a rotor core 1, multiple magnetic poles 4 and non-magnetic material 3; multiple magnetic poles 4 are evenly distributed circumferentially around the rotor core 1, each magnetic pole 4 and non-magnetic material 3 are embedded in the rotor core 1 and extend axially along the rotor core 1; each magnetic pole 4 is an outward-opening axially symmetrical structure composed of multiple permanent magnets 2 arranged in a stepped manner, the symmetry axis is the d-axis, the innermost layers of permanent magnets on both sides of the d-axis are in contact with each other, and the other layers of permanent magnets are not in contact; each permanent magnet 2 is a rectangular structure, and non-magnetic material 3 is provided on both sides of each magnetic pole 4 in contact with the permanent magnet 2 to reduce the leakage magnetic field of the permanent magnet and enhance the air gap magnetic field.

[0028] Figure 5 (a) and (b) are comparisons of the magnetic flux paths of a permanent magnet flat wire drive motor with a stator of 48 slots and a rotor of 8 poles described in an embodiment of the present invention, with and without non-magnetic materials provided on the rotor. Since the rotor core has good magnetic conductivity and small magnetic resistance, the stepped arrangement of the permanent magnets has smaller magnetic resistance than the "double V" permanent magnet structure. The magnetic flux generated by the permanent magnets passes through the core and enters the air gap of the motor in greater amounts. The enhanced magnetic field in the air gap increases the output power (torque) of the motor, thereby improving the utilization rate of the permanent magnets and reducing the amount of permanent magnets used. At the same time, the non-magnetic material provided at both ends of the magnetic pole has a large magnetic resistance. Figure 5 As can be seen in (a) and (b), the non-magnetic material blocks the magnetic flux loop at both ends of the magnetic pole, allowing more magnetic flux to enter the motor air gap along the iron core, further increasing the motor's output power (torque).

[0029] Furthermore, each of the magnetic poles 4 is composed of multiple rectangular permanent magnets 2. The number and size of the rectangular permanent magnets 2 are not limited. The number and size of the rectangular permanent magnets 2 can be appropriately adjusted for different motors to achieve a structural form that is most conducive to the motor power density and permanent magnet usage.

[0030] Furthermore, the plurality of rectangular permanent magnets 2 are sequentially embedded in the rotor core 1 and extend axially along the rotor core 1 .

[0031] Furthermore, the magnetization direction of the plurality of rectangular permanent magnets 2 is along the d-axis direction.

[0032] Furthermore, the multiple rectangular permanent magnets 2 of each magnetic pole 4 are arranged in a stepped manner, in order to improve the utilization rate of the permanent magnets and reduce the amount of permanent magnets used.

[0033] Furthermore, non-magnetic material 3 is provided on both sides of each magnetic pole 4 in contact with the permanent magnet 2. The non-magnetic material 3 can be selected from stainless steel. The non-magnetic material 3 is adhered to the permanent magnet 2 and embedded in the rotor core 1. The function of the non-magnetic material 3 is to reduce the magnetic leakage between the permanent magnets, so that the motor can obtain a higher power (torque) density.

[0034] Furthermore, the rectangular permanent magnets 2 arranged on both sides of the symmetry axis d of each magnetic pole 4 have the same size. The width of the rectangular permanent magnets arranged in a stepped manner decreases from the innermost layer to the outside.

[0035] Furthermore, one side of the structure of the non-magnetic material 3 must fit the structure of the magnetic pole 4, so it is zigzag-shaped, and the other side is straight to reduce the difficulty of the process. The width of the non-magnetic material 3 can be appropriately selected to achieve the purpose of blocking the leakage of magnetic flux between the permanent magnets 2.

[0036] Furthermore, the sizes of the permanent magnet 2 and the non-magnetic material 3 are only examples. Other existing or future possible application types of the sizes of the permanent magnet 2 and the non-magnetic material 3, if applicable to the embodiments of the present invention, should also be included in the scope of protection of the present invention and are included here by reference.

[0037] Figure 6 The torque variation characteristics of a permanent magnet flat wire drive motor with a 48-slot stator and an 8-pole rotor were compared using the rotor structure described in the embodiments of the present invention and a "double-V" permanent magnet rotor structure. The comparison shows that the permanent magnet flat wire drive motor with the rotor structure disclosed in the present invention has a greater electromagnetic torque than the motor with the "double-V" permanent magnet rotor structure. This comparison demonstrates the superiority of the rotor structure disclosed in the present invention in improving motor power (torque) density.

[0038] Figure 7 A comparison of the permanent magnet volumes of a 48-slot stator and 8-pole permanent magnet flat wire drive motor using the rotor structure described in the embodiments of the present invention and a "double-V" permanent magnet rotor structure is shown. The comparison shows that the rotor structure of the permanent magnet flat wire drive motor disclosed in the present invention not only has advantages in improving motor power (torque) density, but also uses less permanent magnets than the "double-V" permanent magnet rotor structure. This comparison fully demonstrates the superiority of the rotor structure disclosed in the present invention in saving permanent magnets and improving permanent magnet utilization.

[0039] Example 2:

[0040] Example 2 mainly describes the differences from Example 1. The implementation methods not specifically described in Example 2 are the same as those in Example 1.

[0041] In Example 1, multiple rectangular permanent magnets 2 are arranged in a stepped manner and embedded in the rotor core 1 in sequence to form a magnetic pole 4. Another implementation method can directly process the permanent magnets 2 into a stepped magnetic pole 4 structure, and then embed the magnetic pole 4 as a whole into the rotor core 1 without being divided into multiple rectangular permanent magnets 2, which can reduce the difficulty of the motor rotor process.

[0042] Furthermore, the plurality of permanent magnets 2 in Example 1 and Example 2 can be divided into multiple sections in the axial direction to reduce eddy current losses of the permanent magnets.

[0043] Furthermore, the rotor core 1 in Example 1 and Example 2 can be divided into multiple sections of skewed pole structures in the axial direction to reduce motor vibration and noise.

[0044] Furthermore, the non-magnetic material 3 in Example 1 and Example 2 can be made of stainless steel or other non-magnetic materials, which can achieve the purpose of blocking magnetic flux leakage between the permanent magnets 2 without increasing the eddy current loss of the rotor.

[0045] In summary, compared with the double V-shaped permanent magnet rotor structure of the mainstream permanent magnet flat wire drive motor, the rotor structure of the present invention can improve the power (torque) density of the permanent magnet flat wire drive motor, reduce the amount of permanent magnets used, and meet the high power (torque) density requirements of the permanent magnet flat wire drive motor.

[0046] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several anticipated improvements and equivalent substitutions can be made without departing from the principles of the present invention. These technical solutions after improvements and equivalent substitutions to the claims of the present invention all fall within the scope of protection of the present invention.

Claims

1. A permanent magnet flat wire drive motor rotor structure, characterized in that: The invention comprises a rotor core (1), a plurality of magnetic poles (4) and a non-magnetic material (3), wherein the plurality of magnetic poles (4) are uniformly distributed around the rotor core (1) in the circumferential direction, and non-magnetic material (3) is provided on both sides of each magnetic pole (4), and each magnetic pole (4) and non-magnetic material (3) are embedded in the rotor core (1) and extend axially along the rotor core (1); each magnetic pole (4) is symmetrical along the d-axis, and each magnetic pole (4) comprises a plurality of permanent magnets (2), and the plurality of permanent magnets (2) are arranged in a stepped manner on both sides of the d-axis, and the width of the stepped permanent magnets decreases from the innermost layer to the outermost layer, and the outer sides of each layer of stepped permanent magnets are arranged in a sawtooth shape, and the magnetic poles (4) are opened outward, and the innermost layers of permanent magnets on both sides of the d-axis are in contact with each other, and the rectangular permanent magnets of other layers outside the innermost layer are not in contact.

2. A permanent magnet flat wire drive motor rotor structure according to claim 1, characterized in that: The permanent magnet (2) is a rectangular permanent magnet.

3. The permanent magnet flat wire drive motor rotor structure according to claim 1, characterized in that: The number and size of permanent magnets are adjusted according to different motors to achieve a structural form that is most conducive to the motor power density and permanent magnet usage.

4. The permanent magnet flat wire drive motor rotor structure according to claim 1, characterized in that: The magnetization direction of each permanent magnet is along the d-axis.

5. The permanent magnet flat wire drive motor rotor structure according to claim 1, characterized in that: Non-magnetic materials are provided on both sides of each magnetic pole in contact with the permanent magnet. The non-magnetic materials are zigzag-shaped on one side and straight-line-shaped on the other side. The non-magnetic materials on both sides of the same magnetic pole are symmetrical along the d axis.

6. The permanent magnet flat wire drive motor rotor structure according to claim 1, characterized in that: The multiple permanent magnets (2) are arranged in a multi-segment structure in the axial direction.

7. The permanent magnet flat wire drive motor rotor structure according to claim 1, characterized in that: The rotor core (1) is axially arranged as a multi-section skew pole structure.

8. The permanent magnet flat wire drive motor rotor structure according to claim 1, characterized in that: The non-magnetic material is stainless steel.

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