A rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive

Abstract

The utility model discloses a kind of rotor structures of unsymmetrical permanent magnet synchronous motor for electric vehicle driving, including rotor, the rotor includes rotor core and several magnetic pole groups embedded in the rotor core, each the magnetic pole group is sequentially arranged along the circumferential spacing of the rotor core;Each the magnetic pole group includes side-by-side arranged first permanent magnet and second permanent magnet, each the first permanent magnet is V-shaped, each second permanent magnet is spoke type, the first permanent magnet and the second permanent magnet in each the magnetic pole group between it is provided with magnetic barrier;In the cross section of rotor, the center line of each the first permanent magnet and the center line between its adjacent two second permanent magnets are provided with offset angle. Compared with prior art, by the difference of offset angle, introduce magnetic field space offset effect, increase motor torque, and combined with the setting of magnetic barrier, thereby synergistically improve torque ripple and cogging torque, reduce torque ripple and cogging torque.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and more specifically to a rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive. Background Technology

[0002] Due to growing concerns about the energy crisis and environmental pollution, electric vehicles (EVs) and hybrid electric vehicles (HEVs) have been extensively researched. As one of the key technologies for EVs and HEVs, the design and performance of the electric motor are crucial. Based on this, various types of motors have been proposed for the market, among which permanent magnet synchronous motors have attracted significant attention due to their high torque density, high power density, and high efficiency.

[0003] The rotor structure of most existing permanent magnet synchronous motors is as follows: Figure 1 As shown, symmetrical V-type or spoke-type structures are used, but they all have the problem of inconsistent current angles between electromagnetic torque and reluctance torque, which limits the maximum combined torque. At the same time, the cogging torque and torque pulsation are large, affecting the smoothness of the permanent magnet synchronous motor and the performance of electric vehicles.

[0004] In view of this, this application has conducted in-depth research on this basis, resulting in this case. Utility Model Content

[0005] The purpose of this invention is to provide a rotor structure for an asymmetric permanent magnet synchronous motor for electric vehicle drive, which can increase motor torque and reduce torque pulsation and cogging torque.

[0006] To achieve the above objectives, the solution of this utility model is: A rotor structure for an asymmetric permanent magnet synchronous motor for electric vehicle drive includes a rotor, which includes a rotor core and a plurality of magnetic pole groups embedded in the rotor core. Each magnetic pole group is arranged sequentially at circumferential intervals along the rotor core. Each magnetic pole group includes a first permanent magnet and a second permanent magnet arranged side by side. Each first permanent magnet is V-shaped and each second permanent magnet is spoke-shaped. A magnetic barrier is provided between the first permanent magnet and the second permanent magnet in each magnetic pole group. The radial center line of each first permanent magnet and the radial center lines between two adjacent second permanent magnets are offset at an angle.

[0007] The arc angle of each of the first permanent magnets is 120°-150°.

[0008] A magnetic isolation bridge is provided between each of the first permanent magnets at the end opposite to the outside of the rotor, and the width of each magnetic isolation bridge is the same.

[0009] Each of the first permanent magnets includes two permanent magnets, both of which are arranged away from each other from the inside out.

[0010] The offset angle is 15°-30°.

[0011] Each of the magnetic barriers is located close to the outer side of the rotor.

[0012] In each group of magnetic poles, the first arc angle is defined as the arc angle between the center of the magnetic barrier and the first permanent magnet. θ ab1 The arc angle between the center of the magnetic barrier and the second permanent magnet is the second arc angle. θ abr The first arc angle and the second arc angle are not equal, and 0.08 ≤ θ ab1 / θ abr ≤0.12.

[0013] The rotor is a rotor body made of several silicon steel sheets, each of which has a thickness of 0.35-0.5 mm.

[0014] The rotor has a plurality of magnetic pole slots, each magnetic pole slot being paired with a magnetic pole group in a one-to-one manner, and each magnetic pole group being embedded in the corresponding magnetic pole slot.

[0015] There are four sets of magnetic poles.

[0016] By adopting the above structure, this utility model has the following beneficial effects: 1. This utility model adopts the setting of offset angle in each group of magnetic poles, that is, the radial center line of the first permanent magnet is offset relative to the radial center lines of the two second permanent magnets, so that the rotor forms an asymmetrical structure. By the difference in offset angle between the first permanent magnet and the second permanent magnet, a magnetic field spatial offset effect is introduced, so that the direction of the main vector of the magnetic field is slightly deflected between the pole pairs. This helps to optimize the coupling of the permanent magnet flux linkage and the armature reaction flux linkage, improve the torque synthesis efficiency, that is, increase the motor torque and improve the overall operating performance of the motor. In addition, combined with the setting of magnetic barriers, a magnetic flux discharge buffer is formed on the surface of the rotor to weaken the coupling path of high-frequency magnetomotive force harmonics, thereby synergistically improving torque pulsation and cogging torque, and reducing torque pulsation and cogging torque.

[0017] 2. The equal width design of the magnetic bridge in this utility model can adjust the local magnetic permeability channel of the rotor and limit the leakage magnetic diffusion, so as to play an important role in weakening the higher harmonic magnetomotive force in magnetic modeling. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the rotor structure in a conventional permanent magnet synchronous motor.

[0019] Figure 2 This is a schematic diagram of the rotor in this utility model.

[0020] Figure 3 This is a diagram showing the angle markings of the rotor in this utility model.

[0021] Figure 4 To adopt Figure 1 Rotor structure and application Figure 2 A comparison diagram of the cogging torque of the rotor structure.

[0022] Figure 5 To adopt Figure 1 Rotor structure and application Figure 2 A comparison of the load torque output curves of the rotor structure.

[0023] In the picture: 100-Rotor; 1-Rotor core; 2-Magnetic pole group; 21-First permanent magnet; 22-Second permanent magnet; 3-Magnetic barrier; 4-Magnetic bridge. Detailed Implementation

[0024] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.

[0025] A rotor structure for an asymmetric permanent magnet synchronous motor used in electric vehicle drive, such as Figure 1 As shown, the permanent magnet synchronous motor includes a motor body (not shown in the figure), which includes a rotor 100 and a stator. The stator is conventionally mounted on the outside of the rotor. The stator structure adopts the stator structure used in existing motors, and an air gap is formed between the stator and the rotor. A rotating shaft (not shown in the figure) is mounted on the rotor 100. The mounting structure between the rotating shaft (not shown in the figure) and the rotor 100, as well as the mounting structure between the rotor and the stator, are all conventional mounting structures used in existing motors, and therefore will not be described in detail.

[0026] For ease of description, the side where the axis of rotor 100 is located is called the inner side, and the side opposite to it is called the outer side.

[0027] like Figure 2As shown, in this utility model, the rotor 100 is an asymmetrically arranged rotor. Specifically, the rotor 100 includes a rotor core 1 and several magnetic pole groups 2. Each magnetic pole group 2 is embedded in the rotor core 1, and the magnetic pole groups 2 are arranged at intervals along the circumference of the rotor core. Each magnetic pole group 2 includes a first permanent magnet 21 and a second permanent magnet 22 arranged side-by-side. The first permanent magnet 21 in each magnetic pole group 2 is V-shaped, and the second permanent magnet 22 in each magnetic pole group 2 is spoke-shaped. Furthermore, the first permanent magnet 21 in each magnetic pole group 2... A magnetic barrier 3 is provided between the first permanent magnet 21 and the second permanent magnet 22. This magnetic barrier 3 is used to further control the spatial distribution of the air gap permeability. In the cross-section of the rotor 100, the centerline of each first permanent magnet 21 has an offset angle with the centerlines of its two adjacent second permanent magnets 22. That is, the radial centerline of each first permanent magnet 21 has an offset angle with the radial centerlines of its two adjacent second permanent magnets 22. Here, the radial centerline refers to a straight line extending radially along the rotor 100. The offset angle is denoted as . θ v By using this offset angle, the rotor 100 forms an asymmetrical structure, which enables fine adjustment of the magnetic flux density and torque output direction. This introduces a magnetic field offset effect into the overall rotor structure, improves the vector superposition efficiency of the permanent magnet magnetomotive force and the armature reaction magnetic field, thereby increasing the average torque of the motor and reducing torque pulsation.

[0028] Specifically, the structures of each of the above-mentioned magnetic pole groups 2 are the same. Therefore, we will take one of the magnetic pole groups 2 as an example for explanation. The first permanent magnet 21 in the magnetic pole group 2 includes two permanent magnets. The two permanent magnets are arranged away from each other from the inside to the outside, thus forming a V-shape. The second permanent magnets 22 in each magnetic pole group 2 are radially distributed with the axis of the rotor 100 as the base point, so that the first permanent magnet 21 and the second permanent magnet 22 together form a 1.5-layer composite magnet structure, making the rotor 100 an asymmetrical structure.

[0029] In this way, since each of the second permanent magnets 22 is respectively set in the magnetic pole center area of ​​the rotor 100, and the magnetization direction of each second permanent magnet 22 is radially outward, in conjunction with each of the first permanent magnets 21, a superposition of magnetomotive forces in parallel along the radial and oblique directions can be formed, which effectively increases the d-axis flux linkage and improves the torque output capability of the permanent magnet synchronous motor. At the same time, its distributed form enhances the q-axis reluctance difference, improves the reluctance torque, and realizes the efficient coupling of permanent magnet torque and reluctance torque. Here, oblique direction refers to the extension direction of the two permanent magnets in the first permanent magnet 21.

[0030] As a preferred option, such as Figure 3 As shown, the arc angle of each of the first permanent magnets 21 is 120°-150°. In this embodiment, this arc angle is denoted as... θ apIt should be noted that the arc angle of the first permanent magnet 21 can be set according to the actual parameters of the motor, such as the motor diameter, number of poles and speed.

[0031] As a preferred option, such as Figure 3 As shown, the offset angle in each group of magnetic poles is 15°-30°. In this embodiment, this offset angle is denoted as... θ v It should be noted that the offset angle can be set according to the actual parameters of the motor, such as motor diameter, number of poles, and speed.

[0032] Furthermore, each of the first permanent magnets 21 has a magnetic isolation bridge 4 at the inner end between the two permanent magnets, and the width of each magnetic isolation bridge 4 is the same, such as... Figure 3 As shown, this width is denoted as b inv The width here refers to the direction from one permanent magnet to another in the same first permanent magnet 21 within the cross section of rotor 1; in this way, the local magnetic permeability channel of rotor 1 is adjusted, leakage magnetic diffusion is limited, and higher harmonic magnetomotive force is weakened.

[0033] To elaborate further, such as Figure 2 As shown, each magnetic barrier 3 is located near the outer edge of the rotor 100, i.e., near the air gap. The magnetic barrier 3 can be a through slot formed on the rotor core 1, or it can be a spatial channel filled with a conventional low-permeability material. In this embodiment, a through slot formed on the rotor core 1 is used as an example for illustration. Preferably, in each group of magnetic poles 2, such as... Figure 3 As shown, the first arc angle is defined as the arc angle between the center of the magnetic barrier 3 and the outer end of the adjacent first permanent magnet 21. This first arc angle is denoted as . θ ab1 The second arc angle is defined as the arc angle between the center of the magnetic barrier 3 and the radial centerline of its adjacent second permanent magnet 22. This second arc angle is denoted as... θ abr The first and second arc angles are not equal, and the position of the magnetic barrier 3 is determined by the double arc angle positioning, preferably 0.08≤ θ ab1 / θ abr ≤0.12 to reduce harmonics.

[0034] Furthermore, the rotor 100 mentioned above is a rotor body made of several silicon steel sheets. In this embodiment, the rotor body is made of silicon steel sheets by a stacking process, which is a conventional operation. The silicon steel sheets are conventional high-strength, low-iron-loss silicon steel sheets. Preferably, the thickness of each silicon steel sheet is 0.35-0.5mm, and the thickness of each silicon steel sheet is set according to the actual situation of the motor, and is not limited here.

[0035] Furthermore, the rotor 100 is provided with a number of magnetic pole slots, and each magnetic pole slot is matched one-to-one with each magnetic pole group 2. That is, each magnetic pole slot is matched with the first permanent magnet 21 and the second permanent magnet 22, so that the first permanent magnet 21 and the second permanent magnet 22 are respectively embedded in each magnetic pole slot.

[0036] It should be noted that the installation of the aforementioned permanent magnets and the setting of magnetic barriers 3 and magnetic isolation bridges 4 are all conventional installation and setting methods in the existing motor field, so they will not be described in detail here.

[0037] In this embodiment, four magnetic pole groups 2 are used as an example for illustration. The number of magnetic pole groups 2 is set according to the actual situation and requirements.

[0038] To elaborate further, such as Figure 4 As shown, the present invention and the traditional symmetrical V-type rotor structure were compared in terms of cogging torque through simulation. The results show that the symmetrical V-type rotor structure has a higher cogging torque amplitude, while the cogging torque amplitude of the rotor structure of the present invention is significantly reduced.

[0039] To elaborate further, such as Figure 5 As shown, the rotor structure provided by this utility model achieves a higher average torque (an increase of about 8%) under the same permanent magnet volume and control strategy, while keeping the peak and valley values ​​of torque fluctuation within a low range, thus meeting the comprehensive requirements of electric drive systems for vibration, noise and output stability.

[0040] This invention discloses a rotor structure for an asymmetric permanent magnet synchronous motor for electric vehicle drive. In each group of magnetic poles, a 1.5-layer magnet structure is introduced, with optimized arrangement of magnetic barriers and asymmetric magnetic pole structures. This not only improves the average torque output capability but also effectively reduces cogging torque and higher-order torque harmonics. Furthermore, while maintaining existing motor manufacturing processes and stator structures, it possesses significant advantages such as compact structure, flexible design, and ease of mass production. It is particularly suitable for the comprehensive requirements of high efficiency, low noise, and high responsiveness in the field of new energy vehicle drive motors.

[0041] The above description is only a preferred embodiment of this invention. All equivalent changes and modifications made within the scope of the claims of this utility model shall fall within the scope of the claims of this utility model.

Claims

1. A rotor structure for an asymmetric permanent magnet synchronous motor for driving electric vehicles, comprising a rotor, the rotor including a rotor core and a plurality of magnetic pole groups embedded in the rotor core, the magnetic pole groups being arranged sequentially at circumferential intervals along the rotor core; characterized in that: Each of the magnetic pole groups includes a first permanent magnet and a second permanent magnet arranged side by side. Each first permanent magnet is V-shaped and each second permanent magnet is spoke-shaped. A magnetic barrier is provided between the first permanent magnet and the second permanent magnet in each magnetic pole group. The radial center line of each first permanent magnet and the radial center line between the two adjacent second permanent magnets are offset at an angle.

2. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1, characterized in that: The arc angle of each of the first permanent magnets is 120°-150°.

3. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1 or 2, characterized in that: A magnetic isolation bridge is provided between each of the first permanent magnets at the end opposite to the outside of the rotor, and the width of each magnetic isolation bridge is the same.

4. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1 or 2, characterized in that: Each of the first permanent magnets includes two permanent magnets, both of which are arranged away from each other from the inside out.

5. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1, characterized in that: The offset angle is 15°-30°.

6. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1, characterized in that: Each of the magnetic barriers is located close to the outer side of the rotor.

7. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1, characterized in that: In each group of magnetic poles, the first arc angle is defined as the arc angle between the center of the magnetic barrier and the first permanent magnet. θ ab1 The arc angle between the center of the magnetic barrier and the second permanent magnet is the second arc angle. θ abr The first arc angle and the second arc angle are not equal, and 0.08 ≤ θ ab1 / θ abr ≤0.

12.

8. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1, 2, 5, 6 or 7, characterized in that: The rotor is a rotor body made of several silicon steel sheets, each of which has a thickness of 0.35-0.5 mm.

9. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 8, characterized in that: The rotor has a plurality of magnetic pole slots, each magnetic pole slot being paired with a magnetic pole group in a one-to-one manner, and each magnetic pole group being embedded in the corresponding magnetic pole slot.

10. The rotor structure of an asymmetric permanent magnet synchronous motor for electric vehicle drive according to claim 1, 2, 5, 6 or 7, characterized in that: There are four sets of magnetic poles.

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