Rotor, electric machine and permanent magnet synchronous reluctance electric machine

Abstract

The application provides a rotor, a motor and a permanent magnet synchronous reluctance motor. The rotor comprises a magnetic steel and a rotor core. The magnetic steel comprises a first magnetic steel and a second magnetic steel. The first magnetic steel is a rare earth magnetic steel, and the second magnetic steel is a ferrite magnetic steel. The rotor core forms a plurality of magnetic poles arranged along the circumferential direction thereof. Each magnetic pole is formed with a first magnetic steel slot group, a second magnetic steel slot group and a third magnetic steel slot group arranged along the radial direction of the rotor core in sequence from outside to inside. The first magnetic steel slot group is provided with a first magnetic steel in the first magnetic steel slot. The second magnetic steel slot group is provided with a second magnetic steel in the second magnetic steel slot. The third magnetic steel slot group is provided with a third magnetic steel in the third magnetic steel slot. The advantages of the two kinds of magnetic steels are combined, the waveform of the air gap magnetic density is adjusted, the torque ripple and the harmonic content are effectively reduced, the reluctance torque component is increased, the demagnetization resistance of the motor is improved, the magnetic flux leakage is effectively reduced, the utilization rate of the magnetic steel is improved, the harmonic loss of the motor is reduced, and the problem of power drop of the reluctance motor under high speed working condition is solved.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, and particularly relates to a rotor, a motor and a permanent magnet synchronous reluctance motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in pure electric and hybrid new energy vehicles due to their advantages such as high torque density, high efficiency, good steady-state performance, and high reliability. Existing PMSMs are generally embedded rare-earth permanent magnet motors. Since rare-earth permanent magnet materials are scarce and expensive, effectively utilizing permanent magnet materials to design higher-performance motors is crucial for the development of electric vehicles. Furthermore, unreasonable magnet structure design and magnet slot arrangement lead to large torque ripple, high harmonic content, and weak demagnetization resistance. Summary of the Invention

[0003] In view of this, the present invention provides a rotor, a motor and a permanent magnet synchronous reluctance motor to solve the problems of large torque ripple, high harmonic content and weak anti-demagnetization ability in the prior art.

[0004] This invention provides a rotor, the rotor comprising:

[0005] The magnet includes a first magnet and a second magnet, wherein the first magnet is one of rare earth magnet and ferrite magnet, and the second magnet is the other of rare earth magnet and ferrite magnet.

[0006] A rotor core has multiple magnetic poles arranged at intervals along its circumference. Each magnetic pole has a first magnetic slot group and a second magnetic slot group. The second magnetic slot group is located radially inside the first magnetic slot group and is positioned close to the central axis of the rotor core. The first magnetic slot group includes a first magnetic slot, in which a first magnet is disposed. The second magnetic slot group includes a second magnetic slot, in which a second magnet is disposed.

[0007] Alternatively, the first magnet is a rare-earth magnet, and the second magnet is a ferrite magnet.

[0008] Optionally, the cross-section of the first magnet slot includes a first slot segment and a second slot segment. The first slot segment includes two segments, which are arranged opposite each other along the circumference of the rotor core and are arranged opposite each other on the radial sides of the rotor core. The second slot segment is arranged close to the central axis of the rotor core. One first slot segment, the second slot segment, and the other first slot segment are connected in sequence and arranged in a U-shape. The first magnet is disposed in the second slot segment.

[0009] Further optionally, the first slot segment includes side B13, side B11 and side B12 arranged sequentially; side B11 is disposed away from the central axis of the rotor core; side B13 is located at one end of side B11, and side B13 and side B11 are connected by an arc transition; side B12 is located at the other end of side B11, and side B12 and side B11 are connected by an arc transition.

[0010] Further optionally, the sides B12 of the two first slot segments are both located close to the axis of symmetry of the rotor core, and the sides B13 of the two first slot segments are both located away from the axis of symmetry of the rotor core.

[0011] The included angle between one side B13 of the first slot segment and the other side B13 of the first slot segment is α1, where 84°≤α1≤87°.

[0012] Further optionally, the sides B11 of the two first slot segments are both arc segments and are concentric with the rotor core; the central angle of the sides B11 of the two first slot segments is α2, where 82°≤α1-α2≤83°.

[0013] Further optionally, the second slot segment includes sides B14, B15 and B16 connected in sequence; sides B14 and B16 are arranged opposite to each other along the circumference of the rotor core, and side B15 is arranged close to the central axis of the rotor core; side B14 is connected to side B13 of one of the first slot segments, and side B16 is connected to side B13 of another of the first slot segments.

[0014] The length of the side B14 is b14, which satisfies 1.8mm ≤ b14 ≤ 2.0mm;

[0015] The length of the edge B16 is b16, which satisfies 1.8mm≤b16≤2.0mm.

[0016] Further optionally, one side B11 of the first slot segment forms a first magnetic isolation bridge D11 with the outer edge of the rotor core; the other side B11 of the first slot segment forms a first magnetic isolation bridge D12 with the outer edge of the rotor core.

[0017] Alternatively, the second magnet slot includes two first radial slots, which are arranged opposite each other along the circumference of the rotor core and are V-shaped.

[0018] Further optionally, the cross-section of both first radial slots is polygonal; each polygon of the two first radial slots includes side B21, side B22 and side B23, one end of side B21 is connected to side B23 by an arc transition, the other end of side B21 is connected to side B22 by an arc transition, and side B21 is located away from the central axis of the rotor core.

[0019] Further optionally, the polygons of the two first radial slots also include a side B24 connected to the side B22; the sides B22 of the two first radial slots are both located close to the axis of symmetry of the rotor core, and the sides B24 of the two first radial slots are both located close to the axis of symmetry of the rotor core.

[0020] The included angle between one side B24 of the first radial groove and the other side B24 of the first radial groove is β1, where 7.5°≤α1-β1≤8.5°.

[0021] Further optionally, the edges B23 of the two first radial slots are both located away from the axis of symmetry of the rotor core;

[0022] The included angle between one side B23 of the first radial groove and the other side B23 of the first radial groove is β2, where 1.3≤β2 / β1≤1.4.

[0023] Further optionally, one of the first radial slots forms a second magnetic isolation bridge D21 with the outer edge of the rotor core, and the other first radial slot forms a second magnetic isolation bridge D22 with the outer edge of the rotor core; a second magnetic isolation bridge D23 is formed between the two first radial slots.

[0024] Further optionally, the magnet further includes a third magnet; each of the magnetic poles forms a third magnet group, the third magnet group is located radially inside the second magnet slot group, and the third magnet slot group is disposed close to the central axis of the rotor core;

[0025] The third magnet trough group includes a third magnet trough, and the third magnet is disposed inside the third magnet trough.

[0026] Further optionally, the third magnet is a ferrite magnet; the third magnet slot includes two second radial slots, which are arranged opposite each other along the circumference of the rotor core.

[0027] Further optionally, the cross-sections of the two second radial slots are both polygons; each of the two second radial slot polygons includes side B31, side B32 and side B33, one end of side B31 is connected to side B33 by an arc transition, the other end of side B31 is connected to side B32 by an arc transition, and side B31 is located away from the central axis of the rotor core.

[0028] Further optionally, the polygon of the second radial slot also includes a side B34 connected to the side B32; both sides B32 of the two second radial slots are arranged away from the axis of symmetry of the rotor core, and both sides B34 of the two second radial slots are arranged away from the axis of symmetry of the rotor core.

[0029] The included angle between the side B34 of one second radial groove and the side B34 of another second radial groove is γ1; the included angle between the side B32 of one second radial groove and the side B32 of another second radial groove is γ2; wherein, 1.8≤γ2 / γ1≤1.9.

[0030] Further optionally, one of the second radial slots forms a third magnetic isolation bridge D31 with the outer edge of the rotor core, and the other of the second radial slots forms a third magnetic isolation bridge D32 with the outer edge of the rotor core.

[0031] Further optionally, the third magnet slot also includes a tangential slot, which is located close to the central axis of the rotor core and between the two second radial slots, and the tangential slot and the two second radial slots are arranged in a U-shape.

[0032] Further optionally, a third magnetic bridge D33 is formed between the tangential groove and one of the second radial grooves, and a third magnetic bridge D34 is formed between the tangential groove and another of the second radial grooves.

[0033] Further optionally, the outer edge of the magnetic pole is formed with an elliptical arc, the elliptical arc convex toward the central axis of the rotor core, and the length of the major axis of the ellipse containing the elliptical arc is m and the length of the minor axis is n, wherein 0.1≤n / m≤0.15.

[0034] Further optionally, the cross-section of the first magnet is quadrilateral, the quadrilateral of the first magnet includes a side A11, the side A11 is disposed close to the central axis of the rotor core, and the distance between the midpoint of the side A11 and the central axis of the rotor core is h1;

[0035] The distance between the center point of the ellipse containing the elliptical arc and the central axis of the rotor core is h2, where 8mm≤h2-h1≤9mm.

[0036] The present invention also provides an electric motor, including a stator and a rotor as described in any of the preceding claims.

[0037] The present invention also provides a permanent magnet synchronous reluctance motor, comprising a stator and a rotor as described in any of the preceding claims.

[0038] Compared with the prior art, the main advantages of the present invention are as follows:

[0039] (1) The first magnet is a rare earth magnet, and the second and third magnets are both ferrite magnets; the first magnet slot group, the second magnet slot group and the third magnet slot group are arranged in sequence from the outside to the inside along the radial direction of the rotor core. The first magnet is installed in the first magnet slot, the second magnet is installed in the second magnet slot, and the third magnet is installed in the third magnet slot; the waveform of the air gap magnetic flux density is adjusted to effectively reduce torque pulsation and harmonic content, increase the reluctance torque component, improve the motor's anti-demagnetization ability, and improve the motor's efficiency and performance; effectively reduce leakage flux, increase the magnetic focusing effect, improve the magnet utilization rate, reduce the motor's harmonic loss, and optimize the motor's core loss; the motor power at the highest speed is increased by 62%, and a high output power is maintained, solving the "power drop" problem that occurs in the reluctance motor under high speed conditions;

[0040] (2) The first magnet slot is U-shaped, the second magnet slot is V-shaped, and the third magnet slot is U-shaped. The structure of the magnet slot is optimized and the magnets are reasonably arranged. The harmonics generated by the first, second and third magnets suppress each other. The reliability of the motor is improved, the sinusoidal nature of the air gap magnetic field and the back EMF waveform are effectively improved, the harmonic content of the motor and the peak value of the maximum no-load line back EMF are reduced, the motor torque pulsation is reduced by 6.25%, and the output torque of the motor is increased, so that the motor achieves high performance and high efficiency.

[0041] (3) It can increase the main magnetic flux, achieve magnetic concentration, increase the q-axis inductance, reduce leakage flux, increase the reluctance torque, increase the ratio of quadrature axis inductance to direct axis inductance of the motor, thereby increasing the reluctance torque component, reducing motor vibration and noise; reducing local demagnetization of magnets, improving the overall anti-demagnetization capability of the motor, and improving motor efficiency.

[0042] (4) The positions of the first, second and third magnetic isolation bridges are flexibly arranged. The magnetic isolation bridges can disperse the magnetic bridge stress, which is conducive to increasing the motor speed and power density; reducing leakage flux, ensuring the permanent magnet torque of the motor, increasing the air gap magnetic flux density, increasing the output torque, and improving the output capacity of the motor; reducing the stress on the rotor core, improving the mechanical strength of the rotor, and improving the safety of the rotor.

[0043] (5) The outer edge of the magnetic pole is composed of a circular arc and an elliptical arc. The elliptical arc is close to the first magnet, which can optimize the terminal voltage waveform, improve the sinusoidal nature of the waveform, reduce waveform distortion, increase the sinusoidal nature of the waveform, and reduce the harmonic content. Attached Figure Description

[0044] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0045] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0046] Figure 1 A schematic diagram of the rotor embodiment provided by the present invention;

[0047] Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 A schematic diagram of the rotor embodiment provided by the present invention;

[0048] Figure 8 for Figure 3 Enlarged view of point J in the middle;

[0049] Figure 9 for Figure 7 Enlarged view at point K;

[0050] Figure 10a The figure shows the torque and output power changes of the permanent magnet synchronous reluctance motor before the adoption of this invention.

[0051] Figure 10b The simulation diagram shows the changes in torque and output power of the permanent magnet synchronous reluctance motor after adopting the present invention.

[0052] In the picture:

[0053] 11 - First magnet; 12 - Second magnet; 13 - Third magnet;

[0054] 2-Magnetic pole; 21-First magnetic groove; 22-First radial groove; 23-Second radial groove; 24-Tangential groove; 251-First circular arc; 252-Second circular arc; 26-Elliptical arc. Detailed Implementation

[0055] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0057] Those skilled in the art will understand that the term "and / or" used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0058] Those skilled in the art should also understand that the segment edge, slot edge, and magnetic bridge serial numbers marked in this application, such as edge B13, edge B12, edge B14, edge B15, edge B21, edge B22, second magnetic isolation bridge D21, second magnetic isolation bridge D22, etc., are only for the purpose of distinguishing different structural objects, and the symbols themselves do not have a specific meaning.

[0059] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0060] Existing permanent magnet synchronous motors are generally embedded rare earth permanent magnet motors. Rare earth permanent magnet materials are scarce and expensive, so how to effectively utilize permanent magnet materials to design higher performance motors is crucial to the development of electric vehicles. In addition, due to unreasonable structural design of magnets and arrangement of magnet slots, large torque ripple, high harmonic content and weak anti-demagnetization ability are caused.

[0061] This invention creatively provides a rotor, which includes magnets and a rotor core. The magnets include a first magnet and a second magnet, wherein the first magnet is one of rare earth magnets and ferrite magnets, and the second magnet is another of rare earth magnets and ferrite magnets.

[0062] The rotor core forms multiple magnetic poles arranged circumferentially, and each magnetic pole forms a first magnetic steel slot group and a second magnetic steel slot group; the second magnetic steel slot group is located radially inside the first magnetic steel slot group and is arranged close to the central axis of the rotor core; a first magnet is arranged in the first magnetic steel slot of the first magnetic steel slot group; a second magnet is arranged in the second magnetic steel slot of the second magnetic steel slot group.

[0063] like Figure 10a and Figure 10b As shown, each magnetic pole has two types of magnets in its magnet slot, combining the advantages of both types of magnets. By adjusting the waveform of the air gap magnetic flux density, torque pulsation and harmonic content are effectively reduced, the reluctance torque component is increased, and the motor's anti-demagnetization ability is improved. It also effectively reduces magnetic leakage, increases magnetic focusing effect, improves magnet utilization, reduces motor harmonic losses, and optimizes motor core losses. The motor maintains a high output power at its highest speed, solving the "power drop" problem that occurs in reluctance motors under high-speed conditions.

[0064] magnetic steel

[0065] like Figure 1 and Figure 2 As shown, this embodiment provides a rotor, which includes magnets and a rotating core. The magnets include a first magnet 11, a second magnet 12, and a third magnet 13. The first magnet 11 is a rare earth magnet, and the second magnet 12 and the third magnet 13 are ferrite magnets. According to the actual situation, a certain magnet can be flexibly set into the corresponding magnet slot to reduce torque pulsation and harmonic content, improve the motor's anti-demagnetization ability, reduce leakage flux, and increase the magnetizing effect.

[0066] Magnet trough assembly

[0067] <First Magnet Slot Assembly>

[0068] like Figure 2 , Figure 3 , Figure 4 and Figure 8 As shown, the rotor core forms multiple magnetic poles 2, which are spaced apart circumferentially along the rotor core. Each magnetic pole 2 is symmetrical about the axis of symmetry I of the rotor core, and each magnetic pole 2 forms a first magnetic slot group, which includes a first magnetic slot 21, in which a first magnet 11 is disposed. This can increase the output torque, reduce torque pulsation, improve anti-demagnetization capability, and increase motor power under high-speed conditions. Specifically, under high-speed conditions, the motor power can be increased by 62%.

[0069] Furthermore, the cross-section of the first magnetic slot 21 includes a first slot segment and a second slot segment; the first slot segment includes two segments, which are arranged opposite each other along the circumference of the rotor core and are arranged opposite each other on the radial sides of the rotor core; the two first slot segments have the same structure, and the first slot segment includes side B13, side B11 and side B12 arranged sequentially; side B11 is located away from the central axis of the rotor core and close to the outer edge of the magnetic pole 2; side B13 is located at one end of side B11, and side B13 is connected to side B11 by an arc transition; side B12 is located at the other end of side B11, and side B12 is connected to side B11 by an arc transition.

[0070] The sides B12 of the two first slot segments are both set close to the axis of symmetry I of the rotor core, and the sides B13 of the two first slot segments are both set away from the axis of symmetry I of the rotor core.

[0071] The included angle between the edge B13 of one first groove segment and the edge B13 of another first groove segment is α1, where 84°≤α1≤87°; preferably, α1=85°;

[0072] Both sides B11 of the two first slot segments are circular arc segments and are concentric with the rotor core; the central angle of the sides B11 of the two first slot segments is α2, where 2°≤α2≤3°; preferably, α2=2.27°;

[0073] The condition that α1 and α2 satisfy 82°≤α1-α2≤83° can reduce the no-load harmonic content and torque pulsation, and improve the reluctance torque.

[0074] Furthermore, the second slot segment is positioned close to the central axis of the rotor core; a first slot segment, a second slot segment, and another first slot segment are sequentially connected and arranged in a U-shape; a first magnet 11 is disposed within the second slot segment; the second slot segment includes sequentially connected sides B14, B15, and B16; sides B14 and B16 are arranged opposite each other along the circumference of the rotor core, and sides B14 and B16 are symmetrically arranged with respect to the axis of symmetry I of the rotor core; side B15 is positioned close to the central axis of the rotor core; side B14 is connected to side B13 of one first slot segment, and side B16 is connected to side B13 of another first slot segment;

[0075] Sides B14, B15 and B16 are attached to the first magnet 11 to fix the first magnet 11 and ensure the mechanical strength of the rotor under high-speed conditions.

[0076] The length of side B14 is b14, satisfying 1.8mm≤b14≤2.0mm; the length of side B16 is b16, satisfying 1.8mm≤b16≤2.0mm; preferably, b14=b16=2mm.

[0077] <Second Magnet Slot Assembly>

[0078] like Figure 2 and Figure 5 As shown, each magnetic pole 2 also forms a second magnetic steel slot group, which is located radially inside the first magnetic steel slot group and is arranged close to the central axis of the rotor core; the second magnetic steel slot group includes a second magnetic steel slot, and a second magnet 12 is arranged in the second magnetic steel slot;

[0079] The second magnet slot has two first radial slots 22, which are arranged opposite each other along the circumference of the rotor core and in a V-shape. The intersection of the extension line of one first radial slot 22 and the extension line of the other radial slot is close to the central axis of the rotor core. A second magnet 12 is provided in each first radial slot 22.

[0080] Furthermore, the two first radial grooves 22 have the same structure, and the cross-section of the first radial groove 22 is polygonal; the polygon of the first radial groove 22 includes side B21, side B22 and side B23, one end of side B21 is connected to side B23 by a circular arc transition, the other end of side B21 is connected to side B22 by a circular arc transition, and side B21 is located away from the central axis of the rotor core and close to the outer edge of the rotor core.

[0081] In addition, the polygon of the first radial slot 22 also includes a side B24 connected to the side B22; the sides B22 of the two first radial slots are both located close to the axis of symmetry of the rotor core, and the sides B24 of the two first radial slots are both located close to the axis of symmetry of the rotor core.

[0082] The included angle between the side B24 of one first radial slot 22 and the side B24 of another first radial slot 22 is β1, where 7.5°≤α1-β1≤8.5°, which can reduce the no-load harmonic content and torque pulsation, and improve the reluctance torque;

[0083] Both sides B23 of the first radial slots are located away from the axis of symmetry of the rotor core; the included angle between the side B23 of one first radial slot 22 and the side B23 of the other first radial slot 22 is β2, where 1.3≤β2 / β1≤1.4; preferably, β2 / β1=1.37;

[0084] The polygon of the first radial groove 22 also includes a side B25 connected to side B24.

[0085] <Third Magnet Slot Assembly>

[0086] like Figure 2 and Figure 6As shown, each magnetic pole 2 also forms a third magnetic steel slot group, which is located radially inside the second magnetic steel slot group and is set close to the central axis of the rotor core; that is, the first magnetic steel slot group, the second magnetic steel slot group and the third magnetic steel slot group are arranged sequentially from the outside to the inside along the radial direction of the rotor core; the third magnetic steel slot group includes a third magnetic steel slot, and a third magnet 13 is arranged in the third magnetic steel slot;

[0087] The third magnet slot includes two second radial slots 23, which are arranged opposite each other along the circumference of the rotor core and extend along the radial direction of the rotor core.

[0088] Furthermore, the two second radial slots 23 have the same structure. The cross-section of the second radial slot 23 is polygonal. The polygon of the second radial slot 23 includes side B31, side B32 and side B33. One end of side B31 is connected to side B33 by an arc transition, and the other end of side B31 is connected to side B32 by an arc transition. Side B31 is located away from the central axis of the rotor core and close to the outer edge of the magnetic pole 2.

[0089] The polygon of the second radial slot 23 also includes a side B34 connected to side B32; both side B32 and side B34 are located close to the axis of symmetry I of the rotor core; the polygon of the second radial slot 23 also includes a side B35 connected to side B34.

[0090] The included angle between the side B34 of one second radial slot 23 and the side B34 of another second radial slot 23 is γ1; the included angle between the side B32 of one second radial slot 23 and the side B32 of another second radial slot 23 is γ2; wherein, 1.8≤γ2 / γ1≤1.9; preferably, γ2 / γ1=1.86; this can increase the q-axis inductance, improve the reluctance torque, reduce torque pulsation, and improve motor efficiency.

[0091] In addition, the third magnet slot also includes a tangential slot 24, which is located near the central axis of the rotor core and between the two second radial slots. The tangential slot 24 and the two second radial slots are arranged in a U-shape, and the tangential slot 24 extends tangentially along the magnetic pole 2. The cross-section of the tangential slot 24 is trapezoidal, and the trapezoidal shape of the tangential slot 24 includes oppositely arranged sides B36 and B37. Side B36 is located near side B35 of one second radial slot 23, and side B37 is located near side B35 of the other second radial slot 23.

[0092] In summary, the first magnet slot has a U-shaped structure, the second magnet slot has a V-shaped structure, and the third magnet slot has a U-shaped structure. Optimizing the magnet slot structure and rationally arranging the magnets allows for mutual suppression of harmonics generated by the first, second, and third magnets. This improves motor reliability, effectively reduces the sinusoidal nature of the air gap magnetic field and the back EMF waveform, lowers the motor's harmonic content and the peak value of the maximum no-load line back EMF, reduces motor torque ripple by 6.25%, and increases the motor's output torque, thus achieving high performance and high efficiency. It also increases the main magnetic flux, achieves magnetization, increases the q-axis inductance, reduces leakage flux, and increases reluctance torque. This increases the ratio of quadrature-axis inductance to direct-axis inductance, thereby increasing the reluctance torque component and reducing motor vibration and noise. Furthermore, it reduces local demagnetization of the magnets, improves the motor's overall demagnetization resistance, and increases motor efficiency.

[0093] Magnetic bridge

[0094] <First Magnetic Bridge>

[0095] like Figure 2 and Figure 3 As shown, the edge B11 of one first slot segment forms a first magnetic isolation bridge D11 with the outer edge of the rotor core; the edge B11 of another first slot segment forms a first magnetic isolation bridge D12 with the outer edge of the rotor core; the first magnetic isolation bridge can reduce magnetic leakage, increase air gap magnetic flux density, increase output torque, and improve the mechanical strength of the rotor.

[0096] <Second Magnetic Bridge>

[0097] like Figure 2 and Figure 3 As shown, the side B21 of one first radial slot 22 forms a second magnetic isolation bridge D21 with the outer edge of the rotor core, and the side B21 of the other first radial slot 22 forms a second magnetic isolation bridge D22 with the outer edge of the rotor core; the second magnetic isolation bridge D21 and the second magnetic isolation bridge D22 are symmetrically arranged with respect to the axis of symmetry I of the rotor core.

[0098] A second magnetic bridge D23 is formed between the two first radial slots 22; the second magnetic bridge can reduce magnetic leakage, increase air gap magnetic flux density, increase output torque, and improve the mechanical strength of the rotor; specifically, a second magnetic bridge D23 is formed between the side B25 of one first radial slot 22 and the side B25 of the other first radial slot 22.

[0099] <Third magnetic isolation bridge>

[0100] like Figure 2 and Figure 3As shown, the side B31 of one second radial slot 23 forms a third magnetic isolation bridge D31 with the outer edge of the rotor core, and the side B31 of another second radial slot 23 forms a third magnetic isolation bridge D32 with the outer edge of the rotor core; the third magnetic isolation bridge D31 and the third magnetic isolation bridge D32 are symmetrically arranged with respect to the axis of symmetry I of the rotor core.

[0101] A third magnetic isolation bridge D33 is formed between the tangential slot 24 and a second radial slot 23, and a third magnetic isolation bridge D34 is formed between the tangential slot 24 and another second radial slot 23. The third magnetic isolation bridge can reduce leakage flux, increase air gap magnetic flux density, increase output torque, and improve the mechanical strength of the rotor. Specifically, side B36 and side B35 of a second radial slot 23 form a third magnetic isolation bridge D31, and side B37 and side B35 of another second radial slot 23 form a third magnetic isolation bridge D32.

[0102] In summary, magnetic isolation bridges are formed between the first magnetic slot and the outer edge of the magnetic pole, between the first radial slot and the outer edge of the magnetic pole, between the two first radial slots, between the second radial slot and the outer edge of the magnetic pole, between the second radial slot and the tangential slot, and between the two second radial slots. The positions of the first, second, and third magnetic isolation bridges are flexibly arranged. The magnetic isolation bridges can disperse the magnetic bridge stress, which is beneficial to increasing the motor speed and power density; reducing leakage flux, ensuring the permanent magnet torque of the motor, increasing the air gap magnetic flux density, increasing the output torque, and improving the output capacity of the motor; reducing the stress on the rotor core, improving the mechanical strength of the rotor, and improving the safety of the rotor.

[0103] outer edge of magnetic pole

[0104] like Figure 2 , Figure 7 and Figure 9 As shown, the outer edge of the magnetic pole 2 is composed of a circular arc and an elliptical arc 26. The circular arc includes a first circular arc 251 and a second circular arc 252. The first circular arc 251 and the second circular arc 252 are arranged opposite to each other along the circumference of the magnetic pole 2 and are symmetrical about the axis of symmetry I of the rotor core. The elliptical arc 26 is located between the first circular arc 251 and the second circular arc 252 and is close to the first magnet 11. It can optimize the terminal voltage waveform, improve the sinusoidal nature of the waveform, reduce waveform distortion, increase the sinusoidal nature of the waveform, and reduce the harmonic content.

[0105] Elliptical arc 26 convexes toward the central axis of the rotor core, and the length of the major axis of the ellipse containing elliptical arc 26 is m and the length of the minor axis is n, 15mm≤m≤17mm, preferably m=16mm; wherein, 0.1≤n / m≤0.15; preferably, (b / a)=0.12; specifically, the endpoint of the major axis of the ellipse containing elliptical arc 26 is MN, and the line containing MN is perpendicular to the axis of symmetry I of the rotor core;

[0106] The first magnet 11 has a quadrilateral cross-section, which includes a side A11. Side A11 is located close to the central axis of the rotor core, and the distance between the midpoint of side A11 and the central axis of the rotor core is h1. Specifically, the midpoint of side A11 is T, the center point of the rotor core is O, and the distance between point T and point O is h1. 67mm ≤ h1 ≤ 70mm; preferably, h1 = 69mm.

[0107] The distance between the center point of the ellipse containing elliptical arc 26 and the central axis of the rotor core is h2. Specifically, the center point of the ellipse containing elliptical arc 26 is Q, and the distance between point Q and point O is h2; where 8mm≤h2-h1≤9mm; preferably, h2-h1=8.74mm;

[0108] It can reduce motor torque ripple, increase output torque, and improve motor power under high-speed conditions.

[0109] This embodiment also provides an electric motor, including a stator and a rotor as described in any of the above embodiments;

[0110] This embodiment also provides a permanent magnet synchronous reluctance motor, including a stator and a rotor as described in any of the above embodiments;

[0111] This embodiment also provides a logistics vehicle motor, including a stator and a rotor as described in any of the above embodiments. The load capacity of the logistics vehicle is in the range of [3t, 4.5t], the outer diameter of the stator is 230mm, the peak power range is [70kW, 80kW], the peak torque range is [270Nm, 300Nm], and the peak speed is [9000rpm, 12000rpm]. Through the above-mentioned rotor outer edge design, magnet slot design, and magnet design, the "power drop" problem under high-speed conditions is effectively solved. The motor power at the highest speed is increased by 62%, the output torque is increased, and the torque pulsation is reduced by 6.25%. The overall anti-demagnetization capability of the motor is improved. The mechanical strength of the rotor is guaranteed, and the safety of the rotor is improved.

[0112] Exemplary embodiments of this disclosure have been specifically shown and described above. It should be understood that this disclosure is not limited to the detailed structures, arrangements, or implementations described herein; rather, this disclosure is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A rotor characterized by, The rotor comprises: magnetic steel, including first magnetic steel and second magnetic steel, and the first magnetic steel is one of rare earth magnetic steel and ferrite magnetic steel, and the second magnetic steel is the other of rare earth magnetic steel and ferrite magnetic steel; rotor core, forming a plurality of magnetic poles, a plurality of the magnetic poles are arranged along the circumference of the rotor core; each of the magnetic poles is formed with a first magnetic steel slot group and a second magnetic steel slot group, the second magnetic steel slot group is located on the radial inner side of the first magnetic steel slot group, and the second magnetic steel slot group is arranged close to the central axis of the rotor core; the first magnetic steel slot group includes a first magnetic steel slot, and the first magnetic steel is arranged in the first magnetic steel slot; the second magnetic steel slot group includes a second magnetic steel slot, and the second magnetic steel is arranged in the second magnetic steel slot; the cross section of the first magnetic steel slot includes a first slot section, the first slot section includes two, two first slot sections are arranged along the circumference of the rotor core, and two first slot sections are oppositely arranged on the radial two sides of the rotor core; two first slot sections each include a side B13 and a side B11 arranged in sequence; the side B11 is arranged away from the central axis of the rotor core; the side B13 is located at one end of the side B11, and the side B13 is circularly arc transitionally connected with the side B11; the side B13 of two first slot sections is arranged away from the symmetry axis of the rotor core, and the included angle between the side B13 of one first slot section and the side B13 of another first slot section is α1; wherein, 84°≤α1≤87°; the side B11 of two first slot sections is a circular arc section and has the same center as the rotor core; the central angle of the side B11 of two first slot sections is α2; wherein, 82°≤α1-α2≤83°.

2. The rotor of claim 1, wherein The first magnetic steel is rare earth magnetic steel, and the second magnetic steel is ferrite magnetic steel.

3. The rotor of claim 2, wherein The cross section of the first magnetic steel slot includes a second slot section; the second slot section is arranged close to the central axis of the rotor core, and along the circumference of the rotor core, the second slot section is located between two first slot sections; one end of the second slot section is connected with one first slot section, and the other end of the second slot section is connected with another first slot section; the second slot section and two first slot sections are arranged in a U shape; the first magnetic steel is arranged in the second slot section.

4. The rotor of claim 3, wherein Two first slot sections each include a side B12; the side B12 is located at the other end of the side B11, and the side B12 is circularly arc transitionally connected with the side B11.

5. The rotor of claim 4, wherein The side B12 of two first slot sections is arranged close to the symmetry axis of the rotor core.

6. The rotor of claim 4, wherein The second slot section includes a side B14, a side B15 and a side B16 connected in sequence; the side B14 and the side B16 are oppositely arranged along the circumference of the rotor core, and the side B15 is arranged close to the central axis of the rotor core; the side B14 is connected with the side B13 of one first slot section, and the side B16 is connected with the side B13 of another first slot section; The length of the side B14 is b14, and 1.8mm≤b14≤2.0mm is satisfied; The length of the side B16 is b16, and 1.8mm≤b16≤2.0mm is satisfied.

7. The rotor of claim 4, wherein One side B11 of one of the first slot segments forms a first magnetic isolation bridge D11 with the outer edge of the rotor core; and the other side B11 of the other first slot segment forms a first magnetic isolation bridge D12 with the outer edge of the rotor core.

8. The rotor of claim 5, wherein The second magnetic steel slot comprises two first radial slots, and the two first radial slots are oppositely arranged along the circumference of the rotor core and are arranged in a V shape.

9. The rotor of claim 8, wherein The cross sections of the two first radial slots are polygons, and the polygons of the two first radial slots each comprise a side B21, a side B22, and a side B23. One end of the side B21 is connected to the side B23 in a circular arc transition manner, the other end of the side B21 is connected to the side B22 in a circular arc transition manner, and the side B21 is arranged away from the central axis of the rotor core.

10. The rotor of claim 9, wherein The polygons of the two first radial slots each further comprise a side B24 connected to the side B22. The side B22 of each of the two first radial slots is arranged close to the symmetry axis of the rotor core, and the side B24 of each of the two first radial slots is arranged close to the symmetry axis of the rotor core. The included angle between the side B24 of one of the first radial slots and the side B24 of the other first radial slot is β1, and 7.5°≤α1-β1≤8.5° is satisfied.

11. The rotor of claim 10, wherein The side B23 of each of the two first radial slots is arranged away from the symmetry axis of the rotor core. The included angle between the side B23 of one of the first radial slots and the side B23 of the other first radial slot is β2, and 1.3≤β2 / β1≤1.4 is satisfied.

12. The rotor of claim 8, wherein One of the first radial slots forms a second magnetic isolation bridge D21 with the outer edge of the rotor core, and the other first radial slot forms a second magnetic isolation bridge D22 with the outer edge of the rotor core. A second magnetic isolation bridge D23 is formed between the two first radial slots.

13. The rotor of claim 1, wherein The magnetic steel further comprises third magnetic steel. Each of the magnetic poles is formed with a third magnetic steel group. The third magnetic steel group is located on the radially inner side of the second magnetic steel slot group, and the third magnetic steel slot group is arranged close to the central axis of the rotor core. The third magnetic steel slot group comprises third magnetic steel slots, and the third magnetic steel slots are arranged with the third magnetic steel.

14. The rotor of claim 13, wherein The third magnetic steel is a ferrite magnetic steel. The third magnetic steel slot comprises two second radial slots, and the two second radial slots are oppositely arranged along the circumference of the rotor core.

15. The rotor of claim 14, wherein The cross sections of the two second radial slots are polygons, and the polygons of the two second radial slots each comprise a side B31, a side B32, and a side B33. One end of the side B31 is connected to the side B33 in a circular arc transition manner, the other end of the side B31 is connected to the side B32 in a circular arc transition manner, and the side B31 is arranged away from the central axis of the rotor core.

16. The rotor of claim 15, wherein The polygons of the two second radial slots each further comprise a side B34 connected to the side B32. The side B32 of each of the two second radial slots is arranged away from the symmetry axis of the rotor core, and the side B34 of each of the two second radial slots is arranged away from the symmetry axis of the rotor core. An included angle between one edge B34 of the second radial slot and another edge B34 of the second radial slot is γ1; an included angle between one edge B32 of the second radial slot and another edge B32 of the second radial slot is γ2; wherein 1.8≤γ2 / γ1≤1.

9.

17. The rotor of claim 14, wherein One of the second radial slots forms a third magnetic isolation bridge D31 with an outer edge of the rotor core, and another of the second radial slots forms a third magnetic isolation bridge D32 with the outer edge of the rotor core.

18. The rotor of claim 14, wherein The third magnetic steel slot further comprises a tangential slot, which is arranged close to the central axis of the rotor core and between two second radial slots, and the tangential slot and the two second radial slots are arranged in a U shape.

19. The rotor of claim 18, wherein The tangential slot and one of the second radial slots form a third magnetic isolation bridge D33, and the tangential slot and another of the second radial slots form a third magnetic isolation bridge D34.

20. The rotor of claim 3, wherein An outer edge of the magnetic pole is formed with an elliptical arc, the elliptical arc is convex to the central axis of the rotor core, and the length of the major axis of the ellipse where the elliptical arc is located is m and the length of the minor axis is n, wherein 0.1≤n / m≤0.

15.

21. The rotor of claim 20, wherein The cross section of the first magnetic steel is a quadrilateral, and the quadrilateral of the first magnetic steel comprises an edge A11, the edge A11 is arranged close to the central axis of the rotor core, and the distance between the midpoint of the edge A11 and the central axis of the rotor core is h1. The distance between the center point of the ellipse where the elliptical arc is located and the central axis of the rotor core is h2, wherein 8mm≤h2-h1≤9mm.

22. An electric machine characterized by A motor comprising a stator and a rotor according to any one of claims 1-21.

23. A permanent magnet synchronous reluctance machine, characterized by, A motor comprising a stator and a rotor according to any one of claims 1-21.

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