A novel rare-earth hybrid permanent magnet motor

Abstract

This invention discloses a novel rare-earth hybrid permanent magnet motor, which employs a rare-earth hybrid permanent magnet alternating pole asymmetrical rotor. The rotor includes a rotor core, permanent magnets, permanent magnet embedding slots, and magnetic bridges. The rotor consists of multiple pairs of poles circumferentially, each pair consisting of a core pole and a permanent magnet pole. Specifically, the rotor core is used as the core pole to replace part of the permanent magnet poles, forming a magnetic pole structure where permanent magnet poles and core poles are alternately distributed around the rotor circumference. Each permanent magnet pole has a large and two small permanent magnet embedding slots with asymmetrical spatial positions. The embedding slots contain permanent magnets with the same magnetization direction but different sizes, and are asymmetrical. The large permanent magnet embedding slot contains rare-earth permanent magnets, while the two small permanent magnet embedding slots contain non-rare-earth permanent magnets. A magnetic bridge is located at the end of each permanent magnet near the air gap, and magnetic bridges are also provided between the permanent magnets within each permanent magnet pole. This rotor structure reduces the amount of rare-earth permanent magnets used, lowers motor costs, and can improve torque density by utilizing the magnetic field deflection effect.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motor technology, specifically relating to a novel rare-earth hybrid permanent magnet motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are synchronous motors that use permanent magnet materials as rotor excitation. They possess advantages such as simple structure, high power density, low loss, high power factor, good control performance, high reliability, wide applicability, and low maintenance costs, making them promising for widespread application in industry and other fields. However, the manufacture of PMSMs requires the consumption of large quantities of rare-earth permanent magnet materials. While these materials offer superior performance, their high cost limits the promotion and application of PMSMs. Therefore, how to reduce the amount of permanent magnet materials used in PMSMs while ensuring motor performance and reliability is a crucial issue in the current field of PMSMs.

[0003] To address this issue, there are currently two main approaches: one is to use relatively inexpensive non-rare earth permanent magnet materials, such as ferrite materials, as rotor excitation; the other is to optimize the motor structure to minimize the use of rare earth permanent magnet materials while still meeting the motor's performance requirements.

[0004] Chinese patent application CN101820238A discloses a permanent magnet synchronous motor with an asymmetrical rotor. The only difference is that the rotor magnetic barrier adopts an asymmetrical design. The purpose is to give the embedded permanent magnet motor a skewed pole effect and reduce torque pulsation. However, the size and spatial position of the permanent magnet do not show asymmetry. The amount of permanent magnet material used is still relatively large, and it does not belong to the rare earth permanent magnet structure. The literature [W. Ren, Q. Xu, Q. Li and L. Zhou, "Reduction of Cogging Torque and Torque Ripple in Interior PM Machines With Asymmetrical V-Type Rotor Design," in IEEE Transactions on Magnetics, vol. 52, no. 7, pp. 1-5, July 2016, Art no. 8104105] proposes a permanent magnet synchronous motor with an asymmetrical V-type magnetic pole rotor. However, it uses an alternating distribution of N-pole and S-pole permanent magnets, instead of an alternating pole structure of permanent magnet poles and iron core poles. Furthermore, the permanent magnets only involve a single rare-earth permanent magnet material, and the amount of permanent magnet material used is still relatively large.

[0005] Compared to the N-pole permanent magnets and S-pole permanent magnets of the permanent magnet rotor mentioned above, the alternating pole rotor replaces all the N-pole permanent magnets or S-pole permanent magnets with an iron core. The permanent magnet poles and the adjacent iron core poles form a pair of poles, which can greatly reduce the amount of permanent magnets used. At the same time, the magnetic poles adopt an asymmetrical structure, which aims to generate effective reluctance torque and increase torque density.

[0006] Therefore, it is necessary to design a new type of rare-earth hybrid permanent magnet motor that uses an alternating pole asymmetric rotor. Under the premise of meeting the motor performance requirements, the rotor structure is improved and some rare-earth permanent magnets are replaced with non-rare-earth permanent magnets to reduce the motor cost as much as possible while ensuring the reliability of the structure. Summary of the Invention

[0007] In view of the above, the present invention provides a novel rare-earth hybrid permanent magnet motor, which adopts an alternating pole asymmetric rotor and a magnetic pole structure that combines rare-earth permanent magnets and ferrites. This can solve the problem that the large demand for rare-earth permanent magnet materials in traditional permanent magnet synchronous motors limits their application in cost-constrained situations.

[0008] A novel rare-earth hybrid permanent magnet motor employs an alternating pole asymmetrical rotor, comprising a rotor core with a rotor shaft hole at its center. The rotor consists of multiple pole pairs circumferentially, each pair consisting of a core pole and a permanent magnet pole. The rotor core serves as the core pole, replacing half of the magnetic poles. The permanent magnet poles are composed of permanent magnets of the same polarity but different sizes and materials, forming an alternating pole structure with permanent magnet poles and core poles distributed around the rotor circumference. Each permanent magnet pole has a large and two small asymmetrically positioned permanent magnet insertion slot. These slots contain permanent magnets of the same magnetization direction but different sizes and asymmetrical arrangement. The large slot contains rare-earth permanent magnets, while the two smaller slots contain non-rare-earth permanent magnets. A magnetic bridge is located at the end of each permanent magnet near the air gap, and magnetic bridges are also present between the permanent magnets within each pole. The arrangement of the permanent magnet insertion slots, permanent magnets, and magnetic bridges is identical within each pole pair.

[0009] Furthermore, the magnetic pole structure is V-shaped, with the magnetic pole centerline bisecting the mechanical angle that each pair of poles crosses on the rotor circumference. Each permanent magnet pole is provided with a first permanent magnet embedding slot, a second permanent magnet embedding slot, and a third permanent magnet embedding slot that are asymmetrically distributed about the magnetic pole centerline. The first permanent magnet embedding slot spans both sides of the magnetic pole centerline, while the second and third permanent magnet embedding slots are located on the same side of the magnetic pole centerline. The first, second, and third permanent magnets are respectively embedded in the first, second, and third permanent magnet embedding slots. The magnetization directions of the first, second, and third permanent magnets are perpendicular to the long side of their respective permanent magnets and simultaneously point towards the air gap or away from the air gap.

[0010] Furthermore, the first permanent magnet is a single-layer permanent magnet, the second permanent magnet and the third permanent magnet constitute a double-layer permanent magnet, and the first permanent magnet, the second permanent magnet and the third permanent magnet constitute a single-double-layer mixed magnetic pole.

[0011] Furthermore, the first permanent magnet is made of rare earth permanent magnet material (such as neodymium iron boron), while the second and third permanent magnets are made of non-rare earth permanent magnet material (such as ferrite). The first, second, and third permanent magnets are all different in size, and the volume of the first permanent magnet is larger than that of the second and third permanent magnets. The first, second, and third permanent magnets constitute a hybrid permanent magnet material pole.

[0012] Furthermore, the first, second, and third permanent magnet embedding slots are all equipped with slots without permanent magnets to adjust motor performance.

[0013] Furthermore, the first permanent magnet embedding slot, the second permanent magnet embedding slot, and the third permanent magnet embedding slot are all provided with permanent magnet assembly slots for assembling permanent magnets.

[0014] Furthermore, ventilation and weight reduction holes are evenly arranged along the circumference of the rotor core, and the ventilation and weight reduction holes are only arranged at the core pole position of each pair of poles.

[0015] Furthermore, the rotor shaft hole is provided with a keyway and a key.

[0016] Furthermore, in addition to the aforementioned V-shaped magnetic pole, the magnetic pole structure can also be ⊽-shaped, U-shaped, or arc-shaped, etc.

[0017] Based on the above technical solution, the present invention has the following beneficial technical effects:

[0018] 1. This invention significantly reduces the amount of permanent magnets used and substantially lowers costs through an alternating pole rotor structure design.

[0019] 2. This invention reduces the amount of rare earth permanent magnets used by replacing some rare earth permanent magnets with non-rare earth permanent magnets, thus significantly reducing costs.

[0020] 3. This invention reduces the difference in current lead angle between the maximum permanent magnet torque and the maximum reluctance torque of the motor through an asymmetrical magnetic pole design, thereby improving the torque density of the motor.

[0021] 4. By selecting appropriate permanent magnet embedding slots and the size, number, and position of permanent magnets, this invention can ensure the output performance of the motor while maintaining low cost. Attached Figure Description

[0022] Figure 1 This is a two-dimensional cross-sectional schematic diagram of the novel rare-earth hybrid permanent magnet motor according to an embodiment of the present invention.

[0023] Figure 2 This is a three-dimensional schematic diagram of a novel rare-earth hybrid permanent magnet motor according to an embodiment of the present invention.

[0024] Figure 3 This is a three-dimensional schematic diagram of the alternating pole asymmetric rotor of the novel rare-earth hybrid permanent magnet motor according to an embodiment of the present invention.

[0025] Figure 4 (a) is a vector diagram of a symmetrical rotor permanent magnet synchronous motor in the dq coordinate system.

[0026] Figure 4 (b) is a vector diagram of an asymmetric rotor permanent magnet synchronous motor in the dq coordinate system.

[0027] Figure 5 This diagram illustrates the torque-current lead angle characteristics of a symmetrical rotor permanent magnet synchronous motor and an asymmetrical rotor permanent magnet synchronous motor.

[0028] Figure 6 This is a diagram showing the magnetic field distribution of the armature of the novel rare-earth hybrid permanent magnet motor of the present invention when the armature is open.

[0029] Figure 7 This is a schematic diagram of the structure of the extremely rare earth mixed permanent magnet alternating polar asymmetric external rotor in Embodiment 6 of the present invention.

[0030] In the diagram: 1—Center of motor rotation shaft; 2—Positive direction of rotor rotation; 3—Rotor core; 4—Rotor shaft hole; 5—Protruding key; 6—Keyway; 7—Embedded slot for permanent magnet #1; 8—Embedded slot for permanent magnet #2; 9—Embedded slot for permanent magnet #3; 10—Permanent magnet #1; 11—Permanent magnet #2; 12—Permanent magnet #3; 13—Main magnetization direction of permanent magnet #1; 14—Main magnetization direction of permanent magnet #2; 15—Main magnetization direction of permanent magnet #3; 16—Long side of permanent magnet #1; 17—Long side of permanent magnet #2; 18—Long side of permanent magnet #3; 19—Magnetic bridge of permanent magnet #1 near the air gap; 20—Permanent magnet #2 near the air gap. Magnetic bridge, 21—Magnetic bridge near the air gap side of permanent magnet No. 3, 22—Magnetic bridge between permanent magnet No. 1 and permanent magnet No. 2, 23—Magnetic bridge between permanent magnet No. 2 and permanent magnet No. 3, 24—Slot No. 1 without permanent magnet, 25—Slot No. 2 without permanent magnet, 26—Slot No. 3 without permanent magnet, 27—Slot No. 4 without permanent magnet, 28—Slot No. 5 without permanent magnet, 29—Slot No. 6 without permanent magnet, 30—Assembly slot of permanent magnet No. 1, 31—Assembly slot of permanent magnet No. 2, 32—Assembly slot of permanent magnet No. 3, 33—Ventilation and weight reduction hole, 34—Magnetic pole center line, 35—Mechanical angle crossed by a pair of poles on the rotor circumference, 36—Stator core, 37—Stator winding. Detailed Implementation

[0031] To describe the present invention in more detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] like Figure 2 As shown, this embodiment provides a novel rare-earth hybrid permanent magnet motor, including a stator and a rotor. The stator includes a stator core 36 and a stator winding 37; the rotor adopts an alternating pole asymmetric rotor, such as... Figure 3 As shown, permanent magnet poles are composed of permanent magnets with the same polarity but different sizes and materials; alternating pole structure means that permanent magnet poles and iron core poles are alternately distributed around the rotor circumference, and the permanent magnets of each permanent magnet pole have the same polarity. More precisely, the number of permanent magnet poles and the number of pole pairs of the rotor are equal; asymmetrical magnetic pole means that the slots or permanent magnets that make up the permanent magnet poles of the rotor are distributed in a way that makes it impossible to find a structural axis of symmetry on the permanent magnet poles.

[0034] Next, we select a cross-section that can characterize this embodiment as a reference section, such as... Figure 1As shown, one direction is defined as positive along the center 1 of the motor's rotation axis. Taking the positive axial direction as a reference, the positive rotation direction 2 is defined. A rotor shaft hole 4 is machined at the center of the rotor core 3. The rotor shaft hole can be assembled with a key 5 or a keyway 6. The rotor core is divided into several equal parts along the circumference according to the required number of pole pairs. Taking the magnetic pole center line 34 of each part as a reference, the rotor is machined on both sides with the following slots: permanent magnet embedding slot 7, permanent magnet embedding slot 8, permanent magnet embedding slot 9, slot 24 (no permanent magnet), slot 25 (no permanent magnet), slot 26 (no permanent magnet), slot 27 (no permanent magnet), slot 28 (no permanent magnet), slot 29 (no permanent magnet), slot 30 (no permanent magnet), slot 31 (no permanent magnet), and slot 32 (no permanent magnet). Permanent magnet 10, permanent magnet 11, and permanent magnet 12 are embedded in permanent magnet 1 slot 7, permanent magnet 2 slot 8, and permanent magnet 3 slot 9 according to their corresponding dimensions and materials. The magnetization directions of permanent magnet 10, permanent magnet 2, and permanent magnet 3 are perpendicular to the long side 16, long side 17, and long side 18 of permanent magnet 1, respectively, and simultaneously point towards the air gap or away from the air gap. Permanent magnet 10 uses rare earth permanent magnet material (such as neodymium iron boron), while permanent magnet 11 and permanent magnet 3 use non-rare earth permanent magnet material (such as ferrite). The asymmetry of the rotor structure is reflected in the asymmetrical distribution of these slots on both sides of the magnetic pole centerline 34 and the asymmetry of the slot size. It is also reflected in the different sizes of the permanent magnets embedded in each pole and the different number of permanent magnet layers on both sides of the magnetic pole centerline 34. The hybridity of the rotor is reflected in the use of different permanent magnet materials for permanent magnet 10, permanent magnet 11, and permanent magnet 12. To ensure mechanical strength, magnetic bridges are provided at the end of the permanent magnets near the air gap, namely magnetic bridge 19 for permanent magnet 1, magnetic bridge 20 for permanent magnet 2, and magnetic bridge 21 for permanent magnet 3. Magnetic bridges are also required between the permanent magnets within the permanent magnet poles. Magnetic bridges 22 and 23 are provided between permanent magnet 1 and permanent magnet 2, and between permanent magnet 2 and permanent magnet 3, respectively. Ventilation and weight reduction holes 33 can be machined on the rotor core as needed. After the permanent magnets are embedded in each pair of poles, the distribution, size and polarity of the permanent magnets and slots are completely the same, and finally the alternating pole asymmetric rotor of the novel rare earth hybrid permanent magnet motor is obtained.

[0035] In this embodiment, the alternating pole asymmetric rotor of the novel rare earth hybrid permanent magnet motor is used as a rotating motor. When the magnetic field of the motor on both sides of the stator and rotor passes through the air gap, it can be along the radial or axial direction. The direction of motion of the rotating magnetic field can be in the same plane or different planes as the direction of motion of the rotor.

[0036] In this embodiment, the alternating pole asymmetric rotor of the novel rare-earth hybrid permanent magnet motor has one permanent magnet pole mainly composed of three permanent magnet embedding slots of different sizes: a first permanent magnet embedding slot 7, a second permanent magnet embedding slot 8, and a third permanent magnet embedding slot 9; a first permanent magnet 10 (rare-earth permanent magnet material), a second permanent magnet 11 (non-rare-earth permanent magnet material), and a third permanent magnet 12 (non-rare-earth permanent magnet material); and a first non-permanent magnet slot with arbitrary number, position, shape, and size for adjusting motor performance. 24, slot 25, slot 3, slot 4, slot 5, slot 6, slot 29, which are used for magnetic isolation and to ensure mechanical strength, and are composed of magnetic bridge 19, magnetic bridge 20, magnetic bridge 21, and variable magnetic bridge between permanent magnets 1 and 22, and magnetic bridge 23 between permanent magnets 2 and 3.

[0037] In this embodiment, the magnetization direction of the first permanent magnet 10, the second permanent magnet 11, and the third permanent magnet 12 of each permanent magnet pole in the alternating pole asymmetric rotor are perpendicular to the long side 16 of the first permanent magnet, the long side 17 of the second permanent magnet, and the long side 18 of the third permanent magnet, respectively, and simultaneously point towards the direction closer to the air gap or away from the air gap. The combined magnetization direction of each pole, with the positive radial direction as a reference, presents either an N pole or an S pole to the entire motor, unlike in traditional motors where the combined magnetization direction of adjacent poles is always an alternating N and S pole arrangement. This determines that the number of permanent magnet poles in the alternating pole rotor is equal to the number of pole pairs, whereas in traditional motors, the number of permanent magnet poles is equal to twice the number of pole pairs.

[0038] In this embodiment, the alternating pole asymmetric rotor of the novel rare earth hybrid permanent magnet motor is assembled with the shaft through the rotor shaft hole 4. The assembly can be carried out through the keyway 6 or the convex key 5.

[0039] In this embodiment, ventilation and weight reduction holes 33 can be opened at different positions on the rotor core 3 as needed. The number, size, shape, and position of the holes can be determined as needed.

[0040] The key feature of the alternating pole asymmetric rotor of the novel rare-earth hybrid permanent magnet motor in this embodiment is:

[0041] 1. The asymmetry in the distribution and size of the permanent magnets and permanent magnet embedding slots on both sides of the magnetic pole center line 34. The permanent magnet embedding slots can be designed as needed, and the form is not limited.

[0042] 2. Both permanent magnets made of rare-earth permanent magnet materials and permanent magnets made of non-rare-earth permanent magnet materials were used.

[0043] This embodiment of the novel rare-earth hybrid permanent magnet motor improves torque density by employing an alternating pole asymmetric rotor, based on the magnetic field offset effect. The specific principle is as follows:

[0044] according to Figure 4 (a) The flux linkage of a symmetrical rotor permanent magnet synchronous motor in the dq coordinate system can be expressed as:

[0045]

[0046] In the formula: ψ d and ψ q These are the d-axis flux linkage and the q-axis flux linkage, respectively. ψ PM This represents the amplitude of the permanent magnet flux linkage. i s For stator current, L d and L q These are the d-axis inductance and the q-axis inductance, respectively. β This is the current lead angle.

[0047] After the rotor becomes asymmetrical, according to Figure 4 (b) The flux linkage of the permanent magnet synchronous motor in the dq coordinate system can be expressed as:

[0048]

[0049] In the formula: α s This is the magnetic field offset angle caused by rotor asymmetry.

[0050] Therefore, the torque component of a symmetrical rotor permanent magnet synchronous motor can be written as:

[0051]

[0052] In the formula: T m For permanent magnet torque, T r For reluctance torque, p It is an extreme logarithm.

[0053] The torque component of an asymmetrical rotor permanent magnet synchronous motor can be written as:

[0054]

[0055] The combined torque of a symmetrical rotor and an asymmetrical rotor permanent magnet synchronous motor can be written as:

[0056]

[0057] In the formula: T e1 and T e2These are the combined torques of a symmetrical rotor permanent magnet synchronous motor and an asymmetrical rotor permanent magnet synchronous motor, respectively. T PM and T rel These represent the amplitudes of the permanent magnet torque and the reluctance torque, respectively.

[0058] Figure 5 To illustrate the torque-current lead angle characteristics of symmetrical rotor permanent magnet synchronous motors and asymmetrical rotor permanent magnet synchronous motors derived from the above formula, Δ in the figure... β 1 and Δ β 2 represents the difference in current lead angle between the maximum permanent magnet torque and the maximum reluctance torque in a symmetrical rotor permanent magnet synchronous motor and an asymmetrical rotor permanent magnet synchronous motor, respectively. Figure 5 It can be seen that after the rotor adopts an asymmetrical structure, the current lead angle between the maximum permanent magnet torque and the maximum reluctance torque is reduced. α s The maximum combined torque was increased without changing the amount of permanent magnets used.

[0059] In the rotor of a permanent magnet synchronous motor, since the magnetic properties of non-rare earth permanent magnets are weaker than those of rare earth permanent magnets, replacing some of the rare earth permanent magnets with non-rare earth permanent magnets will cause a decrease in the output performance of the motor. However, the magnetic field offset effect generated by the asymmetrical rotor can compensate for the loss of output performance. This is the key reason why the novel low-rare earth hybrid permanent magnet motor of this invention can effectively reduce costs while ensuring the output performance of the motor.

[0060] Figure 6 A design example of a rare-earth hybrid permanent magnet motor that meets the requirements of this invention is presented. It has three pole pairs. As shown in its armature open-circuit magnetic field distribution diagram, although this example has only three permanent magnet poles, the alternating pole structure generates a six-pole magnetic field within the motor air gap, which is the same as the traditional non-alternating pole structure. Simultaneously, the asymmetrical rotor causes the magnetic field lines of the permanent magnet poles to be asymmetrically distributed along the pole centerline, producing a significant magnetic field offset effect.

[0061] In this invention, other parts of the rotor structure, such as the absence of permanent magnet slots, ventilation and weight-reduction holes, and the shape of rotor assembly holes, can be modified as needed and are not subject to constraints. The rotor is the focus of this invention; the stator and winding structures are not within the scope of constraints and can be modified according to requirements in practical applications.

[0062] Example 2

[0063] Based on Embodiment 1, the rotor structure in this invention is not limited to an inner rotor structure with a radial magnetic circuit; outer rotors with a radial magnetic circuit, axial rotors, and other structures can also be used, resulting in various rotor structure forms. The permanent magnet material in this invention is not limited to non-rare-earth permanent magnets and rare-earth permanent magnets. In practical applications, the rotor can use any two or more different permanent magnet materials. This embodiment is a novel rare-earth hybrid permanent magnet outer rotor motor. The key to this invention is that the magnetic pole configuration within each pair of poles is completely identical, meaning that the permanent magnet characteristics within a pair of poles are completely identical after rotating a positive integer number of pole pairs along the positive circumferential direction. Each permanent magnet pole contains at least two or more permanent magnets of different sizes, the permanent magnets are asymmetrically distributed about any radial straight line, and the rotor contains at least two or more permanent magnets made of different permanent magnet materials. Figure 7 The structure of the extremely rare earth mixed permanent magnet alternating polar asymmetric outer rotor in this embodiment 6 is given. The outer rotor refers to the structure in which the inner diameter of the rotor is larger than the outer diameter of the stator, and the permanent magnet is still located on the moving outer rotor.

[0064] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. Those skilled in the art can readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. A novel rare-earth hybrid permanent magnet motor, characterized in that: An alternating pole asymmetrical rotor is employed, comprising a rotor core with a rotor shaft hole at its center. The rotor consists of multiple pairs of poles circumferentially, each pair consisting of a core pole and a permanent magnet pole. The rotor core serves as the core pole, replacing half of the magnetic poles. The permanent magnet poles are composed of permanent magnets of the same polarity but different sizes and materials, forming a magnetic pole structure where permanent magnet poles and core poles are alternately distributed around the rotor circumference. Each permanent magnet pole has a large and two small asymmetrical permanent magnet embedding slots. These slots contain permanent magnets of the same magnetization direction but different sizes and asymmetrical arrangement. The large slot contains rare-earth permanent magnets, while the two smaller slots contain non-rare-earth permanent magnets. Magnetic bridges are located at the ends of the permanent magnets near the air gap, and magnetic bridges are also present between the permanent magnets within the permanent magnet poles. The magnetic pole structure is V-shaped, with the center line of the magnetic poles bisecting the mechanical angle that each pair of poles crosses on the rotor circumference. Each permanent magnet pole has a first permanent magnet embedding slot, a second permanent magnet embedding slot, and a third permanent magnet embedding slot that are asymmetrically distributed about the center line of the magnetic pole. The first permanent magnet embedding slot spans both sides of the center line of the magnetic pole, while the second and third permanent magnet embedding slots are located on the same side of the center line of the magnetic pole. The first, second, and third permanent magnets are respectively embedded in the first, second, and third permanent magnet embedding slots. The magnetization directions of the first, second, and third permanent magnets are perpendicular to the long side of their respective permanent magnets and simultaneously point towards the air gap or away from the air gap.

2. The novel rare-earth hybrid permanent magnet motor according to claim 1, characterized in that: The first permanent magnet is a single-layer permanent magnet, the second permanent magnet and the third permanent magnet constitute a double-layer permanent magnet, and the first permanent magnet, the second permanent magnet and the third permanent magnet constitute a single-double-layer mixed magnetic pole.

3. The novel rare-earth hybrid permanent magnet motor according to claim 1, characterized in that: The first permanent magnet is made of rare earth permanent magnet material, while the second and third permanent magnets are made of non-rare earth permanent magnet material. The first, second, and third permanent magnets are all different in size, and the volume of the first permanent magnet is larger than that of the second and third permanent magnets. The first, second, and third permanent magnets constitute a hybrid permanent magnet material pole.

4. The novel rare-earth hybrid permanent magnet motor according to claim 1, characterized in that: The No. 1 permanent magnet embedding slot, the No. 2 permanent magnet embedding slot, and the No. 3 permanent magnet embedding slot are all provided with slots without permanent magnets.

5. The novel rare-earth hybrid permanent magnet motor according to claim 1, characterized in that: The first permanent magnet embedding slot, the second permanent magnet embedding slot, and the third permanent magnet embedding slot are all equipped with permanent magnet assembly slots.

6. The novel rare-earth hybrid permanent magnet motor according to claim 1, characterized in that: The rotor core is provided with ventilation and weight reduction holes evenly distributed along the circumference, and the ventilation and weight reduction holes are only arranged at the core pole position of each pair of poles.

7. The novel rare-earth hybrid permanent magnet motor according to claim 1, characterized in that: The rotor shaft hole is provided with a keyway and a key.

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