High-power-density axial flux permanent magnet motor

Abstract

The invention relates to the technical field of permanent magnet motors, in particular to a high-power-density axial flux permanent magnet motor which comprises a stator structure, a first rotor structure and a second rotor structure. The stator structure comprises a stator core, stator teeth are uniformly arranged on the two sides, close to the second rotor structure and the first rotor structure, of the annular side face of the stator core at intervals in the circumferential direction, and stator grooves are formed between the adjacent stator teeth; the first rotor structure comprises a rotor core, and permanent magnets are uniformly arranged in the rotor core along the circumferential direction; the permanent magnets comprise insertion layer permanent magnets and surface-mounted layer permanent magnets, the insertion layer permanent magnets are embedded in the grooves of the rotor iron core, and the insertion layer permanent magnets and the surface-mounted layer permanent magnets are each divided into three sections in the radial direction. The thickness of the permanent magnets in the insertion layer and the pole-arc coefficient of the permanent magnets in each layer and each section can be optimized to improve the motor performance, the motor size is smaller, the utilization rate of the permanent magnets is high, and the power density is large.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet motors, and in particular to a high power density axial flux permanent magnet motor. Background Art

[0002] In the field of modern motor technology, with the growing demand for high power density motors, how to achieve higher power output under limited volume or weight has become a challenge to be solved. High power density motors have become the core technology in many application fields by providing more power in the same space, especially in space-constrained application scenarios, such as electric vehicles, aerospace, and consumer electronics. These fields have extremely high requirements for the volume and performance of motors. Therefore, how to improve the power density of motors has become an important issue in modern motor design. Among the many types of motors, the dual-rotor single-stator axial flux motor has attracted increasing attention due to its excellent power density performance. Compared with traditional motors, the dual-rotor single-stator axial flux motor can use the magnetic field more efficiently, thereby providing stronger power output. Its unique dual-rotor structure makes the motor more flexible in spatial layout and can achieve a more compact design. This design advantage enables the dual-rotor single-stator axial flux motor to integrate more functions in a limited space, especially for applications with strict requirements on volume and power density, such as drive systems in electric vehicles, propulsion systems in the aerospace field, and electric drive modules in high-performance consumer electronics.

[0003] In order to further improve the power density of the motor, it is crucial to optimize the structure and design of the motor. Especially in terms of axial length, the optimized design can significantly reduce the size of the motor, improve the power density and reduce the production cost. At present, common optimization methods include reducing the thickness of the rotor core and the thickness of the permanent magnet to reduce the axial length of the motor. However, these methods face certain challenges in practical applications: if the thickness of the rotor core is too thin, the utilization rate of the permanent magnet will decrease, reducing the magnetic energy conversion efficiency of the motor; and if the thickness of the permanent magnet is too small, it may affect the overall efficiency and operating stability of the motor. Therefore, how to optimize the structure of the rotor core and the permanent magnet while ensuring the efficiency and stability of the motor has become a key issue in improving the power density of the motor.

[0004] At present, the research on the optimization of the rotor of the dual-rotor single-stator axial flux permanent magnet motor is still insufficient, especially in the aspects of axial space optimization, efficient utilization of permanent magnets and rotor core surface design, there is still a huge room for improvement. In order to solve this problem, the existing technology has not fully explored how to achieve more refined axial optimization in the dual-rotor structure to improve the utilization efficiency of permanent magnets and ensure that the design of the rotor core meets the performance requirements of high power density motors.

[0005] In summary, the present application proposes a high power density axial flux permanent magnet motor to solve the above-mentioned problems. Summary of the invention

[0006] The present invention aims to solve the problems raised in the background technology. This specification provides a high power density axial flux permanent magnet motor, which can reduce the motor volume, improve the motor power density, increase the output torque, and suppress torque pulsation.

[0007] Based on the above purpose, the present invention provides a high power density axial flux permanent magnet motor, comprising a stator structure, a first rotor structure and a second rotor structure, wherein the second rotor structure, the stator structure and the first rotor structure are stacked in sequence and are at equal distances from the first rotor structure and the second rotor structure;

[0008] The stator structure comprises a stator core, stator teeth are evenly spaced along the circumferential direction on both sides of the annular side surface of the stator core close to the first rotor structure and close to the second rotor structure, stator slots are formed between adjacent stator teeth, and armature windings are embedded in the stator slots along the circumferential direction;

[0009] The first rotor structure and the second rotor structure are identical and symmetrical with respect to the central plane of the stator structure;

[0010] The first rotor structure comprises a rotor core, and permanent magnets are evenly arranged in the circumferential direction inside the rotor core.

[0011] Preferably, the permanent magnet comprises an insertion layer permanent magnet and a surface layer permanent magnet, wherein the insertion layer permanent magnet is embedded in the groove of the rotor core and has a thickness of T pm1 The surface-mounted permanent magnet is pasted on the surface of the rotor core with a thickness of T pm2 .

[0012] Preferably, the insertion layer permanent magnet and the surface layer permanent magnet are divided into three sections along the radial direction, the inner and outer radii of the outermost section permanent magnet are R1 and R2 respectively, the inner and outer radii of the middle section permanent magnet are R2 and R3 respectively, and the inner and outer radii of the innermost section permanent magnet are R3 and R4 respectively, and the width of each section is equal.

[0013] Preferably, the outermost permanent magnet pole arc coefficients of the insertion layer permanent magnet and the surface layer permanent magnet are α i1 , α s1 , the pole arc coefficients of the middle section permanent magnets are α i2 , α s2 , the innermost permanent magnet pole arc coefficients are α i3 , α s3 .

[0014] Preferably, the stator core, rotor core and stator teeth are all made of silicon steel material.

[0015] Preferably, the permanent magnet material is any one of neodymium iron boron, samarium cobalt and ferrite.

[0016] According to the above, the present invention has the following beneficial effects:

[0017] 1. The present invention adopts a dual-rotor single-stator structure, utilizes the principle that the output torque of the axial flux permanent magnet motor is independent of the axial length, and adopts a semi-inserted permanent magnet structure. The axial length of the motor can be optimized by optimizing the insertion depth of the permanent magnet, thereby reducing the size of the motor and improving the power density of the motor.

[0018] 2. The present invention divides the permanent magnets into three sections along the radial direction on the dual-rotor single-stator axial flux motor, and optimizes the design of the amount of permanent magnets in each section, which can reduce the torque pulsation of the output torque and improve the stability of the motor.

[0019] 3. The present invention adopts different pole arc coefficients for each layer and each section of permanent magnets, and can improve the output torque of the motor by optimizing the pole arc coefficients of the inserted layer permanent magnets and the surface mounted layer permanent magnets, thereby improving the utilization rate of the permanent magnets and reducing the cost of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate one or more embodiments of the present specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only one or more embodiments of the present specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A three-dimensional structural diagram of a specific embodiment of the present invention;

[0022] Figure 2 It is an exploded view of the three-dimensional structure of the present invention;

[0023] Figure 3 is a structural diagram of a second rotor of the present invention;

[0024] Figure 4 The rotor core diagram of the present invention;

[0025] Figure 5 A permanent magnet diagram of the present invention;

[0026] Figure 6 A volume comparison diagram of the motor of the present invention and a conventional motor;

[0027] Figure 7 The figure is a comparison of the air gap flux density of the motor of the present invention and the conventional motor under the same amount of permanent magnets;

[0028] Figure 8 This is a comparison diagram of the no-load back electromotive force of the motor of the present invention and the traditional motor under the same amount of permanent magnets;

[0029] Fig. 9 The figure is a torque comparison diagram of the motor of the present invention and the traditional motor under the same permanent magnet dosage.

[0030] Reference numerals:

[0031] 1. Stator structure; 2. First rotor structure; 3. Second rotor structure; 4. Stator core; 5. Stator teeth; 6. Stator slots; 7. Armature winding; 8. Permanent magnet; 9. Rotor core; 10. Insertion layer permanent magnet; 11. Surface mount layer permanent magnet. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments.

[0033] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a high power density axial flux permanent magnet motor, comprising a stator structure 1, a first rotor structure 2 and a second rotor structure 3, wherein the second rotor structure 3, the stator structure 1 and the first rotor structure 2 are stacked in sequence, and the second rotor structure 3 is at an equal distance from the first rotor structure 2 and the second rotor structure 3;

[0034] The stator structure 1 includes a stator core 4, and stator teeth 5 are evenly spaced along the circumferential direction on both sides of the annular side surface of the stator core 4 close to the second rotor structure 3 and the first rotor structure 2, and stator slots 6 are formed between adjacent stator teeth 5. Armature windings 7 are embedded in the stator slots 6, and currents in the same direction are passed through the armature windings 7 in symmetrical upper and lower slots; as a preferred embodiment, the number of stator slots 6 on the upper and lower sides of the stator core 4 is , and the number of stator teeth 5 is 45.

[0035] The first rotor structure 2 is identical to the second rotor structure 3 and is symmetrical with respect to the central plane of the stator structure 1. The first rotor structure 2 includes a rotor core 9, and permanent magnets 8 are evenly arranged circumferentially inside the rotor core 9. As a preferred embodiment, the number of poles of the permanent magnets 8 of the first rotor structure 2 and the second rotor structure 3 are both 10.

[0036] like Figure 3 As shown, the permanent magnet 8 includes an insertion layer permanent magnet 10 and a surface-mounted layer permanent magnet 11, wherein the insertion layer permanent magnet 10 is embedded in the groove of the rotor core 9 and has a thickness of T pm1 The surface-mounted permanent magnet 11 is pasted on the surface of the rotor core 9, and the thickness is T pm2 When optimizing the motor, T pm1 and T pm2Optimize to reduce the motor axial length and select the T with the best motor power density. pm1 and T pm2 value.

[0037] The permanent magnet 8 is divided into three sections along the radial direction. The inner and outer radii of the outermost section of the permanent magnet 8 are R1 and R2 respectively, the inner and outer radii of the middle section of the permanent magnet 8 are R2 and R3 respectively, and the inner and outer radii of the innermost section of the permanent magnet 8 are R3 and R4 respectively. The width of each section is equal, that is, R1-R2=R2-R3=R3-R4.

[0038] like Figure 4 and Figure 5 As shown, the surface shape of the rotor core 9 near the stator side is complementary to the insertion layer of the permanent magnet 8. The pole arc coefficients of the outermost permanent magnet 8 of the insertion layer permanent magnet 10 and the surface layer permanent magnet 11 are α i1 , α s1 , the arc coefficients of the 8-pole permanent magnets in the middle section are α i2 , α s2 , the innermost permanent magnet 8 pole arc coefficients are α i3 , α s3 , the pole arc coefficient of each permanent magnet 8 can be optimized.

[0039] The optimization range is: α i1 =0-1,,,α s1 =0-1,,,α i2 =0-1,,,α s2 =0-1,,α i3 =0-1,,α s3 =0-1.

[0040] like Figure 6 is a volume comparison diagram of the motor of this embodiment and the traditional motor. When the stator structure 1 is the same, the insertion depth T of the permanent magnet 8 is optimized. pm1 Compared with traditional motors, the axial length is reduced by 2T pm1 .

[0041] like Figure 7 : is a comparison diagram of the air gap flux density of the motor of this embodiment and the traditional motor. Under the same amount of permanent magnets 8, the air gap flux density waveform of the motor of this embodiment is more sinusoidal, the air gap flux density width generated by each pole is wider, and the utilization rate of the permanent magnets 8 is higher.

[0042] like Figure 8 : is a comparison diagram of the no-load back electromotive force of phase A of the motor of this embodiment and the conventional motor. Under the same amount of permanent magnet 8, the effective values ​​of the no-load back electromotive force of phase A of the conventional motor and the motor of this embodiment are 246V and 267V respectively. Not only is the effective value of the no-load back electromotive force of the motor of this embodiment higher, but the back electromotive force waveform is more sinusoidal.

[0043] like Fig. 9 This is a torque comparison chart between the motor of this embodiment and the conventional motor. Under the same amount of permanent magnet 8, the average output torque of the conventional motor is 138.2Nm, and the torque pulsation is 22.6%; the average output torque of the motor of this embodiment is 148.4Nm, and the torque pulsation is 5.9%. It can be seen that the motor of this embodiment has higher output torque and lower torque pulsation.

[0044] The stator core 4, the rotor core 9 and the stator teeth 5 are all made of silicon steel material, the permanent magnet 8 is made of any one of neodymium iron boron, samarium cobalt and ferrite, and the armature winding 7 is arranged in an integer slot concentrated winding structure.

[0045] The present invention provides a high power density axial flux permanent magnet motor. Under the same amount of permanent magnet 8, compared with the conventional motor, the motor volume of the present embodiment is reduced by about 6.2%, the average torque is increased by 7.4%, the torque pulsation is reduced by 73.9%, and the power density is increased by 14.5%. The present invention can not only reduce the motor volume and improve the motor power density, but also improve the output torque, suppress the torque pulsation, and reduce the motor cost.

[0046] One or more embodiments of this specification are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of this disclosure.

Claims

1. A high power density axial flux permanent magnet motor, characterized in that: The invention comprises a stator structure (1), a first rotor structure (2) and a second rotor structure (3), wherein the second rotor structure (3), the stator structure (1) and the first rotor structure (2) are stacked in sequence and are at equal distances from the first rotor structure (2) and the second rotor structure (3); The stator structure (1) comprises a stator core (4), stator teeth (5) are evenly spaced along the circumferential direction on both sides of the annular side surface of the stator core (4) close to the second rotor structure (3) and close to the first rotor structure (2), stator slots (6) are formed between adjacent stator teeth (5), and armature windings (7) are embedded in the stator slots (6); The first rotor structure (2) and the second rotor structure (3) are identical and are symmetrical with respect to the central plane of the stator structure (1); The first rotor structure (2) comprises a rotor core (9), and permanent magnets (8) are evenly arranged in the circumferential direction inside the rotor core (9).

2. The high power density axial flux permanent magnet motor according to claim 1, characterized in that: The permanent magnet (8) comprises an insertion layer permanent magnet (10) and a surface layer permanent magnet (11), wherein the insertion layer permanent magnet (10) is embedded in the groove of the rotor core (9) and has a thickness of T pm1 The surface-mounted permanent magnet (11) is attached to the surface of the rotor core (9) and has a thickness of T pm2 .

3. The high power density axial flux permanent magnet motor according to claim 2, characterized in that: The insertion layer permanent magnet (10) and the surface layer permanent magnet (11) are both divided into three sections along the radial direction, the inner and outer radii of the outermost section permanent magnet (8) are R1 and R2 respectively, the inner and outer radii of the middle section permanent magnet (8) are R2 and R3 respectively, and the inner and outer radii of the innermost section permanent magnet (8) are R3 and R4 respectively.

4. The high power density axial flux permanent magnet motor according to claim 2, characterized in that: The outermost permanent magnet (8) of the insertion layer permanent magnet (10) and the surface layer permanent magnet (11) have pole arc coefficients of α i1 , α s1 , the pole arc coefficients of the middle section permanent magnet (8) are α i2 , α s2 , the pole arc coefficients of the innermost permanent magnet (8) are α i3 , α s3 .

5. The high power density axial flux permanent magnet motor according to claim 1, characterized in that: The stator core (4), the rotor core (9) and the stator teeth (5) are all made of silicon steel material.

6. The high power density axial flux permanent magnet motor according to claim 1, characterized in that: The material of the permanent magnet (8) is any one of neodymium iron boron, samarium cobalt and ferrite.

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