Motor rotor structure giving consideration to permanent magnet fixation and electromagnetic performance and design method thereof

Abstract

The invention discloses a motor rotor structure giving consideration to permanent magnet fixing and electromagnetic performance and a design method thereof. The rotor structure comprises a rotor yoke, bionic wedge-shaped rotor teeth integrally formed on the inner circumference of the rotor yoke and permanent magnets embedded between the teeth. The tooth side surfaces of the rotor are matched with the side surfaces of the permanent magnets, so that the radial and circumferential reliable mechanical constraint of the permanent magnets is realized, and the motor performance reduction and damage caused by the movement or falling of the permanent magnets under high acceleration can still be prevented when an adhesive fails; and the inverted V-shaped groove is formed in the middle of the tooth tip part, so that interelectrode flux leakage is effectively reduced, and the output torque of the motor is improved. Based on the constraint of the maximum impact acceleration and the safety coefficient on rotor structure parameters, the optimization design problem of the geometric shape of the rotor teeth is constructed and solved, and the narrowest position of the rotor teeth is magnetically saturated at a rated working point, so that the magnetic flux leakage path magnetic resistance is greatly increased, the magnetic flux leakage is reduced, and the electromagnetic output torque of the motor is maximized. The method is suitable for aerospace and other extreme mechanical environments, and realizes the optimal collaborative design of reliable fixation of the permanent magnet and electromagnetic performance of the motor.

Description

Technical Field

[0001] This invention relates to a motor rotor structure and its design method that balances permanent magnet fixation and electromagnetic performance, belonging to the field of motor technology. Background Technology

[0002] Permanent magnet motors are widely used in industrial and civilian fields due to their high efficiency and high power density. In special applications such as aerospace, for example, external rotor surface-mounted permanent magnet synchronous motors used in space solar panels must withstand extreme instantaneous high acceleration (>10g) overloads and complex and severe mechanical vibration environments during rocket launch. Under such multi-directional, high-intensity composite dynamic load impacts, if the permanent magnets are not securely fixed or the adhesive fails under extreme conditions such as high temperatures, displacement, loosening, or even detachment can easily occur. This can not only lead to a sharp decline in motor performance but, in severe cases, cause fatal system failures. Therefore, the fixing structure of the permanent magnets faces extremely high reliability requirements far exceeding those of conventional applications.

[0003] Because permanent magnet materials are inherently brittle, they cannot be simply fixed using an interference fit; additional mechanical structures are required for secure fixation. For example, a Chinese patent (CN119483020A, published on February 18, 2025) discloses a pole fixing and limiting structure for surface-mounted permanent magnet motors. When the motor rotates, the contact block, under centrifugal force, can fix the permanent magnet radially and axially. However, this structure has numerous parts and is complex, making it prone to metal fatigue fracture under high-intensity operation. Furthermore, the contact block only provides limiting pressure when the motor rotates; during rocket launches, when the motor is not running, this structure cannot provide effective fixation if the adhesive fails.

[0004] In addition, existing permanent magnet fixing solutions mostly focus on ensuring reliable fixing under high rotational speed and strong centrifugal force, without fully considering complex effects such as high acceleration due to rocket launch overshoot, transient high overload, and wide-frequency random vibration. They cannot provide reliable fixing of permanent magnets in all aspects while taking into account electromagnetic performance such as motor output torque. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a motor rotor structure and its design method that takes into account both permanent magnet fixation and electromagnetic performance, and provides reliable fixation of permanent magnet in all directions while taking into account electromagnetic performance such as motor output torque.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A motor rotor structure that balances permanent magnet fixation and electromagnetic performance includes: a rotor core and permanent magnets. The rotor core includes a rotor yoke and biomimetic wedge-shaped rotor teeth. The permanent magnets are uniformly arranged along the circumference, with the outer arc surface of the permanent magnets fitting against the inner surface of the rotor yoke. Biomimetic wedge-shaped rotor teeth protruding radially towards the permanent magnets are provided between adjacent permanent magnets. The two circumferential sides of each permanent magnet contact or are fitted with the corresponding sides of their adjacent biomimetic wedge-shaped rotor teeth through a gap. The biomimetic wedge-shaped rotor teeth are generally dovetail-shaped, with a rectangular root section and a chamfer at the junction of the root and the rotor yoke. The tooth tip is wedge-shaped, with a chamfer at the junction of the wedge and the rectangle. A ∧-shaped groove is formed in the middle of the tooth tip, and chamfers are provided at the apexes of both the wedge and the ∧-shaped groove. The rotor yoke and the biomimetic wedge-shaped rotor teeth are integrally formed. The permanent magnets are radially magnetized, with adjacent permanent magnets magnetized in opposite directions. The biomimetic wedge-shaped rotor teeth provide a purely mechanical locking mechanism for the permanent magnet without relying on auxiliary binders, achieving bidirectional mechanical constraint on the permanent magnet in both the circumferential and radial directions.

[0007] As a preferred embodiment of the present invention, the rotor structure further includes a permanent magnet front baffle and a permanent magnet rear baffle, both of which are annular, and are respectively disposed at the front and rear ends of the rotor core.

[0008] As a preferred embodiment of the present invention, for the outer rotor structure, both the front baffle and the rear baffle of the permanent magnet are connected to the motor housing by screws; for the inner rotor structure, both the front baffle and the rear baffle of the permanent magnet are connected to the motor shaft by screws or a keyway structure, in order to resist axial impact and prevent the permanent magnet from falling off axially.

[0009] As a preferred embodiment of the present invention, the permanent magnet is an arc-shaped block structure, the outer arc surface of the permanent magnet is a concentric circular arc surface adapted to the inner surface of the rotor yoke, the two sides of the permanent magnet facing the biomimetic wedge rotor teeth are curved surfaces and are symmetrically arranged, the root of the permanent magnet is provided with a chamfer adapted to the root of the biomimetic wedge rotor teeth, and the tip of the permanent magnet matches the wedge tip of the biomimetic wedge rotor teeth.

[0010] A permanent magnet synchronous motor includes a rotor structure and a stator structure that take into account both permanent magnet fixation and electromagnetic performance. The stator structure includes a stator core. The rotor core and the stator core are coaxially mounted. The rotor core is placed inside the stator core to form an inner rotor permanent magnet synchronous motor, or the rotor core is placed outside the stator core to form an outer rotor permanent magnet synchronous motor.

[0011] A design method is provided for designing a motor rotor structure that balances permanent magnet fixation and electromagnetic performance. The design method includes: determining the main dimensional parameters of the motor according to design requirements, including air gap length, permanent magnet thickness, pole arc coefficient, rotor yoke thickness, and stator structural parameters; adding a biomimetic wedge-shaped rotor tooth structure, using the dimensions of the biomimetic wedge-shaped rotor tooth structure as parameters to be optimized; constructing a sample set of rotor structure parameters to be optimized; and based on a surrogate model, establishing and solving an optimization problem that balances electromagnetic field and stress field performance objectives under mechanical strength constraints to determine the optimal geometric parameters of the rotor structure.

[0012] As a preferred embodiment of the present invention, the parameters to be optimized for the biomimetic wedge-shaped rotor teeth include: pole pitch. Polar arc The width at the junction of the root and tip of the biomimetic wedge-shaped rotor teeth The width at the widest point of the tooth tip minus The second half The angle between the plane where the tooth tip contacts the permanent magnet and the inner arc surface of the permanent magnet. Half the width of the ∧-shaped groove opening and the opening angle of the ∧-shaped groove .

[0013] As a preferred embodiment of the present invention, based on a surrogate model, an optimization problem that considers both electromagnetic field and stress field performance objectives is established and solved under the constraint of mechanical strength, thereby determining the optimal geometric parameters of the rotor structure, as follows: Finite element electromagnetic field and structural stress coupling simulations were performed on the motor rotor structure. Each sample from the sample set was input into a surrogate model, and genetic and neural network algorithms were used to calculate and determine the optimal geometric parameters of the rotor structure. The genetic algorithm was used to calculate the parameters to be optimized, while the neural network algorithm was used to accelerate the optimization process. The optimal geometric parameters satisfy the following conditions: the rotor tooth stress is less than the maximum stress that the material can withstand, and the rotor tooth strain is less than the critical value for permanent magnet detachment. Under these constraints, an optimization design that minimizes inter-pole leakage flux was performed to achieve the comprehensive optimization of the motor's mechanical reliability and electromagnetic performance.

[0014] As a preferred embodiment of the present invention, during the calculation process using genetic algorithms and neural network algorithms, the maximum instantaneous acceleration experienced by the motor is considered. and preset safety factor The equivalent acceleration required for the biomimetic wedge-shaped rotor teeth was calculated. This allows for the determination of the minimum required to prevent permanent magnet detachment due to strain in the biomimetic wedge-shaped rotor teeth. ; In the smallest Under the constraints, electromagnetic performance is optimized by increasing the magnetic path length of the inter-pole leakage magnetic path and minimizing the cross-sectional area of ​​the rotor teeth perpendicular to the leakage magnetic direction. This makes the biomimetic wedge-shaped rotor teeth more prone to magnetic saturation, resulting in the motor with optimal electromagnetic performance. .

[0015] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects: 1. This invention innovatively sets an integrated biomimetic wedge-shaped rotor tooth on the rotor core body, which achieves radial and circumferential dual locking of the external rotor surface-mounted permanent magnet under extreme dynamic loads in an extremely simple, robust and reliable purely mechanical way. This ensures that there is no risk of permanent magnet falling off in the permanent magnet motor under extreme mechanical environments such as aerospace, thereby improving the reliability of the motor structure.

[0016] 2. The rotor structure designed in this invention eliminates the need for external binding, protective sleeves and other additional parts. While significantly improving the system's resistance to centrifugal force, impact and vibration, it maintains the rotor's compact structure and lightweight design, which is particularly suitable for the extreme requirements of motor performance and reliability in high-reliability application fields such as aerospace.

[0017] 3. This invention effectively reduces inter-pole magnetic leakage of permanent magnets by carving ∧-shaped grooves at the tips of the biomimetic wedge-shaped rotor teeth, thus keeping the decline in the electromagnetic performance of the motor within an acceptable range. Attached Figure Description

[0018] Figure 1 This is an exploded view of the 3D structure of the motor designed in this invention; Figure 2 This is a 2D structural cross-sectional view of the motor designed in this invention; Figure 3 This invention relates to the biomimetic wedge-shaped rotor tooth structure. Figure 4 This is a flowchart of the rotor structure design method of the present invention that takes into account both reliable fixation of permanent magnets and electromagnetic performance of motor. Figure 5 The rotor structure stress cloud diagram is obtained by the rotor structure design method of the present invention, which takes into account both the reliable fixation of permanent magnets and the electromagnetic performance of motors. Figure 6 This is a comparison chart of the output torque of a conventional surface-mount motor and a motor with biomimetic wedge-shaped rotor teeth. Figure 7 This is a partial schematic diagram of the biomimetic wedge-shaped rotor teeth of the inner rotor.

[0019] In the figure, 1-permanent magnet front baffle, 2-permanent magnet rear baffle, 3-rotor core, 31-bionic wedge rotor teeth, 32-rotor yoke, 33-∧-shaped slot, 4-permanent magnet, 5-stator core, 6-winding. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] This invention proposes a motor rotor structure that balances permanent magnet fixation and electromagnetic performance. On the one hand, it ensures that the permanent magnet motor does not have the risk of permanent magnet detachment in extreme mechanical environments such as aerospace, thereby improving the reliability of the motor structure. On the other hand, by carving ∧-shaped grooves at the tips of the biomimetic wedge-shaped rotor teeth, it effectively reduces the inter-pole leakage flux of the permanent magnet, thereby improving the electromagnetic performance and power density of the motor.

[0022] The rotor structure, which balances reliable permanent magnet fixation with the electromagnetic performance of the motor, features a biomimetic wedge-shaped rotor tooth protruding radially from the permanent magnet side, integrally formed or fixedly installed on the surface of the rotor core between two circumferentially adjacent permanent magnets. The root of this rotor tooth has a rectangular cross-section, with a chamfer at the junction of the tooth root and the rotor yoke to prevent stress concentration. The tooth tip is wedge-shaped, with a chamfer at the junction of the wedge and the rectangle. A ∧-shaped groove is carved in the middle of the tooth tip, and chamfering is applied to all junctions, ultimately forming a dovetail-like biomimetic wedge-shaped rotor tooth.

[0023] In the assembled state, permanent magnets are embedded into adjacent biomimetic wedge-shaped rotor teeth. The outer arc surface of the permanent magnet fits against the inner surface of the rotor core's base circle, while its two sides are in close contact with or fitted with the two sides of the biomimetic wedge-shaped rotor teeth through a very small clearance. The root shape of the permanent magnet is also designed with chamfers according to the rotor core structure. This geometric structure achieves bidirectional mechanical constraint on the two adjacent permanent magnets in both the circumferential and radial directions. In addition, the permanent magnet baffles at the front and rear ends effectively prevent the permanent magnets from axially falling off.

[0024] The permanent magnet has an arc-shaped block structure. The outer arc surface of the permanent magnet is a concentric arc surface that matches the inner surface of the rotor yoke. The two sides of the permanent magnet facing the biomimetic wedge rotor teeth are curved and symmetrically arranged. The root of the permanent magnet has a chamfer that matches the root of the biomimetic wedge rotor teeth. The tip of the permanent magnet matches the wedge tip of the biomimetic wedge rotor teeth.

[0025] The biomimetic wedge-shaped rotor teeth provide the permanent magnet with a primary, purely mechanical locking mechanism that does not rely on auxiliary adhesives. Even if the space environment causes the adhesive between the permanent magnet and the base circle of the rotor core to degrade or fail, the tight fit between the integrated biomimetic wedge-shaped rotor teeth on the rotor core and the side of the permanent magnet can independently and reliably prevent the permanent magnet from falling off in any direction, achieving an inherently fail-safe design.

[0026] When the gap between permanent magnets is small, there will be a low magnetic resistance inter-pole leakage magnetic path between the permanent magnets. This causes the magnetic flux to bypass the air gap and link with the stator winding to do work, and instead directly short-circuit through the rotor teeth. This inter-pole leakage magnetic field will weaken the effective air gap magnetic flux density of the motor, which will lead to a decrease in the motor's torque output capability, power density and efficiency.

[0027] Therefore, the present invention provides a method for the coordinated design of geometric parameters for the biomimetic wedge-shaped rotor teeth, so as to minimize the leakage flux between permanent magnets and optimize the electromagnetic performance of the motor under the primary premise of ensuring that the permanent magnets are absolutely reliable (i.e., do not fall off) under extreme mechanical conditions.

[0028] Figure 3 The biomimetic wedge-shaped rotor tooth structure designed in this invention has a root portion that is in close contact with the side of the permanent magnet, and the width at the junction of the root and tip of the biomimetic wedge-shaped rotor tooth is [missing information]. The angle between the plane where the tooth tip contacts the permanent magnet and the inner arc surface of the permanent magnet is... The width at the widest point of the tooth tip minus The second half is Half the width of the ∧-shaped groove opening is The opening angle of the ∧-shaped groove is , For polar distance, The hollowed-out section effectively reduces inter-pole magnetic leakage of the permanent magnet, ensuring the electromagnetic performance of the motor.

[0029] like Figure 4 As shown, this invention also proposes a design method for a motor rotor structure that balances permanent magnet fixation and electromagnetic performance. First, based on the maximum instantaneous acceleration... and safety factor The acceleration required for the biomimetic wedge-shaped rotor teeth is obtained. Calculate the minimum structural dimensions required to prevent the biomimetic wedge-shaped rotor teeth from falling off the permanent magnet. Based on this, electromagnetic optimization aimed at maximizing reluctance is performed: by increasing the magnetic circuit length of the leakage flux path and minimizing the cross-sectional area of ​​the rotor teeth perpendicular to the leakage flux direction while ensuring mechanical strength, the rotor teeth are made more prone to magnetic saturation, resulting in structural dimensions that ensure optimal electromagnetic performance of the motor. Finally, through finite element electromagnetic field and structural stress coupling simulation, using a surrogate model, and through calculation using genetic algorithm or neural network algorithm, a set of optimal geometric parameters is determined. This ensures that the biomimetic wedge rotor teeth reliably fix the permanent magnet and that the rotor tooth stress is less than the maximum stress that the material can withstand, while minimizing inter-pole leakage flux, thus optimizing the electromagnetic performance of the motor and achieving the best balance between reliability and electromagnetic performance.

[0030] Finite element coupled simulation is used to simultaneously verify the structural stress strength of the rotor teeth and the electromagnetic performance of the motor, so as to maximize the electromagnetic performance of the motor while satisfying the structural strength constraints.

[0031] The core objective of electromagnetic optimization is to maximize the magnetic reluctance of the inter-pole leakage magnetic path, thereby reducing the impact of inter-pole leakage magnetic field on the effective air gap magnetic flux density of the motor and ensuring the motor's torque output capability and power density.

[0032] The present invention will now be described in detail using an external rotor embodiment.

[0033] Figure 1 and Figure 2 The exploded 3D view and sectional 2D view of the motor structure designed based on the rotor structure of this invention are shown below. The motor includes: a permanent magnet front baffle 1, a permanent magnet rear baffle 2, a rotor core 3, biomimetic wedge-shaped rotor teeth 31, a rotor yoke 32, permanent magnets 4, a stator core 5, and windings 6. The stator structure adopts a 24-slot design, with 24 teeth in the circumferential direction. The rotor structure adopts a 26-pole design, with one rotor yoke and 26 biomimetic wedge-shaped rotor teeth inside. A ∧-shaped groove 33 is carved out in the middle of the tooth tip. The permanent magnets are magnetically charged radially, with adjacent permanent magnets charging in opposite directions.

[0034] Even in the worst-case scenario where the adhesive completely fails, the biomimetic wedge-shaped rotor teeth 31, the front baffle 1 of the permanent magnet, and the rear baffle 2 of the permanent magnet can still reliably protect the permanent magnet from detachment. Regarding radial fixation, the inclined surfaces of the biomimetic wedge-shaped rotor teeth constitute a radial support surface for the permanent magnet. For example... Figure 2 and Figure 3 When the motor is subjected to a strong y-direction impact during launch, the outward force on the permanent magnet is transmitted to the inclined surface of the rotor teeth. Due to the geometric characteristics of the dovetail structure, this radial force is decomposed and transformed into stronger tensile stress on the rotor teeth themselves and greater normal pressure between the permanent magnet and the inclined surface of the rotor teeth, thereby mechanically preventing the permanent magnet from radially dislodging from the rotor surface. Simultaneously, the two sides of the biomimetic wedge-shaped rotor teeth form a direct, surface-contact x-direction constraint on the two adjacent permanent magnets. This structure effectively resists the x-direction impact experienced by the motor during launch, as well as the tangential forces and torques generated during speed changes, load abrupt changes, and severe vibrations, preventing circumferential movement or rotation of the permanent magnet and ensuring the accuracy and stability of the motor's magnetic pole position.

[0035] In addition, the permanent magnet front baffle 1 and the permanent magnet rear baffle 2 are connected to the housing by screws. When the motor is subjected to a strong z-direction (axial) impact, the baffle can effectively protect the permanent magnet and prevent it from falling off axially.

[0036] Figure 5 The rotor structure stress cloud diagram obtained by the rotor structure design method of this invention, which balances reliable permanent magnet fixation and motor electromagnetic performance, is obtained by taking the maximum instantaneous acceleration. and safety factor .like Figure 5 As shown, the maximum stress occurs at point A. After verification, the maximum stress of the structure is less than the yield strength of the selected material, and its strain is less than the critical strain value under this working condition, which can ensure the reliable fixation of the permanent magnet.

[0037] Figure 6 The graph compares the output torque of a conventional surface-mount motor (without biomimetic wedge-shaped rotor teeth, no permanent magnet fixing structure) and the present invention's motor with biomimetic wedge-shaped rotor teeth (with a reliable permanent magnet fixing structure). Under the same current density, the output torque of the conventional surface-mount motor is... The output torque of the biomimetic wedge-shaped rotor tooth motor is Compared to conventional surface-mount motors without a permanent magnet fixing structure, the torque decreases by only 4.7% after adding biomimetic wedge-shaped rotor teeth. This shows that by adding biomimetic wedge-shaped rotor teeth, the permanent magnet of the motor is reliably fixed, and the electromagnetic performance is not significantly reduced, achieving a balance between reliable permanent magnet fixing and electromagnetic performance.

[0038] Figure 7 The internal rotor features a biomimetic wedge-shaped rotor tooth structure. For internal rotor motors, the same method can be used to design biomimetic wedge-shaped rotor teeth, which can effectively prevent permanent magnets from falling off under harsh conditions such as high acceleration, wide-frequency random vibration, and high-speed rotation.

[0039] Compared to existing conventional solutions, the rotor structure and its design method of the present invention, which takes into account both reliable fixation of permanent magnets and electromagnetic performance, can still provide reliable fixation of permanent magnets in all aspects even under the harsh condition of complete failure of permanent magnet glue. At the same time, by optimizing the design of the biomimetic wedge rotor tooth structure, the degradation of electromagnetic performance can be greatly reduced, achieving the best synergistic design of mechanical reliability and electromagnetic performance.

[0040] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A motor rotor structure that balances permanent magnet fixation and electromagnetic performance, characterized in that, include: The rotor core comprises a rotor yoke and biomimetic wedge-shaped rotor teeth. The permanent magnets are uniformly arranged circumferentially, with their outer arc surfaces fitting against the inner surface of the rotor yoke. Between adjacent permanent magnets, biomimetic wedge-shaped rotor teeth protrude radially towards the permanent magnet side. Each permanent magnet has two circumferentially adjacent sides that contact or are fitted with the corresponding sides of its adjacent biomimetic wedge-shaped rotor teeth through a gap. The biomimetic wedge-shaped rotor teeth are generally dovetail-shaped, with a rectangular root section and a chamfer at the junction of the root and the rotor yoke. The tip is wedge-shaped, with a chamfer at the junction of the wedge and the rectangle. A ∧-shaped groove is formed in the middle of the tip, and chamfers are provided at the apexes of both the wedge and the ∧-shaped groove. The rotor yoke and the biomimetic wedge-shaped rotor teeth are integrally formed. The permanent magnets are radially magnetized, with adjacent permanent magnets magnetized in opposite directions. The biomimetic wedge-shaped rotor teeth provide a purely mechanical locking mechanism for the permanent magnet without relying on auxiliary binders, achieving bidirectional mechanical constraint on the permanent magnet in both the circumferential and radial directions.

2. The motor rotor structure that combines permanent magnet fixation and electromagnetic performance according to claim 1, characterized in that, The rotor structure also includes a permanent magnet front baffle and a permanent magnet rear baffle, both of which are annular and are respectively located at the front and rear ends of the rotor core.

3. The motor rotor structure that combines permanent magnet fixation and electromagnetic performance according to claim 2, characterized in that, For the external rotor structure, both the front and rear baffles of the permanent magnet are connected to the motor housing by screws; for the internal rotor structure, both the front and rear baffles of the permanent magnet are connected to the motor shaft by screws or keyways to resist axial impact and prevent the permanent magnet from falling off axially.

4. The motor rotor structure that combines permanent magnet fixation and electromagnetic performance according to claim 1, characterized in that, The permanent magnet has an arc-shaped block structure. The outer arc surface of the permanent magnet is a concentric arc surface that matches the inner surface of the rotor yoke. The two sides of the permanent magnet facing the bionic wedge rotor teeth are curved surfaces and are symmetrically arranged. The root of the permanent magnet has a chamfer that matches the root of the bionic wedge rotor teeth. The tip of the permanent magnet matches the wedge tip of the bionic wedge rotor teeth.

5. A permanent magnet synchronous motor, characterized in that, The motor rotor structure and stator structure, which combine permanent magnet fixation and electromagnetic performance as described in any one of claims 1 to 4, are included. The stator structure includes a stator core. The rotor core and the stator core are coaxially mounted. The rotor core is placed inside the stator core to form an inner rotor permanent magnet synchronous motor, or the rotor core is placed outside the stator core to form an outer rotor permanent magnet synchronous motor.

6. A design method, characterized in that, The design method for designing a motor rotor structure that balances permanent magnet fixation and electromagnetic performance as described in any one of claims 1 to 4 includes: determining the main dimensional parameters of the motor according to design requirements, including air gap length, permanent magnet thickness, pole arc coefficient, rotor yoke thickness, and stator structural parameters; adding a biomimetic wedge-shaped rotor tooth structure, using the dimensions of the biomimetic wedge-shaped rotor tooth structure as parameters to be optimized; constructing a sample set of rotor structure parameters to be optimized; and, based on a surrogate model, establishing and solving an optimization problem that balances electromagnetic field and stress field performance objectives under mechanical strength constraints to determine the optimal geometric parameters of the rotor structure.

7. The design method according to claim 6, characterized in that, The parameters to be optimized for the biomimetic wedge-shaped rotor teeth include: pole pitch. Polar arc The width at the junction of the root and tip of the biomimetic wedge-shaped rotor teeth The width at the widest point of the tooth tip minus The second half The angle between the plane where the tooth tip contacts the permanent magnet and the inner arc surface of the permanent magnet. Half the width of the ∧-shaped groove opening and the opening angle of the ∧-shaped groove .

8. The design method according to claim 7, characterized in that, Based on the surrogate model, under the constraint of mechanical strength, an optimization problem that considers both electromagnetic field and stress field performance objectives is established and solved to determine the optimal geometric parameters of the rotor structure, as follows: Finite element electromagnetic field and structural stress coupling simulations were performed on the motor rotor structure. Each sample from the sample set was input into a surrogate model, and genetic and neural network algorithms were used to calculate and determine the optimal geometric parameters of the rotor structure. The genetic algorithm was used to calculate the parameters to be optimized, while the neural network algorithm was used to accelerate the optimization process. The optimal geometric parameters satisfy the following conditions: the rotor tooth stress is less than the maximum stress that the material can withstand, and the rotor tooth strain is less than the critical value for permanent magnet detachment. Under these constraints, an optimization design that minimizes inter-pole leakage flux was performed to achieve the comprehensive optimization of the motor's mechanical reliability and electromagnetic performance.

9. The design method according to claim 8, characterized in that, During the calculation process using genetic algorithms and neural network algorithms, the maximum instantaneous acceleration experienced by the motor is considered. and preset safety factor The equivalent acceleration required for the biomimetic wedge-shaped rotor teeth was calculated. This allows for the determination of the minimum required to prevent permanent magnet detachment due to strain in the biomimetic wedge-shaped rotor teeth. ; In the smallest Under the constraints, electromagnetic performance is optimized by increasing the magnetic path length of the inter-pole leakage magnetic path and minimizing the cross-sectional area of ​​the rotor teeth perpendicular to the leakage magnetic direction. This makes the biomimetic wedge-shaped rotor teeth more prone to magnetic saturation, resulting in the motor with optimal electromagnetic performance. .

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