Permanent magnet arrangement structure of rotor permanent magnet synchronous motor and optimization method

Abstract

The invention relates to a permanent magnet arrangement structure of a rotor permanent magnet synchronous motor and an optimization method. The rotor comprises a rotor iron core; the plurality of permanent magnet grooves are uniformly distributed on the edge of the rotor iron core at intervals along the circumferential direction; the plurality of permanent magnets are correspondingly arranged in the permanent magnet grooves; wherein the geometric contour of each permanent magnet comprises a straight edge section and an arch section which is convexly arranged along the straight edge section towards the edge direction of the rotor iron core, and the magnetizing direction of each permanent magnet is perpendicular to the length extension direction of the permanent magnet. By improving the shape and arrangement mode of the permanent magnets and adopting the improved fruit fly genetic algorithm to optimize the permanent magnet parameters, the permanent magnet parameters enabling the rotor stress to be minimum are obtained, so that the stress generated by the rotor iron core during high-speed rotation is reduced, the stress concentration of the rotor iron core during operation of the high-speed permanent magnet synchronous motor is improved, and the stability of the high-speed permanent magnet synchronous motor is improved. And the rotor strength is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor design, and in particular to a permanent magnet arrangement structure and an optimization method for a rotor permanent magnet synchronous motor. Background Art

[0002] With the acceleration of global scientific and technological progress and the full realization of industrialization, the research progress of permanent magnet synchronous motors has also made great strides. High-speed permanent magnet synchronous motors have the advantages of small size, high power density, and high efficiency. They can be widely used in aerospace, oil and gas petrochemical, medical equipment, CNC machine tools and other fields. At the same time, the speed of permanent magnet synchronous motors has also been greatly improved. It can meet the requirements of higher and higher speeds and promote the development of high-speed machinery and processes.

[0003] In the design and actual application of permanent magnet synchronous motors used in high-speed conditions, the strength of the rotor is easily affected by the high speed of the permanent magnet motor. Due to the high speed characteristics of high-speed permanent magnet synchronous motors, the design of a whole magnetic pole may result in insufficient rotor strength. When the rotor rotates at high speed, it will be subjected to a large centrifugal force, which puts higher requirements on the strength and stability of the rotor. The traditional whole magnetic pole method cannot meet these requirements, resulting in the whole magnetic pole structure easily causing rotor vibration and stress concentration when rotating at high speed, thereby reducing the strength of the rotor. Summary of the invention

[0004] To this end, the present invention provides a permanent magnet arrangement structure and optimization method for a rotor permanent magnet synchronous motor. By improving the shape and arrangement of the permanent magnets and using an improved fruit fly genetic algorithm to optimize the permanent magnet parameters, the permanent magnet parameters that minimize the rotor stress are obtained, thereby reducing the stress generated by the rotor core during high-speed rotation, improving the stress concentration of the rotor core during operation of the high-speed permanent magnet synchronous motor, and achieving an increase in the rotor strength.

[0005] In order to solve the above technical problems, the present invention provides a permanent magnet arrangement structure of a rotor permanent magnet synchronous motor, comprising:

[0006] Rotor core;

[0007] A plurality of permanent magnet slots are evenly distributed at intervals along the circumferential direction on the edge of the rotor core;

[0008] A plurality of permanent magnets are correspondingly arranged in each of the permanent magnet slots;

[0009] The geometrical profile of the permanent magnet includes a straight edge segment and an arched segment protruding along the straight edge segment toward the edge direction of the rotor core, and the magnetization direction of the permanent magnet is perpendicular to its length extension direction.

[0010] In one embodiment of the present invention, the plurality of permanent magnets are divided into a plurality of groups according to the number of motor poles.

[0011] In one embodiment of the present invention, the number of permanent magnets in each group is six.

[0012] In one embodiment of the present invention, a pole spacing magnetic groove is further provided, wherein the pole spacing magnetic groove is located between two adjacent groups of the permanent magnets to provide a magnetic isolation function to reduce magnetic leakage at the ends of the permanent magnets and between the poles.

[0013] In one embodiment of the present invention, the permanent magnet is connected to the permanent magnet slot by glue.

[0014] In one embodiment of the present invention, the distance H from the permanent magnet to the outer edge of the rotor is between 4.57 mm and 5.25 mm; the minimum spacing d between adjacent permanent magnets is between 2.5 mm and 3.1 mm; the distance R from the center of the shaft to the bottom of the permanent magnet is between 155.8 mm and 157.2 mm; and the distance L from the center of the shaft to the top of the permanent magnet is between 175.0 mm and 177.5 mm.

[0015] The present invention also provides a method for optimizing the permanent magnet arrangement structure of a rotor permanent magnet synchronous motor. Based on the permanent magnet arrangement structure of the rotor permanent magnet synchronous motor, the optimization method is based on a fruit fly optimization algorithm and includes:

[0016] S1. Taking the parameters of the permanent magnet as the parameters to be optimized, a fitness function with the radial and tangential stresses of the permanent magnet as indicators is constructed, wherein the parameters of the permanent magnet include the distance H from the permanent magnet to the outer edge of the rotor, the minimum spacing d between adjacent permanent magnets, the distance R from the center of the shaft to the bottom of the permanent magnet, and the distance L from the center of the shaft to the top of the permanent magnet;

[0017] S2, randomly initialize the position of each fruit fly individual in the fruit fly population, and set the maximum number of iterations and population size;

[0018] S3, respectively calculating the distance between the fruit fly individual and the origin and the taste concentration judgment value, and obtaining the taste concentration of the fruit fly individual according to the taste concentration judgment value and the fitness function;

[0019] S4, according to the flavor concentration of the fruit fly individual, finding the maximum flavor concentration in the fruit fly population, and obtaining the position of the fruit fly individual at this time;

[0020] S5, retaining the optimal flavor concentration value and the position of the fruit fly individual at this time, and the fruit fly group uses vision to fly to this position;

[0021] S6, iterative optimization, repeat steps S2-S4, and determine whether the current flavor concentration is greater than the optimal flavor concentration of the previous iteration, and the current number of iterations is less than the maximum number of iterations. If so, execute step S5, otherwise, end the iteration.

[0022] In one embodiment of the present invention, a crossover algorithm in a genetic algorithm is introduced on the basis of the fruit fly algorithm, and the crossover rate and mutation rate in the fruit fly algorithm are optimized according to the flavor concentration and the number of iterations, wherein:

[0023]

[0024] Where: q a is the crossover probability; q amax ,q amin is the maximum and minimum crossover probability; q mmax ,q mmin is the maximum and minimum mutation probability; maxgen is the maximum number of iterations of the algorithm; gener is the current number of iterations, s aνg is the average fitness of the fruit fly population, s′ is the two fruit fly individuals to be crossed, and s is the individual concentration value to be mutated.

[0025] In one embodiment of the present invention, in order to reduce the possibility of the fruit fly algorithm entering a local optimal solution, q amax =0.65,q amin =0.35, in order to enhance the optimization ability of the fruit fly iteration process, q mmax =0.84,q mm i n =0.16.

[0026] In one embodiment of the present invention, the fitness function is:

[0027] min(f)=w r |σ r |+w θ |σ θ |

[0028]

[0029] Where: μ θr , μ rθ are the radial and tangential Poisson’s ratios of the permanent magnet, respectively; E r 、E θ is the tangential and radial elastic modulus of the permanent magnet; β θ , β r are the tangential and radial thermal expansion coefficients of the permanent magnet; ΔT is the temperature change at the radius R from the center of the motor; σ r , σ θ are the radial and tangential stresses of the permanent magnet at a radius R from the center of the motor; is the radial strain; w r and w θ is the weight factor.

[0030] The above technical solution of the present invention has the following advantages compared with the prior art:

[0031] The permanent magnet arrangement structure and optimization method of a rotor permanent magnet synchronous motor described in the present invention improves the structure and distribution of permanent magnets, arranges evenly arranged dispersed permanent magnets on rotor punching sheets, and uses glue to tightly fit the permanent magnets with steamed bun-shaped permanent magnet slots. Six magnetic steels are evenly arranged per pole to reduce the stress concentration of the rotor core and improve the strength of the motor rotor. Multiple permanent magnet slots with equal intervals are formed on the rotor punching sheets to simplify the embedding process of the permanent magnets. Polar interval magnetic slots are set to reduce the leakage of permanent magnet ends and poles, and improve the utilization rate of permanent magnets. At the same time, an improved fruit fly genetic algorithm is used to introduce the crossover rate and mutation rate to optimize the distance H from the permanent magnet to the outer edge of the rotor, the minimum distance d between steamed bun-shaped permanent magnets, the distance R from the center of the shaft to the bottom of the steamed bun-shaped permanent magnet, and the distance L from the center of the shaft to the top of the steamed bun-shaped permanent magnet to reduce the stress on the rotor during the high-speed rotation of the motor and improve the strength of the permanent magnet synchronous motor rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0033] Figure 1 It is a schematic diagram of the overall structure of the permanent magnet arrangement structure of the rotor permanent magnet synchronous motor of the present invention.

[0034] Figure 2 It is a schematic diagram of main parameters of the permanent magnet arrangement structure of the rotor permanent magnet synchronous motor of the present invention.

[0035] Description of the Figures in the Specification:

[0036] 1. Rotor core; 2. Pole spacing magnetic slots; 3. Permanent magnets; 4. Permanent magnet slots. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0038] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0039] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0040] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0041] Example 1

[0042] Reference Figure 1 As shown, this embodiment provides a permanent magnet 3 arrangement structure of a rotor permanent magnet synchronous motor, including:

[0043] Rotor core 1;

[0044] A plurality of permanent magnet slots 4 are evenly distributed along the circumferential direction at intervals on the edge of the rotor core 1;

[0045] A plurality of permanent magnets 3 are correspondingly arranged in each of the permanent magnet slots 4;

[0046] The geometrical profile of the permanent magnet 3 includes a straight edge segment and an arched segment protruding along the straight edge segment toward the edge direction of the rotor core 1 , and the magnetization direction of the permanent magnet 3 is perpendicular to its length extension direction.

[0047] By evenly distributing multiple permanent magnet slots 4 on the edge of the rotor core 1 and arranging a distributed permanent magnet 3 in each slot, the stress concentration problem that is easily generated in the traditional monolithic magnetic pole design is avoided. This distributed arrangement effectively reduces the centrifugal stress on the rotor core 1 when rotating at high speed, thereby improving the overall strength and stability of the rotor. Multiple permanent magnet slots 4 are formed at equal intervals on the rotor punching, making the embedding process of the permanent magnet 3 easier and improving production efficiency. At the same time, the permanent magnet 3 is tightly fitted to the slot using glue to ensure the stability and consistency of the structure.

[0048] Specifically, the plurality of permanent magnets 3 are divided into a plurality of groups according to the number of motor poles.

[0049] Specifically, the number of permanent magnets 3 in each group is six.

[0050] Specifically, it also includes setting a pole spacing magnetic slot 2, which is located between two adjacent groups of permanent magnets 3, and is used to provide a magnetic isolation function to reduce magnetic leakage at the ends and between poles of the permanent magnets 3. By setting the pole spacing magnetic slot 2, which is located between two adjacent groups of permanent magnets 3, and providing a magnetic isolation function, the magnetic leakage phenomenon at the ends and between poles of the permanent magnets 3 is reduced. This not only improves the magnetic field utilization efficiency of the permanent magnets 3, but also enhances the overall performance of the motor.

[0051] Specifically, the permanent magnet 3 is connected to the permanent magnet slot 4 by glue.

[0052] Specifically, the distance H from the permanent magnet 3 to the outer edge of the rotor is between 4.57 mm and 5.25 mm; the minimum spacing d between adjacent permanent magnets 3 is between 2.5 mm and 3.1 mm; the distance R from the center of the shaft to the bottom of the permanent magnet 3 is between 155.8 mm and 157.2 mm; and the distance L from the center of the shaft to the top of the permanent magnet 3 is between 175.0 mm and 177.5 mm.

[0053] Example 2

[0054] The present embodiment also provides an optimization method for the arrangement structure of the permanent magnet 3 of the rotor permanent magnet synchronous motor. Based on the arrangement structure of the permanent magnet 3 of the rotor permanent magnet synchronous motor, the optimization method is based on the fruit fly optimization algorithm, adopts the improved fruit fly optimization algorithm, and introduces the crossover rate and mutation rate in the genetic algorithm to optimize the key parameters (H, d, R, L) of the permanent magnet 3. This optimization process effectively reduces the stress generated by the rotor during high-speed rotation, and further improves the strength of the rotor and the reliability of the motor. The optimization method includes:

[0055] S1. The parameters of the permanent magnet 3 are taken as the parameters to be optimized, and a fitness function with the radial and tangential stresses of the permanent magnet 3 as indicators is established. The parameters of the permanent magnet 3 include the distance H from the permanent magnet 3 to the outer edge of the rotor, the minimum spacing d between adjacent permanent magnets 3, the distance R from the center of the shaft to the bottom of the permanent magnet 3, and the distance L from the center of the shaft to the top of the permanent magnet 3. When the fruit fly genetic algorithm is used for optimization, on the one hand, it is necessary to consider minimizing the stress on the rotor, and on the other hand, it is also necessary to consider the processing problem, so the value range of the required optimization amount should be selected:

[0056] The distance H from the permanent magnet 3 to the rotor extension is 4.57 mm to 5.25 mm.

[0057] Minimum distance d between three bun-shaped permanent magnets: 2.5mm~3.1mm

[0058] Distance R from the center of the shaft to the bottom of the bun-shaped permanent magnet 3: 155.8mm~157.2mm

[0059] The distance L from the center of the rotating shaft to the top of the steamed bun-shaped permanent magnet 3 is 175.0 mm to 177.5 mm.

[0060] S2, randomly initialize the position of each fruit fly individual in the fruit fly population, and set the maximum number of iterations and population size;

[0061] Position initialization.

[0062]

[0063] In the formula, x.axis is the initial position of the fruit fly individual in the x-axis direction. y.axis is the initial position of the fruit fly individual in the y-axis direction. random(LR) means generating a random number within the given range LR. The number of iterations maxgen is 100 iterations, and the population size sizepop is set to 60.

[0064] maxgen=100;

[0065] sizepop=60.

[0066] S3, respectively calculating the distance between the fruit fly individual and the origin and the taste concentration judgment value, and obtaining the taste concentration of the fruit fly individual according to the taste concentration judgment value and the fitness function;

[0067] S4, according to the flavor concentration of the fruit fly individual, finding the maximum flavor concentration in the fruit fly population, and obtaining the position of the fruit fly individual at this time;

[0068] S5, retaining the optimal flavor concentration value and the position of the fruit fly individual at this time, and the fruit fly group uses vision to fly to this position;

[0069] S6, iterative optimization, repeat steps S2-S4, and determine whether the current flavor concentration is greater than the optimal flavor concentration of the previous iteration, and the current number of iterations is less than the maximum number of iterations. If so, execute step S5, otherwise, end the iteration.

[0070] Specifically, it also includes introducing the crossover algorithm in the genetic algorithm based on the fruit fly algorithm, and optimizing the crossover rate and mutation rate in the fruit fly algorithm according to the flavor concentration and the number of iterations, wherein:

[0071]

[0072] Where: q a is the crossover probability; q amax ,q amin is the maximum and minimum crossover probability; q mmax ,q mminis the maximum and minimum mutation probability; maxgen is the maximum number of iterations of the algorithm; gener is the current number of iterations, s aνg is the average fitness of the fruit fly population, s′ is the two fruit fly individuals to be crossed, and s is the individual concentration value to be mutated.

[0073] Specifically, in order to reduce the possibility of the fruit fly algorithm entering the local optimal solution, take q amax =0.65,q am i n =0.35, in order to enhance the optimization ability of the fruit fly iteration process, q mmax =0.84,q mmin =0.16.

[0074] Specifically, the fitness function is:

[0075] min(f)=w r |σ r |+w θ |σ θ |

[0076]

[0077] Where: μ θr , μ rθ are the radial and tangential Poisson's ratios of the permanent magnet 3 respectively; E r 、E θ is the tangential and radial elastic modulus of the permanent magnet 3; β θ , β r is the tangential and radial thermal expansion coefficient of the permanent magnet 3; ΔT is the temperature change at the radius R from the center of the motor; σ r , σ θ are the radial and tangential stresses of the permanent magnet 3 at a radius R from the motor center; is the radial strain, u is the displacement, and r is the radius. r and w θ is a weight factor, which can be adjusted according to the design focus.

[0078] By optimizing H, d, R, and L, the stress distribution can be adjusted to minimize σ r and σ θ , thereby improving the mechanical strength of the rotor and the overall performance of the motor.

[0079] By changing the value range of H, d, R, and L and using the fruit fly genetic algorithm to iterate the optimization process, the value of f can be gradually reduced, thereby obtaining a structural parameter configuration with less stress and higher rotor strength.

[0080] The displacement field and strain field are usually obtained through finite element stress-strain analysis (FEA). For the geometric layout of given parameters H, d, R, and L, the stiffness and strength simulation analysis of the motor rotor can be performed and extracted from the stress-strain field calculation results.

[0081] It should be noted that H (the distance from the permanent magnet 3 to the outer edge of the rotor) affects the stress condition and magnetic field distribution of the permanent magnet 3. Too close a distance may lead to stress concentration; d (the minimum spacing between adjacent permanent magnets 3) affects the uniformity and magnetic leakage of the magnetic field. Reasonable spacing can reduce stress concentration and magnetic leakage; R (the distance from the center of the shaft to the bottom of the permanent magnet 3) affects the stress distribution of the permanent magnet 3 in the rotor. A moderate distance helps to disperse the stress; L (the distance from the center of the shaft to the top of the permanent magnet 3) is similar to R, affecting the overall stress of the permanent magnet 3 and the rotor stress distribution.

[0082] Therefore, H, R, and L determine the position of the permanent magnet 3 in the rotor, affecting the centrifugal force and the resulting radial and tangential stresses that the rotor bears during rotation. d affects the magnetic field interference and mechanical stress distribution between the permanent magnets 3. The rationality of the spacing helps to evenly distribute the stress and avoid stress concentration.

[0083] Finally, the optimal solutions for the distance H from the permanent magnet 3 to the outer edge of the rotor, the minimum distance d between the steamed bun-shaped permanent magnets 3, the distance R from the center of the shaft to the bottom of the steamed bun-shaped permanent magnet 3, and the distance L from the center of the shaft to the top of the steamed bun-shaped permanent magnet 3 within the limit range are 5mm, 2.8mm, 156.3mm and 176.5mm respectively.

[0084] The present invention improves the structure and distribution of the permanent magnets 3, arranges evenly distributed dispersed permanent magnets 3 on the rotor punching sheet, and uses glue to tightly fit the permanent magnets 3 with the steamed bun-shaped permanent magnet slots 4. At the same time, an improved fruit fly genetic algorithm is used to introduce the crossover rate and mutation rate to optimize the distance H from the permanent magnet 3 to the outer edge of the rotor, the minimum distance d between the steamed bun-shaped permanent magnets 3, the distance R from the center of the shaft to the bottom of the steamed bun-shaped permanent magnet 3, and the distance L from the center of the shaft to the top of the steamed bun-shaped permanent magnet 3 to reduce the stress on the rotor during the high-speed rotation of the motor and improve the strength of the permanent magnet synchronous motor rotor.

[0085] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0086] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0087] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0089] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A permanent magnet arrangement structure of a rotor permanent magnet synchronous motor, characterized in that: include: Rotor core; A plurality of permanent magnet slots are evenly distributed at intervals along the circumferential direction on the edge of the rotor core; A plurality of permanent magnets are correspondingly arranged in each of the permanent magnet slots; The geometrical profile of the permanent magnet includes a straight edge segment and an arched segment protruding along the straight edge segment toward the edge direction of the rotor core, and the magnetization direction of the permanent magnet is perpendicular to its length extension direction.

2. The permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 1, characterized in that: The plurality of permanent magnets are divided into a plurality of groups according to the number of motor poles.

3. The permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 2, characterized in that: The number of permanent magnets in each group is six.

4. The permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 2, characterized in that: It also includes setting a pole spacing magnetic groove, which is located between two adjacent groups of permanent magnets and is used to provide a magnetic isolation function to reduce magnetic leakage at the ends of the permanent magnets and between poles.

5. The permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 1, characterized in that: The permanent magnet is connected in the permanent magnet slot by glue.

6. The permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 1, characterized in that: The distance H from the permanent magnet to the outer edge of the rotor is 4.57 mm to 5.25 mm; the minimum spacing d between adjacent permanent magnets is 2.5 mm to 3.1 mm; the distance R from the center of the shaft to the bottom of the permanent magnet is 155.8 mm to 157.2 mm; and the distance L from the center of the shaft to the top of the permanent magnet is 175.0 mm to 177.5 mm.

7. A method for optimizing the permanent magnet arrangement structure of a rotor permanent magnet synchronous motor, characterized in that: Based on the permanent magnet arrangement structure of the rotor permanent magnet synchronous motor according to any one of claims 1 to 6, the optimization method is based on a fruit fly optimization algorithm, comprising: S1. Taking the parameters of the permanent magnet as the parameters to be optimized, a fitness function with the radial and tangential stresses of the permanent magnet as indicators is constructed, wherein the parameters of the permanent magnet include the distance H from the permanent magnet to the outer edge of the rotor, the minimum spacing d between adjacent permanent magnets, the distance R from the center of the shaft to the bottom of the permanent magnet, and the distance L from the center of the shaft to the top of the permanent magnet; S2, randomly initialize the position of each fruit fly individual in the fruit fly population, and set the maximum number of iterations and population size; S3, respectively calculating the distance between the fruit fly individual and the origin and the taste concentration judgment value, and obtaining the taste concentration of the fruit fly individual according to the taste concentration judgment value and the fitness function; S4, according to the flavor concentration of the fruit fly individual, finding the maximum flavor concentration in the fruit fly population, and obtaining the position of the fruit fly individual at this time; S5, retaining the optimal flavor concentration value and the position of the fruit fly individual at this time, and the fruit fly group now uses vision to fly to this position; S6, iterative optimization, repeat steps S2-S4, and determine whether the current flavor concentration is greater than the optimal flavor concentration of the previous iteration, and the current number of iterations is less than the maximum number of iterations. If so, execute step S5, otherwise, end the iteration.

8. The method for optimizing the permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 7, characterized in that: It also includes introducing the crossover algorithm in the genetic algorithm based on the fruit fly algorithm, and optimizing the crossover rate and mutation rate in the fruit fly algorithm according to the flavor concentration and the number of iterations, where: Where: q a is the crossover probability; q amax ,q am i n is the maximum and minimum crossover probability; q mmax ,q mm i n is the maximum and minimum mutation probability; maxgen is the maximum number of iterations of the algorithm; gener is the current number of iterations, s aνg is the average fitness of the fruit fly population, s′ is the two fruit fly individuals to be crossed, and s is the individual concentration value to be mutated.

9. The method for optimizing the permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 1, characterized in that: In order to reduce the possibility of the fruit fly algorithm entering the local optimal solution, q amax =0.65,q am i n =0.35, in order to enhance the optimization ability of the fruit fly iteration process, q mmax =0.84,q mm i n =0.

16.

10. The method for optimizing the permanent magnet arrangement structure of a rotor permanent magnet synchronous motor according to claim 1, characterized in that: The fitness function is: min(f)=w r | s r | +w θ | s θ | Where: μ θr , μ rθ are the radial and tangential Poisson’s ratios of the permanent magnet, respectively; E r 、E θ is the tangential and radial elastic modulus of the permanent magnet; β θ , β r are the tangential and radial thermal expansion coefficients of the permanent magnet; ΔT is the temperature change at the radius R from the center of the motor; σ r , σ θ are the radial and tangential stresses of the permanent magnet at a radius R from the center of the motor; is the radial strain; w r and w θ is the weight factor.

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