Magnetic suspension permanent magnet synchronous motor stator structure and design method thereof

Abstract

The invention relates to a stator structure of a magnetic suspension permanent magnet synchronous motor and a design method thereof. The stator comprises a stator core, and the stator core comprises a central hole, an inner side groove and an outer side groove. The multiple inner side grooves extend outwards in the radial direction of the center hole and are distributed at intervals. The plurality of outer side grooves extend inwards in the radial direction along the edge of the stator core and are distributed at intervals; the outer side grooves and the inner side grooves are correspondingly arranged in number and position; one side of each coil in the winding is arranged in the inner side groove, and the other side of each coil in the winding is arranged in the corresponding outer side groove. The invention provides a stator structure of a magnetic suspension permanent magnet synchronous motor and a design method thereof, and aims to shorten the end part of a winding, reduce the axial length of the motor, and determine the optimal distance between inner and outer slots of the stator, the width of the outer slot, the width of the outer slot opening and the depth of the outer slot opening by utilizing a fruit fly optimization algorithm. Therefore, collaborative optimization of the stator flux density, the cogging torque and the average torque is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor design, and in particular to a magnetic suspension permanent magnet synchronous motor stator structure and a design method thereof. Background Art

[0002] With the rapid development of global industrialization, the demand for magnetic levitation permanent magnet motors has become increasingly strong. With the characteristics of small size, high power density, fast dynamic response and low system noise, magnetic levitation permanent magnet motors are widely used in blowers, magnetic levitation centrifugal compressors and other equipment.

[0003] In order to achieve higher speeds, the number of motor poles is usually set to a lower value, such as a 2-pole motor. Although this approach helps to increase the speed, it also brings about the problem of increased pole pitch and increased length of the winding end. The increase in pole pitch means that the distribution of the magnetic field in space becomes more sparse, which may lead to a decrease in the utilization rate of magnetic energy; and the increase in the length of the winding end increases the axial length of the motor, which not only takes up more space, but may also further reduce the efficiency of the motor due to the increase in the resistance and inductance of the winding. In addition, excessive axial length may also have an adverse effect on the strength of the rotor and increase the risk of deformation of the rotor during high-speed rotation. When the stator magnetic density is too large, the iron loss of the motor will increase, resulting in severe heat generation and reduced motor efficiency. The cogging torque will cause the motor to vibrate and make noise, and the speed will fluctuate, affecting the performance of the motor. Summary of the invention

[0004] To this end, the present invention provides a magnetic levitation permanent magnet synchronous motor stator structure and a design method thereof, which shortens the winding ends and reduces the axial length of the motor, and determines the optimal motor parameters by utilizing a fruit fly optimization algorithm, thereby increasing the efficiency and strength of the motor.

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

[0006] A stator core, the stator core comprising a center hole, inner slots and outer slots; wherein a plurality of the inner slots extend radially outwardly along the center hole and are spaced apart; a plurality of the outer slots extend radially inwardly along the edge of the stator core and are spaced apart; the number and positions of the outer slots and the inner slots are correspondingly arranged;

[0007] A winding, wherein one side of each coil in the winding is placed in the inner slot and the other side is placed in the corresponding outer slot.

[0008] In one embodiment of the present invention, the plurality of inner grooves are evenly distributed along the circumferential direction.

[0009] In one embodiment of the present invention, the plurality of outer grooves are evenly distributed along the circumferential direction.

[0010] In one embodiment of the present invention, a symmetrical longitudinal section of the inner groove along its length direction coincides with a symmetrical longitudinal section of the corresponding outer groove.

[0011] The present invention also provides a design method for a magnetic levitation permanent magnet synchronous motor stator structure. Based on the magnetic levitation permanent magnet synchronous motor stator structure, the method is based on a fruit fly optimization algorithm and includes:

[0012] S1. The parameters of the stator structure are taken as parameters to be optimized, and a fitness function with minimum stator flux density, minimum tooth slot torque and maximum average torque as indicators is established. The parameters of the stator structure include the distance d between the inner and outer slots of the stator, the width b of the outer slot, and the width B of the outer slot opening. s0 and the outer groove opening depth H s0 ;

[0013] S2, randomly initialize the position of each fruit fly individual in the fruit fly population;

[0014] S3, randomly assign the direction and distance to find food;

[0015] S4, 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;

[0016] S5. Finding the maximum value of the flavor concentration in the fruit fly population according to the flavor concentration of the fruit fly individual, and obtaining the position of the fruit fly individual at this time;

[0017] S6, 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;

[0018] S7, iterative optimization, repeat steps S2-S5, and judge the current taste and the previous generation taste concentration. If it is greater than the current taste concentration, execute step S6. If it is less than, save the previous generation taste concentration and end.

[0019] In one embodiment of the present invention, in order to simultaneously achieve the minimum stator flux density, the minimum cogging torque and the maximum average torque, a multi-objective optimization function of weight coefficients is adopted, that is, the fitness function is:

[0020]

[0021] Where w1, w2 and w3 are the average torque T avg , cogging torque T cog and the weight coefficient of stator flux density B, the units of w1 and w2 are N·m and N·m respectively -1, the unit of w3 is T, the value range of w1, w2 and w3 is 0~1, the larger the weight coefficient is, the larger the proportion of the target is.

[0022] The above technical solution of the present invention has the following advantages compared with the prior art:

[0023] The stator structure of a magnetic levitation permanent magnet synchronous motor and its design method described in the present invention doubles the number of winding coils and places one side of each coil constituting the winding in a slot on the inner side of the stator and the other side in a corresponding slot on the outer side, so that the distance between the two sides becomes shorter, thereby shortening the winding end and reducing the axial length of the motor, thereby increasing the efficiency and strength of the motor. By using the fruit fly optimization algorithm, the optimal motor parameters (the distance d between the inner and outer slots of the stator, the width b of the outer slot, the width B of the outer slot opening) are determined. s0 and the outer groove opening depth H s0 ) to achieve the optimal coordination of stator flux density, cogging torque and average torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

[0025] Figure 1 It is a schematic diagram of the overall structure of the stator structure of the magnetic levitation permanent magnet synchronous motor of the present invention.

[0026] Description of the Figures in the Specification:

[0027] 100, stator core; 110, center hole; 120, inner slot; 130, outer slot. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Example 1

[0033] Reference Figure 1 As shown, this embodiment provides a stator structure of a magnetic levitation permanent magnet synchronous motor, including:

[0034] A stator core 100, the stator core 100 comprising a central hole 110, inner slots 120 and outer slots 130; wherein a plurality of the inner slots 120 extend radially outwardly along the central hole 110 and are distributed at intervals; a plurality of the outer slots 130 extend radially inwardly along the edge of the stator core 100 and are distributed at intervals; the number and position of the outer slots 130 and the inner slots 120 are arranged correspondingly;

[0035] The winding has one side of each coil placed in the inner slot 120 and the other side placed in the corresponding outer slot 130. The current magnitude and direction of the coil in the inner slot 120 are consistent with the current magnitude and direction at the corresponding position in the original winding method.

[0036] By placing one side of the winding coil in the inner slot 120 of the stator and the other side in the corresponding outer slot 130, the distance between the two ends of the winding is greatly reduced. This design effectively shortens the length of the winding end, thereby reducing the axial length of the motor. The shortening of the length of the winding end directly leads to a reduction in the overall axial length of the motor. This not only saves space and is suitable for space-constrained application scenarios, but also improves the mechanical compactness and overall integration of the motor.

[0037] It should be noted that in traditional motors, winding coils are usually all embedded in slots located on the inner side of the stator, while the present invention places one side of each winding coil in the inner slot 120 and the other side in the outer slot 130 directly opposite thereto. In this way, the two sides of the coil (two straight segments) are radially distributed on the inner and outer sides of the stator core 100. This layout does not change the magnitude and direction of the current flowing through the winding, and only redistributes the spatial position compared to the originally designed winding arrangement. This means that the motor still maintains the original winding phase sequence and magnetic field generation characteristics, but achieves structural and performance optimization by changing the spatial placement of the coil.

[0038] Specifically, the plurality of inner grooves 120 are evenly distributed along the circumference, and the plurality of outer grooves 130 are evenly distributed along the circumference, which helps to ensure that the magnetic field distribution inside the motor is more symmetrical, reduce unbalance factors, and improve the stability of the motor operation.

[0039] Specifically, the symmetrical longitudinal section of the inner slot 120 along its length direction coincides with the symmetrical longitudinal section of the corresponding outer slot 130. The corresponding arrangement of the number and position of the inner and outer slots 130 realizes the uniform distribution of the winding coils in the stator slots. This design helps to balance the distribution of electromagnetic force, reduce the negative impact of unbalanced magnetic field, and improve the overall performance and life of the motor.

[0040] Example 2

[0041] This embodiment provides a design method for a stator structure of a magnetic levitation permanent magnet synchronous motor. Based on the stator structure of the magnetic levitation permanent magnet synchronous motor, the method is based on a fruit fly optimization algorithm (FOA) and includes:

[0042] S1. The parameters of the stator structure are taken as parameters to be optimized, and a fitness function with minimum stator flux density, minimum tooth slot torque and maximum average torque as indicators is established. The parameters of the stator structure include the distance d between the inner and outer slots of the stator, the width b of the outer slot (affecting the path and uniformity of the magnetic flux passing through the outer slot), and the width B of the outer slot opening. s0 and the outer groove opening depth H s0 (These two parameters determine the shape and depth of the outer slot entrance, thereby affecting the degree of magnetic flux concentration and the electromagnetic conditions inside the slot).

[0043] Specifically, in order to simultaneously achieve the minimum stator flux density, the minimum cogging torque and the maximum average torque, a multi-objective optimization function with weight coefficients is adopted, that is, the fitness function is:

[0044]

[0045] Where w1, w2 and w3 are the average torque T avg , cogging torque T cogand the weight coefficient of stator flux density B, the units of w1 and w2 are N·m and N·m respectively -1 , the unit of w3 is T, the value range of w1, w2 and w3 is 0~1, the larger the weight coefficient is, the larger the proportion of the target is.

[0046] Average torque T avg As large as possible to increase the effective power output of the motor. cog As small as possible to reduce the vibration and noise of the motor. The stator flux density B is as small as possible to reduce iron loss and overheating problems. By combining the three objectives into a comprehensive objective function and setting weight coefficients w1, w2 and w3, the importance of different objectives is adjusted to find the best compromise between multiple objectives. This multi-objective optimization method ensures that the motor reaches a better level in multiple key performance indicators at the same time.

[0047] It should be noted that the stator flux density is affected by the geometric shape and size of the stator slots. The distance d between the inner and outer slots of the stator and the width b of the outer slots will affect the distribution of the magnetic flux, thereby affecting the stator flux density B. The outer slot opening width b and the outer slot opening depth H s0 It will also affect the concentration of magnetic flux, and thus affect the stator magnetic flux density B. The distance d between the inner and outer slots of the stator and the width b of the outer slot will affect the distribution of magnetic flux, thereby affecting the cogging torque T cog The width b of the outer slot and the width b of the outer slot will affect the path and distribution of the magnetic flux, and thus affect the cogging torque T cog The size and distribution of the stator inner and outer slots distance d and the width b of the outer slots will affect the number of turns of the winding, thus affecting the average torque T avg . Outer groove opening width B s0 and the outer groove opening depth H s0 It will affect the distribution of magnetic flux and thus the average torque T avg .

[0048] By establishing a multi-objective optimization function including average torque, cogging torque and stator flux density, and comprehensively considering multiple performance indicators, the coordinated optimization of various motor performances is achieved. This comprehensive optimization method ensures that the motor can achieve optimal performance in multiple aspects and avoids the limitations of single optimization.

[0049] S2, randomly initialize the position of each fruit fly individual in the fruit fly population; this is equivalent to randomly generating a set of initial solutions in the parameter space;

[0050] InitX_axis

[0051] InitY_axis

[0052] S3, randomly assign the direction and distance to find food;

[0053] X i =X_axis+RandomValue

[0054] Y i =Y_axis+RandomValue

[0055] S4, calculate the distance between the fruit fly individual and the origin (Dist i ) and taste concentration judgment value (S i ), according to the smell concentration judgment value and the fitness function (Fitness), the smell concentration (Smell i );in,

[0056]

[0057] S i =1 / Dist i

[0058] Smell i =Fitness(S i )

[0059] S5. Finding the maximum value of the flavor concentration in the fruit fly population according to the flavor concentration of the fruit fly individual, and obtaining the position of the fruit fly individual at this time;

[0060] [bestSmellbestIndex]=max(smell)

[0061] S6, 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;

[0062] X axis =X(bestIndex)

[0063] Y axis =Y(bestIndex)

[0064] S7, iterative optimization, repeat steps S2-S5, and judge the current taste and the previous generation taste concentration. If it is greater than the current taste concentration, execute step S6. If it is less than, save the previous generation taste concentration and end.

[0065] It should be noted that the average torque is obtained through loaded electromagnetic transient simulation, the cogging torque is obtained through transient magnetic field analysis under no-load idling, and the stator magnetic flux is obtained through static or transient electromagnetic field finite element analysis to extract the magnetic flux values ​​at key positions from the magnetic field distribution.

[0066] By optimizing the distance d between the inner and outer slots of the stator, the width b of the outer slot, and the width B of the outer slot opening s0and the outer groove opening depth H s0 The fruit fly optimization algorithm is used to achieve the coordinated optimization of stator magnetic flux density, tooth slot torque and average torque, which significantly improves the magnetic energy utilization efficiency of the motor, reduces iron loss and copper loss, and thus improves the overall working efficiency of the motor.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0071] 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 magnetic levitation permanent magnet synchronous motor stator structure, characterized in that: include: A stator core (100), the stator core (100) comprising a central hole (110), inner slots (120) and outer slots (130); wherein a plurality of the inner slots (120) extend radially outward along the central hole (110) and are spaced apart; wherein a plurality of the outer slots (130) extend radially inward along an edge of the stator core (100) and are spaced apart; and wherein the number and positions of the outer slots (130) and the inner slots (120) are arranged correspondingly; A winding, wherein one side of each coil in the winding is placed in the inner slot (120) and the other side is placed in the corresponding outer slot (130).

2. The stator structure of a magnetic levitation permanent magnet synchronous motor according to claim 1, characterized in that: The plurality of inner grooves (120) are evenly distributed along the circumferential direction.

3. The stator structure of a magnetic levitation permanent magnet synchronous motor according to claim 1, characterized in that: The plurality of outer grooves (130) are evenly distributed along the circumferential direction.

4. The stator structure of a magnetic levitation permanent magnet synchronous motor according to claim 1, characterized in that: The symmetrical longitudinal section of the inner groove (120) along its length direction coincides with the symmetrical longitudinal section of the corresponding outer groove (130).

5. A method for designing a stator structure of a magnetic levitation permanent magnet synchronous motor, characterized in that: Based on the stator structure of the magnetic levitation permanent magnet synchronous motor according to any one of claims 1 to 4, the method is based on a fruit fly optimization algorithm, comprising: S1. The parameters of the stator structure are taken as parameters to be optimized, and a fitness function with minimum stator flux density, minimum tooth slot torque and maximum average torque as indicators is established. The parameters of the stator structure include the distance d between the inner and outer slots of the stator, the width b of the outer slot, and the width B of the outer slot opening. s0 and the outer groove opening depth H s0 ; S2, randomly initialize the position of each fruit fly individual in the fruit fly population; S3, randomly assign the direction and distance to find food; S4, 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; S5. Finding the maximum value of the flavor concentration in the fruit fly population according to the flavor concentration of the fruit fly individual, and obtaining the position of the fruit fly individual at this time; S6, 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; S7, iterative optimization, repeat steps S2-S5, and judge the current taste and the previous generation taste concentration. If it is greater than the current taste concentration, execute step S6. If it is less than, save the previous generation taste concentration and end.

6. The method for designing a stator structure of a magnetic levitation permanent magnet synchronous motor according to claim 1, characterized in that: In order to achieve the minimum stator flux density, minimum cogging torque and maximum average torque at the same time, a multi-objective optimization function with weight coefficients is adopted, that is, the fitness function is: ， In the formula , and The average torque , cogging torque and stator flux density The weight coefficient of and The units are N·m and N·m respectively. -1 , The unit is T, , and The value range is 0~1. The larger the weight coefficient is, the greater the proportion of the target is.

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