A design method for magnetic pole array of a magnetic circuit reconfigurable motor

Abstract

This invention relates to the field of motor technology, and more particularly to a design method for a magnetic pole array of a magnetic circuit reconfigurable motor. The method includes: a plurality of permanent magnets and a soft magnetic back iron, wherein the radial contact boundary between the permanent magnets and the soft magnetic back iron is an irregularly shaped boundary. This irregularly shaped boundary is formed by a continuously varying curved profile created by the contact surfaces of the permanent magnets and the soft magnetic back iron, and the curved profile has different radial inner diameters at different circumferential angles. The design method includes: obtaining the basic parameters of the target motor; obtaining several sets of candidate solutions based on the basic parameters and an optimization model of the magnetic pole array of the magnetic circuit reconfigurable motor; optimizing the several sets of candidate solutions according to the optimization objective and desired operating conditions to obtain an optimized solution; and determining the irregularly shaped boundary of the target motor based on the optimized solution. This invention achieves multi-objective collaborative optimization of torque output capability, dynamic response speed, permanent magnet utilization rate, and copper loss in permanent magnet motors.

Description

Technical Field

[0001] This invention relates to the field of motor equipment technology, and in particular to a design method for a magnetic pole array of a magnetic circuit reconfigurable motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in new energy vehicles, industrial servo systems, and aerospace due to their high power density and efficiency. As a core component of the motor, the rotor magnetic pole structure design directly affects the motor's torque characteristics and dynamic response. Traditional PMSM rotors mainly adopt radial or parallel magnetic circuit structures, forming magnetic poles through uniformly distributed permanent magnets and silicon steel back iron sheets. While this design is simple in structure and mature in technology, it has gradually revealed the following technical bottlenecks in high-performance applications:

[0003] First, traditional rotor back irons typically employ an integral silicon steel laminate structure, resulting in high material consumption and structural redundancy, significantly increasing rotor mass. Excessive rotational inertia not only limits the motor's acceleration capability but also reduces system response speed, making it difficult to meet the demanding dynamic performance requirements of applications such as drones and robot joints. Second, the simple planar or stepped boundary connection between the permanent magnet and the back iron leads to a high harmonic content in the air gap magnetic field due to this linear contact method. These spatial harmonics not only cause torque pulsation, affecting operational stability, but also generate additional eddy current losses in the stator core, reducing motor efficiency. More importantly, the harmonic magnetic field crowds out the energy share of the fundamental magnetic field, resulting in generally low fundamental flux utilization in traditional designs, severely restricting torque density improvement.

[0004] To address the aforementioned issues, existing technologies have proposed several improvement schemes, but all have limitations. For example, using a Halbach array to improve the sinusoidal nature of the magnetic field through spatial modulation of the permanent magnet magnetization direction results in a significant increase in manufacturing costs due to the complex assembly process of multiple permanent magnets, and the utilization rate of the permanent magnets is low. While a non-uniform air gap design can reduce cogging torque, the change in air gap permeability increases the magnetic reluctance of the main magnetic flux path, leading to a decrease in output torque under the same current. Other research has attempted to achieve weight reduction through back iron hollowing, but this method offers very limited improvement in performance.

[0005] In summary, simultaneously improving the torque output capability, dynamic response speed, and permanent magnet utilization rate of a motor is extremely challenging. This multi-objective coupling problem urgently needs to be systematically solved through innovative magnetic pole structure reconstruction methods.

[0006] Chinese Patent Publication No. CN107425629A discloses a permanent magnet motor rotor, comprising an alternating pole permanent magnet motor rotor core, two conventional permanent magnet motor rotor cores, and tile-type permanent magnets. One of the conventional permanent magnet motor rotor cores has an axial length 0.1 to 0.3 times the axial length of the entire rotor core and is coaxially arranged on both sides of the alternating pole permanent magnet motor rotor core. The outer or inner circumferential surface of the alternating pole permanent magnet motor rotor core is uniformly provided with p salient poles along the circumferential direction, forming a permanent magnet slot 2 between adjacent salient poles; where p is the number of motor pole pairs. The outer or inner circumferential surface of the conventional permanent magnet motor rotor core is uniformly provided with 2p permanent magnet slots 1 along the circumferential direction; each permanent magnet slot 1 and each permanent magnet slot 2 contains a nested tile-type permanent magnet. This invention combines a traditional surface-type permanent magnet motor rotor with an alternating pole surface-type permanent magnet motor rotor, reducing motor cost and ensuring torque output capability while weakening leakage flux and magnetization at the shaft end. Therefore, the permanent magnet motor rotor has the following problems: the straight / stepped boundary of the permanent magnet causes abrupt changes in the magnetic field, the air gap harmonics increase, the torque pulsation increases, and the iron loss of the rotor increases. Summary of the Invention

[0007] Therefore, this invention provides a design method for a magnetic pole array of a magnetic circuit reconfigurable motor, which overcomes the problem in the prior art that it is difficult to simultaneously improve the torque output capability, dynamic response speed and permanent magnet utilization of the motor.

[0008] To achieve the above objectives, the present invention provides a design method for a magnetic pole array of a magnetic circuit reconfigurable motor, comprising:

[0009] Step S1: Obtain the basic model parameters and optimized basic parameters of the target motor. The basic model parameters include the outer radius of the permanent magnet, the inner radius of the stator, the outer radius of the stator, the bottom radius of the stator slot, the axial length of the stator, the full coverage of the stator slot, the number of winding turns, the stator tooth pitch angle, the number of motor phases, the number of motor pole pairs, the pole arc coefficient, and the input current. The optimized basic parameters include the inner radius of the soft magnetic back iron, the copper material density, the permanent magnet material density, and the soft magnetic back iron material density.

[0010] Step S2: Construct an optimized model of the magnetic pole array of the magnetic circuit reconfigurable motor based on the model basic parameters and magnetic permeability basic parameters of the target motor. The magnetic permeability basic parameters include the vacuum magnetic permeability of the permanent magnet, the relative magnetic permeability of the stator and rotor, and the relative magnetic permeability of the permanent magnet.

[0011] Step S3: Determine the solution sampling range of the optimization model. The solution sampling range includes the radial inner radius sampling range, the stator slot depth sampling range, the stator slot opening width sampling range, and the stator slot bottom width sampling range.

[0012] Step S4: Solve the optimization model within the solution sampling range to obtain several sets of candidate solutions, wherein each set of candidate solutions includes several mutually matching radial inner radius and circumferential angle, electromagnetic torque and copper loss;

[0013] Step S5: Optimize several sets of candidate solutions according to the optimization objectives and desired operating conditions to obtain optimized solutions. The optimization objectives include maximizing the torque density, maximizing the torque-to-inertia ratio, maximizing the permanent magnet utilization efficiency, and minimizing the copper loss of the target motor.

[0014] Step S6: Based on the optimized solution, determine the irregular boundary and stator slot size data of the target motor;

[0015] The irregular boundary is a continuously changing curved profile formed by the contact surface between the permanent magnet and the soft magnetic back iron in the motor magnetic pole array. The curved profile has a corresponding radial inner radius at different circumferential angles. The stator slot size data includes the stator slot depth, stator slot opening width, and stator slot bottom width.

[0016] Further, step S2 includes:

[0017] Step S21: Based on the basic parameters of the target motor model, obtain the solution domain structure model of a single pair of adjacent permanent magnets of the target motor.

[0018] Step S22: Based on the main magnetic flux path of a single pair of magnetic poles, the solution domain structure model is layered a finite number of times to obtain a layered solution domain model;

[0019] Step S23: Based on the solution domain hierarchical model and the fundamental permeability parameters, obtain the optimized model, wherein the optimized model is the solution domain equivalent magnetoresistive network of the solution domain hierarchical model.

[0020] Furthermore, the optimization model includes:

[0021] The stator tangential magnetic permeability distributed along the stator tangential direction;

[0022] The radial magnetic permeability of each stator distributed along the radial direction of the stator;

[0023] Each air gap tangential magnetic permeability is distributed along the tangential direction of the air gap and connected in series with the corresponding stator tangential magnetic permeability.

[0024] Radial magnetic permeability of each air gap distributed along the radial direction of the air gap;

[0025] The radial magnetic permeability of each permanent magnet is distributed along the radial direction of the permanent magnet in two adjacent permanent magnets and is connected in series with the tangential magnetic permeability of each air gap;

[0026] The magnetomotive force of each permanent magnet distributed along the radial direction of the permanent magnet in two adjacent permanent magnets and located between the radial magnetic permeability of the permanent magnet and the radial magnetic permeability of the air gap;

[0027] The tangential magnetic permeability of each soft magnetic back iron is distributed along the tangential direction of the soft magnetic back iron and is connected in series with the radial magnetic permeability of each of the two adjacent permanent magnets respectively.

[0028] Radial magnetic permeability of each soft magnetic back iron distributed along the radial direction of the soft magnetic back iron;

[0029] Tangential leakage magnetic permeability of each permanent magnet distributed along the tangential direction of the permanent magnet in the gap between two adjacent permanent magnets;

[0030] Radial leakage magnetic permeability of each permanent magnet is distributed along the radial direction of the permanent magnet in the gap between two adjacent permanent magnets and connected in series with the radial magnetic permeability of the air gap and the radial magnetic permeability of the soft magnetic back iron on both sides respectively.

[0031] The copper loss is determined by the total copper loss of each phase of the target motor.

[0032] Furthermore, in step S22, the method of performing finite-fold layering is based on the main magnetic flux path, dividing the cross-sections of the permanent magnet, soft magnetic back iron, stator, and air gap into n layers of rectangular frames.

[0033] Where n is a positive integer, the first layer of the rectangular frame is located at the center of the radial section of the permanent magnet's main magnetic flux path, and the nth layer of the rectangular frame is located at the edge of the radial section of the permanent magnet near the adjacent permanent magnet's main magnetic flux path.

[0034] The rectangular frames of each permanent magnet layer model have equal widths along the circumferential direction of the permanent magnet, and each layer of the permanent magnet layer model has a corresponding circumferential angle, with n ranging from [10, 100].

[0035] Furthermore, the main magnetic flux path starts from the N pole of the permanent magnet in a clockwise direction, passes through the irregular boundary to enter the soft magnetic back iron, the N pole of the adjacent permanent magnet and the air gap, the stator, and finally passes through the air gap again to enter the S pole of the permanent magnet.

[0036] Further, in step S23, the optimization model is constructed along each of the rectangular frames in the solution domain hierarchical model. For the optimization model on a single rectangular frame, the components in clockwise order are: the radial magnetic permeability of the permanent magnet, the tangential magnetic permeability of the soft magnetic back iron, the radial magnetic permeability of the permanent magnet of the adjacent permanent magnet, the magnetomotive force of the permanent magnet of the adjacent permanent magnet, the radial magnetic permeability of the air gap, the radial magnetic permeability of the stator, the tangential magnetic permeability of the stator, the radial magnetic permeability of the stator, the radial magnetic permeability of the stator, the radial magnetic permeability of the air gap, and the magnetomotive force of the permanent magnet.

[0037] Furthermore, the portion of the rectangular frame of the individual permanent magnet layered model located within the permanent magnet is trapezoidal.

[0038] Further, step S5 includes:

[0039] Step S51: Determine the torque output characteristics of each candidate solution based on the model basic parameters and optimization basic parameters of the target motor and the electromagnetic torque of each candidate solution.

[0040] Step S52: Select the torque output characteristics and the corresponding copper loss according to the optimization objective and the desired operating condition to obtain the optimized solution.

[0041] Furthermore, the torque output characteristics include: torque density, torque-to-inertia ratio, and permanent magnet utilization rate.

[0042] Furthermore, the torque density is the ratio of electromagnetic torque to the effective mass of the motor, the torque-inertia ratio is the ratio of electromagnetic torque to rotor inertia, and the permanent magnet utilization rate is the ratio of electromagnetic torque to permanent magnet mass.

[0043] Compared with existing technologies, the advantages of this invention lie in its design of an irregularly shaped boundary between the permanent magnet and the soft magnetic back iron, forming a continuously changing curved profile. This allows the radial inner diameter to dynamically adjust with the circumferential angle, reconstructing the magnetic circuit distribution of the magnetic pole array. This design significantly optimizes the proportion of the fundamental component of the air gap magnetic field and reduces harmonic content, thereby synergistically improving torque output capability, dynamic response speed, and permanent magnet utilization. Simultaneously, by balancing torque density, copper loss, and inertia ratio through a multi-objective optimization model, efficient electromechanical energy conversion is achieved on the basis of a lightweight rotor structure, resolving the technical contradiction in traditional permanent magnet motors where torque performance, response speed, and material utilization are difficult to balance.

[0044] Furthermore, this invention optimizes the air gap magnetic flux distribution through irregularly shaped boundaries, enhancing the fundamental magnetic field strength and generating higher electromagnetic torque under the same current excitation. Combined with the lightweight design of the soft magnetic back iron, it significantly improves the torque-to-motor effective mass ratio, ensuring high power density output and meeting the load requirements of high-performance drive scenarios.

[0045] Furthermore, this invention reduces rotor inertia by reconstructing the magnetic pole array and optimizes the magnetic circuit to reduce reluctance torque ripple. The increased electromagnetic torque to rotor inertia ratio significantly shortens acceleration response time and enhances system control accuracy, making it suitable for precision servo applications requiring frequent starts and stops and high-speed modulation.

[0046] Furthermore, this invention guides magnetic flux to efficiently converge in the main magnetic circuit of the air gap through irregularly shaped boundaries, reducing magnetic energy loss caused by leakage flux and harmonics inside the permanent magnet. The effective electromagnetic torque generated per unit mass of permanent magnet is significantly increased, reducing the cost of rare earth materials and achieving efficient resource utilization.

[0047] Furthermore, this invention smooths the magnetic field transition with a continuous curved profile, suppressing stator core eddy currents and additional losses caused by air gap harmonics. Simultaneously, the optimized magnetic circuit shortens the main magnetic flux path, reducing iron and copper losses, improving motor efficiency and thermal management performance, and extending service life.

[0048] Furthermore, this invention quantifies the coupling relationship between electromagnetic torque, copper loss, and inertia through a hierarchical magnetoresistive network model, and achieves a multi-objective balance of torque density, permanent magnet utilization, and dynamic response by combining the Pareto front solution set, providing a universal optimization framework for complex magnetic circuit design and enhancing engineering applicability. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the rotor structure dimensions of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0050] Figure 2 This is a schematic diagram of the stator structure dimensions of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0051] Figure 3 This is a schematic diagram of the solution domain structure model of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0052] Figure 4 This is a schematic diagram of the solution domain layered model of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0053] Figure 5 This is an enlarged view of point A in the schematic diagram of the solution domain layered model of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0054] Figure 6 This is a schematic diagram of the optimized model of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0055] Figure 7 This is a Pareto front diagram of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0056] Figure 8 This is a left view of the Pareto front diagram of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0057] Figure 9 This is a right view of the Pareto front diagram of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0058] Figure 10 This is a top view of the Pareto front of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0059] Figure 11 This is a comparison diagram of the magnetic flux distribution of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0060] Figure 12This is a comparison diagram of the magnetic flux distribution and harmonic content of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0061] Figure 13 This is a comparison diagram of the back electromotive force distribution of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0062] Figure 14 This is a comparison diagram of the back electromotive force distribution and harmonic content of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0063] Figure 15 This is a comparison diagram of the output torque of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention;

[0064] In the diagram, 1-rotor; 11-permanent magnet; 12-soft magnetic back iron; 2-stator; 3-air gap. Detailed Implementation

[0065] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0066] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0067] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0068] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0069] Please see Figure 1 and Figure 2As shown, it is a schematic diagram of the rotor structure dimensions of a magnetic circuit reconfigurable motor pole array according to an embodiment of the present invention, and a schematic diagram of the stator structure dimensions of a magnetic circuit reconfigurable motor pole array according to an embodiment of the present invention; the design method of a magnetic circuit reconfigurable motor pole array according to an embodiment of the present invention includes:

[0070] Step S1: Obtain the basic model parameters and optimized basic parameters of the target motor. The basic model parameters include the outer radius of the permanent magnet, the inner radius of the stator, the outer radius of the stator, the bottom radius of the stator slot, the axial length of the stator, the full coverage of the stator slot, the number of winding turns, the stator tooth pitch angle, the number of motor phases, the number of motor pole pairs, the pole arc coefficient, and the input current. The optimized basic parameters include the inner radius of the soft magnetic back iron, the copper material density, the permanent magnet material density, and the soft magnetic back iron material density.

[0071] In this embodiment of the invention, the basic parameters of the target motor model are denoted as: the outer radius R of the permanent magnet. m Stator inner radius R s Stator outer radius R sto Stator slot bottom radius R slot Stator axial length L, stator slot full coverage β, number of winding turns N, stator tooth pitch angle α y Number of motor phases m, number of motor pole pairs p, pole arc coefficient α p And the input current I.

[0072] Among them, the outer diameter R of the permanent magnet m Inner radius R of the soft magnetic back iron r Stator inner radius R s Stator outer radius R sto Stator slot bottom radius R slot And the stator axial length L, in millimeters (mm); stator tooth pitch angle αy, in degrees (°); polar arc coefficient α p , dimensionless; number of turns N in winding, in turns; input current I, in amperes (A).

[0073] Among them, the stator slot fill factor β is dimensionless, and for cylindrical enameled wire, the typical value range of β is 0.4 to 0.5.

[0074] The optimized basic parameter of the target motor is denoted as the inner radius R of the soft magnetic back iron. r Copper material density ρ Cu Density ρ of permanent magnet material pm , density ρ of soft magnetic back iron material Fe Copper material density ρ Cu Density ρ of permanent magnet material pm , density ρ of soft magnetic back iron material Fe The unit is kilograms per cubic millimeter (kg / mm²) 3 ); Inner radius R of the soft magnetic back ironr The unit is millimeters (mm).

[0075] Those skilled in the art will understand that the basic parameters of the target motor model, the basic parameters for optimization, and the stator slot size data are all parameters with standard definitions in this field. For specific definitions, please refer to [link to relevant documentation]. Figure 1 and Figure 2 As shown, the method for obtaining it will not be repeated here.

[0076] Understandably, for permanent magnet motors, performance indicators such as output torque and permanent magnet utilization are expected to be maximized. However, in practical engineering applications, motor design is limited by factors such as material cost, installation space, and manufacturing process, making it impossible to simultaneously and unlimitedly improve the above performance indicators. Therefore, the basic parameters of the target motor are first obtained. By fixing the structural boundary conditions and electromagnetic constraint framework of the motor, a clear optimization domain is established for subsequent magnetic circuit reconstruction. These basic parameters jointly define the physical boundaries of the motor (such as radial dimension constraints), material usage (such as permanent magnet volume constraints), and electromagnetic characteristics (such as the number of winding turns). This allows the design variables to be focused on the irregular boundary curve between the permanent magnet and the soft magnetic back iron and the stator slot dimensions. This parameter constraint strategy ensures that the basic functions of the motor are realized, and enables the optimization process to optimize the core variables of magnetic circuit reconstruction, avoiding design redundancy and engineering infeasibility caused by the liberalization of global parameters.

[0077] Step S2: Construct an optimized model of the magnetic pole array of the magnetic circuit reconfigurable motor based on the model basic parameters and magnetic permeability basic parameters of the target motor. The magnetic permeability basic parameters include the vacuum magnetic permeability of the permanent magnet, the relative magnetic permeability of the stator and rotor, and the relative magnetic permeability of the permanent magnet.

[0078] Specifically, step S2 includes:

[0079] Step S21: Based on the basic parameters of the target motor model, obtain the solution domain structure model of a single pair of adjacent permanent magnets of the target motor.

[0080] In the embodiments of the present invention, please continue to refer to Figure 3 As shown, it is a schematic diagram of the solution domain structure model of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention. The solution domain structure model is obtained by equivalently mapping the rotor structure and stator structure from a circular ring to a rectangle, which is used to facilitate the construction of the subsequent optimization model.

[0081] Step S22: Based on the main magnetic flux path of a single pair of magnetic poles, the solution domain structure model is layered a finite number of times to obtain a layered solution domain model;

[0082] Specifically, in step S22, the finite-fold layering method involves dividing the cross-sections of the permanent magnet, soft magnetic back iron, stator, and air gap into n rectangular frames based on the main magnetic flux path.

[0083] Where n is a positive integer, the first layer of the rectangular frame is located at the center of the radial section of the permanent magnet's main magnetic flux path, and the nth layer of the rectangular frame is located at the edge of the radial section of the permanent magnet near the adjacent permanent magnet's main magnetic flux path.

[0084] The rectangular frames of each permanent magnet layer model have equal widths along the circumferential direction of the permanent magnet, and each layer of the permanent magnet layer model has a corresponding circumferential angle, with n ranging from [10, 100].

[0085] Specifically, the main magnetic flux path starts clockwise from the N pole of the permanent magnet, passes through the irregular boundary to the soft magnetic back iron, the N pole of the adjacent permanent magnet and the air gap, the stator, and finally passes through the air gap again to the S pole of the permanent magnet.

[0086] Specifically, the portion of the rectangular frame of a single permanent magnet layered model located within the permanent magnet is trapezoidal.

[0087] Please continue reading. Figure 4 and Figure 5 As shown, these are respectively a schematic diagram of the solution domain layering method of a magnetic circuit reconfigurable motor pole array according to an embodiment of the present invention and an enlarged view of point A of the schematic diagram of the solution domain layering model of the magnetic circuit reconfigurable motor pole array according to the present invention.

[0088] In an embodiment of the present invention, according to Figure 4 and Figure 5 The layering method shown describes a finite number of layerings of the solution domain structure model based on the main magnetic flux path of a single pair of magnetic poles. The main magnetic flux path starts clockwise from the N pole of the permanent magnet, passes through the irregular boundary to the soft magnetic back iron, the N pole and air gap of the adjacent permanent magnet, the stator, and finally passes through the air gap again to the S pole of the permanent magnet. There are also leakage magnetic flux paths inside the permanent magnet and between adjacent permanent magnets. The layering method is based on the main magnetic flux path, dividing the cross-sections of the permanent magnet 11, the soft magnetic back iron 12, the stator 2, and the air gap 3 into n rectangular frames, where i is the current layer number. In this embodiment, the first layer is the main magnetic flux path located at the center of the radial section of the permanent magnet, and the nth layer is the main magnetic flux path located near the edge of the radial section of the permanent magnet close to the adjacent permanent magnet. The width of the rectangular frame of each permanent magnet layering model is equal along the circumferential direction of the permanent magnet. For the permanent magnet 11 part of the rectangular frame of the layered model of a single permanent magnet, it is approximately trapezoidal, and the two bases of the trapezoid are R(θ). i And R(θ) i+1The radial inner radius (R(θ)) of the adjacent bottom edge of the permanent magnet 11 parts of the rectangular frame of the adjacent permanent magnet layer model. i The circumferential angles are equal; each layer of permanent magnet has a one-to-one corresponding circumferential angle.

[0089] It is understandable that for an n-layer rectangular frame, there are (n+1) R(θ) elements. i For R(θ) n There exists R(θ). n and R(θ) n ', which correspond to the two bottom sides of the trapezoidal rectangle.

[0090] Step S23: Based on the solution domain hierarchical model and the fundamental permeability parameters, obtain the optimized model, wherein the optimized model is the solution domain equivalent magnetoresistive network of the solution domain hierarchical model.

[0091] Specifically, in step S23, the optimization model is constructed along each of the rectangular frames in the solution domain hierarchical model. For the optimization model on a single rectangular frame, the following components are arranged clockwise: the radial magnetic permeability of the permanent magnet, the tangential magnetic permeability of the soft magnetic back iron, the radial magnetic permeability of the permanent magnet of the adjacent permanent magnet, the magnetomotive force of the permanent magnet of the adjacent permanent magnet, the radial magnetic permeability of the air gap, the radial magnetic permeability of the stator, the tangential magnetic permeability of the stator, the radial magnetic permeability of the stator, the radial magnetic permeability of the stator, the radial magnetic permeability of the air gap, and the magnetomotive force of the permanent magnet.

[0092] Specifically, the optimization model includes:

[0093] The stator tangential magnetic permeability distributed along the stator tangential direction;

[0094] The radial magnetic permeability of each stator distributed along the radial direction of the stator;

[0095] Each air gap tangential magnetic permeable is distributed along the tangential direction of the air gap and connected in series with each stator tangential magnetic permeable;

[0096] Radial magnetic permeability of each air gap distributed along the radial direction of the air gap;

[0097] The radial magnetic permeability of each permanent magnet is distributed along the radial direction of the permanent magnet in two adjacent permanent magnets and is connected in series with the tangential magnetic permeability of each air gap;

[0098] The magnetomotive force of each permanent magnet distributed along the radial direction of the permanent magnet in two adjacent permanent magnets and located between the radial magnetic permeability of the permanent magnet and the radial magnetic permeability of the air gap;

[0099] The tangential magnetic permeability of each soft magnetic back iron is distributed along the tangential direction of the soft magnetic back iron and is connected in series with the radial magnetic permeability of each of the two adjacent permanent magnets respectively.

[0100] Radial magnetic permeability of each soft magnetic back iron distributed along the radial direction of the soft magnetic back iron;

[0101] Tangential leakage magnetic permeability of each permanent magnet distributed along the tangential direction of the permanent magnet in the gap between two adjacent permanent magnets;

[0102] Radial leakage magnetic permeability of each permanent magnet is distributed along the radial direction of the permanent magnet in the gap between two adjacent permanent magnets and connected in series with the radial magnetic permeability of the air gap and the radial magnetic permeability of the soft magnetic back iron on both sides respectively.

[0103] The copper loss is determined by the total copper loss of each phase of the target motor.

[0104] Please continue reading. Figure 6 As shown, it is a schematic diagram of the optimized model of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention. In this embodiment, the optimized model includes:

[0105] ; ;

[0106] ; ;

[0107] ; ;

[0108] ; ;

[0109] ; ;

[0110] ;

[0111] Among them, G stt (i) represents the tangential magnetic permeability of the stator, G str (i) represents the stator radial permeability, G let (i) represents the tangential leakage permeability of the permanent magnet, G ler (i) represents the radial leakage permeability of the permanent magnet, G agt (i) represents the tangential permeability of the air gap, G agr (i) represents the radial permeability of the air gap, G rt (i) represents the tangential permeability of the soft magnetic back iron, G rr (i) represents the radial permeability of the soft magnetic back iron, G pm (i) represents the radial permeability of the permanent magnet, F pm (i) represents the magnetomotive force of the permanent magnet, μ0 represents the free permeability of the permanent magnet, and μ st μ represents the relative permeability of the stator and rotor. r R is the relative permeability of the permanent magnet; n is the number of layers; i is the layer number, i = 1, 2, 3...n; sto R is the outer radius of the stator; slotR is the radius of the stator slot bottom; s The inner radius of the stator; m R(θ) represents the outer radius of the permanent magnet. i θ is the radial inner radius of the curved profile formed by the irregular boundary of the i-th layer; θ is the circumferential angle at which the radial inner radius of the curved profile formed by the irregular boundary is located; L is the axial length of the stator; p is the number of motor pole pairs; α p B is the polar arc coefficient; r (i) represents the air gap magnetic flux density; Loss Cu Copper loss is measured in watts (W); H s2 Stator slot depth, in millimeters (mm), B s1 This refers to the stator slot width, in millimeters (mm). (B) s2 The width of the stator slot bottom is expressed in millimeters (mm).

[0112] It is understandable that the Equivalent Magnetoresistive Network (EMN) model is similar to a circuit. Therefore, the Equivalent Magnetoresistive Network (EMN) model is applicable to circuit analysis methods such as Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL). By using circuit analysis methods to construct an optimized model, the analysis difficulty of magnetic circuits can be greatly simplified.

[0113] Step S3: Determine the solution sampling range of the optimization model. The solution sampling range includes the radial inner radius sampling range, the stator slot depth sampling range, the stator slot opening width sampling range, and the stator slot bottom width sampling range.

[0114] In this embodiment of the invention, the sampling range of the radial inner radius is specifically R(θ). i ∈[18mm, 25mm], the stator slot depth sampling range is specifically H S2 The sampling range for stator slot width is specifically B, which is [8mm, 12mm]. S1 The sampling range for the stator slot bottom width is specifically B, which is [8mm, 10mm]. S2 ∈[15mm, 26mm].

[0115] It is understandable that the specific range of values ​​for solving the sampling range is determined based on the structural boundary conditions of the target motor, or based on the structural parameters of the motor pole array as the traditional configuration being optimized, which will not be elaborated further here.

[0116] Step S4: Solve the optimization model within the solution sampling range to obtain several sets of candidate solutions, wherein each set of candidate solutions includes several mutually matching radial inner radius and circumferential angle, electromagnetic torque and copper loss;

[0117] In this embodiment of the invention, after establishing the EMN model of the permanent magnet motor, the excitation quantities such as the magnetomotive force (MMF) from the armature winding and the permanent magnet are already determined. What needs to be solved is the magnetic potential of each node in the network. The equivalent magnetoresistive network model proposed in this invention contains 2a independent voltage sources and b nodes; the nodes determine the positions of various components (i.e., each magnetic permeability and each magnetomotive force) in the magnetoresistive network. Each component has a node at both ends, and the various components in the magnetoresistive network are connected through the relationships between the nodes. The relationship between the magnetic potential, magnetoresistive force, and magnetic flux of each node in the EMN model can be described by the following equation: Where matrix A is magnetic potential, matrix x is magnetic impedance, and matrix z is magnetic flux. The expressions for matrices A, x, and z are given by the following equations:

[0118] ;

[0119] ;

[0120] ;

[0121] In this matrix, matrix G is a symmetric matrix related to the equivalent magnetic permeability: each element on the main diagonal is equal to the sum of the conductivity of each reluctance connected to the potential node (its own conductivity), while the elements off the main diagonal are the negative conductivity of the reluctance connected to the corresponding node pair (mutual conductivity); submatrix C is a 0-1 matrix related to the connection between each node and the magnetomotive force source; submatrix D is a 0 matrix; submatrix p is the nodal magnetomotive force to be solved; submatrix v is the unknown magnetic flux through the magnetomotive force source; submatrix w is a 0 matrix; and submatrix e is the permanent magnet magnetomotive force (F) of the magnetic circuit. pm ); T represents the transpose of the matrix.

[0122] In summary, matrix A is full rank, and the nodal magnetomotive force can be obtained by the inverse transformation of matrix A. Based on this, the magnetic flux between adjacent nodes can be determined, thereby enabling the calculation of the air gap magnetic flux density. In this embodiment of the invention, the multi-objective optimization algorithm adopts NSGA-II, which will not be elaborated further.

[0123] Specifically, the formula for calculating the air gap magnetic flux density is:

[0124] ;

[0125] Among them, B r (i) represents the air gap magnetic flux density; x ib and x ia The air gap radial permeability G is respectively agr (i) Magnetomotive force at both ends, where ia is the index of each independent voltage source, ia=1,2,3...2a; ib is the index of each node, ib=1,2,3...b; Si For the radial magnetic permeability G through the air gap agr The cross-sectional area of ​​(i) is as follows:

[0126] ;

[0127] Furthermore, the magnetic flux linkage of a certain phase is obtained based on the distribution of the air gap magnetic flux density, specifically as follows:

[0128] ;

[0129] Where φ is the flux linkage of a certain phase, and the unit is Weber (Wb); B r The air gap magnetic flux density at various angles in a given phase is based on B. r (i) The mapping relationship with the angle is obtained, which will not be elaborated here.

[0130] Furthermore, the back electromotive force of a phase is obtained based on the magnetic flux linkage of that phase, specifically as follows:

[0131] ,

[0132] Where e is the back electromotive force, which is the derivative of the magnetic flux relative to time; t is time, in seconds (s).

[0133] Furthermore, based on the principle of electromagnetic power conversion, the electromagnetic torque is calculated as follows:

[0134] ;

[0135] Among them, T e ω is the electromagnetic torque, measured in N·m; ω is the mechanical angular velocity of the motor. Those skilled in the art will understand that ω is canceled out in specific calculations, and will not be elaborated further here; m is the number of phases of the motor; j is the phase number sequence of the motor, j=1,2,3...m; e j Let i be the back electromotive force of phase j; j Let be the current in the j-th phase;

[0136] The above calculation process can be solved by computer, and will not be described in detail here.

[0137] Please continue reading. Figures 7-10 As shown, these are, respectively, the Pareto front view of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention, the left view of the Pareto front view of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention, the right view of the Pareto front view of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention, and the top view of the Pareto front view of the magnetic pole array of the magnetic circuit reconfigurable motor of the present invention.

[0138] Step S5: Optimize several sets of candidate solutions according to the optimization objectives and desired operating conditions to obtain optimized solutions. The optimization objectives include maximizing the torque density, maximizing the torque-to-inertia ratio, maximizing the permanent magnet utilization efficiency, and minimizing copper losses of the target motor.

[0139] Specifically, step S5 includes:

[0140] Step S51: Determine the torque output characteristics of each candidate solution based on the model basic parameters and optimization basic parameters of the target motor and the electromagnetic torque of each candidate solution.

[0141] Step S52: Select the torque output characteristics and the corresponding copper loss according to the optimization objective and the desired operating condition to obtain the optimized solution.

[0142] Specifically, the torque output characteristics include torque density, torque-to-inertia ratio, and permanent magnet utilization rate.

[0143] Specifically, the torque density is the ratio of electromagnetic torque to the effective mass of the motor, the torque-inertia ratio is the ratio of electromagnetic torque to rotor inertia, and the permanent magnet utilization rate is the ratio of electromagnetic torque to permanent magnet mass.

[0144] It is understandable that torque output is proportional to current, while winding copper loss increases with the square of current. This leads to an inherent trade-off between pursuing high torque and minimizing copper loss. Therefore, in this invention, the optimization objectives are defined as: maximizing torque density, maximizing torque-to-inertia ratio, maximizing permanent magnet utilization efficiency, and minimizing motor copper loss.

[0145] It is understandable that, based on the candidate solutions, it can be seen that the various items of the optimization objective are mutually restrictive. Therefore, according to the expected operating conditions in actual production, the candidate solutions are selected to obtain the optimal solution under specific motor basic parameters and specific expected operating conditions.

[0146] In this embodiment of the invention, the expression for torque density is specifically as follows:

[0147] ;

[0148] in,

[0149] ,

[0150] ,

[0151] ,

[0152] ,

[0153] Where, ρ T T is the torque density; e V represents electromagnetic torque, measured in N·m. Cu The winding volume is expressed in cubic millimeters (mm). 3 ); V Fet The volume of the stator is expressed in cubic millimeters (mm). 3 ); V Fer The volume of the soft magnetic back iron is expressed in cubic millimeters (mm). 3 ); V pm The volume of the permanent magnet is expressed in cubic millimeters (mm). 3 ).

[0154] In this embodiment of the invention, the expression for the torque-inertia ratio is specifically as follows:

[0155] ;

[0156] in,

[0157] ;

[0158] Among them, A r The torque-to-inertia ratio; m r The effective mass of the rotor is expressed in kilograms (kg).

[0159] It is understandable that the torque-to-inertia ratio is an indicator for measuring the inherent dynamic response capability of a motor, and it directly reflects the motor's response speed.

[0160] In this embodiment of the invention, the expression for the utilization rate of the permanent magnet is specifically as follows:

[0161] ,

[0162] Where, δ pm This refers to the utilization rate of permanent magnets.

[0163] It is understandable that rare earth permanent magnets are an indispensable key component in electric motors, playing a decisive role in determining output performance. However, their high cost makes it particularly important to minimize the amount of magnets used while ensuring output torque. Therefore, the utilization efficiency of permanent magnets is defined as the ratio of electromagnetic torque to the mass of permanent magnets.

[0164] In this embodiment of the invention, the final Palito front is obtained through the above multi-objective optimization process, and a suitable design point is selected on the Palito front according to the required operating conditions, thus obtaining the optimized solution.

[0165] Step S6: Based on the optimized solution, determine the irregular boundary and stator slot size data of the target motor.

[0166] The irregular boundary is a continuously changing curved profile formed by the contact surface between the permanent magnet and the soft magnetic back iron in the motor magnetic pole array. The curved profile has a corresponding radial inner radius at different circumferential angles. The stator slot size data includes the stator slot depth, stator slot opening width, and stator slot bottom width.

[0167] In this embodiment of the invention, the optimized solution includes the radial inner radius and the corresponding circumferential angle of a plurality of permanent magnets, the number of which is (n+1); these radial inner radii and the corresponding circumferential angles of the permanent magnets are fitted into a curve profile, thereby obtaining the irregular boundary formed by the radial contact surface of the permanent magnets and the soft magnetic back iron. Example 1

[0168] In traditional configuration motor pole arrays, the boundaries between the permanent magnet and the soft magnetic back iron are regular, that is, the radius R (θ) inside the permanent magnet is a constant value and does not change with the angle θ. Its parameters are shown in Table 1. Example 2

[0169] The magnetic pole array of the reconfigurable magnetic circuit motor is determined according to the design method of the present invention, and its number of layers is 10; its dimensional parameters are shown in Table 1, and the dimensions of its irregular boundary are shown in Table 2.

[0170] The magnetic pole array of the reconfigurable magnetic circuit motor is determined according to the design method of the present invention, and its number of layers is 10; its dimensional parameters are shown in Table 1, and the dimensions of its irregular boundary are shown in Table 2.

[0171] Table 1. Dimensional parameters of magnetic pole arrays for conventional configuration motors and magnetic circuit reconfiguration motors.

[0172]

[0173] Table 2. Irregular boundary dimension parameters of the magnetic pole array of the magnetic circuit reconfiguration motor

[0174]

[0175] Please see Figures 11-15 Through intuitive comparison of the data, it is clear that the invention designs an irregular boundary between the permanent magnet and the soft magnetic back iron to form a continuously changing curved profile, so that the radial inner diameter is dynamically adjusted with the circumferential angle, thus reconstructing the magnetic circuit distribution of the magnetic pole array.

[0176] Please see Figures 11-12As shown, the magnitude of the fundamental component of the air gap flux density is positively correlated with the electromagnetic torque output of the motor. However, the high-order harmonic content in the air gap flux density leads to torque fluctuations, increased stator core losses, and other adverse effects. Compared with the traditional structure, the proposed magnetic circuit reconstruction structure shows that the peak value of the air gap flux density is higher. According to Fourier decomposition, the fundamental component of the air gap flux density of the magnetic circuit reconstruction structure reaches 0.97 Tesla (T), which is 10% higher than the 0.88 Tesla (T) of the traditional structure. In addition, the magnetic circuit reconstruction structure reduces the third and fifth harmonics by 17% and 19%, respectively, and the seventh harmonic is nearly six times lower than that of the traditional structure.

[0177] Please see Figures 13-15 As shown, the magnitude of the fundamental component of the back electromotive force (EMF) is positively correlated with the electromagnetic torque output of the motor. Compared with the traditional structure, the proposed magnetic circuit reconfiguration structure exhibits a higher peak back EMF. According to Fourier decomposition, the fundamental component of the air gap magnetic flux density in the magnetic circuit reconfiguration structure reaches 65V, which is 10% higher than the 58V of the traditional structure. In terms of output torque, the magnetic circuit reconfiguration structure delivers 9.5Nm, while the traditional configuration delivers 8.7Nm, representing an improvement of nearly 10%.

[0178] This invention improves the contact boundary between the permanent magnet and the soft magnetic material from the traditional straight / stepped shape to an irregularly shaped boundary with a specific function. Because the improved boundary shape makes the air gap magnetic field distribution closer to an ideal sine wave, the following effects are achieved: the total harmonic distortion of the air gap magnetic field is greatly reduced, ultimately leading to a significant reduction in torque pulsation and stator iron loss. The fundamental amplitude of the air gap magnetic field is increased, resulting in improved torque with the same amount of permanent magnet.

[0179] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine, characterized in that, The method comprises the following steps: Step S1, obtaining model basic parameters and optimization basic parameters of a target motor, wherein the model basic parameters comprise an outer radius of a permanent magnet, an inner radius of a stator, an outer radius of the stator, a bottom radius of a stator slot, an axial length of the stator, a slot fullness of the stator, a winding number of turns, a stator tooth pitch angle, a motor phase number, a motor pole pair number, a pole arc coefficient and an input current, and the optimization basic parameters comprise an inner radius of a soft magnetic back iron, a copper material density, a permanent magnet material density and a soft magnetic back iron material density; Step S2, constructing an optimization model of a magnetic circuit reconfiguration motor magnetic pole array based on the model basic parameters and magnetic permeability basic parameters of the target motor, wherein the magnetic permeability basic parameters comprise a vacuum magnetic permeability of the permanent magnet, a relative magnetic permeability of the stator and the rotor and a relative magnetic permeability of the permanent magnet; Step S3, determining a solution sampling range of the optimization model, wherein the solution sampling range comprises a radial inner radius sampling range, a stator slot depth sampling range, a stator slot opening width sampling range and a stator slot bottom width sampling range; Step S4, performing a solution based on the optimization model in the solution sampling range to obtain a plurality of groups of candidate solutions, wherein each group of the candidate solutions comprises a plurality of mutually matched radial inner radii and circumferential angles, electromagnetic torques and copper losses; Step S5, performing optimization on the plurality of groups of candidate solutions according to optimization targets and expected working conditions to obtain an optimization solution, wherein the optimization targets comprise maximizing a torque density, maximizing a torque inertia ratio, maximizing a permanent magnet utilization efficiency and minimizing a copper loss of the target motor; Step S6, determining a special-shaped boundary and stator slot size data of the target motor according to the optimization solution, wherein the special-shaped boundary is a continuously changing curve profile formed by a contact surface of the permanent magnet and the soft magnetic back iron in the motor magnetic pole array, the curve profile has a corresponding radial inner radius at different circumferential angles, and the stator slot size data comprises a stator slot depth, a stator slot opening width and a stator slot bottom width. The step S2 comprises:

2. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 1, characterized in that, Step S21, obtaining a solution domain structure model of a single pair of adjacent permanent magnets of the target motor based on the model basic parameters of the target motor; Step S22, performing a finite number of layers on the solution domain structure model based on a main magnetic flux path of a single pair of magnetic poles to obtain a solution domain layered model; Step S23, obtaining the optimization model according to the solution domain layered model and the magnetic permeability basic parameters, wherein the optimization model is a solution domain equivalent magnetic resistance network of the solution domain layered model. The optimization model comprises:

3. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 2, characterized in that, each stator tangential magnetic permeability distributed along a tangential direction of the stator; each stator radial magnetic permeability distributed along a radial direction of the stator; each air gap tangential magnetic permeability distributed along a tangential direction of an air gap and corresponding to each stator tangential magnetic permeability in series; each air gap radial magnetic permeability distributed along a radial direction of the air gap; each permanent magnet radial magnetic permeability distributed along a radial direction of a permanent magnet in two adjacent permanent magnets and corresponding to each air gap tangential magnetic permeability in series; each permanent magnet electromotive force distributed along a radial direction of the permanent magnet in two adjacent permanent magnets and located between the permanent magnet radial magnetic permeability and the air gap radial magnetic permeability; ​ Each soft magnetic back tangential magnetic permeance distributed along the tangential direction of the soft magnetic back and corresponding to each of the radial magnetic permeances of the two adjacent permanent magnets in series; Each soft magnetic back radial magnetic permeance distributed along the radial direction of the soft magnetic back; Each permanent magnet tangential leakage magnetic permeance distributed along the tangential direction of the permanent magnet in the interval gap between the two adjacent permanent magnets; Each permanent magnet radial leakage magnetic permeance distributed along the radial direction of the permanent magnet in the interval gap between the two adjacent permanent magnets and in series with the radial magnetic permeance of the air gap and the radial magnetic permeance of the soft magnetic back on both sides; The copper loss determined by the total copper loss of each phase of the target motor.

4. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 3, characterized in that, In the step S22, the way of finite times of layering is to divide the cross section of the permanent magnet, the soft magnetic back, the stator and the air gap into n layers of rectangular frames based on the main magnetic flux path, Wherein, n is a positive integer, the first layer of the rectangular frame is located at the main magnetic flux path of the permanent magnet radial section at the center, and the n layer of the rectangular frame is located at the main magnetic flux path of the permanent magnet radial section close to the edge of the adjacent permanent magnet; The width of the rectangular frame of each permanent magnet layering model along the circumferential direction of the permanent magnet is equal, each layer of the permanent magnet layering model has a corresponding circumferential angle, and the value range of n is [10, 100].

5. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 4, characterized in that, The main magnetic flux path is along the clockwise direction, starting from the N pole of the permanent magnet, passing through the soft magnetic back, the N pole of the adjacent permanent magnet and the air gap, the stator in turn, and finally passing through the air gap into the S pole of the permanent magnet again.

6. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 5, characterized in that, In the step S23, the optimization model is constructed along each of the rectangular frames in the layering model of the solution domain. For the optimization model on a single rectangular frame, the permanent magnet radial magnetic permeance, the soft magnetic back tangential magnetic permeance, the permanent magnet radial magnetic permeance of the adjacent permanent magnet, the permanent magnet magnetic motive force of the adjacent permanent magnet, the air gap radial magnetic permeance, the stator radial magnetic permeance, the stator tangential magnetic permeance, the stator radial magnetic permeance, the air gap radial magnetic permeance and the permanent magnet magnetic motive force are arranged in turn in clockwise direction.

7. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 6, characterized in that, The part of the rectangular frame of a single permanent magnet layering model located in the permanent magnet is trapezoidal.

8. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 2, characterized in that, The step S5 includes: Step S51, determining the torque output characteristic of each candidate solution according to the model basic parameters and the optimization basic parameters of the target motor and the electromagnetic torque of each candidate solution; Step S52, selecting the torque output characteristic and the corresponding copper loss according to the optimization target and the expected working condition to obtain the optimization solution.

9. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 8, characterized in that, The torque output characteristic includes torque density, torque inertia ratio and permanent magnet utilization rate.

10. The method of designing a magnetic pole array of a magnetic circuit reconfigurable electric machine according to claim 9, wherein, The torque density is the ratio of electromagnetic torque to effective mass of the motor, the torque inertia ratio is the ratio of electromagnetic torque to rotor inertia, and the permanent magnet utilization rate is the ratio of electromagnetic torque to permanent magnet mass.

Images