A magnetic circuit modeling method for a dual-stator single-rotor axial permanent magnet motor

Abstract

The invention discloses a magnetic circuit modeling method for a double-stator single-rotor axial permanent magnet motor, belonging to the field of motor optimization design; a magnetic circuit modeling method for a double-stator single-rotor axial permanent magnet motor comprises: defining geometric parameters and material parameters of motor components; dividing the nodes of the motor components, and expressing the magnetic resistance and magnetomotive force of each component according to the geometric parameters and material parameters of the components to construct a magnetic network model; based on a general magnetic network model, considering the leakage flux in the stator slot, the leakage flux of adjacent permanent magnets through long pole shoes, and the leakage flux at the end position of the stator winding; defining the connection mode between each unit of the motor; according to different rotor positions corresponding to different times, obtaining a complete magnetic circuit model under different rotor positions; based on the complete magnetic circuit model, performing nonlinear iterative calculation on the magnetic permeability of the stator core to obtain the final convergence result of the magnetic circuit.

Description

Technical Field

[0001] The present invention belongs to the field of motor optimization design, and in particular relates to a magnetic circuit modeling method for a dual-stator single-rotor axial permanent magnet motor. Background Art

[0002] Permanent magnet synchronous motors have been greatly developed in the past few decades. There are many types of radial flux permanent magnet motors and they have been widely used in various fields. However, in some cases, radial flux permanent magnet motors cannot be used due to their long axial length. For example, wind turbines, flywheel energy storage, automotive applications, and other applications with axial space limitations. The magnetic flux direction of axial permanent magnet motors is along the axial direction, which not only has a large magnetic energy density, but also a large space for energy exchange. Therefore, the torque density of axial permanent magnet motors is improved compared to radial permanent magnet motors.

[0003] The most accurate method for calculating the performance of axial permanent magnet motors is 3D finite element analysis. The 3D finite element method is based on the accurate geometric model of the motor and can calculate the spatial magnetic field of complex structures, but it requires too much computing time. The computing time can be greatly reduced by expanding the axial motor into a 2D linear motor model. However, this method usually ignores the influence of leakage flux at the end position of the stator winding, and as the load increases, the average electromagnetic torque error with the 3D finite element analysis will also increase.

[0004] The magnetic circuit method can design a special parameter magnetic circuit for a certain type of motor, and can quickly predict its performance in the early stages of motor design. In addition, the preliminary optimization design of the motor can be achieved by the magnetic circuit method. The existing magnetic circuit method for the dual-stator single-rotor axial permanent magnet motor generally does not consider the leakage flux at the end position of the stator winding, and does not predict the performance when the motor load changes, which has certain shortcomings. Therefore, the magnetic circuit method modeling for the dual-stator single-rotor axial permanent magnet motor still has a high research value. Summary of the invention

[0005] In view of the deficiencies in the prior art, an object of the present invention is to provide a method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for modeling a magnetic circuit of a dual-stator single-rotor axial permanent magnet motor comprises the following steps:

[0008] Define the geometric parameters and material parameters of the motor components;

[0009] Divide the nodes of the motor components, and represent the magnetic resistance and magnetomotive force of each component according to the geometric parameters and material parameters of the components to build a magnetic network model;

[0010] Based on the magnetic network model, the magnetic flux leakage in the stator slots, the magnetic flux leakage of adjacent permanent magnets through the long pole shoes, and the magnetic flux leakage at the end of the stator winding are considered; the connection method between the motor units is defined; according to the different rotor positions corresponding to different times, the complete magnetic circuit model under different rotor positions is obtained;

[0011] Based on the complete magnetic circuit model, the magnetic permeability of the stator core is calculated nonlinearly and iteratively to obtain the final convergence result of the magnetic circuit.

[0012] Further, the geometric parameters of the motor components include: geometric structural parameters, geometric positions, and air gaps of the stator, rotor, and windings;

[0013] The material parameters of the motor components include: electromagnetic properties of stator and rotor materials, and the electromagnetic properties include magnetic permeability and magnetization intensity.

[0014] Furthermore, the node division of the motor components includes dividing the nodes of the stator, the rotor and the air gap.

[0015] Further, the magnetic resistance is divided into rectangular columnar magnetic resistance, rectangular and semicircular combined columnar magnetic resistance and annular columnar magnetic resistance;

[0016] Among them, for the rectangular columnar magnetic resistance, the magnetic resistance R1 in its magnetic flux direction can be expressed as,

[0017]

[0018] Where L represents the magnetic path length of a unit of the motor in the direction of the magnetic flux, μ0 is the vacuum permeability, and μ r is the relative magnetic permeability of a motor component, and S represents the area passed by the magnetic flux path;

[0019] For the columnar magnetic resistance of the combination of rectangle and semicircle, the magnetic resistance R2 in the direction of its magnetic flux can be expressed as:

[0020]

[0021] Among them, R h Indicates the radius of the semicircle, L depth represents the thickness of the linear motor; x represents the integral variable of the arc radius;

[0022] L depth It can be expressed as:

[0023] L depth =R o -R i (3)

[0024] Where R i , R o are the inner and outer diameters of the axial motor, respectively;

[0025] For annular cylindrical reluctance, the reluctance R3 in the direction of its magnetic flux can be expressed as,

[0026]

[0027] Among them, R m , R n are the inner and outer diameters of the ring respectively, and θ represents the arc swept by the ring.

[0028] Furthermore, the axial magnetomotive force F of the three-phase armature magnetomotive force abc It can be expressed as:

[0029]

[0030] Among them, N c Indicates the number of coil turns, i a 、i b 、i c Respectively represent the instantaneous values ​​of the three-phase currents;

[0031] The axial magnetomotive force F of the permanent magnet magnetomotive force pm It can be expressed as:

[0032] F pm =H c H pm (6)

[0033] Among them, H c Represents the magnetization intensity of the permanent magnet, H pm Represents the axial length of the permanent magnet.

[0034] Furthermore, the nonlinear iterative calculation step of the stator core magnetic permeability includes:

[0035] S41, initialize the parameters of the equivalent magnetic circuit, give the initial magnetic permeability, and calculate the initial magnetic resistance of the stator core; it should be noted that;

[0036] S42, performing magnetic circuit calculation to obtain the magnetic flux Φ at each position;

[0037] S43, export to the work area to calculate the magnetic flux density B at each position, and obtain a new magnetic permeability through the BH curve of common materials;

[0038] S44, calculate the relative error between the current magnetic permeability and the magnetic permeability of the last iteration. If the relative error is greater than the given error δ, update the magnetic permeability and continue to iterate until the relative error is less than δ, that is, the calculation result converges. At this time, record the current magnetic flux and magnetic flux density, and the calculation of this network iteration model of the motor is completed.

[0039] Furthermore, the iterative expression of the magnetic permeability is:

[0040] μ k =p1μ k +p2μ k-1 (7)

[0041] In the formula, μ k and μ k-1 are the current magnetic permeability and the magnetic permeability of the previous iteration respectively, p2 and p1 are the current magnetic permeability coefficient and the magnetic permeability coefficient after the previous iteration, p1+p2=1.

[0042] Furthermore, the relative error convergence judgment expression is:

[0043]

[0044] A magnetic circuit modeling system for a dual-stator single-rotor axial permanent magnet motor, comprising:

[0045] Parameter definition module: defines the geometric parameters and material parameters of motor components;

[0046] Magnetic network model building module: divide the nodes of the motor components, represent the magnetic resistance and magnetomotive force of each component according to the geometric parameters and material parameters of the components, and build a magnetic network model;

[0047] Magnetic circuit model construction module: Based on the magnetic network model, the magnetic flux leakage in the stator slot, the magnetic flux leakage of adjacent permanent magnets through the long pole shoes, and the magnetic flux leakage at the end of the stator winding are considered; the connection method between the motor units is defined; according to the different rotor positions corresponding to different times, the complete magnetic circuit model under different rotor positions is obtained;

[0048] And, iterative calculation module: based on the complete magnetic circuit model, the magnetic permeability of the stator core is calculated nonlinearly to obtain the final convergence result of the magnetic circuit.

[0049] A computer storage medium stores a readable program, which can execute the above modeling method when the program is run.

[0050] Beneficial effects of the present invention:

[0051] 1. The magnetic circuit modeling method of the double-stator single-rotor axial permanent magnet motor provided by the present invention can efficiently establish a magnetic network model of this type of motor;

[0052] 2. Using the double-stator single-rotor axial permanent magnet motor magnetic circuit modeling method provided by the present invention, a magnetic network model of this type of motor can be established in the early stage of motor design to quickly obtain the main performance of the motor, which is intuitive and easy to implement;

[0053] 3. Using the double-stator single-rotor axial permanent magnet motor magnetic circuit modeling method provided by the present invention, the motor magnetic network model established takes into account the leakage magnetic circuit at the end position of the stator winding, and can obtain the average electromagnetic torque of the motor under different load conditions. It is more accurate than the two-dimensional finite element model equivalent to the linear motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 is a flow chart of the modeling method of the present invention;

[0056] Figure 2 This is a topological structure diagram of a 24-slot, 20-pole, double-stator, single-rotor axial permanent magnet motor in the present invention;

[0057] Figure 3 is a stator magnetic network model diagram of the present invention;

[0058] Figure 4 is a rotor magnetic network model diagram of the present invention;

[0059] Figure 5 is an air gap division model diagram under the first rotor position of the present invention;

[0060] Figure 6 is an air gap division model diagram under the second rotor position of the present invention;

[0061] Figure 7 is an air gap division model diagram under the third rotor position of the present invention;

[0062] Figure 8 It is the leakage magnetic model diagram at the end position of the stator winding;

[0063] Fig. 9 It is a complete motor magnetic network model diagram of the present invention;

[0064] Fig.10 It is a comparison of the axial air gap flux density of the magnetic circuit method and the equivalent two-dimensional finite element of a one-layer linear motor under no-load conditions when the rotor is at 0 electrical angle, and its harmonic analysis result diagram;

[0065] Fig.11 It is a comparison of the axial air gap flux density of the magnetic circuit method of the present invention and the equivalent two-dimensional finite element of a one-layer linear motor under no-load conditions, and its harmonic analysis result diagram;

[0066] Fig.12 It is a comparison chart of the no-load phase flux curve and its harmonic analysis results between the magnetic circuit method, the equivalent two-dimensional finite element and three-dimensional finite element analysis of a one-layer linear motor when the motor is running at 750 rpm;

[0067] Fig.13 It is a comparison chart of no-load reverse potential curves and harmonic analysis results between the magnetic circuit method, the equivalent two-dimensional finite element and three-dimensional finite element analysis of a single-layer linear motor when the motor is running at 750 rpm;

[0068] Fig.14 It is the average electromagnetic torque comparison curve of the magnetic circuit method, the two-dimensional finite element equivalent to a one-layer linear motor, and the three-dimensional finite element, as well as the relative error curve between the magnetic circuit method and the three-dimensional finite element results when the slot current density is less than 30 amperes per square millimeter. DETAILED DESCRIPTION

[0069] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] like Figure 2 As shown, the components of the analyzed motor are typical common components in the motor, such as the stator, rotor, and winding. The rotor is a permanent magnet embedded in a non-magnetic material. There is an air gap between the stator and the rotor. The motor uses a three-phase symmetrical AC winding. In addition, the technology involved in the present invention is not only applicable to this type of winding, but also to single-phase, multi-phase, and asymmetrical motor windings.

[0071] In addition, the technology involved in the present invention is not only applicable to this type of motor, but also applicable to all double-stator single-rotor axial permanent magnet motor topologies in which the permanent magnet and stator widths are the same.

[0072] like Figure 1 As shown, a method for modeling a magnetic circuit of a dual-stator single-rotor axial permanent magnet motor includes the following steps:

[0073] S1, define the geometric parameters and material parameters of the motor components;

[0074] The geometric parameters of motor components include: geometric structural parameters, geometric position, air gap, etc. of stator, rotor, and winding;

[0075] The material parameters of motor components include: electromagnetic properties of stator and rotor materials, including magnetic permeability, magnetization intensity, etc.;

[0076] The middle section of the axial motor is unfolded into a linear motor to obtain the geometric parameters and material parameters of the linear motor. The length and area in the magnetic flux direction are calculated based on the geometric parameters of the stator, rotor and air gap of the linear motor.

[0077] S2, dividing the nodes of the motor components, representing the magnetic resistance and magnetomotive force of each component according to the geometric parameters and material parameters of the components, so as to construct a magnetic network model;

[0078] The node division of motor components includes the division of stator, rotor and air gap nodes, which is used to define the number of nodes of the magnetic network model and divide the motor into appropriate units.

[0079] The magnetic resistance is divided into rectangular columnar magnetic resistance, rectangular and semicircular combination columnar magnetic resistance and annular columnar magnetic resistance;

[0080] Among them, for the rectangular columnar magnetic resistance, the magnetic resistance R1 in its magnetic flux direction can be expressed as,

[0081]

[0082] Where L represents the magnetic path length of a unit of the motor in the direction of the magnetic flux, μ0 is the vacuum permeability, and μ r is the relative magnetic permeability of a motor component, and S represents the area passed by the magnetic flux path;

[0083] For the columnar magnetic resistance of the combination of rectangle and semicircle, the magnetic resistance R2 in the direction of its magnetic flux can be expressed as:

[0084]

[0085] Among them, R h Indicates the radius of the semicircle, L depth represents the thickness of the linear motor; x represents the integral variable of the arc radius;

[0086] L depth It can be expressed as:

[0087] L depth =R o -R i (3)

[0088] Where R i , R o are the inner and outer diameters of the axial motor, respectively;

[0089] For annular cylindrical reluctance, the reluctance R3 in the direction of its magnetic flux can be expressed as,

[0090]

[0091] Among them, R m , Rn are the inner and outer diameters of the ring, respectively, and θ represents the arc swept by the ring;

[0092] For the three-phase armature magnetomotive force, its axial magnetomotive force F abc It can be expressed as:

[0093]

[0094] Among them, N c Indicates the number of coil turns, i a 、i b 、i c Respectively represent the instantaneous values ​​of the three-phase currents;

[0095] For permanent magnet magnetomotive force, its axial magnetomotive force F pm It can be expressed as:

[0096] F pm =H c H pm (6)

[0097] Among them, H c Represents the magnetization intensity of the permanent magnet, H pm Represents the axial length of the permanent magnet.

[0098] In this embodiment, the motor is symmetrical in the axial direction, so a single-sided stator and rotor can be used for modeling; the magnetic circuit model of the stator teeth is as follows: Figure 3 As shown; where R y is the magnetic resistance of the stator yoke, R t is the reluctance of the stator teeth, R ss is the magnetic resistance between the two pole shoes, R s is the leakage magnetic resistance in the slot. sh is the magnetic resistance of the pole shoe, and the bottom of the tooth is composed of R tt Modeling, F abc is the armature magnetomotive force, F pm is the magnetomotive force of the permanent magnet.

[0099] The magnetic network model of a permanent magnet is as follows Figure 4 As shown in the figure, there is end leakage at the inner and outer diameters of the permanent magnet. Air gap division is a key part of magnetic circuit design. Due to the existence of pole shoes, the air gap utilization range is increased. First, the basic air gap reluctance framework is constructed according to the relative position of the permanent magnet and the stator, as well as the facing area. Figures 5 to 7 As shown, except for R ap (circular air gap leakage resistance between adjacent permanent magnets) and R pl In addition to the parallelogram air gap leakage resistance between adjacent permanent magnets, the air gap flux path is considered to be axial with high accuracy. The stator winding end position leakage model is as follows: Figure 8As shown, according to the electromagnetic field theoretical analysis and finite element magnetic field calculation results, the leakage magnetic resistance at the end of the stator winding is defined as two annular cylindrical magnetic resistances, which can be regarded as being in parallel with the leakage magnetic resistance in the slot.

[0100] S3, based on the magnetic circuit division of S2 and the magnetic resistance or magnetomotive force of each component, the leakage flux in the stator slot, the leakage flux of the adjacent permanent magnets through the long pole shoes and the leakage flux at the end of the permanent magnet are considered respectively. Since the end leakage flux is obvious under heavy load, the leakage magnetic circuit at the end position of the stator winding is modeled to simulate the actual magnetic circuit under heavy load to define the connection mode between the various units of the motor; according to different rotor positions corresponding to different times, the complete magnetic circuit model under different rotor positions is obtained;

[0101] In this embodiment, the complete magnetic circuit model is as follows: Fig. 9 As shown in the figure, the magnetic resistance, number of nodes and connection mode of the model are closely related to the rotor position, and the magnetic circuit varies with the rotor position. Since the dual-stator single-rotor axial permanent magnet motor example is a 24-slot / 20-pole structure, the magnetic circuit topology is the same (the armature magnetomotive force is different) every time the rotor rotates 3 mechanical degrees (30 electrical degrees); in this embodiment, the magnetic circuit topology under two positions is established, R el The existence or non-existence of (stator winding end position leakage magnetic resistance) reflects whether the influence of end magnetic flux leakage is considered.

[0102] S4, based on the complete magnetic circuit model obtained in S3, a nonlinear iterative calculation is performed on the magnetic permeability of the stator core in the magnetic circuit to obtain the final convergence result of the magnetic circuit;

[0103] In the magnetic circuit model of the double-stator axial permanent magnet motor, the magnetic permeability of the stator core is nonlinear; in order to obtain the final convergence result of the magnetic circuit, nonlinear iterative calculation is required;

[0104] The steps of nonlinear iterative calculation include:

[0105] S41, initialize the parameters of the equivalent magnetic circuit, give the initial magnetic permeability, and calculate the initial magnetic resistance of the stator core; it should be noted that the initial magnetic permeability should be as close to the actual value as possible to reduce the number of iterations;

[0106] S42, performing magnetic circuit calculation to obtain the magnetic flux Φ at each position;

[0107] S43, export to the work area to calculate the magnetic flux density B at each position, and obtain a new magnetic permeability through the BH curve of common materials;

[0108] S44, calculate the relative error between the current magnetic permeability and the magnetic permeability of the last iteration. If the relative error is greater than the given error δ, update the magnetic permeability and continue to iterate until the relative error is less than δ, that is, the calculation result converges. At this time, record the current magnetic flux and magnetic flux density, and the calculation of this network iteration model of the motor is completed.

[0109] The magnetic permeability can be iterated by:

[0110] μ k =p1μ k +p2μ k-1 (7)

[0111] In the formula, μ k and μ k-1 are the current magnetic permeability and the magnetic permeability of the last iteration, p2 and p1 are the current magnetic permeability coefficient and the magnetic permeability coefficient after the last iteration, p1+p2=1; the larger p1 is, the better the convergence is and the slower the convergence speed is;

[0112] The relative error convergence judgment expression is:

[0113]

[0114] Based on the established magnetic circuit model of the double-stator single-rotor axial permanent magnet motor taking into account the magnetic leakage at the end of the stator winding, the average electromagnetic torque of the motor corresponding to different slot current densities is calculated with reference to the operating conditions of the motor, and compared with the finite element results.

[0115] like Fig.10 , 11 As shown in (a) and (b), under no-load conditions, the axial air gap flux of the rotor at the positions of 0 electrical angle and 15 electrical angle is compared using the magnetic circuit method and the equivalent two-dimensional finite element of a one-layer linear motor. According to the waveform, it can be seen that there is a certain error in the no-load air gap flux of some positions between the magnetic circuit method and the finite element results of the present invention, but the accuracy of the amplitude of each order harmonic is relatively high.

[0116] like Fig.12 As shown, Fig.12 (a) and (b) are comparison diagrams of no-load phase flux curves and harmonic analysis results between the magnetic circuit method, the equivalent two-dimensional finite element analysis of a one-layer linear motor, and the three-dimensional finite element analysis when the motor runs at 750 rpm. The fundamental amplitude error is about 4.3%.

[0117] like Fig.13 As shown, Fig.13(a) and (b) are the comparison diagrams of the no-load back electromotive force curves and harmonic analysis results of the magnetic circuit method, the equivalent two-dimensional finite element analysis of a single-layer linear motor, and the three-dimensional finite element analysis when the motor is running at 750 rpm. It can be concluded that the fundamental amplitude error between the magnetic circuit method and the three-dimensional finite element analysis results is about 4.0%, and the back electromotive force harmonic amplitude calculated by the magnetic circuit method is slightly larger. Fig.12 , 13 It can be seen that the present invention can predict the no-load performance of the motor more accurately.

[0118] like Fig.14 As shown, Fig.14 It is the average electromagnetic torque comparison curve of the magnetic circuit method, the two-dimensional finite element equivalent to a one-layer linear motor, and the three-dimensional finite element, as well as the relative error curve between the first two and the three-dimensional finite element results. Fig.14 It can be seen that when the slot current density is within 30 amperes per square millimeter, the average electromagnetic torque error between the magnetic circuit method and the three-dimensional finite element is basically controlled within 5%. Fig.14 It can be seen that the present invention still has a relatively accurate torque prediction capability under the condition of high load of the dual-stator single-rotor axial motor.

[0119] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0120] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor, characterized in that: The following steps are involved: Define the geometric parameters and material parameters of the motor components; Divide the nodes of the motor components, and represent the magnetic resistance and magnetomotive force of each component according to the geometric parameters and material parameters of the components to build a magnetic network model; Based on the magnetic network model, the connection mode between the motor units is defined by considering the magnetic flux leakage in the stator slots, the magnetic flux leakage of the adjacent permanent magnets through the long pole shoes, and the magnetic flux leakage at the end of the stator winding. The complete magnetic circuit model under different rotor positions is obtained according to the different rotor positions corresponding to different times. Based on the complete magnetic circuit model, the magnetic permeability of the stator core in the magnetic circuit is calculated nonlinearly iteratively to obtain the final convergence result of the magnetic circuit.

2. A method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor according to claim 1, characterized in that: The geometric parameters of the motor components include: geometric structural parameters, geometric positions, and air gaps of the stator, rotor, and windings; The material parameters of the motor components include: electromagnetic properties of stator and rotor materials, and the electromagnetic properties include magnetic permeability and magnetization intensity.

3. The method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor according to claim 1 is characterized in that: The node division of the motor components includes dividing the nodes of the stator, the rotor and the air gap.

4. The method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor according to claim 1, characterized in that: The magnetic resistance is divided into rectangular columnar magnetic resistance 、 A combination of rectangular and semicircular columnar magnetic resistance and annular columnar magnetic resistance; Among them, the magnetic resistance R1 in the direction of the rectangular columnar magnetic resistance flux can be expressed as, Where L represents the magnetic path length of a unit of the motor in the direction of the magnetic flux, μ0 is the vacuum permeability, and μ r is the relative magnetic permeability of a motor component, and S represents the area passed by the magnetic flux path; The magnetic resistance R2 in the direction of the columnar magnetic resistance flux of the combination of rectangle and semicircle can be expressed as, Among them, R h Indicates the radius of the semicircle, L depth represents the thickness of the linear motor, and x represents the integral variable of the arc radius; L depth It can be expressed as: L depth =R o -R i (3) Where R i , R o are the inner and outer diameters of the axial motor, respectively; The magnetic resistance R3 in the direction of the annular cylindrical magnetic resistance flux can be expressed as: Among them, R m , R n are the inner and outer diameters of the ring respectively, and θ represents the arc swept by the ring.

5. The method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor according to claim 1, characterized in that: Axial magnetomotive force F of three-phase armature magnetomotive force abc It can be expressed as: Among them, N c Indicates the number of coil turns, i a 、i b 、i c Respectively represent the instantaneous values ​​of the three-phase currents; The axial magnetomotive force F of the permanent magnet magnetomotive force pm It can be expressed as: F pm =H c H pm (6) Among them, H c Represents the magnetization intensity of the permanent magnet, H pm Represents the axial length of the permanent magnet.

6. The method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor according to claim 1, characterized in that: The nonlinear iterative calculation step of the stator core magnetic permeability includes: S41, initializing the parameters of the equivalent magnetic circuit, giving the initial magnetic permeability, and calculating the initial magnetic resistance of the stator core; S42, performing magnetic circuit calculation to obtain the magnetic flux Φ at each position; S43, export to the work area to calculate the magnetic flux density B at each position, and obtain a new magnetic permeability through the BH curve of common materials; S44, calculate the relative error between the current magnetic permeability and the magnetic permeability of the last iteration. If the relative error is greater than the given error δ, update the magnetic permeability and continue to iterate until the relative error is less than δ, that is, the calculation result converges. At this time, record the current magnetic flux and magnetic flux density, and the calculation of this network iteration model of the motor is completed.

7. A method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor according to claim 6, characterized in that: The iterative expression of the magnetic permeability is: m k+1 =p1μ k +p2m k-1 (7) In the formula, μ k and μ k-1 are the current magnetic permeability and the magnetic permeability of the previous iteration respectively, p2 and p1 are the current magnetic permeability coefficient and the magnetic permeability coefficient after the previous iteration, p1+p2=1.

8. The method for modeling the magnetic circuit of a dual-stator single-rotor axial permanent magnet motor according to claim 7, characterized in that: The relative error convergence judgment expression is:

9. A double-stator single-rotor axial permanent magnet motor magnetic circuit modeling system, characterized in that: include Parameter definition module: defines the geometric parameters and material parameters of motor components; Magnetic network model building module: divide the nodes of the motor components, represent the magnetic resistance and magnetomotive force of each component according to the geometric parameters and material parameters of the components, and build a magnetic network model; Magnetic circuit model construction module: Based on the magnetic network model, the magnetic flux leakage in the stator slot, the magnetic flux leakage of adjacent permanent magnets through the long pole shoes, and the magnetic flux leakage at the end of the stator winding are considered; the connection method between the motor units is defined; according to the different rotor positions corresponding to different times, the complete magnetic circuit model under different rotor positions is obtained; And, iterative calculation module: based on the complete magnetic circuit model, the magnetic permeability of the stator core is calculated nonlinearly to obtain the final convergence result of the magnetic circuit.

10. A computer storage medium storing a readable program, characterized in that: When the program is run, the modeling method described in any one of claims 1 to 8 can be executed.

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