Calculation method and system for maximizing utilization rate of permanent magnet of built-in n-layer magnetic barrier permanent magnet synchronous motor

Abstract

The invention discloses a calculation method and system for maximizing the utilization rate of a permanent magnet of a built-in n-layer magnetic barrier permanent magnet synchronous motor, belongs to the technical field of permanent magnet synchronous motors, and aims to solve the problem of insufficient utilization rate or excessive consumption of a permanent magnet of a multi-layer magnetic barrier permanent magnet synchronous motor on the premise of ensuring high performance of the motor. The method comprises the following steps: establishing a no-load equivalent magnetic circuit model of the n-layer magnetic barrier permanent magnet synchronous motor; deriving a function relationship between the no-load air gap flux density fundamental wave amplitude and the key structure parameters of the n-layer magnetic barrier permanent magnet synchronous motor; according to the function relation, permanent magnet parameters when the permanent magnet volume is fixed and the fundamental wave amplitude is maximum and permanent magnet parameters when the fundamental wave amplitude is fixed and the permanent magnet volume is minimum are analyzed; the zero-load air gap flux density fundamental wave amplitude of the permanent magnet synchronous motor with the magnetic barrier is obtained through a finite element analysis method, and the effectiveness of the method is verified by comparing a simulation value with a theoretical value. The method is suitable for guiding the design scene of the geometric parameters of the permanent magnet of the built-in n-layer magnetic barrier permanent magnet synchronous motor.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnet synchronous motors, and in particular relates to an analysis method for maximizing the utilization rate of permanent magnets of a built-in n-layer magnetic barrier permanent magnet synchronous motor. Background Art

[0002] In recent years, the automotive industry has shown a rapid development trend. Its vigorous development has not only brought extremely considerable economic benefits, but also had a wide and far-reaching impact in many fields. However, a series of severe environmental and energy problems have also followed. Traditional fuel vehicles will continue to emit a large amount of harmful gases during operation, which will have a serious negative impact on air quality, and thus threaten human health and the balance of the ecosystem. At the same time, the automotive industry's high dependence on fossil energy such as oil has made the energy shortage problem more prominent.

[0003] As the world pays more and more attention to environmental protection and energy efficiency, electric vehicles, as a green and environmentally friendly means of transportation, have gradually come into people's view, showing great potential to compete with and gradually replace traditional internal combustion engine vehicles. Compared with traditional vehicles, electric vehicles can not only significantly reduce greenhouse gas emissions and alleviate energy shortages, but also promote the innovation and application of new energy technologies. As the core component of the electric vehicle drive system, the drive motor plays a vital role in the performance of electric vehicles. Rare earth permanent magnet synchronous motors are widely used in the field of electric vehicles because of their high torque density, high power density and high efficiency, which can effectively reduce energy consumption and extend driving range.

[0004] However, the distribution of rare earth element resources is extremely uneven, with most of the world's rare earth resources concentrated in a few countries and regions. This uneven distribution of resources has led to a complex and fragile supply chain structure for rare earth permanent magnets, and the stability of the supply of rare earth permanent magnets is difficult to effectively guarantee. At the same time, the price of rare earth permanent magnets also fluctuates violently due to a variety of factors. This has greatly increased the uncertainty of electric vehicle costs.

[0005] Therefore, how to optimize the permanent magnet design and maximize its utilization efficiency while ensuring the high performance of the motor has become one of the key strategies to reduce the cost of electric vehicles and achieve sustainable development of the industry. This is not only related to the economic benefits and market competitiveness of electric vehicle companies, but also to the future development direction of the entire electric vehicle industry. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, an object of the present invention is to establish and analyze an open-circuit equivalent magnetic circuit model of an n-layer magnetic barrier permanent magnet synchronous motor according to the principle of magnetic circuit equivalence, and derive the functional relationship between the fundamental wave amplitude of the open-circuit air-gap magnetic density and the structural parameters of the n-layer magnetic barrier permanent magnet synchronous motor.

[0008] The second object of the present invention is to propose a calculation method for maximizing the utilization rate of permanent magnets in an interior-mounted n-layer magnetic barrier permanent magnet synchronous motor, which solves the problem of insufficient or excessive consumption of the utilization rate of permanent magnets in a multi-layer magnetic barrier permanent magnet synchronous motor, that is, it is easier to improve the performance of electric vehicles and control the cost of electric vehicles after maximizing the utilization rate of permanent magnets.

[0009] The third object of the present invention is to propose a calculation system for maximizing the utilization rate of permanent magnets in an interior-mounted n-layer magnetic barrier permanent magnet synchronous motor.

[0010] To achieve the above object, the present invention provides a calculation method for maximizing the utilization rate of permanent magnets in an interior-mounted n-layer magnetic barrier permanent magnet synchronous motor, including the following steps:

[0011] S1: According to the principle of magnetic circuit equivalence, establish an open-circuit equivalent magnetic circuit model of an n-layer magnetic barrier permanent magnet synchronous motor;

[0012] S2: According to the open-circuit equivalent magnetic circuit model, obtain the functional relationship between the fundamental wave amplitude of the open-circuit air-gap magnetic density and the structural parameters of the n-layer magnetic barrier permanent magnet synchronous motor;

[0013] S3: According to the functional relationship, obtain the optimal permanent magnet parameters, and the optimal permanent magnet parameters are: the permanent magnet parameters when the volume of the permanent magnet is certain and the fundamental wave amplitude is the largest, and the permanent magnet parameters when the fundamental wave amplitude is certain and the volume of the permanent magnet is the smallest, thus completing the method.

[0014] Furthermore, a preferred solution is provided: the structural parameters include: the number of pole pairs of the permanent magnet synchronous motor, the width of the permanent magnet, the thickness of the permanent magnet, the mechanical angle of the magnetic barrier of the permanent magnet, the radius of the air gap, the length of the air gap, and the axial length.

[0015] Furthermore, a preferred solution is provided: the S2 includes:

[0016] Perform Fourier decomposition on the periodic open-circuit air-gap magnetic density of the interior-mounted n-layer magnetic barrier permanent magnet synchronous motor to obtain a linear combination of sine and cosine functions;

[0017] Calculate the functional relationship between the Fourier coefficients of the fundamental wave component of the open-circuit air-gap magnetic density and the magnetic density passing through each section of the air gap;

[0018] According to the open-circuit equivalent magnetic circuit model, combined with Kirchhoff's law, obtain the functional relationship between the fundamental wave amplitude of the open-circuit air-gap magnetic density and the structural parameters.

[0019] Furthermore, a preferred solution is provided: The linear combination of the sine and cosine functions is:

[0020]

[0021] where a0 represents the average value within one period, a k , b k are Fourier coefficients, k is the harmonic order, and θ e is the electrical angle. Furthermore, a preferred solution is provided: The calculation method of the electrical angle θ e is as follows:

[0022] θ e = p·θ,

[0023] where p is the number of pole pairs of the permanent magnet synchronous motor; θ is the mechanical angle of the magnetic barrier of the permanent magnet.

[0024] Furthermore, a preferred solution is provided: S3 includes: Based on the Lagrangian idea, when the volume of the permanent magnet is fixed, solve the structural parameters of the permanent magnet that maximize the fundamental wave amplitude of the no-load air-gap magnetic flux density of the n-layer magnetic barrier permanent magnet synchronous motor; when the fundamental wave amplitude of the no-load air-gap magnetic flux density of the n-layer magnetic barrier permanent magnet synchronous motor is fixed, solve the structural parameters of the permanent magnet that minimize the volume of the permanent magnet.

[0025] Furthermore, a preferred solution is provided: The method further includes:

[0026] S4: Use the finite element analysis method to obtain the fundamental wave amplitude of the no-load air-gap magnetic flux density of the single-layer magnetic barrier permanent magnet synchronous motor, and compare the simulation value with the theoretical value to verify the effectiveness of the calculation method for maximizing the utilization rate of the permanent magnet of the built-in n-layer magnetic barrier permanent magnet synchronous motor.

[0027] The present invention also proposes a computer device, which includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the calculation method for maximizing the utilization rate of the permanent magnet of the built-in n-layer magnetic barrier permanent magnet synchronous motor according to any one or more of the above solutions in combination.

[0028] The present invention also proposes a computer-readable storage medium, which is used to store a computer program. The computer program executes the steps of the calculation method for maximizing the utilization rate of the permanent magnet of the built-in n-layer magnetic barrier permanent magnet synchronous motor according to any one or more of the above solutions in combination.

[0029] The calculation system for maximizing the utilization rate of permanent magnets in the built-in n-layer magnetic barrier permanent magnet synchronous motor proposed by the present invention is implemented based on the calculation method for maximizing the utilization rate of permanent magnets in the built-in n-layer magnetic barrier permanent magnet synchronous motor described in any one or a combination of the above-mentioned solutions. The system includes:

[0030] Model establishment module: used to establish an equivalent magnetic circuit model of no-load for the n-layer magnetic barrier permanent magnet synchronous motor according to the principle of equivalent magnetic circuit;

[0031] Function determination module: used to obtain the functional relationship between the fundamental wave amplitude of the no-load air-gap magnetic flux density and the structural parameters of the n-layer magnetic barrier permanent magnet synchronous motor according to the no-load equivalent magnetic circuit model;

[0032] Parameter calculation module: used to obtain the optimal permanent magnet parameters according to the functional relationship. The optimal permanent magnet parameters are: the permanent magnet parameters when the fundamental wave amplitude is the largest with a certain permanent magnet volume, and the permanent magnet parameters when the permanent magnet volume is the smallest with a certain fundamental wave amplitude.

[0033] Compared with the prior art, the advantages of the present invention are as follows:

[0034] The prior art faces the problems of unstable supply and large price fluctuations of rare earth permanent magnets, resulting in increased cost uncertainty for electric vehicles. The method proposed by the present invention can, by establishing an equivalent magnetic circuit model of no-load for the n-layer magnetic barrier permanent magnet synchronous motor and analyzing the functional relationship between the fundamental wave amplitude of the no-load air-gap magnetic flux density and the key structural parameters, find the permanent magnet parameters that maximize the fundamental wave amplitude when the permanent magnet volume is certain, and find the permanent magnet parameters that minimize the permanent magnet volume when the fundamental wave amplitude is certain. It effectively solves the problems of insufficient utilization rate or excessive consumption of permanent magnets in the multi-layer magnetic barrier permanent magnet synchronous motor, significantly improves the utilization efficiency of permanent magnets, and helps to reduce the cost of electric vehicles.

[0035] The functional relationship derived by the method proposed by the present invention provides convenience for selecting the key structural parameters of permanent magnets when maximizing the utilization rate of permanent magnets in this type of motor, reduces the design difficulty, and makes the motor design process more scientific and efficient.

[0036] The method proposed by the present invention adopts the finite element analysis method to compare the simulation value and the theoretical value of the fundamental wave amplitude of the no-load air-gap magnetic flux density of the single-layer magnetic barrier permanent magnet synchronous motor. The results show that: when the permanent magnet volume is certain, the error between the optimal magnetic barrier angle obtained by finite element simulation analysis and the result obtained by the equivalent magnetic circuit method is 3.53%; when the fundamental wave amplitude of the no-load air-gap magnetic flux density is certain, the error between the optimal magnetic barrier angle obtained by finite element simulation analysis and the result obtained by the equivalent magnetic circuit method is 6.87%. This fully shows that the method has high accuracy and provides a reliable theoretical basis and calculation method for motor design.

[0037] The calculation method proposed by the present invention has strong applicability and can be extended and applied to the permanent magnet design of an n-layer magnetic barrier permanent magnet synchronous motor, providing a unified design idea and method for the design of permanent magnet synchronous motors with different numbers of magnetic barrier layers and expanding its application scope.

[0038] In summary, the calculation method and system for maximizing the utilization rate of permanent magnets in an interior permanent magnet synchronous motor with n-layer magnetic barriers proposed by the present invention have significant advantages in optimizing the permanent magnet design, reducing the design difficulty, improving the calculation accuracy, and guiding the motor design, etc., and are of great significance for promoting the development of permanent magnet synchronous motor technology and reducing the cost of electric vehicles.

[0039] The present invention is applicable to the design scenario of guiding the geometric parameters of permanent magnets in an interior permanent magnet synchronous motor with n-layer magnetic barriers. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Figure 1 It is a flowchart of the calculation method for maximizing the utilization rate of permanent magnets in an interior permanent magnet synchronous motor with n-layer magnetic barriers according to the first specific embodiment of the present invention;

[0042] Figure 2 It is a structural diagram of an interior permanent magnet synchronous motor with n-layer magnetic barriers according to the first specific embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of the simplified magnetic circuit model of an interior permanent magnet synchronous motor with n-layer magnetic barriers under a half pole according to the first specific embodiment of the present invention;

[0044] Figure 4 It is an equivalent magnetic circuit diagram of the simplified magnetic circuit model of an interior permanent magnet synchronous motor with n-layer magnetic barriers under a half pole according to the first specific embodiment of the present invention;

[0045] Figure 5 It is a schematic diagram of the magnetic barrier mechanical angle structure parameters of an n-layer magnetic barrier permanent magnet synchronous motor according to the first specific embodiment of the present invention;

[0046] Figure 6 It is a schematic diagram of the permanent magnet size structure parameters of an n-layer magnetic barrier permanent magnet synchronous motor according to the first specific embodiment of the present invention;

[0047] Figure 7 It is a schematic diagram of the theoretical waveform of the no-load air-gap magnetic density of an n-layer magnetic barrier permanent magnet synchronous motor according to the first specific embodiment of the present invention;

[0048] Figure 8 Structural diagram of the built-in one-layer magnetic barrier permanent magnet synchronous motor described in the second specific embodiment of the present invention;

[0049] Figure 9 Comparison diagram of the fundamental wave amplitude of the no-load air-gap magnetic flux density between the finite element method and the magnetic circuit method when the volume of the permanent magnet is constant in the second specific embodiment of the present invention;

[0050] Figure 10 Comparison diagram of the fundamental wave amplitude of the no-load air-gap magnetic flux density between the finite element method and the magnetic circuit method when the fundamental wave amplitude is constant in the second specific embodiment of the present invention;

[0051] In the figure, 1 is the stator core, 2 is the armature winding, 3 is the air gap, 4 is the magnetic barrier, 5 is the permanent magnet 1, 6 is the permanent magnet 2, 7 is the permanent magnet n-1, 8 is the permanent magnet n, 9 is the rotor core, and 10 is the shaft. Specific embodiments

[0052] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0053] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0054] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification of the present application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0056] In the following description, many specific details are set forth to provide a thorough understanding of the present application. However, the present application may be practiced in other ways different from those described herein. Persons skilled in the art can make similar extensions without departing from the spirit of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0057] Embodiment 1:

[0058] Refer to Figures 1 to 7 to describe this embodiment.

[0059] This embodiment proposes a calculation method for maximizing the utilization rate of permanent magnets in an embedded n-layer magnetic barrier permanent magnet synchronous motor, as Figure 1 shown. The method includes:

[0060] S1: According to the principle of magnetic circuit equivalence, establish an open-circuit equivalent magnetic circuit model of the n-layer magnetic barrier permanent magnet synchronous motor;

[0061] S2: According to the open-circuit equivalent magnetic circuit model, obtain the functional relationship between the fundamental wave amplitude of the open-circuit air-gap magnetic flux density and the structural parameters of the n-layer magnetic barrier permanent magnet synchronous motor;

[0062] S3: According to the functional relationship, obtain the optimal permanent magnet parameters. The optimal permanent magnet parameters are: the permanent magnet parameters when the volume of the permanent magnet is fixed and the fundamental wave amplitude is the largest, and the permanent magnet parameters when the fundamental wave amplitude is fixed and the volume of the permanent magnet is the smallest, thus completing the method.

[0063] Specifically:

[0064] In step S1, according to the principle of magnetic circuit equivalence, establish an open-circuit equivalent magnetic circuit model of the n-layer magnetic barrier permanent magnet synchronous motor.

[0065] The structural diagram of the embedded n-layer magnetic barrier permanent magnet synchronous motor is as Figure 2 shown. Since the magnetic permeability of silicon steel sheets is relatively large, the magnetic resistance of the stator and rotor cores can be ignored; generally, due to the action of the (i + 1)-th layer of permanent magnets, the magnetic flux passing through the i-th magnetic barrier is small, so the magnetic resistance of the magnetic barrier can also be ignored in the analysis; the magnetic bridge is usually designed to be narrow to reduce magnetic leakage, so the influence of the magnetic bridge is limited and can be ignored. Due to the symmetry of the magnetic circuit, in this embodiment, only an open-circuit equivalent magnetic circuit model of half a pole of the n-layer magnetic barrier permanent magnet synchronous motor needs to be established, as Figure 3 and Figure 4 shown. In Figure 4 , F PMi and R PMi are respectively the equivalent magnetomotive force and equivalent magnetic resistance of the i-th magnetic pole; R gi is the equivalent magnetic resistance of the i-th section of the air gap, which can be expressed as:

[0066]

[0067] Wherein, μ0 is the magnetic permeability of vacuum; B ri and μ ri are respectively the remanence and magnetic permeability of the magnetic pole i; R is the air-gap radius; L is the axial length; δ is the air-gap length; θ i is the mechanical magnetic-barrier angle of the magnetic pole i, as shown in Figure 5 ; b PMi and h PMi are respectively the width and thickness of the magnetic pole i under half pole, as shown in Figure 6 .

[0068] In the step S2, according to the no-load equivalent magnetic circuit model, the functional relationship between the fundamental amplitude of the no-load air-gap magnetic density and the key structural parameters of the n-layer magnetic-barrier permanent magnet synchronous motor is obtained;

[0069] Specifically, Figure 7 is the theoretical waveform of the no-load air-gap magnetic density of the built-in n-layer magnetic-barrier permanent magnet synchronous motor. By performing Fourier decomposition on it, the periodic magnetic density B is decomposed into a linear combination of sine and cosine functions:

[0070]

[0071] where a0 represents the average value within one period, a k , b k are Fourier coefficients, k is the harmonic order, and θ e is the electrical angle.

[0072] θ e = p·θ(5)

[0073] p is the number of pole pairs of the permanent magnet synchronous motor; θ is the magnetic-barrier mechanical angle of the permanent magnet.

[0074] In this embodiment, an 8-pole 48-slot permanent magnet synchronous motor is studied, so the number of pole pairs p is taken as 4.

[0075] It can be obtained from theoretical analysis that the no-load air-gap magnetic density waveform of the n-layer magnetic-barrier permanent magnet synchronous motor is an even function, and b k is always 0.

[0076] The Fourier coefficient a1 of the fundamental wave component is obtained according to the following formula:

[0077]

[0078] In the above formula, θ i is the magnetic-barrier mechanical angle of the magnetic pole i, and h i is the magnitude of the magnetic density passing through the i-th section of the air gap, which is obtained according to the following formula:

[0079]

[0080] In the formula, R is the air-gap radius; L is the axial length.

[0081] According to the magnetic circuit model, F PMi and R PMi are the equivalent magnetomotive force and equivalent magnetic resistance of magnetic pole i respectively; R gi is the equivalent magnetic resistance of the i-th air gap; Φi is the magnetic flux in the i-th grid area, i indicates the specific position of the magnetic circuit area; Φ gi is the magnetic flux passing through the i-th air gap. According to Kirchhoff's law, there is a relationship:

[0082]

[0083]

[0084] In S3, according to the functional relationship, the optimal permanent magnet parameters are obtained, and the optimal permanent magnet parameters are: the permanent magnet parameters when the permanent magnet volume is constant and the fundamental wave amplitude is maximum, and the permanent magnet parameters when the fundamental wave amplitude is constant and the permanent magnet volume is minimum, thereby completing the method.

[0085] Specifically, based on the Lagrangian idea, when the volume of the permanent magnet is constant, the permanent magnet structural parameters that make the no-load air gap magnetic flux fundamental wave amplitude of the n-layer magnetic barrier permanent magnet synchronous motor reach the maximum value are solved; when the no-load air gap magnetic flux fundamental wave amplitude of the n-layer magnetic barrier permanent magnet synchronous motor is constant, the permanent magnet structural parameters that minimize the volume of the permanent magnet are solved.

[0086] When the volume of the permanent magnet is constant, since the axial length L of the motor is a constant, the volume restriction of the permanent magnet can be converted into a constraint on the two-dimensional cross-sectional area of the permanent magnet. By applying the Lagrange multiplier method, the following formula can be obtained:

[0087]

[0088] Where λ is the Lagrange multiplier and S0 is the given two-dimensional cross-sectional area of the permanent magnet.

[0089] The solution of the simultaneous equations obtained through the Lagrange multiplier method is the optimal solution of the objective function under the constraints, that is, the optimal solution of the permanent magnet structural parameters when the no-load air gap magnetic flux fundamental wave amplitude of the n-layer magnetic barrier permanent magnet synchronous motor reaches the maximum when the two-dimensional cross-sectional area of the permanent magnet is given.

[0090] When the no-load air gap magnetic flux fundamental wave amplitude a1 of the n-layer magnetic barrier permanent magnet synchronous motor is constant, since the motor axial length L is a constant, the problem of minimizing the volume of the permanent magnet can be transformed into the problem of minimizing the two-dimensional cross-sectional area of the permanent magnet. By applying the Lagrange multiplier method, the following formula can be obtained:

[0091]

[0092] In the formula, λ is the Lagrange multiplier, and a0 is the fundamental wave amplitude of the no-load air-gap magnetic density of the given n-layer magnetic barrier permanent magnet synchronous motor.

[0093] Through the Lagrange multiplier method, the solution obtained by simultaneously solving the equations is the optimal solution of the objective function under the constraint conditions, that is, when the fundamental wave amplitude of the no-load air-gap magnetic density of the n-layer magnetic barrier permanent magnet synchronous motor is given, the optimal solution of the permanent magnet structure parameters when the two-dimensional cross-sectional area of the permanent magnet reaches the minimum.

[0094] The method described in this embodiment further includes S4: obtaining the fundamental wave amplitude of the no-load air-gap magnetic density of the single-layer magnetic barrier permanent magnet synchronous motor by using the finite element analysis method, and comparing the simulation value with the theoretical value to verify the effectiveness of the calculation method for maximizing the permanent magnet utilization rate of the built-in n-layer magnetic barrier permanent magnet synchronous motor.

[0095] The calculation method for maximizing the permanent magnet utilization rate of the built-in n-layer magnetic barrier permanent magnet synchronous motor described in this embodiment can deduce the functional relationship between the fundamental wave amplitude of the no-load air-gap magnetic density of the n-layer magnetic barrier permanent magnet synchronous motor and the key structure parameters, reduces the design difficulty of selecting the key structure parameters of the permanent magnet when maximizing the permanent magnet utilization rate of this type of motor, and can be extended to the permanent magnet design of the n-layer magnetic barrier permanent magnet synchronous motor.

[0096] Embodiment 2:

[0097] Refer to Figures 8 to 10 to illustrate this embodiment.

[0098] This embodiment is a further example to illustrate the calculation method for maximizing the permanent magnet utilization rate of the built-in n-layer magnetic barrier permanent magnet synchronous motor described in Embodiment 1.

[0099] Specifically, to verify the accuracy of the design scheme, the specific structure parameters of the single-layer magnetic barrier permanent magnet synchronous motor are shown in the following table, where R stator1 is the outer diameter of the stator, R stator2 is the inner diameter of the stator, R is the outer diameter of the rotor, and R rotor2 is the inner diameter of the rotor.

[0100] Table 1 Structure parameters of the single-layer magnetic barrier permanent magnet synchronous motor

[0101] Parameter Value Unit <![CDATA[R stator1 > 145 mm <![CDATA[R stator2 > 86.8 mm R 86 mm <![CDATA[R rotor2 > 45 mm δ 0.8 mm <![CDATA[h PM1 > 6.6 mm

[0102] The structure diagram of the single-layer magnetic barrier permanent magnet synchronous motor is as Figure 8 shown.

[0103] Due to the symmetry of the magnetic circuit, only the no-load magnetic circuit model of the single-layer magnetic barrier permanent magnet synchronous motor under half a pole is established in this embodiment.

[0104] F PM1 and R PM1They are the equivalent magnetomotive force and equivalent magnetic resistance of magnetic pole 1 respectively; R g1 is the equivalent magnetic resistance of the first air gap section, which can be expressed as:

[0105]

[0106] In the formula: μ0 is the magnetic permeability of vacuum; B r1 and μ r1 are the remanence and magnetic permeability of magnetic pole 1 respectively; R is the radius of the air gap; L is the axial length; δ is the air gap length; θ1 is the mechanical magnetic barrier angle of magnetic pole 1; b PM1 and h PM1 are the width and thickness of magnetic pole 1 under half pole respectively.

[0107] According to formula (6) - formula (9) and formula (16), the functional relationship between the no-load air-gap magnetic density, the fundamental wave amplitude of the no-load air-gap magnetic density and the key structural parameters of the permanent magnet can be obtained as:

[0108]

[0109] When the volume of the permanent magnet is constant, since the axial length L of the motor is a constant, the volume limitation of the permanent magnet can be transformed into a constraint on the two-dimensional cross-sectional area of the permanent magnet. By the Lagrange multiplier method, the following formula can be obtained:

[0110]

[0111] In the formula, λ is the Lagrange multiplier and S0 is the given two-dimensional cross-sectional area of the permanent magnet. When the given area S0 = 65 mm 2 , substituting into formula (19) and (20), when the fundamental wave amplitude of the no-load air-gap magnetic density reaches the maximum, the key parameters of the permanent magnet can be jointly solved as b PM1 = 9.8485 mm, θ1 = 8.4816°. Change the mechanical angle of the magnetic barrier every 0.5° within 3.9816° - 12.9816° to obtain the corresponding motor structure and conduct simulations. The fundamental wave amplitude of the no-load air-gap magnetic density corresponding to the magnetic barrier angle obtained by the equivalent magnetic circuit method and the finite element simulation method is as shown Figure 9 in the large figure. To further analyze the key area, conduct high-precision simulations at intervals of 0.1° within the range of 8.2816° to 9.0816°, and the results are as shown Figure 9 in the small figure.

[0112] The simulation results show that the optimal magnetic barrier angle obtained by the finite element method is 8.7816°. Compared with the theoretical value of 8.4816° of the equivalent magnetic circuit method, the error is 3.53%. This indicates that the proposed scheme has high accuracy.

[0113] When the amplitude a1 of the fundamental wave of the no-load air-gap magnetic density is constant, since the axial length L of the motor is a constant, the problem of minimizing the volume of the permanent magnet can be transformed into the problem of minimizing the two-dimensional cross-sectional area of the permanent magnet. By the Lagrange multiplier method, the following formula can be obtained:

[0114]

[0115] In the formula, λ is the Lagrange multiplier, and a0 is the amplitude of the fundamental wave of the no-load air-gap magnetic density of a given one-layer magnetic-barrier permanent magnet synchronous motor. When the given amplitude a0 of the fundamental wave of the no-load air-gap magnetic density is 0.6 T, substituting into formulas (21) and (22), the key parameters of the permanent magnet can be jointly solved when the volume of the permanent magnet is minimized, and the key parameter of the permanent magnet is b PM1 = 11.166 mm, θ1 == 8.7333°. The mechanical angle of the magnetic barrier is changed every 0.5° within 4.2333° - 13.2333°, and the corresponding motor structures are obtained for simulation. The amplitude of the fundamental wave of the no-load air-gap magnetic density corresponding to the magnetic barrier angle obtained by the equivalent magnetic circuit method and the finite element simulation method is as Figure 10 shown in the large figure in the middle. To further analyze the key area, high-precision simulation is carried out at intervals of 0.1° within the range of 8.5333° to 9.6333°, and the results are as Figure 10 shown in the small figure in the middle.

[0116] The simulation results show that the optimal magnetic barrier angle obtained by the finite element method is 9.3333°. Compared with the theoretical value of 8.7333° of the equivalent magnetic circuit method, the error is 6.87%. This shows that the proposed scheme has high accuracy.

[0117] Embodiment 3:

[0118] This embodiment proposes a calculation system for maximizing the utilization rate of permanent magnets of an embedded n-layer magnetic-barrier permanent magnet synchronous motor. The system is implemented based on the calculation method for maximizing the utilization rate of permanent magnets of the embedded n-layer magnetic-barrier permanent magnet synchronous motor as described in Embodiment 1. The system includes:

[0119] Model establishment module: used to establish an equivalent no-load magnetic circuit model of an n-layer magnetic-barrier permanent magnet synchronous motor according to the principle of magnetic circuit equivalence;

[0120] Function determination module: used to obtain the functional relationship between the amplitude of the fundamental wave of the no-load air-gap magnetic density and the structural parameters of an n-layer magnetic-barrier permanent magnet synchronous motor according to the equivalent no-load magnetic circuit model;

[0121] Parameter calculation module: used to obtain the optimal permanent magnet parameters according to the functional relationship. The optimal permanent magnet parameters are: the permanent magnet parameters when the volume of the permanent magnet is constant and the amplitude of the fundamental wave is the largest, and the permanent magnet parameters when the amplitude of the fundamental wave is constant and the volume of the permanent magnet is the smallest.

[0122] Those skilled in the art can understand that the above description is only the preferred embodiment of the present invention. The features described in each embodiment and / or claim of the present disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly recorded in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0123] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0124] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

[0125] Those skilled in the art should understand that the embodiments of the present disclosure can be provided as a method, a system, or a computer program product. Therefore, the present disclosure can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0126] The present disclosure is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate for realizing in the process Figure 1 one process or multiple processes and / or blocks Figure 1Apparatus for functions specified in one or more boxes. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction apparatus that implements the process Figure 1 one or more processes and / or boxes Figure 1 functions specified in one or more boxes.

[0127] These computer program instructions may also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are performed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more processes and / or boxes Figure 1 one or more boxes.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure rather than to limit the scope of its protection. Although the present disclosure has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: after reading the present disclosure, those skilled in the art may still make various changes, modifications or equivalent replacements to the specific embodiments of the invention, but these changes, modifications or equivalent replacements are all within the scope of protection of the claims pending for publication.

Claims

1. Calculation method for maximizing the utilization rate of permanent magnets in an internal n-layer magnetic barrier permanent magnet synchronous motor, characterized in that, The method includes: S1: Establish an open - circuit equivalent magnetic circuit model of an n - layer magnetic barrier permanent - magnet synchronous motor according to the magnetic circuit equivalent principle; S2: Obtain the functional relationship between the fundamental wave amplitude of the open - circuit air - gap magnetic density and the structural parameters of the n - layer magnetic barrier permanent - magnet synchronous motor according to the open - circuit equivalent magnetic circuit model; S3: Obtain the optimal permanent - magnet parameters according to the functional relationship. The optimal permanent - magnet parameters are: the permanent - magnet parameters when the permanent - magnet volume is fixed and the fundamental wave amplitude is the largest, and the permanent - magnet parameters when the fundamental wave amplitude is fixed and the permanent - magnet volume is the smallest, thus completing the method.

2. The calculation method for maximizing the utilization rate of permanent magnets in the built-in n-layer magnetic barrier permanent magnet synchronous motor according to claim 1, characterized in that The structural parameters include: the number of pole pairs of the permanent - magnet synchronous motor, the width of the permanent magnet, the thickness of the permanent magnet, the mechanical angle of the magnetic barrier of the permanent magnet, the air - gap radius, the air - gap length, and the axial length.

3. The calculation method for maximizing the utilization rate of permanent magnets in the built-in n-layer magnetic barrier permanent magnet synchronous motor according to claim 1, wherein, S2 includes: Perform Fourier decomposition on the periodic open - circuit air - gap magnetic density of the interior - type n - layer magnetic barrier permanent - magnet synchronous motor to obtain a linear combination of sine and cosine functions; Calculate the functional relationship between the Fourier coefficients of the fundamental wave component of the open - circuit air - gap magnetic density and the magnetic density passing through each air - gap segment; According to the open - circuit equivalent magnetic circuit model and in combination with Kirchhoff's law, obtain the functional relationship between the fundamental wave amplitude of the open - circuit air - gap magnetic density and the structural parameters.

4. The calculation method for maximizing the utilization rate of permanent magnets of the built-in n-layer magnetic barrier permanent magnet synchronous motor according to claim 3, characterized in that The linear combination of the sine and cosine functions is: Among them, a0 represents the average value within a period, a k , b k is the Fourier coefficient, k is the harmonic order, θ e The electrical angle.

5. The calculation method for maximizing the utilization rate of permanent magnets in the built-in n-layer magnetic barrier permanent magnet synchronous motor according to claim 3, characterized in that, The electrical angle θ e is calculated as follows: θ e = p·θ, p is the number of pole pairs of the permanent - magnet synchronous motor; θ is the mechanical angle of the magnetic barrier of the permanent magnet.

6. The calculation method for maximizing the utilization rate of permanent magnets in the built-in n-layer magnetic barrier permanent magnet synchronous motor according to claim 1, wherein S3 includes: Based on the Lagrangian idea, when the permanent - magnet volume is fixed, solve for the permanent - magnet structural parameters that maximize the fundamental wave amplitude of the open - circuit air - gap magnetic density of the n - layer magnetic barrier permanent - magnet synchronous motor; when the fundamental wave amplitude of the open - circuit air - gap magnetic density of the n - layer magnetic barrier permanent - magnet synchronous motor is fixed, solve for the permanent - magnet structural parameters that minimize the permanent - magnet volume.

7. The calculation method for maximizing the utilization rate of permanent magnets in the built-in n-layer magnetic barrier permanent magnet synchronous motor according to claim 1, characterized in that, The method further includes: S4: Use the finite - element analysis method to obtain the fundamental wave amplitude of the open - circuit air - gap magnetic density of a single - layer magnetic barrier permanent - magnet synchronous motor, and compare the simulation value with the theoretical value to verify the effectiveness of the calculation method for maximizing the utilization rate of permanent magnets in the interior - type n - layer magnetic barrier permanent - magnet synchronous motor.

8. A computer device, characterized in that, It includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the calculation method for maximizing the utilization rate of permanent magnets in the interior - type n - layer magnetic barrier permanent - magnet synchronous motor according to any one of claims 1 - 7.

9. A computer-readable storage medium, characterized in that, The computer - readable storage medium is used to store a computer program, and the computer program executes the steps of the calculation method for maximizing the utilization rate of permanent magnets in the interior - type n - layer magnetic barrier permanent - magnet synchronous motor according to any one of claims 1 - 7.

10. A calculation system for maximizing the utilization rate of permanent magnets in an embedded n-layer magnetic barrier permanent magnet synchronous motor, characterized in that, The system is implemented based on the calculation method for maximizing the utilization rate of permanent magnets in the interior - type n - layer magnetic barrier permanent - magnet synchronous motor according to any one of claims 1 - 7. The system includes: A model - establishment module: used to establish an open - circuit equivalent magnetic circuit model of an n - layer magnetic barrier permanent - magnet synchronous motor according to the magnetic circuit equivalent principle; A function - determination module: used to obtain the functional relationship between the fundamental wave amplitude of the open - circuit air - gap magnetic density and the structural parameters of the n - layer magnetic barrier permanent - magnet synchronous motor according to the open - circuit equivalent magnetic circuit model; Parameter calculation module: used to obtain the optimal permanent magnet parameters according to the functional relationship, where the optimal permanent magnet parameters are: the permanent magnet parameters when the volume of the permanent magnet is fixed and the fundamental wave amplitude is the largest, and the permanent magnet parameters when the fundamental wave amplitude is fixed and the volume of the permanent magnet is the smallest.

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