A method for calculating the flux linkage of a magnetic field modulation permanent magnet motor

Abstract

The present invention discloses a method for calculating the flux linkage of a magnetic field modulated permanent magnet motor based on the air gap filtering effect and the stator slotting effect. By comparing the influence of different air gap flux density value positions on the flux linkage calculation, the air gap filtering effect of the magnetic field modulated permanent magnet motor is revealed: compared with the traditional air gap flux density value taken at the center of the physical air gap, the air gap flux density value taken at the inner diameter of the stator core of the present invention is closer to the actual flux density component that enters the stator core and interlinks with the winding. The present invention also reveals the slotting effect of the magnetic field modulated motor: the stator slot opening will cause the winding function of the stator armature to change, so that the no-load flux density entering the slot cannot fully interlink with all the conductor coils in the slot, thereby affecting the accuracy of the flux linkage calculation; the present invention improves the original flux linkage model by considering the air gap filtering effect and the stator slotting effect of the magnetic field modulated motor, greatly reducing the calculation error and improving the accuracy of the flux linkage calculation model of the magnetic field modulated permanent magnet motor.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic field modulation permanent magnet motors, and in particular relates to a magnetic field modulation permanent magnet motor flux calculation method based on air gap filtering effect and stator slotting effect. Background Art

[0002] Compared with traditional permanent magnet motors, magnetic field modulation permanent magnet motors can greatly improve their torque density due to the magnetic field modulation effect, and have good application prospects in electric vehicles, robots and other fields. Magnetic field modulation permanent magnet motors mainly include switched flux permanent magnet motors, flux reversal permanent magnet motors, vernier permanent magnet motors, magnetic gear permanent magnet motors, etc. These new motors enrich the connotation of motor disciplines on the one hand, and bring new challenges to motor theory on the other.

[0003] The study of the air gap magnetic field and working principle of the magnetic field modulation permanent magnet motor is the basis for the research and optimization of its topological structure. Through the analysis of its magnetic field modulation effect, it is found that the magnetic field modulation permanent magnet motor has multiple working harmonics. Establishing a quantitative analysis method for the contribution of each order magnetic flux harmonic to the magnetic flux linkage is the basis for the study of the working principle of the magnetic field modulation permanent magnet motor.

[0004] Reference [Chen Canruo. Research on Topology of High Torque Density Stator Permanent Magnet Field Modulation Motor [D]. Huazhong University of Science and Technology, 2022. DOI: 10.27157 / d.cnki.ghzku.2022.000546] By comparing the theoretical calculation results of the flux linkage of a flux reversal permanent magnet motor with the finite element simulation results, it was found that the calculation error was as high as 7.7%, which affected the quantitative analysis accuracy of the contribution of magnetic flux harmonics to the motor flux linkage, and brought difficulties to further analysis of the working principle of the motor. There are not many studies on the causes of the calculation error of the flux linkage of the flux reversal permanent magnet motor. The above-mentioned literature believes that it may be due to the permanent magnets attached to the surface of the stator teeth of the flux reversal permanent magnet motor, resulting in the air gap position being far away from the tooth slot where the armature winding is located, and there is a difference between the actual magnetic flux component linked with the winding and the air gap magnetic flux component. In addition, the research on other magnetic field modulation motors can also be used as a reference. For example, the literature [ZHU J, ZUO Y, CHEN H, et al. Deep-Investigated Analytical Modeling of aSurface Permanent Magnet Vernier Motor[J / OL]. IEEE Transactions on Industrial Electronics, 2022, 69(12): 12336-12347. DOI:10.1109 / TIE.2021.3134075] points out that a larger stator slot opening of a vernier motor will also affect the process of generating magnetic flux, and this problem may also exist in a flux reversal permanent magnet motor with a larger slot opening. The literature [Huang Hailin. Theoretical analysis and topological research of multi-working magnetomotive force magnetic field modulation motor [D]. Huazhong University of Science and Technology, 2021. DOI: 10.27157 / d.cnki.ghzku.2021.006562] believes that the tangential air gap flux density of the flux reversal permanent magnet motor is large, while the traditional flux method ignores the tangential air gap flux density. Considering the tangential air gap flux density of the motor, it is proposed to calculate the average torque of the motor according to the Maxwell tensor method to reduce the torque calculation error; however, the calculation of the torque of the flux reversal permanent magnet motor according to the Maxwell tensor method bypasses the motor flux calculation process. This method cannot solve the problem of large flux calculation error of the flux reversal motor. Summary of the invention

[0005] In view of the above, the present invention provides a method for calculating the flux linkage of a magnetic field modulated permanent magnet motor based on the air gap filtering effect and the stator slotting effect. By changing the magnetic flux value taking position (traditionally, the magnetic flux value is extracted at the center of the physical air gap of the motor, while the present invention extracts the magnetic flux value at the inner diameter of the stator core) and considering the stator slot coefficient, the error between the no-load magnetic flux calculation result and the finite element simulation result is reduced.

[0006] A method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slot effect comprises the following steps:

[0007] (1) Considering the air gap filtering effect of the magnetic field modulated permanent magnet motor, the magnetic flux harmonic component at the inner diameter of the stator core is selected to calculate the flux linkage, and its effect is verified;

[0008] (2) Considering the stator slot effect of the magnetic field modulation permanent magnet motor, the magnetic flux is calculated by adding the stator slot coefficient, and its effect is verified;

[0009] (3) Taking into account the air gap filtering effect and stator slot effect of the magnetic field modulation permanent magnet motor, the magnetic flux density value location is changed to the inner diameter of the stator core, and the stator slot coefficient is introduced. An improved flux calculation model is established and used to calculate the fundamental amplitude of the flux of the magnetic field modulation permanent magnet motor.

[0010] Furthermore, the specific implementation method of step (1) is as follows: first, by finite element simulation, the magnetic flux waveforms taken from the center of the motor's physical air gap and the inner diameter of the stator core are obtained, and the spectrum analysis of the magnetic flux waveform is performed to obtain the amplitudes of each order of no-load magnetic flux at different positions; then, the magnetic flux value extracted from the center of the motor's physical air gap is used to calculate the magnetic flux fundamental wave amplitude, and at the same time, the magnetic flux value extracted from the inner diameter of the motor's stator core is used to calculate the magnetic flux fundamental wave amplitude; the above two magnetic flux fundamental wave amplitude calculation results are compared with the finite element simulation results, revealing the existence of an air gap filtering effect in the magnetic field modulated permanent magnet motor, and verifying that the magnetic flux calculation error can be reduced by selecting the magnetic flux harmonic component at the inner diameter of the stator core, thereby reducing the influence of the air gap filtering effect on the magnetic flux calculation.

[0011] Furthermore, it can be seen through verification in step (1) that the air gap of the magnetic field modulation permanent magnet motor and the spatial structure of the permanent magnet have a filtering effect on the air gap magnetic flux at the center of the motor's physical air gap, so that the magnetic flux harmonic component that actually enters the stator core and interlinks with the winding is different from the magnetic flux harmonic component at the center of the physical air gap, and the magnetic flux harmonic component close to the inner diameter of the stator core is closer to the magnetic flux harmonic component that actually enters the stator core and interlinks with the winding.

[0012] Furthermore, the expression for calculating the fundamental amplitude of the flux linkage using the magnetic flux value extracted at the center of the motor's physical air gap is as follows:

[0013]

[0014] in: ψ p It represents the fundamental amplitude of flux linkage of magnetic field modulated permanent magnet motor. r g is the motor physical air gap radius, l sk is the axial length of the motor,N s is the number of series turns of each phase armature winding, k n For the n The winding coefficient of the order, B n The center of the motor's physical air gap n The harmonic amplitude of magnetic density of order; if and only if | iP m ± P r |= J At that time, n The magnetic flux corresponding to the order harmonic is not zero, that is, the order harmonic is the working harmonic. n is the harmonic order under certain conditions and n =| iP m ± P r |= J , P is the number of armature winding pole pairs, P m is the number of permanent magnet pole pairs, P r is the number of motor rotor teeth, i represents the order of magnetic density harmonics, j is the order of the stator slot coefficient.

[0015] Furthermore, the expression for calculating the fundamental amplitude of the flux linkage using the magnetic flux value extracted from the inner diameter of the motor stator core is as follows:

[0016]

[0017] in: D s is the inner diameter of the stator core, B sn The inner diameter of the stator core n The harmonic amplitude of magnetic density of order.

[0018] Furthermore, the specific implementation method of step (2) is as follows: since the stator slotting will cause the winding function of the stator armature to change, the no-load magnetic flux entering the slot cannot fully interlink with all the conductor coils in the slot; the stator slotting coefficient is defined according to the amplitude of each order harmonic component of the winding function, the magnetic flux amplitude generated by the harmonic components of each order of magnetic flux after considering the influence of the stator slotting needs to be multiplied by the stator slotting coefficient of the corresponding order, and the magnetic flux amplitude generated by the harmonic components of each order of magnetic flux after correction is added to obtain the calculation result of the magnetic flux fundamental wave amplitude after considering the stator slotting coefficient; the calculation result of the magnetic flux fundamental wave amplitude before and after the introduction of the stator slotting coefficient is compared with the finite element simulation result, revealing the existence of the stator slotting effect in the magnetic field modulation permanent magnet motor, and verifying that the addition of the stator slotting coefficient can reduce the magnetic flux calculation error and reduce the influence of the stator slotting effect on the magnetic flux calculation.

[0019] Furthermore, the expression of the stator slot coefficient is as follows:

[0020]

[0021] in: k nα Indicates n The stator slot coefficient of the order, α represents the stator slot opening angle, n is the harmonic order under certain conditions and n =| iP m ± P r |= J .

[0022] Furthermore, the improved magnetic flux calculation model in step (3) is expressed as follows:

[0023]

[0024] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor is used to execute the computer program to implement the above-mentioned magnetic flux calculation method of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect.

[0025] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned magnetic flux calculation method for a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect.

[0026] In view of the problem of large errors in the flux calculation model of the traditional magnetic field modulation permanent magnet motor, the present invention reveals the air gap filtering effect of the magnetic field modulation permanent magnet motor by comparing the influence of different air gap flux value positions on the flux calculation: compared with the traditional air gap flux value taken at the center of the physical air gap, the air gap flux value taken at the inner diameter of the stator core is closer to the actual flux component entering the stator core and interlinking with the winding. At the same time, the present invention also reveals the slotting effect of the magnetic field modulation motor: the stator slot opening will cause the winding function of the stator armature to change, so that the no-load flux entering the slot cannot fully interlink with all the conductor coils in the slot, thereby affecting the accuracy of the flux calculation; the present invention improves the original flux model by considering the air gap filtering effect and stator slotting effect of the magnetic field modulation motor, greatly reducing the calculation error and improving the accuracy of the flux calculation model of the magnetic field modulation permanent magnet motor.

[0027] Comparing the traditional calculation results of the fundamental wave amplitude of the flux, the improved calculation results of the fundamental wave amplitude of the flux and the finite element simulation results, it is verified that the present invention reduces the calculation error of the flux by improving the model, so that the calculation result of the no-load flux is closer to the actual value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the specific position of the air gap center and the inner diameter of the stator core of the flux reversal motor.

[0029] Figure 2 Schematic diagram of the motor stator slot opening angle α.

[0030] Figure 3 It is a schematic diagram comparing the magnetic flux linkage results obtained by calculating the magnetic flux harmonics of each order at the center of the motor's physical air gap and the inner diameter of the stator core with the finite element simulation results when the slot opening remains unchanged.

[0031] Figure 4 Schematic diagram of the comparison between the magnetic flux results calculated before and after the stator slot coefficient is introduced when the magnetic flux density is taken at the inner diameter of the stator core and the finite element simulation results.

[0032] Figure 5 It is a schematic diagram comparing the traditional calculation results of the fundamental wave amplitude of the magnetic flux under the change of the stator slot opening angle, the calculation results of the fundamental wave amplitude of the magnetic flux after improvement and the finite element simulation results. DETAILED DESCRIPTION

[0033] In order to describe the present invention more specifically, the technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] The present invention provides a method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect, comprising the following steps:

[0035] (1) The magnetic field modulation motor has an air gap filtering effect. Compared with the traditional flux calculation model that uses the magnetic flux harmonic component at the center of the motor's physical air gap, the improved flux calculation model of the present invention uses the magnetic flux harmonic component at the inner diameter of the stator core, such as Figure 1 As shown, it is closer to the actual harmonic component of magnetic density that enters the stator core and interlinks with the winding.

[0036] The air gap of the magnetic field modulated permanent magnet motor and the spatial structure of the permanent magnet have a filtering effect on the air gap magnetic flux at the center of the physical air gap, so that the harmonic components of the magnetic flux that actually enter the core and interlink with the winding are different from the harmonic components of the magnetic flux at the center of the physical air gap, and the harmonic components of the magnetic flux close to the inner diameter of the stator core are closer to the harmonic components of the magnetic flux that actually enter the stator core and interlink with the winding. In this embodiment, we use finite element simulation to obtain magnetic flux waveforms taken from the center of the physical air gap and the inner diameter of the stator core, and perform spectrum analysis on the magnetic flux waveform to obtain the amplitudes of each order of no-load magnetic flux at different positions.

[0037] The traditional flux calculation model uses the magnetic flux density value at the center of the motor's physical air gap to calculate the fundamental amplitude of the flux. ψ p The expression is:

[0038]

[0039] in: ψ p It represents the fundamental amplitude of flux linkage of magnetic field modulated permanent magnet motor. r g is the motor physical air gap radius, l sk is the axial length of the motor, N s is the number of series turns of each phase armature winding, k n For the n The winding coefficient of the order, B n The center of the motor's physical air gap n The harmonic amplitude of magnetic density of order; if and only if | iP m ± P r |= J At that time, n The magnetic flux corresponding to the order harmonic is not zero, that is, the order harmonic is the working harmonic. n is the harmonic order under certain conditions and n =| iP m ± P r |= J , P is the number of armature winding pole pairs,P m is the number of permanent magnet pole pairs, P r is the number of motor rotor teeth, i represents the order of magnetic density harmonics, j is the order of the stator slot coefficient.

[0040] Improved flux calculation model The flux fundamental amplitude is calculated by taking the flux density value at the inner diameter of the motor stator core ψ p The expression is:

[0041]

[0042] in: D s is the inner diameter of the stator core, B sn The inner diameter of the stator core n The harmonic amplitude of magnetic density of order.

[0043] Comparing the contribution of magnetic flux harmonics of various orders to the flux linkage, including the calculation results of the two flux fundamental wave amplitudes mentioned above and the finite element simulation results, it is revealed that there is an air gap filtering effect in the magnetic field modulated permanent magnet motor. It is verified that the flux linkage calculation error can be reduced by selecting the magnetic flux harmonic component at the inner diameter position of the stator core to calculate the flux linkage, thereby reducing the influence of the air gap filtering effect on the flux linkage calculation.

[0044] (2) There is a stator slot effect in the magnetic field modulation motor. By adding the stator slot coefficient, the influence of the stator slot opening on the magnetic flux calculation of the magnetic field modulation permanent magnet motor can be reduced.

[0045] We usually assume that the conductors are evenly distributed in the stator slots. The magnetic lines of force entering the slots pass through the coils and enter the stator teeth. After the stator is slotted, the winding function of the stator armature is N ( q ) changes, so that the no-load magnetic flux entering the slot cannot fully interlink with all the conductor coils in the slot, thus affecting the calculation of magnetic flux.

[0046] After the stator is slotted, the slot opening angle α is as follows Figure 2 As shown, the winding function N ( q ) no longer undergoes a sudden change, and it is approximately considered to change uniformly and linearly along the notch. The winding function N ( q )Any n The expression of the amplitude of the harmonic component is:

[0047]

[0048] Where: α represents the stator slot opening angle.

[0049] Thus, we can define the n Stator slot coefficient of order k nα The expression is:

[0050]

[0051] in: k nα Indicates n Stator slot coefficient of order, n is the harmonic order under certain conditions and n =| iP m ± P r |= J .

[0052] After considering the influence of stator slotting, the flux amplitude generated by each order of flux density harmonic components is multiplied by the stator slot coefficient of the corresponding order, and the flux amplitudes generated by the corrected flux density harmonic components of each order are added together to obtain the calculation result of the flux fundamental wave amplitude considering the stator slot coefficient.

[0053] By comparing the contributions of each order of magnetic flux harmonics to the flux linkage, including the calculation results of the fundamental wave amplitude of the flux linkage without introducing the stator slot coefficient, the calculation results of the fundamental wave amplitude of the flux linkage with introducing the stator slot coefficient and the finite element simulation results, the slotting effect of the magnetic field modulation motor is revealed. It is verified that the error in flux linkage calculation can be reduced by considering the stator slot coefficient, and the influence of the stator slot effect on the flux linkage calculation can be reduced.

[0054] (3) The air gap filtering effect and stator slot effect of the magnetic field modulation permanent magnet motor are considered at the same time, the magnetic flux density value position is changed and the stator slot coefficient is introduced, and an improved flux calculation model is established to calculate the fundamental amplitude of the magnetic flux of the magnetic field modulation permanent magnet motor, thereby reducing the calculation error of the fundamental amplitude of the magnetic flux of the magnetic field modulation permanent magnet motor.

[0055] Improved no-load phase flux fundamental amplitude ψ p The expression is:

[0056]

[0057] Comparing the traditional calculation results of the fundamental wave amplitude of the flux, the improved calculation results of the fundamental wave amplitude of the flux and the finite element simulation results, it is verified that the calculation error of the flux can be reduced by improving the calculation model, making the calculation results of the no-load flux closer to the actual value.

[0058] In order to verify the superiority of the flux calculation method of the present invention, we conducted an experimental verification. In the experiment, a 12-slot 14-pole flux reversal permanent magnet motor was used as an example. The specific parameters are shown in Table 1:

[0059] Table 1

[0060]

[0061] like Figure 3 As shown in the figure, the stator slot opening remains unchanged, and the position of the magnetic flux harmonic value is changed. The figure includes the calculation results of the magnetic flux fundamental wave amplitude when the magnetic flux is taken at the center of the physical air gap, the calculation results of the magnetic flux fundamental wave amplitude when the magnetic flux is taken at the inner diameter of the stator core, and the finite element simulation results; the magnetic flux fundamental wave amplitude when the magnetic flux is taken at the center of the physical air gap is 0.1122Wb, the magnetic flux fundamental wave amplitude when the magnetic flux is taken at the inner diameter of the stator core is 0.0972Wb, and the finite element simulation result of the magnetic flux fundamental wave amplitude is 0.0913Wb. After changing the magnetic flux selection position, the error between the theoretical calculation value of the magnetic flux fundamental wave amplitude and the finite element simulation result is reduced from 22.9% to 5.7%. This result reveals that there is an air gap filtering effect in the magnetic field modulation permanent magnet motor, and verifies that the magnetic flux calculation error can be reduced by selecting the magnetic flux at the inner diameter position of the stator core, and the influence of the air gap filtering effect on the magnetic flux calculation can be reduced.

[0062] like Figure 4 As shown, the magnetic flux harmonic value is taken at the inner diameter of the stator core, and the stator slot opening angle is 12 ° , the figure includes the calculation results of the fundamental amplitude of the flux before the introduction of the stator slot coefficient, the calculation results of the fundamental amplitude of the flux after the introduction of the stator slot coefficient, and the finite element simulation results; the fundamental amplitude of the flux before the introduction of the stator slot coefficient is 0.0972Wb, the fundamental amplitude of the flux after the introduction of the stator slot coefficient is 0.0910Wb, and the finite element simulation result of the fundamental amplitude of the flux is 0.0913Wb. After the introduction of the stator slot coefficient, the error between the theoretical calculation value of the fundamental amplitude of the flux and the finite element simulation result is reduced from 5.7% to 0.4%. This result reveals the slot effect of the magnetic field modulation motor and verifies that the error of the flux calculation can be reduced by considering the stator slot coefficient, and the influence of the stator slot effect on the flux calculation can be reduced.

[0063] like Figure 5 As shown, the stator slot opening angle is from 2 ° to 12 ° The figure compares the traditional calculation results of the fundamental wave amplitude of the flux, the improved calculation results of the fundamental wave amplitude of the flux and the finite element simulation results. The error between the calculation results obtained by the traditional flux calculation model and the simulation value is 14.2%~22.9%, and the error between the calculation results using the improved flux calculation model and the finite element simulation value is within 0.6%. This result verifies that the improved model can greatly reduce the error in flux calculation, making the calculation results of no-load flux more consistent with the actual value.

[0064] The above description of the embodiments is to facilitate the understanding and application of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art to the present invention based on the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect, comprising the following steps: (1) Considering the air gap filtering effect of the magnetic field modulated permanent magnet motor, the harmonic component of the magnetic flux density at the inner diameter of the stator core is selected to calculate the flux linkage. The specific implementation method is as follows: first, the magnetic flux waveforms taken from the center of the motor's physical air gap and the inner diameter of the stator core are obtained through finite element simulation, and the spectrum analysis of the magnetic flux waveform is performed to obtain the amplitudes of each order of no-load magnetic flux at different positions; then, the magnetic flux value extracted from the center of the motor's physical air gap is used to calculate the fundamental amplitude of the magnetic flux linkage, and the magnetic flux value extracted from the inner diameter of the motor's stator core is used to calculate the fundamental amplitude of the magnetic flux linkage; the above two calculation results of the fundamental amplitude of the magnetic flux linkage are compared with the finite element simulation results to verify that by selecting the harmonic component of the magnetic flux density at the inner diameter of the stator core, the error of the magnetic flux linkage calculation can be reduced, and the influence of the air gap filtering effect on the magnetic flux linkage calculation can be reduced; (2) Considering the stator slot effect of the magnetic field modulation permanent magnet motor, the flux linkage is calculated by adding the stator slot coefficient; (3) Taking into account the air gap filtering effect and stator slot effect of the magnetic field modulation permanent magnet motor, the magnetic flux density value location is changed to the inner diameter of the stator core and the stator slot coefficient is introduced to establish an improved flux calculation model and use the model to calculate the fundamental amplitude of the flux of the magnetic field modulation permanent magnet motor.

2. The method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect according to claim 1 is characterized in that: The expression for calculating the fundamental amplitude of the flux linkage using the magnetic flux value extracted at the center of the motor's physical air gap is as follows: Where: p Represents the fundamental amplitude of the flux linkage of the magnetic field modulation permanent magnet motor, r g is the motor physical air gap radius, l sk is the axial length of the motor, N s is the number of series turns of each phase armature winding, k n is the winding coefficient of the nth order, B n is the nth order magnetic flux harmonic amplitude at the center of the motor physical air gap; if and only if |iP m ±P r |=jP, the flux linkage corresponding to the nth order harmonic is not zero, that is, this harmonic is a working harmonic, n is the harmonic order under specific conditions and n=|iP m ±P r |=jP, P is the number of armature winding poles, P m is the number of permanent magnet pole pairs, P r is the number of motor rotor teeth, i represents the order of magnetic flux harmonic, and j is the order of stator slot coefficient.

3. The method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect according to claim 1 is characterized in that: The expression for calculating the fundamental amplitude of flux linkage using the magnetic flux value extracted from the inner diameter of the motor stator core is as follows: Where: p It represents the fundamental amplitude of flux linkage of magnetic field modulated permanent magnet motor, D s is the inner diameter of the stator core, l sk is the axial length of the motor, N s is the number of series turns of each phase armature winding, k n is the winding coefficient of the nth order, B sn is the nth order magnetic flux harmonic amplitude at the inner diameter of the stator core; if and only if |iP m ±P r |=jP, the flux linkage corresponding to the nth order harmonic is not zero, that is, this harmonic is a working harmonic, n is the harmonic order under specific conditions and n=|iP m ±P r |=jP, P is the number of armature winding poles, P m is the number of permanent magnet pole pairs, P r is the number of motor rotor teeth, i represents the order of magnetic flux harmonic, and j is the order of stator slot coefficient.

4. The method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect according to claim 1 is characterized in that: The specific implementation method of step (2) is as follows: the stator slot coefficient is defined according to the amplitude of each order harmonic component of the winding function, the flux amplitude generated by each order of the magnetic flux harmonic component after considering the influence of the stator slot needs to be multiplied by the stator slot coefficient of the corresponding order, and the flux amplitude generated by each order of the magnetic flux harmonic component after correction is added to obtain the calculation result of the flux fundamental wave amplitude after considering the stator slot coefficient; By comparing the calculation results of the fundamental wave amplitude of the flux before and after the introduction of the stator slot coefficient with the finite element simulation results, it is verified that the addition of the stator slot coefficient can reduce the flux calculation error and reduce the influence of the stator slot effect on the flux calculation.

5. The method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect according to claim 1 is characterized in that: The expression of the stator slot coefficient is as follows: Where: k nα represents the nth order stator slot coefficient, α represents the stator slot opening angle, n is the harmonic order under specific conditions and n=|iP m ±P r |=jP, P is the number of armature winding poles, P m is the number of permanent magnet pole pairs, P r is the number of motor rotor teeth, i represents the order of magnetic flux harmonic, and j is the order of stator slot coefficient.

6. The method for calculating the flux linkage of a magnetic field modulation permanent magnet motor based on air gap filtering effect and stator slotting effect according to claim 1, characterized in that: The improved magnetic flux calculation model in step (3) is expressed as follows: Where: p It represents the fundamental amplitude of flux linkage of magnetic field modulated permanent magnet motor, D s is the inner diameter of the stator core, l sk is the axial length of the motor, N s is the number of series turns of each phase armature winding, k n is the winding coefficient of the nth order, B sn is the nth order magnetic flux harmonic amplitude at the inner diameter of the stator core, k nα represents the stator slot coefficient of the nth order; if and only if |iP m ±P r |=jP, the flux linkage corresponding to the nth order harmonic is not zero, that is, this harmonic is a working harmonic, n is the harmonic order under specific conditions and n=|iP m ±P r |=jP, P is the number of armature winding poles, P m is the number of permanent magnet pole pairs, P r is the number of motor rotor teeth, i represents the order of magnetic flux harmonic, and j is the order of stator slot coefficient.

7. A computer device comprising a memory and a processor, characterized in that: The memory stores a computer program, and the processor is used to execute the computer program to implement a method for calculating the flux linkage of a magnetic field modulated permanent magnet motor based on air gap filtering effect and stator slotting effect as described in any one of claims 1 to 6.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it implements a method for calculating the flux linkage of a magnetic field modulated permanent magnet motor based on air gap filtering effect and stator slotting effect as described in any one of claims 1 to 6.

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