Permanent magnet magnetic permeability coefficient calculation method based on finite element simulation

Abstract

The invention discloses a finite element simulation-based permanent magnet permeability coefficient calculation method. The method comprises the following steps of S1, establishing a simulation model of a permanent magnet and setting a simulation boundary; s2, endowing the permanent magnet with material characteristic parameters and distributing simulation parameters; s3, setting solving parameters, performing automatic mesh generation, performing static magnetic field simulation, and performing calculation to obtain numerical values of magnetic flux density Bd and magnetic field intensity Hd; s4, selecting a corresponding constant k according to the ratio of the maximum size L in the magnetization direction of the permanent magnet to the maximum size T in the direction perpendicular to the magnetization direction; and S5, calculating the magnetic conductance coefficient through a formula: # imgabs0 #. According to the method, a simulation model of the permanent magnet is established, material characteristic parameters are given to the permanent magnet, simulation parameters are distributed, then numerical values of the magnetic flux density Bd and the magnetic field intensity Hd are obtained through calculation, a corresponding constant k is selected according to the ratio of the maximum size L in the magnetization direction of the permanent magnet to the maximum size T in the direction perpendicular to the magnetization direction, and then the magnetic conductance coefficient is obtained through # imgabs1 #. Calculation is convenient, accurate and efficient.

Description

Technical Field

[0001] The invention relates to the technical field of permanent magnets, and in particular to a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation. Background Art

[0002] NdFeB permanent magnets are widely used in various industries such as 3C consumer electronics and new energy vehicles, which have requirements for the operating temperature environment of permanent magnets; and the maximum operating temperature of permanent magnets is closely related to the magnetic permeability coefficient of permanent magnets, which is also called the demagnetization coefficient.

[0003] In the prior art, the permeability coefficient of magnets can only be calculated by formulas for regular magnets such as cuboids, cylinders, tori, and spheres; however, in actual production applications, there are a large number of irregular shaped magnets, so the permeability coefficient of the magnet cannot be obtained by using the existing formula calculation method. Therefore, there is an urgent need for a method that can accurately calculate the permeability coefficient of permanent magnets with irregular shapes, which is a problem that urgently needs to be solved. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, which can quickly and effectively calculate the magnetic permeability coefficient of regular and irregular permanent magnets, and the calculation is convenient and the numerical value is accurate.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, comprising the following steps:

[0006] S1. Establish a simulation model of a permanent magnet and set simulation boundaries;

[0007] S2, assigning material characteristic parameters to the permanent magnet and allocating simulation parameters;

[0008] S3, set the solution parameters, automatically mesh, perform static magnetic field simulation, and use the edited field calculator command to calculate the values ​​of magnetic flux density Bd and magnetic field intensity Hd;

[0009] S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k;

[0010] S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

[0011]

[0012] Furthermore, the permanent magnet is a sintered NdFeB permanent magnet.

[0013] Furthermore, in step S1, establishing the simulation model includes establishing it in finite element simulation software, or directly importing the simulation model of a permanent magnet of any shape into the finite element simulation software.

[0014] Furthermore, in step S1: outside the established permanent magnet model, the value of the simulation boundary is set to be 1000 times larger than the size of the permanent magnet model.

[0015] Furthermore, in step S2, the material properties given to the permanent magnet include: relative magnetic permeability curves of remanence and magnetic induction coercivity, and magnetization direction.

[0016] Further, in step S3, the field calculator command is edited as follows:

[0017] Bd calculation command: Scl: / (Integrate(Volume(Box1),Mag(<Bx,By,Bz> )),Integrate(Volume(Box1),1));

[0018] Hd calculation command: Scl: / (Integrate(Volume(Box1),Mag(<Hx,Hy,Hz> )),Integrate(Volume(Box1),1)); where Box1 represents the volume of the permanent magnet.

[0019] Furthermore, in step S3, it is necessary to convert the values ​​of Bd and Hd calculated by the edited field calculator command into units:

[0020] To convert the Hd value, multiply the SI Tesla (T) value by 10000 to obtain the CGS Gauss (Gs) value. To convert the Hd value, divide the SI ampere per meter (A / m) value by 79.6 to obtain the CGS Oersted (Oe) value.

[0021] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0022] The method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation of the present invention establishes a simulation model of the permanent magnet through finite element software, assigns material characteristic parameters to the permanent magnet and allocates simulation parameters, then performs static magnetic field simulation and uses the edited field calculator command to calculate the values ​​of the magnetic flux density Bd and the magnetic field intensity Hd, and then selects the corresponding constant k according to the ratio of the maximum dimension L of the permanent magnet in the magnetization direction to the maximum dimension T perpendicular to the magnetization direction, and finally calculates the value of the magnetic flux density Bd and the magnetic field intensity Hd through the formula The permeability coefficient is obtained, and the calculation is simple and convenient, and is applicable to regular and irregular permanent magnets. The calculation results are accurate and efficient, and can well meet actual use needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings:

[0024] Figure 1 It is a schematic diagram of the relationship between the BH curve of the permanent magnet and the magnetic permeability coefficient;

[0025] Figure 2 It is a schematic diagram comparing the working point and inflection point of the permanent magnet at different temperatures;

[0026] Figure 3 A schematic diagram of a flow chart of an embodiment of the present invention;

[0027] Figure 4 The simulation model of the regular rectangular parallelepiped shape in the first embodiment of the present invention;

[0028] Figure 5 The simulation model of the rectangular regular shape in the second embodiment of the present invention;

[0029] Figure 6 It is a simulation model of a regular cylindrical shape in the third embodiment of the present invention;

[0030] Figure 7 It is a simulation model of a regular cylindrical shape in the fourth embodiment of the present invention;

[0031] Figure 8 It is a simulation model of the special-shaped permanent magnet model in the fifth embodiment of the present invention;

[0032] Fig. 9 It is a simulation model of the special-shaped permanent magnet model in the sixth embodiment of the present invention;

[0033] Fig.10 This is a simulation model of the special-shaped permanent magnet model in the seventh embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0035] based on Figure 1, the present invention needs to calculate the permeability coefficient of the permanent magnet, and the definition of the permeability coefficient is as follows: when the permanent magnet works as a magnetic field source or magnetic force source, it generates a magnetic field in a certain space and works in an open circuit state. The permanent magnet in the open circuit state is under the action of its own demagnetization field, so the magnetic induction intensity of the permanent magnet in its working state is not at the Br point in the closed circuit state, but at a point on the BH curve that is lower than Br. This point is called the working point of the permanent magnet, and the line connecting it with the origin is called the magnetic wire or load line, and the slope of this line is named the permeability coefficient.

[0036] The irreversible loss of permanent magnet flux at different temperatures has a corresponding relationship with the relative position of the working point and the inflection point of the load line of the permanent magnet on the BH curve at different temperatures. Therefore, the maximum operating temperature of the permanent magnet can be evaluated based on the relative position relationship between the working point and the inflection point on the BH curve at each temperature. Therefore, the maximum operating temperature of the permanent magnet has a direct relationship with the permeability coefficient value.

[0037] based on Figure 2 , based on the permeability coefficient Pc. When the working point is above the inflection point S0 and far away from the inflection point, such as points S3, S4, and S5, the permanent magnet will not decay its magnetic properties when it returns to room temperature after a high temperature. If the working point is below the inflection point, such as points S1 and S2, the permanent magnet will decay its magnetic properties when it returns to room temperature after a high temperature, and it cannot recover to the performance before the high temperature.

[0038] See also Figure 3 The present invention discloses a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, comprising the following steps:

[0039] S1. Establish a simulation model of a permanent magnet and set simulation boundaries;

[0040] S2, assigning material characteristic parameters to the permanent magnet and allocating simulation parameters;

[0041] S3, set the solution parameters, automatically mesh, perform static magnetic field simulation, and use the edited field calculator command to calculate the values ​​of magnetic flux density Bd and magnetic field intensity Hd;

[0042] S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k;

[0043] S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

[0044]

[0045] Several embodiments are listed below for specific description.

[0046] Embodiment 1

[0047] based on Figure 4 , a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, comprising the following steps:

[0048] S1. Establish a simulation model of a 2.80x2.50x2.50mm permanent magnet in a regular rectangular shape in Maxwell, and set the simulation solution domain size to 1000 times that of the simulation model.

[0049] S2. Assign N52 grade material to the permanent magnet, assign torque simulation parameters to the permanent magnet, and set the magnetization direction in the direction of the 2.50mm magnet thickness;

[0050] S3, set the solution parameters, automatic meshing, and then edit the field calculator command after static magnetic field simulation;

[0051] Specifically, in this embodiment, the values ​​of the magnetic flux density Bd and the magnetic field intensity Hd calculated using the edited field calculator command are as follows: Bd=0.947674 (T), Hd=406219.09 (A / m).

[0052] Then, the Bd and Hd in step S3 are converted into unit values, 1T = 10000Gs, 1A / m = 1 / 79.6Oe;

[0053] At this time; Bd = 0.947674 (T) x 10000 = 9476.74 (Gs); Hd = 406219.09 (A / m) / 79.6 = 5103.25 (Oe);

[0054] S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k;

[0055] In step S4, the constant K is obtained using the following Table 1:

[0056] L / T Constant L / T<0.1 0.65 0.1≤L / T<0.2 0.83 0.2≤L / T<0.3 1.03 0.3≤L / T<0.4 1.12 0.4≤L / T<0.5 1.25 0.5≤L / T<0.6 1.3 0.6≤L / T<0.7 1.39 0.7≤L / T<0.8 1.46 0.8≤L / T<0.9 1.53 0.9≤L / T<1.0 1.60

[0057] Table 1

[0058] Specifically, in this embodiment, L / T=2.50 / 2.80=0.893, k=1.53;

[0059] S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

[0060]

[0061] In this embodiment: Pc = Bd / Hdxk = 9476.74 / 5103.25x1.53 = 2.841;

[0062] For comparison, according to the theoretical calculation formula:

[0063] Where a = 2.80, b = 2.50, L = 2.50;

[0064] Pc=2.849 was calculated.

[0065] In summary, the permanent magnet in the first embodiment is a regular rectangular parallelepiped, and the Pc value calculated by finite element simulation is 2.841, which is very consistent with the Pc value 2.849 calculated by the theoretical formula.

[0066] Embodiment 2

[0067] based on Figure 5 The difference between Example 2 and Example 1 is that after establishing a simulation model of a rectangular regular shape of a permanent magnet of 8.48x4.50x2.00 in Maxwell, the simulation Pc value calculated is 0.748, while the result calculated by the theoretical formula is 0.744, and the results between the two are very consistent.

[0068] Embodiment 3

[0069] based on Figure 6 , a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, comprising the following steps:

[0070] S1. Establish a simulation model of a cylindrical permanent magnet with a size of D10.00X7.50mm in Maxwell, and set the simulation domain size to 1000 times that of the model.

[0071] S2. Assign N52 grade material to the permanent magnet, assign torque simulation parameters to the permanent magnet simulation model, and set the magnetization direction to the axial direction of the magnet at 7.50 mm;

[0072] S3, set the solution parameters, automatic meshing, and then edit the field calculator command after static magnetic field simulation;

[0073] Specifically, in this embodiment, the values ​​of the magnetic flux density Bd and the magnetic field intensity Hd calculated using the edited field calculator command are as follows: Bd=0.909700 (T), Hd=447616.68 (A / m).

[0074] Then, the Bd and Hd in step S3 are converted into unit values, 1T = 10000Gs, 1A / m = 1 / 79.6Oe;

[0075] At this time; Bd = 0.909700 (T) x 10000 = 9097.00 (Gs); Hd = 447616.68 (A / m) / 79.6 = 5623.33 (Oe);

[0076] S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k in Table 1;

[0077] In step S4, the constant K is obtained by using the table in Table 1:

[0078] Specifically, in this embodiment, L / T=7.50 / 10.00=0.750, k=1.46;

[0079] S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

[0080]

[0081] In this embodiment: Pc = Bd / Hdxk = 9097.00 / 5623.33x1.46 = 2.362;

[0082] For comparison, according to the theoretical calculation formula:

[0083] Wherein, L = 7.5, R = 5;

[0084] Calculate Pc = 2.372;

[0085] In summary, the permanent magnet in the third embodiment is a regular cylindrical shape, and the Pc value calculated by finite element simulation is 2.362, which is very consistent with the result of Pc value 2.372 calculated by the theoretical formula.

[0086] Embodiment 4

[0087] based on Figure 7 The difference between Example 4 and Example 3 is that after establishing a simulation model of a cylindrical regular shape of a D5.00X0.55mm permanent magnet in Maxwell, the simulated Pc value calculated is 0.243, while the result calculated by the theoretical formula is 0.243, and the results between the two are consistent.

[0088] Based on the above four embodiments, the comparative data between the four embodiments are shown in the following table:

[0089]

[0090] Table 2

[0091] It can be seen from Table 2 that in calculating the permeability coefficient of some permanent magnets of conventional shapes, the error between the simulation calculation method of the present invention and the theoretical calculation method is between -0.41% and 0.62%, and the error is very small. Therefore, in actual calculation, the calculation method of the present invention can be used to quickly calculate the permeability coefficient of the permanent magnet to meet relevant needs.

[0092] Next, several embodiments are listed to illustrate the permeability coefficient of special-shaped permanent magnets.

[0093] Embodiment 5

[0094] based on Figure 8 , a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, comprising the following steps:

[0095] S1. Establish a 5.10*4.58*2.05 special-shaped permanent magnet model in Maxwell, and set the simulation solution domain size to 1000 times that of the special-shaped permanent magnet model;

[0096] S2. Assign N52 grade material to the permanent magnet, assign torque simulation parameters to the permanent magnet, and set the magnetization direction in the direction of 2.05 mm;

[0097] S3, set the solution parameters, automatic meshing, and then edit the field calculator command after static magnetic field simulation;

[0098] Specifically, in this embodiment, the values ​​of the magnetic flux density Bd and the magnetic field intensity Hd calculated using the edited field calculator command are as follows: Bd=0.587408 (T), Hd=710424.90 (A / m).

[0099] Then, the Bd and Hd in step S3 are converted into unit values, 1T = 10000Gs, 1A / m = 1 / 79.6Oe;

[0100] At this time; Bd = 0.587408 (T) x 10000 = 5874.08 (Gs), Hd = 710424.90 (A / m) / 79.6 = 8924.94 (Oe);

[0101] S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k in Table 1;

[0102] Specifically, in this embodiment, L / T=2.05 / 5.10=0.402, k=1.25;

[0103] S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

[0104]

[0105] In this embodiment: Pc = Bd / Hdxk = 5874.08 / 8924.94x1.25 = 0.823;

[0106] Since there is no theoretical calculation formula for the Pc value of special-shaped permanent magnets, it cannot be calculated directly. Therefore, the Pc value can only be measured to be 0.827, which is different from the Pc value 0.823 calculated by finite element simulation. The numerical error between the two is close to 0.

[0107] Embodiment 6

[0108] based on Fig. 9 , a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, comprising the following steps:

[0109] S1. Establish a 10.50*4.85*5.00 special-shaped permanent magnet model in Maxwell, and set the simulation solution domain size to 1000 times that of the special-shaped permanent magnet model;

[0110] S2. Assign N52 grade material to the permanent magnet, assign torque simulation parameters to the permanent magnet, and set the magnetization direction in the direction of 5.00 mm;

[0111] S3, set the solution parameters, automatic meshing, and then edit the field calculator command after static magnetic field simulation;

[0112] Specifically, in this embodiment, the values ​​of the magnetic flux density Bd and the magnetic field intensity Hd calculated using the edited field calculator command are as follows: Bd=0.937182 (T), Hd=414710.95 (A / m).

[0113] Then, the Bd and Hd in step S3 are converted into unit values, 1T = 10000Gs, 1A / m = 1 / 79.6Oe;

[0114] At this time; Bd = 0.937182 (T) x 10000 = 9371.82 (Gs), Hd = 414710.95 (A / m) / 79.6 = 5209.94 (Oe);

[0115] S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k in Table 1;

[0116] Specifically, in this embodiment, L / T=5.00 / 10.50=0.476, k=1.25;

[0117] S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

[0118]

[0119] In this embodiment: Pc = Bd / Hdxk = 9371.82 / 5209.94x1.25 = 2.249;

[0120] However, there is no theoretical calculation formula for the Pc value of special-shaped permanent magnets and it cannot be calculated directly. Therefore, the Pc value can only be 2.238 through actual measurement, which is very close to the Pc value of 2.249 obtained by finite element simulation calculation.

[0121] Embodiment 7

[0122] based on Fig.10 , a method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, comprising the following steps:

[0123] S1. Establish a 9.05*7.55*3.89 special-shaped permanent magnet model in Maxwell, and set the simulation solution domain size to 1000 times that of the special-shaped permanent magnet model;

[0124] S2. Assign N52 grade material to the permanent magnet, assign torque simulation parameters to the permanent magnet, and set the magnetization direction in the direction of 3.89 mm;

[0125] S3, set the solution parameters, automatic meshing, and then edit the field calculator command after static magnetic field simulation;

[0126] Specifically, in this embodiment, the values ​​of the magnetic flux density Bd and the magnetic field intensity Hd calculated using the edited field calculator command are as follows: Bd=0.608501 (T), Hd=675679.05 (A / m).

[0127] Then, the Bd and Hd in step S3 are converted into unit values, 1T = 10000Gs, 1A / m = 1 / 79.6Oe;

[0128] At this time; Bd = 0.608501 (T) x 10000 = 6085.01 (Gs), Hd = 675679.05 (A / m) / 79.6 = 8488.43 (Oe);

[0129] S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k in Table 1;

[0130] Specifically, in this embodiment, L / T=3.89 / 9.05=0.430, k=1.25;

[0131] S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

[0132]

[0133] In this embodiment: Pc = Bd / Hdxk = 6085.01 / 8488.43x1.25 = 0.896;

[0134] However, there is no theoretical calculation formula for the Pc value of the special-shaped permanent magnet and it cannot be calculated directly. Therefore, the Pc value can only be 0.893 through actual measurement, which is very close to the Pc value of 0.896 obtained by finite element simulation calculation.

[0135] The comparative data of the above three implementations are shown in the following table:

[0136]

[0137] Table 3

[0138] It can be seen from the above table that for the magnet coefficients of some special-shaped permanent magnets, the error between the simulation calculation method of the present invention and the actual measurement value is between -0.52% and 0.47%, and the error is very small. Therefore, in actual calculations, the calculation method of the present invention can also be used to quickly calculate special-shaped permanent magnets.

[0139] In summary, the method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation of the present invention can be applied not only to some conventional shapes, but also to the calculation of the magnetic permeability coefficient of special-shaped permanent magnets. Therefore, the present invention can be used to calculate the magnetic permeability coefficient of a permanent magnet of any shape. The method is simple and fast, and the result obtained is very accurate.

[0140] Of course, the embodiment of the present invention is implemented based on Maxwell software, and the present invention can also be implemented by other finite element simulation software, such as Comsol and JMAG, etc., as long as the relevant functions can be realized.

[0141] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation, characterized in that: The steps include: S1. Establish a simulation model of a permanent magnet and set simulation boundaries; S2, assigning material characteristic parameters to the permanent magnet and allocating simulation parameters; S3, set the solution parameters, automatically mesh, perform static magnetic field simulation, and use the edited field calculator command to calculate the values ​​of magnetic flux density Bd and magnetic field intensity Hd; S4. According to the ratio of the maximum dimension L in the magnetization direction of the permanent magnet to the maximum dimension T perpendicular to the magnetization direction, select the corresponding constant k; S5. Substitute Bd, Hd, and k into the following formula to calculate the permeability coefficient Pc of the permanent magnet:

2. The method for calculating the magnetic permeability coefficient of a permanent magnet based on finite element simulation according to claim 1, characterized in that: The permanent magnet is a sintered NdFeB permanent magnet.

3. The method for calculating magnetic permeability based on finite element simulation according to claim 1, characterized in that: In step S1 , the establishment of the simulation model includes establishing it in finite element simulation software, or directly importing the simulation model of a permanent magnet of any shape into the finite element simulation software.

4. The method for calculating the magnetic permeability coefficient based on finite element simulation according to claim 1, characterized in that: In step S1: outside the established permanent magnet model, the value of the simulation boundary is set to be 1000 times larger than the size of the permanent magnet model.

5. The method for calculating magnetic permeability based on finite element simulation according to claim 1, characterized in that: In step S2, the material properties given to the permanent magnet include: relative magnetic permeability curve of remanence and magnetic induction coercivity, and magnetization direction.

6. The method for calculating magnetic permeability based on finite element simulation according to claim 1, characterized in that: In step S3, edit the field calculator command as follows: Bd calculation command: Scl: / (Integrate(Volume(Box1),Mag(<Bx,By,Bz> )),Integrate(Volume(Box1),1)); Hd calculation command: Scl: / (Integrate(Volume(Box1),Mag(<Hx,Hy,Hz> )),Integrate(Volume(Box1),1)); where Box1 represents the volume of the permanent magnet.

7. The method for calculating magnetic permeability based on finite element simulation according to claim 1, characterized in that: In step S3, it is necessary to convert the values ​​of Bd and Hd calculated by the edited field calculator command into units: To convert the Hd value, multiply the SI Tesla (T) value by 10000 to obtain the CGS Gauss (Gs) value. To convert the Hd value, divide the SI ampere per meter (A / m) value by 79.6 to obtain the CGS Oersted (Oe) value.

Images