JP2003098241A - System for evaluating iron loss in electro-magnetic field analysis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a Maxwell equation to evaluate an iron loss, taking anisotropy in magnetic permeability or reluctivity of a steel material into account. SOLUTION: An objective area is divided into a plurality of micro-areas by an area dividing means 1, and an angle θ formed by a predetermined direction of a steel sheet and a direction of magnetic flux in the each area is imparted by a magnetic flux density vector determining means 2. Data of magnetic flux density (H-B curve) in a magnetic field and the iron loss (W-B curve) are stored in a database 3 using the angle θ and a stress σ as parameters. The magnetic flux density vector determining means 2 executes convergence calculation by compounding with the Maxwell equation, based on the H-B curve, and founds the magnetic flux density. An interpolation calculation means 4 calls out the W-B curve corresponding to the magnetic flux density, and interpolation-corrects it using the angle θ and the stress σ as the parameters. The iron loss Wi within the micro-area ai is found, based on the corrected W-B curve, in a micro-area loss calculating means 5. Total of the iron losses Wi is found to bring the iron loss as the whole, in an iron loss totalizing means 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron loss evaluation system for electromagnetic field analysis using electromagnetic field analysis, and more particularly to an iron loss evaluation method that takes into consideration the anisotropy of electromagnetic characteristics of a steel sheet.

[0002]

2. Description of the Related Art Conventionally, an electromagnetic field analysis method based on Maxwell's equation has been used for iron loss evaluation of steel sheets and the like. A computer is used for electromagnetic field analysis, and the shape of the steel sheet, the size of the minute region divided for calculation, the magnetic flux density B with respect to the magnetic field H, the stress σ applied to the steel sheet, the frequency, etc.
It is used as a parameter condition for physical quantity for obtaining a solution calculated by a computer.

That is, taking these conditions into consideration,
A computer solution of the Maxwell equation is obtained. In the computer solution of the Maxwell equation, the iron loss is obtained in consideration of the data (B-W curve) of the iron loss W measured corresponding to the magnetic flux density B.

For example, FIG. 7 is a block diagram showing the flow of a core loss numerical calculation routine executed according to the prior art. First, the steel sheet shape 71, the minute area division 72, the frequency 73, etc.
A condition for obtaining a solution is given, and a numerical solution of Maxwell's equation 75 is obtained by calculation.

Data (B-W curve) 76 of the iron loss W of the steel material in a minute region measured corresponding to the distribution 77 of the magnetic flux density B is given to the above numerical solution, and from the distribution 78 of the iron loss W, the steel plate is obtained. The overall iron loss 79 is calculated. Here, the angle θ formed between the predetermined direction and the magnetic flux direction is fixed and isotropic permeability is assumed.

Here, a method of solving the Maxwell equation will be briefly described. As is clear from many known documents, the Maxwell equation is given by (Equation 1) below.

[0007]

[Equation 1]

Here, B, H, D, E, and J are magnetic flux density, magnetic field, electric flux density, electric field, and current density, respectively. Further, ρ is the charge density. B, H, D, E, and J have the following relationship (Equation 2).

[0009]

[Equation 2]

Here, μ, ε and σ are magnetic permeability, permittivity and conductivity, respectively.

On the other hand, according to "Finite Element Method of Electrical Engineering" by Takayoshi Nakata and Norio Takahashi (Morikita Publishing, 1982),
The electromagnetic field analysis is described in detail. According to the document, ∂D / ∂t is ignored. Since the divergence of the magnetic flux is always zero, it is continuous, and the magnetic vector potential A is given by the following equation.

[0012]

[Equation 3]

From these equations,

[0014]

[Equation 4]

Is obtained. Therefore,

[0016]

[Equation 5]

Is obtained. Here, -grad φ = E, J ₀ is a forced current density from the outside, Je is an eddy current density, and the magnetic resistivity “ν” given by the tensor amount is “ν” = 1 / “μ”. (Equation 5) is a Galerkin method
It is solved two-dimensionally and three-dimensionally by d). In practice, magnetic permeability is generally anisotropic. However, in the conventional iron loss evaluation method, numerical analysis was performed assuming that the magnetic permeability was isotropic, and a solution was obtained.

A numerical solution of the magnetic flux density B with respect to the magnetic field H can be obtained by applying the data of the H-B curve in each minute region of the steel sheet to the Maxwell equation.
Here, the H-B curve is assumed to have isotropic permeability,
The data is obtained by measuring in advance using the stress σ _i (i = 1, 2, ... N) applied to the steel sheet as a parameter. The H-B curve data is prepared for each stress value set at appropriate intervals and stored in the database.

Here, the numerical solution of the magnetic flux density B with respect to the magnetic field H, which corresponds to the stress σ that is an intermediate value between the stress σ _j and the stress σ _{j + 1} , can be obtained by interpolation approximation or series approximation. In this way, from the magnetic flux density B with the stress σ _j (i = 1, 2, 3 ... N) as a parameter, which is obtained for each minute region with respect to the given magnetic field strength H, the magnetic flux density in each minute region is obtained. Distribution is required.

On the other hand, the relationship between the magnetic flux density B and the iron loss W is the stress σ
Is measured in advance as a parameter and stored in the database in the form of a WB curve. Therefore, if the magnetic flux density distribution obtained by the numerical calculation is applied to the WB curve previously measured using the stress σ as a parameter and stored in the database, the iron loss of the entire steel sheet with respect to the given magnetic field strength H is reduced. Calculated by numerical calculation.

[0021]

In the above-mentioned prior art, in the electromagnetic field analysis for obtaining the iron loss, since the magnetic permeability is calculated as isotropic, the difference in the magnetic permeability existing in the actual steel material is calculated. However, there is a drawback in that the difference between the measured value and the calculated value cannot be ignored, and the iron loss cannot be sufficiently evaluated.

In view of the above-mentioned problems, the present invention eliminates the above-mentioned drawbacks of the prior art while following the conventional analysis method, and takes into consideration the anisotropy of the physical property parameter of the steel material. The purpose is to be able to provide a loss evaluation method.

[0023]

An iron loss evaluation system for electromagnetic field analysis according to the present invention comprises a region dividing means for dividing an entire target region of a steel material into a plurality of minute regions, and a predetermined plate steel sheet in the minute regions. A first database that stores the data of the magnetic field (H-B curve) with respect to the magnetic flux density by using the angle θ between the direction and the magnetic flux density direction as an anisotropy parameter and provides the data for determining the magnetic flux density vector. , A magnetic flux that determines the angle θ and the magnitude B of the magnetic flux density based on the Maxwell equation in the minute divided region based on the data (H-B curve) stored in the first database. Second data provided for density loss determination means and iron loss (WB curve) data with respect to magnetic flux density using the angle θ as an anisotropy parameter and provided for iron loss calculation. And an interpolating and interpolating means for calculating an interpolated value of the WB curve with respect to an arbitrary angle θ using the iron loss (WB curve) stored in the second database as data. It is characterized by comprising an iron loss calculating means for calculating the iron loss of each of the minute areas using a value, and an iron loss summing means for obtaining the sum of the iron loss of each of the minute areas. Further, another feature of the present invention is that a region dividing means for dividing the entire target region of the steel material into a plurality of minute regions, and a predetermined direction of the steel sheet and a direction of magnetic flux density in the minute regions. Magnetic field (H-B curve) with respect to magnetic flux density with the angle θ between them as an anisotropy parameter
And the iron loss (WB curve) data are stored, and based on the database provided for the calculation of the iron loss and the HB curve stored in the database, the Maxwell equation in the minute region Based on the above, the angle θ and the magnetic flux density vector determining means for determining the magnitude B of the magnetic flux density, and an arbitrary angle θ with the iron loss (WB curve) for the magnetic flux density stored in the database as data. For the WB curve, an interpolating interpolation means for calculating an interpolated value of the WB curve, an iron loss calculating means for calculating the iron loss of each of the minute regions using the interpolated value, and an iron loss of each of the minute regions. It is characterized in that it is configured by including an iron loss summing means for obtaining the sum. Further, the other feature of the present invention is a region dividing means for dividing the entire target region of the steel material into a plurality of minute regions, a predetermined direction of the steel sheet in the minute region and a direction of magnetic flux density. Between the magnetic flux density (H
-B curve) and iron loss (WB curve) data are stored and provided to the calculation of iron loss, and the minute region based on the H-B curve stored in the database. At Maxwell's equation and the stress σ
Based on the angle θ and the magnetic flux density vector determining means for determining the magnitude B of the magnetic flux density, and an arbitrary angle using the iron loss (WB curve) for the magnetic flux density stored in the database as data. Interpolation interpolation means for calculating interpolation values for θ and stress σ, iron loss calculation means for calculating iron loss in each of the minute areas using the interpolated values, and total of iron loss in each of the minute areas It is characterized by comprising an iron loss summing means for obtaining Further, another feature of the present invention is the iron loss evaluation system for electromagnetic field analysis described above, wherein the magnetic flux density vector determination means determines the residual stress generated in the processing of the steel sheet by stress σ based on the structural analysis. It is characterized in that it is provided with a stress calculating means which is calculated by Another feature of the present invention is the iron loss evaluation system for electromagnetic field analysis described above, wherein the stress σ obtained by the stress calculation means of the magnetic flux density vector determination means is σ = √ (σ _c ² + σ _t ² + σ _s ² ) σ _c : compressive stress, σ _t : tensile stress, σ _s : shear stress.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The iron loss evaluation system for electromagnetic field analysis of the present invention will be described in detail below with reference to the drawings. The iron and steel material has anisotropy in magnetic permeability in a predetermined direction of the steel material, for example, a rolling direction and a direction perpendicular to the rolling direction, and further, anisotropy is caused by mechanical processing such as caulking and welding.

By taking into consideration the anisotropy of magnetic permeability of such a steel material, it becomes possible to evaluate the iron loss with high accuracy. In this case, assuming that the entire target area of the steel material is divided into a plurality of minute regions, the magnetic permeability satisfies the isotropic property inside each minute region, and the value of the angle θ is constant, There is no problem in calculation even if there is a difference in the magnetic permeability μ and the magnetic resistivity ν between the minute regions and the angle θ between the predetermined direction, for example, the rolling direction and the direction of the magnetic flux density B. Given the permeability and the angle θ in this way, a computer can be used to find the solution of the Maxwell equation.

FIG. 1 is an explanatory view showing a pattern in which the entire target area of a steel material is divided into a plurality of grid-like minute areas. In FIG. 1, steel materials are 1, 2, 3 ..., i, i
It is divided into minute regions of +1, i + 2, ..., J, j + 1, j + 2 ,. For example, the magnetic flux density of the i-th small area are △ B _i, the iron loss is assumed to be [Delta] w _i.

In FIG. 1, it is assumed that the magnetic permeability μ and the magnetic resistivity ν are isotropic and have constant values and the magnetic flux density is constant inside each of the divided minute regions. In this way, in the finite element method, it can be considered that even if the boundaries between the minute regions are discontinuous, they have uniform parameters within the regions.

Therefore, also in the calculation of the iron loss of a steel material having anisotropy or non-linearity, the total loss can be easily calculated by obtaining the total sum of the iron loss of each minute region calculated in advance. it can. In Fig. 1, the overall iron loss W
(Watts / kg or watts / m ³ ) is

[0029]

[Equation 6]

Is given by Here, w _i is the iron loss in the minute region. Also, △ direction θ and magnitude .DELTA.B _i of B _i is
It takes a different value for each micro area. Iron loss W
Has a larger value as the magnetic flux density B is larger, but is not necessarily in a linear relationship. The region division is performed on the assumption that the finite element method is applied, but it goes without saying that it can be applied to the difference method or other similar purpose calculation method.

FIG. 2 is an explanatory diagram showing the anisotropy of the magnetic flux density. In FIG. 2, RD is the rolling direction of the steel sheet (rolled d
irection), TD is the direction perpendicular to it (transversal di
rection). When the angle between the direction of the magnetic flux density B and the rolling direction RD of the steel sheet is θ, the H-B curve and the W-B curve
The θ dependence of the curve is given in a shape as shown in FIGS. 3 (a) and 3 (b), for example.

Here, instead of the rolling direction of the steel sheet, an arbitrary
It is also possible to set it in a predetermined direction. Figure 3
Both (a) and (b) show the dependence of the angle θ.
However, the multi-leaf data has a further dependence on the stress σ.
Also shows. The stress σ is the compressive stress (σ_c), Tension
Force (σ_t), And shear stress (σ_s) Caused by.
These stresses are vector quantities, but facilitate numerical calculations
Scalar amount σ ₀As the following equation (Equation 7)
Express.

[0033]

[Equation 7]

In the H-B curve and the W-B curve stored in the database, the scalar amount σ ₀ is used as a parameter in order to facilitate the numerical handling, but the practical error can be sufficiently ignored.

In FIG. 3, θ = 0 °, 15 °, 30 ° ...
Data is given as an H-B function and a WB function, but the data is not given as a function at other angles θ. In this case, the relationship between the magnetic flux density and the magnetic field that needs to be obtained at θ = 20 ° is θ = 15 ° and θ =
The approximate function obtained from the data at 30 ° is repeatedly calculated from the Taylor expansion by the Newton-Raphson method by coupling with the Maxwell equation. On the other hand, the iron loss when the magnetic flux density is given is θ =
It is obtained by interpolation interpolation from the data at 15 degrees and θ = 30 degrees.

If the change in the stress σ is sufficiently small to be ignored, the stress σ may be assumed to be constant. If the stress σ changes sufficiently, the H-B curve and WB corresponding to the respective stress σ
Select the curve and repeat the calculation.

Next, the dependence on the stress σ included in FIGS. 3A and 3B will be described in some detail. As for the stress σ, a positive value indicates tension and a negative value indicates compression. For example, in FIGS. 3A and 3B, +20 MPa>σ> −50
Data in the range of MPa (MPa: megapascal) is dealt with and shown as data for the sampled stress σ values.

Therefore, the magnetic flux density and the iron loss with respect to the stress values not given in the data table can be obtained by the interpolation from the Taylor expansion by the Newton-Raphson method as in the case of the angle θ. That is, (B _i , θ _I ,
σ) determines the iron loss w _i in the small area i.

For example, σ = + 20MP shown in FIG.
In the data of a, the curve of θ = 15 ° and 30 °, and B = 2.0wb / m ² and 3.0wb / m ² were cut, and the point AB
Assuming a region surrounded by CD, point P (θ = 20
The iron loss at B, 2.5 wb / m ² ) shall be obtained.

First, a series expansion is performed from the curves of θ = 15 ° and 30 ° by interpolation approximation to obtain a WB curve of θ = 20 °. Next, the WB curve of θ = 20 ° is cut by straight lines (curves may be used) of B = 2.0 wb / m ² and 3.0 wb / m ² , and B = 2.5 wb / m by interpolation on the B axis. Determine the point P in ² . The iron loss W can be read from the y coordinate axis of the determined point P.

In the actual process, since the graph of FIG. 3B is stored in the database, it is possible to calculate the iron loss by performing the interpolation calculation by the software process of the computer.

As described with reference to FIG. 3, the HB curve changes due to the influence of the stress σ. For example, a concave iron core is shaped by shearing a steel plate, and is used for a rotating machine or the like. At this time, residual stress exists in the iron core due to shearing, mechanical compression, and extension.

FIG. 4 is an explanatory view showing an example of the influence of stress in the iron core on the magnetic flux density. In FIG. 4, x indicates the rolling direction of the steel sheet, B indicates the tangential direction of the magnetic flux, and θ indicates the angle between the x axis and the magnetic flux density B. When the designated position on the space is determined, the magnetic flux density vector B is given and the value of the stress σ is determined. That is, (H−B) (θ, σ) is obtained at the designated spatial position, and (W−)
B) (θ, σ) is determined. The stress corresponding to the spatial position can be obtained by CAD according to the theory of material mechanics.

FIG. 5 shows the routine of the calculation processing. In FIG. 5, 1 is an area dividing means, 2 is a magnetic flux density vector determining means, 3 is a database of magnetic flux density and iron loss, 4 is interpolation interpolation calculating means, 5 is small area iron loss calculating means, and 6 is iron loss. It is a means of summation. The database 3 is composed of a first database representing an H-B curve and a second database representing a WB curve. The H-B curve is frequency dependent and the magnetoresistivity ν increases with increasing frequency.

Therefore, in the Maxwell equation,
The frequency characteristic of the steel sheet is included by ν. The area dividing means 1 divides the entire target area of the steel material into a plurality of minute areas (i
= 1 to n). If the steel material is a flat plate material having a uniform thickness, the shape of the minute region can be made triangular, and in this case, the calculation by the finite element method can be easily applied.

The stress distribution data based on the stress analysis is input to the magnetic flux density vector determination means 2, while the result of the area division from the area division means 1 and the (H-B curve) data from the database 3 are input. input. In the magnetic flux density vector determination means 2, the Newton-Raphson method is used for each divided region, and the convergence calculation of the magnetic flux density vector is performed from the Taylor expansion by coupling with the Maxwell equation.

That is, based on the input data from the area dividing means 1, the magnetic flux density vector determining means 2 in the minute area a _i , the angle θ between the rolling direction RD of the steel sheet and the direction of the magnetic flux density, and the magnetic flux. The magnitude B of the density is determined and given to the interpolation / interpolation calculation means 4. Here, the rolling direction may be replaced by any predetermined direction.

The database 3 of the magnetic field (H-B curve) and iron loss (W-B curve) with respect to the magnetic flux density stores a table of data divided into a plurality of leaves according to the data representing the value of the stress σ as a parameter. The table of each data stores the H-B curve and the WB curve for the angle θ.

The H-B curve and WB curve stored in the database 3 correspond to the magnetic flux density and the magnetic field, and the magnetic flux density and the iron loss corresponding to the angle θ and the stress σ which are sampled and given, respectively. It is what gives a relationship. These data are pre-measured data and sampled angle θ
And holds in the form of a function of stress σ.

Therefore, the relation between the magnetic flux density B and the loss W with respect to an arbitrary angle θ and stress σ is calculated by interpolating and interpolating by means of the interpolating and interpolating means 4 by using the Newton-Raphson method. Ask. The iron loss data (WB curve) of the steel material is interpolated and interpolated by the database 4
Provided to.

Next, using the data of the WB curve from the database 3, the magnetic flux density B in the minute area a _i and the angle θ obtained by the interpolation / interpolation calculation means 4 are used to calculate the iron loss in the minute area. The iron loss w _i is calculated by the calculation means 5. Therefore, the iron loss summation means 6 obtains the total sum W of the iron loss w _i in the minute area a _i . In this way, the iron loss of the steel material having anisotropy is specifically obtained by numerical calculation.

In FIG. 6, H-B based on actual measurement is performed.
Regarding the curve data, the iron loss calculation routine of steel materials considering anisotropy was shown. The solution of Maxwell's equations executed by this routine is accurately obtained by the theoretical model as follows. That is, when the magnetic vector potential A is used to represent the current density J ₀ , the following (Equation 8) is given.

[0053]

[Equation 8]

When ν is represented by a tensor and expressed by a two-dimensional field equation, (Equation 9) is obtained.

[0055]

[Equation 9]

The function χ corresponding to (Equation 9) is given by the following (Equation 1
0).

[0057]

[Equation 10]

This is represented by the value in element e, and element e
Partially differentiating with the potential of the node ie that constitutes
(∂x / Aie) is obtained. Therefore,

[0059]

[Equation 11]

Is an equation to be solved by the finite element method. Here, nu is the total number of unknown nodes. Therefore, when rewriting to apply the Newton-Raphson method, the following (Equation 12) is obtained.

[0061]

[Equation 12]

If the k-th δA _j obtained by solving the matrix of (Equation 12) is obtained, an approximate solution of the potential at the node i obtained in the (k + 1) -th iteration,

[0063]

[Equation 13]

Is obtained. However,

[0065]

[Equation 14]

Further analysis gives the following (formula 15).

[0067]

[Equation 15]

According to the above analysis, the magnetic resistivity represented by a tensor can be obtained by numerical calculation using an analytical model. An example of a specific calculation routine is shown in the flowchart of FIG.

As shown in FIG. 6, the first step S6
Enter the constant in 1. Next, in step S62, the maximum value Bmax of the magnetic flux density is set. next,
Set time T to 1. (Step S63). Since AC analysis is performed in the present embodiment, one cycle is divided by a certain number of divisions, and the transient analysis is performed. Here, the contents divided into 12 are shown (defined in step S70).

Since the initial value of the magnetic resistivity ν is determined and the calculation is a convergence calculation, the coefficient k is set to 1 (step S64). The initial value of the magnetic resistivity ν may be the one calculated at the previous time.

Next, σA ^k is calculated according to (Equation 15). As a result, A ^{k + 1} is obtained (step S65).
Next, the convergence of σA ^k is determined (step S66), and if it has converged, the magnetic flux density vector B is ^obtained from A ^k according to equation 3 (step S70).

On the other hand, if the result of determination in step S66 is that it has not converged, the coefficient k is incremented by 1 (step S6).
8). The magnetic flux density vector B in that state is obtained in all spatially divided cells according to Equation 3, and a predetermined direction and magnetic flux density vector B in a certain cell are obtained.
The magnetic field vector H of the cell is obtained from the B.H curve according to the direction difference .theta.

The magnetic resistivity ν is obtained from the ratio of the magnetic flux density vector B and the magnetic field vector H. Calculate this for all cells. Then, A ^{k at} this time is determined, and σ
A ^k is ^obtained (step S65).

The above is calculated until σA ^k converges. Thereby, the magnetic flux density vector B at that time is obtained (step S67). When the convergence at a certain time ends, the time is advanced by one (step S71), and the balance calculation is performed to obtain the magnetic flux density vector B at that time.

In this case, the time is divided up to 12 (step S70). Actually, further 2 to 5 cycles are calculated, and the convergence in the cycles is checked. According to FIG. 6, since the magnetic resistivity ν is accurately given as the tensor amount from the numerical solution of the Maxwell equation, the H-B curve can be analyzed accurately.

Although the scale of the database could not be easily increased in the past, in recent years, the size of the database is 1 GB to 50 G.
It has become easy to realize even a size such as B. With such advances in computer peripheral technology, it has become extremely easy to consider the stress σ.

Therefore, the evaluation system shown in FIG. 4 has been evaluated in consideration of the mechanical stress generated inside the steel material during the caulking and welding of the steel material. Furthermore, it has become possible to make a detailed analysis and create a database relating to stress and the like in consideration of the grain size of the crystal structure of a steel material or the like. Therefore, it is within the scope of the evaluation system of the present invention to include the grain size as a factor of the stress σ in the database as an anisotropic parameter.

[0078]

As described above, the present invention divides the entire area of the steel material into minute areas, and an angle formed by a predetermined direction and the magnetic flux density direction with respect to each of the divided minute areas, Material with large anisotropy is obtained by calculating the iron loss data taking into account the stress generated by processing as a parameter from the database and calculating the sum of the iron loss data obtained in each micro area. However, it is possible to obtain the effect that the iron loss can be evaluated and calculated without considering the anisotropy of the magnetic flux density and the nonlinearity of the magnetic flux density with respect to the magnetic field.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a pattern in which a steel material is divided into lattice-shaped minute regions.

FIG. 2 is an explanatory diagram used for explaining anisotropy of magnetic flux density.

FIG. 3 is a graph showing an angle, a dependency, and a stress dependency of an HB curve and a WB curve by giving a dependency on stress in a graph of a plurality of leaves.

FIG. 4 is an explanatory diagram showing an example of the influence of stress in the iron core on the magnetic flux density.

FIG. 5 is a block diagram showing an iron loss calculation routine of a steel material in consideration of anisotropy.

FIG. 6 is an explanatory diagram showing a routine for accurately obtaining a magnetic resistivity using a Maxwell equation as a tensor.

FIG. 7 is an explanatory diagram showing a routine for obtaining an iron loss of a steel material using a Maxwell equation according to a conventional technique.

[Explanation of symbols]

1 Area dividing means 2 Magnetic flux density vector determination means 3 Magnetic flux density and iron loss database 4 Interpolation interpolation calculation means 5 Iron loss calculation means in micro area 6 Iron loss summation means

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Claims (5)

[Claims] 1. An area dividing means for dividing an entire target area of a steel material into a plurality of minute areas, and an anisotropy of an angle θ between a predetermined direction of a steel sheet and a magnetic flux density direction in the minute areas. The data of the magnetic field (H-B curve) with respect to the magnetic flux density is stored as a parameter of, and provided to the determination of the magnetic flux density vector, and the data (H- stored in the first database.
B curve), a magnetic flux density vector determining means for determining the angle θ and the magnitude B of the magnetic flux density on the basis of the Maxwell equation in the minute division region, and the angle θ as an anisotropic parameter. A second database that stores data of iron loss (WB curve) with respect to magnetic flux density and is provided for calculation of iron loss, and iron loss (WB) stored in the second database.
(Curve) as data, and interpolation interpolation means for calculating an interpolated value of the WB curve for an arbitrary angle θ, and iron loss calculation means for calculating the iron loss of each of the minute regions by using the interpolated value. An iron loss evaluation system for electromagnetic field analysis, comprising: an iron loss summing means for calculating the sum of iron losses of the respective minute regions. 2. An area dividing means for dividing an entire target area of a steel material into a plurality of minute areas, and an anisotropy of an angle θ between a predetermined direction of a steel sheet and a direction of magnetic flux density in the minute areas. Data of magnetic field (H-B curve) and iron loss (W-B curve) with respect to magnetic flux density are stored as parameters of, and provided to the calculation of iron loss, and H-B stored in the database. Magnetic flux density vector determining means for determining the angle θ and the magnitude B of the magnetic flux density based on the curve based on the Maxwell equation in the micro area, and the iron loss for the magnetic flux density stored in the database. Interpolation interpolation means for calculating an interpolated value of the WB curve with respect to an arbitrary angle θ using (WB curve) as data, and iron loss of each minute region is calculated using the interpolated value. Loss calculation means and the iron loss evaluation system of an electromagnetic field analysis, characterized by being configured to and a core loss sum means for obtaining a total sum of the iron loss of each minute region. 3. An area dividing means for dividing an entire target area of a steel material into a plurality of minute areas, and an angle θ and a stress σ between a predetermined direction of a steel sheet and a direction of magnetic flux density in the minute areas. Data of the magnetic field (H-B curve) and iron loss (W-B curve) with respect to the magnetic flux density is stored as a parameter of anisotropy, and is stored in the database, which is provided for calculation of iron loss. Based on the H-B curve, the angle θ and the magnitude B of the magnetic flux density are calculated based on the Maxwell's equation and the stress σ in the previous minute region.
And a magnetic flux density vector determining means for determining the magnetic flux density vector, and an interpolating interpolation means for calculating an interpolated value for an arbitrary angle θ and stress σ using the iron loss (WB curve) for the magnetic flux density stored in the database as data. And an iron loss calculating means for calculating the iron loss of each of the minute areas using the interpolated value, and an iron loss summing means for obtaining the sum of the iron loss of each of the minute areas. A characteristic iron loss evaluation system for electromagnetic field analysis. 4. The iron loss evaluation system for electromagnetic field analysis according to claim 3, wherein the magnetic flux density vector determination means obtains residual stress generated in processing of a steel sheet by calculating stress σ based on structural analysis. An iron loss evaluation system for electromagnetic field analysis, characterized by comprising means. 5. The iron loss evaluation system for electromagnetic field analysis according to claim 4, wherein the stress σ obtained by the stress calculation means of the magnetic flux density vector determination means is σ = √ (σ _c ² + σ _t ² + σ _s ² ) σ _c : compressive stress, σ _t : tensile stress, σ _s : shear stress, an iron loss evaluation system for electromagnetic field analysis.