JP2018163053A - Magnetic property analysis system and magnetic property analysis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately derive hysteresis loss and eddy current loss of a magnetic material even when the density of a magnetic flux generated in the magnetic material is not a sine wave.SOLUTION: A waveform correction part 613 performs correcting an indication waveform of an excitation voltage according to the difference between a measured waveform and a target waveform of an induction voltage until the measured waveform of the induction voltage is converged to the target waveform. A convergence determination part 614 determines that the measured waveform of the induction voltage is converged to the target waveform when a value using an integrated value for one cycle of the absolute value of difference values at the time instances between the measured waveform and target waveform of the induction voltage is equal to or less than a reference value. An analysis part 116 obtains a magnetic flux density vector and an eddy current vector generated in a measurement sample S by applying, to an excitation coil 102, the indication waveform of the excitation voltage when the measured waveform of the induction voltage is converged to the target waveform, by executing three-dimensional numerical analysis based on Maxwell's equations.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a magnetic property analysis system and a magnetic property analysis method, and is particularly suitable for use in analyzing magnetic properties of a magnetic material.

  Measuring magnetic properties (for example, magnetic flux density, magnetic field strength, and iron loss) of magnetic materials for the purpose of designing magnetic materials such as electromagnetic steel sheets used for iron cores (cores) of electrical equipment. It has been broken. Non-Patent Documents 1 and 2 describe that the magnetic properties of a test piece are measured under the condition that the waveform of magnetic flux density generated in the test piece made of an electromagnetic steel sheet is close to a sine wave.

  However, the waveform of the magnetic flux density generated in the magnetic material of an actual electric device is a waveform including a harmonic component and does not become a sine wave. For example, in a motor driven by an inverter, the waveform of the magnetic flux density generated in the core due to the shape of the core (stator core and rotor core) used in the motor, the number of poles of the motor, the drive conditions of the inverter, etc. , It becomes a complex waveform containing harmonic components.

  Therefore, even if the target magnetic flux density is other than a sine wave, there is a technique described in Patent Document 1 as a technique for exciting a magnetic material under conditions close to the target magnetic flux density. In Patent Document 1, the magnetic flux density of a magnetic material is measured, and the magnetic field strength corresponding to the measured magnetic material magnetic flux density is derived. Then, a value obtained by multiplying the ratio of the error between the derived magnetic field strength and the target magnetic field strength by the target excitation voltage is set as a correction amount of the excitation voltage. Further, it is determined whether or not the magnetic flux density of the magnetic material has converged based on the result of comparing the magnetic flux density of the magnetic material with the target magnetic flux density. If the magnetic flux density of the magnetic material has not converged as a result of this determination, the magnetic material is excited with the target excitation voltage updated using the correction amount. Such an operation is repeated until the magnetic flux density of the magnetic material converges.

Japanese Patent Laid-Open No. 2006-114387

JIS C 2550-1: 2011 "Electromagnetic steel strip test method Part 1 Method for measuring magnetic properties of electromagnetic steel strip with Epstein tester" JIS C 2556: 2015 “Measuring method of magnetic properties of electromagnetic steel strip using single plate tester” Takayoshi Nakata, Norio Takahashi, “Fine Element Method of Electrical Engineering 2nd Edition”, Morikita Publishing Co., Ltd., April 1986 Junji Kitao, 6 others, “Study on application of play model to hysteresis magnetic field analysis”, Electrotechnical Institute of Static and Rotating Machine Joint Research Materials, SA-12-16, RM-12-16, p. 89-p. 94, 2012 JIS C 2552: 2014 “Non-oriented electrical steel strip”

  However, the technique described in Patent Document 1 cannot determine the ratio of hysteresis loss and eddy current loss as a breakdown of iron loss. Also, it is determined that the magnetic flux density of the magnetic material has converged when the arithmetic average value of the error rate using the absolute value of the difference between the magnetic flux density and the target magnetic flux density is less than or equal to the threshold value at all sampling timings over one cycle. To do. In this case, since the absolute value of the difference between the magnetic flux density and the target magnetic flux density is averaged, depending on the waveform shape of the target magnetic flux density, it is not easy to bring the magnetic flux density close to the target magnetic flux density with high accuracy. For this reason, when the magnetic flux density which generate | occur | produces in a magnetic material is not a sine wave, there exists a possibility that the breakdown (hysteresis loss and eddy current loss) of the iron loss of the said magnetic material cannot be derived | led-out accurately.

  The present invention has been made in view of the above-described problems, and even when the magnetic flux density generated in a magnetic material is not a sine wave, the hysteresis loss and eddy current loss of the magnetic material can be derived with high accuracy. The purpose is to be able to.

  The magnetic characteristic analysis system of the present invention includes an application means for applying an excitation voltage to an excitation coil for exciting a measurement sample made of a magnetic material, and induction induced in the first coil by exciting the measurement sample. Detection means for detecting a voltage; acquisition means for acquiring a target waveform of the induced voltage; determination means for determining whether or not the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage; and the determination means If it is determined that the measured waveform of the induced voltage has not converged to the target waveform of the induced voltage, the excitation voltage is determined based on the difference between the measured waveform of the induced voltage and the target waveform of the induced voltage. And when the measurement sample is excited with the excitation voltage corrected by the correction means when the measurement waveform of the induced voltage converges to the target waveform of the induced voltage Analyzing means for deriving a numerical solution of magnetic flux density vector and eddy current vector in a three-dimensional space of the measurement sample and deriving information for identifying hysteresis loss and eddy current loss in the measurement sample based on the derived numerical solution When the excitation voltage is corrected by the correction unit, the application unit applies the corrected excitation voltage to the excitation coil, and the determination unit measures the induced voltage measurement waveform. Until the excitation voltage is determined to have converged to the target waveform of the induced voltage, the correction of the excitation voltage by the correction means, the application of the excitation voltage by the application means, and the detection of the induced voltage by the detection means. Repeatedly, the determination means calculates the absolute value of the difference between the measured waveform of the induced voltage and the target waveform of the induced voltage at mutually corresponding times. Based on the integrated value of the period, or the amplitude difference in each of a plurality of frequency components of the measured waveform of the induced voltage and the target waveform of the induced voltage, the measured waveform of the induced voltage becomes the target of the induced voltage. It is characterized by determining whether or not the waveform has converged.

  The magnetic characteristic analysis method of the present invention includes an application step of applying an excitation voltage to an excitation coil for exciting a measurement sample made of a magnetic material, and induction induced in the first coil by exciting the measurement sample. A detection step of detecting a voltage; an acquisition step of acquiring a target waveform of the induced voltage; a determination step of determining whether or not the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage; and the determination step If it is determined that the measured waveform of the induced voltage has not converged to the target waveform of the induced voltage, the excitation voltage is determined based on the difference between the measured waveform of the induced voltage and the target waveform of the induced voltage. And a step of exciting the measurement sample with the excitation voltage corrected by the correction step when the measurement waveform of the induced voltage converges to the target waveform of the induced voltage. An analysis process for deriving numerical solutions of magnetic flux density vectors and eddy current vectors in a three-dimensional space of the measurement sample, and deriving information for identifying hysteresis loss and eddy current loss in the measurement sample based on the derived numerical solutions; In the application step, when the excitation voltage is corrected by the correction step, the corrected excitation voltage is applied to the excitation coil, and the measurement waveform of the induced voltage is determined by the determination step. The excitation voltage is corrected by the correction step, the excitation voltage is applied by the application step, and the induced voltage is detected by the detection step until it is determined that the induced voltage has converged to the target waveform. The determination step includes one cycle of the absolute value of the difference between the measurement waveform of the induced voltage and the target waveform of the induced voltage at mutually corresponding times. Or the measured waveform of the induced voltage becomes the target waveform of the induced voltage based on the difference in amplitude of each of the plurality of frequency components of the measured waveform of the induced voltage and the target waveform of the induced voltage. It is characterized by determining whether it has converged.

  According to the present invention, the hysteresis loss and eddy current loss of the magnetic material when the magnetic flux density generated in the magnetic material is not a sine wave can be derived with high accuracy.

It is a figure which shows the 1st example of a structure of a magnetic characteristic analysis system. It is a flowchart explaining the 1st example of a structure of the magnetic characteristic analysis method. It is a figure which shows an example of the waveform of the output voltage of a PWM inverter. It is a figure which shows an example of the waveform of magnetic flux density. It is a figure which shows an example of the result of having compared the iron loss at the time of operating a PWM inverter with a different modulation factor. It is a figure which shows the 2nd example of a structure of a magnetic characteristic analysis system. It is a flowchart explaining the 2nd example of a structure of a magnetic characteristic analysis method. It is a figure which shows an example of a structure of an IPM motor. It is a figure which shows an example of the measurement waveform of an induced voltage, and a target waveform in the example of an invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, the first embodiment will be described.
FIG. 1 is a diagram illustrating an example of a configuration of a magnetic characteristic analysis system. FIG. 2 is a flowchart for explaining an example of a magnetic property analysis method using the magnetic property analysis system. In the magnetic characteristic analysis system of this embodiment, a magnetic flux density generated in a predetermined region (position) of the core is generated in the measurement sample S when a predetermined excitation voltage is applied to the excitation winding for exciting the core of the electrical device. The measurement sample S is excited as described above. The magnetic material used as the measurement sample S and the magnetic material used for the core of the electric device are the same type of magnetic material. In other words, it is manufactured from the raw materials of the same component through the same manufacturing process, except for inevitably occurring variations in the manufacturing process. The difference between the two depends on the measurement system or whether it is molded into the core shape of the electrical equipment. It is only molded into a different shape. Therefore, both have the same magnetic characteristics. In particular, when the magnetic material used for the core of the electric device is plate-shaped, the thickness of the magnetic material used as the measurement sample S and the thickness of the magnetic material used for the core of the electric device are the same.

  In addition, as long as the electrical equipment is an electrical equipment whose core is excited during operation, such as a rotating electrical machine represented by a motor, a transformer, a current transformer, a transformer, a reactor, etc. It may be a simple electrical device. In the present embodiment, a case where the magnetic material is an electromagnetic steel plate will be described as an example. However, the magnetic material may be any magnetic material used as a core, such as a soft magnetic material typified by an electromagnetic steel plate.

In this embodiment, the target waveform of magnetic flux density (target waveform (relationship between magnetic flux density and time)) is compared with the measured waveform (measured waveform), and the measurement sample is adjusted so that the measured waveform matches the target waveform. Excites S.
The shape of the measurement sample S is assumed to be a simpler shape than the magnetic material constituting the core of the electric device. For example, a test piece set in the Epstein tester described in Non-Patent Document 1, a test piece set in a single plate tester described in Non-Patent Document 2, or a ring-shaped sample is used as the measurement sample S. Can do.

In FIG. 1, the magnetic characteristic analysis system includes an excitation power source 101, an excitation coil 102, a search coil 103, a voltmeter 104, and an arithmetic device 110.
The excitation power supply 101 applies an excitation voltage to the excitation coil 102. The waveform of the excitation voltage is a waveform that periodically repeats the waveform for one cycle determined by the waveform correction unit 114 in the arithmetic unit 110 described later. An exciting current flows through the exciting coil 102 by this exciting voltage. The excitation power source 101 is configured using, for example, an arbitrary waveform generator and a power amplifier.

  The excitation coil 102 is a coil for exciting the measurement sample S, and the excitation coil 102 is wound around the measurement sample S. When the measurement sample S is a single plate, the excitation coil 102 may be wound around a yoke that is magnetically coupled to the measurement sample S.

  The search coil 103 is a so-called B coil, and is a coil for detecting an induced voltage induced when the measurement sample S is excited. The search coil 103 is wound around the measurement sample S. That is, the search coil 103 is wound so as to surround a magnetic flux generated when the measurement sample S is excited.

The voltmeter 104 measures the voltage (induced voltage) across the search coil 103.
The arithmetic device 110 acquires the induced voltage measured by the voltmeter 104 as time series data based on a predetermined sampling period. Further, the arithmetic unit 110 generates an excitation voltage waveform and instructs the excitation power source 101 to derive the magnetic characteristics (information specifying the hysteresis loss and eddy current loss) of the measurement sample S.

(Configuration of Arithmetic Device 110 and Magnetic Characteristic Analysis Method)
Below, an example of the function which the arithmetic unit 110 has will be described. The hardware of the arithmetic device 110 is realized by using, for example, an information processing device including a CPU, ROM, RAM, HDD, and various interfaces, and dedicated hardware.

<Target waveform acquisition unit 111, S201>
The target waveform acquisition unit 111 acquires a target waveform for one cycle as a target waveform of the induced voltage (a target value of the induced voltage at each time). Furthermore, the target waveform acquisition unit 111 acquires a target waveform for one cycle as a target waveform of the magnetic flux density (a target value at each time of the magnetic flux density). The following two methods will be described as an example of a method for obtaining target waveforms of induced voltage and magnetic flux density.

First, the first method will be described.
A search coil is wound around a predetermined region (region where magnetic properties are to be analyzed) of the core of the electrical device whose magnetic properties are to be analyzed. Then, an induced voltage (voltage across the search coil) induced in the search coil is measured by applying a predetermined excitation voltage to the excitation winding that excites the core of the electric device. It should be noted that the region around which the search coil is wound does not need to exactly match the region where the magnetic characteristics are to be analyzed. This is because, for example, the search coil may not be wound around a region that exactly matches a region where magnetic characteristics are desired to be analyzed due to the structure of the electric device. In this case, the search coil is wound around a region as close as possible to a region where magnetic characteristics are to be analyzed.

Here, the induced voltage is V (t) [V]. The number of turns of the search coil is N [times]. Let the magnetic flux be φ (t) [wb]. The magnetic flux density is B (t) [T]. Let S [m ² ] be the cross-sectional area of the electrical steel sheet in the search coil. Then, the following expressions (1) and (2) are established.
V (t) = − N × dφ (t) / dt (1)
φ (t) = B (t) × S (2)

Here, the number of turns and the area of the search coil 103 for the measurement sample S and the search coil for the electric device are different (in many cases). Therefore, according to this difference, it is necessary to convert the value of the induced voltage induced in the search coil for the electric device at each time into the value of the induced voltage induced in the search coil 103 for the measurement sample S at each time. . Specifically, the number of turns of the search coil 103 with respect to the measurement sample S and the cross-sectional area of the electromagnetic steel plate in the search coil 103 are N _A and S _A , respectively. The number of turns of the search coil for the electric device and the cross-sectional area of the electromagnetic steel sheet in the search coil are N _M and S _M , respectively. V _M (t) is an induced voltage induced in the search coil for the electric device. Then, the target waveform V _A (t) of the induced voltage is calculated by the following equation (3).
V _A (t) = {(N _A × S _A ) ÷ (N _M × S _M )} × V _M (t) (3)
The cross-sectional area of the electromagnetic steel sheet is a cross section obtained by cutting the electromagnetic steel sheet in a direction perpendicular to the axial direction of the search coil (the direction of the magnetic path due to the magnetic flux generated in the measurement sample S when the measurement sample S is excited). It is an area.

Further, the induced voltage induced in the search coil for the electric device is V (t), the number of turns of the search coil for the electric device is N, and the cross-sectional area of the electrical steel sheet in the search coil for the electric device is S (1 ) And (2), the target waveform B (t) of the magnetic flux density in a predetermined region of the core of the electric device is obtained for one period, and is set as the target waveform of the magnetic flux density.
The cross-sectional area of the electromagnetic steel sheet is a cross section obtained by cutting the electromagnetic steel sheet in a direction perpendicular to the axial direction of the search coil (the direction of the magnetic path due to the magnetic flux generated in the measurement sample S when the measurement sample S is excited). It is an area.

  Here, in order to reduce noise at the time of measurement, it is preferable to perform calculation according to equation (3) after removing higher-order harmonic components contained in the induced voltage calculated as described above. For example, fast Fourier transform is performed on the waveform of the induced voltage calculated as described above, and, for example, the spectrum of the harmonic component of the 20th order or higher is removed, and then inverse Fourier transform is performed. As a result, higher-order harmonic components included in the target waveform of the induced voltage can be removed. Further, calculation of the equations (1) and (2) may be performed after removing higher-order harmonic components contained in the target waveform of the magnetic flux density.

  For example, the target waveform acquisition unit 111 receives the target waveform of the induced voltage and the magnetic flux density from the external calculation device that calculates the target waveform of the induced voltage and the magnetic flux density in this way, thereby obtaining the induced voltage and the magnetic flux density. A target waveform can be acquired. In addition, the target waveform acquisition unit 111 receives the induced voltage induced in the search coil for the electric equipment, and calculates the target waveform of the induced voltage and the magnetic flux density, thereby acquiring the target waveform of the induced voltage and the magnetic flux density. You can also. In addition, the target waveform acquisition unit 111 reads the target waveform data of the induced voltage and the magnetic flux density by reading the target waveform data of the induced voltage and the magnetic flux density from the storage medium that stores the data of the target waveform of the induced voltage and the magnetic flux density. You can also get

Next, the second method will be described.
Two-dimensional numerical analysis based on Maxwell's equations for the magnetic flux density vector generated in a predetermined region of the core by applying a predetermined excitation voltage to the excitation winding that excites the core of the electrical device whose magnetic characteristics are to be analyzed ( It is obtained by performing a numerical analysis (that is, a numerical analysis in a two-dimensional space) on a plane in a direction parallel to the plate surface of the electrical steel sheet constituting the core. In addition, the magnetic flux density vector calculated | required in this way has a component of the plate | board surface direction of the magnetic steel plate which comprises a core, and does not have a component of a plate | board thickness direction. Numerical analysis is performed by a computer.

  As the numerical analysis, for example, a finite element method can be used. For example, the shape of a magnetic steel sheet, the size of a minute region (so-called mesh), data of a BH curve (curve representing the relationship between the magnetic flux density B and the magnetic field strength H), and excitation conditions (for example, excitation voltage at each time) Is used as a parameter of a physical quantity for obtaining a solution of numerical analysis. That is, taking these parameters into consideration, a magnetic flux density vector can be obtained for each minute region as a numerical solution of Maxwell's equations.

The basic equations for calculating the magnetic flux density vector B and the eddy current vector J _e are generally given by the following equations (4) to (7).

In the equations (4) to (7), μ is a magnetic permeability [H / m], A is a vector potential [T · m], σ is a conductivity [S / m], J ₀ is the excitation current density [A / m ² ], and φ is the scalar potential [V].
After solving the equations (4) and (5) simultaneously to obtain the vector potential A and the scalar potential φ, the magnetic flux density vector B and the eddy current vector J _e are obtained from the equations (6) and (7). Calculated.
Note that the method for obtaining the magnetic flux density vector and the eddy current vector in this way can be realized by a known technique as described in Non-Patent Document 3, and therefore detailed description thereof is omitted here. .
Then, from the magnetic flux density vector for one cycle in a predetermined region of the core of the electrical device obtained as described above, a waveform for one cycle of the induced voltage is obtained based on the equations (1) and (2). The obtained waveform is set as a target waveform of the induced voltage.

  Here, in order to reduce errors at the time of numerical analysis such as rounding error, the (formal) induced voltage is obtained by removing higher-order harmonic components included in the target waveform of the induced voltage calculated as described above. A target waveform is preferable. For example, the fast Fourier transform is performed on the target waveform of the induced voltage calculated as described above, and the inverse Fourier transform is performed after removing, for example, the spectrum of the higher-order harmonic component. By doing so, it is possible to remove higher-order harmonic components contained in the target waveform of the induced voltage calculated as described above. Furthermore, a (formal) magnetic flux density target waveform may be obtained by removing higher-order harmonic components contained in the magnetic flux density target waveform.

  The target waveform acquisition unit 111 can acquire the target waveform of the induced voltage and the magnetic flux density by calculating the target waveform of the induced voltage and the magnetic flux density as described above. In addition, the target waveform acquisition unit 111 receives induced voltage and magnetic flux density target waveform data transmitted from an external computing device that calculates the induced voltage and magnetic flux density target waveform in the same manner as described above. Thus, the target waveforms of the induced voltage and the magnetic flux density can be acquired. In addition, the target waveform acquisition unit 111 reads the target waveform data of the induced voltage and the magnetic flux density by reading the target waveform data of the induced voltage and the magnetic flux density from the storage medium that stores the data of the target waveform of the induced voltage and the magnetic flux density. It can also be acquired.

<Target waveform storage unit 112, S202>
The target waveform storage unit 112 stores the target waveform of the induced voltage and magnetic flux density acquired by the target waveform acquisition unit 111.

<Magnetic flux density deriving unit 113, S203>
The magnetic flux density deriving unit 113 assumes that the induced voltage measured by the voltmeter 104 is V (t), the number of turns of the search coil 103 is N, and the cross-sectional area of the electrical steel sheet in the search coil 103 is S (1) The measurement waveform (B (t) for one cycle) of the magnetic flux density in the measurement sample S is derived by performing the calculation based on the equation and the equation (2) for one cycle.

  The magnetic flux density deriving unit 113 removes high-order harmonic components included in the measurement waveform of the magnetic flux density calculated as described above in order to reduce noise during measurement. A measurement waveform is preferable. For example, the fast Fourier transform is performed on the measurement waveform of the magnetic flux density calculated as described above, and the inverse Fourier transform is performed, for example, after removing the spectrum of the harmonic component of the 20th order or higher. By doing so, higher-order harmonic components included in the measurement waveform of the magnetic flux density calculated as described above can be removed.

<Waveform correction unit 114, S204>
The waveform correcting unit 114 removes higher-order harmonic components included in the measurement waveform of the induced voltage measured by the voltmeter 104. For example, fast Fourier transform is performed on the measurement waveform of the induced voltage, and for example, the spectrum of the harmonic component of 20th order or higher is removed, and then the inverse Fourier transform is performed. Thereby, higher-order harmonic components included in the induced voltage induced in the search coil 103 with respect to the measurement sample S can be removed. Next, the waveform correcting unit 413 calculates a value at a certain time of the measured waveform of the induced voltage from which the harmonic component is removed at a time corresponding to the time of the target waveform of the induced voltage stored in the target waveform storage unit 112. A value subtracted from the value is obtained at each time in one cycle (hereinafter, the value thus obtained is referred to as a difference). Then, the waveform correcting unit 114 adds the value obtained by multiplying the difference obtained for a certain time by the relaxation coefficient to the value of the time corresponding to the current time of the waveform of the current excitation voltage. The waveform correcting unit 114 performs such correction by addition at each time in one cycle. The relaxation coefficient is for suppressing hunting of the excitation voltage, and has a value greater than 0 (zero) and less than 1. For example, a value of 0.2 to 0.3 can be adopted as the relaxation coefficient. Alternatively, the relaxation coefficient may be 1, and the difference may be added as it is to the current excitation voltage waveform. Here, by removing the harmonic component from the measurement waveform of the induced voltage in advance, it is possible to suppress the hunting of the indication waveform of the excitation voltage that cannot be suppressed even if the relaxation coefficient is used.

  At the start of measurement, there is no measurement waveform of induced voltage. Therefore, the waveform correction unit 114 employs the target waveform of the induced voltage stored in the target waveform storage unit 112 as the initial value of the instruction waveform of the excitation voltage. In this way, from the beginning of measurement, the excitation voltage having the same waveform as the target waveform is output from the excitation power supply 101, and the time until the convergence determination unit 115, which will be described later, determines that the magnetic flux density has converged. Is preferable because it accelerates. However, the initial value of the instruction waveform of the excitation voltage is not limited to the target waveform of the induced voltage, and may be an arbitrary waveform.

<Convergence determination unit 115, S203 to S205>
The convergence determination unit 115 determines whether or not the measured magnetic flux density waveform derived by the magnetic flux density deriving unit 113 has converged to the target magnetic flux density waveform stored in the target waveform storage unit 112. In the present embodiment, the convergence determination unit 115 uses the integrated value for one cycle of the absolute value of the difference between the target waveform of the magnetic flux density and the measured waveform at the time corresponding to each other. It is determined whether or not the waveform has converged. Specifically, the target waveform of the magnetic flux density and B _A (t), the measured waveform of the magnetic flux density and B _P (t), the start of one period, t _s end times, respectively, when t _e, convergence The determination unit 115 determines that the measurement waveform of the magnetic flux density has converged to the target waveform when the following expression (8) is satisfied, and determines that the measurement waveform of the magnetic flux density has not converged to the target waveform otherwise. To do. The convergence determination unit 115 may use the following equation (9) instead of the equation (8).

  Equation (8) is an example in the case where the integrated value for one cycle of the absolute value of the difference at the time corresponding to the target waveform and the measurement waveform of the magnetic flux density is used as it is. Equation (9) is an integrated value for one cycle of the absolute value of the difference between the target waveform of the magnetic flux density and the measured waveform at the time corresponding to each other. It is an example at the time of expressing as a ratio with respect to the integrated value.

  When the convergence determining unit 115 determines that the measured magnetic flux density waveform has not converged to the target waveform, the waveform correcting unit 114 corrects the above-described excitation voltage instruction waveform. That is, the waveform correction unit 114 repeatedly corrects the excitation voltage instruction waveform described above until the convergence determination unit 115 determines that the measured magnetic flux density waveform has converged to the target waveform.

<Analysis unit 116, S206>
The analysis unit 116 applies the (latest) excitation voltage instruction waveform corrected by the waveform correction unit 114 to the excitation coil 102 when the measurement waveform of the magnetic flux density converges to the target waveform. The generated magnetic flux density vector and eddy current vector are obtained by executing a three-dimensional numerical analysis based on Maxwell's equations (ie, a numerical analysis of magnetic flux density in a three-dimensional space). Note that the magnetic flux density vector and the eddy current vector obtained in this way have a component in the plate surface direction and a component in the plate thickness direction of the electromagnetic steel plate constituting the core. As described above, the numerical analysis is performed by a computer. As the numerical analysis, for example, a finite element method can be used.

For example, the analysis unit 116 derives the magnetic hysteresis characteristic in the minute region from the magnetic flux density vector B in a certain minute region and the waveform in one cycle of the magnetic field vector H corresponding to the magnetic flux density vector B. Then, the analysis unit 116 calculates, for example, the following equation (10), and calculates the area of the derived magnetic hysteresis characteristic as the hysteresis loss w _ha in the minute region. Further, the analysis unit 116 performs, for example, the calculation of the following equation (11) based on the eddy current vector J _e in a certain minute region, the volume of the minute region, and the electrical conductivity σ of the electromagnetic steel sheet, The eddy current loss _we0 in the minute region is derived. In the equation (11), T is the period of the eddy current vector J _e . The analysis unit 116 performs the above calculation for all the minute regions.

Then, the analysis unit 116 derives the sum of the hysteresis losses w _ha in all the minute regions as the hysteresis loss of the measurement sample S. Further, the analysis unit 116 derives the sum of the eddy current loss _we0 in all the minute regions as the eddy current loss of the measurement sample S. Further, the analysis unit 116 derives the sum of the hysteresis loss w _ha and the eddy current loss _{we0 in} the same minute region as the iron loss w of the minute region for all the minute regions, and iron in all the minute regions. The total sum of the losses w is derived as the iron loss of the measurement sample S. In the following description, the hysteresis loss, eddy current loss, and iron loss of the measurement sample S are referred to as magnetic characteristics of the measurement sample S as necessary.

  Note that a technique for calculating hysteresis loss and eddy current loss by three-dimensional numerical analysis can be realized by a known technique as described in Non-Patent Document 4, and therefore, a detailed description thereof will be given here. Is omitted. In addition, since the iron loss is expressed by the sum of hysteresis loss and eddy current loss, the analysis unit 116 uses only two of the iron loss, hysteresis loss, and eddy current loss as the magnetic characteristics of the measurement sample S. May be derived as The analysis unit 116 may derive the iron loss and the ratio of the hysteresis loss or the eddy current loss to the iron loss as the magnetic characteristics of the measurement sample S.

<Output unit 117, S207>
The output unit 117 outputs information on the magnetic characteristics of the measurement sample S derived by the analysis unit 116. As an output form, for example, at least one of display on a computer display, transmission to an external device, and storage in a storage medium outside or inside the arithmetic device 110 can be employed.
(Summary)
As described above, in this embodiment, the waveform of the induced voltage detected in a predetermined region of the core when the core of the electrical device is excited under a predetermined excitation condition is set as a target waveform of the induced voltage, The waveform of the magnetic flux density is set as the target waveform of the magnetic flux density. The waveform correction unit 114 corrects the instruction waveform of the excitation voltage according to the difference between the measurement waveform of the induced voltage and the target waveform in the measurement sample S, and the convergence determination unit 115 converges the measurement waveform of the magnetic flux density to the target waveform. Repeat until it is determined. The convergence determination unit 115 measures the magnetic flux density when the absolute value of the difference between the measured values of the magnetic flux density and the target waveform at each time is equal to or less than a reference value using an integrated value for one period. It is determined that the waveform has converged to the target waveform. Then, the analysis unit 116 applies the indication waveform of the excitation voltage corrected by the waveform correction unit 114 to the excitation coil 102 when the measurement waveform of the magnetic flux density converges to the target waveform, thereby generating the magnetic flux density generated in the measurement sample S. Vectors and eddy current vectors are determined by performing a three-dimensional numerical analysis based on Maxwell's equations. In this way, when determining whether or not the measurement waveform of the magnetic flux density has converged to the target waveform, the averaged value is not used, so even if the harmonic waveform is included in the target waveform of the magnetic flux density, the magnetic flux density Can be converged to the target waveform with high accuracy. Therefore, even when the magnetic flux density in the local region of the core of the electric device is not a sine wave, the hysteresis loss and eddy current loss in the region can be derived with high accuracy. In addition, since the three-dimensional numerical analysis is performed on the measurement sample S, the calculation load can be reduced as compared with the case where the three-dimensional numerical analysis is performed on the electrical equipment. Therefore, the magnetic characteristics (hysteresis loss and eddy current loss) in the local region of the core of the electric device can be derived within a realistic time.

(Modification)
In the present embodiment, the convergence determination unit 115 uses the integrated value for one cycle of the absolute value of the difference between the time corresponding to the target waveform and the measurement waveform of the magnetic flux density to generate the target waveform of the magnetic flux density. It is determined whether or not it has converged. However, this is not always necessary. The convergence determination unit 115 uses the result of obtaining the difference (absolute value) of the amplitude of the same frequency component of the target waveform and the measurement waveform of the magnetic flux density for each of the plurality of frequency components, and the target waveform of the magnetic flux density is the target. It may be determined whether or not the waveform has converged. For example, the convergence determination unit 115 performs fast Fourier transform on each of the target waveform and the measurement waveform of the magnetic flux density, and obtains a spectrum (amplitude) for each of a plurality of frequency components. And the convergence determination part 115 calculates | requires the absolute value of the difference of the spectrum of the same frequency component about each of several frequency component. As the plurality of frequency components, a frequency component of the fundamental wave and a frequency component corresponding to the 2nd to nth harmonics (n is an integer of 3 or more) can be employed. Then, the convergence determination unit 115 determines whether or not the absolute value of the spectrum difference of a certain frequency component is equal to or less than a reference value set in advance for the frequency component. Do for each. Then, the convergence determination unit 115 sets the measurement waveform of the magnetic flux density as the target waveform when the absolute value of the spectrum difference is equal to or less than a reference value set in advance for the frequency component for all of the plurality of frequency components. Otherwise, it is determined that the measured magnetic flux density waveform has not converged to the target waveform.
Moreover, each part of the arithmetic unit 110 may be composed of a plurality of devices.

[Second Embodiment]
Prior to describing the second embodiment of the present invention, the knowledge obtained by the present inventors will be described.
FIG. 3 is a diagram illustrating an example of a waveform (relationship between voltage and time) of an output voltage of a PWM (Pulse Width Modulation) inverter. In FIG. 3, a voltage 301 is an output voltage of the PWM inverter when the PWM inverter is driven with a modulation rate smaller than the voltage 302. The same motor was driven by such voltages 301 and 302, respectively. The effective values of the voltages 301 and 302 are the same, and the rotational speed and torque of the motor are the same.

  FIG. 4 is a diagram illustrating an example of a magnetic flux density waveform (relationship between magnetic flux density and time) at the same location of the stator core when the motor is driven with voltages 301 and 302. As shown in FIG. 4, the magnetic flux densities 401 and 402 of the stator core are substantially the same regardless of which voltage 301 or 302 is used to drive the motor. The motor iron loss (total iron loss generated in the stator core and the rotor core) at this time was obtained by subtracting the machine output and the copper loss from the electric power supplied to the motor.

FIG. 5 is a diagram showing the results. In FIG. 5, A indicates that the motor is driven with the voltage 301, and B indicates that the motor is driven with the voltage 302. The iron loss ratio indicates the relative value of the iron loss when the iron loss of the stator core when the motor is driven at the voltage 301 is “1”. As shown in FIG. 5, it can be seen that the iron loss is significantly reduced when the motor is driven with the voltage 302 (B) than when the motor is driven with the voltage 301 (A). In addition, it has been confirmed that the motor efficiency of B is improved by about 5% and the inverter efficiency by about 7%, respectively.
Thus, the present inventors have found that even if the magnetic flux density generated in the magnetic material is the same, the iron loss of the magnetic material differs if the excitation voltage waveform (relationship between excitation voltage and time) is different. Obtained. This is considered that the difference in harmonics included in the excitation voltage becomes a difference in eddy current caused in the magnetic material constituting the core, resulting in a difference in iron loss. On the other hand, in order to obtain the magnetic flux density generated in the magnetic material by integrating the induced voltage induced by exciting the magnetic material, the signal of the high frequency component contained in the induced voltage is The magnetic flux density is considered to be the same because it is not included in the waveform. Therefore, the present inventors used not the magnetic flux density but the target waveform (target waveform) of the induced voltage induced by exciting the magnetic material and the measured waveform (measured waveform) of the induced voltage. Inspired to compare. The second embodiment of the present invention has been made based on the above knowledge and idea.

  Hereinafter, a second embodiment of the present invention will be described. Here, in the first embodiment described above, it is determined whether or not the measurement waveform of the magnetic flux density has converged to the target waveform. On the other hand, in this embodiment, it is determined whether or not the measurement waveform of the induced voltage has converged to the target waveform. As described above, the present embodiment and the first embodiment are mainly different in configuration and processing by using the induced voltage instead of the magnetic flux density. Therefore, in the description of the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in FIGS.

  FIG. 6 is a diagram illustrating an example of the configuration of the magnetic characteristic analysis system. FIG. 7 is a flowchart for explaining an example of a magnetic characteristic analysis method using the magnetic characteristic analysis system.

(Configuration of magnetic property analysis system)
In FIG. 6, the magnetic characteristic analysis system includes an excitation power source 101, an excitation coil 102, a search coil 103, a voltmeter 104, and an arithmetic device 610.
The arithmetic device 610 acquires the induced voltage measured by the voltmeter 104 as time series data based on a predetermined sampling period. The arithmetic device 610 generates an excitation voltage waveform and instructs the excitation power supply 101 to derive magnetic characteristics (information specifying hysteresis loss and eddy current loss) of the measurement sample S.

(Configuration of arithmetic unit 610 and magnetic characteristic analysis method)
Below, an example of the function which the arithmetic unit 610 has is demonstrated. The hardware of the arithmetic device 610 is realized by using, for example, an information processing device including a CPU, a ROM, a RAM, an HDD, and various interfaces, and dedicated hardware.

<Target waveform acquisition unit 611, S701>
The target waveform acquisition unit 611 acquires a target waveform for one cycle as a target waveform of the induced voltage (a target value of the induced voltage at each time). As an example of a method for acquiring the target waveform of the induced voltage, the following two methods will be described.

First, the first method will be described.
A search coil is wound around a predetermined region (region where magnetic properties are to be analyzed) of the core of the electrical device whose magnetic properties are to be analyzed. Then, an induced voltage (voltage across the search coil) induced in the search coil is measured by applying a predetermined excitation voltage to the excitation winding that excites the core of the electric device. It should be noted that the region around which the search coil is wound does not need to exactly match the region where the magnetic characteristics are to be analyzed, as described in the section <Target waveform acquisition unit 111, S201> of the first embodiment. It is.

Here, the number of turns and the area of the search coil 103 for the measurement sample S and the search coil for the electric device are different (in many cases). Therefore, according to this difference, it is necessary to convert the value of the induced voltage induced in the search coil for the electric device at each time into the value of the induced voltage induced in the search coil 103 for the measurement sample S at each time. (Refer to the formulas (1) and (2) described in the first embodiment). Specifically, the number of turns of the search coil 103 with respect to the measurement sample S and the cross-sectional area of the electromagnetic steel plate in the search coil 103 are N _A and S _A , respectively. The number of turns of the search coil for the electric device and the cross-sectional area of the electromagnetic steel sheet in the search coil are N _M and S _M , respectively. V _M (t) is an induced voltage induced in the search coil for the electric device. Then, the target waveform V _A (t) of the induced voltage is calculated by the following equation (12).
V _A (t) = {(N _A × S _A ) ÷ (N _M × S _M )} × V _M (t) (12)
The cross-sectional area of the electromagnetic steel sheet is an area of a cross section obtained by cutting the electromagnetic steel sheet in a direction perpendicular to the direction of the search coil axis (due to the magnetic flux generated in the measurement sample S when the measurement sample S is excited).

  Here, in order to reduce noise at the time of measurement, it is preferable to calculate the equation (12) after removing higher-order harmonic components contained in the induced voltage induced in the search coil for the electric device. For example, fast Fourier transform is performed on the waveform of the induced voltage induced in the search coil for the electrical device, and for example, the spectrum of the harmonic component of the 20th order or higher is removed, and then inverse Fourier transform is performed. As a result, higher-order harmonic components included in the induced voltage induced in the search coil for the electric device can be removed.

  The target waveform acquisition unit 611 can acquire the target waveform of the induced voltage, for example, by receiving the target waveform of the induced voltage from an external arithmetic device that calculates the target waveform of the induced voltage in this way. The target waveform acquisition unit 611 can also acquire the target waveform of the induced voltage by inputting the induced voltage induced in the search coil for the electric device and calculating the target waveform of the induced voltage. In addition, the target waveform acquisition unit 611 can also acquire the target waveform of the induced voltage by reading the target waveform data of the induced voltage from the storage medium that stores the target waveform data of the induced voltage.

Next, the second method will be described.
Two-dimensional numerical analysis based on Maxwell's equations for the magnetic flux density vector generated in a predetermined region of the core by applying a predetermined excitation voltage to the excitation winding that excites the core of the electrical device whose magnetic characteristics are to be analyzed ( It is obtained by performing numerical analysis on a plane parallel to the plate surface of the electrical steel sheet constituting the core (that is, numerical analysis in a two-dimensional space). In addition, the magnetic flux density vector calculated | required in this way has a component of the plate | board surface direction of the magnetic steel plate which comprises a core, and does not have a component of a plate | board thickness direction. The method for obtaining the magnetic flux density vector is the same as the second method described in the section of the target waveform acquisition unit 111 of the first embodiment, and thus detailed description thereof is omitted here.
Then, from the magnetic flux density vector for one cycle in a predetermined region of the core of the electrical device obtained as described above, a waveform for one cycle of the induced voltage is obtained based on the equations (1) and (2). The obtained waveform is set as a target waveform of the induced voltage.

  The target waveform acquisition unit 611 removes high-order harmonic components contained in the target waveform of the induced voltage calculated as described above (formally) in order to reduce errors in numerical analysis such as rounding error. ) It is preferable to use a target waveform of the induced voltage. For example, the target waveform acquisition unit 611 performs fast Fourier transform on the target waveform of the induced voltage calculated as described above, and removes, for example, the 20th-order or higher harmonic component spectrum, and then inverse Fourier transform I do. By doing so, it is possible to remove higher-order harmonic components contained in the target waveform of the induced voltage calculated as described above.

  The target waveform acquisition unit 611 can acquire the target waveform of the induced voltage by calculating the target waveform of the induced voltage as described above. In addition, the target waveform acquisition unit 611 receives the target voltage data of the induced voltage transmitted from an external computing device that calculates the target waveform of the induced voltage in the same manner as described above, thereby causing the target of the induced voltage. A waveform can also be acquired. The target waveform acquisition unit 611 can also acquire the target waveform of the induced voltage by reading the target waveform data of the induced voltage from the storage medium that stores the target waveform data of the induced voltage.

<Target waveform storage unit 612, S702>
The target waveform storage unit 612 stores the target waveform of the induced voltage acquired by the target waveform acquisition unit 611.
<Waveform correction unit 613, S703>
The waveform correcting unit 613 removes higher-order harmonic components included in the measurement waveform of the induced voltage measured by the voltmeter 104. For example, fast Fourier transform is performed on the measurement waveform of the induced voltage, and for example, the spectrum of the harmonic component of 20th order or higher is removed, and then the inverse Fourier transform is performed. Thereby, higher-order harmonic components included in the induced voltage induced in the search coil 103 with respect to the measurement sample S can be removed. Next, the waveform correcting unit 613 sets a value at a certain time of the measured waveform of the induced voltage from which the harmonic component is removed at a time corresponding to the time of the target waveform of the induced voltage stored in the target waveform storage unit 612. A value subtracted from the value is obtained at each time in one cycle (hereinafter, the value thus obtained is referred to as a difference). Then, the waveform correcting unit 613 adds a value obtained by multiplying the difference obtained with respect to a certain time by a relaxation coefficient to the value of the time corresponding to the current time of the waveform of the current excitation voltage. The waveform correcting unit 613 performs such correction by addition at each time in one cycle. The relaxation coefficient is for suppressing hunting of the excitation voltage, and has a value greater than 0 (zero) and less than 1. For example, a value of 0.2 to 0.3 can be adopted as the relaxation coefficient. Alternatively, the relaxation coefficient may be 1, and the difference may be added as it is to the current excitation voltage waveform. Here, by removing the harmonic component from the measurement waveform of the induced voltage in advance, it is possible to suppress hunting of the excitation voltage instruction waveform that cannot be suppressed even if the relaxation coefficient is used.

  At the start of measurement, there is no measurement waveform of induced voltage. Therefore, the waveform correction unit 613 employs the target waveform of the induced voltage stored in the target waveform storage unit 612 as the initial value of the excitation voltage instruction waveform. In this way, from the beginning of measurement, an excitation voltage having the same waveform as the target waveform is output from the excitation power supply 101, and the time until the convergence determination unit 614 described later determines that the induced voltage has converged is determined. Is preferable because it accelerates. However, the initial value of the instruction waveform of the excitation voltage is not limited to the target waveform of the induced voltage, and may be an arbitrary waveform.

<Convergence determination unit 614, S703 to S704>
The convergence determination unit 614 determines whether or not the measurement waveform of the induced voltage measured by the voltmeter 104 has converged to the target waveform of the induced voltage stored in the target waveform storage unit 612. In this embodiment, the convergence determination unit 614 uses the integrated value for one cycle of the absolute value of the difference between the target waveform of the induced voltage and the measured waveform at the time corresponding to each other, and the target waveform of the induced voltage is the target. It is determined whether or not the waveform has converged. Specifically, the target waveform of the induced voltage is V _A (t), the measured waveform of the induced voltage is V _P (t), and the start and end times of one cycle are t _s and t _e , respectively. The determination unit 614 determines that the measurement waveform of the induced voltage has converged to the target waveform when the following expression (13) is satisfied, and determines that the measurement waveform of the induced voltage has not converged to the target waveform otherwise. To do. In addition, the convergence determination unit 614 may use equation (14) instead of equation (13).

  Expression (13) is an example in the case where the integrated value for one cycle of the absolute value of the difference between the target waveform of the induced voltage and the measured waveform at the corresponding time is used as it is. Equation (14) is an integrated value for one cycle of the absolute value of the difference between the target waveform of the induced voltage and the measured waveform at the time corresponding to each other. It is an example at the time of expressing as a ratio with respect to an integrated value.

  The convergence determination unit 614 removes higher-order harmonic components included in the induced voltage induced in the search coil 103 with respect to the measurement sample S in order to reduce noise during measurement, and then the expression (13) or (14) It is preferable to calculate the formula. For example, the convergence determination unit 614 performs fast Fourier transform on the waveform of the induced voltage induced in the search coil 103 with respect to the measurement sample S, and removes, for example, the spectrum of the harmonic component of the 20th order or higher, and then performs the Fourier inverse. Perform conversion. By doing so, higher-order harmonic components included in the induced voltage induced in the search coil 103 with respect to the measurement sample S can be removed.

  When the convergence determination unit 614 determines that the induced voltage measurement waveform has not converged to the target waveform, the waveform correction unit 613 generates the excitation voltage instruction waveform described above. That is, the waveform correction unit 613 repeatedly generates the excitation voltage instruction waveform described above until the convergence determination unit 614 determines that the measurement waveform of the induced voltage has converged to the target waveform.

<Analysis unit 116, output unit 117, S705, S706>
When the convergence determination unit 614 determines that the measurement waveform of the induced voltage has converged to the target waveform, the analysis unit 116 derives the magnetic characteristics of the measurement sample S. Since the analysis unit 116 and the output unit 117 are the same as those in the first embodiment, detailed description thereof is omitted here.

(Summary)
As described above, in the present embodiment, the waveform correction unit 613 generates the instruction waveform of the excitation voltage according to the difference between the measurement waveform of the induced voltage induced in the measurement sample S and the target waveform, and the convergence determination unit The process is repeated until it is determined in 614 that the measurement waveform of the induced voltage has converged to the target waveform. The convergence determination unit 614 measures the induced voltage when the absolute value of the difference between the measured waveform of the induced voltage and the measured waveform at each time is equal to or less than a reference value using an integrated value for one period. It is determined that the waveform has converged to the target waveform. Therefore, in addition to the effects described in the first embodiment, even when a harmonic component is included in the excitation voltage and the harmonic component is included in the magnetic flux density in the measurement sample S, the harmonic component is extracted. There is an effect that can be done. Therefore, even when the magnetic flux density in the local region of the core of the electrical device is not a sine wave, the magnetic characteristics (hysteresis loss and eddy current loss) in the region can be derived with higher accuracy.

(Modification)
In this embodiment, the convergence determination unit 614 uses the integrated value for one cycle of the absolute value of the difference between the target waveform of the induced voltage and the measured waveform at the time corresponding to each other, and the measured waveform of the induced voltage becomes the target waveform. It is determined whether or not it has converged. However, this is not always necessary. The convergence determination unit 614 uses the result obtained by obtaining the difference (absolute value) of the amplitude of the same frequency component of the target waveform of the induced voltage and the measured waveform for each of the plurality of frequency components, and the target waveform of the induced voltage is the target. It may be determined whether or not the waveform has converged. Note that a specific example of the determination performed in this manner is the same as that described in the section of (Modification) of the first embodiment, and thus detailed description thereof is omitted here.

The embodiment of the present invention described above can be realized by a computer executing a program. Further, a computer-readable recording medium in which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
In addition, the embodiments of the present invention described above are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

[Example]
Next, examples will be described.
FIG. 8 is a diagram illustrating an example of a configuration of an IPM (Interior Permanent Magnet) motor 800 that is an electric device to be analyzed for magnetic characteristics. FIG. 8A shows a cross section of the IPM motor 800 cut along a direction perpendicular to the rotation axis thereof, and FIG. 8B is an enlarged view of the broken line region of FIG. It is. The outline of the specification of the IPM motor 800 used in the present embodiment is shown below.
Number of phases: 3
Number of poles: 4
Stator outer diameter: φ112 [mm]
Number of stator slots: 24
Rotor outer diameter: φ55 [mm]
Rotor stack thickness: 60 [mm]
Stator core and rotor core material: 35A300
Here, 35A300 is a non-oriented electrical steel sheet described in Non-Patent Document 5.

  As shown in FIG. 8B, the magnetic characteristics (hysteresis loss and eddy current loss) in the region 801 at the tip of the stator core teeth of the IPM motor 800 are represented by the method of the first invention example and the method of the second invention example. Sought in each of. The technique of the first invention example is the technique described in the first embodiment. The technique of the second invention example is the technique described in the second embodiment.

  In both the first invention example and the second invention example, the ratio of the hysteresis loss to the iron loss is 79 [%] (the ratio of the eddy current loss is 21 [%]). Could be derived. In this case, since the ratio of the hysteresis loss is larger than the ratio of the eddy current loss, the loss of the IPM motor 800 is obtained when the stator core is configured by using the electromagnetic steel sheet whose hysteresis loss is reduced by controlling the crystal orientation. It can be seen that can be reduced.

FIG. 9 is a diagram illustrating an example of a measurement waveform and a target waveform of the induced voltage. FIG. 9A shows a first invention example, and FIG. 9B shows a second invention example.
As shown in FIGS. 9A and 9B, it can be seen that the measurement waveform of the induced voltage is closer to the target waveform in the second invention example than in the first invention example. And the iron loss of the measurement sample S calculated | required by the 1st invention example became a value about 2 [%] lower than the iron loss of the measurement sample S calculated | required by the 2nd invention example. This is because, in the first invention example, the magnetic field strength is shifted because the excitation current corresponding to the target waveform of the induced voltage is not obtained due to the shift between the measured waveform of the induced voltage and the target waveform. In addition, it is considered that the harmonic component included in the induced voltage is not included in the magnetic flux density waveform.

[Relationship with Claims]
Hereinafter, an example of the correspondence between the claims and the embodiment will be described. Note that the description of the claims is not limited to the description of the embodiment, as described in the modification.
<Claims 1, 8, 9>
The applying unit is realized by using, for example, the excitation power source 101.
The first coil is realized by using, for example, the search coil 103.
The detection means is realized by using a voltmeter 104, for example.
The acquisition unit is realized, for example, by using the target waveform acquisition unit 611.
The determination unit is realized by using the convergence determination unit 614, for example.
The correcting means is realized by using the waveform correcting unit 613, for example.
The analysis unit is realized by using the analysis unit 116, for example.
Magnetic flux in the three-dimensional space of the measurement sample when the measurement sample is excited with the excitation voltage corrected by the correction means when the measurement waveform of the induced voltage converges to the target waveform of the induced voltage Deriving numerical solutions of the density vector and the eddy current vector includes, for example, an instruction waveform of the excitation voltage corrected by the waveform correction unit 114 when the measured waveform of the induced voltage converges to the target waveform of the induced voltage. Is applied to the exciting coil 102, and the magnetic flux density vector and eddy current vector generated in the measurement sample S are obtained by executing a three-dimensional numerical analysis based on Maxwell's equations.
Information specifying the hysteresis loss and eddy current loss in the measurement sample includes, for example, any two of hysteresis loss and eddy current loss, iron loss, hysteresis loss, and eddy current loss, iron loss, and hysteresis for iron loss. Or the ratio of eddy current loss.
The absolute value of the difference between the measured waveform of the induced voltage and the target waveform of the induced voltage at the time corresponding to each other corresponds to, for example, the correlation between the target waveform of the induced voltage and the measured waveform. The difference (absolute value) at the time to be used is used as it is, or the integrated value for one cycle of the absolute value of the difference at the time corresponding to the target waveform of the induced voltage and the measured waveform is the value of the target waveform of the induced voltage. This is realized by taking the ratio of the absolute value of the absolute value to the integrated value for one cycle (see the left side of (13) and the left side of equation (14)).
The difference in amplitude in each of the plurality of frequency components of the measurement waveform of the induced voltage and the target waveform of the induced voltage is obtained, for example, by obtaining a spectrum of the plurality of frequency components from each of the target waveform and the measurement waveform of the induced voltage, This is realized by taking the difference (absolute value) of the spectrum of the same frequency component in the target waveform and the measurement waveform of the induced voltage for each of the plurality of frequency components (the (modification) section of the second embodiment). reference).
<Claim 2>
The acquisition unit is realized by using the target waveform acquisition unit 111, for example.
The determination unit is realized by using the convergence determination unit 115, for example.
The correction means is realized by using the waveform correction unit 114, for example.
The analysis unit is realized by using the analysis unit 116, for example.
The measurement sample when the measurement sample is excited with the excitation voltage corrected by the correction means when the measurement waveform of the magnetic flux density in the measurement sample converges to the target waveform of the magnetic flux density in the measurement sample Deriving the numerical solution of the magnetic flux density vector and eddy current vector in the three-dimensional space is corrected by the waveform correcting unit 114 when the measured magnetic flux density waveform converges to the target magnetic flux density waveform, for example. The magnetic flux density vector and the eddy current vector generated in the measurement sample S by applying the excitation voltage instruction waveform to the excitation coil 102 are obtained by executing a three-dimensional numerical analysis based on Maxwell's equations.
The integrated value for one cycle of the absolute value of the difference between the measurement waveform of the magnetic flux density in the measurement sample and the target waveform of the magnetic flux density in the measurement sample at the corresponding time is, for example, the measurement of the target waveform of the magnetic flux density. The difference (absolute value) at the time corresponding to the waveform is used as it is, or the integrated value for one cycle of the absolute value of the difference at the time corresponding to the target waveform of the magnetic flux density and the measured waveform is used as the magnetic flux. This is realized by taking the ratio of the absolute value of the density target waveform value to the integrated value for one cycle (see the left side of (8) and the left side of equation (9)).
The difference in amplitude in each of a plurality of frequency components of the measurement waveform of the magnetic flux density in the measurement sample and the target waveform of the magnetic flux density in the measurement sample is, for example, a plurality of frequencies from each of the target waveform and the measurement waveform of the magnetic flux density. This is realized by obtaining the spectrum of the component and taking the difference (absolute value) of the spectrum of the same frequency component in the target waveform and measurement waveform of the magnetic flux density for each of the plurality of frequency components (in the first embodiment ( (Refer to “Modification”).
<Claims 3 and 6>
The magnetic flux density waveform derived based on the waveform of the induced voltage induced in the second coil wound around the predetermined region of the core is, for example, a predetermined region (magnetic characteristics of the core of the electric device). From the waveform of the induced voltage induced in the search coil wound around the region to be measured), the target waveform B (t) of the magnetic flux density in the predetermined region of the core of the electric device is obtained by the equations (1) and (2). This is realized by obtaining one period.
The waveform of the magnetic flux density in the predetermined region of the core obtained based on the numerical solution of the magnetic flux density vector in the two-dimensional space of the core applies a predetermined excitation voltage to the excitation winding that excites the core of the electrical device. Thus, the magnetic flux density vector generated in a predetermined region of the core is realized by obtaining one period by executing a two-dimensional numerical analysis based on Maxwell's equation.
<Claims 4 and 6>
The waveform of the induced voltage induced in the second coil wound around the predetermined region of the core is, for example, a search coil wound around a predetermined region (region where magnetic characteristics are to be measured) of the core of the electric device. This is realized by using a waveform of an induced voltage induced in the.
The waveform of the induced voltage derived based on the magnetic flux density in the predetermined region of the core obtained based on the numerical solution of the magnetic flux density vector in the two-dimensional space of the core excites the core of the electrical device, for example. By applying a predetermined excitation voltage to the excitation winding, a magnetic flux density vector generated in a predetermined region of the core is obtained for one period by performing a two-dimensional numerical analysis based on Maxwell's equations, It is calculated | required by calculating | requiring the waveform for one period of an induced voltage from the magnetic flux density vector for one period in the predetermined area | region of the core of an apparatus based on (1) Formula and (2) Formula.
<Claims 5 and 6>
The numerical solution of the magnetic flux density in the two-dimensional space of the core has a component in the plate direction of the magnetic material and does not have a component in the plate thickness direction of the magnetic material. This corresponds to having a component in the plate surface direction of the magnetic steel sheet constituting the core and not having a component in the plate thickness direction.
<Claim 7>
The numerical solution of the magnetic flux density vector and the eddy current vector in the three-dimensional space of the measurement sample has a component in the plate surface direction of the magnetic material and a component in the plate thickness direction of the magnetic material. The magnetic flux density vector corresponds to having a component in the plate surface direction and a component in the plate thickness direction of the electromagnetic steel plate constituting the core.

  101: excitation power source, 102: excitation coil, 103: search coil, 104: voltmeter, 110, 610: arithmetic unit, 111, 611: target waveform acquisition unit, 112, 612: target waveform storage unit, 113: derivation of magnetic flux density Part, 114, 613: waveform correction part, 115, 614: convergence determination part, 116: analysis part, 117: output part, S: measurement sample

Claims (10)

An application means for applying an excitation voltage to an excitation coil for exciting a measurement sample made of a magnetic material;
Detecting means for detecting an induced voltage induced in the first coil by exciting the measurement sample;
Obtaining means for obtaining a target waveform of the induced voltage;
Determination means for determining whether or not the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage;
When the determination means determines that the measurement waveform of the induced voltage has not converged to the target waveform of the induced voltage, based on the difference between the measurement waveform of the induced voltage and the target waveform of the induced voltage, Correction means for correcting the excitation voltage;
Magnetic flux in the three-dimensional space of the measurement sample when the measurement sample is excited with the excitation voltage corrected by the correction means when the measurement waveform of the induced voltage converges to the target waveform of the induced voltage An analytical means for deriving a numerical solution of a density vector and an eddy current vector, and deriving information for identifying a hysteresis loss and an eddy current loss in the measurement sample based on the derived numerical solution;
When the excitation voltage is corrected by the correction means, the application means applies the corrected excitation voltage to the excitation coil,
Until the determination means determines that the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage, the correction of the excitation voltage by the correction means, and the application of the excitation voltage by the application means, The detection of the induced voltage by the detection means is repeatedly performed,
The determination means includes an integrated value for one cycle of an absolute value of a difference between the measurement waveform of the induced voltage and the target waveform of the induced voltage at mutually corresponding times, or the measurement waveform of the induced voltage and the induced waveform. A magnetic characteristic characterized in that it is determined whether or not the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage based on a difference in amplitude of each of a plurality of frequency components of the voltage target waveform. Analysis system. The acquisition means further acquires a target waveform of magnetic flux density in the measurement sample,
In place of determining whether the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage, the determination unit is configured to determine whether the measurement waveform of the magnetic flux density in the measurement sample is a target of the magnetic flux density in the measurement sample. Determine whether it has converged to the waveform,
When the determination unit determines that the measurement waveform of the magnetic flux density in the measurement sample has not converged to the target waveform of the magnetic flux density in the measurement sample, the correction unit determines the measurement waveform of the induced voltage and the induction Based on the difference from the voltage target waveform, the excitation voltage is corrected,
The analysis means excites the measurement sample with the excitation voltage corrected by the correction means when the measurement waveform of the magnetic flux density in the measurement sample converges to the target waveform of the magnetic flux density in the measurement sample. Deriving numerical solutions of the magnetic flux density vector and eddy current vector in the three-dimensional space of the measurement sample,
The determination means is an integrated value for one cycle of an absolute value of a difference at a corresponding time between a measurement waveform of the magnetic flux density in the measurement sample and a target waveform of the magnetic flux density in the measurement sample, or the measurement sample The measurement waveform of the magnetic flux density in the measurement sample is obtained from the measurement waveform of the magnetic flux density in the measurement sample and the target waveform of the magnetic flux density in the measurement sample. The magnetic characteristic analysis system according to claim 1, wherein it is determined whether or not the target waveform has converged. In the predetermined region of the core when the core of the electric device having the core configured using the same kind of magnetic material as the magnetic material composing the measurement sample is excited under a predetermined excitation condition Obtain a magnetic flux density waveform as a target magnetic flux density waveform in the measurement sample,
The target waveform of the magnetic flux density in the measurement sample is a magnetic flux density waveform derived based on the waveform of the induced voltage induced in the second coil wound around the predetermined region of the core, or the core The magnetic characteristic analysis system according to claim 2, wherein the magnetic property analysis system is a waveform of magnetic flux density in the predetermined region of the core obtained based on a numerical solution of a magnetic flux density vector in a two-dimensional space. In the predetermined region of the core when the core of the electric device having the core configured using the same kind of magnetic material as the magnetic material composing the measurement sample is excited under a predetermined excitation condition Acquiring the waveform of the induced voltage as a target waveform of the induced voltage;
The target waveform of the induced voltage is based on the waveform of the induced voltage induced in the second coil wound around the predetermined region of the core or the numerical solution of the magnetic flux density vector in the two-dimensional space of the core. 4. The magnetic characteristic analysis system according to claim 1, wherein the magnetic characteristic analysis system is an induced voltage waveform derived on the basis of a magnetic flux density in the predetermined region of the core determined in this way. The core has a plurality of plate-like magnetic materials stacked on each other,
The shape of the magnetic material constituting the measurement sample is a plate,
The numerical solution of the magnetic flux density vector in the two-dimensional space of the core has a component in the plate surface direction of the magnetic material and does not have a component in the plate thickness direction of the magnetic material. Or the magnetic property analysis system according to 4.   The obtaining means obtains a numerical solution of a magnetic flux density vector and an eddy current vector generated in a two-dimensional space of the core when the core of the electrical device is excited under a predetermined excitation condition, based on a numerical analysis based on Maxwell's equations. The magnetic flux density waveform based on the numerical solution of the obtained magnetic flux density vector is acquired as a target waveform of the magnetic flux density in the measurement sample. Magnetic characteristic analysis system described in 1. The core has a plurality of plate-like magnetic materials stacked on each other,
The shape of the magnetic material constituting the measurement sample is a plate,
The numerical solution of a magnetic flux density vector and an eddy current vector in a three-dimensional space of the measurement sample has a component in the plate direction of the magnetic material and a component in the plate thickness direction of the magnetic material. The magnetic characteristic analysis system according to any one of 3 to 6.   The analysis means generates a magnetic flux generated in the three-dimensional space of the measurement sample when the measurement sample is excited with the excitation voltage corrected by the correction means when the measurement waveform converges to the target waveform. The magnetic characteristic analysis system according to claim 1, wherein a numerical solution of the density vector and the eddy current vector is obtained by performing a numerical analysis based on Maxwell's equations.   The correcting means removes higher-order harmonic components contained in the measured waveform of the induced voltage detected by the first detecting means, and then based on the difference from the target waveform of the induced voltage, The magnetic characteristic analysis system according to claim 1, wherein the excitation voltage is corrected. An application step of applying an excitation voltage to an excitation coil for exciting a measurement sample made of a magnetic material;
A detection step of detecting an induced voltage induced in the first coil by exciting the measurement sample;
An acquisition step of acquiring a target waveform of the induced voltage;
A determination step of determining whether the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage;
When it is determined by the determination step that the measurement waveform of the induced voltage has not converged to the target waveform of the induced voltage, based on the difference between the measurement waveform of the induced voltage and the target waveform of the induced voltage, A correction step of correcting the excitation voltage;
Magnetic flux in the three-dimensional space of the measurement sample when the measurement sample is excited with the excitation voltage corrected by the correction step when the measurement waveform of the induced voltage converges to the target waveform of the induced voltage An analysis step of deriving a numerical solution of a density vector and an eddy current vector, and deriving information for identifying a hysteresis loss and an eddy current loss in the measurement sample based on the derived numerical solution,
In the application step, when the excitation voltage is corrected by the correction step, the corrected excitation voltage is applied to the excitation coil,
Until the determination step determines that the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage, the correction of the excitation voltage by the correction step, the application of the excitation voltage by the application step, The detection of the induced voltage by the detection step is repeatedly performed,
The determination step includes an integrated value for one cycle of an absolute value of a difference at a corresponding time of the measured waveform of the induced voltage and the target waveform of the induced voltage, or the measured waveform of the induced voltage and the induced waveform. A magnetic characteristic characterized in that it is determined whether or not the measurement waveform of the induced voltage has converged to the target waveform of the induced voltage based on a difference in amplitude of each of a plurality of frequency components of the voltage target waveform. analysis method.

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