JP2012173280A - Iron loss distribution measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an iron loss distribution measuring apparatus capable of simply and accurately measuring iron loss both locally and overall.SOLUTION: An iron loss distribution measuring apparatus 1 measures distribution indicating respective positions and sizes of iron loss portions generated in an object 3 to be measured. The object 3 to be measured is placed in a vacuum state by a vacuum chamber 5. The iron loss distribution measuring apparatus 1 includes: an excitation section 6 for exciting the object 3 to be measured; a control section 17 for controlling excitation operation; a thermographic camera 9 for measuring temperature distribution data indicating the temperature distribution of the object 3 to be measured when the object 3 to be measured is excited; a temperature gradient average processing section 19 for finding out the distribution of temperature gradients in excitation based on a plurality of temperature distribution data measured a plurality of times in accordance with the lapse of time and performing average processing by using the plurality of temperature gradient distribution data; and a conversion section 21 for converting the temperature gradient distribution data whose temperature resolution is improved by the average processing into iron loss distribution data to measure iron loss distribution.

Description

  The present invention relates to an iron loss distribution measuring apparatus, and more particularly to an iron loss distribution measuring apparatus that measures a distribution indicating each position and each magnitude of an iron loss generated in a measurement object.

  First, electrical steel sheets are often used for electrical equipment, and the loss is roughly divided into copper loss, mechanical loss, and iron loss. Since the loss due to iron loss is converted into heat, it becomes a heat source in electrical equipment, and is said to be an obstacle to downsizing, and it is also said that measurement of iron loss is difficult. Therefore, the iron loss measurement is one of the basic measurements along with the measurement of the magnetization characteristics. The iron loss of electrical equipment is often evaluated by loss separation, and the remainder obtained by subtracting various losses from the overall loss is often the iron loss. In such a measurement, the overall average loss can be obtained by measuring with a power meter, etc. In addition to the question of accuracy, it is difficult to grasp the local iron loss distribution. It is. This is because the iron loss mainly occurs in the electromagnetic steel sheet, but is caused by the magnetic flux density, so it is not uniform and it is difficult to grasp the loss locally. On the other hand, in order to directly measure the iron loss, it is possible to measure with a small probe sensor and an H coil.

  On the other hand, since iron loss is converted into heat, the identification of the loss due to temperature rise is essential and is effective in identifying the loss. Therefore, in the direct measurement of the iron loss of an electromagnetic steel sheet, a method using a thermocouple or a thermistor by measuring the temperature locally has been proposed (for example, see Non-Patent Document 1 and Non-Patent Document 2).

  According to those reports, there is a temperature rise rate of about 0.0035 K / s at about 1.2 T, and a change rate of 0.14 μV is given to the thermocouple output. Therefore, it is necessary to amplify and record a minute thermoelectromotive force with good response. In thermistors and thermocouples, the responsiveness of the sensor affects the accuracy of iron loss measurement. Further, since the temperature change is minute, the influence of heat transfer with the outside world has been studied in detail, and it is shown that accurate measurement is possible within 5 to 10 seconds.

  Although not iron loss, an electric field / magnetic field distribution visualization device has been proposed as described in Patent Document 1, and it is also proposed to grasp the spatial distribution state of a magnetic field by visualizing with an infrared camera, for example. ing. In addition, as described in Non-Patent Document 3, research on visualization of iron loss distribution of magnetic domain images by the bitter method has also been reported.

JP 2001-663337 A

The Institute of Electrical Engineers of Japan The Journal of the Institute of Electrical Engineers of Japan VOL. 94-A, NO. 4, Apr. , 1974 (April 1974) Thermoelectric partial iron loss measurement method of electric iron plate Kenji Narita Masaaki Imamura p167 (39) -p174 (46) Journal of the Institute of Electrical Engineers of Japan The Journal of the Institute of Electrical Engineers June 98, 1978 Volume A, Volume 6 Takashi Yamamoto, Yoshihiro Oya, Tadao Nozawa, p331 (41) to p338 (46) Hosei University Information Media Center Research Report Vol. 21 Visualization of iron loss distribution in magnetic domain image by 2008 Bitter method Takashi Sunaga Chiko Saito p91-95

  However, since iron loss is a loss due to the magnetic flux density in the electrical steel sheet, it can be measured with a small probe sensor and H coil in order to directly measure the iron loss, but it is a local loss. However, there is a problem in accuracy and simplicity to make the total loss in some measurements. That is, it is difficult to grasp the iron loss locally by grasping the iron loss locally, simply and accurately.

  In addition, both of the measurement methods described in Non-Patent Document 1 and Non-Patent Document 2 have many constraints and are difficult to measure. In addition, in order to grasp the total loss, it is necessary to measure a plurality of measurement points by installing a temperature sensor locally, and the labor is too large to be suitable for measuring a large number of sample points. is there. In addition, in electrical equipment using electromagnetic steel sheets, the material is generally not uniformly magnetized, and may vary partially depending on magnetic flux conditions such as the magnitude, direction, and magnetic flux waveform of the magnetic flux density. It becomes a problem. In addition, since the magnetic steel sheet is polycrystalline, there is also a problem that the magnetic properties of the material itself are locally different. Furthermore, it has been reported that the magnetic steel sheet has an easy magnetization direction and a difficult direction due to rolling, and the magnetic characteristics are different from each other, which also causes a problem. Furthermore, the amount of heat that causes iron loss is very small, and there is a problem that a highly sensitive measurement of, for example, 0.003 degrees / Hz is required. Furthermore, since electrical steel sheets have heat transfer, it is desirable to measure in a short time in order to identify the source of loss, but there is a problem that the shorter the time, the smaller the temperature rise and the more difficult the measurement. .

  As described in Patent Document 1, if an infrared camera (thermographic camera) is also used, the temperature can be measured in a wide range at once by a simple method, and the demand for a large number of samples can be met, but the temperature resolution is low. If the measured data is used as it is, accuracy becomes a problem. In the method described in Non-Patent Document 3, the iron loss estimation using the magnetic domain image has a problem in accuracy because the iron loss is estimated from the size of the magnetic domain. Furthermore, in order to observe a magnetic domain, it is necessary to use an apparatus using the Kerr effect or X-rays, and there is a problem that there is a complexity in which the film of the electromagnetic steel sheet must be removed. In general, electromagnetic steel sheets are laminated to reduce loss by suppressing eddy currents. Therefore, in order to maintain insulation between the steel sheets, there is an insulating film of several microns. Seems to be usable, but there is a problem that it is difficult to deal with complex shapes like the actual machine.

  In other words, using any of the conventional techniques, it was not sufficient to measure the iron loss locally and simply by measuring the iron loss locally with high accuracy while increasing the degree of freedom of the shape of the measurement object. .

  Therefore, an object of the present invention is to provide an iron loss measuring apparatus that can easily and accurately measure the iron loss locally and as a whole while increasing the degree of freedom of the shape of the measurement object. .

  The invention according to claim 1 is an iron loss distribution measuring apparatus for measuring a distribution indicating each position and each size of the iron loss generated in the measurement object, wherein the measurement object is placed in a vacuum state, Excitation means for exciting the measurement object in a vacuum state, control means for controlling the operation of the excitation means, and the temperature distribution when the measurement object in the vacuum state is excited Temperature distribution measuring means for measuring the temperature distribution data shown by a single non-contact measurement, and a temperature during excitation based on a plurality of temperature distribution data measured by the temperature distribution measuring means a plurality of times over time A temperature gradient averaging processing means for obtaining a gradient distribution and performing an averaging process using the obtained distribution data of a plurality of temperature gradients, and a temperature gradient distribution obtained by improving the temperature resolution by the averaging process data It is converted into distribution data of iron loss is obtained and a conversion means for measuring the distribution of iron loss.

  According to a second aspect of the present invention, in the first aspect, the temperature distribution measuring means is a thermographic camera that measures a temperature distribution.

  According to a third aspect of the present invention, in the first or second aspect, the plurality of temperature distribution data is data obtained at a time interval at which the operation of the excitation means stops and the initial state can be regarded as constant.

  According to the first aspect of the present invention, first, the measurement object is placed in a vacuum to eliminate the influence of heat transfer by the atmosphere, thereby enabling measurement in a longer time than in the case of measurement in the atmosphere. The environment is ready. In addition, the temperature distribution data of the object to be measured can be obtained in a single non-contact process, and the temperature distribution data can be obtained directly and in a wide range as a basis for measuring the iron loss distribution. It is done. In this way, the non-contact measurement can provide an advantage that the degree of freedom of the shape of the measurement object may be high. Then, a temperature gradient distribution during excitation is obtained based on a plurality of temperature distribution data measured a plurality of times as time passes, and a temperature gradient averaging process is performed using the obtained temperature gradient distribution data. By converting the temperature gradient distribution data obtained by improving the temperature resolution by this averaging process into the iron loss distribution data, the iron loss distribution can be obtained directly in a wide range in a non-contact manner with high accuracy. be able to. In particular, according to the invention of claim 2, it is generally said that the thermographic camera has a minimum temperature sensitivity of about 0.02 degrees, but with this sensitivity, the iron loss is not measured by short-time measurement, but over time. By performing multiple measurements in response, the temperature gradient is averaged and the temperature resolution is improved, so that it is possible to overcome the conflicting problems of iron loss, which is simple and high precision that could not be overcome in the past. . Furthermore, according to the invention of claim 3, by setting an appropriate time interval after the excitation stop for a plurality of measurements according to the passage of time, the initial state is regarded as being constant (identical), and the influence other than the heat quantity due to loss. However, the heat loss of iron loss is small, but highly accurate measurement can be realized.

It is a block diagram which shows the outline of the iron loss distribution measuring apparatus concerning embodiment of this invention. It is a figure for demonstrating the temperature gradient measuring method. It is a figure which shows the standard deviation with respect to time of temperature distribution. It is a figure which shows the vector magnetic property apparatus as an analysis model. It is a figure which shows the analysis result of an iron loss distribution. It is a figure which shows the estimated iron loss distribution result calculated | required from the temperature gradient after 1 second and 10 seconds. It is the figure which showed the measurement model. It is a figure which shows the measurement result by the thermography camera of the measurement area A and the measurement area B of FIG. It is a figure which shows the maximum magnetic flux density distribution in the probe sensor of the measurement area A and the measurement area B of FIG. It is a figure which shows the maximum magnetic field strength distribution in the probe sensor of the measurement area A and the measurement area B of FIG.

  FIG. 1 is a block diagram showing an outline of an iron loss distribution measuring apparatus according to an embodiment of the present invention.

  The iron loss distribution measuring apparatus 1 includes a vacuum chamber 5 that accommodates the measurement object 3 therein, a thermography camera 9 that is disposed at a position that opposes an observation window 7 provided in the upper portion of the vacuum chamber 5, and a thermography camera 9. A moving mechanism 10 for moving the measuring object 3 to adjust the focal length for the camera, and a computer 15 connected to a thermographic camera 9 and an excitation unit 6 (described later) in the vacuum chamber 5 are provided.

  The vacuum chamber 5 uses a chamber in which a measuring device with a maximum degree of vacuum of about 0.001 Pa and a maximum diameter of 800 mm can be installed. Here, it is said that the temperature resolution of a general thermographic camera is inferior in sensitivity by 10 to 100 times compared to thermocouple measurement. Therefore, the measurement here requires long-time temperature measurement. On the other hand, if the object to be measured is in a vacuum, by eliminating the influence of heat transfer by the atmosphere, an environment that enables measurement in a longer time than in the case of measurement in the atmosphere is prepared. That is, heat transfer is negligible, and it is sufficient to consider the effects of heat conduction and radiant heat inside the measurement object (for example, a magnetic steel sheet). Therefore, as shown in FIG. 1, the measurement object 3 is accommodated in the vacuum chamber 5. An excitation unit 6 that excites the measurement object 3 is provided in the vacuum chamber 5. If only the measurement object is placed in a vacuum, normal use of a measuring device or the like becomes possible.

  The thermography camera 9 measures the temperature distribution of the measuring object 3 by infrared rays through the upper observation window 7. Therefore, the observation window 7 is made of sapphire glass (thickness 10 mm) that transmits infrared rays. Since the iron loss is proportional to the temperature gradient as will be described later, it is important to obtain the temperature gradient from the measured temperature result. The temperature gradient during excitation is obtained by measuring the temperature distribution a plurality of times. To be able to. Here, the specifications of the thermographic camera 9 will be described. A quantum sensor InSb FPA is used as a detector. The number of detector elements is 256 (H) × 256 (V), the detector cooling method is the Stirling cooler cooling method, the detection wavelengths are 3.5 to 4.1 μm, 4.5 to 5.1 μm, and the minimum temperature resolution is 0.8. The temperature is 025 ° C. or lower, and the number of acquired frames is 30 fps. The measured value of the thermographic camera 9 is obtained as an infrared count value. The temperature is usually obtained by correcting the infrared count value, but what is obtained in this measurement is a minimum temperature change, and it can be said that the gradient of the infrared amount and the temperature gradient have a linear relationship, and the calorific value is the infrared ray. It can be obtained from the slope of the count value.

  Next, the moving mechanism 10 includes a cylinder 11 that supports the measurement object 3 on its upper side, and a lift 13 that is connected to the lower side of the cylinder 11 and allows the measurement object 3 to move up and down. The moving mechanism 10 may be used to adjust the focal length visually, or to automatically adjust the focal length to a set distance by linking a sensor (not shown) for detecting the focal length, its detection output, and the lift 13. Good.

  The computer 15 includes a control unit 17, an averaging processing unit 19, a conversion unit 21, and a display unit 23. The control unit 17 includes a timer 25. The control unit 17 controls the excitation unit 6 that excites the measurement object 3 using the timer 25 and controls the thermography camera 9. The averaging processor 19 performs an averaging process on temperature gradient distribution data based on a plurality of temperature distribution data of the measurement object 3 obtained by imaging by the thermographic camera 9. This averaging process is a process for improving the temperature resolution by averaging the distribution data of a large number of temperature gradients. With this, the original temperature resolution of the thermographic camera 9 and the temperature at each position to be measured are measured. By solving the problem of the relationship with the accuracy for measuring the gradient (in other words, iron loss), the temperature gradient with high accuracy can be measured as a distribution. As described above, the gradient of the count value obtained from the infrared detector can also be used for the averaging process. In general, when the temperature is obtained from the infrared count value, since it is nonlinear, the gradient of the count value and the temperature gradient are different. However, in the case of a slight temperature change, it can be said that the count value and the temperature change are linear. Therefore, a value obtained by multiplying the gradient of the count value by a coefficient can be used as the iron loss value. Since the temperature gradient values of a plurality of times follow a normal distribution, the average value approaches the true value by averaging. Therefore, when accuracy of distribution is required, high accuracy that suppresses the spread of heat due to heat conduction by performing measurement (for example, 1 to 5 seconds, temperature rise is small) many times (10,000 times, etc.). It is possible to obtain a stable iron loss distribution. When the accuracy of the distribution is not required, it is possible to obtain the iron loss distribution by measuring about 100 times for 5 to 10 seconds (large temperature rise). The conversion unit 21 converts the distribution data of the temperature gradient after the averaging processing obtained by the averaging processing unit 19 into distribution data of iron loss. About this conversion (conversion processing to iron loss), the following two are mentioned as specific processing. First, the iron loss at a location where the change in magnetic flux density is relatively stable in the measurement region is measured using a probe sensor, and the magnitude and temperature gradient are compared to convert the iron loss value. Is possible. Second, measure the electrical resistance of the same steel sheet as the object to be measured, measure the temperature gradient using Joule heat as a heat source in advance by passing a controlled direct current, and the relationship between the temperature gradient and loss From this, it is possible to calculate the iron loss. And about this conversion result, the display part 23 displays the distribution of the iron loss which represents each position and each magnitude | size of the iron loss in a measuring object by the distribution data of the converted iron loss as a measurement result.

  FIG. 2 is a diagram for explaining a temperature gradient measurement method. In FIG. 2, the horizontal axis represents time, the vertical axis represents the count value of infrared rays, and the excitation time 10s is shown in the figure. The excitation method will be described with reference to FIG. In order to obtain a temperature gradient, 60 s / step was set, an interval of 50 s and an excitation time of 10 s were taken. Then, 500 steps are measured in order to average the temperature gradient. Thereafter, the averaging processing unit 19 obtains a gradient during the excitation time for each step and performs averaging. The interval time for averaging is determined to be 10 s by calculating the time during which the amount of heat after excitation is sufficiently averaged in the measurement region by two-dimensional heat conduction analysis described below.

The identification of the interval time by the two-dimensional heat transfer analysis will be described. The temperature distribution is calculated from the analysis result using the following governing equation of two-dimensional heat conduction along the xy axes. Regarding parameters, T is temperature (° C.), λ is thermal conductivity (W / (m · K)), Q is a heat source (W / m ³ ) (Note that Q of the heat source is iron obtained from simulation separately) Loss is calculated as a loss distribution), ρ is density (kg / m ³ ), c is specific heat (J / (kg · K)), and t is time (s).

  Here, specific heat and thermal conductivity depend on temperature. However, it can be said that the heat generated by the iron loss is extremely small, and the influence on the temperature is small. Therefore, the temperature dependence can be considered negligible. Further, since the outside air temperature is 0 ° C. and is in a vacuum, it is assumed to be completely insulated. As described above, the iron loss distribution is used as the heat source distribution. The iron loss distribution uses an analysis result using an integral E & S model and an organic element method in consideration of vector magnetic characteristics. The parameters used in the calculation are as shown in Table 1 below.

  When obtaining the distribution of iron loss due to temperature gradient, if the initial state is not the same, effects other than the heat quantity due to loss will occur. Since the amount of heat generated by iron loss is small, it is necessary to set an interval at which the influence is completely eliminated. The standard deviation with respect to time of the temperature distribution obtained by the following formula is shown in FIG. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the standard deviation of the temperature distribution. From the result of FIG. 3, the first 10 s is excited, and then the time and smoothing can be confirmed by heat conduction. Therefore, the interval time is set to 50 s, which can be said that the initial state is sufficiently constant.

  FIG. 4 is a diagram showing a vector magnetic characteristic device as an analysis model. FIG. 5 is a diagram showing the analysis result of the iron loss distribution. FIG. 6 is a diagram showing the estimated iron loss distribution result obtained from the temperature gradient after 1 second and after 10 seconds. Hereinafter, the relationship between the measurement time and the iron loss distribution will be described.

  When excitation is performed for a long time, the temperature rises and measurement becomes easy, but due to heat conduction, there is a difference between the iron loss distribution and the temperature gradient distribution. Therefore, measurement in a short time is indispensable to improve the distribution accuracy. In this report, the excitation time is 10 seconds. Therefore, the accuracy of excitation time and distribution is examined. The analysis conditions were the same as described above, and the analysis model was the vector magnetic characteristic device shown in FIG. The evaluation area was a sample of 80 mm × 80 mm. The result was obtained as an analysis result of the iron loss distribution shown in FIG. Excitation conditions were alternating magnetic flux, central maximum magnetic flux density 1T, and easy magnetization. When this distribution is subjected to heat conduction analysis using Equation 1 as a heat source, as shown in FIG. 6, the temperature gradient after 1 second (FIG. 6 (A)) and after 10 seconds (FIG. 6 (B)). The iron loss distribution results obtained from the above were obtained. It can be seen that the distribution is widened by heat conduction after 1 second and after 10 seconds. One second later is closer to the iron loss distribution, but when the calorific value is large, it is about 0.0025K, which indicates that measurement is difficult. After 10 seconds, 10 times the temperature after 1 second is obtained, so measurement is possible. Moreover, it turns out that the distribution tendency of an iron loss is fully obtained.

  FIG. 7 is a diagram showing a measurement model. This model core simulates the shape of a three-phase transformer, but has a shape in which a window hole is formed in one directional electromagnetic steel sheet. Therefore, unlike a normal three-phase transformer, it is a model having a rolling perpendicular direction in the magnetic path. The number of laminated layers is 27, B coils are applied, and the maximum magnetic flux density is controlled to a target value. The excitation waveform is a sine wave, and the waveform shape is not controlled. In general, the infrared emissivity of metal is about 0.6, which is worse when the surface is smooth. Therefore, the measurement area is painted black to increase the infrared emissivity. The measurement conditions are as shown in the measurement parameters in Table 2 below. The excitation coil was applied to the center, the excitation frequency was 50 Hz, the maximum magnetic flux density of the search coil was 0.5 T, the image acquisition speed was 30 fps, the averaging count was 1000 times, and a Median filter was used as an image filter.

  8-10 is a figure which shows the various measurement results of the measurement area A and the measurement area B of FIG. 8A shows a measurement result by the thermography camera in the measurement area A, and FIG. 8B shows a measurement result by the thermography camera in the measurement area B. FIG. 9 and FIG. 10 show the results of measuring the magnetic characteristics with the probe sensor because the magnetic characteristics cannot be measured with the thermography camera. 9A shows the maximum magnetic flux density distribution (T) in the measurement area A, and FIG. 9B shows the maximum magnetic flux density distribution (T) in the measurement area B. 10A shows the maximum magnetic field strength distribution (A / m) in the measurement area A, and FIG. 10B shows the maximum magnetic field strength distribution (A / m) in the measurement area B. Table 3 below shows the specifications of the probe sensor. The measurement pitch is 2 mm.

  In area A, a large iron loss value can be observed in the direction perpendicular to the rolling. It can also be seen that the iron loss value is smaller in the rolling direction than in the direction perpendicular to the rolling direction. On the other hand, in the magnetic flux density distribution of FIG. 9A, it can be seen that the value is large in the rolling direction. From the magnetic field strength distribution shown in FIG. 10 (A), it can be seen that the magnetic field strength is increased in the direction perpendicular to the rolling. The grain-oriented electrical steel sheet, which is a material of this model, has the characteristics that the magnetic anisotropy is large, the magnetic properties in the rolling direction are excellent, and the loss is small. Therefore, it is clear that the magnetic flux density is large but the iron loss tends to be small.

  In the area B, as in the area A, it can be seen that the loss is large in the direction perpendicular to the rolling and the loss is small in the rolling direction. It can also be seen that iron loss is concentrated in the corner. The magnetic flux density distribution shown in FIG. 9B and the magnetic field strength distribution shown in FIG.

  In summary, the points are as follows.

  First, it has become possible to directly measure the iron loss distribution of electrical equipment (magnetic steel sheets) using a thermographic camera. As a result, the temperature distribution data of the measurement object can be obtained in a single non-contact manner, and the temperature distribution data can be directly obtained in a wide range and non-contact as the basic data for measuring the iron loss distribution. . In this way, the non-contact measurement can provide an advantage that the degree of freedom of the shape of the measurement object may be high.

  Secondly, we succeeded in capturing the minimal change in calorie in the distribution by performing the averaging process by repeated measurement of the point that the temperature sensitivity is inferior compared to the thermistor and thermocouple which are the conventional measurement methods. That is, a temperature gradient distribution during excitation is obtained based on a plurality of temperature distribution data measured a plurality of times over time, and temperature gradient averaging processing is performed using the obtained temperature gradient distribution data. By converting the temperature gradient distribution data obtained by improving the temperature resolution by this averaging process into the iron loss distribution data, the iron loss distribution can be obtained directly in a wide range in a non-contact manner with high accuracy. I was able to. In general, it is said that the temperature sensitivity of a thermographic camera is a minimum of about 0.02 degrees, but with this sensitivity, it is not necessary to measure iron loss by short-time measurement, but to perform multiple measurements over time. Thus, by performing temperature gradient averaging processing and improving the temperature resolution, it was possible to overcome the contradictory problems of the iron loss of simplicity and high accuracy that could not be overcome in the past.

  Thirdly, in order to avoid heat conduction in the atmosphere, it has become possible to measure a minimum temperature using a vacuum chamber. That is, by placing the measurement object in a vacuum and eliminating the influence of heat transfer by the atmosphere, it was possible to prepare an environment that enables measurement in a longer time than in the case of measurement in the atmosphere.

  Fourthly, it has been clarified that the initial state can be made the same by providing an interval of 50 s for 10 s excitation by heat conduction analysis using the iron loss distribution obtained by vector magnetic characteristic analysis as a heat source. . In other words, by setting an appropriate time interval after the excitation stop, the initial state can be regarded as constant (same), and the effects other than the heat quantity due to loss can be eliminated. It was clarified that the measurement can be realized.

  Fifth, the model core was measured and a reasonable measurement result was obtained. Sixth, the result of measuring the model by the probe method and the iron loss distribution measured by the thermography camera were compared, and the characteristics of the grain-oriented electrical steel sheet were taken into account, and it was found that the distribution was reasonable.

  In recent years, interest in energy saving has increased interest in electric vehicles using motors with high energy conversion efficiency. In the case of a moving body such as an electric vehicle, the weight of the motor itself also contributes to the efficiency of the entire vehicle, so a small and lightweight motor is desired. Moreover, since the energy product of a battery is small compared with a fossil fuel, an efficient motor is desired. Although it is a motor that is much more efficient than an internal combustion engine, various studies have been conducted to further improve efficiency. Generally, motor loss includes “iron loss”, “copper loss”, and “mechanical loss”. Each loss is an inherent loss that occurs in an electromagnetic steel plate, a copper wire, a bearing, or the like, which is a constituent material of the motor. Therefore, the motor is important as an object for measuring iron loss.

DESCRIPTION OF SYMBOLS 1 ... Iron loss distribution measuring apparatus, 3 ... Measuring object, 5 ... Vacuum chamber, 6 ... Excitation part, 9 ... Thermography camera, 17 ... Control part, 19 ... Averaging processing unit, 21 ... conversion unit

Claims (3)

An iron loss distribution measuring device for measuring a distribution indicating each position and each size of iron loss generated in a measurement object,
The measurement object is placed in a vacuum state,
Excitation means for exciting the measurement object in the vacuum state;
Control means for controlling the operation of the excitation means;
Temperature distribution measuring means for measuring temperature distribution data indicating the temperature distribution when the measurement object placed in the vacuum state is excited by a single non-contact measurement;
The temperature distribution measuring means obtains a temperature gradient distribution during excitation based on a plurality of temperature distribution data measured a plurality of times over time, and performs an averaging process using the obtained temperature gradient distribution data. A temperature gradient averaging means to perform;
An iron loss distribution measuring apparatus comprising: a conversion means for measuring distribution of iron loss by converting distribution data of temperature gradient obtained by improving the temperature resolution by the averaging process into distribution data of iron loss.   The iron loss distribution measuring apparatus according to claim 1, wherein the temperature distribution measuring unit is a thermographic camera that measures a temperature distribution.   The iron loss distribution measuring apparatus according to claim 1 or 2, wherein the plurality of temperature distribution data are data obtained at a time interval in which the operation of the excitation means is stopped and the initial state can be regarded as constant.