JP2011226840A - Method and device for measurement of magnetic characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for measurement of magnetic characteristics capable of correlating and appropriately displaying dynamically changing magnetic characteristics and loss measurement information of various magnetic materials.SOLUTION: In the method and device for measurement of magnetic characteristics, a B-H curve is obtained by exciting a target magnetic material with the use of an AC exciting signal and measuring a flux density B and a field intensity H, and loss measurement information of the target magnetic material in a chronological order is arranged and displayed along the time base of the B-H curve.

Description

  The present invention relates to a magnetic characteristic measuring method and a magnetic characteristic measuring apparatus, and more particularly to an improvement of a magnetic characteristic measuring method and a magnetic characteristic measuring apparatus suitable for dynamic magnetic characteristic evaluation of various magnetic materials in a high frequency region.

  Magnetic materials are widely used for various applications in various industrial fields. For example, motors as various power drive sources in hybrid cars and inverters that convert DC power into AC power supply are composed of magnetic materials as important basic components.

  However, in hybrid cars that are attracting attention from the viewpoints of energy saving and environmental protection, “growing noises” generated by motors and inverters have been pointed out as annoying noises that impair the comfort in the vehicle. This is due to the fact that frequency components that are felt as annoying noise are included in the drive frequency region that changes in conjunction with the accelerator.

That is, when a magnetic field is applied to the metal, a minute expansion and contraction of 10 ⁻⁶ m called “magnetostriction” occurs in the metal. This magnetostriction vibrates the surrounding air and generates a sound called “magnetostriction sound”. However, depending on the driving frequency, it becomes a high-frequency “beat sound” as described above, which is uncomfortable for hybrid car users. Will be given.

  On the other hand, in order to reduce the size, capacity, and efficiency of parts and devices using magnetic materials, aiming at several tens KHz to several hundreds KHz for general-purpose inverters and tens of MHz for UPS (Uninterruptible Power Supply), Increasing driving frequency is being accelerated.

  In driving the inverter, instead of the sine wave drive, the sine wave signal is superimposed with a pulse width signal having a predetermined amplitude and adjusted so that the pulse width changes according to the change of the sine wave. The zero level line of the pulse width signal is also driven by a pseudo sine wave signal that is changed stepwise at an interval of 1/12 of the sine wave signal period, for example.

  In this case, since the change in the output voltage of the inverter is very small, the switching loss of the semiconductor element can be greatly reduced. Further, since the output waveform of the inverter is a pseudo sine wave, a subsequent smoothing filter is not required, and the capacity can be greatly reduced, so that the loss in the filter circuit can be reduced.

  Furthermore, when attention is paid to the actual excitation state of a power source using a magnetic material, the rectangular wave excitation is almost more than the sine wave excitation. However, since the square wave contains higher-order harmonic components, the iron loss represented by the sum of hysteresis loss and eddy current loss increases as compared to sinusoidal excitation, and the difference becomes even greater as the frequency increases. .

  Here, iron loss is electrical energy lost when a coil is wound around an iron core (core) of a magnetic material and magnetized by alternating current, and combined with copper loss, which is electrical energy lost due to the resistance of the coil lead wire, Reduce the efficiency of electric machines such as electric motors, generators and transformers.

  The hysteresis loss is a loss when the magnetic domain of the iron core changes the direction of the magnetic field by an alternating magnetic field, and this loss is represented by a loop-like hysteresis curve (BH curve), the magnitude of which is a circle of this hysteresis curve. It is proportional to the area of the part surrounded by.

  Eddy current loss is caused by eddy current generated in the iron core, and the ratio of eddy current loss increases as the frequency becomes higher as described above. In order to make it difficult for such eddy currents to flow, use a material with high permeability and low conductivity, or insulate both sides with attention to the fact that the magnitude of eddy current is proportional to the square of the plate thickness. Measures such as using thin materials applied in layers are taken.

  In research and development and manufacturing inspection of these various magnetic materials, it is desirable that the measurement results of desired measurement items including the magnetic characteristics and various loss information of the magnetic material to be measured can be obtained efficiently and with high accuracy.

  5A and 5B are explanatory diagrams of a conventional method for measuring static magnetic properties of a magnetic material that is generally performed. FIG. 5A shows an example of an excitation signal, and FIG. 5B shows an excitation signal of FIG. Shows an example of a static BH curve obtained by exciting at.

  In FIG. 5, the excitation signal is only an AC fundamental wave component as shown in (A), and the BH curve is only a major loop as shown in (B). A characteristic value such as iron loss in a steady state is obtained based on a static BH curve as shown in (B), and a characteristic value in an actual use environment is also estimated.

  6A and 6B are diagrams for explaining the operation in an actual use environment of a magnetic material, where FIG. 6A shows an example of an excitation signal, and FIG. 6B shows an example of a BH curve when excited by the excitation signal of FIG. Show.

  In FIG. 6, the excitation signal in the actual use environment has a high frequency component superimposed on an alternating fundamental wave component as shown in FIG. In the BH curve, as shown in (B), there are a major loop corresponding to the fundamental component of the alternating current, and a plurality of minor loops caused by high-frequency components partially connected inside the major loop. Appears.

  Patent Document 1 discloses a reactor loss measurement method that accurately calculates only the iron loss due to switching ripple over the entire output period of the PWM inverter, and also describes a major loop and a dynamic minor loop. Yes.

JP 2008-122210 A

  However, according to the conventional method of estimating the characteristic value in the actual use environment based on the static BH curve, the dynamics of the magnetic material to be measured exerted by a plurality of minor loops caused by high frequency components It is difficult to appropriately reflect the magnetic characteristics, and there is a problem that an error becomes large.

  As a method for solving such problems, a method for measuring a static minor loop by adding an offset to the excitation signal and a method for measuring by exciting with an excitation signal simulating an actual use environment have been proposed. However, the display of the measurement result is the display by the BH curve similar to the conventional one, and it is difficult to appropriately display the dynamic characteristics of the magnetic material to be measured, and the loss information is displayed in association with it. I can't.

  The present invention pays attention to such a conventional problem, and the purpose thereof is a magnetic characteristic measurement method capable of appropriately displaying the magnetic characteristics and loss measurement information of various magnetic materials that change dynamically in association with each other. And providing a magnetic property measuring apparatus.

  The invention of claim 1 which achieves such a problem is to obtain a BH curve by exciting a magnetic material to be measured with an alternating current excitation signal and measuring a magnetic flux density B and a magnetic field strength H to obtain the BH curve. It is a magnetic characteristic measuring method characterized by arranging and displaying time-series loss measurement information of a magnetic material along the time axis of the BH curve.

  According to a second aspect of the present invention, in the magnetic characteristic measuring method according to the first aspect, a plurality of the BH curves are obtained in time series, and the plurality of BH curves are discretely displayed along the time axis. In addition, the time-series loss measurement information of the magnetic material to be measured is arranged and displayed along the time axis of each BH curve.

  According to a third aspect of the present invention, in the magnetic characteristic measuring method according to the first or second aspect, the AC excitation signal includes a high frequency component superimposed on a fundamental wave component, and the BH curve is the high frequency component. It includes a minor loop of a plurality of BH curves caused by components.

  According to a fourth aspect of the present invention, in the magnetic characteristic measuring method according to any one of the first to third aspects, the loss measurement information is an optical displacement that optically detects a minute shape change of the magnetic material to be measured. It is magnetostriction measurement information based on a detection signal.

The invention of claim 5
Excitation means for exciting the magnetic material to be measured with an AC excitation signal;
BH curve generating means for measuring magnetic flux density B and magnetic field strength H of the excited magnetic material to be measured, and generating a plurality of BH curves along the time axis;
Loss information measuring means for measuring time-series loss information of the magnetic material to be measured;
The plurality of BH curves are discretely arranged and displayed along a time axis, and time-series loss measurement information of the magnetic material to be measured is arranged and displayed along the time axis of each BH curve. 3D display means,
And a magnetic characteristic measuring device characterized by comprising:

  According to a sixth aspect of the present invention, in the magnetic property measuring apparatus according to the fifth aspect, the AC excitation signal is a signal in which a high frequency component is superimposed on a fundamental wave component, and the BH curve is caused by the high frequency component. It includes a minor loop of a plurality of BH curves.

  According to a seventh aspect of the present invention, in the magnetic characteristic measuring apparatus according to the fifth or sixth aspect, the loss information measuring unit is an optical displacement detecting unit that optically detects a minute shape change of the magnetic material to be measured. It is characterized by being.

  As a result, the magnetic characteristics and magnetostriction measurement information of various magnetic materials that change dynamically can be appropriately displayed in association with each other in time series.

It is explanatory drawing which shows one Example of the display form based on this invention. It is explanatory drawing which shows the other Example of the display form based on this invention. It is explanatory drawing which shows the other Example of the display form based on this invention. It is a configuration explanatory view showing an embodiment of the present invention. It is explanatory drawing of the static magnetic characteristic measuring method of the magnetic material generally performed conventionally. It is operation | movement explanatory drawing in the actual use environment of a magnetic material.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing an embodiment of a display form according to the present invention.

  In FIG. 1, in (A), the magnitude of magnetostriction measurement information as time-series loss measurement information of the magnetic material to be measured is represented by the length of a line segment, and the static shown in FIG. Are arrayed discretely along the time axis of a major loop of a typical BH curve. On the other hand, in (B), the magnitude of the amplitude of magnetostriction measurement information as time-series loss measurement information of the magnetic material to be measured is represented by the length of the line segment, and the dynamics continuously along the time axis. Discretely arranged on a BH curve.

  FIG. 2 is an explanatory view showing another embodiment of the display form according to the present invention.

  2A, the magnitude of magnetostriction measurement information as time-series loss measurement information of the magnetic material to be measured is shown in FIG. It is displayed discretely along the time axis of the major loop of the static BH curve. On the other hand, in (B), the magnitude of the amplitude of magnetostriction measurement information as time-series loss measurement information of the magnetic material to be measured is shown in FIG. It is displayed discretely along the time axis of a dynamic BH curve in which a plurality of minor loops appear due to high-frequency components partially connected inside the major loop.

  According to these display forms, the BH curve and the magnetostriction measurement information as the loss measurement information are displayed in association with each other in time series. For example, “magnetostriction sound” and BH as described above are displayed. It is possible to visually grasp the correlation with the curve and intuitively confirm the effect when various measures are taken to reduce "magnetostriction" on the display screen.

  FIG. 3 is a display example of a dynamic BH curve. FIG. 3A shows an example in which the BH curve continues spirally along the direction of the time axis T without closing, and FIG. An example is shown in which a plurality of BH curves closed for each measurement cycle are arranged and displayed along the direction of the time axis T. By applying the display form based on the present invention shown in FIGS. 1 and 2 to the BH curve in FIG. 3 as well, the BH curve and magnetostriction measurement information as loss measurement information are correlated in time series. Can be displayed.

  FIG. 4 is a structural explanatory view showing an embodiment of the magnetic property measuring apparatus according to the present invention. In FIG. 4, the magnetic material 1 to be measured is excited by a predetermined excitation signal by the excitation signal generator 2a. As such an excitation signal generator 2a, for example, an arbitrary waveform generator or a function generator capable of outputting an arbitrary waveform may be used.

  The current measurement unit 2b measures the current flowing through the measurement target magnetic material 1 in the excited state via the detection coil, and the voltage measurement unit 2c measures the voltage applied to the measurement target magnetic material 1 in the excitation state via the detection coil. To do. These measurement data are sequentially stored in the measurement data storage unit 2g together with the measurement time data. For example, a digital oscilloscope may be used as the current measuring unit 2b and the voltage measuring unit 2c.

  The loss information measurement unit 2d measures a minute shape change due to magnetostriction of the magnetic material 1 to be measured in an excited state, and uses, for example, an optical displacement meter. The vibration wave and sound wave of the magnetic material 1 to be measured in the excited state have a waveform similar to the current waveform. If an optical displacement meter is used, vibration and sound components can be detected and measured over a wider band than in the case of measuring with a vibration sensor or microphone. These measurement data are also sequentially stored in the measurement data storage unit 2g together with the measurement time data.

  The measurement target parameter storage unit 2e stores parameters such as the cross-sectional area and magnetic path length of the magnetic material 1 to be measured.

  The operation input unit 2f is an interface for an operator to input commands and instructions necessary for a series of measurements to the apparatus.

The magnetic flux density calculator 2h calculates the magnetic flux density B based on a predetermined arithmetic expression shown in the following expression.
Magnetic flux density B = Integ (C1) / (K1 * K2)
here,
Integ represents an integral operation,
C1 is a voltage measured by the voltage measuring unit 2c,
K1 is the number of turns of the pickup coil (B coil),
K2 is the cross-sectional area of the magnetic material 1 to be measured.

The magnetic field strength calculation unit 2i calculates the magnetic field strength H based on a predetermined calculation formula shown in the following formula.
Magnetic field strength H = C2 * K4 / K3
here,
C2 is the current measured by the current measuring unit 2b,
K3 is the magnetic path length of the magnetic material 1 to be measured,
K4 is the number of turns of the main winding (H coil).

  The BH curve generation unit 2j displays the display as shown in FIGS. 1 to 3 based on the measurement data stored in the measurement data storage unit 2g and the calculation results of the magnetic flux density calculation unit 2h and the magnetic field strength calculation unit 2i. Generate a BH curve to do.

  The iron loss calculation unit 2k calculates the iron loss of the magnetic material 1 to be measured based on, for example, the BH curve generated by the BH curve generation unit 2j.

  The BH curve related information superimposing unit 2m adds time series magnetostriction information of the measurement target magnetic material 1 measured by the loss information measuring unit 2d to the BH curve generated by the BH curve generating unit 2j. The iron loss calculated by the iron loss calculation unit 2k is superimposed so as to be displayed in a desired form as shown in FIGS. 1 and 2, for example.

  The BH curve three-dimensional display generation unit 2n generates a BH curve generated by the BH curve generation unit 2j and displayed two-dimensionally on the (XY) axis, as shown in FIG. A display screen for expanding and displaying along T (Z axis) is generated.

  The BH curve three-dimensional display generation unit 2n performs processing so as to separate and display a plurality of minor loops in the BH curve shown in FIG. 2B, for example, along the time axis as necessary. You can also.

  Furthermore, the BH curve three-dimensional display generation unit 2n can perform processing so as to rotate and display the three-dimensional display image of the BH curve at an arbitrary angle as necessary. Thereby, display observation that focuses only on a specific relationship such as XY, XZ, YZ, and XYZ can also be performed.

  The display unit 2p displays each image generated by each unit in a desired display form as shown in FIGS. 1 to 3, and uses, for example, a flat display panel such as a liquid crystal.

  The control unit 2q controls the overall operation of the apparatus, and is connected to each part of the apparatus via the bus B, for example. When each unit is configured by a single independent device, the bus B functions as a network connecting the devices.

  According to the configuration of FIG. 4, the measurement result that has been conventionally displayed as trace information on the XY plane is displayed as three-dimensional trace information with the time information at which the value was observed added as the Z axis. Since the BH curve and magnetostriction measurement information as loss measurement information are displayed in a time series relationship with each other, for example, the “magnetostriction sound” as described above and the BH curve are mutually displayed. The relationship can be confirmed intuitively on the display screen.

  In the above-described embodiment, the description has been made by paying attention to the “beat noise” generated from the motor or inverter of the hybrid car. It is also effective for dynamic magnetic property evaluation of magnetic materials such as various transformers used in power supplies and various motors used in factories and homes.

  As described above, according to the present invention, a magnetic characteristic measuring method and a magnetic characteristic measuring apparatus suitable for dynamic magnetic characteristic evaluation of various magnetic materials in a high frequency region can be realized.

DESCRIPTION OF SYMBOLS 1 Magnetic material to be measured 2a Excitation signal generation part 2b Current measurement part 2c Voltage measurement part 2d Loss information measurement part 2e Measurement object parameter storage part 2f Operation input part 2g Measurement data storage part 2h Magnetic flux density calculation part 2i Magnetic field strength calculation part 2j B -H curve generation unit 2k Iron loss calculation unit 2m BH curve related information superimposition unit 2n BH curve three-dimensional display generation unit 2p display unit 2q control unit

Claims (7)

A magnetic material to be measured is excited with an AC excitation signal, and a magnetic flux density B and a magnetic field strength H are measured to obtain a BH curve.
A method for measuring magnetic characteristics, characterized in that time-series loss measurement information of the magnetic material to be measured is arranged and displayed along the time axis of the BH curve. Obtaining a plurality of BH curves in time series;
A plurality of BH curves are discretely arranged and displayed along the time axis, and time-series loss measurement information of the magnetic material to be measured is arranged and displayed along the time axes of the BH curves. The magnetic property measuring method according to claim 1.   2. The AC excitation signal is obtained by superimposing a high frequency component on a fundamental wave component, and the BH curve includes a plurality of BH curve minor loops resulting from the high frequency component. Or the magnetic characteristic measuring method of Claim 2.   The loss measurement information is magnetostriction measurement information based on an optical displacement detection signal for optically detecting a minute shape change of the magnetic material to be measured. Magnetic property measurement method. Excitation means for exciting the magnetic material to be measured with an AC excitation signal;
BH curve generating means for measuring magnetic flux density B and magnetic field strength H of the excited magnetic material to be measured, and generating a plurality of BH curves along the time axis;
Loss information measuring means for measuring time-series loss information of the magnetic material to be measured;
The plurality of BH curves are discretely arranged and displayed along a time axis, and time-series loss measurement information of the magnetic material to be measured is arranged and displayed along the time axis of each BH curve. 3D display means,
A magnetic property measuring apparatus characterized by comprising:   6. The AC excitation signal is obtained by superimposing a high frequency component on a fundamental wave component, and the BH curve includes a plurality of BH curve minor loops resulting from the high frequency component. The magnetic characteristic measuring apparatus described in 1. The loss information measuring means includes
7. The magnetic characteristic measuring apparatus according to claim 5, wherein the magnetic characteristic measuring device is an optical displacement detecting means for optically detecting a minute shape change of the magnetic material to be measured.