JP2738539B2 - AC magnetic property measurement method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for measuring AC magnetic characteristics in the operation of a magnetic core with a magnetic amplifier.

[Prior Art] In a magnetic amplifier, AC magnetic characteristics of a magnetic core performing a minor loop operation including a saturation region typified by a saturable magnetic core are generally evaluated from two points of the amplification degree of the magnetic core and the core loss. As a method for evaluating the amplification of the magnetic core,
CMC using the circuit shown in the figure
tization Characteristics) are known. FIGS. 7 and 8 show waveforms of respective parts and measurement results at the time of measurement in this circuit. In FIG. 8, the operating magnetic flux density amount ΔBcm and the control magnetizing force H are obtained by the following equations.

vs: Detection winding end voltage (V) Ic: Control current (A) Ns: Number of turns of detection winding Nc: Number of turns of control winding Ae: Effective core area (m ² ) le: Average magnetic path length (m) In the CMC shown in FIG. 8, a core having a larger control magnetic flux density ΔB due to a smaller control magnetizing force H has a larger amplification degree and shows a characteristic superior to a saturable magnetic core. (For CMC, see Koichi Murakami, “Magnetic Applied Engineering,” Asakura Shoten.) On the other hand, as a method for evaluating core loss, the present applicant has previously disclosed in Japanese Patent Application No. 62-237966, A method for defining and measuring the flux change rate was proposed. In this method, for example, the core loss measured using the circuit of FIG. 9 is calculated by using the magnetic flux change rate (dB / dt) gate during the gate period obtained from the waveforms of the respective parts of FIG. 10 as shown in FIG. Loss can be specified.

Note that the magnetic flux change rate during the gate period can be obtained by equation (3) if the waveform v7 at Tb is a rectangular wave as shown in FIG.

[Problems to be Solved by the Invention] The method of measuring AC magnetic characteristics at the time of a minor loop operation including a saturation region according to the related art has the following problems. In the CMC, the reset condition as shown in FIG. 12, ie, when the on-duty ratio D = Ton / Tp is different as shown in FIG. The characteristics in the case where the reset amount is changed by changing the pulse width when the pulse width is changed cannot be directly explained. One example is shown in FIG.
This example shows the reset characteristics when the on-duty ratio D is changed and
This is a comparison of CMC, and can be seen from the fact that the reset characteristics when D = 0.3 and 0.7 are significantly different from those of CMC.

On the other hand, the method of evaluating the core loss by specifying the (dB / dt) gate at the time of the gate is as follows. Under the conditions shown in FIG. 14, (dB / dt) reset is smaller than (dB / dt) gate. As shown in Fig. 15, the core loss can be reduced to (dB / dt) g
I could not explain directly from ate alone.

[Means for Solving the Problems] In order to improve the above-mentioned drawbacks of the prior art, the present invention provides a method for measuring the AC magnetic characteristics of a magnetic core in the operation of a magnetic amplifier, together with a magnetic flux change rate (dB / dt) gate during a gate period. ,
This is an AC magnetic characteristic measuring method that defines a magnetic flux change rate (dB / dt) reset during a reset period and enables measurement of AC magnetic characteristics that can be directly used for designing an actual saturable reactor. Note that the measurement method of the present invention is a conventional CMC and the measurement is performed by defining the dB / dt of the gate period in Japanese Patent Application No. 62-237966.
The present invention relates to the improvement of the measurement method described in the item (1).

[Examples] Hereinafter, the present invention will be described in detail with reference to examples. FIG. 1 shows the configuration of a measuring circuit showing one embodiment of the method for measuring AC magnetic characteristics according to the present invention. This circuit has a power supply 21, a variable resistor 20,
The control circuit includes a main switch 18, a gate circuit including the excitation winding 6 of the sample 2, a power supply 10, and a switch 19. The A / D conversion is performed on the winding end voltage vs of the sample 2 and the exciting current measured by the current detector 8 to perform an arithmetic process.
Calculation of core loss etc. is performed.

Here, the voltage vg of the power supply 21 and the variable resistor 2 for defining the magnetic flux change speed at the time of the gate and the maximum saturation magnetization H _L m are defined.
Set the resistance value _{RL of} 0 as follows.

N _L : Number of turns of the main winding Further, in the present invention, the control voltage vc and the reset period Tr are newly set by the equation (6) in order to define the magnetic flux change speed during the reset period.

vc: control voltage (V) Tr: reset period (s) According to equation (6), if (dB / dt) reset is determined, control voltage
vc can be determined, and the reset period Tr and the magnetic flux change amount ΔBc
The relationship with m is determined. Generally, the core loss is the flux change rate dB /
depends on dt but different flux rate of change in the case where the gate period and the reset period of the magnetic amplifier, for further depends on the maximum saturation magnetizing force H _L m at gate, it is necessary to determine independently respectively. In order to measure the magnetic core loss by defining the magnetic flux change rate in the reset period together with the gate period, as shown in FIG. 2, the core loss is determined in the gate period (the region where the magnetizing force is positive) and the reset period. (Magnetizing force H
Is a negative region. It is effective to separate and measure the two values in ()).

FIGS. 3 and 4 show the dependence of the core loss during the gate period and the core loss during the reset period on the rate of change in magnetic flux measured using the above method according to the present invention.
H _L m = 80 A / m constant. Comparing the two, the core loss during the gate period is larger for the same flux change speed, but when (dB / dt) reset is larger than (dB / dt) gate, the core loss during the reset period is larger. Is not negligible for the core loss during the gate period, and as described in the above-mentioned problem of the related art, it is found that there is a problem in defining the (dB / dt) gate alone and measuring the core loss.

Tables 1 to 6 show the drive frequency, on-duty ratio, and magnetic core loss measured using this method, and Fig. 12B).
Table 1 shows the effect of the ratio Tr / Toff of the reset period on the off period Toff of the main switch shown in Table 1.
Tables 5 and 5 show the core loss during the gate period, and Tables 2 and 4
Tables and Table 6 show the core loss during the reset period. In each case, it can be seen that if the magnetic flux change speed is the same, the value shows a substantially constant value.

FIG. 5 shows the results of measurement of the reset characteristic of the magnetic core, that is, the amplification degree of the magnetic core, using the present invention. Indicates that the width is high. Tables 7, 8, and 9 show the relationship between the reset characteristics measured using this method, the drive frequency, the on-duty ratio, and the ratio Tr / Toff of the reset period Tr in the off period Toff of the main switch. The effect was examined, and it can be seen that the experimental value and the value read from the curve in FIG.

In the above description, the description has been given of the H _L m = 80A / m constant, even with different values of H _L m, is possible to obtain the same result if only the value of H _L m of the measuring constant it can.

[Effects of the Invention] As is clear from the above description, according to the present invention,
Conventional CMC, or precise amplification in the magnetic amplifier operation of the magnetic core, which was not possible with the measurement method proposed in Japanese Patent Application No. 62-237966, in which measurement is performed by specifying the dB / dt of the gate period, and The core loss can be evaluated, and a saturable reactor for a magnetic amplifier, a saturable reactor for surge absorption, a saturable reactor for a magnetic switch of a high-voltage pulse generator, and the like, for which a clear design method has not been established in the past. The effect is great, for example, it can be applied to the design of a reactor that performs an operation including a saturation region.

[Brief description of the drawings]

FIG. 1 is a block diagram of a method for measuring core loss according to the present invention, and FIG.
The figure is a diagram of the operation BH curve measured according to FIG. 1, FIG. 3 is a diagram showing the core loss during the gate period measured according to FIG. 1, and FIG. 4 is the core loss during the reset period measured according to FIG. , FIG. 5 is a diagram showing reset characteristics, FIG. 6 is a circuit diagram of a control magnetization characteristic measurement circuit, FIG. 7 is a diagram showing operation waveforms of each part in FIG. 6, and FIG. 8 is a measurement result according to FIG. , FIG. 9 is a circuit diagram of a magnetic core loss measuring circuit, FIG. 10 is a diagram showing operation waveforms of each part of FIG. 9, FIG. 11 is a diagram showing measurement results according to FIG. 9, and FIG. Diagram showing waveform examples, thirteenth
The figure shows the on-duty ratio dependence of the control magnetization characteristics.
FIG. 14 is a diagram showing a waveform example of a reset voltage, and FIG. 15 is a diagram showing a measurement example according to a conventional measurement method.

Claims (3)

(57) [Claims] An AC magnetic characteristic measuring method for measuring a core loss when a measured core used for a supersaturated reactor operates on an asymmetric minor loop including a saturation region, wherein the measured core is excited by a rectangular wave voltage. together, magnetizing force has a magnetizing force gate period is a positive region and a reset period is a negative region, the magnetic flux change speed (dB / dt) of the measured magnetic core of the gate period the measured against _gate Core loss of core (However, (dB / dt) _gate = ΔBcm / Tb,
ΔBcm is the operating magnetic flux density, Tb is the width of the voltage pulse induced in the winding wound around the measured core during the gate period), and the rate of change of the magnetic flux of the measured core during the reset period (dB)
/ dt) Core loss of the measured core with respect to _reset (however, (dB / dt) _reset = ΔBcm / Tr, ΔBcm is the operating magnetic flux density, and Tr is the winding wound around the measured core during the reset period. A method of measuring AC magnetic characteristics, comprising: calculating a core loss of the measured core during an asymmetric minor loop operation including a saturation region, based on the total sum of voltage pulses induced in the magnetic field. 2. An AC magnetic characteristic measuring method for measuring the degree of amplification when a core to be measured used in a supersaturated reactor operates on a minor loop including a saturation region, wherein the excitation of the core to be measured is performed by a rectangular wave voltage. A gate period in which the magnetizing force is in a positive region and a reset period in which the magnetizing force is in a negative region, wherein the magnetic flux change rate ((dB / dt) _reset of the core under measurement during the reset period is measured with respect to _reset . Magnetizing force H of the magnetic core (However, (dB / dt) _reset = ΔBcm / Tr, ΔBcm is the operating magnetic flux density, and Tr is the width of the voltage pulse induced in the winding wound around the measured core during the reset period. A) measuring the amplification degree of the magnetic core to be measured. 3. The method according to claim 1, wherein when the magnetic flux change rate is determined, the maximum saturation magnetizing force (H _L m) is determined. A method for measuring AC magnetic characteristics, characterized by being constant.