JP2011257283A - Method and device for measuring position of current-carrying part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for measuring a position of a current-carrying part, which is capable of accurately measuring a position of a current-carrying part.SOLUTION: In the method for measuring the position of the current-carrying part, which measures the position and shape of the current-carrying part when evaluating an electromagnetic wave leaking through a gap between metallic plates, a high frequency current is caused to flow between the metallic plates, and a potential distribution generated on metallic plate surfaces is obtained by potential difference measurement with a feed point on the metallic plate surfaces as a reference of potential, and the position of the current-carrying part is determined from the potential distribution.

Description

  The present invention relates to the evaluation of electromagnetic wave leakage from an electronic circuit incorporated in an OA / electrical product, and more particularly to a position measuring method and apparatus for a current-carrying part that accurately measures the position of the current-carrying part in the evaluation of electromagnetic wave leakage. It is.

  OA / electrical products are required to shield leakage electromagnetic waves from electronic circuits incorporated in the product. This is because leaked electromagnetic waves may not only cause other OA / electrical products to malfunction, but also may cause electronic devices such as cardiac pacemakers to malfunction and affect people using them. It is.

  The casing of OA / electrical products is often made of a metal such as a steel plate or an aluminum plate. If there is an electromagnetic wave source inside the metal housing, a gap will be created unless the metal plate overlaps the welded part, and electromagnetic waves may leak from here. It becomes a problem. Therefore, a technique for evaluating the strength of the leaked electromagnetic wave based on a mechanism for leaking the electromagnetic wave to the outside of the housing is an important technique for controlling the electromagnetic wave leakage.

  As a technique for evaluating the strength of such leakage electromagnetic waves, there is a technique disclosed in Patent Document 1. This technology measures the position and shape of the current-carrying part, calculates the interval and length of the current-carrying part, and evaluates the strength of the electromagnetic wave, and evaluates the strength of the leaked electromagnetic wave easily and with high accuracy. There is a feature that can be.

JP 2009-58324 A

  In the technique disclosed in Patent Document 1, the energization unit is obtained as follows. That is, as shown in FIG. 1, a plurality of conducting wires 3 are connected to the surface of a metal plate A1, a metal plate B2 is overlapped on the metal plate A1, and a high frequency current from a high frequency power source 4 is applied between the plates. The potential difference of the potential distribution on the surface of the metal plate A1 is measured using an arbitrary lead as a potential reference (hereinafter also referred to as Ground or ground). The potential difference between the conductors is measured by a potential difference measuring device 5 such as an oscilloscope. If necessary, a signal from the conductor is amplified by an amplifier or unnecessary signals are removed by a filter and input to the potential difference measuring device 5. The energization unit is obtained based on the measured potential distribution.

  In the Example shown by patent document 1, as shown in FIG. 2 (condition-1) and FIG. 3 (condition-2), the location where the high dielectric material is pinched | interposed into two places between metal plates differs. The potential distribution on the plate surface when a high frequency of 10 kHz is applied to the system is measured. A portion where the high dielectric material is sandwiched is a capacitor, and in this case, two capacitors are energized portions.

  FIG. 4 shows the potential distribution on the surface of the metal plate A1 under conditions-1 and-2. As shown in this figure, the potential distribution shows a minimum value in the vicinity of each energized portion, and a correspondence is seen between the position of the energized portion and the potential distribution.

  When a high frequency (alternating current) voltage is applied to each of the resistor, the capacitor, and the coil, the current phase changes by 0, + π / 2, and −π / 2, respectively, with respect to the voltage phase. When the current-carrying part is only a capacitor, only a resistor, or only a coil as in the above-described embodiment, the potential distribution measured with an arbitrary point on the surface of the metal plate as a ground corresponds to the position of the current-carrying part.

  However, when a high frequency voltage is applied to a system in which a resistor, a capacitor, and a coil are mixed, for example, a system in which a resistor and a high dielectric (capacitor) are sandwiched between metal plates as shown in FIG. When the potential distribution is measured with an arbitrary point as a ground, there is a problem that the minimum position of the potential distribution does not match the position of the energization unit.

  The present invention has been made in view of these problems of the prior art, and it is an object of the present invention to provide a position measuring method and apparatus for a current-carrying part that can accurately measure the position of the current-carrying part.

  The present inventors have found that the above problem can be solved by devising the position of Ground, and have arrived at the present invention described below.

  [1] A method for measuring a position of a current-carrying unit for measuring an electromagnetic wave leaking through a gap between metal plates, wherein a high-frequency current is passed between the metal plates, and a feeding point on the surface of the metal plate is a potential. A method for measuring the position of a current-carrying part, wherein a potential distribution generated on the surface of a metal plate is obtained by measuring a potential difference as a reference for determining a current-carrying part from the potential distribution.

  [2] In the method for measuring the position of the energization unit according to [1] above, the potential distribution is obtained by connecting a plurality of conductors to the surface of the metal plate, and calculating a potential difference from the conductors with the feeding point as a potential reference. A method for measuring the position of a current-carrying part, which is obtained by measurement.

  [3] The position measuring method of the energization unit according to the above [1] or [2], wherein the position indicating the minimum value of the potential distribution is determined as the energization unit.

  [4] The energization part position measuring method according to any one of [1] to [3], wherein the metal plate is a steel plate.

  [5] A position measurement device for a current-carrying unit that measures the position of a current-carrying part in evaluating electromagnetic waves leaking through a gap between metal plates, a high-frequency power source for passing a high-frequency current between the metal plates, A feeding point to be applied to the metal plate, a conductor for measuring a potential distribution generated on the surface of the metal plate, a potential difference measuring device for measuring a potential difference between the conductors, and a means for determining a current-carrying portion from the measured potential difference , And using the feeding point as a potential reference for potential difference measurement.

  In the present invention, since the feeding point is used as a potential reference for potential difference measurement, accurate potential distribution can be obtained even when current-carrying parts having different phase characteristics are mixed and the amount of change in the phase of the current with respect to the applied voltage is different. Thus, the position and shape of the energization part can be specified easily and with high accuracy.

It is a figure which shows the electric potential distribution measuring method at the time of applying a direct current. It is a figure which shows the position (condition-1) of an electricity supply part (high dielectric material). It is a figure which shows the position (condition-2) of an electricity supply part (high dielectric material). It is a figure which shows the result of the electric potential distribution measurement by a high frequency current. It is a figure which shows the position of an electricity supply part (a high dielectric material and resistance). It is a figure which shows the result of the electric potential distribution measurement by a high frequency current.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to an accompanying drawing. As shown in FIG. 1, when measuring the potential distribution of the metal plate A <b> 1, a point where a conducting wire from a power source is connected to the plate surface is a feeding point 7. When current carrying parts with different phase characteristics are mixed and the amount of change in the phase of the current with respect to the applied voltage is different, measuring the potential distribution on the surface of the metal plate A1 with the feeding point 7 as Ground 6 corresponds to the position of the conducting part. It was found that the obtained potential distribution was obtained.

  FIG. 5 shows an example in which a resistor and a high dielectric (capacitor) are sandwiched between metal plates E and F to form a current-carrying part. With the feeding point 7 in the figure as Ground 6, a high frequency of 0.3 Hz to 10 kHz was applied between the metal plates, and the potential distribution on the metal plate surface was measured. FIG. 6 is a diagram showing the results of potential distribution measurement using the high-frequency current.

  In the current-carrying part composed of resistors, the potential distribution shows a minimum value at both low and high frequencies, and it can be seen that this current-carrying part can be specified. On the other hand, when the frequency of the applied voltage is low, the current-carrying part composed of a capacitor has a high impedance and does not become a current-carrying part, but when the frequency is high, the impedance becomes low and becomes a current-carrying part. As shown in the figure, when the frequency of the applied voltage is 0.3 Hz, the potential of the capacitor portion does not show a minimum value, but it becomes a minimum value as the frequency increases, and it becomes an energized portion.

  If the point other than the feed point is set to Ground, such a potential distribution cannot be obtained, and if the amount of change in the phase of the current with respect to the applied voltage varies depending on the energized part, it corresponds to the energized part if the feed point is set to Ground. It was confirmed that the obtained potential distribution was obtained.

1 Metal plate A
2 Metal plate B
3 Conductor 4 High frequency power supply 5 Potential difference measuring device 6 Ground
7 Feeding point

Claims (5)

A method for measuring the position of a current-carrying part for measuring the position of a current-carrying part in evaluating electromagnetic waves leaking through a gap between metal plates,
A high-frequency current is allowed to flow between the metal plates, and a potential distribution generated on the surface of the metal plate is obtained by measuring a potential difference using a feeding point on the surface of the metal plate as a potential reference, and a current-carrying portion is determined from the potential distribution. Method for measuring the position of the current-carrying part. In the method for measuring the position of the energization unit according to claim 1,
A method for measuring a position of an energization unit, wherein the potential distribution is obtained by connecting a plurality of conductors to the surface of the metal plate and measuring a potential difference from the conductors with the feeding point as a potential reference. In the method of measuring the position of the energization unit according to claim 1 or 2,
A position measuring method for a current-carrying part, wherein a position indicating a minimum value of the potential distribution is determined as a current-carrying part. In the method for measuring the position of the energization unit according to any one of claims 1 to 3,
The metal plate is a steel plate. A position measuring device for a current-carrying part that measures the position of a current-carrying part in evaluating electromagnetic waves leaking through a gap between metal plates,
A high frequency power source for passing a high frequency current between the metal plates;
A feeding point for applying the high-frequency current to the metal plate;
A conductor for measuring the potential distribution generated on the surface of the metal plate;
A potentiometer that measures the potential difference between the conductors;
Means for determining a current-carrying part from the measured potential difference;
With
An apparatus for measuring a position of a current-carrying unit, wherein the feeding point is used as a reference for potential of potential difference measurement.