JPH0534426A - Measuring method for magnetism - Google Patents
Measuring method for magnetismInfo
- Publication number
- JPH0534426A JPH0534426A JP27604491A JP27604491A JPH0534426A JP H0534426 A JPH0534426 A JP H0534426A JP 27604491 A JP27604491 A JP 27604491A JP 27604491 A JP27604491 A JP 27604491A JP H0534426 A JPH0534426 A JP H0534426A
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- coil
- output
- output voltage
- magnetic flux
- measurement method
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は微小な磁束密度に対して
線形出力で高出力電圧を得ることのできる磁気センサに
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor capable of obtaining a high output voltage with a linear output for a minute magnetic flux density.
【０００２】[0002]
【従来の技術】磁気を計測する方法とし一般に公知な方
法としては、ホール素子，マグネットダイオード，
磁気抵抗素子，可飽和型センサ等がある。2. Description of the Related Art Generally known methods for measuring magnetism include Hall element, magnet diode,
There are magnetoresistive elements and saturable sensors.
【０００３】第７図は可飽和型センサの動作原理を示す
ブロック図である。６は発振器、Ａ，Ｂは強磁性体コ
ア、Ｃ１，Ｃ２は強磁性体を磁化するための１対の１次
コイル、Ｓ１，Ｓ２は１対のサーチコイル、７は差動増
幅器、８はオシロスコープFIG. 7 is a block diagram showing the operating principle of the saturable sensor. 6 is an oscillator, A and B are ferromagnetic cores, C 1 and C 2 are a pair of primary coils for magnetizing the ferromagnetic material, S 1 and S 2 are a pair of search coils, and 7 is differential. Amplifier, 8 is an oscilloscope
【０００４】第８図は第７図において外部から共通磁束
が交差したときに得られるパルス磁束の説明例で以下図
７を用いて従来技術を簡単に説明する。FIG. 8 shows an example of the pulse magnetic flux obtained when the common magnetic flux from the outside crosses in FIG. 7, and the prior art will be briefly described below with reference to FIG.
【０００５】可飽和型磁気センサは、一定方向の定状磁
界中で強磁性体の履歴曲線が非対称になることを利用す
る技術である。The saturable magnetic sensor is a technique which utilizes the fact that the hysteresis curve of a ferromagnetic material becomes asymmetric in a constant magnetic field in a fixed direction.
【０００６】図に示すごとく、１対の強磁性体コアＡ，
Ｂに各々Ｃ１，Ｃ２の磁化コイル（コイルの差方は相互
に逆方向）を設置、このコイルに発振器６から交流電流
を供給し、前記した強磁性体コアＡ，Ｂを飽和するまで
磁化する。As shown in the figure, a pair of ferromagnetic cores A,
C 1 and C 2 magnetizing coils are installed in B (the coils differ from each other in opposite directions), and an alternating current is supplied to the coils from the oscillator 6 until the ferromagnetic cores A and B are saturated. Magnetize.
【０００７】この条件下で外部から磁界Ｈが印加される
と、１対の強磁性体コアＡ，Ｂには合成磁界が発生し、
その差分に対応した出力電圧が、１対のサーチコイルＳ
１，Ｓ２に誘起される。When a magnetic field H is applied from the outside under these conditions, a synthetic magnetic field is generated in the pair of ferromagnetic cores A and B,
The output voltage corresponding to the difference is a pair of search coils S
1 and S 2 .
【０００８】この１対の出力電圧を差動増幅器７に加え
て所期値に増幅すると差動増幅器の出力端子には、１対
の強磁性体コアに交差する外部磁界Ｈに対応したパルス
幅変調された出力電圧が得られる。When this pair of output voltages is applied to the differential amplifier 7 and amplified to a desired value, the output terminal of the differential amplifier has a pulse width corresponding to the external magnetic field H intersecting the pair of ferromagnetic cores. A modulated output voltage is obtained.
【０００９】この出力電圧を図示しないがＬ，Ｐ，Ｆ
（ローパスフィルター）で直流電圧に変換し、この出力
電圧を計測することにより間接的に外部磁界を計測する
ことができる。なお可飽和型磁気センサの動作原理の詳
細はセンサ実用便覧（Ｓ５３，１１，１５日発行）発行
先フジテクノシステムを参照されたし。Although not shown, the output voltage is L, P, F.
The external magnetic field can be indirectly measured by converting the DC voltage with a (low-pass filter) and measuring the output voltage. For details of the operating principle of the saturable magnetic sensor, refer to the Fuji Techno System issued by the sensor practical handbook (issued on S53, 11, 15th).
【００１０】[0010]
【発明が解決しようとする課題】従来技術では下記に示
す問題点が存在し、改良技術が強く要望されている。The prior art has the following problems, and an improved technique is strongly demanded.
【００１１】可飽和型磁気センサは、他の方法（ホール
素子、マグネットダイオード、磁気抵抗素子）と比較し
て温度変化特性は良好である。しかし、微小磁束密度に
対する出力電圧の線形特性に欠点がある。図９は従来技
術（図７に示す）の構成で１対の強磁性体コアＡ，Ｂの
一方のみに外部磁界を印加し、このときの出力電圧特性
を記録した結果である。The saturable magnetic sensor has better temperature change characteristics than other methods (Hall element, magnet diode, magnetoresistive element). However, there is a drawback in the linear characteristic of the output voltage with respect to the minute magnetic flux density. FIG. 9 is a result of recording an output voltage characteristic at this time by applying an external magnetic field to only one of the pair of ferromagnetic cores A and B in the configuration of the conventional technique (shown in FIG. 7).
【００１２】図９に示す如く、０〜４Ｇａｕｓｓまでは
磁束密度に対して出力電圧の変化が極端に小さく、磁束
密度に対する直線性がない。As shown in FIG. 9, from 0 to 4 Gauss, the change in output voltage is extremely small with respect to the magnetic flux density, and there is no linearity with respect to the magnetic flux density.
【００１３】従って、従来技術では０，Ｇａｕｓｓ近辺
に対する磁束密度の計測精度は極端に悪化する。Therefore, in the prior art, the measurement accuracy of the magnetic flux density near 0 and Gauss is extremely deteriorated.
【００１４】[0014]
【課題を解決するための手段】本願は、従来技術の欠点
を解決し微小磁束密度に対する検出感度特性を向上さ
せ、０，Ｇａｕｓｓ近辺の直線性を、飛躍的に改善する
ことを目的とした技術である。The present application aims to solve the drawbacks of the prior art, improve the detection sensitivity characteristics for minute magnetic flux density, and dramatically improve the linearity in the vicinity of 0 and Gauss. Is.
【００１５】[0015]
【作用】本願の基本原理構成を第１図に示す。図におい
て１は発振器、２は加算器、３は直流電源、Ｚは直列抵
抗、Ｃは強磁性体コア、Ｓはコイル、４はパルス幅変調
器、５はデテクタ、以下図１を用いて本願技術の基本動
作を説明する。The operation of the basic principle of the present application is shown in FIG. In the figure, 1 is an oscillator, 2 is an adder, 3 is a DC power supply, Z is a series resistance, C is a ferromagnetic core, S is a coil, 4 is a pulse width modulator, 5 is a detector, and the present application will be described below with reference to FIG. The basic operation of the technology will be described.
【００１６】図に示す如く、発振器１から交流電圧Ｖを
発振させ、加算器２に加える。他方加算器には直流電源
３から直流電圧ＶＤＣを加えて加算する。この加算器２
の出力電圧は直列抵抗Ｚを介してコイルＳに印加され、
（１）式で表示される電流をコイルに供給する。
Ｉ＝ＶＤＣ＋Ｖ／（Ｒ＋ＲＯ）＋ＪＸ ・・・（１）As shown in the figure, an AC voltage V is oscillated from an oscillator 1 and added to an adder 2. On the other hand, the DC voltage V DC from the DC power supply 3 is added to the adder and added. This adder 2
Is applied to the coil S through the series resistance Z,
The current represented by the equation (1) is supplied to the coil. I = V DC + V / (R + R O ) + JX (1)
【００１７】（１）式において、ＶＤＣは加算器出力の
直流電圧、Ｖは加算器出力の交流電圧、Ｒは直列抵抗の
値、ＲＯはコイルＳの直流抵抗ＪＸはコイルＳのリアク
タンス、ＩはＩ＝ＩＤＣ＋ｉ、ＩＤＣは直流電流、ｉは
交流電流、前記した強磁性体Ｃには、直流磁界と交流磁
束の合成磁界が交差することになる。このため強磁性体
の磁化特性は図２（ｂ）に示す特性を示す。In the equation (1), VDC is the DC voltage of the adder output, V is the AC voltage of the adder output, R is the value of the series resistance, R O is the DC resistance of the coil S, JX is the reactance of the coil S, I is I = I DC + i, I DC is a direct current, i is an alternating current, and the above-mentioned ferromagnetic material C intersects with a synthetic magnetic field of a direct current magnetic field and an alternating magnetic flux. Therefore, the magnetization characteristics of the ferromagnetic material show the characteristics shown in FIG.
【００１８】この条件下で外部磁界が強磁性体コアＣに
交差すると図２の（ｂ）の磁化特性から外部磁界の強度
に対応して変化することになる。このバイアス磁界（直
流電流をコイルＳに流すことによって発生する磁界）を
加えることにより微小磁束密度に対する検出感度を格段
に向上することができる。Under this condition, when the external magnetic field crosses the ferromagnetic core C, the magnetization characteristics shown in FIG. 2B change depending on the intensity of the external magnetic field. By adding this bias magnetic field (the magnetic field generated by causing a direct current to flow through the coil S), the detection sensitivity for a minute magnetic flux density can be significantly improved.
【００１９】[0019]
【発明の実施例】本願の１実施例を図面を用いて説明す
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.
【００２０】図３において、ＩＣ１は発振器で品名（Ｎ
Ｅ５５５）、Ｔｒ１はトランジスタでエミッタフロアで
動作、Ｒ１はエミッタフロア抵抗、Ｓはセンサのコイ
ル、ＩＣ２はパルス幅変調器（ヒステリシス型コンパレ
ータ）、Ｒ２，Ｒ３はヒステリシス特性を決定する帰還
抵抗、Ｒ４，Ｄは抵抗Ｒ４とコンデンサＤとによるロー
パスフィルター。In FIG. 3, IC 1 is an oscillator and has a product name (N
E555), Tr 1 is a transistor and operates at an emitter floor, R 1 is an emitter floor resistance, S is a coil of a sensor, IC 2 is a pulse width modulator (hysteresis type comparator), and R 2 and R 3 determine hysteresis characteristics. The feedback resistors R 4 and D are low-pass filters formed by the resistor R 4 and the capacitor D.
【００２１】図４は図３の構成による各部の出力電圧波
形である。FIG. 4 is an output voltage waveform of each part having the configuration of FIG.
【００２２】発振器ＩＣ１（ＮＥ５５５等）で三角波と
直流電圧とが合成された出力電圧、図４（Ｃ）を得る。
この合成した出力電圧をエミッタフロア（Ｔｒ１）のベ
ースに結線し、エミッタに抵抗Ｒ１と磁気センサのコイ
ルＳ’を結線し、コイルの１端を電源のアースに結線す
る。次に、コイルに得られる出力電圧、図４（ｄ）をヒ
ステリシス型コンパレータ（ＩＣ２：ＬＭ３１１等）の
反転入力端子に結線する。コンパレータ（ＩＣ２）の出
力から１対の抵抗Ｒ３，Ｒ２とで正帰還回路を構成す
る。An output voltage obtained by synthesizing the triangular wave and the DC voltage by the oscillator IC 1 (NE555 or the like), FIG. 4C is obtained.
The synthesized output voltage is connected to the base of the emitter floor (Tr 1 ), the resistor R 1 and the coil S ′ of the magnetic sensor are connected to the emitter, and one end of the coil is connected to the ground of the power supply. Next, the output voltage obtained in the coil, FIG. 4D, is connected to the inverting input terminal of the hysteresis type comparator (IC 2 : LM311 or the like). The output of the comparator (IC 2 ) and the pair of resistors R 3 and R 2 form a positive feedback circuit.
【００２３】この正帰還回路でコンパレータ（ＩＣ２）
の出力電圧Ｖｏを正帰還率｛Ｒ２／（Ｒ２＋Ｒ３）｝に
より非反転入力端子に帰還する。この正帰還回路の動作
によって、コンパレータ（ＩＣ２）の出力端子には図４
（ｅ）に示すごとく、パルス幅変調された一定振幅の短
形波出力が得られる。With this positive feedback circuit, a comparator (IC 2 )
The output voltage Vo is fed back to the non-inverting input terminal at a positive feedback rate {R 2 / (R 2 + R 3 )}. By the operation of this positive feedback circuit, the output terminal of the comparator (IC 2 ) is
As shown in (e), a pulse width modulated rectangular wave output having a constant amplitude is obtained.
【００２４】この出力電圧を、ローパスフィルター
｛（以下Ｌ．Ｐ．Ｆと記す）抵抗Ｒ４とコンデンサＤと
で構成する｝に加えて直流成分を抽出する。Ｌ．Ｐ．Ｆ
に得られる出力電圧を測定することにより磁気センサを
構成する強磁性体コアに交差する外部磁界を間接的に計
測することが出来る。This output voltage is added to a low pass filter (which is composed of a resistor R 4 and a capacitor D (hereinafter referred to as LPF)) to extract a DC component. L. P. F
The external magnetic field intersecting the ferromagnetic core that constitutes the magnetic sensor can be indirectly measured by measuring the output voltage obtained in the above.
【００２５】図５は、本願技術コアにアモルファスを用
いた磁気センサによる磁束密度に対する出力電圧特性を
示す。図６は、コアにパーマロイを用いた磁気センサに
よる磁束密度に対する出力電圧特性を示す。FIG. 5 shows the output voltage characteristics with respect to the magnetic flux density by the magnetic sensor using the amorphous core of the present technology. FIG. 6 shows output voltage characteristics with respect to magnetic flux density by a magnetic sensor using permalloy as a core.
【００２６】[0026]
【発明の効果】以上説明したように、本発明の磁気計測
法によれば図５に示す如く微小磁束密度に対して検出感
度が高く、かつ、磁束密度対して線形特性が得られる。
また、センサコイルに、直流電流を流す事でコアの磁化
効率を高めることができ、電子回路の小型化、ハイブリ
ット化が容易である。よって構成が極めて簡単で、温度
変化特性の良好な磁気センサが得られる。As described above, according to the magnetic measurement method of the present invention, as shown in FIG. 5, the detection sensitivity is high with respect to the minute magnetic flux density, and the linear characteristic with respect to the magnetic flux density is obtained.
In addition, the magnetizing efficiency of the core can be increased by applying a direct current to the sensor coil, and the electronic circuit can be easily downsized and hybridized. Therefore, it is possible to obtain a magnetic sensor having a very simple structure and a good temperature change characteristic.
【図１】 本願の基本構成図。FIG. 1 is a basic configuration diagram of the present application.
【図２】 強磁性体コアの磁化特性図。FIG. 2 is a magnetization characteristic diagram of a ferromagnetic core.
【図３】 本願技術の１実施例。FIG. 3 is an example of the present technology.
【図４】 本願図３における各回路の出力波形。FIG. 4 is an output waveform of each circuit in FIG. 3 of the present application.
【図５】 本願技術による微小磁束密度に対する出力電
圧特性。FIG. 5 is an output voltage characteristic with respect to a minute magnetic flux density according to the technique of the present application.
【図６】 本願技術による微小磁束密度に対する出力電
圧特性。FIG. 6 is an output voltage characteristic with respect to a minute magnetic flux density according to the technique of the present application.
【図７】 従来技術の説明図。FIG. 7 is an explanatory diagram of a conventional technique.
【図８】 図７で得られるパルスの説明図。8 is an explanatory diagram of pulses obtained in FIG. 7. FIG.
【図９】 従来技術による磁束密度に対する出力電圧特
性。FIG. 9 shows output voltage characteristics with respect to magnetic flux density according to the related art.
１，６，ＩＣ１は発振器、２は加算器、３は直流電源、
Ａ，Ｂ，Ｃは強磁性体コア、Ｚは直列抵抗、Ｓ，Ｓ’は
コイル、４はパルス幅変調器、５はデテクタ、７は差動
増幅器、８はオシロスコープ、Ｃ１，Ｃ２は強磁性体を
磁化するための、一対の一次コイル、Ｓ１，Ｓ２は一対
のサーチコイル、Ｔｒ１はエミッタフロア、ＩＣ２はヒ
システリシス特性型コンパレータ、Ｒ２，Ｒ３は正帰還
用抵抗、Ｒ４，ＤはＬ・Ｐ・Ｆ用抵抗とコンデンサ、
（ａ）はＩＤＣ＝０ｍＡ時、（ｂ）はＩＤＣ＝０ｍＡ
時、（ｃ）は発振器の出力波形、（ｄ）はセンサコイル
Ｓの出力波形、（ｅ）はコンパレーターの出力波形、1, 6, IC 1 is an oscillator, 2 is an adder, 3 is a DC power supply,
A, B and C are ferromagnetic cores, Z is a series resistance, S and S'are coils, 4 is a pulse width modulator, 5 is a detector, 7 is a differential amplifier, 8 is an oscilloscope, and C 1 and C 2 are A pair of primary coils for magnetizing the ferromagnetic material, S 1 and S 2 are a pair of search coils, Tr 1 is an emitter floor, IC 2 is a hysteresis system type comparator, and R 2 and R 3 are resistors for positive feedback. , R 4 and D are resistors and capacitors for L / P / F,
(A) is at I DC = 0 mA, (b) is at I DC = 0 mA
Where (c) is the output waveform of the oscillator, (d) is the output waveform of the sensor coil S, (e) is the output waveform of the comparator,
Claims (3)
交流電流を流し、コイルに得られる電圧をコンパレータ
−に加えてパルス変調波を作り、この出力をデテクター
に加えて直流に変換し、その出力から前記した強磁性体
に交差する磁束を、計測する磁気計測法において、前記
コイルに直流電流を同時に流し微小な磁束に対する検出
感度を向上したことを特長とする磁気計測法。1. An alternating current is made to flow from an oscillator to a coil wound around a ferromagnetic material, a voltage obtained at the coil is applied to a comparator to create a pulse-modulated wave, and this output is applied to a detector to be converted to direct current, In the magnetic measurement method for measuring the magnetic flux intersecting the above-mentioned ferromagnetic substance from the output, a magnetic measurement method characterized in that a direct current is simultaneously applied to the coil to improve the detection sensitivity to a minute magnetic flux.
の出力をエミッタ・フロアの入力に加え、エミッタ抵抗
に直列に前記したコイルを結線した事を特長とする磁気
測定法。2. The magnetic measurement method according to claim 1, wherein the output of the oscillator is applied to the input of the emitter floor, and the coil is connected in series with the emitter resistance.
られる出力をヒステリシス特性を保持したコンパレータ
ーに加えて、前記したコイルの出力をパルス変調波を作
り、この出力をデテクターに加える事を特徴とする磁気
測定法。3. The output obtained from the coil in the above-mentioned magnetic measurement method is added to a comparator having a hysteresis characteristic, the output of the coil is made into a pulse-modulated wave, and this output is added to a detector. Magnetic measurement method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27604491A JPH0534426A (en) | 1991-07-29 | 1991-07-29 | Measuring method for magnetism |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27604491A JPH0534426A (en) | 1991-07-29 | 1991-07-29 | Measuring method for magnetism |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0534426A true JPH0534426A (en) | 1993-02-09 |
Family
ID=17564010
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27604491A Pending JPH0534426A (en) | 1991-07-29 | 1991-07-29 | Measuring method for magnetism |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0534426A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09133742A (en) * | 1995-11-09 | 1997-05-20 | Kagaku Gijutsu Shinko Jigyodan | Magnetic field sensor |
| US6044790A (en) * | 1997-01-31 | 2000-04-04 | Fujikiko Kabushiki Kaisha | Manual operating apparatus for an automatic transmission |
-
1991
- 1991-07-29 JP JP27604491A patent/JPH0534426A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09133742A (en) * | 1995-11-09 | 1997-05-20 | Kagaku Gijutsu Shinko Jigyodan | Magnetic field sensor |
| US6044790A (en) * | 1997-01-31 | 2000-04-04 | Fujikiko Kabushiki Kaisha | Manual operating apparatus for an automatic transmission |
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