SU789927A1

SU789927A1 - Ferroprobe magnetometer

Info

Publication number: SU789927A1
Application number: SU772437551A
Authority: SU
Inventors: Ризван Салех Бабаев; Валентин Васильевич Голованов; Александр Георгиевич Сметанин; Борис Анатольевич Шамурин
Original assignee: Предприятие П/Я Г-4444
Priority date: 1977-01-07
Filing date: 1977-01-07
Publication date: 1980-12-23

Description

Изобретение относится к магнитным измерениям с использованием феррозондов с выходом на основной частоте и может найти применение в качестве средства измерения преимущественно слабого постоянного или медленно меняющегося магнитного поля при геофизических и навигационных'измерениях, в частности для целей ориентации подвижных объектов.The invention relates to magnetic measurements using fluxgates with an output at the fundamental frequency and can find application as a means of measuring a predominantly weak constant or slowly changing magnetic field in geophysical and navigation measurements, in particular for the orientation of moving objects.

Известен магнитометр, содержащий феррозонд, источник прямоугольного тока в цепи возбуждения феррозонда и интегратор в цепи сигнальной обмотки, а также регулятор (переменный резистор) и измеритель тока, подключенные между источником прямоугольного тока и обмоткой возбуждения, усилитель, пороговый блок и регистратор, последовательно включенные после интегратора [1].A known magnetometer containing a flux gate, a rectangular current source in the excitation circuit of the flux gate and an integrator in the signal winding circuit, as well as a regulator (variable resistor) and a current meter connected between the rectangular current source and the excitation winding, an amplifier, a threshold block, and a recorder connected in series after integrator [1].

СЦнако данное устройство пригодно для точных измерений только в диапазоне сильных полей.However, this device is suitable for accurate measurements only in the range of strong fields.

ί·Λ ·»·- —....ί · Λ · »· - —....

_ !· .· (_! ·. · (

точМАГНИТОМЕТР f““ ί fpoint MAGNETOMETER f ““ ί f

Цель изобретения - повышение ности измерения слабых полей.The purpose of the invention is to increase the measurement of weak fields.

Указанная цель достигается тем, что феррозондовый магнитометр, содержащий феррозонд, источник прямоугольного тока, 5 подключённый, к обмотке возбуждения, и интегратор, подключенный к сигнальной обмотке, снабжен также источником постоянного тока, а феррозонд выполнен на кольцевом сердечнике и снабжен обмоткой подмагничивания, соединенной с источником постоянного тока, причем обмотка подмагничивания равномерно распределена по сердечнику, сигнальная обмотка расположена на участке сердеч¹⁵ ника по оси.чувствительности феррозонда, а обмотка возбуждения охватывает тело сердечника в плоскости, перпендикулярной оси чувствительности.This goal is achieved by the fact that a flux-gate magnetometer containing a flux-gate, a rectangular current source 5 connected to an excitation winding, and an integrator connected to a signal winding is also equipped with a direct current source, and the flux-gate is made on an annular core and equipped with a magnetization winding connected to a constant current source, wherein the bias winding is evenly distributed along the core, the signal winding is arranged in the area of the nick ¹⁵ serdech osi.chuvstvitelnosti ferroprobe and obmo Single excitation covers the core body in a plane perpendicular to the sensitivity axis.

Кроме того, сигнальная обмотка и обмотка возбуждения выполнены на магнитных каркасах, подвижных в плоскости сердечника относительно его геометрического центра.In addition, the signal winding and the excitation winding are made on magnetic frames moving in the plane of the core relative to its geometric center.

На фиг. 1 приведена электрическая схема магнитометра, а также показано взаимное расположение обмоток феррозонда на кольцевом сердечнике; на фиг. 2 - направление действия магнит- ₅ных потоков в кольцевом сердечнике; на фиг. 3 - основные кривые, поясняющие принцип перемагничивания сердечника вспомогательными полями.In FIG. 1 shows the electrical circuit of the magnetometer, and also shows the relative position of the windings of the flux gate on the ring core; in FIG. 2 - ₅ the direction of action of the magnetic fluxes in the annular core; in FIG. 3 - main curves explaining the principle of magnetization reversal of the core by auxiliary fields.

Магнитометр включает феррозонд на кольцевом сердечнике 1 с входа 2 для подключения источника постоянного тока подмагничивания и входа 3 для подключения источника прямоугольного тока ₁₅ возбуждения, интегратор 4, выполненный по наиболее распространенной схеме усилителя с частотно-зависимой обратной связью и подключенный входом к сигнальному выходу 5 феррозонда. Вы- ₂₀ход 6 интегратора является выходом магнитометра. На фиг. 1 показаны также временная диаграмма 7 тока на входе 3 и временная диаграмма 8 ЭДС на выходе 6 магнитометра. На фиг. 2, поясняющей ₂₅работу феррозонда в составе магнитометра, показаны сердечники 1 с осью а-а чувствительности,' совпадающей с осью обмотки возбуждения и направления действия потоков Фо~ измеряемого, ф_а- воз- ₃θ буждения и Ф_п- подмагничивания. Потоки Ф_р и Ф_ь распределяются по противолежащим участкам 9 и 10 сердечника 1, как по параллельным магнитным цепям. Поток Ф_л подмагничивания действует по замкнутому магнитному контуру сердечника. Так как при измерении слабых магнитных полей обычно справедливо соотйдшение Ф_О<^<Ф_&, то магнитное состояние материала сердечника определяется действием потоков Ф^ и Ф_л. Если в выбранный момент времени направление потоков Ф& и Ф_п в участке 9 совпадает, то в тот же момент времени в участке 10 оно встречное, следствием чего является различное магнитное состояние материала данных участков.The magnetometer includes a flux gate on an annular core 1 from input 2 for connecting a DC bias source and input 3 for connecting a rectangular excitation current source ₁₅ , an integrator 4 made according to the most common amplifier circuit with frequency-dependent feedback and connected to an output signal 5 of a flux gate . The output _{20 of} the integrator 6 is the output of the magnetometer. In FIG. 1 also shows a timing diagram 7 of the current at input 3 and a timing diagram 8 of the EMF at the output 6 of the magnetometer. In FIG. 2, which illustrates _{25 the} operation of the fluxgate as part of a magnetometer, cores 1 are shown with the axis aa of the sensitivity coinciding with the axis of the field coil and the direction of action of the fluxes Ф0 ~ measured, ф _а - excitation ₃ θ, and Ф _п - magnetization. The streams _{f p} and _f _{b are} distributed in opposite sections 9 and 10 of the core 1, as in parallel magnetic circuits. The bias flux _{л l} acts on a closed magnetic core loop. Since when measuring weak magnetic fields is usually fairly sootydshenie F _O ^<<F _k, then the magnetic state of the core material by the action of streams F and F ^ _L. If at the selected moment in time the direction of the fluxes Φ & and Φ _p in section 9 coincides, then at the same moment in time in section 10 it is opposite, resulting in a different magnetic state of the material of these sections.

На фиг. 3 приведена .кривая! зависимости проницаемости μ материала сердечника от индукции В магнитного поля, а также показаны временные диаграммы изменения индукции поля возбуждения* в участках 9 и 10 сердечника 1, смещенные относительно временной оси на величину поля подмагничивания с индукцией ♦В_п, и результирующие временные диаграммы проницаемости /ц ^и Л*2_ материала участков 9 и 10. Последние, с учетом принятых на фиг. 3 обозначений, могут быть записаны в виде х( + уIn FIG. 3 shows the curve! the dependence of the permeability μ of the core material on the magnetic field induction B, and also shows the time diagrams of the change in the induction field induction * in sections 9 and 10 of the core 1, shifted relative to the time axis by the magnitude of the magnetization field with induction ♦ V _p , and the resulting time diagrams of permeability / c ^and L * 2_ of the material of sections 9 and 10. The latter, taking into account those adopted in FIG. 3 notation can be written as x (+ y

Af/«b/⁴ *^{( +} ) где Х( ♦) - единичная, знакопеременная во времени функция £1.Af / «b / ⁴ * ⁽⁺ ) where X (♦) is the unit function, alternating in time, £ 1.

При таком законе изменения проницаемостей материала участков 9 и 10 сердечника 1, магнитная проводимость материала сердечника по замкнутому контуру (для потока ф подмагничивания) равно как и магнитная проводимость тела сердечника в направлении оси а-а (для потоков Ф_й возбуждения и Ф_о измеряемого) остаются неизменными в любом из полупериодов возбуждения (для любого значения функции X (·*·)).With this law of variation of permeability material portions 9 and 10 of the core 1, the magnetic conductivity of the core material in a closed loop (for flow f bias) as well as the magnetic core bodies conductivity in the direction of axis a-a (for streams F _th excitation and F _of the measured) remain unchanged in any of the half-periods of excitation (for any value of the function X (· * ·)).

Сцнако распределение потоков Ф_е и Ф_& по участкам 9 и 10 сердечника 1, как по параллельным магнитным полям, неодинаково для любого из моментов времени, а определяется соотношением магнитных проводимостей материала данных участков.However, the distribution of the fluxes Ф _е and Ф _& over the sections 9 and 10 of the core 1, as for parallel magnetic fields, is not the same for any of the time instants, but is determined by the ratio of the magnetic conductivities of the material of these sections.

Нетрудно также убедиться, что под действием знакопеременного потока <*В возбуждения в сердечнике образуется постоянный размагничивающий кольцевой поток, направленный навстречу потоку Ф^ подмагничивания, что несущественно отражается на работе феррозонда и магнитометра (этот поток действует по закону К²(%)=1 и постоянен ввиду постоянства во времени данной функции). Напротив, под действием постоянного изме ряемого магнитного потока Ф, в замкнутой магнитной цепи сердечника появляется знакопеременный поток Ф видаIt is also easy to verify that under the action of an alternating flux <* B the excitation in the core forms a constant demagnetizing ring flow directed towards the magnetization flux Ф ^, which insignificantly affects the operation of the flux probe and magnetometer (this flux acts according to the law K ² (%) = 1 and constant due to the constancy in time of this function). On the contrary, under the action of a constant measurable magnetic flux Ф, an alternating flux Ф of the form appears in a closed magnetic circuit of the core

л. л. л-Л·l l l-l

Этот по ток вы является в вид еЭДСе .наводимой на выводах 5 сигнальной обмотки _е -V/φ · —---—— ,This flow is in the form of an emf. Induced at the terminals 5 of the signal winding _e -V / φ · —---——,

I at ° A*oI at ° A * o

Где W число витков сигнальной обмотки.Where W is the number of turns of the signal winding.

Последующее интегрирование ЭДС е^ посредством интегратора 4 позволяет устранить частотные искажения данного сигнала из-за дифференциального вида закона электромагнитной индукции e₂-'-Kje (+)dt--kwa>_o· о “о где - ЭДС на выходе интегратора, а К - его постоянная.Subsequent integration of the EMF e ^ through integrator 4 allows us to eliminate the frequency distortions of this signal due to the differential form of the law of electromagnetic induction e ₂ -'- Kje (+) dt - kwa> _o · о “where is the EMF at the output of the integrator, and K - its constant.

Таким образом, выходная ЭДС магнитометра изменяется также по прямоугольному во времени закону, а ее амплиту да и фаза (полярность) определяются величиной и направлением измеряемого поля. ЭДС е^ легко преобразовать при необходимости в постоянное напряжение с величиной и знаком, соответствующими величине и направлению измеряемого по' ля, известными средствами, например с помощью синхронного детектора, управляемого непосредственно источником тока возбуждения.Thus, the output EMF of the magnetometer also changes according to a law that is rectangular in time, and its amplitude and phase (polarity) are determined by the magnitude and direction of the measured field. EMF e ^ is easily converted, if necessary, into a constant voltage with a magnitude and sign corresponding to the magnitude and direction of the measured field, by known means, for example, using a synchronous detector controlled directly by the excitation current source.

Поставленная цель (высокая точность измерения слабого магнитного поля) достигается лишь при конкретном исполнении обмоток феррозонда. Обмотка под-“ магничивания 2 должна быть равномерно распределена по кольцевому сердечнику 1, чем исключается появление на сердечнике полюсов намагничивания. Электромагнитная развязка цепей возбуждения и сигнальной обеспечивается лишь при ортогональном расположении плоскостей соответствующих обмоток. Оцнако для достижения качественной развязки упомянутых цепей, с учетом возможных магнитных аномалий свойств материала по' контуру сердечника, целесообразно размещение обмоток возбуждения и сигнальной на подвижных каркасах.. Регулировкой положения данных каркасов по отношению к сердечнику (поворотом сердечника) и друг другу достигается Нулевой сигнал на выходе магнитометра при нулевом измеряемом поле.The goal (high accuracy of measuring a weak magnetic field) is achieved only with a specific design of the flux-gate windings. The magnetization winding 2 must be evenly distributed over the annular core 1, which excludes the appearance of magnetization poles on the core. Electromagnetic isolation of the excitation and signal circuits is provided only with the orthogonal arrangement of the planes of the corresponding windings. However, in order to achieve a high-quality isolation of the mentioned circuits, taking into account possible magnetic anomalies of the material properties along the core contour, it is advisable to place the excitation and signal windings on the movable frames. By adjusting the position of these frames in relation to the core (by turning the core) and to each other, a Zero signal magnetometer output at zero measured field.

Устройство обеспечивает точное измерение слабых полей, что достигается видоизмененным размещением обмоток возбуждения и сигнальной на кольцевом сердечнике, введением обмотки подмагничивания и нового (источник постоянного тока) структурногоThe device provides an accurate measurement of weak fields, which is achieved by the modified placement of the field windings and the signal coil on the ring core, the introduction of the magnetization winding and a new (direct current source) structural

R 33/02, 1977.R 33/02, 1977.

tt

t t

Размещением обмоток сигнальной и возбуждения па подвижных каркасах достигается необходимая для точных измерений электромагнитная развязка входной ной) (возбуждения)' и выходной (сигнальцепей феррозонда.By placing the signal and excitation windings on the moving frames, the electromagnetic isolation of input input (excitation) 'and output (signal circuits of the flux-gate) necessary for accurate measurements is achieved.

рмула изобретенияrmula of the invention

Claims

The invention relates to magnetic measurements using flux-probes with an output at the fundamental frequency and can be used as a means of measuring mainly weak constant or slowly varying from a magnetic field in geophysical and navigation measurements, in particular for the purposes of orientation of moving objects. A magnetometer containing a flux probe, a rectangular current source in the flux-field excitation circuit and an integrator in the signal winding circuit, as well as a regulator (variable resistor) and a current meter connected between the rectangular current source and the excitation winding, amplifier, threshold unit and recorder, are known sequentially included after integrator ij. QlHaKo this device is suitable for accurate measurements only in the range of strong fields. The purpose of the invention is improving the accuracy of measuring weak fields. This goal is achieved by the fact that a fluxgate magnetometer containing a flux probe, a rectangular current source connected to the field winding, and an integrator connected to the signal winding is also provided with a DC source, and the ferrozd is made on an annular core and provided with a secondary winding connected with a DC source, the bias winding being evenly distributed over the core, the signal winding is located on the section with the daughter along the axis of sensitivity of the fluxgate, and the winding excitation covers the core body in a plane perpendicular to the axis of sensitivity. In addition, the signal winding and the excitation winding are made on magnetic frames, which are movable in the plane of the core relative to its geometric center. FIG. 1 shows the electrical circuit of the magnetometer, and also shows the relative position of the windings of the fluxgate on the ring core; on . 2 shows the direction of the magnetic flux in the ring core; in fig. 3 - main curves, according to the principle of magnetic reversal of the core by auxiliary fields. The magnetometer includes a ferrosonde on an annular core 1 from input 2 for connecting a DC bias source and input 3 for connecting a source of a rectangular excitation current, integrator 4, made using the most common amplifier with frequency-dependent feedback and connected to the signal output 5 ferrosonde. Output 6 of the integrator is the output of the magnetometer. FIG. 1 shows also a time diagram 7 of the current at the input 3 and a time diagram 8 of the EMF at the output 6 of the magnetometer. FIG. 2, showing the operation of the fluxgate in the composition of the magnetometer, shows the cores 1 with the axis aaa of the sensitivity, coinciding with the axis of the excitation winding and the direction of the action of the Phased, arcing and Fc-magnetizing. The fluxes F. and F are distributed along the opposing sections 9 and 10 of the core 1 as along parallel magnetic circuits. The flux „bias acts along the closed magnetic contour of the core. Since, when measuring weak magnetic fields, correlation is required. This magnetic state of the core material is determined by the action of the flux Fr. and F. If at the selected time instant the direction of the fluxes Fj and F in section 9 coincides, then at the same time point in section 1O it is opposite, resulting in a different magnetic state of the material of these sections. FIG. 3 gfeivedena; the dependence of the permeability of the core material on the induction of the B magnetic field, and also shows the time diagrams of the induction field induction change in sections 9 and 1 of the core 1, shifted relative to the time axis by the magnitude of the bias field with the induction tBf |, and the resulting time diagrams of the permeability ju and. material sections 9 and 10. The latter, taking into account those adopted in FIG. 3 designations can be written in the form + / JX (f). () Where X () is single, sign-variable function in time 41. With this law of change in the permeabilities of the material of sections 9 and Yu of core 1, the magnetic conductivity of the material of the core to a closed loop (for the bias flux flux), as well as the magnetic conductivity of the core body in the direction of the a-a axis (for excitation fluxes Fz and measured Fd), remain unchanged in any of the excitation half-periods (for any value of the X () function). However, the distribution of flux Φ and Φr over sections 9 and 10 of core 1, as in parallel magnetic fields, is not the same for any of the points in time, but is determined by the ratio of the magnetic conductivities of the material of these areas. It is also not difficult to be convinced that under the action of the alternating flux g of excitation in the core a permanent demagnetizing ring flux is formed, directed towards the flux FM magnetization, which is negligible in the operation of the ferrozond and magnetometer (this flux acts according to the law Φ (fc) l and is significant time function of this function). On the contrary, under the action of a constant measurable magnetic flux Φ, an alternating flux в Fcc appears in the zak tine magnetic core circuit. . () This flux is detected in the form of an emf e, induced at the terminals of the 5th signal winding): -dt-- o7 -Bt where the number of turns of the signal winding. The subsequent integration of the emf e by means of the integrator 4 allows one to eliminate the frequency distortions of this signal due to the differential form of the electromagnetic induction law e --Kje COdt - KW t)) where 2 is the SDS at the output of the integrator and K is its constant. Thus, the output EMF of a magnetometer also varies according to a law that is rectangular in time, and its amplitude and phase 1) is determined by the magnitude and direction of the measured l. The EMF Q-2 is easily converted, if necessary, into a constant voltage with a magnitude and a sign corresponding to the magnitude and direction of the measured field, by known means, for example, using a synchronous detector controlled directly by the current source. The goal (high accuracy of measuring a weak magnetic field) is achieved only with a specific design of the windings of the fluxgate. The magnetic winding 2 should be evenly distributed over the ringed core 1, thus eliminating the appearance of the magnetization poles on the core. Electromagnetic decoupling of the excitation and signal circuits is provided only when the bones of the corresponding windings are orthogonal to each other. However, to achieve qualitative isolation of the mentioned chains, taking into account possible magnetic anomalies of the material properties along the contour of the core, it is advisable to arrange the excitation windings and signal windings on moving frames. By adjusting the position of these frames relative to the core (by turning the core) and each other, zero is achieved. Signal at the output of the magnetometer at zero measured field. The device provides accurate measurement of weak fields, which is achieved by a modified placement of the excitation and signal windings on the ring core, the introduction of a bias winding and a new (DC source) structural node. 2 2 Place the shells of the windings of the signal; It is necessary to accurately and electrically isolate the input (excitation) - and output (signal) circuits of the fluxgate. Claim 1. A fluxgate magnetometer containing a ferrozove, a source of rectangular current connected to the excitation winding, and an integrator connected to the signal winding, characterized in that, in order to improve the accuracy of measuring weak plumes, it is supplied with a direct current source, and ferrozond is made on an annular core and is provided with a bias winding connected to a DC source, the magnetization winding being evenly distributed over the core, the signal winding is located on the section the core is along the sensitivity axis of the fluxgate, and the excitation winding covers the core body in a plane perpendicular to the axis of sensitivity.

2. A fluxgate magitometer according to ru 1, characterized in that the signal winding and the excitation winding are executed on non-magnetic frames moving in the plane of the core relative to its geometric center. Sources of information that are taken into account during the examination 1. USSR Copyright Certificate No. 525902, cl. G O1 P. 33 / O2, 1977.

WITH(/

OP

FIG. 2