CN201876534U - Amorphous-wire magneto-impedance sensor - Google Patents
Amorphous-wire magneto-impedance sensor Download PDFInfo
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- CN201876534U CN201876534U CN2010202761748U CN201020276174U CN201876534U CN 201876534 U CN201876534 U CN 201876534U CN 2010202761748 U CN2010202761748 U CN 2010202761748U CN 201020276174 U CN201020276174 U CN 201020276174U CN 201876534 U CN201876534 U CN 201876534U
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Abstract
The utility model provides an amorphous magneto-impedance sensor which comprises an amorphous wire, a signal sampling coil, an exciting circuit and a signal collecting and processing circuit, wherein the signal sampling coil is enwound on the amorphous wire and is used for detecting the information of an external magnetic field; the exciting circuit is used for providing exciting signals to the amorphous wire directly; the signal collecting and processing circuit collects a voltage signal output by the signal sampling coil and processes the signal, thus outputting a direct-current voltage signal, wherein the exciting signal comprises a square wave signal, a sine wave signal, a sawtooth wave signal or an electrical noise signal. As the selectable range of the exciting signal provided by the exciting circuit comprises the pulse signal commonly used in the prior art, and also comprises the square wave signal, the sine wave signal and the sawtooth wave signal, and even comprises the electrical noise signal, the selectable range of the waveform of the exciting signal is widened so that the amorphous-wire magneto-impedance sensor can flexibly adjust or select different exciting signals according to different application situations.
Description
Technical field
The utility model belongs to the weak magnetic measurement technical field, and the utility model relates to a kind of magnetic field sensor, is specifically related to a kind of amorphous wire magnetoimpedance (Magneto Impedance is abbreviated as MI) sensor.
Background technology
Magnetic-field measurement is a major issue in each field of production scientific research.Along with developing rapidly of microelectric technique, need in fields such as national defence, automotive electronics, Robotics, bioengineering, robotization controls that some are miniature or small-sized, high-performance, high sensitivity and the fast magnetic field sensor of response speed detect correlation parameter, for example Magnetic Field, rotating speed, displacement or the like.At present, Chang Gui magnetic field sensor has: Hall effect (Hall) magnetic field sensor, anisotropic magnetoresistance (AMR) magnetic field sensor, giant magnetoresistance (GMR) magnetic field sensor, fluxgate (Fluxgate) sensor or the like.But above-mentioned magnetic field sensor all has certain defective.For example, though Hall effect magnetic field sensor is the magnetic field sensor that is most widely used at present, its output signal changes little, and sensitivity is low, also has certain magnetic direction anisotropy when measuring magnetic field, is applicable to the medium-high magnetic field measurement; The change rate of magnetic reluctance size of anisotropic magnetoresistance (AMR) magnetic field sensor has only 2%-4%, and its magnetic field sensitivity is less than 1%/Oe, the manufacturing equipment complexity; Giant magnetoresistance (GMR) export can obtain higher signal, but its magnetic field sensitivity is still lower though the change rate of magnetic reluctance of sensor can reach more than 80%; Fluxgate sensor is accurate especially to the requirement of coil winding, and signal processing requirement is higher.And the circuit too complex of the sensor, cost is higher.In the application of high requirement, especially in intelligent transportation, the land and water transportation flow monitoring, vehicle and ship type detect, the convoy spacing and the speed of a motor vehicle detect, parking stall and berth detection and guiding etc. are by the variation realization warning of detection disturbance of magnetic field and the occasion of information monitoring, public safety is taken precautions against, the foundation of disguised circumference, aviation, space flight, under the occasions such as navigation field, above-mentioned magnetic field sensor is because detection of magnetic field resolution is low, detection range is near, response speed is slow, volume is big, the power consumption height, temperature stability is poor, directivity is poor, it is loaded down with trivial details to connect up, or it is difficult in maintenance and can not satisfy the requirement of practical application to the Weak magentic-field fast measuring.
Magneto-impedance effect is to find in amorphous wire in 1992.Magneto-impedance effect (Magneto-Impedance is called for short MI) is meant material under the excitation of high frequency exchange current, and AC impedance is vertiginous phenomenon with the variation of externally-applied magnetic field intensity.Utilize the hypersensitivity of magneto-impedance effect, promptly under small changes of magnetic field, will produce very big AC impedance and change, can learn the faint variation of external magnetic field by the impedance variation of detecting material, and then draw required detection information.
The preparation of high precision, high performance sensor will be based on the sensor material of good quality, performance brilliance, and amorphous material is one of little magnetic susceptibility energy best material of finding at present, has advantageous advantage in the application of magneto-impedance sensors.Along with novel soft magnetic material---succeeding in developing of non-crystaline amorphous metal, promoted the great development of magneto-impedance sensors, be microminiature, lightweight, the high performance of the various magneto-impedance sensors condition that provides the foundation.
The principle of work of amorphous wire magneto-impedance sensors is: utilize the magneto-impedance effect of amorphous wire, by amorphous wire being imposed the excitation of certain frequency, make amorphous wire become the carrier that magnetoimpedance changes.When the external magnetic field changed, the magnetoimpedance of amorphous wire also changed thereupon, and the signal sampling coil on amorphous wire induces the correspondent voltage signal immediately.Thus, this voltage signal just with this moment the external magnetic field power formed clear and definite corresponding relation.By measuring this voltage signal, just can measure the strong and weak and big or small of external magnetic field.
But there are many problems in the existing magneto-impedance sensors of amorphous wire magnetoimpedance technology of utilizing at present, for example, uses pulse signal as pumping signal, and there is impact in sort signal to circuit, and noise is big, and optional excitation signal waveforms kind is limited.And, the amorphous wire magneto-impedance sensors of prior art is by applying bias magnetic field to being wrapped in the coil electricity on the amorphous wire to amorphous wire, this bias magnetic field can exert an influence to measuring magnetic field, because this bias magnetic field puts on the axial of amorphous wire, can stop the circumferencial direction magnetization of annular magnetic domain, hinder the raising of magnetic-field measurement sensitivity to a certain extent, weakened the magneto-impedance effect of amorphous wire.In addition, for sampled signal is amplified, can amplifying circuit be set in signal processing circuit usually, this has not only increased the complicacy of circuit and the cost of sensor, and amplification effect is also undesirable.
Summary of the invention
In order to overcome the deficiencies in the prior art, the inventor is according to the amorphous wire magneto-impedance effect, improve the structure of amorphous wire magneto-impedance sensors by employing, improve the motivational techniques of amorphous wire magneto-impedance sensors, design puts on the dc offset voltage circuit on the amorphous wire, design strengthens the antiresonant circuit of useful signal, improve the technological means such as negative-feedback circuit that improve the measure linear degree, invented a kind of simple in structure, detection range is far away, the resolving accuracy height, response fast, volume is small, the temperature stabilization scope is big, low energy consumption, intelligent, wiring is simple, safeguard simple amorphous wire magneto-impedance sensors.
First purpose of the present utility model has provided a kind of amorphous wire magneto-impedance sensors, comprising: amorphous wire; The signal sampling coil is wrapped on the amorphous wire, is used to detect external magnetic field information; Exciting circuit is used for directly providing pumping signal to amorphous wire; With signals collecting and treatment circuit, the voltage signal of acquired signal sampling coil output is also handled it, thus the output dc voltage signal, and wherein, pumping signal comprises square-wave signal, sine wave signal, sawtooth signal or electrical noise signal.Because selection of excitation signal scope that exciting circuit of the present utility model provided is in prior art the normally used pulse signal, also comprise square-wave signal, sine wave signal and sawtooth signal, even also can comprise the electrical noise signal, therefore widened the range of choice of excitation signal waveforms, made amorphous wire magneto-impedance sensors of the present utility model to adjust or to select different pumping signals neatly according to different application scenarios.
And the exciting circuit of this amorphous wire magneto-impedance sensors comprises programmable oscillator, links by second resistance (R2) between programmable oscillator and the amorphous wire.The coil that is wound on the amorphous wire also comprises reversed trickler, an end ground connection of reversed trickler, and the other end connect second inductance (L2) and adjustable resistance (W1) connect with the output terminal of treatment circuit with signals collecting, thereby constitute negative feedback loop jointly.
Second purpose of the present utility model is that this amorphous wire magneto-impedance sensors also comprises the dc offset voltage circuit, directly be connected with amorphous wire, be used for providing dc offset voltage to amorphous wire, thereby strengthen the magnetization in a circumferential direction of annular magnetic domain, make the circumference magnetic permeability increase, and make the sensing of amorphous wire annular magnetic domain reach unanimity.And the dc offset voltage circuit is composed in series by first inductance (L1) and first resistance (R1).
The 3rd purpose of the present utility model is that this amorphous wire magneto-impedance sensors also comprises antiresonant circuit, this antiresonant circuit is made up of electric capacity (C1) and signal sampling coils from parallel connection of coils, not only can select the effective voltage signal, can also amplify selected effective voltage signal.
The amorphous wire magneto-impedance sensors that the utility model provides has simple in structure, detection range is far away, the resolving accuracy height, response fast, volume is small, the temperature stabilization scope is big, low energy consumption, intelligent, wiring is simple, safeguard simple advantage, can be used for intelligent transportation, the land and water transportation flow monitoring, vehicle and ship type detect, the convoy spacing and the speed of a motor vehicle detect, parking stall and berth detection and guiding etc. are by the variation realization warning of detection disturbance of magnetic field and the occasion of information monitoring, public safety is taken precautions against, the foundation of disguised circumference, aviation, space flight, occasions such as navigation field.
Description of drawings
Fig. 1 is the domain structure schematic diagram on amorphous wire surface;
Fig. 2 is the magnetization curve of amorphous wire material;
Fig. 3 is an amorphous wire magneto-impedance effect schematic diagram;
Fig. 4 is the output voltage of amorphous wire magneto-impedance sensors of the present utility model under different excitation signal and the relation of measuring magnetic field;
Fig. 5 is the structured flowchart of an embodiment of amorphous wire magneto-impedance sensors of the present utility model;
Fig. 6 is the structured flowchart of another embodiment of amorphous wire magneto-impedance sensors of the present utility model;
Fig. 7 is the structured flowchart of another embodiment of amorphous wire magneto-impedance sensors of the present utility model;
Fig. 8 is the structured flowchart of the preferred embodiment of amorphous wire magneto-impedance sensors of the present utility model;
Embodiment
Amorphous material is the new material that a kind of structure is different from traditional crystalline material, its structural notable feature is an atomic arrangement shortrange order and long-range is unordered, be amorphous material be that atomic arrangement only has certain order in the scope of the nearest neighbor distance of atom and time nearest neighbor distance, and unordered in the scope beyond the inferior nearest neighbor distance.The atomic arrangement of non-crystalline material can be thought rambling, and always there is crystal grain in traditional crystalline material, has the order of atomic arrangement.The order of atomic arrangement can cause the anisotropy of structure and performance, and the lack of alignment of atom then can cause the isotropy of structure and performance.Simultaneously, because amorphous material does not have defectives such as crystal boundary, also can not produce harmful effect to performance, thus amorphous alloy have many crystal alloy incomparable excellent properties, as excellent magnetism energy, high corrosion stability, wearing quality, high strength, high rigidity etc.
Amorphous material can be divided into bulk amorphous alloy according to its form difference, amorphous wire, amorphous ribbon, amorphous film, non-crystalline flour etc.The difference of form causes it to have different performances and application.Bulk amorphous alloy is generally pursued its higher mechanical property and is used as structured material; Amorphous band then is a kind of form that is produced out the earliest in the amorphous material, has obtained at aspects such as transformer cores etc. to use widely.Amorphous film is meant the very small amorphous material of one dimension on the three dimension scale of material, its thickness is littler than amorphous ribbon, on performance, because the microminiaturization on its size, and usually be nanometer scale, add its amorphous structure, thereby the effect that not only has some nano materials and had, and have good amorphous alloy material performance,, can be used for making multiple sensors as MI effect etc.Because the difference of magnetic structure, make amorphous alloy material existing similarity when utilizing the MI effect of thread, band shape and film like, but the part that also is very different.
The amorphous material of magneto-impedance sensors of the present utility model adopts the reason of amorphous wire to be, the application of amorphous wire on magneto-impedance sensors has advantageous advantage, the magneto-impedance effect that amorphous film had (MI) also exists in amorphous wire, utilizes amorphous wire to prepare magneto-impedance sensors and can realize advantages such as highly sensitive, that size is small, response speed is fast equally.The isotropy of amorphous wire and do not exist the feature of defectives such as crystal boundary to make it aspect magnetic property, have very high magnetic permeability, very low coercive force and loss, good high frequency performance etc., can do electronic transformer, magnetic head, sensor etc., especially Co base amorphous wire material is one of the most excellent soft magnetic material that it is found that up to now and magneto-impedance effect material.The thread spatial structure of amorphous wire, very responsive to axial external magnetic field, insensitive to the external magnetic field of other directions, have good detection direction.
The physical principle that amorphous wire is used for the MI magneto-impedance sensors is, amorphous wire material is because the isotropy of its non crystalline structure, there is not the structural unevenness that domain wall motion is caused resistance, do not exist meetings such as crystal boundary that magnetic is caused dysgenic various defective, and magnetostriction coefficient λ
SLevel off to zero (λ
S=-1 * 10
-7), therefore have good soft magnet performance, have less coercive force, bigger magnetic permeability.Because there is different cooldown rates on the surface of amorphous wire silk in the chilling preparation process with the center, superficial layer is subjected to the force of compression of circumferencial direction (or axial), and the central area is subjected to is tension force, because magnetostrictive effect causes the circumference magnetic anisotropy, make the superficial layer magnetic moment along the circumferential direction or axial array, and the demagnetization field energy makes magnetic moment select arrangement mode along the circumferential direction, the center of silk and the different domain structure of outer formation, thereby the surface of silk has the anisotropy of circumferencial direction, formation ring-type magnetic domain.The magnetization direction of central area is axial along filament, its domain structure such as thick bamboo tube shape.When passing to alternating current in the amorphous wire, because skin effect, electric charge will be pressed close to the skin conduction of silk, and outer field circumferential easy magnetization performance plays decisive influence to its magnetosensitive sense, produces circumferential alternating magnetic field H around silk
θ, outer magnetic domain is at H
θBe easy to by domain wall motion generation circumferential magnetization process under the effect.Formed the domain structure of ring shape on the surface of silk, as shown in Figure 1, the outer direction of easy axis of this structure is circumferentially, and is left-handed and dextrorotation replaces, and the core direction of easy axis is axial.If apply external magnetic field Hex along the silk axial direction again, then magnetic domain will be at H
θActing in conjunction motion down with Hex.Because the intensity of Hex is less, and silk axially is hard direction, so can not make the resistivity generation significant change of silk, but the faint axial external magnetic field that applies has very big influence to the circumferential magnetization process of silk, significantly changed the value of circumference magnetic permeability, and on the AC impedance value of conductor, reflect, thereby cause the generation of MI effect.Fig. 2 is the magnetization curve of amorphous wire material, and wherein M represents the magnetization of amorphous wire, and H represents external magnetic field.
The theoretical formula of MI effect is described below in the amorphous wire: the source of MI effect is closely-related with the skin effect of material under exchange current excites.For filar conductors, its impedance can be expressed as:
R in the formula
DcBe conductor DC resistance, a is the conductor radius, J
0, J
1For being respectively zeroth order and first-order bessel function, k is a parameter relevant with skin depth
The physical significance of skin depth δ is: current density is reduced to the distance between that and the outside surface of surface current density 1/e (approximately～37%) in the conductor
Wherein ρ is a sample resistivity, and f is a power frequency, and μ is the circumference magnetic permeability of sample.
At this moment, the size of impedance Z is directly proportional with the square root of power frequency f and circumference magnetic permeability μ, so circumference magnetic permeability μ is the main cause that the MI effect produces along with external magnetic field changes.Fig. 3 shows the schematic diagram of amorphous wire magneto-impedance effect.
As seen, the diameter of amorphous wire can influence its skin depth under the high frequency exchange current, and then influences its magneto-impedance effect.And different skin depths, under the effect of extraneous alternating magnetic field, the reactance that can change.Therefore, the amorphous wire of different-diameter size has different resistance and reactance.Along with the increase of power frequency, skin depth δ can reduce.And the circumference magnetic permeability μ of amorphous wire is very big, then can cause reducing of skin depth again.Because the variation of skin depth can cause the impedance of amorphous wire to change thereupon.
Therefore, utilize amorphous wire to make little magnetic and weak magnetic level magnetic field sensor and measure magnetic field, the faint magnetic signal that can realize nanotesla, Pi Te and fly the top grade magnitude is measured.Amorphous wire material produces magneto-impedance effect under incentive condition, show as big variation range, the variation of highly sensitive induced electromotive force on electrical characteristics, and this electromotive force is the reflection of external magnetic field power.
As shown in Figure 5, amorphous wire magneto-impedance sensors of the present utility model mainly is made up of amorphous wire, signal sampling coil, exciting circuit and signals collecting and treatment circuit.
Wherein, amorphous wire, between terminals 3 and terminals 6, because very thin, diameter is micron order, and is little by electric current, length is compared gap and is reached hundred times of gaps in centimetre-sized or millimeter level with its diameter.
Two coils of difference coiling on amorphous wire, wherein the coil between terminals 4 and terminals 5 is as the signal sampling coil, and coil is as reversed trickler between terminals 1 and terminals 2.When the external magnetic field changed, signal sampling is coil-induced to go out the primary voltage signal, and reflection external magnetic field strong and weak and big or small is for measuring the external magnetic field use.Reversed trickler is connected with inductance L 2 and adjustable resistance W1, constitutes negative feedback loop jointly, can reduce the error measured effectively, improves the linearity that the external magnetic field is measured.The coiling reversed trickler is a preferred version on amorphous wire, and amorphous wire magneto-impedance sensors of the present utility model also can not adopt negative feedback loop.
Exciting circuit directly is connected with amorphous wire, preferably, is composed in series by exciting element T1 and resistance R 2.Exciting element T1 can select programmable oscillator on constituting, also can select to provide according to required frequency range any element or the device of pumping signal.The utility model has been selected programmable oscillator herein, shown in programmable oscillator T1 among Fig. 5.Because the structure of exciting circuit unlike the prior art, the selection of excitation signal scope that exciting circuit of the present utility model provided is in prior art the normally used pulse signal, also comprise square-wave signal, sine wave signal and sawtooth signal, even also can comprise the electrical noise signal.According to the difference of practical situations, the frequency of pumping signal can be adjusted or select as required neatly.The type selecting of above-mentioned components and parts and pumping signal thereof has all been passed through the inventor's experimental verification, and is true and effective.
Usually, adopt the driving source of high frequency exchange current as amorphous wire, excitation frequency is high more, and magneto-impedance effect is just strong more.In addition, the amorphous wire magneto-impedance effect incentive condition that produces of relying also has the characteristics of " along excitation ", i.e. " rising edge excitation " or " negative edge excitation "." rising edge " or " negative edge " of excitation signal waveforms are precipitous more, and the magneto-impedance effect of amorphous wire is just strong more.Therefore, owing to influence, in the prior art, adopt pulse signal mostly as pumping signal along drive characteristic and custom use pulse signal.
For square-wave signal and sawtooth signal, part the most precipitous in its signal waveform is generally at nanosecond order.Like this, even in (generally about 1kHZ or more than) under the lower excitation frequency, the magneto-impedance effect of amorphous wire still shows very strongly.And for sinusoidal wave, the variation of its signal waveform is releived relatively, and the effect of " rising edge " or " negative edge " is not obvious relatively.In this case, have only excitation frequency when sine wave signal about 100kHZ or when above, the most precipitous part in the microsecond magnitude, also can encourage amorphous wire to produce comparatively strong magneto-impedance effect greatly effectively in its signal waveform.That is to say, with current signal such as square-wave signal, the sawtooth signal of the certain frequency of continuous alternation, sine wave signal can be as the pumping signal of amorphous wire magneto-impedance effect.Perhaps, with the high frequency triangle wave signal of continuous alternation, or even electrical noise also can be used as the pumping signal of amorphous wire magneto-impedance effect.Further, adopt the current signal of a certain size direct current signal stack alternation still can access similar effect.Especially, use sine wave signal can overcome the at present existing magneto-impedance sensors of utilizing amorphous wire magnetoimpedance technology use the pulse signal excitation and cause circuit is impacted the shortcoming big, that noise is big etc.Owing to widened the range of choice of excitation signal waveforms, therefore amorphous wire magneto-impedance sensors of the present utility model can be selected different pumping signals according to different application scenarios.Fig. 4 shows the output voltage of amorphous wire magneto-impedance sensors of the present utility model under different excitation signal and the relation of measuring magnetic field, wherein, U represents output voltage, H represents external magnetic field, the pumping signal of Fig. 4 (a) is a pulse signal, the pumping signal of Fig. 4 (b) is a square-wave signal, and the pumping signal of Fig. 4 (c) is a sawtooth signal, and the pumping signal of Fig. 4 (d) is a sine wave signal.As can be seen from Figure 4, according to output voltage under the different excitation signal and the relation of measuring magnetic field, different pumping signals can be applied to different occasions.
Directly the mode that is connected with amorphous wire with programmable oscillator encourages amorphous wire, except can playing the effect the same with the crystal oscillator excitation, has more widened amorphous wire to the selection of excitation signal scope.Simultaneously, also strengthen the ease for use of amorphous wire magneto-impedance effect, expanded the application of amorphous wire magneto-impedance effect.
Do not having under the situation of external magnetic field, the electron spin magnetic moment in the amorphous wire can be among a small circle " spontaneously " line up, form one by one little " spontaneous magnetization district ".This spontaneous magnetization district is known as magnetic domain.Usually in unmagnetized amorphous wire, each magnetic domain spontaneous magnetization direction difference does not demonstrate the magnetic on the macroscopic view.When external magnetic field continued to increase, magnetic domain generation domain wall moved with magnetic domain and rotates, and to tend to the direction in magnetic field in various degree, medium just demonstrates the magnetic of macroscopic view to direction of magnetization gradually.
Under suitable component, amorphous wire has good soft magnetic characteristic and special domain structure, and magnetostriction coefficient levels off to zero (～-10
-7).Because negative magnetostriction causes the circumference anisotropy, thereby domain structure is arranged on the farmland ringwise along silk.When in the amorphous wire when the axial exchange current, will produce an alternating magnetic field at circumferencial direction, this direction is just identical with the magnetic domain orientation, is equivalent to produce an easily axle, so magnetic domain is in this side up generation circuital magnetization.And the axial magnetic field that adds is vertical with the magnetic domain orientation, is a hard axis field with respect to circuital magnetization, will stop magnetic domain to be magnetized at circumferencial direction.The result is when Hex=0, and the circumference magnetic permeability is bigger; When the Hex increase, the circumference magnetic permeability sharply reduces with the increase of external magnetic field.The circumference magnetic permeability changes and changes delicately with external magnetic field is the main cause that magneto-impedance effect produces.
Usually add bias magnetic field in the prior art, generally put on the axial of amorphous wire owing to add bias magnetic field, be to put on the axial magnetic field of amorphous wire, with respect to circuital magnetization is a hard axis field, can stop the circumferencial direction magnetization of annular magnetic domain, also promptly weaken the circumference magnetic permeability of amorphous wire.Because it is the principal element that influences magnetic-field measurement sensitivity that circumference magnetic permeability and magnetic domains point reach unanimity, though add bias magnetic field the magnetic domains point of amorphous wire inside is reached unanimity, can improve the sensitivity of magnetic-field measurement to a certain extent, but, because add the circumference magnetic permeability that bias magnetic field has weakened amorphous wire, hinder the raising of magnetic-field measurement sensitivity again to a certain extent, weakened the magneto-impedance effect of amorphous wire.
The external dc bias voltage circuit of inventor's invention can apply amorphous wire and be surrounded on its axial circumference magnetic field, strengthened the circumferencial direction magnetization of annular magnetic domain, make the circumference magnetic permeability increase, and make the sensing of amorphous wire annular magnetic domain reach unanimity.When the Hex increase, the circumference magnetic permeability sharply reduces with the variation of externally-applied magnetic field, thereby has increased the magneto-impedance effect of amorphous wire.Because it is the main cause that magneto-impedance effect produces that the circumference magnetic permeability changes with external magnetic field, therefore, can significantly strengthen the magneto-impedance effect of amorphous wire by the method for taking the applying bias voltage circuit, improve the sensitivity of magnetic-field measurement greatly.On effect, the applying bias voltage circuit is more effective more than adding bias magnetic field.
Referring to Fig. 6, amorphous wire magneto-impedance sensors of the present utility model also comprises the dc offset voltage circuit, preferably is composed in series by inductance L 1 and resistance R 1.The dc offset voltage circuit directly and amorphous wire link, be used for directly providing dc offset voltage, thereby make in amorphous wire, have DC current to pass through to amorphous wire.Choose when suitable when the size of DC current, not only make the circumference magnetic permeability increase, and make the sensing of amorphous wire annular magnetic domain reach unanimity, thereby make that the magneto-impedance effect of amorphous wire is greatly strengthened.Like this, the amorphous wire magneto-impedance sensors has just obtained higher sensitivity, thereby can sense fainter changes of magnetic field.
Therefore, dc offset voltage has significant role to the internal microstructure of conditioning and adjustment amorphous wire, and the sensing of each microcosmic magnetic domain of amorphous wire inside is reached unanimity.When the external magnetic field changed, each microcosmic magnetic domain of amorphous wire inside is upset variation thereupon more flexibly and as one man just.Like this, the amorphous wire magneto-impedance sensors has just had high sensitivity and response speed.
Parallel resonance is applied to frequency-selecting usually, and promptly to the signal of characteristic frequency, circuit shows as pure resistive, and the consumption of reactive power is zero.Shunt capacitance C1 on the signal sampling coil in the utility model amorphous wire magneto-impedance sensors constitutes antiresonant circuit by capacitor C 1 and signal sampling coil, referring to Fig. 7.Because amorphous wire is a kind of soft magnetic material, the signal sampling coil twines and is equivalent to an inductance thereon, so this antiresonant circuit can realize known frequency-selecting effect, promptly selects useful signal.Simultaneously, when the resonance current that puts on exciting current on the amorphous wire and antiresonant circuit with same phase time frequently, " resonance effect " taken place in exciting circuit and antiresonant circuit, and exactly, antiresonant circuit and exciting circuit have constituted " resonance " circuit again jointly.In this case, the amplitude that characterizes the voltage signal of external magnetic field power can be exaggerated several times, even can be amplified to the degree that can directly measure, so just can save the amplification circuits in signals collecting and the treatment circuit.Therefore, antiresonant circuit is set in amorphous wire magneto-impedance sensors of the present utility model not only can realizes known frequency-selecting effect, but also can realize effect that selected effective voltage signal is amplified.The size of the inductance value of signal sampling coil is not only relevant with length, the number of turn, the interior external diameter of signal sampling coil, and is also relevant with the composition and the domain structure of amorphous wire.Parameters such as the interior external diameter of the size of capacitor C 1, the material of amorphous wire and diameter, signal sampling coil and winding turns have determined the resonance frequency of this resonant circuit jointly.By regulating the size of resonance frequency, just can selectively amplify useful signal, thereby greatly improve precision and the accuracy measured.
Fig. 8 shows a preferred embodiment of amorphous wire magneto-impedance sensors of the present utility model, in this embodiment, has adopted the exciting circuit, dc offset voltage circuit and the antiresonant circuit that comprise programmable oscillator simultaneously.But the utility model is not limited thereto, and amorphous wire magneto-impedance sensors of the present utility model also comprises the technical scheme that among the exciting circuit that comprises programmable oscillator, dc offset voltage circuit and the antiresonant circuit three optional one or its two formed together with main configuration.
Signals collecting of the present utility model shown in Fig. 5-8 and treatment circuit T3 can be made up of low-pass filtering or passband filtering circuit, ac amplifier circuit, current rectifying and wave filtering circuit and dc amplification circuit etc.Because signals collecting of the present utility model can adopt the circuit the same with treatment circuit with the signals collecting of amorphous wire magneto-impedance sensors of the prior art with treatment circuit T3, therefore be not repeated here.
The above only is a better embodiment of the present utility model, should not be regarded as the restriction to the utility model scope.All personages who is familiar with this art, technological thought, technical method and the technology contents that discloses according to the utility model think and equivalence variation or content such as simplification, all should fall in the protection domain of the present utility model.
Claims (9)
1. amorphous wire magneto-impedance sensors comprises:
Amorphous wire;
The signal sampling coil is wrapped on the amorphous wire, is used to detect external magnetic field information;
Exciting circuit is used for directly providing pumping signal to amorphous wire; With
Signals collecting and treatment circuit, the voltage signal of acquired signal sampling coil output is also handled it, thus the output dc voltage signal,
It is characterized in that pumping signal comprises square-wave signal, sine wave signal, sawtooth signal or electrical noise signal.
2. amorphous wire magneto-impedance sensors according to claim 1 is characterized in that exciting circuit comprises programmable oscillator, links by second resistance (R2) between programmable oscillator and the amorphous wire.
3. amorphous wire magneto-impedance sensors according to claim 1 and 2, the coil that it is characterized in that being wound on the amorphous wire also comprises reversed trickler, one end ground connection of reversed trickler, the other end connect second inductance (L2) and adjustable resistance (W1), connect with the output terminal of treatment circuit with signals collecting, thereby constitute negative feedback loop jointly.
4. amorphous wire magneto-impedance sensors according to claim 1, it is characterized in that also comprising the dc offset voltage circuit, directly be connected with amorphous wire, be used for providing dc offset voltage to amorphous wire, thereby strengthen the magnetization in a circumferential direction of annular magnetic domain, make the circumference magnetic permeability increase, and make the sensing of amorphous wire annular magnetic domain reach unanimity.
5. amorphous wire magneto-impedance sensors according to claim 2, it is characterized in that also comprising the dc offset voltage circuit, directly be connected with amorphous wire, be used for providing dc offset voltage to amorphous wire, thereby strengthen the magnetization in a circumferential direction of annular magnetic domain, make the circumference magnetic permeability increase, and make the sensing of amorphous wire annular magnetic domain reach unanimity.
6. amorphous wire magneto-impedance sensors according to claim 3, it is characterized in that also comprising the dc offset voltage circuit, directly be connected with amorphous wire, be used for providing dc offset voltage to amorphous wire, thereby strengthen the magnetization in a circumferential direction of annular magnetic domain, make the circumference magnetic permeability increase, and make the sensing of amorphous wire annular magnetic domain reach unanimity.
7. according to the amorphous wire magneto-impedance sensors of claim 4, it is characterized in that the dc offset voltage circuit is composed in series by first inductance (L1) and first resistance (R1).
8. amorphous wire magneto-impedance sensors according to claim 1, it is characterized in that also comprising that antiresonant circuit is made up of electric capacity (C1) and signal sampling coils from parallel connection of coils, not only can select the effective voltage signal, can also amplify selected effective voltage signal.
9. amorphous wire magneto-impedance sensors according to claim 7, it is characterized in that also comprising that antiresonant circuit is made up of electric capacity (C1) and signal sampling coils from parallel connection of coils, not only can select the effective voltage signal, can also amplify selected effective voltage signal.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104345349A (en) * | 2014-10-29 | 2015-02-11 | 上海电机学院 | Fuse detector and detection method thereof |
| CN108037472A (en) * | 2017-11-20 | 2018-05-15 | 华中科技大学 | A kind of new isotropic magnetoelectric transducer |
| CN111308401A (en) * | 2020-04-09 | 2020-06-19 | 西安交通大学 | Detection circuit based on impedance sensitive type magnetic sensor and magnetic sensor |
-
2010
- 2010-07-30 CN CN2010202761748U patent/CN201876534U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104345349A (en) * | 2014-10-29 | 2015-02-11 | 上海电机学院 | Fuse detector and detection method thereof |
| CN108037472A (en) * | 2017-11-20 | 2018-05-15 | 华中科技大学 | A kind of new isotropic magnetoelectric transducer |
| CN111308401A (en) * | 2020-04-09 | 2020-06-19 | 西安交通大学 | Detection circuit based on impedance sensitive type magnetic sensor and magnetic sensor |
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