CN102901859B - Ferrofluid optical current sensor with horizontal bias device and method - Google Patents

Abstract

The invention discloses a ferrofluid optical current sensor with a horizontal bias device. The ferrofluid optical current sensor comprises a monochromatic source, a polarizer, a ferrofluid film, a polarization analyzer and a photoelectric detector; in addition, a horizontal bias magnetic field generator is arranged in the ferrofluid optical current sensor; during use, monochromatic beams become linearly polarized light through the polarizer, the linearly polarized light which is transmitted in the ferrofluid film is rotated at a certain angle through the ferrofluid film under the modulating action of an externally applied longitudinal magnetic field, and the rotation angle is related to the strength of the externally applied longitudinal magnetic field, so the magnitude of the current for generating the externally applied longitudinal magnetic field can be obtained by detecting the rotation angle of the linearly polarized light, the magnetic moment turning speed of magnetic particles can be improved through a magnetic field generated by the horizontal bias magnetic field generator when the magnetic particles in the ferrofluid are modulated by the externally applied longitudinal magnetic field, the response time is shortened, and the sensitivity and the accuracy of the sensor are improved; and based on the sensor, the invention also discloses a current measuring method.

Description

With ferrofluid optical profile type current sensor device and the method for transverse bias device

Technical field

The present invention relates to a kind of ferrofluid optical profile type current sensor device with transverse bias device, the present invention also utilizes this kind of ferrofluid optical profile type current sensor device simultaneously, achieves a kind of method that can improve ferrofluid optical profile type performance of current sensors, reach current detecting object.

Background technology

The general principle of ferrofluid optical profile type current measuring method is longitudinal magnetic rotation effect of ferrofluid, namely when monochromatic light beam is by the ferrofluid that has longitudinal magnetic field to modulate, polarised light direction of vibration can rotate, and the size of the anglec of rotation is relevant with the power of modulated magnetic field, therefore the size by measuring the polarised light direction of vibration anglec of rotation derives the intensity of modulated magnetic field.And modulated magnetic field is generally produced by a certain electric current to be measured, according to the relation in electric current and magnetic field, the parameter of electric current to be measured can be obtained.

The major defect of existing ferrofluid optical profile type electric current sensing method is that long, the sensitivity of the response time of non-constant current and accuracy are low.Above-mentioned defect is ferrofluid when being magnetized under externally-applied magnetic field effect, and the relaxation time longlyer causes in magnetic-particle magnetic moment and the convergent process of outfield orientation.

Summary of the invention

In view of this, an object of the present invention is to provide a kind of ferrofluid optical profile type current sensor device with transverse bias device; Two of object of the present invention is to provide the ferrofluid optical profile type current sensor device of a kind of utilization with transverse bias device, realizes the method for current detecting.

An object of the present invention is achieved through the following technical solutions:

Ferrofluid optical profile type current sensor device with transverse bias device of the present invention, comprises monochromatic source, the polarizer, ferrofluid film, analyzer, photodetector, pretreatment module, data acquisition unit, data processor, control module, driver module, Switching Power Supply, field power supply, Man Machine Interface, magnetic pole I and magnetic pole II;

The surface of described ferrofluid film keeps vertical with the direction in the magnetic field that electric current to be measured produces or magnetic field to be measured, described monochromatic source is used for sending inspection light beam, this light beam becomes the certain linearly polarized light of direction of vibration after the polarizer, linearly polarized light pass perpendicularly through by the ferrofluid film of magnetic field modulation simultaneously its direction of vibration rotate;

Described analyzer is arranged at the opposite side of ferrofluid film, and coordinate photodetector that postrotational linearly polarized light light intensity magnitude is converted into voltage signal, and export pretreatment module to, after described pretreatment module carries out filtering and amplification process to signal, export data acquisition unit to, analog signal is converted to data signal and sends into data processor by described data acquisition unit;

After described data processing and control module are used for carrying out calculation process to the result recorded, export the relevant information of parameter to be measured to Man Machine Interface, simultaneously, described data processor, according to the type in the result Cutoff current/magnetic field measured and parameter area, sends corresponding adjustment instruction to control module;

Described control module is used for the excitation adjustment instruction sent according to data processor, exports the control signal of field power supply, to regulate the relevant parameter in transverse bias magnetic field;

Described field power supply field power supply 12 is under the regulating action of control signal, for providing exciting current for magnetic pole I 14 and magnetic pole II 15, make magnetic pole produce magnetic field parameter and meet control object, described magnetic pole I and magnetic pole II is arranged at ferrofluid film, the perpendicular transverse magnetic field in a direction and the polarised light direction of propagation is produced, with the Magnetic moment reversal of magnetic-particle in auxiliary ferrofluid under the effect of field power supply.

Further, described device also comprises driver module, the control signal that described control module sends through circuit in driver module amplification, isolate and adjust after, become the control signal that in field power supply, power electronic element can accept;

Further, described device also comprises Switching Power Supply, and the electric energy needed in described monochromatic source, photodetector, pretreatment module, data acquisition unit, data processor, control module and driver module is provided by Switching Power Supply;

Further, described magnetic pole I comprises electromagnet I and coil I, magnetic pole II comprises electromagnet II and coil II, described electromagnet I and electromagnet II is cylinder, described coil I and coil II is enamel-covered wire and is closely respectively around on electromagnet I and electromagnet II, two the end of a thread ends of described coil I are respectively current input terminal mouth P1 and current output terminal mouth P2, two the end of a thread ends of described coil II are respectively current input terminal mouth P3 and current output terminal mouth P4, two electromagnet opposing end surfaces are magnetic boots structure and the axis of two magnetic poles overlaps, at a distance of 1 ~ 6mm;

Further, the diameter of described electromagnet I and electromagnet II is 10 ~ 20mm, and length is 25 ~ 60mm, and material is DT4 pure iron;

Further, described magnetic boots border width is 1.5mm;

Further, the enamel-covered wire that described coil I and coil II is AWG27 by model is formed, each 50 circles.

Two of object of the present invention is achieved through the following technical solutions:

Said method comprising the steps of:

Step one: ferrofluid optical profile type current sensor device is put into magnetic field to be measured, wherein ferrofluid film is the thin slice made with ferrofluid, makes the direction of vibration of polarised light rotate under the effect of modulated magnetic field;

Step 2: both sides magnetic pole I and magnetic pole II being positioned in a symmetrical manner respectively ferrofluid film, in the direction perpendicular with modulated magnetic field, a transverse bias magnetic field is applied to ferrofluid film, improve ferrofluid to the response speed of outside Longitudinal Magnetic-field Has;

Step 3: coordinate photodetector that postrotational linearly polarized light light intensity magnitude is converted into voltage signal by analyzer, and export pretreatment module to, after described pretreatment module carries out filtering and amplification process to signal, export data acquisition unit to, analog signal is converted to data signal and sends into data processor and carries out calculation process by described data acquisition unit, the intensity of modulated magnetic field is derived by the size measuring the polarised light direction of vibration anglec of rotation, and modulated magnetic field is produced by electric current to be measured, according to the relation in electric current and magnetic field, the parameter of electric current to be measured can be obtained.

The invention has the beneficial effects as follows:

1. device of the present invention applies a transverse bias magnetic field by the direction perpendicular at modulated magnetic field, effective raising ferrofluid is to the response speed of outside Longitudinal Magnetic-field Has, thus magnetic-particle response time under outside Longitudinal Magnetic-field Has effect in shortening ferrofluid, strengthen the sensitivity of ferrofluid magneto-optic effect, optimize the dynamic characteristic of sensor;

2. the present invention expands the object type of carrying out current/magnetic field sensing and measurement based on ferrofluid longitudinal flux luminous effect, change can not only be carried out to the parameter of direct current/stationary magnetic field, alternating current/alternating magnetic field to send, but also the parameter of paired pulses electric current/pulsed magnetic field can carry out change and send.

Other advantages of the present invention, target and feature will be set forth to a certain extent in the following description, and to a certain extent, based on will be apparent to those skilled in the art to investigating hereafter, or can be instructed from the practice of the present invention.Target of the present invention and other advantages can be realized by description below and claims and be obtained.

Accompanying drawing explanation

In order to make the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the present invention is described in further detail, wherein:

Fig. 1 is the structured flowchart of the ferrofluid optical profile type current sensor device with transverse bias device;

Fig. 2 is the ferrofluid optical profile type current sensor device schematic diagram with transverse bias device;

Fig. 3 produces transverse bias field pole schematic diagram;

Fig. 4 is a concrete implementing circuit connection diagram of the present invention.

Detailed description of the invention

Hereinafter with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail.Should be appreciated that preferred embodiment only in order to the present invention is described, instead of in order to limit the scope of the invention.

As depicted in figs. 1 and 2, ferrofluid optical profile type current sensor device with transverse bias device of the present invention, comprises monochromatic source 1, the polarizer 2, ferrofluid film 3, analyzer 4, photodetector 5, pretreatment module 6, data acquisition unit 7, data processor 8, control module 9, driver module 10, Switching Power Supply 11, field power supply 12, Man Machine Interface 13, magnetic pole I14 and magnetic pole II15;

The surface of ferrofluid film 3 keeps vertical with the direction in the magnetic field that electric current to be measured produces or magnetic field to be measured, described monochromatic source 1 is for sending inspection light beam, this light beam becomes the certain linearly polarized light of direction of vibration after the polarizer 2, linearly polarized light pass perpendicularly through by the ferrofluid film of magnetic field modulation simultaneously its direction of vibration rotate;

Analyzer 4 is arranged at the opposite side of ferrofluid film 3, and coordinate photodetector 5 that postrotational linearly polarized light light intensity magnitude is converted into voltage signal, and export pretreatment module 6 to, after described pretreatment module 6 pairs of signals carry out filtering and amplification process, export data acquisition unit 7 to, analog signal is converted to data signal and sends into data processor 8 by described data acquisition unit 7;

After data processor 8 carries out calculation process to the result recorded, export the relevant information of parameter to be measured to Man Machine Interface, meanwhile, data processor, according to the type in the result Cutoff current/magnetic field measured and parameter area, sends corresponding adjustment instruction to control module 9;

The excitation adjustment instruction of control module 9 for sending according to data processor, switch element in field power supply is controlled, in the present invention, data processor and control module process the data signal that data acquisition unit exports on the one hand, the design idea of reflection optical profile type current sensor, comprises the value of current/magnetic field, the Changing Pattern etc. of current/magnetic field; Export on the other hand the control signal of field power supply, to regulate the relevant parameter in transverse bias magnetic field, comprise the size in transverse bias magnetic field and Changing Pattern etc.In the present embodiment, the control signal that control module 9 sends through circuit in driver module 10 amplification, isolate and adjust after, become the control signal that in field power supply 12, power electronic element can accept.

Field power supply 12, under the regulating action of control signal, for providing exciting current for magnetic pole I 14 and magnetic pole II 15, making magnetic pole produce magnetic field parameter and meeting control object.Magnetic pole I 14 and magnetic pole II 15 is arranged at ferrofluid film, applies transverse bias magnetic field in various degree on ferrofluid film 3 according to the parameter of exciting current.

In the present invention, can also increase signal transmitting module as required, the control signal for data processing and control module being exported carries out the conversion of the power amplification of signal, electrical isolation and signal form, meets the requirement of field power supply to control signal form.

In the present embodiment, the electric energy needed in described monochromatic source, photodetector, pretreatment module, data acquisition unit, data processor, control module and driver module is provided by Switching Power Supply 11.

As shown in Figure 2, in device of the present invention, the magnetic direction that magnetic pole I and magnetic pole II produces is perpendicular to direction of beam propagation, and ferrofluid film 3 overlaps with the axis of magnetic pole I, magnetic pole II.

As shown in Figure 3, magnetic pole I 14 comprises electromagnet I and coil I, magnetic pole II 15 comprises electromagnet II and coil II, electromagnet I and electromagnet II is M1 and M2 in figure, coil I and coil II is C1 and C2 in figure, electromagnet I and electromagnet II is cylinder, coil I and coil II is enamel-covered wire and is closely respectively around on electromagnet I and electromagnet II, two the end of a thread ends of coil I are respectively current input terminal mouth P1 and current output terminal mouth P2, two the end of a thread ends of described coil II are respectively current input terminal mouth P3 and current output terminal mouth P4, two electromagnet opposing end surfaces are magnetic boots structure and the axis of two magnetic poles overlaps, at a distance of 1 ~ 6cm, can not more than 6mm.In the present embodiment, the diameter of electromagnet I and electromagnet II is 12mm, and length is 40mm, and material is DT4 pure iron.Described magnetic boots border width is 1.5mm.The enamel-covered wire that described coil I and coil II is AWG27 by model is formed, each 50 circles.

Fig. 4 is the specific implementation circuit that the present invention adopts, and wherein, wherein R1-R8 is resistive element, and C1-C18 is capacity cell, and F1 is fuse, and B1 is rectifier bridge, and L1-L6 is inductance element, and D1-D8 is diode, and VT1-VT4 is IGBT.

J1 is single phase poaer supply input plug, comprises three terminals, and wherein the L end representative of plug is connected with the live wire of power supply, and the representative of N end is connected with the zero line of power supply, and the representative of G end is connected with ground wire.J2 is the output distributing box of field power supply, comprises two-way inlet wire and four tunnel outlets, and wherein two input terminals are switched on two outlet terminals respectively, and an input terminal is connected with outlet terminal P1 with P3, and another input terminal is connected with outlet terminal P2 with P4.P1 and P2 receives P1 and the P2 port of magnetic pole 1 shown in Fig. 3 respectively; P3 and P4 receives P3 and the P4 port of magnetic pole 2 shown in Fig. 3 respectively; TA1 is current transformer, the output current of field power supply is fed back to control module, and compares between the set-point of data processor, forms the closed-loop control to field power supply output current.T1 is output transformer, and its function is the effect isolated output voltage and boost.T2 is voltage transformer, the output voltage of field power supply is fed back to control module, and compares between the set-point of data processor, forms the closed-loop control to field power supply output voltage.S1 is power switch, is in normally open, when needs field power supply works, is closed electrical source switch S1 after single phase poaer supply input plug and 220V single phase poaer supply are connected.

A-quadrant in figure is filter circuit, comprise resistance R1, R2, electric capacity C1, C3, C4 ~ C9 and inductance L 1 ~ L3, B region is that IGBT voltage exports on-off circuit, be divided into 4 groups of electronic circuits, each group includes an igbt transistor, the base stage of each igbt transistor is connected to a control output end, road of driver module respectively, the control signal triggering and conducting exported by driver module, by the triggering and conducting of different electronic circuit, load the voltage input side of different voltage signals to output transformer T1, C region in figure is excitation output circuit, J2 is exported to for the voltage after being boosted by output transformer T1.

In actual applications, the function in each region of foregoing circuit adopts as the concrete soft copy in figure realizes incessantly, as long as can realize corresponding function, different soft copies also can be adopted to carry out assembling and realize.

measuring principle of the present invention is as follows:

The core component of sensing device is the Sandwich film that ferrofluid is made, and this film is based on the magnetic rotation effect of ferrofluid under outside Longitudinal Magnetic-field Has effect.Fixing functional relation is had between the angle that after printing opacity ferrofluid film, polarised light plane of polarization rotates and outside Longitudinal Magnetic-field Has intensity.

The light beam that monochromatic source sends becomes linearly polarized light after the polarizer, and after the ferrofluid film of externally-applied magnetic field modulation, the angle of polarization there occurs rotation to a certain fixed-direction, then arrives photodetector through analyzer analyzing.The distance L that magnetic rotation angle θ and the light in light vibration face pass through in media as well and applied field strengths H is directly proportional at the component of optical propagation direction.The size of the anglec of rotation is:

θ=μ ₀VHL （1）

Wherein θ is magnetic rotation angle, and V is the Verdet constant of magnet-optical medium, and H is the size of the magnetic field intensity along optical path direction, and L is light path or the magnet-optical medium thickness along optical path direction.

From the angle analysis of electromagnetic theory, incident polarized lightwave is as a kind of electromagnetic wave, and when it is from the ferrofluid with magnetic moment after transmission, polarisation of light state changes.This is material and the interactional result of electromagnetic Electric and magnetic fields with magnetic moment.The magnetization of ferrofluid under additional modulated magnetic field effect is a relaxation process, and therefore its magnetic rotation effect also exists the relaxation time.In other words, the relaxation process of ferrofluid magnetic rotation effect is determined by the magnetization relaxation of its internal magnetization particle under additional magnetic fields.There is substantial connection with between particle size in the magnetization relaxation characteristic of magnetic-particle: the larger particle corresponding longer relaxation time, and its relaxation time of less particle is also relatively short.

In ferrofluid, the magnetic history of magnetic nanoparticle not only depends on the character of ferrofluid itself, but also relevant with the character of the physicochemical properties of magnetic nanoparticle in ferrofluid, microstructure and externally-applied magnetic field.

The polarised light of monochromatic laser beam after the polarizer is regarded as input signal, the polarized light intensity that photodetector measurement is obtained is output signal, then the ferrofluid film under outside Longitudinal Magnetic-field Has effect and analyzer can be regarded as a time-independent stational system of transmission characteristic.According to the convolution theorem in network analysis, the ideal unitary square-wave pulse receptance function after known normalization and the convolution of input signal are the response of this system at this input signal.The transmission characteristic of ferrofluid under longitudinal modulation magnetic fields can be expressed as:

$I\left(t\right)=\mathrm{\ψ}\left(t\right)*H\left(t\right)={\∫}_{-\∞}^t\mathrm{\ψ}(t-u)\·H\left(u\right)\mathrm{du}---\left(1\right)$

Wherein ψ (t) is the ideal unitary square-wave pulse receptance function after normalization, the time-domain function that H (t) is modulated magnetic field.As a polydisperse system, the diameter D of magnetic-particle in ferrofluid _iobeys logarithm normal distribution, meets:

$p\left(D\right)=\frac{1}{{\mathrm{D\σ}}_D\sqrt{2\mathrm{\π}}}\exp (-\frac{1}{2{\mathrm{\σ}}_D^2}{\left(\ln \frac{D}{D_0}\right)}^2)---\left(2\right)$

Wherein σ _dthe standard deviation of particle diameter, D ₀it is the average diameter of particle.

Under additional magnetic fields, effective relaxation time of ferrofluid is relevant with the particle size of magnetic-particle, and meets:

${\mathrm{\τ}}_{\mathrm{eff}}=\frac{{\mathrm{\τ}}_N{\mathrm{\τ}}_B}{{\mathrm{\τ}}_N+{\mathrm{\τ}}_B}---\left(3\right)$

Wherein τ _nfor the Neil relaxation time (N é el Relaxation Time) and τ _n=1/f ₀exp (KV/kT), f here ₀≈ 10 ⁹hz, K are the anisotropy constants of material, anisotropy constant K=2.0 × 10 of magnetic nanoparticle in ferrofluid ⁴j/m ³, τ _bfor Blang's relaxation time (Brownian Relaxation Time) and τ _b=3V η ₀/ kT, here V is the volume of particle, η ₀the viscosity of base fluid.For water-based ferrofluid, its viscosity is η ₀=0.001kgm ^-1s ^-1.

In ferrofluid, the magnetic history of magnetic nanoparticle not only depends on the character of ferrofluid itself, but also relevant with the character of the physicochemical properties of magnetic nanoparticle in ferrofluid, microstructure and externally-applied magnetic field.Formation and the switching process of magnetic domain is observed with means such as Lorentz electron microscope or magnetic force microscopys; The dynamic switching process of magnetic moment is described by numerical solution Landau-Lifshitz-Gilbert (LLG) equation.LLG equation contains the attenuation term around the Lamor precession item of Equivalent Magnetic Field and phenomenological ground description system energy dissipation.Which overcome the shortcoming in the precession equation of Landau and Lifshitz proposition, can be used for describing comparatively high attenuation damped coefficient system.Because LLG equation is nonlinear differential equation, it only has just has analytic solutions in some special cases.R.Kikuchi have studied the minimum flip-flop transition under the demagnetizing field effect that single domain particle has at additional static magnetic field and particle itself, and find when attenuation coefficient α=1, the flip-flop transition of magnetic moment is the shortest.R.L.Stamps and B.Hillebrands proposes the bias voltage magnetic field applying direct current significantly can improve the switching field that the required applying of upset occurs magnetic moment.In addition, on stationary magnetic field, superimposed RF magnetic field and pulsed magnetic field all can cause switching field intensity or duration to be reduced.

Under additional magnetic fields, the magnetic moment of single domain particle can be studied by Landau-Lifshitz-Gilbert (LLG) equation in outfield and the magnetization reversal dynamics under having damping situation

$\frac{\mathrm{dM}}{\mathrm{dt}}=-\mathrm{\γ}{M\×H}_{\mathrm{eff}}+\frac{\mathrm{\α}}{M}M\×\frac{\mathrm{dM}}{\mathrm{dt}}---\left(4\right)$

Wherein γ is gyromagnetic ratio; α is dissipation factor; M is the intensity of magnetization of single-domain particle; Heff is total effective field that magnetic-particle is subject to.Due to the existence dissipated, magnetization intensity vector also finally turn to the direction consistent with anti-field by along effective field Heff precession.

The orientation M of magnetization intensity vector represents with two angle θ and φ.Uniaxial anisotropy is established easily to change axle in z-axis direction at this.Effective field Heff comprises the upset field making magnetization reversal in the bias voltage field in x-direction and effective anisotropy field km _z=(2K/M) m _z, K is anisotropy energy constant and m here _z=M _z/ | M|=M _z/ M.So effective field can be write as

$H_{\mathrm{eff}}=({\mathrm{km}}_z-h)\hat{z}+h^{\′}\left(t\right)\hat{x}---\left(5\right)$

An amplitude is h ₀', angular frequency is that the oscillating bias voltage field of ω can be write as

h′(t)=h ₀′cosωt (6)

For simplicity, about can be changed into t '=tM γ (1+ α the time ²) ^-1, therefore equation (4) and (5) can be write as

$M^2\frac{\mathrm{dM}}{d{t}^{\′}}=-\mathrm{MM}\×H_{\mathrm{eff}}-\mathrm{\αM}\×\left({M\×H}_{\mathrm{eff}}\right)---\left(7\right)$

$H_{\mathrm{eff}}=({\mathrm{km}}_z-h)\hat{z}+h^{\′}\left(t^{\′}\right)\hat{x}---\left(8\right)$

According to equation (5), (6) and (7), magnetization vector obtains by solving the equation group of following two associations over time:

Wherein H _{eff, i}(i=x, y, z) is H _effat x, y, the component of z-axis.

Owing to having uniaxial anisotropy, the final orientation of magnetic moment will be tending towards+z or-z direction.Without under externally-applied magnetic field situation, system has two energy-minimums of equal value, and two lowest energy states are separated by an energy barrier.At Stoner-Wahlfarth(SW) in model, if reduce the energy barrier between two potential wells without outfield, when zero temperature, certain state that magnetization vector will be stable in two lowest energy states.If initial magnetization vector is in+z direction, only have when upset field h>k just can make Magnetic moment reversal; If h<k, to all angle φ, energy barrier prevents magnetic moment from initial state (mz ≈+1, θ ≈ 0) to the upset of final state (mz ≈-1, θ ≈ π).But for a certain fixed angle φ, although there is energy barrier to exist, utilize the transverse bias field that little, magnetization reversal has become easily.

Based on above measuring principle, measuring method of the present invention comprises the following steps:

Step one: ferrofluid optical profile type current sensor device is put into magnetic field to be measured, wherein ferrofluid film is the thin slice made with ferrofluid, makes the direction of vibration of polarised light rotate under the effect of modulated magnetic field;

Step 2: both sides magnetic pole I and magnetic pole II being positioned in a symmetrical manner respectively ferrofluid film, in the direction perpendicular with modulated magnetic field, a transverse bias magnetic field is applied to ferrofluid film, improve ferrofluid to the response speed of outside Longitudinal Magnetic-field Has;

Step 3: coordinate photodetector that postrotational linearly polarized light light intensity magnitude is converted into voltage signal by analyzer, and export pretreatment module to, after described pretreatment module carries out filtering and amplification process to signal, export data acquisition unit to, analog signal is converted to data signal and sends into data processor and carries out calculation process by described data acquisition unit, based on Malus' law, by measuring the size of the polarised light direction of vibration anglec of rotation, thus derive the intensity of modulated magnetic field, and modulated magnetic field is produced by electric current to be measured, according to the relation in electric current and magnetic field, the parameter of electric current to be measured can be obtained.

What finally illustrate is, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although with reference to preferred embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that, can modify to technical scheme of the present invention or equivalent replacement, and not departing from aim and the scope of the technical program, it all should be encompassed in the middle of right of the present invention.

Claims (7)

1. with the ferrofluid optical profile type current sensor device of transverse bias device, it is characterized in that: described device comprises monochromatic source, the polarizer, ferrofluid film, analyzer, photodetector, pretreatment module, data acquisition unit, data processor, control module, driver module, Switching Power Supply, field power supply, Man Machine Interface, magnetic pole I and magnetic pole II;

The surface of described ferrofluid film keeps vertical with the direction in the magnetic field that electric current to be measured produces or magnetic field to be measured, described monochromatic source is used for sending inspection light beam, this light beam becomes the certain linearly polarized light of direction of vibration after the polarizer, linearly polarized light pass perpendicularly through by the ferrofluid film of magnetic field modulation simultaneously its direction of vibration rotate;

Described analyzer is arranged at the opposite side of ferrofluid film, and coordinate photodetector that postrotational linearly polarized light light intensity magnitude is converted into voltage signal, and export pretreatment module to, after described pretreatment module carries out filtering and amplification process to signal, export data acquisition unit to, analog signal is converted to data signal and sends into data processor by described data acquisition unit;

After described data processing and control module are used for carrying out calculation process to the result recorded, export the relevant information of parameter to be measured to Man Machine Interface, simultaneously, described data processor, according to the type in the result Cutoff current/magnetic field measured and parameter area, sends corresponding adjustment instruction to control module;

Described control module is used for the excitation adjustment instruction sent according to data processor, exports the control signal of field power supply, to regulate the relevant parameter in transverse bias magnetic field;

Described field power supply field power supply 12 is under the regulating action of control signal, for providing exciting current for magnetic pole I14 and magnetic pole II15, make magnetic pole produce magnetic field parameter and meet control object, described magnetic pole I and magnetic pole II is arranged at ferrofluid film, the perpendicular transverse magnetic field in a direction and the polarised light direction of propagation is produced, with the Magnetic moment reversal of magnetic-particle in auxiliary ferrofluid under the effect of field power supply;

Described magnetic pole I comprises electromagnet I and coil I, magnetic pole II comprises electromagnet II and coil II, described electromagnet I and electromagnet II is cylinder, described coil I and coil II is enamel-covered wire and is closely respectively around on electromagnet I and electromagnet II, two the end of a thread ends of described coil I are respectively current input terminal mouth P1 and current output terminal mouth P2, two the end of a thread ends of described coil II are respectively current input terminal mouth P3 and current output terminal mouth P4, two electromagnet opposing end surfaces are magnetic boots structure and the axis of two magnetic poles overlaps, and are apart 1 ~ 6mm.

2. the ferrofluid optical profile type current sensor device with transverse bias device according to claim 1, it is characterized in that: described device also comprises driver module, the control signal that described control module sends through circuit in driver module amplification, isolate and adjust after, become the control signal that in field power supply, power electronic element can accept.

3. the ferrofluid optical profile type current sensor device with transverse bias device according to claim 1 and 2, it is characterized in that: described device also comprises Switching Power Supply, the electric energy needed in described monochromatic source, photodetector, pretreatment module, data acquisition unit, data processor, control module and driver module is provided by Switching Power Supply.

4. the ferrofluid optical profile type current sensor device with transverse bias device according to claim 1 or 2 or 3, is characterized in that: the diameter of described electromagnet I and electromagnet II is 10 ~ 20mm, and length is 25 ~ 60mm, and material is DT4 pure iron.

5. the ferrofluid optical profile type current sensor device with transverse bias device according to claim 1 or 2 or 3, is characterized in that: described magnetic boots border width is 1.5mm.

6. the ferrofluid optical profile type current sensor device with transverse bias device according to claim 1 or 2 or 3, is characterized in that: the enamel-covered wire that described coil I and coil II is AWG27 by model is formed, each 50 circles.

7. adopt as arbitrary in claim 1 to 6 as described in ferrofluid optical profile type current sensor device carry out the method for current detecting, it is characterized in that: said method comprising the steps of:

Step one: ferrofluid optical profile type current sensor device is put into magnetic field to be measured, wherein ferrofluid film is the thin slice made with ferrofluid, makes the direction of vibration of polarised light rotate under the effect of modulated magnetic field;

Step 2: both sides magnetic pole I and magnetic pole II being positioned in a symmetrical manner respectively ferrofluid film, in the direction perpendicular with modulated magnetic field, a transverse bias magnetic field is applied to ferrofluid film, improve ferrofluid to the response speed of outside Longitudinal Magnetic-field Has;

Step 3: coordinate photodetector that postrotational linearly polarized light light intensity magnitude is converted into voltage signal by analyzer, and export pretreatment module to, after described pretreatment module carries out filtering and amplification process to signal, export data acquisition unit to, analog signal is converted to data signal and sends into data processor and carries out calculation process by described data acquisition unit, the intensity of modulated magnetic field is derived by the size measuring the polarised light direction of vibration anglec of rotation, and modulated magnetic field is produced by electric current to be measured, according to the relation in electric current and magnetic field, the parameter of electric current to be measured can be obtained.