CN201007728Y - Array type giant magneto-impedance effect current sensor - Google Patents

Abstract

The utility model belongs to the technical field of current measuring devices, in particular to a non-contact sensor for measuring current by generating a magnetic field change based on a giant magneto-impedance (GMI) effect. It consists of array type GMI amorphous current sensor probes (1), (2), oscillation and rectification circuits (3), (4), subsequent zeroing amplifiers (5) and digital displays (6); array type current sensor probes (1 ), (2) are welded in series by a plurality of rectangular amorphous strip units (8) with good soft magnetic properties by copper wires (9), and the requirements of the two array probes (1) and (2) are the same, It is placed on both sides of the current-carrying wire (10) in parallel and symmetrically. The design adopts a dual-probe differential structure, which can amplify the signal, improve the signal-to-noise ratio, and improve the linearity of the output curve; the utility model has a small structure, high sensitivity, economical and practical, and can be widely used in the measurement of current in various fields of production and scientific research.

Description

Array type giant magneto-impedance effect current sensor

technical field

The utility model belongs to the technical field of current measuring devices, in particular to an array type giant magneto-impedance (GMI) effect current sensor.

Background technique

Current measurement is an important issue in various fields of production and scientific research. Now many new technologies and materials are applied to current measurement devices. The most commonly used current sensors are transformer-type current sensors, Rogowski coils, shunt resistors, and Hall (Hell) element current sensors, etc., but these sensors have certain defects. The transformer-type current sensor and the Rogowski coil measure the current, requiring particularly precise coil winding, high signal processing requirements, and can only be used for the measurement of AC current; the shunt resistance can measure AC and DC current, but it is only a The resistance consumes a lot of power; the output signal of the Hall device changes little, and there is a certain anisotropy of the magnetic field direction when measuring the current, and the circuit of the above sensor is too complicated and the cost is high.

It was not until 1992 that K. Mohri and others from Nagoya University in Japan discovered the giant magneto-impedance (GMI) effect in CoFeSiB soft magnetic amorphous wire, and now the maturity of the amorphous material manufacturing process has stabilized the performance. , high sensitivity, fast response, non-contact, low-cost magnetic sensor design possible.

Utility model content

The purpose of this utility model is to provide an array type GMI effect current sensor based on the giant magneto-impedance (GMI) effect design of the amorphous soft magnetic strip, which can well solve the problem of making the giant magneto-impedance change rate One-to-one correspondence with the magnetic field generated by the detected current, low noise, and enlarged measurement range; and the utility model is simple in structure, economical and practical.

The principle of the giant magneto-impedance current sensor is that a high-frequency AC signal is applied to the amorphous soft magnetic strip in the circuit, and there will be a corresponding high-frequency AC voltage signal at both ends of the amorphous strip; when the external current to be measured generates a magnetic field that acts on the non-crystalline soft magnetic strip When the crystal strip is on, the AC impedance of the amorphous strip will change, and the high-frequency voltage signal at both ends will also change. The change of this high-frequency voltage signal can be used to reflect the change of the external current to be measured.

The array type giant magneto-impedance effect current sensor described in the utility model is made up of array type GMI amorphous current sensor probe 1,2, oscillation and rectification circuit 3,4 and follow-up zeroing amplifier 5, digital display 6; It is characterized in that :

(1) Array type current sensor probes 1 and 2 are welded in series by a plurality of rectangular amorphous strip units 8 with good soft magnetic properties and copper wires 9, and the requirements of the two array type probes 1 and 2 are the same,

It is placed parallel and symmetrically on both sides of the current-carrying wire 10;

(2) A permanent magnet 7 is arranged below the energized wire 10, through which a bias magnetic field is provided to fix the working points of the array probes 1 and 2 on the curve of the GMI rate of the amorphous strip material with the magnetic field, so as to adopt a differential structure , the size of the bias magnetic field is determined by the magnetic field strength of the permanent magnet 7 and the distance from the permanent magnet 7 to the probes 1 and 2;

(3) Oscillating and rectifying circuits 3 and 4 are all made up of Corbitz oscillating circuit 11, preamplifier circuit 12 and rectifying circuit 13. Corbitz oscillating circuit 11 provides high-frequency AC signals for the probe, and the input terminal of preamplifying circuit 12 The two ends of the amorphous strip unit 8 are connected, and the amplified signals at both ends of the amorphous strip unit 8 are connected to the rectification circuit 13 at the output terminal, and the rectification circuit 13 converts the high-frequency AC signal generated by the amorphous strip into twice the peak value of the AC signal DC signal U ₁ , U ₂ ,

(4) The above-mentioned DC signals U ₁ and _U2 are connected to the zero-adjustment output amplifier 5, and then sent to the digital display 6 after calculation and zero-adjustment to obtain the current I to be measured.

The Corbitz oscillating circuit 11 mentioned in the utility model is composed of transistors with a cut-off frequency of 3-60 MHz, and the resistance values of the two voltage-dividing resistors 16 and 17 between the base and the DC power supply V _cc and between the base and the ground are equal A crystal oscillator (crystal oscillator) 15 with a frequency of 1-20 MHz and an oscillation capacitor 14 are connected in series between the base and the ground; one end of the probe 1 is grounded, and the other end is connected in series with the load resistor 21 to the emitter of the transistor, and the probe 1 It exists as part of the emitter load, and the oscillation frequency value of the Corbitz oscillation circuit 11 depends on the frequency of the crystal oscillator 15, that is, the operating frequency of the probe 1 amorphous band; the frequency range of the crystal oscillator 15 is preferably 1-12MHz, and the optimum frequency The range is 2 ~ 5MHz, you can use a quartz crystal oscillator.

The arrayed current sensor probes 1 and 2 are welded in series by 4 to 30 rectangular amorphous strip units 8 with good soft magnetic properties and copper wires 9. The length of the amorphous strip units is 5 to 25mm and the width is 0.5 ~ 10mm, thickness 10um ~ 40um, the distance between two amorphous strip units is 0.5 ~ 10mm; and the requirements of the two array probes 1 and 2 are the same; the sensor adopts a differential structure, and the two array probes 1 and 2 They are symmetrically placed on both sides of the conducting wire 10, and the distance from the wire to the array sensor probe is 1-20 mm.

The amorphous strip unit 8 does not need annealing treatment, and the Co amorphous strip or the thin strip of Fe-based nanocrystalline material with a maximum giant magneto-impedance change rate (GMI rate) of more than 50% is suitable for this patent. A permanent magnet 7 is used to provide a bias magnetic field, and the range of the bias magnetic field is 10-30Oe;

As a further preferred mode of this patent, the frequency of the best crystal oscillator 15 is 3.5795MHz; the amorphous strip unit 8 is a CoFeSiB amorphous strip with a larger giant magneto-impedance rate of change (GMI rate), The length of the amorphous strip unit is 10mm, the width is 2.5mm, and the thickness is 30um. The distance between two amorphous strip units is 1mm, and the distance between the wire and the array sensor probe is 5mm. The bias magnetic field is provided by ferrite or NdFeB permanent magnet 7, and the bias field range is 10-20Oe.

The used amorphous belt unit 8 of this patent is a CoFeSiB amorphous belt, which is prepared by a single-roller quick quenching method. First, Co, Fe, Si, B with a purity of more than 99.9% are used in a certain ratio (substance amount Co The specific gravity is more than 60%, the proportion of B is 8% to 20%, and the rest are Si and Fe), which are melted into alloy blocks in a vacuum electric arc furnace; after breaking the alloy blocks, put the fragments in the quartz tube; In the belt throwing machine (WK MS-I), the distance between the quartz tube mouth and the copper roller is about 2mm, and the copper roller rotates at a speed of 25m/s; argon gas is added to the quartz tube, and the molten alloy is sprayed onto the copper roller to form thin strips.

In the above technical solution, when the current passes through the wire 10, an annular magnetic field H _i is generated;

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="I"\; filenames="Y20072009335700111.png,Y20072009335700121.png"\; state="\{\{state\}\}">I</figure-callout></span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;d</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, I is the current to be measured in the wire. Because the annular magnetic field H _i generated by the current acts differently in the radial direction of each amorphous strip unit 8 of the probe, but the output voltage signal of the probe can reflect the average GMI effect of the amorphous strip unit 8 .

The permanent magnet 7 is used to provide the bias magnetic field H _b to fix the working points of the array probes 1 and 2 on the GMI rate versus magnetic field curve, so as to adopt a differential structure (as shown in Figure 2(b)), and the bias field The size of H _b can be changed by adjusting the distance from permanent magnet 7 to probes 1 and 2; due to the existence of bias field H _b , probes 1 and 2 are equivalent to the equivalent magnetic field reduction of probe 1 when the magnetic field H _i generated by the induced current The smaller is H _b -H _i , and the equivalent magnetic field of the probe 2 is increased to be H _b +H _i . The advantage of the differential structure is that it nearly doubles the amplified signal, improves the signal-to-noise ratio, and improves the linearity of the output curve; and the biggest advantage of this sensor structure is that the sensor and the circuit under test can work without affecting each other. Therefore, the utility model provides a reliable method for non-contact measurement of current in various fields of production and scientific research.

The same oscillation and rectification circuits 3 and 4 provide sinusoidal AC signals for the probes 1 and 2 respectively. Take any oscillation and rectification circuit 3 as an example (as shown in Figure 3), it is made of Corbitz oscillation circuit 11, preamplifier circuit 12 and rectification circuit 13; The signal amplified by the preamplifier 12 is connected to the rectification circuit 13 by the output terminal, and the rectification circuit 13 converts the high-frequency AC signal into a DC signal output U ₁ and U ₂ with twice the peak value of the AC signal; the entire sensor probe 1, 2 and the oscillation And the rectifier circuit 3, 4 is wrapped with a non-ferromagnetic metal shell or a resin coat. Then the differential output voltage signal U=U ₂ -U ₁ of the two oscillation and rectification circuits 3 and 4 is processed by the zero-adjustment amplifier circuit 5 and then connected to the digital display 6, (as shown in Figure 6) to directly display the current measurement data function.

Because the utility model adopts the Co-based amorphous strip with a larger GMI rate, the size of the bias magnetic field can be set by adjusting the distance from the permanent magnet 7 to the two probes 1, 2, that is, the GMI rate of the probe varies with the magnetic field The working point on the curve; the design adopts a dual-probe differential structure, which can amplify the signal, improve the signal-to-noise ratio, and improve the linearity of the output curve; and the sensor is a non-contact current measurement, and its measurement range is 0-10A. The utility model has the advantages of simple electronic circuit, novel and compact structure, economy, convenience and practicality, and can be widely used in current measurement in various fields of production and scientific research.

Description of drawings

Figure 1: Structural diagram of array type giant magneto-impedance (GMI) effect current measurement sensor;

Figure 2(a): Schematic diagram of the utility model array probe structure;

Figure 2(b): Structure diagram of bias field and probe setup;

Figure 3: a schematic diagram of any group of probes and oscillation and rectification circuits in the utility model;

Figure 4: GMI ratio curve of CoFeSiB amorphous ribbons versus magnetic field;

Figure 5: Schematic diagram of the output waveform of the oscillation and rectification circuit;

Figure 6: The output variation curve of the signal U with the current under different bias magnetic fields;

Figure 7: Schematic diagram of the zero-setting amplifier and digital display of the present invention.

As shown in Figure 1, 1 and 2 are the same array current sensor probes; 3 and 4 are the same oscillation and rectification circuits; 5 is the zeroing amplifier circuit; 6 is the digital display device; 7 is the permanent magnet; Measuring current copper wire;

As shown in Figure 2, the array type current sensor probes 1 and 2 are connected in series by amorphous strip units 8, wherein 9 is a copper wire; side;

As shown in Figure 3, the oscillation and rectification circuits 3 and 4 are composed of the same Corbitz oscillation circuit 11, preamplifier circuit 12 and rectification circuit 13;

As shown in Figure 7, it is a zeroing amplifier circuit 5 and a digital display device 6;

Detailed ways

Example 1:

Among Fig. 2, 1,2 are array type current sensor probes, and 7 is permanent magnet (as ferrite, rubidium iron boron etc.,), with block (cuboid) ferrite in the concrete example. 8 is an amorphous strip unit, 9 is a copper wire, and 10 is a copper wire passing a current to be measured.

Array current sensor probes 1 and 2 are respectively welded in series by 16 rectangular amorphous strip units 8 with good soft magnetic properties and copper wires 9. The amorphous strip unit 8 is 10mm long, 2.5mm wide, and 30um thick. The distance between each amorphous strip unit is 1 mm, and the requirements for the two array probes 1 and 2 are the same. The two array probes 1, 2 are placed symmetrically on both sides of the conducting wire 10. When the current passes through the wire 10, a ring magnetic field H _i is generated around the wire. The output voltage signals of the probes 1 and 2 can reflect the average GMI effect of the amorphous strip unit 8 .

The amorphous strip unit 8 is a CoFeSiB amorphous strip (Co ₆₈ Fe ₄ Si ₁₂ B ₁₆ , the specific material name must be listed in the embodiment!), and at a working frequency of 3.5792MHz, the maximum giant magnetoimpedance change rate can reach 210 % (see Figure 4). In addition, the permanent magnet 7 is used to provide the bias magnetic field _Hb , which is used to fix the working points of the array probes 1 and 2 on the GMI rate versus magnetic field curve, so as to adopt a differential structure, see Figure 2(b) and Figure 4 , the ordinate mir in Figure 4 is the GMI rate, the specific expression:

$\mathrm{<span\; class="notranslate">\; the\; mirror</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; \%</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; sat</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}{\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; sat</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Wherein, Z(H) is the AC impedance value of the amorphous ribbon unit 8 under any magnetic field, and Z(H _sat ) is the AC impedance value of the amorphous ribbon unit 8 after magnetization to saturation. The size of the bias field H _b can be changed by adjusting the distance from the permanent magnet 7 to the probes 1 and 2. Due to the existence of the bias field H _b , the probe 1 is equivalent to an equivalent magnetic field H when the magnetic field H _i generated by the induced current is ₁ ＝H _b -H _i , and the equivalent magnetic field of probe 2 is H ₂ ＝H _b +H _i , so the GMI effect caused by H _i can be doubled, so that the output signal of the probe is amplified and the output curve is linear Accuracy is also improved; since the differential structure probes 1 and 2 are identical, interference from factors such as temperature drift can be eliminated, and the signal-to-noise ratio can be improved.

Example 2:

In FIG. 3 , 1 is an array current sensor probe, 11 is a Colpitts oscillation circuit, 12 is a preamplifier circuit, and 13 is a rectification circuit. 14 is the starting capacitor C ₃ , 15 is the crystal oscillator, 16 and 17 are two voltage divider resistors with equal resistance, 18 is the feedback capacitor C ₁ , 19 is the feedback capacitor C ₂ , 20 is the transistor, and 21 is the emitter current limiting resistor , 22 is a high-frequency operational amplifier, 23 and 34 are two rectifier diodes, 25 is a stabilizing capacitor, and 26 is a filter capacitor.

The power supply voltage Vcc of the Corbitz oscillation circuit 11 can be 12V, and the static operating point of the base of the transistor 20 is designed to be stable. Since the resistance values of the two divider resistors 16 and 17 are equal, the static operating voltage of the base of the transistor 20 is 6V. , the static working voltage of the transistor 20 emitter is stable at about 5.3V; the array probe 1 uses CoFeSiB (Co ₆₈ Fe ₄ Si ₁₂ B ₁₆ ) amorphous material, which is connected to the circuit as a part of the emitter load and the emitter current limiting resistor 21, The emitter current-limiting resistance 18 is 390Ω; the Corbitz oscillating circuit 11 stabilizes the frequency and oscillates, and the oscillation frequency is the frequency 3.5795MHz of the crystal oscillator 15; the feedback capacitor 18 and the feedback capacitor 19 are adjusted to make the emitter output a stable sinusoidal signal, and the array probe 1 is due to There is a large AC impedance and a certain AC voltage signal is generated at both ends.

When there is no external current to generate a magnetic field to act on the array probe 1, the AC impedance value of the array probe 1 will not change, and the AC voltage signal on it is the stable sinusoidal output of the emitter of the transistor 20 in the Corbitz oscillation circuit 11. signal, the AC voltage signal is amplified by the preamplifier circuit 12 formed by the high-frequency operational amplifier 22, and the amplified AC signal U _p1 (corresponding to the solid line waveform part of the a and c diagrams in Figure 5) is connected to two rectifiers The rectification circuit 13 composed of diodes 23 and 24 converts the high-frequency AC signal U _p1 into a DC signal U ₁ having twice the peak value of the AC signal U _p1 .

The structure and working principle of the array probe 2 and the oscillation and rectification circuit 4 on the other side of the differential structure are the same as those described above. When there is no external current to generate a magnetic field to act on the array probe 2, the AC impedance value of the array probe 2 will not change, and the AC voltage signal on it is the stable sinusoidal output of the transistor 20 emitter in the Corbitz oscillation circuit 11. signal, the amplitude of the AC voltage signal is amplified by the amplifier and the signal is U _p2 (corresponding to the solid line waveform part of c and d in Figure 5), and the output signal after rectification is U ₂ , where U ₂ is the AC signal U _p2 double the peak value. See Figure 5 for details, where the solid-line waveforms in (a) and (c) are respectively the waveforms U _p1 and U _p2 of the AC signals on probes 1 and 2 amplified by the amplifier, while the waveforms in (b) and (d) The solid-line waveforms are the rectified outputs U ₁ and U ₂ respectively.

According to the working principle of the probe described in this patent, (see Figure 2(b) and Figure 4) due to the existence of the bias field _Hb , when the magnetic field generated by the current to be measured acts on the probes 1 and 2, the The AC voltage signal will increase and decrease with their impedance values respectively, so that the AC signals at both ends of the probe 1 and 2 will increase or decrease. Correspondingly, the amplified waveform U _p1 , U _p2 and the rectified output U ₁ , U ₂ also changes accordingly, as shown in the waveforms shown by the dotted lines in each figure in Fig. 5.

As shown in Figure 6, within the measurement range of 0-5A current passing through the wire, the output variation curve of the signal U with the current under different bias magnetic fields _Hb , through experiments and considering the size of the sensor (permanent magnet 7 to Probe 1, 2 distance), the best working range of the bias magnetic field H _b is 10 ~ 20Oe.

As shown in Fig. 6, when the bias field H _b generated by the permanent magnet 7 is set, we can obtain the linear relationship between the current I to be measured in the wire 10 and the measured U value:

U=KI+U _b (3)

Among them, K(V/A) is the proportional constant of the measured current I and the measured U value, that is, the slope of the straight line in Figure 5, which is a negative value; U _b is the initial value of U when the measured current I is 0.

Example 3:

An embodiment of the data of each part of the circuit element is given.

In FIG. 3 , the transistor 20 uses a 2SC1815 high-frequency transistor, and its cut-off frequency f _T is five times higher than the frequency of the crystal oscillator 15 . The frequency of the crystal oscillator 15 is above 1 MHz, and the starting capacitor 14 is 15 pF˜10 nF, which can start the oscillation. The two voltage dividing resistors 16 and 17 can be selected as 10kΩ; the injector current limiting resistor 21 is 390Ω; the feedback capacitor 18 is 1000pF-2200pF, the feedback capacitor 19 is 60pF-200pF, and the ratio of the feedback capacitor 18 to the feedback capacitor 19 is 2 to 25 between. The oscillating frequency of the Corbitz oscillating circuit is the frequency of the crystal oscillator 15 .

The preamplifier circuit 12 in Fig. 3 should select a high-frequency operational amplifier whose gain-bandwidth product GBP is more than 5 times the frequency of the crystal oscillator 15 and whose offset voltage is less than 4mV. LM318 can be selected for high-frequency operational amplifier 22

In the rectifier circuit 3 in FIG. 3 , the rectifier diodes 23 and 24 are Schottky diodes.

Example 4:

In Fig. 7, 6 is a digital display, 27, 28 are amplifiers with low offset voltage. The amplifier formed by 27 can isolate the signal U=U ₂ -U ₁ from the following circuit to eliminate mutual interference; the inverse proportional zeroing output amplifier formed by the operational amplifier 28; the above two parts constitute the follow-up zeroing Amplifier 5, whose output is U _o .

The relationship between the signal U and the final output voltage U _o after the subsequent zero-adjustment amplifier circuit 5 is:

U _o ＝A(UU _f ) (4)

Wherein, A is the amplification factor of the inverse proportional circuit formed by the operational amplifier 28, which is a negative value; U _f is the reference voltage. Then the linear relationship (3) between the measured current I and the measured U value in the wire 10 obtained in Example 2 is substituted into (4) formula to obtain the final output voltage _U between the measured current Relationship:

U _o ＝AKI+A(U _b -U _f ) (5)

In the case of no current to be measured, the reference voltage U _f is adjusted after stabilization so that U _f is equal to U _b , then the final output voltage value U _o of the zero-adjustment output amplifier 28 is 0 when there is no current. The adjustment of the reference voltage U _f can be realized by dividing the voltage with the potentiometer in the standard power supply (5V). Then adjust the amplification factor A of the inverse proportional circuit formed by operational amplifier 28, so that the value of AK (V/A) is equal to 1, so the relationship between the final output voltage _Uo and the current to be measured is:

U _o = I (6)

The final output voltage U _o is then connected to the digital display 6, and the voltage value of U _o displayed on the digital display 6 is equal to the current value to be measured, so that the sensor can directly achieve the function of current measurement.

In Fig. 7, amplifiers 27 and 28 with low offset voltage can choose op-07;

In Fig. 7, digital display 6 can use ZF5135 digital panel meter.

Claims (8)

1. The array type giant magneto-impedance effect current sensor consists of array type amorphous current sensor probes (1), (2), oscillation and rectification circuits (3), (4), subsequent zeroing amplifiers (5), and digital displays ( 6) Composition; It is characterized in that: (1) Array type current sensor probes (1), (2) are welded in series by a plurality of rectangular amorphous strip units (8) with good soft magnetic properties and copper wires (9), and the two array type probes (1), (2) require the same, and it is placed on both sides of the energized wire (10) in parallel and symmetrically; (2) A permanent magnet (7) is provided below the energized wire (10), through which a bias magnetic field is provided to fix the array probe (1), (2) to work on the GMI rate of the amorphous strip material with the magnetic field variation curve In order to adopt a differential structure, the size of the bias magnetic field is determined by the magnetic field strength of the permanent magnet (7) and the distance from the permanent magnet (7) to the probes (1), (2); (3) Oscillating and rectifying circuits (3), (4) are all made up of Corbitz oscillating circuit (11), preamplifier circuit (12) and rectifying circuit (13), and Corbitz oscillating circuit (11) provides high frequency AC signal, the input terminal of the preamplifier circuit (12) is connected to both ends of the amorphous band unit (8), and the signal at both ends of the amorphous band unit (8) amplified by it is connected to the rectifier circuit (13) by the output terminal, The rectification circuit (13) converts the high-frequency AC signal generated by the amorphous strip into DC signals U ₁ , U ₂ with twice the peak value of the AC signal; (4) The above-mentioned DC signals U ₁ and U ₂ are connected to the zero-adjustment output amplifier (5), and then sent to the digital display (6) after calculation and zero-adjustment to measure the current I to be measured. 2. the array type giant magneto-impedance effect current sensor as claimed in claim 1 is characterized in that: Corbitz oscillating circuit (11) is to be made of transistor (20) that cut-off frequency is 3～60MHz, and its base pole and DC power supply The resistance values of the two voltage dividing resistors (16) and (17) between V _cc and between the base and the ground are equal; the crystal oscillator (15) and the starting capacitor (14) with a frequency of 1-20 MHz are connected in series at the base Between the electrode and the ground; one end of the probe (1) is grounded, and the other end is connected in series with the load resistor (21) to the emitter of the transistor, and the probe (1) exists as a part of the emitter load. 3. The array type giant magneto-impedance effect current sensor as claimed in claim 1, characterized in that: the array type current sensor probes (1), (2) are made of 4 to 30 rectangular amorphous strips with good soft magnetic properties The unit (8) is welded in series by copper wires (9). The length of the amorphous strip unit is 5-25mm, the width is 0.5-10mm, and the thickness is 10um-40um. The distance between the two amorphous strip units is 0.5-10mm; an array of probes (1), (2) symmetrically placed on both sides of the live wire (10), the distance from the wire to the array sensor probe is 1-20 mm. 4. The array type giant magneto-impedance effect current sensor as claimed in claim 1, characterized in that: the amorphous band unit (8) adopts a Co amorphous band or a Fe-based nanometer with a giant magneto-impedance rate of change greater than 30%-50%. Thin strips of crystalline material. 5. The array type giant magneto-impedance effect current sensor according to claim 4, characterized in that: the amorphous strip unit (8) is CoFeSiB amorphous material. 6. The array type giant magneto-impedance effect current sensor as claimed in claim 1, characterized in that: use ferrite or NdFeB permanent magnet (7) to provide bias magnetic field _Hb , and the bias field range is 10～30Oe . 7 . The array type giant magneto-impedance effect current sensor according to claim 6 , wherein the working range of the bias magnetic field H _b is 10-20 Oe. 8. The array type giant magneto-impedance effect current sensor according to claim 1, characterized in that: the frequency range of said crystal oscillator (15) is 2-5 MHz.

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