CN100516919C

CN100516919C - Three terminal type magnetic flow gate sensor

Info

Publication number: CN100516919C
Application number: CNB2005100282899A
Authority: CN
Inventors: 顾伟; 张松勇
Original assignee: Shanghai Maritime University
Current assignee: Shanghai Maritime University
Priority date: 2005-07-29
Filing date: 2005-07-29
Publication date: 2009-07-22
Anticipated expiration: 2025-07-29
Also published as: CN1904629A

Abstract

The invention relates to a three-terminal flux gate sensor that is made up of coiling a set of winding on two I shaped frames, and one starting end of the winding is connected to the terminal end of the other winding to form center end to used as the measuring end and feedback end of the sensor. The two other ends of the winding are used as the prompting end. The three terminals are sintered on PCB, and the two I shaped frame winding are cementing to form II shaped frame winding. Coiling 2-4 circles of permalloy to the center of two I shaped frames to make raceway magnetic core, and packaging the II shaped frame magnetic winding and PCB into non magnetic aluminum box. The invention has simple structure, and easy to manufactured. It could counteract the influence of distributed capacitance, interference signal and temperature drifting. The accuracy and resolution of the sensor are improved. And the power consumption and temperature coefficient would be decreased.

Description

Three terminal type magnetic flow gate sensor

Technical field

The present invention relates to a kind of sensor of measuring low-intensity magnetic field.

Background technology

The fluxgate sensor that uses at present low-intensity magnetic field being detected, its structure generally adopts runway to mould the permalloy sheet of the built-in similar shape of material housing as magnetic core, tight one group of runway shape of uniform winding Magnetic Measurement coil on housing, two exits of coil are as measuring junction.Then the runway shape magnetic coil that winds is inserted in the center pit of " I " font bakelite skeleton, tight one group of drive coil of uniform winding on " I " font bakelite skeleton at last, two exits of coil are as the excitation end.After encapsulation, make four end formula runway shape fluxgate sensors.Detect when using, four end formula runway shape sensors are placed the measured position, magnetic field, the magnetic core direction is over against tested magnetic direction.Add driving voltage at excitation end, then at measuring junction voltage signal is just arranged, its second harmonic be directly proportional by measuring magnetic field, through oversampling circuit conditioning and demarcation, finally can record by the induction level of measuring magnetic field.Four end formula runway shape fluxgate sensors are when processing and fabricating, and its punching coiling of measuring coil is very inconvenient, and driving voltage requires Frequency and Amplitude Stabilization, encourage power consumption big, and the sensor symmetry is poor, noise is relatively poor, temperature drift is big.Thereby limited its further expansion in the weak magnetic survey field.Its key technical indexes is:

Measurement range: ± 1nT～± 100000nT;

2. noise: 1nT;

3. resolution: 1nT;

4. precision:＜± 1%F.S.;

5. the linearity: ± 0.5%F.S.;

6. zero shift:＜2nT/h;

7. zero-bit temperature drift:＜20nT/ ℃;

8. power consumption:＜200mW.

Summary of the invention

The object of the present invention is to provide a kind of three terminal type magnetic flow gate sensor.Structurally adopt one group of series connection coiling, center tap is as measuring junction, and also as feedback end, two ends are as the excitation end in addition.So this group coil plays excitation, measures and feeds back three kinds of effects.Make that sensor construction is simple, processing and fabricating is convenient.Because the coil turn on center tap both sides is identical, resistance equates, inductance equates, just can offset interference, reduces noise.And its resolution, measuring accuracy, stability and temperature performance also be improved largely, thereby expanded the range of application of fluxgate sensor in weak magnetic detection range, improved the corresponding techniques indication range.

The present invention is achieved in that with identical processing technology tight separately one group of coil of uniform winding on two " I " font ceramic skeletons, the end of the top of one group of coil wherein and another group is connected as center-side draws, this center-side is exactly the measuring junction and the feedback end of sensor, and the excitation end as sensor is drawn at the other two ends of above-mentioned two groups of coils respectively, and three ends that will draw are welded on the printed circuit board (PCB) connection terminal when using as sensor." I " font ceramic skeleton behind above-mentioned two coilings sticks into the whole shaped framework coil of " II " font, utilizes the center square hole of two " I " font ceramic skeletons, and laminated string is made track-shaped magnetic core around 2 to 4 layers of 1J86 permalloy tape.Like this, again that coiling is good " II " font magnetic core coil and printed-wiring board (PWB) place in the non magnetic aluminum box, are packaged into one with silica gel.

Description of drawings

Fig. 1 is a structure cut-open view of the present invention.

Fig. 2 is a circuit diagram of the present invention.

When Fig. 3 uses for the present invention and the connecting circuit figure of isolation coupling adapter T.

Embodiment

Below in conjunction with accompanying drawing the present invention is described in further detail.

Referring to Fig. 1,1,6 is " I " font ceramic skeleton, and 14,7 is tight uniform winding two groups of first, second coils on skeleton 1,6, and the enameled wire of using φ 0.1 is around 800～1000 circles, and coil winding-direction as shown by arrows.13 is the top of

first coil

14, and 11 is the end of second coil 7.The top of the end of first coil 14 and second coil 7 connects into center-side 4.3,12 is two bonding places of " I " font ceramic skeleton 1 and 6, forms the coil assembly of " II " font skeleton.2,5 center pits that are respectively " I " font ceramic skeleton 1,6 are made track-shaped magnetic core 8 with 1J86 permalloy tape laminated string in center pit 2,5 around 2 to 4 circles.10 is non magnetic aluminum box, is used for placing " II " font magnetic core skeleton and coil.9 is the threaded hole of aluminium box 10 bottom surfaces, is used to install and fix sensor.The top 13 of first coil 14, the end 11 of coil 7, and three extension lines that the top of the end of first coil 14 and second coil 7 connects into center-side 4 are welded on the printed-wiring board (PWB), cover plate as aluminium box 10 is packaged into sensor integral body with " II " font magnetic core skeleton and coil with silica gel.The top 13 of first coil 14 of drawing on the printed-wiring board (PWB) and the end 11 of second coil 7 are as the excitation end of three terminal type magnetic flow gate sensor of the present invention, and the top of the end of first coil 14 and second coil 7 connects into measuring junction and the feedback end of center-side 4 as sensor of the present invention.The circuit diagram of three terminal type magnetic flow gate sensor is seen Fig. 2.

When the low-intensity magnetic field of carrying out three terminal type magnetic flow gate sensor of the present invention detects, sensor is placed in the detected magnetic field environment, the magnetic core direction and the tested magnetic direction of sensor are consistent.Referring to Fig. 3, T is the isolation coupling adapter, A, the B end that the square wave of the 5KHz that produces by exciting circuit (also can sine wave or triangular wave etc.) is input to isolation coupling adapter T converts the two-way square wave to, be input to 11,13 excitation ends of three terminal type magnetic flow gate sensor of the present invention by C, D end, so produce the electric signal that characterizes magnetic field at measuring junction 4, extract the second harmonic component that this electric signal is directly proportional with magnetic field, handle and demarcate through modulate circuit, just can obtain the magnetic induction density of detected magnetic field in this position.Isolation coupling adapter T is placed in the weak magnetic field measurement instrument modulate circuit, is connected with sensor electrical, and this adapter T can match on market.

Three terminal type magnetic flow gate sensor of the present invention after measured, its technical indicator is:

Measurement range: ± 0.1nT～± 1000000nT;

2. noise:＜0.5nT;

3. resolution: 0.5nT;

4. precision:＜± 1%F.S.;

5. the linearity: ± 0.5%F.S.;

6. zero shift:＜1nT/h;

7. zero-bit temperature drift:＜0.5nT/ ℃;

8. power consumption:＜50mW.

To be measurement, feedback and drive coil by the coil of two groups of same process coileds be connected in series the characteristics of three terminal type magnetic flow gate sensor of the present invention end to end forms one group of coil, and organize measuring junction, the feedback end of the center-side of coil as sensor by this, two ends of coil are as the excitation end of sensor.The magnetic core coil that coil by two coilings on " I " font ceramic skeleton is bonded into " II " font skeleton has advantage simple in structure, easy to process, and two groups of coil turns, resistance value, inductance value, distributed capacitance after the process screening all equate, so just can suppress to disturb (comprising the fundametal compoment in the detected electric signal of measuring junction), thereby noise, zero-bit temperature drift, power consumption have been effectively reduced, improved resolution, precision, stability and interference free performance, expanded the range of application of fluxgate sensor at weak magnetic detection range.

The present invention can be widely used in fields such as space flight navigation, geologic prospecting, naval vessel demagnetization, metering safety check.

Claims

1. three terminal type magnetic flow gate sensor, comprise two " I " font ceramic skeletons (1,6), closely uniform winding is at skeleton (1,6) last two groups of coils (14,7), printed circuit board (PCB) and non magnetic aluminum box (10), it is characterized in that: the top of the end of first coil (14) and second coil (7) connects into center-side (4), measuring junction and feedback end as sensor, the top (13) of first coil (14) and the end (11) of second coil (7) are as the excitation end of sensor, coil uses identical processing technology to twine the coil turn on center tap both sides, resistance value, inductance value, distributed capacitance all equates.

2. three terminal type magnetic flow gate sensor according to claim 1 is characterized in that: two groups of coils (14,7) are gone up tight uniform winding 800～1000 circles by the enameled wire in Ф 0.1 line footpath at two " I " font ceramic skeletons (1,6) respectively.

3. three terminal type magnetic flow gate sensor according to claim 1 and 2 is characterized in that:

(3,12) are bonded to the whole shaped framework coil of " II " font through the bonding place for a, two " I " font coil racks (1,6);

Among the b, two " I " font coil rack center pits (2,5) with the laminated string of 1J86 permalloy tape around 2～4 circles as track-shaped magnetic core (8).

4. three terminal type magnetic flow gate sensor according to claim 1 is characterized in that:

The top of the end of a, first coil (14) and second coil (7) connects into center-side (4), the top (13) of first coil (14) and the end (11) of second coil (7) are drawn respectively and are welded on the printed circuit board (PCB) connection terminal when using as sensor;

B, two " I " font skeletons (1,6) and coil (14,7) place non magnetic aluminum box (10), and printed circuit board (PCB) is packaged into sensor integral body as the cover plate of aluminium box (10) with silica gel.