CN117192447A - Magneto-sensitive element, method for measuring external magnetic field by using magneto-sensitive element and magnetic sensor - Google Patents
Magneto-sensitive element, method for measuring external magnetic field by using magneto-sensitive element and magnetic sensor Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 21
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- 230000035699 permeability Effects 0.000 claims abstract description 14
- 238000004804 winding Methods 0.000 claims abstract description 10
- 230000008859 change Effects 0.000 claims abstract description 9
- 230000005284 excitation Effects 0.000 claims description 53
- 230000005415 magnetization Effects 0.000 claims description 27
- 230000006698 induction Effects 0.000 claims description 8
- 239000000696 magnetic material Substances 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 230000001788 irregular Effects 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 239000010941 cobalt Substances 0.000 claims description 4
- 229910017052 cobalt Inorganic materials 0.000 claims description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 4
- 229910000531 Co alloy Inorganic materials 0.000 claims description 3
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 claims description 3
- QVYYOKWPCQYKEY-UHFFFAOYSA-N [Fe].[Co] Chemical compound [Fe].[Co] QVYYOKWPCQYKEY-UHFFFAOYSA-N 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 4
- 238000005259 measurement Methods 0.000 abstract description 2
- 239000011162 core material Substances 0.000 description 147
- 230000004907 flux Effects 0.000 description 18
- 238000010586 diagram Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000010030 laminating Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
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Abstract
The invention provides a magneto-sensitive element, a method for measuring an external magnetic field by using the magneto-sensitive element and a magnetic sensor. The magneto-sensitive element comprises a first magnetic core and a second magnetic core, wherein the first and second coils are provided with the same number of turns, the same magnetic path length and opposite winding directions, the magnetic permeability of the first and second magnetic cores is equal, the areas of the sections of the first and second magnetic cores perpendicular to the magnetic path direction are equal, under the action of exciting currents I (t) with the same magnitude and opposite directions, the first and second coils generate magnetic fields, and when the exciting currents are in +I s to-I s When the interval is changed, the magnetic field strength is +H s to-H s The interval changes, and the B-H characteristic curves of the first magnetic core and the second magnetic core respectively have linear change intervals. The element has simple structure, reduced requirement for magnetic core, reduced cost, and the first and second magnetic cores respectively work in the linear region during actual measurement, and the applied inductance value of the two coils is obtained by measuringIs simple and easy to operate, and can improve the detection accuracy.
Description
Technical Field
The invention belongs to the technical field of magnetic sensing, and particularly relates to a magnetic sensor, a method for measuring an external magnetic field by using the same and a magnetic sensor.
Background
A magnetic sensor is a functional device that senses changes in magnetic signals. The technical principles of the magnetic sensor include Hall principle, fluxgate principle, wiegand effect, giant magneto-resistance effect, tunnel magneto-resistance effect and the like.
Magneto-sensitive elements are important elements in magnetic sensing for sensing a measured magnetic field. The inductance coil formed by winding the magnetic core is a commonly used magnetic sensor, magnetic field information is obtained by measuring inductance, but as inductance values are closely related to materials, structures, shapes, sizes and the like of the magnetic core, small changes of the factors can possibly cause the magnetic core to change the induction capacity of the magnetic field, so that the magnetic core is required to have strict requirements in practical application, the magnetic core is required to have consistent structure and consistent shape and size, and the manufacturing difficulty and cost of the magnetic core are greatly increased.
Disclosure of Invention
Aiming at the state of the art, the invention provides a magnetic sensor comprising a magnetic core and a coil, which can reduce the requirements on the structure, the shape and the size of the magnetic core, thereby greatly reducing the manufacturing difficulty and the cost of the magnetic core, and the method for measuring the external magnetic field by using the magnetic sensor is simple and easy to implement.
The technical scheme provided by the invention is as follows: a magneto-sensitive element comprises a first magnetic core, a first coil and a second magnetic core, wherein the first coil and the second magnetic core are wound around the periphery of the first magnetic core, the second coil is wound around the periphery of the second magnetic core, and the winding direction of the first coil is opposite to the winding direction of the second coil; the external circuit is respectively connected with the two ends of the first coil and the two ends of the second coilFor providing exciting currents I (t) with the same magnitude and opposite directions for the first coil and the second coil to generate an exciting magnetic field H Excitation ；
Under the action of exciting current I (t), the first coil generates magnetic field, the relation between the magnetic flux and exciting current is shown in FIG. 1, and the relation between the inductances at two ends of the first coil and exciting current is shown in FIG. 2, i.e. exciting current is +I s to-I s When the interval changes, the magnetic flux phi is unsaturated and linearly changes, and the two ends of the first coil generate constant inductance value L 1 The method comprises the steps of carrying out a first treatment on the surface of the The fitted hysteresis loop is shown in FIG. 3 when the first core is in the magnetic field, i.e. the first core has an ideal B-H characteristic curve in the magnetic field when the exciting current is +I s to-I s When the interval is changed, the magnetic field strength is +H s to-H s The magnetic induction intensity of the first magnetic core is unsaturated and linearly changed due to interval change, namely the first magnetic core does not reach a magnetization saturation state, +H s to-H s Is called a magnetization linear section in which a constant inductance value is generated at both ends of the first coil;
under the action of exciting current I (t), the second coil generates magnetic field, the relation between the magnetic flux and exciting current is shown in figure 1, the relation between the inductances at two ends of the second coil and exciting current is shown in figure 2, namely, the exciting current is at +I s to-I s When the interval changes, the magnetic flux phi is unsaturated and linearly changes, and the two ends of the second coil generate constant inductance value L 2 The method comprises the steps of carrying out a first treatment on the surface of the The fitted hysteresis loop is shown in FIG. 3 when the second core is in the magnetic field, i.e. the second core has an ideal B-H characteristic curve in the magnetic field when the exciting current is +I s to-I s When the interval is changed, the magnetic field strength is +H s to-H s The magnetic induction intensity of the second magnetic core is unsaturated and linearly changed due to interval change, namely the second magnetic core does not reach a magnetization saturation state, +H s to-H s The interval of (2) is called a magnetization linear interval, and a constant inductance value is generated at two ends of the second coil in the magnetization linear interval;
the number of turns of the first coil is equal to the number of turns of the second coil, and the turns of the first coil and the turns of the second coil are N;
the magnetic permeability of the first magnetic core is equal to that of the second magnetic core and is mu e ；
The first magnetic core has uniform overall shape, i.e. the areas of the sections perpendicular to the magnetic path direction (called effective sectional areas) in the first magnetic core are equal to each other, and are S e1 ；
The second magnetic core has uniform overall shape, i.e. the areas of the sections perpendicular to the magnetic path direction (called effective sectional areas) in the second magnetic core are equal to each other, and are S e2 ；
The magnetic path length of the first coil is equal to that of the second coil, and the magnetic path lengths are l e 。
The magnetic sensor can obtain external magnetic field information, and comprises the following steps:
firstly, the magneto-sensitive element is placed in an environment without an external magnetic field, and an excitation magnetic field H is generated under the condition that excitation current I (t) with the same size and opposite directions is provided for a first coil and a second coil through an external circuit Excitation Ensure H Excitation Is positioned in the magnetization linear section and measures the inductance L at the two ends of the first coil 1 Inductance L at two ends of the second coil 2 ；
Then, the magneto-sensitive element of the invention is placed in an applied external magnetic field H Outer part In the environment of (1), the external circuit simultaneously provides exciting current I (t) for the first coil and the second coil which are the same in size and opposite in direction to generate an exciting magnetic field H Excitation Ensure H Excitation +H Outer part Is positioned in the magnetization linear section, and the inductance L 'at the two ends of the first coil is measured' 1 Inductance L 'with both ends of the second coil' 2 ；
External magnetic field H Outer part Can be of the size of L 1 、L 2 、L′ 1 、L′ 2 The preparation method comprises the following steps:
when the cross section area S of the first magnetic core e1 Cross-sectional area S with the second magnetic core e2 When equal，
The method comprises the following steps:
in the present invention, formula (1) is overThe symbols in (a) are as follows:
i (t) represents the excitation current as a function of time;
n represents the number of turns of the first coil, i.e. the number of turns of the second coil;
l e representing the magnetic path length of the first magnetic core, i.e. the magnetic path length of the second magnetic core;
μ e representing the magnetic permeability of the first magnetic core, i.e. the magnetic permeability of the second magnetic core;
H excitation Representing the strength of the magnetic field generated when the exciting current acts on the coil;
H outer part Representing the strength of the applied external magnetic field;
b represents magnetic induction intensity;
Φ represents magnetic flux;
l represents the inductance value of the two ends of the coil under the action of exciting current, and the inductance value of the first coil is recorded as L 1 The inductance value of the second coil is denoted as L 2 ；
L' represents the exciting current and the external magnetic field H Outer part Simultaneously, the inductance values at the two ends of the coil are acted, and the inductance value of the first coil is recorded as L' 1 The inductance value of the second coil is denoted as L' 2 。
Cross-sectional area S of first magnetic core e1 Cross-sectional area S with the second magnetic core e2 Equal, i.e. S e1 ＝S e2 ＝S e Time of day
(1) The exciting current I (t) acts on the first coil and the second coil respectively, and no external magnetic field H exists Outer part When acting on the first coil and the second coil:
N·I(t)＝H excitation ·l e ①
B＝μ e ·H Excitation ②
From (1) and (2), it is possible to obtain:
and Φ=n·b·s e ④
From (3) and (4), it is possible to obtain:
whereas Φ=l·i (6)
From (5) and (6), it is possible to obtain:
the inductance values of the first coil and the second coil can be deduced:
(2) The exciting current I (t) acts on the first coil and the second coil respectively, and the external magnetic field H Outer part When acting on the first coil and the second coil
The first magnetic core is excited by exciting current I (t) and external magnetic field H Outer part Still working in the magnetization linear region under the combined action of (2), so that the magnetic permeability is unchanged;
the second magnetic core generates a magnetic field H under the excitation current I (t) Outer part Still working in the magnetization linear region under the combined action of (2), so that the magnetic permeability is unchanged;
in the external magnetic field H due to the opposite direction of the first coil and the second coil Outer part Under the action of the magnetic field, the direction of the exciting magnetic field of the first group of coils in the first coil and the second coil is the same as the direction of the external magnetic field, so that the magnetic flux in the magnetic core is increased, the other coil isThe direction of the exciting magnetic field of the group coil is opposite to the direction of the external magnetic field so as to reduce the magnetic flux in the magnetic core, and the direction of the exciting magnetic field of the second coil is opposite to the direction of the external magnetic field on the assumption that the direction of the exciting magnetic field of the first coil is the same as the direction of the external magnetic field, (2) the exciting magnetic field of the second coil can be changed as follows (9) or (2)
B＝μ e ·(H Excitation +H Outer part ) ⑨
B＝μ e ·(H Excitation -H Outer part ) ⑩
The inductance values of the first coil and the second coil under the action of an external magnetic field are respectively obtained by the joint deduction of the (1), the (4) and the (6):
from the following componentsAnd->The method can be calculated as follows:
substituting (8)It can be derived that:
from the formulaIt can be seen that if the number of turns, the magnetic path length, the sectional area, the input signal and other parameters of the first coil and the second coil are all fixed, the external magnetic field H Outer part The inductance value of the two groups of coils under the action of the external magnetic field or not can be calculated.
(II) effective cross-sectional area S of first magnetic core e1 Effective cross-sectional area S with the second magnetic core e2 Inequality S e S, i.e e1 ≠S e2 Time of day
(1) The exciting current I (t) acts on the first coil and the second coil respectively, and no external magnetic field H exists Outer part When acting on the first coil and the second coil
From the joint deductions of (1) (2) (4) (6):
(2) The exciting current I (t) acts on the first coil and the second coil respectively, and the external magnetic field H Outer part When acting on the first coil and the second coil
The first magnetic core is excited by exciting current I (t) and external magnetic field H Outer part Still working in the magnetization linear region under the combined action of (2), so that the magnetic permeability is unchanged;
the second magnetic core is excited by the alternating exciting current I (t) and the external magnetic field H Outer part Still working in the magnetization linear region under the combined action of (2), so that the magnetic permeability is unchanged;
in the external magnetic field H due to the opposite direction of the first coil and the second coil Outer part Under the action of the magnetic field, the direction of the exciting magnetic field of one group of coils in the first coil and the second coil is the same as the direction of the external magnetic field, so that the magnetic flux in the magnetic core is increased, the direction of the exciting magnetic field of the other group of coils is opposite to the direction of the external magnetic field, so that the magnetic flux in the magnetic core is reduced, and the exciting magnetic field in the first coil is the same as the direction of the external magnetic field, so that the exciting magnetic field in the second coilThe direction of the exciting field is opposite to the direction of the external magnetic field, and is derived from the combination of (1) (4) (6) (9):
from the following componentsThe method can be calculated as follows:
further deriving:
from the formulaIt can be seen that if the number of turns, the magnetic path length, the excitation signal and other parameters of the first coil and the second coil are all fixed, the external magnetic field H Outer part The inductance value of the two groups of coils under the action of the external magnetic field or not can be calculated.
The material of the first magnetic core is not limited, and is preferably a soft magnetic material. The soft magnetic material is not limited and comprises cobalt-based amorphous, iron-based nanocrystalline, iron-nickel alloy, iron-cobalt alloy and the like. Preferably, the first magnetic core has high magnetic permeability, so that magnetic field information can be rapidly induced, and the sensitivity of the magnetic sensor is improved.
The material of the second magnetic core is not limited, and is preferably a soft magnetic material. The soft magnetic material is not limited and comprises cobalt-based amorphous, iron-based nanocrystalline, iron-nickel alloy, iron-cobalt alloy and the like. Preferably, the second magnetic core has high magnetic permeability, so that magnetic field information can be rapidly induced, and the sensitivity of the magnetic sensor is improved.
The first magnetic core is not limited in structural form and comprises a strip, a wire, a bar, a block and the like.
The structural form of the second magnetic core is not limited, and the second magnetic core comprises a strip, a wire, a bar, a block and the like.
The shape of the cross section of the first magnetic core perpendicular to the magnetic force lines is not limited, and includes regular shapes such as rectangular, circular, polygonal, etc., and irregular shapes.
The shape of the cross section of the second magnetic core perpendicular to the magnetic force lines is not limited, and includes regular shapes such as rectangular, circular, polygonal, etc., and irregular shapes.
The shape of the cross section of the first magnetic core perpendicular to the magnetic lines of force may be the same as or different from the shape of the cross section of the second magnetic core perpendicular to the magnetic lines of force.
The area of the cross section of the first magnetic core perpendicular to the magnetic flux lines may be the same as or different from the area of the cross section of the second magnetic core perpendicular to the magnetic flux lines.
The first magnetic core and the second magnetic core may or may not be connected together. Preferably, the first magnetic core and the second magnetic core may be integrally formed when they are connected together.
The excitation electrical signal is not limited, and includes an alternating current electrical signal or a pulsed electrical signal, and is a function of time.
As one implementation manner, one end of the first coil and one end of the second coil are respectively connected with the input end of the external circuit, and the other end of the first coil and the other end of the second coil are respectively connected with the output end of the external circuit.
Compared with the prior art, the magnetic sensor has the following beneficial effects:
(1) The magneto-sensitive element has a simple structure and comprises a first magnetic core, a second magnetic core, a first coil and a second coil, wherein the number of turns of the first coil is equal to that of the second coil, the magnetic path length is equal, the winding direction is opposite, the magnetic permeability of the first magnetic core is equal to that of the second magnetic core, the area of each section perpendicular to the magnetic path direction in the first magnetic core is equal, the area of each section perpendicular to the magnetic path direction in the second magnetic core is equal, B-H characteristic curves of the first magnetic core and the second magnetic core in the magnetic field respectively have linear change intervals, and the first magnetic core and the second magnetic core respectively work in the linear intervals during actual measurement;
(2) The sectional area of the first magnetic core is not required to be equal to that of the second magnetic core, so that the requirement on the magnetic core is greatly reduced, the cost is reduced, and different magnetic sensitive elements can be obtained by adjusting different first magnetic cores and different second magnetic cores;
(3) When the magnetic sensor provided by the invention is used, the applied external magnetic field information can be obtained through measuring the inductance values of the two groups of coils, the detection is simple and easy, the detection is convenient, and the detection accuracy can be improved.
Drawings
FIG. 1 is a graph showing the relationship between the magnetic flux of the first coil and the second coil and the exciting current in the magnetic sensor according to the present invention.
FIG. 2 is a graph showing the relationship between the inductance and the exciting current at two ends of the first coil and the second coil in the magneto-sensitive element of the present invention.
FIG. 3 is a graph showing B-H characteristics of a first magnetic core and a second magnetic core of the magnetic sensor of the present invention.
In fig. 4, a is a schematic structural diagram of the magneto-sensitive element in embodiment 1 of the present invention, and b is a schematic sectional structural diagram of the first magnetic core and the second magnetic core.
In fig. 5, a is a schematic structural diagram of the magneto-sensitive element in embodiment 2 of the present invention, and b is a schematic sectional structural diagram of the first magnetic core and the second magnetic core.
In fig. 6, a is a schematic structural diagram of the magneto-sensitive element in embodiment 3 of the present invention, and b is a schematic sectional structural diagram of the first magnetic core and the second magnetic core.
In fig. 7, a is a schematic structural diagram of the magneto-sensitive element in embodiment 4 of the present invention, and b is a schematic sectional structural diagram of the first magnetic core and the second magnetic core.
In fig. 8, a is a schematic cross-sectional structure of the first magnetic core in embodiment 5 of the present invention, and b is a schematic cross-sectional structure of the second magnetic core.
The reference numerals in fig. 4-8 are:
1-a filiform structure; 2-a first magnetic core; 3-a second magnetic core; 4-a first coil; 5-a second coil; 6-input terminal; 7-the other end of the first coil; 8-the other end of the second coil; 9-a first excitation magnetic field; 10-a second excitation magnetic field; 11-an external magnetic field; 12-band structure; 13-a first backbone; 14-profiled strip structure 14; 15-a second backbone; 16-block structure.
Detailed Description
The present invention will be described in further detail with reference to the following examples and drawings, and it should be noted that the examples are intended to facilitate the understanding of the present invention without any limitation thereto.
Example 1:
as shown in fig. 4 (a), the magneto-sensitive element comprises a first magnetic core 2, a first coil 4 wound around the first magnetic core 2, a second magnetic core 3, and a second coil 5 wound around the second magnetic core 3, wherein the winding direction of the first coil 4 is opposite to that of the second coil 5, one end of the first coil 4 and one end of the second coil 5 are respectively connected with an input end 6 of an external circuit, the other end 7 of the first coil 4 and the other end 8 of the second coil 5 are respectively connected with an output end of the external circuit, namely, the external circuit provides exciting current I (t) with the same size and opposite direction for the first coil 4 and the second coil 5 to generate an exciting magnetic field H Excitation 。
The first magnetic core material and the second magnetic core material are the same and are cobalt-based amorphous materials, and have high magnetic permeability and effective magnetic permeability of mu e 。
The first core has a wire-like structure 1 with a diameter D of 100 μm, and each cross section perpendicular to the magnetic path direction in the first core has a circular shape as shown in FIG. 4 (b), and has equal size, i.e., each cross section has equal size S e1 。
The second core has a wire-like structure with a diameter D of 100 μm, and each cross section perpendicular to the magnetic path direction in the second core has a circular shape as shown in FIG. 4 (b), and has equal size, i.e., each cross section has equal size S e2 。
The first coil is an enameled wire with the diameter of 20 mu m, and the enameled wire is directly wound on the surface of the first magnetic core by utilizing a custom winding machine to form the enameled wire. The second coil is an enameled wire with the diameter of 20 mu m, and the enameled wire is directly wound on the surface of the second magnetic core by utilizing a custom winding machine to form the enameled wire.
In this embodiment, each cross-sectional area of the first magnetic core is equal to each cross-sectional area of the first magnetic core, i.e., S e1 ＝S e2 ＝S e The number of turns of the first coil 4 and the second coil 5 are equal, and are both N. The magnetic path length of the first coil is equal to that of the second coil, and the magnetic path lengths are l e 。
In this embodiment, as shown in fig. 4 (a), the first core 2 and the second core 3 are connected in the longitudinal direction as a core of an integral structure.
Under the action of exciting current I (t), the relation between the magnetic flux of the first coil and the exciting current is shown in FIG. 1, and the relation between the inductances at the two ends of the first coil 4 and the exciting current is shown in FIG. 2, namely, under the action of the exciting current, the first coil 4 generates a magnetic field with the magnetic flux of +I s to-I s When the interval changes, the magnetic flux phi is unsaturated and linearly changes, and the two ends of the first coil 4 generate constant inductance value L 1 . The fitted hysteresis loop is shown schematically in FIG. 3 when the first core 2 is in the magnetic field, i.e. the first core has an ideal B-H characteristic in the magnetic field when the excitation current is at +I s to-I s When the interval is changed, the magnetic field strength is +H s to-H s The magnetic induction intensity of the first magnetic core 2 is unsaturated and linearly changed due to interval change, namely the first magnetic core does not reach a magnetization saturation state, +H s to-H s The interval of (2) is called a magnetization linear interval in which a constant inductance value is generated at both ends of the first coil.
Under the action of exciting current I (t), the relationship between the magnetic flux of the second coil 5 and the exciting current is shown in FIG. 1, and the relationship between the inductances at the two ends of the second coil 2 and the exciting current is shown in FIG. 2, namely, under the action of exciting current, the second coil 4 generates a magnetic field with the magnetic flux of +I s to-I s When the interval changes, the magnetic flux phi is unsaturated and linearly changes, and two ends of the second coil generateConstant inductance value L 2 . The second core 3 is in the magnetic field, the fitted hysteresis loop is schematically shown in FIG. 3, i.e. the second core has an ideal B-H characteristic in the magnetic field when the excitation current is at +I s to-I s When the interval is changed, the magnetic field strength is +H s to-H s The magnetic induction intensity of the second magnetic core 3 is unsaturated and linearly changed due to interval change, namely the second magnetic core does not reach the magnetization saturation state, +H s to-H s The interval of (2) is called a magnetization linear interval in which a constant inductance value is generated across the second coil.
When the magnetic sensor is used for measuring an external magnetic field, the method comprises the following steps:
(1) The magneto-sensitive element is placed in an environment without an external magnetic field, exciting current I (t) is introduced into a first coil 4 and a second coil 5 through an input end 6 of an external circuit, the first coil 4 forms a first exciting magnetic field 9, the second coil 5 forms a second exciting magnetic field 10, the directions of the first exciting magnetic field 9 and the second exciting magnetic field 10 are opposite, the magnetic field intensity is equal, and the magnetic fields are all H Excitation guarantee-H S ＜H Excitation ＜+H S I.e. H Excitation The inductance L at two ends of the first coil is measured in the magnetization linear interval of the first magnetic core and the second magnetic core 1 Inductance L at two ends of the second coil 2 At this time L 1 ＝L 2 。
(2) The magneto-sensitive element is placed in an environment in which an external magnetic field 11 is applied, while an excitation current I (t) is supplied to the first coil 4 and the second coil 5 via the input 6 of the external circuit. The first coil 4 forms a first excitation magnetic field 9, the second coil 5 forms a second excitation magnetic field 10, the first excitation magnetic field 9 and the second excitation magnetic field 10 are opposite in direction, the magnetic field strength is equal, and the magnetic fields are H Excitation . The magnetic field strength of the external magnetic field 11 is H Outer part The direction of the external magnetic field 11 is the same as the direction of the excitation magnetic field in the first coil 4, opposite to the direction of the excitation magnetic field in the second coil 5, and ensures-H S ＜H Excitation +H Outer part ＜+H S I.e. H Excitation And H is Outer part The sum is located in the magnetization linear interval of the first magnetic core and the second magnetic core. Measuring first lineInductance L 'across loop 4' 1 Inductance L 'with both ends of the second coil 5' 2 。
(3) External magnetic field H Outer part Can be of the size of L 1 、L 2 、L′ 1 、L′ 2 The preparation method comprises the following steps:
example 2:
in this embodiment, the structure of the magneto-sensitive element is substantially the same as that in embodiment 1, except that:
as shown in fig. 5 (a) and 5 (b), the first magnetic core has an overall shape of a strip-like structure 12 having a thickness of 20 μm and a width D, and each section perpendicular to the magnetic path direction in the first magnetic core has a rectangular shape as shown in fig. 5 (b) and is equal in size; the second magnetic core has an overall shape of a strip-like structure 12 having a thickness of 20 μm and a width D, and each section perpendicular to the magnetic path direction in the second magnetic core has a rectangular shape and an equal size as shown in fig. 5 (b); the strip structure 12 is placed on a custom groove skeleton 13, and the first coil 4 and the second coil 5 are wound on the skeleton 13.
The method for measuring the external magnetic field by using the magneto-sensitive element is the same as that in example 1, the external magnetic field H Outer part Size-passable type(s)Obtained, i.e. by L 1 、L 2 、L′ 1 、L′ 2 Obtained.
Example 3:
in this embodiment, the structure of the magneto-sensitive element is substantially the same as that in embodiment 2, except that:
as shown in fig. 6 (a) and 6 (b), the first core 2 has a strip-like structure with a thickness of 20 μm and a width D1, and each cross section perpendicular to the magnetic path direction in the first core has a rectangular shape as shown in fig. 6 (b) and is equal in size, that isThe cross sections are equal in size and S e1 The method comprises the steps of carrying out a first treatment on the surface of the The second magnetic core 3 has a strip-like structure with a thickness of 20 μm and a width of D2, and each section perpendicular to the magnetic path direction in the second magnetic core has a rectangular shape as shown in FIG. 6 (b), and has equal size, i.e., each section has equal size S e2 The method comprises the steps of carrying out a first treatment on the surface of the And S is e1 ≠S e2 As shown in fig. 6 (a), a strip-shaped magnetic core in which the first magnetic core 2 and the second magnetic core 3 are connected in the longitudinal direction into an integral structure, called a shaped strip structure 14, is placed on the second bobbin 15, and the first coil 4 and the second coil 5 are wound around the second bobbin 15.
When the magnetic sensor is used for measuring an external magnetic field, the method comprises the following steps:
(1) The magneto-sensitive element is placed in an environment without an external magnetic field, exciting current I (t) is introduced into a first coil 4 and a second coil 5 through an input end 6 of an external circuit, the first coil 4 forms a first exciting magnetic field 9, the second coil 5 forms a second exciting magnetic field 10, the directions of the first exciting magnetic field 9 and the second exciting magnetic field 10 are opposite, the magnetic field intensity is equal, and the magnetic fields are all H Excitation guarantee-H S ＜H Excitation ＜+H S I.e. H Excitation The inductance L at two ends of the first coil is measured in the magnetization linear interval of the first magnetic core and the second magnetic core 1 Inductance L at two ends of the second coil 2 。
(2) The magneto-sensitive element is placed in an environment in which an external magnetic field 11 is applied, while an excitation current I (t) is supplied to the first coil 4 and the second coil 5 via the input 6 of the external circuit. The first coil 4 forms a first excitation magnetic field 9, the second coil 5 forms a second excitation magnetic field 10, the first excitation magnetic field 9 and the second excitation magnetic field 10 are opposite in direction, the magnetic field strength is equal, and the magnetic fields are H Excitation wherein-H S ＜H Excitation ＜+H S I.e. H Excitation Is located in the magnetization linear interval of the first magnetic core and the second magnetic core. The magnitude of the magnetic field strength of the external magnetic field 11 is H Outer part The direction of the external magnetic field 11 is the same as the direction of the excitation magnetic field in the first coil 4 and opposite to the direction of the excitation magnetic field in the second coil 5. And, guarantee-H S ＜H Excitation +H Outer part ＜+H S I.e. H Excitation And H is Outer part The sum is located in the magnetization linear interval of the first magnetic core and the second magnetic core. Measuring inductance L 'across first coil 4' 1 Inductance L 'with both ends of the second coil 5' 2 。
(3) External magnetic field H Outer part Can be of the size of L 1 、L 2 、L′ 1 、L′ 2 The preparation method comprises the following steps:
example 4:
in this embodiment, the structure of the magneto-sensitive element is substantially the same as that in embodiment 3, except that: as shown in fig. 7 (a) and 7 (b), the bulk structure 16 of the first magnetic core having the overall shape of thickness h and width D1 is formed by laminating and curing the strip-like structure of embodiment 3 having the thickness of 20 μm and the width D1; the second core has a bulk structure of thickness h and width D2, and is formed by laminating and curing the strip-like structure of embodiment 3 of thickness 20 μm and width D2. As shown in fig. 7 (a), the block-shaped magnetic core in which the first magnetic core 2 and the second magnetic core 3 are connected in the longitudinal direction to form an integral structure is called a shaped block structure 16.
The method for measuring the external magnetic field by using the magneto-sensitive element is the same as that in example 3, the external magnetic field H Outer part Size-passable type(s)Obtained, i.e. by L 1 、L 2 、L′ 1 、L′ 2 Obtained.
Example 5:
in this embodiment, the structure of the magneto-sensitive element is substantially the same as that in embodiment 4, except that: the first magnetic core has a block-like overall shape, and each cross section perpendicular to the magnetic path direction in the first magnetic core has an irregular shape as shown in fig. 8 (a), and has equal size, i.e., each cross section has equal size and is S e1 The method comprises the steps of carrying out a first treatment on the surface of the The second magnetic core has a block-like overall shape, and each cross section perpendicular to the magnetic path direction in the second magnetic core has an irregular shape as shown in fig. 8 (b), and has equal size, i.e., each cross section has equal size and is S e2 。
The method for measuring the external magnetic field by using the magneto-sensitive element is the same as that in example 3, the external magnetic field H Outer part Size-passable type(s)Obtained, i.e. by L 1 、L 2 、L′ 1 、L′ 2 Obtained.
While the foregoing embodiments have been described in detail in connection with the embodiments of the invention, it should be understood that the foregoing embodiments are merely illustrative of the invention and are not intended to limit the invention, and any modifications, additions, substitutions and the like made within the principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A magneto-sensitive element, characterized by: the magnetic core comprises a first magnetic core, a first coil and a second magnetic core which are wound around the periphery of the first magnetic core, and a second coil which is wound around the periphery of the second magnetic core, wherein the winding direction of the first coil is opposite to the winding direction of the second coil; the external circuit is respectively connected with two ends of the first coil and two ends of the second coil and is used for providing exciting currents I (t) with the same size and opposite directions for the first coil and the second coil to generate an exciting magnetic field;
under the action of exciting current I (t), the first coil generates magnetic field when exciting current is +I s to-I s When the interval is changed, the magnetic field strength is +H s to-H s The magnetic induction intensity of the first magnetic core is unsaturated and linearly changed due to interval change, namely the first magnetic core does not reach a magnetization saturation state, +H s to-H s Is called a magnetization linear section in which a constant inductance value is generated at both ends of the first coil;
under the action of exciting current I (t), the second coil generates magnetic fieldWhen the exciting current is +I s to-I s When the interval is changed, the magnetic field strength is +H s to-H s The magnetic induction intensity of the second magnetic core is unsaturated and linearly changed due to interval change, namely the second magnetic core does not reach a magnetization saturation state, +H s to-H s The interval of (2) is called a magnetization linear interval, and a constant inductance value is generated at two ends of the second coil in the magnetization linear interval;
the number of turns of the first coil is equal to the number of turns of the second coil, and the turns of the first coil and the turns of the second coil are N;
the magnetic permeability of the first magnetic core is equal to that of the second magnetic core and is mu e ；
The first magnetic core has uniform overall shape, i.e. the areas of the sections perpendicular to the magnetic path direction in the first magnetic core are equal and S e1 ；
The second magnetic core has uniform overall shape, i.e. the areas of the sections perpendicular to the magnetic path direction in the second magnetic core are equal and S e2 ；
The magnetic path length of the first coil is equal to that of the second coil, and the magnetic path lengths are l e 。
2. A magneto-sensitive element according to claim 1, wherein: the first magnetic core is made of soft magnetic materials, and the second magnetic core is made of soft magnetic materials;
preferably, the soft magnetic material comprises one or more of cobalt-based amorphous, iron-based nanocrystalline, iron-nickel alloy and iron-cobalt alloy.
3. A magneto-sensitive element according to claim 1, wherein: the material structure of the first magnetic core comprises a strip, a wire, a bar and a block;
preferably, the material structure of the second magnetic core includes a strip, a wire, a bar, and a block.
4. A magneto-sensitive element according to claim 1, wherein: the cross section of the first magnetic core perpendicular to the magnetic force lines is in a regular shape or an irregular shape;
preferably, the regular shape includes a rectangle, a circle, and a polygon.
Preferably, the cross section of the second magnetic core perpendicular to the magnetic force lines is in a regular shape or in an irregular shape;
preferably, the regular shape includes a rectangle, a circle, and a polygon.
5. A magneto-sensitive element according to claim 1, wherein: the shape of the cross section of the first magnetic core perpendicular to the magnetic lines of force is the same as or different from the shape of the cross section of the second magnetic core perpendicular to the magnetic lines of force.
6. A magneto-sensitive element according to claim 1, wherein: the first magnetic core and the second magnetic core are connected together or not connected together;
preferably, the first magnetic core and the second magnetic core are integrally formed.
7. A magneto-sensitive element according to claim 1, wherein: one end of the first coil and one end of the second coil are respectively connected with the input end of the external circuit, and the other end of the first coil and the other end of the second coil are respectively connected with the output end of the external circuit.
8. A method of measuring an external magnetic field using a magneto-sensitive element according to any one of claims 1 to 7, characterized by:
firstly, the magneto-sensitive element is placed in an environment without an external magnetic field, and an external circuit provides exciting currents I (t) with the same size and opposite directions for a first coil and a second coil to generate an exciting magnetic field H Excitation Ensure H Excitation Is positioned in the magnetization linear section and measures the inductance L at the two ends of the first coil 1 Inductance L at two ends of the second coil 2 ；
Then, the magneto-sensitive element is placed in an external magnetic field H Outer part Simultaneously supplying exciting currents I (t) with the same magnitude and opposite directions to the first coil and the second coil through an external circuit to generate an exciting magnetic field H Excitation Ensure H Excitation +H Outer part Is positioned in the magnetization linear section, and the inductance L 'at the two ends of the first coil is measured' 1 Inductance L 'with both ends of the second coil' 2 ；
External magnetic field H Outer part Can be of the size of L 1 、L 2 、L′ 1 、L′ 2 The method comprises the following specific steps:
9. the method as set forth in claim 8, wherein: when the cross section area S of the first magnetic core e1 Cross-sectional area S with the second magnetic core e2 When the phases are equal to each other,
10. a magnetic sensor, characterized by: comprising a magneto-sensitive element according to any one of claims 1 to 7.
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