A magnetic sensor, a method for measuring an external magnetic field using the same, and a magnetic sensor

Abstract

This invention provides a magnetic sensitive element, a method for measuring an external magnetic field using the same, and a magnetic sensor. The magnetic sensitive element includes first and second magnetic cores, and first and second coils. The first and second coils have equal numbers of turns, equal magnetic circuit lengths, and opposite winding directions. The first and second magnetic cores have equal permeability, and the cross-sectional areas of each section perpendicular to the magnetic circuit direction in the first and second magnetic cores are equal. Under the action of an excitation current I(t) of the same magnitude but opposite direction, the first and second coils generate a magnetic field. When the excitation current is +I... s to‑I s When the magnetic field strength varies within the range of +H, s To -H s The B-H characteristic curves of the first and second magnetic cores exhibit linear variation within a given range. This component has a simple structure, reducing the requirements for the magnetic cores and lowering costs. In actual measurements, the first and second magnetic cores operate within this linear range. By measuring the inductance values ​​of the two sets of coils, the applied external magnetic field information can be obtained. This method is simple and easy to implement, and it improves detection accuracy.

Description

Technical Field

[0001] This invention belongs to the field of magnetic sensing technology, specifically relating to a magnetic sensitive element, a method for measuring an external magnetic field using it, and a magnetic sensor. Background Technology

[0002] A magnetic sensor is a functional device that senses changes in magnetic signals. The technical principles of magnetic sensors include the Hall effect, fluxgate principle, Wiegand effect, giant magnetoresistance effect, and tunneling magnetoresistance effect.

[0003] Magnetic sensing elements are crucial components for sensing and measuring magnetic fields in magnetic sensing. Inductors, formed by winding a magnetic core, are a commonly used type of magnetic sensing element. Magnetic field information is obtained by measuring the inductance. However, because the inductance value is closely related to the material, structure, shape, and size of the magnetic core, even small changes in these factors can alter the core's ability to sense magnetic fields. Therefore, practical applications place stringent requirements on magnetic cores, often demanding consistent core structure, shape, and dimensions, significantly increasing the difficulty and cost of core manufacturing. Summary of the Invention

[0004] In view of the above-mentioned technical status, the present invention provides a magnetic sensitive element including a magnetic core and a coil, which can reduce the requirements for the structure, shape and size of the magnetic core, thereby greatly reducing the manufacturing difficulty and cost of the magnetic core, and the method of measuring the external magnetic field using it is simple and easy.

[0005] The technical solution provided by this invention is: a magnetic sensitive element, comprising a first magnetic core, a first coil wound around the periphery of the first magnetic core, a second magnetic core, and a second coil wound around the periphery of the second magnetic core, wherein the winding direction of the first coil is opposite to that of the second coil; an external circuit is connected to both ends of the first coil and both ends of the second coil, respectively, for providing excitation currents I(t) of the same magnitude but opposite directions to the first coil and the second coil, thereby generating an excitation magnetic field H. 激励 ;

[0006] Under the action of the excitation current I(t), the first coil generates a magnetic field, and the relationship between its magnetic flux and the excitation current is as follows: Figure 1 As shown, the relationship between the inductance across the first coil and the excitation current is as follows: Figure 2 As shown, the excitation current is at +I s to-I s When the magnetic flux Φ changes within the interval, it is unsaturated and changes linearly, resulting in a constant inductance value L1 across the first coil. When the first magnetic core is located in this magnetic field, the schematic diagram of the fitted hysteresis loop is shown below. Figure 3 As shown, the first magnetic core has an ideal BH characteristic curve in this magnetic field, when the excitation current is +I s to-I s When the magnetic field strength varies within the range of +H, s To-Hs The magnetic flux density of the first magnetic core changes linearly within a certain range, indicating that the first magnetic core has not reached magnetization saturation. s To-H s The interval is called the magnetization linear interval, and a constant inductance value is generated at both ends of the first coil in this magnetization linear interval;

[0007] Under the action of the excitation current I(t), the second coil generates a magnetic field, and the relationship between its magnetic flux and the excitation current is as follows: Figure 1 As shown, the relationship between the inductance across the second coil and the excitation current is as follows: Figure 2 As shown, the excitation current is at +I s to-I s When the magnetic flux Φ changes within the interval, it is unsaturated and changes linearly, resulting in a constant inductance value L2 across the second coil. When the second magnetic core is located in this magnetic field, the schematic diagram of the fitted hysteresis loop is shown below. Figure 3 As shown, the second magnetic core exhibits an ideal BH characteristic curve in this magnetic field, when the excitation current is +I s to-I s When the magnetic field strength varies within the range of +H, s To-H s The magnetic flux density of the second magnetic core changes linearly within the range, indicating that the second magnetic core has not reached magnetization saturation. s To-H s The interval is called the magnetization linear interval, and a constant inductance value is generated at both ends of the second coil within this magnetization linear interval;

[0008] The number of turns in the first coil is the same as the number of turns in the second coil, both being N;

[0009] The permeability of the first magnetic core is the same as that of the second magnetic core, both being μ. e ;

[0010] The first magnetic core has a uniform overall shape, meaning that the area (called the effective cross-sectional area) of each cross-section perpendicular to the magnetic circuit direction in the first magnetic core is equal, all being S. e1 ;

[0011] The second magnetic core has a uniform overall shape; that is, the area (called the effective cross-sectional area) of each cross-section perpendicular to the magnetic circuit direction in the second magnetic core is equal, all being S. e2 ;

[0012] The magnetic path length of the first coil is equal to that of the second coil, both being l. e .

[0013] The magnetic sensing element of the present invention can obtain information about an external magnetic field, including the following steps:

[0014] First, the magnetic sensitive element of the present invention is placed in an environment without an external magnetic field. Under the condition that the first coil and the second coil are provided with excitation currents I(t) of the same magnitude but opposite direction through an external circuit, an excitation magnetic field H is generated. 激励 , ensure H 激励 Located within the magnetization linear region, the inductance L1 at both ends of the first coil and the inductance L2 at both ends of the second coil are measured;

[0015] Then, the magnetic sensing element of the present invention is placed under an applied external magnetic field H. 外 In this environment, an excitation current I(t) of the same magnitude but opposite direction is simultaneously supplied to the first and second coils via an external circuit, generating an excitation magnetic field H. 激励 , ensure H 激励 +H 外 Located within the magnetization linear region, the inductance L′1 at the ends of the first coil and the inductance L′2 at the ends of the second coil are measured;

[0016] Then the external magnetic field H 外 The size can be obtained through L1, L2, L′1, and L′2, specifically:

[0017]

[0018] When the cross-sectional area S of the first magnetic core e1 The cross-sectional area S of the second magnetic core e2 When they are equal,

[0019]

[0020] Specifically as follows:

[0021] In this invention, formulas ① to ① are used. The symbols in the text are as follows:

[0022] I(t) represents the excitation current, which is a function of time;

[0023] N represents the number of turns in the first coil, which is the same as the number of turns in the second coil;

[0024] l e This represents the magnetic circuit length of the first magnetic core, which is also the magnetic circuit length of the second magnetic core.

[0025] μ e The permeability of the first magnetic core is the same as the permeability of the second magnetic core.

[0026] H 激励 This represents the magnetic field strength generated when the excitation current acts on the coil;

[0027] H 外 This represents the strength of the applied external magnetic field;

[0028] B represents the magnetic flux density;

[0029] Φ represents magnetic flux;

[0030] L represents the inductance value across the coil under the action of the excitation current. The inductance value of the first coil is denoted as L1, and the inductance value of the second coil is denoted as L2.

[0031] L' represents the excitation current and external magnetic field H. 外 The inductance values ​​at both ends of the coils are simultaneously affected. The inductance value of the first coil is denoted as L′1, and the inductance value of the second coil is denoted as L′2.

[0032] (a) The cross-sectional area S of the first magnetic core e1 The cross-sectional area S of the second magnetic core e2 Equal, i.e., S e1 =S e2 =S e hour

[0033] (1) The excitation current I(t) acts on the first coil and the second coil respectively, and there is no external magnetic field H. 外 When applied to the first and second coils:

[0034] N·I(t)=H 激励 ·l e ①

[0035] B = μ e ·H 激励 ②

[0036] From ① and ②, we can obtain:

[0037]

[0038] And Φ=N·B·S e ④

[0039] From ③ and ④, we can obtain:

[0040]

[0041] And Φ=L·I⑥

[0042] From ⑤ and ⑥, we can obtain:

[0043]

[0044] The inductance values ​​of the first and second coils can then be derived:

[0045]

[0046] (2) The excitation current I(t) acts on the first coil and the second coil respectively, and the external magnetic field H 外When applied to the first coil and the second coil

[0047] The first magnetic core is subjected to excitation current I(t) and external magnetic field H. 外 Under the combined effect of these factors, it still operates within the magnetization linear range, therefore the permeability remains unchanged;

[0048] The second magnetic core is subjected to excitation current I(t) and external magnetic field H. 外 Under the combined effect of these factors, it still operates within the magnetization linear range, therefore the permeability remains unchanged;

[0049] Since the first coil and the second coil rotate in opposite directions, under the external magnetic field H 外 Under the influence of the first and second coils, the direction of the excitation magnetic field of the first group of coils is the same as the direction of the external magnetic field, which increases the magnetic flux in the core. The direction of the excitation magnetic field of the other group of coils is opposite to the direction of the external magnetic field, which decreases the magnetic flux in the core. Assuming that the direction of the excitation magnetic field in the first coil is the same as the direction of the external magnetic field, and the direction of the excitation magnetic field in the second coil is opposite to the direction of the external magnetic field, ② can be transformed into ⑨ or ⑩ as follows.

[0050] B = μ e ·(H 激励 +H 外 ) ⑨

[0051] B = μ e ·(H 激励 -H 外 ) ⑩

[0052] The inductance values ​​of the first and second coils under the influence of an external magnetic field are derived from ①④⑥:

[0053]

[0054]

[0055] Depend on and It can be calculated that:

[0056]

[0057] Substitute ⑧ into It can be concluded that:

[0058]

[0059] From the formula It can be seen that if the number of turns, magnetic circuit length, cross-sectional area, and input signal of the first and second coils are all fixed, the external magnetic field H 外 The inductance can be calculated from the inductance values ​​of the two sets of coils under the influence of an external magnetic field.

[0060] (II) Effective cross-sectional area S of the first magnetic core e1 With the effective cross-sectional area S of the second magnetic core e2 Unequal S e S e1 ≠S e2 hour

[0061] (1) The excitation current I(t) acts on the first coil and the second coil respectively, and there is no external magnetic field H. 外 When applied to the first coil and the second coil

[0062] The following conclusions can be drawn from the combined derivation of ①②④⑥:

[0063]

[0064]

[0065] (2) The excitation current I(t) acts on the first coil and the second coil respectively, and the external magnetic field H 外 When applied to the first coil and the second coil

[0066] The first magnetic core is subjected to excitation current I(t) and external magnetic field H. 外 Under the combined effect of these factors, it still operates within the magnetization linear range, therefore the permeability remains unchanged;

[0067] The second magnetic core is subjected to alternating current I(t) and external magnetic field H. 外 Under the combined effect of these factors, it still operates within the magnetization linear range, therefore the permeability remains unchanged;

[0068] Since the first coil and the second coil rotate in opposite directions, under the external magnetic field H 外 Under the influence of the external magnetic field, the excitation magnetic field of one set of coils in the first and second coils is in the same direction as the external magnetic field, increasing the magnetic flux in the core. The excitation magnetic field of the other set of coils is in the opposite direction to the external magnetic field, decreasing the magnetic flux in the core. Assuming that the excitation magnetic field in the first coil is in the same direction as the external magnetic field, and the excitation magnetic field in the second coil is in the opposite direction to the external magnetic field, we can deduce the following from ①④⑥⑨⑩:

[0069]

[0070]

[0071] Depend on It can be calculated that:

[0072]

[0073] Further derivation yields:

[0074]

[0075] From the formula It can be seen that if the number of turns, magnetic circuit length, and excitation signal of the first and second coils are all fixed, the external magnetic field H 外 The inductance can be calculated from the inductance values ​​of the two sets of coils under the influence of an external magnetic field.

[0076] The material of the first magnetic core is not limited, but is preferably a soft magnetic material. The soft magnetic material is not limited, and includes cobalt-based amorphous materials, iron-based amorphous materials, iron-based nanocrystalline materials, iron-nickel alloys, iron-cobalt alloys, etc. Preferably, the first magnetic core has high permeability, which allows it to quickly sense magnetic field information, thereby improving the sensitivity of the magnetic sensing element.

[0077] The material of the second magnetic core is not limited, but is preferably a soft magnetic material. The soft magnetic material is not limited, and includes cobalt-based amorphous materials, iron-based amorphous materials, iron-based nanocrystalline materials, iron-nickel alloys, iron-cobalt alloys, etc. Preferably, the second magnetic core has high permeability, which allows it to quickly sense magnetic field information, thereby improving the sensitivity of the magnetic sensing element.

[0078] The structure of the first magnetic core is not limited, including strips, wires, rods, and blocks.

[0079] The structure of the second magnetic core is not limited, including strips, wires, rods, and blocks.

[0080] The shape of the cross section of the first magnetic core perpendicular to the magnetic field lines is not limited, including regular shapes such as rectangles, circles, and polygons, as well as irregular shapes.

[0081] The shape of the cross section of the second magnetic core perpendicular to the magnetic field lines is not limited, including regular shapes such as rectangles, circles, and polygons, as well as irregular shapes.

[0082] The shape of the cross section perpendicular to the magnetic field lines of the first magnetic core can be the same as or different from the shape of the cross section perpendicular to the magnetic field lines of the second magnetic core.

[0083] The area of ​​the cross-section perpendicular to the magnetic field lines of the first magnetic core can be the same as or different from the area of ​​the cross-section perpendicular to the magnetic field lines of the second magnetic core.

[0084] The first magnetic core and the second magnetic core may or may not be connected together. Preferably, when the first magnetic core and the second magnetic core are connected together, they can be integrally formed.

[0085] The excitation electrical signal is not limited and includes alternating current signals or pulse signals, both of which are functions of time.

[0086] In one implementation, one end of the first coil and one end of the second coil are respectively connected to the input terminal of the external circuit, and the other end of the first coil and the other end of the second coil are respectively connected to the output terminal of the external circuit.

[0087] Compared with the prior art, the magnetic sensitive element of the present invention has the following beneficial effects:

[0088] (1) The magnetic sensitive element has a simple structure, including a first magnetic core, a second magnetic core, a first coil and a second coil. It is only necessary to set the number of turns of the first coil and the second coil to be equal, the magnetic circuit length to be equal and the winding direction to be opposite. The permeability of the first magnetic core and the second magnetic core is equal. The area of ​​each cross section of the first magnetic core perpendicular to the magnetic circuit direction is equal. The area of ​​each cross section of the second magnetic core perpendicular to the magnetic circuit direction is equal. In the magnetic field, the BH characteristic curves of the first magnetic core and the second magnetic core have linear change ranges respectively. In actual measurement, the first magnetic core and the second magnetic core work in the linear range respectively.

[0089] (2) It is not necessary for the cross-sectional area of ​​the first magnetic core to be equal to that of the second magnetic core. On the one hand, this greatly reduces the requirements for the magnetic core and reduces the cost. On the other hand, different magnetic sensitive elements can be obtained by adjusting different first and second magnetic cores.

[0090] (3) When using the magnetic sensitive element of the present invention, the information of the applied external magnetic field can be obtained by measuring the inductance values ​​of the two sets of coils. It is simple, easy to perform, convenient to detect, and can improve the detection accuracy. Attached Figure Description

[0091] Figure 1 This is a curve showing the relationship between the magnetic flux of the first coil and the excitation current in the magnetic sensitive element of this invention.

[0092] Figure 2 This is a curve showing the relationship between the inductance at both ends of the first and second coils and the excitation current in the magnetic sensitive element of this invention.

[0093] Figure 3 These are the BH characteristic curves of the first and second magnetic cores in the magnetic sensitive element of this invention.

[0094] Figure 4 Figure a is a schematic diagram of the magnetic sensitive element structure in Embodiment 1 of the present invention, and Figure b is a schematic diagram of the cross-sectional structure of the first magnetic core and the second magnetic core.

[0095] Figure 5 Figure a is a schematic diagram of the magnetic sensitive element structure in Embodiment 2 of the present invention, and Figure b is a schematic diagram of the cross-sectional structure of the first magnetic core and the second magnetic core.

[0096] Figure 6 Figure a is a schematic diagram of the magnetic sensitive element structure in Embodiment 3 of the present invention, and Figure b is a schematic diagram of the cross-sectional structure of the first magnetic core and the second magnetic core.

[0097] Figure 7 Figure a is a schematic diagram of the magnetic sensitive element structure in Embodiment 4 of the present invention, and Figure b is a schematic diagram of the cross-sectional structure of the first magnetic core and the second magnetic core.

[0098] Figure 8 In the figure, Figure a is a schematic diagram of the cross-sectional structure of the first magnetic core in Embodiment 5 of the present invention, and Figure b is a schematic diagram of the cross-sectional structure of the second magnetic core.

[0099] Figure 4-8 The attached figures are labeled as follows:

[0100] 1-Filament structure; 2-First magnetic core; 3-Second magnetic core; 4-First coil; 5-Second coil; 6-Input end; 7-Other end of the first coil; 8-Other end of the second coil; 9-First excitation magnetic field; 10-Second excitation magnetic field; 11-External magnetic field; 12-Strip structure; 13-First skeleton; 14-Irregular strip structure; 15-Second skeleton; 16-Block structure. Detailed Implementation

[0101] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention and do not limit it in any way.

[0102] Example 1:

[0103] like Figure 4 As shown in Figure (a), the magnetic sensitive element includes 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. 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 to the input terminal 6 of the external circuit, and the other end 7 of the first coil 4 and the other end 8 of the second coil 5 are respectively connected to the output terminal of the external circuit. That is, the external circuit provides the first coil 4 and the second coil 5 with excitation currents I(t) of the same magnitude but opposite directions, generating an excitation magnetic field H. 激励 .

[0104] The first magnetic core material is the same as the second magnetic core material; both are cobalt-based amorphous materials with high permeability, and the effective permeability is μ in both cases. e .

[0105] The first magnetic core has an overall shape of a filamentary structure with a diameter D of 100 μm. The shapes of the cross-sections of the first magnetic core perpendicular to the magnetic circuit direction are as follows: Figure 4 As shown in Figure (b), all are circles and are of equal size, meaning that the cross-sectional areas are all equal in size, S. e1 .

[0106] The second magnetic core has an overall shape of a filamentary structure with a diameter D of 100 μm. The shapes of the cross-sections of the second magnetic core perpendicular to the magnetic circuit direction are as follows: Figure 4 As shown in Figure (b), all are circles and are of equal size, meaning that the cross-sectional areas are all equal in size, S. e2 .

[0107] The first coil is made of 20μm diameter enameled wire, which is formed by directly winding the enameled wire onto the surface of the first magnetic core using a custom-made winding machine. The second coil is also made of 20μm diameter enameled wire, which is formed by directly winding the enameled wire onto the surface of the second magnetic core using a custom-made winding machine.

[0108] In this embodiment, the cross-sectional areas of the first magnetic core are equal to the cross-sectional areas of the first magnetic core, i.e., S e1 =S e2 =S e The number of turns in the first coil (coil 4) and the second coil (coil 5) are equal, both being N. The magnetic path length of the first coil is equal to the magnetic path length of the second coil, both being l. e .

[0109] In this embodiment, as Figure 4 As shown in Figure (a), the first magnetic core 2 and the second magnetic core 3 are connected in the length direction to form an integral structure.

[0110] Under the action of the excitation current I(t), the relationship between the magnetic flux of the first coil and the excitation current is as follows: Figure 1 As shown, the relationship between the inductance across the first coil 4 and the excitation current is as follows: Figure 2 As shown, under the action of the excitation current, the first coil 4 generates a magnetic field, and its magnetic flux is at +I s to-I s When the magnetic flux Φ changes within the interval, it is unsaturated and changes linearly, resulting in a constant inductance value L1 across the first coil 4. When the first magnetic core 2 is located in this magnetic field, the schematic diagram of the fitted hysteresis loop is shown below. Figure 3 As shown, the first magnetic core has an ideal BH characteristic curve in the magnetic field, when the excitation current is +I s to-I s When the magnetic field strength varies within the range of +H, s To-H s The magnetic flux density of the first magnetic core 2 varies linearly within a certain range, indicating that the first magnetic core has not reached magnetization saturation. s To-H s The interval is called the magnetization linear interval, and a constant inductance value is generated at both ends of the first coil within this magnetization linear interval.

[0111] Under the action of the excitation current I(t), the relationship between the magnetic flux of the second coil 5 and the excitation current is as follows: Figure 1As shown, the relationship between the inductance across the second coil 2 and the excitation current is as follows: Figure 2 As shown, under the action of the excitation current, the second coil 4 generates a magnetic field, and its magnetic flux is at +I s to-I s When the magnetic flux Φ changes within the interval, it is unsaturated and changes linearly, resulting in a constant inductance value L2 across the second coil. When the second magnetic core 3 is located in this magnetic field, the schematic diagram of the fitted hysteresis loop is shown below. Figure 3 As shown, the second magnetic core exhibits an ideal BH characteristic curve in the magnetic field, when the excitation current is +I s to-I s When the magnetic field strength varies within the range of +H, s To-H s The magnetic flux density of the second magnetic core 3 changes linearly within a certain range, indicating that the second magnetic core has not reached magnetization saturation. s To-H s The interval is called the magnetization linear interval, and a constant inductance value is generated at both ends of the second coil within this magnetization linear interval.

[0112] The steps for measuring an external magnetic field using this magnetic sensing element are as follows:

[0113] (1) Place the magnetic sensitive element in an environment without an external magnetic field, and pass an excitation current I(t) to the first coil 4 and the second coil 5 through the input terminal 6 of the external circuit. The first coil 4 forms a first excitation magnetic field 9, and 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 and have equal magnetic field strength, both being H. 激励 , guarantee H S <H 激励 <+H S H 激励 Located in the magnetization linear region between the first and second magnetic cores, the inductance L1 at the ends of the first coil and the inductance L2 at the ends of the second coil are measured, where L1 = L2.

[0114] (2) The magnetic sensitive element is placed in an environment where an external magnetic field 11 is applied, and an excitation current I(t) is simultaneously supplied to the first coil 4 and the second coil 5 through the input terminal 6 of the external circuit. The first coil 4 forms a first excitation magnetic field 9, and 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 in opposite directions and have equal magnitudes, both being H. 激励 The magnitude of the magnetic field strength of external magnetic field 11 is H. 外 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 ensures that -H S <H 激励 +H 外 <+H SH 激励 With H 外 The sum lies within the magnetization linearity range of the first and second magnetic cores. Measure the inductance L′1 across the first coil 4 and the inductance L′2 across the second coil 5.

[0115] (3) External magnetic field H 外 The size can be obtained through L1, L2, L′1, and L′2, specifically:

[0116]

[0117] Example 2:

[0118] In this embodiment, the structure of the magnetic sensitive element is basically the same as that in Embodiment 1, except that:

[0119] like Figure 5 As shown in Figure (a) and Figure (b) of 5, the first magnetic core has an overall shape of a strip-shaped structure 12 with a thickness of 20 μm and a width of D. The shapes of each cross-section of the first magnetic core perpendicular to the magnetic circuit direction are as follows. Figure 5 As shown in Figure (b), all are rectangular and of equal size; the second magnetic core has an overall shape of a strip-like structure 12 with a thickness of 20 μm and a width of D. The shapes of each cross-section of the second magnetic core perpendicular to the magnetic circuit direction are as follows. Figure 5 As shown in Figure (b), all are rectangles and of equal size; the strip structure 12 is placed on a custom-made grooved frame 13, and the first coil 4 and the second coil 5 are wound on the frame 13.

[0120] The method for measuring the external magnetic field using this magnetic sensing element is the same as that in Example 1, where the external magnetic field H... 外 The size can be expressed by formula It can be obtained, that is, it can be obtained through L1, L2, L′1, L′2.

[0121] Example 3:

[0122] In this embodiment, the structure of the magnetic sensitive element is basically the same as that in Embodiment 2, except that:

[0123] like Figure 6 As shown in Figure (a) and Figure (b) of 6, the first magnetic core 2 has an overall strip-like structure with a thickness of 20 μm and a width of D1. The shapes of the cross-sections of the first magnetic core perpendicular to the magnetic circuit direction are as follows. Figure 6 As shown in Figure (b), all are rectangles and are all the same size, that is, all have the same cross-sectional area, S. e1 The second magnetic core 3 has an overall shape of a strip-like structure with a thickness of 20 μm and a width of D2. The shapes of the cross-sections of the second magnetic core perpendicular to the magnetic circuit direction are as follows: Figure 6As shown in Figure (b), all are rectangles and are all the same size, that is, all have the same cross-sectional area, S. e2 And S e1 ≠S e2 ,like Figure 6 As shown in (a), the first magnetic core 2 and the second magnetic core 3 are connected in the length direction to form a strip-shaped magnetic core, which is called the irregular strip structure 14. It is placed on the second frame 15, and the first coil 4 and the second coil 5 are wound on the second frame 15.

[0124] The steps for measuring an external magnetic field using this magnetic sensing element are as follows:

[0125] (1) Place the magnetic sensitive element in an environment without an external magnetic field, and pass an excitation current I(t) to the first coil 4 and the second coil 5 through the input terminal 6 of the external circuit. The first coil 4 forms a first excitation magnetic field 9, and 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 and have equal magnetic field strength, both being H. 激励 , guarantee H S <H 激励 <+H S H 激励 Located in the magnetization linear region between the first and second magnetic cores, the inductance L1 at both ends of the first coil and the inductance L2 at both ends of the second coil are measured.

[0126] (2) The magnetic sensitive element is placed in an environment where an external magnetic field 11 is applied, and an excitation current I(t) is simultaneously supplied to the first coil 4 and the second coil 5 through the input terminal 6 of the external circuit. The first coil 4 forms a first excitation magnetic field 9, and 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 in opposite directions and have equal magnitudes, both being H. 激励 , where —H S <H 激励 <+H S H 激励 It is located within the magnetization linear region between the first and second magnetic cores. The magnitude of the magnetic field strength of the external magnetic field 11 is H. 外 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. Furthermore, it is ensured that —H S <H 激励 +H 外 <+H S H 激励 With H 外 The sum lies within the magnetization linearity range of the first and second magnetic cores. Measure the inductance L′1 across the first coil 4 and the inductance L′2 across the second coil 5.

[0127] (3) External magnetic field H 外The size can be obtained through L1, L2, L′1, and L′2, specifically:

[0128]

[0129] Example 4:

[0130] In this embodiment, the structure of the magnetic sensitive element is basically the same as that in Embodiment 3, except that: as shown in the following... Figure 7 As shown in Figure (a) and Figure (b) of 7, the first magnetic core has an overall block structure 16 with a thickness of h and a width of D1, which is formed by stacking and solidifying the strip-shaped structure with a thickness of 20 μm and a width of D1 in Example 3; the second magnetic core has an overall block structure with a thickness of h and a width of D2, which is formed by stacking and solidifying the strip-shaped structure with a thickness of 20 μm and a width of D2 in Example 3. Figure 7 As shown in Figure (a), the first magnetic core 2 and the second magnetic core 3 are connected in the length direction to form a block-shaped magnetic core, which is called the irregular block structure 16.

[0131] The method for measuring the external magnetic field using this magnetic sensing element is the same as that in Example 3, where the external magnetic field H 外 The size can be expressed by formula It can be obtained, that is, it can be obtained through L1, L2, L′1, L′2.

[0132] Example 5:

[0133] In this embodiment, the structure of the magnetic sensing element is basically the same as that in Embodiment 4, except that: the overall shape of the first magnetic core is a block structure, and the shape of each cross-section of the first magnetic core perpendicular to the magnetic circuit direction is as follows. Figure 8 As shown in Figure (a), the shape is irregular and all parts are of equal size, meaning that all cross-sectional areas are equal in size, S. e1 The second magnetic core has a block-like structure, and the shapes of each cross-section perpendicular to the magnetic circuit direction are as follows: Figure 8 As shown in Figure (b), the shape is irregular and all parts are of equal size, meaning that all cross-sectional areas are equal in size, S. e2 .

[0134] The method for measuring the external magnetic field using this magnetic sensing element is the same as that in Example 3, where the external magnetic field H 外 The size can be expressed by formula It can be obtained, that is, it can be obtained through L1, L2, L′1, L′2.

[0135] The embodiments described above provide a detailed explanation of the technical solution of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for measuring an external magnetic field using a magnetic sensor element, characterized by: The magnetic sensitive element comprises a first magnetic core, a first coil wound around the periphery of the first magnetic core, a second magnetic core, and a second coil wound around the periphery of the second magnetic core, the winding direction of the first coil being opposite to the winding direction of the second coil; an external circuit is connected to the two ends of the first coil and the two ends of the second coil respectively, for providing the first coil and the second coil with exciting currents of the same size and opposite directions , to generate an exciting magnetic field; Under the action of excitation current , the first coil generates a magnetic field, when the excitation current changes in the interval +I s to I s , the magnetic field strength changes in the interval H s to H s , the magnetic induction intensity of the first magnetic core is not saturated and changes linearly, that is, the first magnetic core does not reach the magnetization saturation state, and the interval H s to H s is called the magnetization linear interval, and a constant inductance value is generated at both ends of the first coil in the magnetization linear interval; Under the action of excitation current , the second coil generates a magnetic field, when the excitation current changes in the interval of I s to I s , the magnetic field strength changes in the interval of H s to H s , the magnetic induction intensity of the second magnetic core is not saturated and changes linearly, that is, the second magnetic core does not reach the magnetization saturation state, and the interval of H s to H s is called the magnetization linear interval, and a constant inductance value is generated at both 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, both being N ; The magnetic permeability of the first magnetic core is equal to the magnetic permeability of the second magnetic core, both being ; The first magnetic core has a uniform overall shape, i.e., the area of each cross section perpendicular to the direction of the magnetic path in the first magnetic core is equal, and each cross section is ; The second magnetic core has a uniform overall shape, i.e., the area of each cross section perpendicular to the direction of the magnetic path in the second magnetic core is equal, and is ; The magnetic path length of the first coil is equal to the magnetic path length of the second coil, both being ; First, the magnetic sensitive element is placed in an environment without external magnetic field, and the first coil and the second coil are provided with the same size and opposite direction excitation current through an external circuit , to generate excitation magnetic field , to ensure that the magnetic sensitive element is located in the magnetization linear interval, and the inductance of the first coil and the inductance of the second coil are measured ;​ Then, the magnetic sensitive element is placed in an environment with an applied external magnetic field , while the first coil and the second coil are provided with the same size and opposite direction excitation current by an external circuit , the generated excitation magnetic field + is located in the magnetization linear interval, the inductance between the two ends of the first coil and the inductance between the two ends of the second coil are measured; The magnitude of the external magnetic field is obtained by , , , , specifically: 。 2. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The first magnetic core is made of soft magnetic material, and the second magnetic core is made of soft magnetic material.

3. The method for measuring an external magnetic field using a magnetic sensor element according to claim 2, wherein the magnetic sensor element is a giant magnetoresistance element. The soft magnetic material includes one or more of cobalt-based amorphous, iron-based amorphous, iron-based nanocrystalline, iron-nickel alloy, and iron-cobalt alloy.

4. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The material structure of the first magnetic core includes strip, wire, rod, and bulk.

5. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The material structure of the second magnetic core includes strip, wire, rod, and bulk.

6. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The cross section of the first magnetic core perpendicular to the magnetic force line is regular shape or irregular shape.

7. The method for measuring an external magnetic field using a magnetic sensor element according to claim 6, wherein the magnetic sensor element is a giant magnetoresistance element. The regular shape includes rectangle, circle, and polygon.

8. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The cross section of the second magnetic core perpendicular to the magnetic force line is regular shape or irregular shape.

9. The method for measuring an external magnetic field using a magnetic sensor element according to claim 8, wherein the magnetic sensor element is a giant magnetoresistive element. The regular shape includes rectangle, circle, and polygon.

10. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The shape of the cross section of the first magnetic core perpendicular to the magnetic force line is the same as or different from the shape of the cross section of the second magnetic core perpendicular to the magnetic force line.

11. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The first magnetic core and the second magnetic core are connected together or not connected together.

12. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. The first magnetic core and the second magnetic core are integrally formed.

13. The method for measuring an external magnetic field using a magnetic sensor element according to claim 1, wherein the magnetic sensor element is a giant magnetoresistance element. Controlling the cross-sectional area of the first magnetic core is equal to the cross-sectional area of the second magnetic core ​ 。 14. A magnetic sensor characterized by: The method for measuring external magnetic field by using magnetic sensitive element is adopted in any one of claims 1 to 13.

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