Temperature-drift-resistant magnetic sensor and magnetic field measurement method

Abstract

The invention relates to a temperature drift resistant magnetic sensor and a magnetic field measurement method. The magnetic sensor includes: a substrate; the spiral micro coil is arranged on the substrate and is used for generating a stable magnetic field environment; the plurality of magnetic sensitive units are arranged at different radius positions of the micro-coil, and each magnetic sensitive unit outputs a first output signal under the influence of a magnetic field and temperature; the non-magnetic sensing unit is arranged on the micro coil, and the non-magnetic sensing unit outputs a second output signal under the influence of the temperature; and the signal processing circuit is connected with each magnetic sensitive unit and the non-magnetic sensitive unit, and is used for outputting a measured value according to at least one first output signal and at least one second output signal. The method can improve the measurement precision and reliability of the magnetic sensor.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a temperature drift-resistant magnetic sensor and a magnetic field measurement method. Background Art

[0002] Magnetic sensors have broad application prospects in the fields of magnetic field measurement, geomagnetic navigation, nondestructive testing, power system monitoring, etc. due to their high sensitivity, wide linear range, low power consumption and small size. However, the performance stability of magnetic sensors in complex environments still faces severe challenges, especially changes in ambient temperature, which can cause zero drift (zero bias) in magnetic sensors, seriously restricting the measurement accuracy and reliability of magnetic sensors. Summary of the invention

[0003] Based on this, it is necessary to provide a magnetic sensor and a magnetic field measurement method that are resistant to temperature drift in order to address the above technical problems, so as to improve the measurement accuracy and reliability of the magnetic sensor.

[0004] In a first aspect, the present application provides a magnetic sensor resistant to temperature drift, the magnetic sensor comprising:

[0005] substrate;

[0006] A spiral microcoil, the microcoil is arranged on a substrate and is used to generate a stable magnetic field environment;

[0007] A plurality of magnetic sensitive units, each magnetic sensitive unit is arranged at a different radial position of the micro coil, and each magnetic sensitive unit outputs a first output signal under the influence of a magnetic field and temperature;

[0008] A non-magnetic sensitive unit, which is disposed on the micro-coil and outputs a second output signal under the influence of temperature;

[0009] The signal processing circuit is connected to each magnetic sensitive unit and the non-magnetic sensitive unit, and is used to output a measurement value according to at least one first output signal and a second output signal.

[0010] In one embodiment, the non-magnetic sensitive unit is located in the central area of ​​the micro-coil.

[0011] In one embodiment, the magnetic sensor further includes an insulating layer; the insulating layer is disposed between each magnetic sensitive unit and the micro-coil so that each magnetic sensitive unit does not contact the micro-coil and has a heat insulation effect.

[0012] In one of the embodiments, the magnetic sensor further includes a magnetic shielding layer; the magnetic shielding layer is disposed on a side of the non-magnetic sensitive unit away from the substrate to shield the magnetic field.

[0013] In one embodiment, the number of coil turns corresponding to different radii in the micro-coil increases in order from small to large radius.

[0014] In one embodiment, the signal processing circuit is used to perform weighted summation on the difference between each first output signal and the second output signal, and obtain the measurement value based on the summation result.

[0015] In one embodiment, the plurality of magnetically sensitive units include a first magnetically sensitive unit and a second magnetically sensitive unit; the first magnetically sensitive unit is close to the center of the micro-coil, and the second magnetically sensitive unit is far from the center of the micro-coil.

[0016] In one of the embodiments, in the case of a small range measurement, the signal processing circuit is used to obtain a measurement value according to a difference between a first output signal and a second output signal output by the first magnetic sensitive unit.

[0017] In one of the embodiments, in the case of a large-range measurement, the signal processing circuit is used to obtain a measurement value according to a difference between a first output signal and a second output signal output by the second magnetic sensitive unit.

[0018] In a second aspect, the present application provides a magnetic field measurement method, which is applied to the magnetic sensor described in any one of the first aspects above; the method comprises:

[0019] A plurality of magnetic sensitive units in the magnetic sensor measure and obtain a plurality of first output signals, each of which is output by each magnetic sensitive unit under the influence of a magnetic field and temperature;

[0020] The non-magnetic sensitive unit in the magnetic sensor measures and obtains a second output signal, where the second output signal is output by the non-magnetic sensitive unit under the influence of temperature;

[0021] The signal processing circuit in the magnetic sensor processes at least one of the first output signal and the second output signal to obtain a measurement value.

[0022] The above-mentioned magnetic sensor includes a substrate, a spiral microcoil, a plurality of magnetic sensitive units, a non-magnetic sensitive unit and a signal processing circuit, wherein the microcoil is arranged on the substrate to generate a stable magnetic field environment; each magnetic sensitive unit is arranged at a different radial position of the microcoil, and each magnetic sensitive unit outputs a first output signal under the influence of the magnetic field and temperature, in other words, the first output signal is related to the magnetic field and the temperature; the non-magnetic sensitive unit is arranged on the microcoil, and the non-magnetic sensitive unit outputs a second output signal under the influence of temperature, in other words, the second output signal is only related to the temperature; the signal processing circuit is connected to each magnetic sensitive unit and the non-magnetic sensitive unit, and is used to output a measurement value according to at least one first output signal and a second output signal, so that the measurement value obtained eliminates the temperature drift error, thereby improving the measurement accuracy and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A top view of a magnetic sensor resistant to temperature drift in one embodiment;

[0025] Figure 2 A top view of a magnetic sensor resistant to temperature drift in another embodiment;

[0026] Figure 3 A side view of a magnetic sensor resistant to temperature drift in one embodiment;

[0027] Figure 4 A schematic diagram of the working principle of a magnetic sensor resistant to temperature drift in one embodiment;

[0028] Figure 5 The working principle of a magnetic sensor resistant to temperature drift in another embodiment;

[0029] Figure 6 FIG. 4 is a flow chart of a magnetic field measurement method in an embodiment. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0031] At present, there are many types of magnetic sensors with magnetoresistance effect, such as GMR (Giant Magneto Resistance) magnetic sensors, TMR (Tunneling Magneto-Resistance) magnetic sensors, and AMR (Anisotropic Magneto-Resistance). These types of magnetic sensors have broad application prospects in magnetic field measurement, geomagnetic navigation, nondestructive testing, power system monitoring, etc. due to their high sensitivity, wide linear range, low power consumption, and small size. In particular, TMR magnetic sensors have attracted much attention due to their excellent performance. However, the performance stability of such magnetic sensors in complex environments still faces severe challenges. In particular, changes in ambient temperature will have a significant impact on the sensitivity and zero drift (zero bias) of the magnetic sensor, which seriously restricts the accuracy and reliability of magnetic field measurement.

[0032] Traditional temperature compensation methods usually use additional temperature sensors and processors to collect temperature information for compensation. However, this method has the following limitations: (1) Dependence on the characteristics of the temperature sensor: The repeatability and consistency of the temperature sensor are required to be high, and its measurement accuracy directly affects the effect of temperature drift suppression. (2) Indirect temperature measurement error: The temperature sensor can only measure the temperature changes of the sensor's external environment, but cannot accurately reflect the actual temperature changes inside the sensor, resulting in compensation errors. (3) Dynamic response lag: When the temperature changes rapidly, the compensation system may not respond quickly to the temperature change, which may easily lead to a decrease in compensation accuracy or even failure.

[0033] In addition, magnetic field measurement has a variety of application scenarios, and the range requirements for magnetic sensors vary greatly. Traditional magnetic sensors with a single range design are difficult to take into account both high-sensitivity measurements in a small magnetic field range and wide-range measurements in a large magnetic field range, limiting the applicability of magnetic sensors. The differences in characteristics of different types of magnetic sensitive units (such as GMR, TMR, and AMR) further increase the complexity of magnetic sensor design, and lack of compatibility becomes another difficulty in the design.

[0034] Therefore, traditional technologies have the following problems: (1) Insufficient multi-range design: Most magnetic sensor designs are only suitable for fixed ranges and cannot take into account the measurement requirements of small and large magnetic fields, resulting in insufficient flexibility of sensors in applications. (2) Limited temperature compensation capability: Traditional temperature compensation methods cannot reflect the temperature changes inside the sensor in real time, and the compensation lag and insufficient accuracy are prominent. (3) Poor compatibility: Different types of magnetic sensitive units have differences in material properties and output signal characteristics. Existing solutions are difficult to achieve unified compatibility and optimization of different magnetic sensitive units such as GMR, TMR, and AMR.

[0035] Based on this, it is necessary to propose effective technical means to solve the above technical problems. The technical solution of the present application and how the technical solution of the present application solves the above technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0036] In one embodiment, Figure 1 and Figure 2As shown, the present application provides a top view of a magnetic sensor resistant to temperature drift, the magnetic sensor comprising: a substrate 101, a spiral microcoil 102, a plurality of magnetic sensitive units 103, a non-magnetic sensitive unit 104 and a signal processing circuit 105. The microcoil 102 is arranged on the substrate 101 to generate a stable magnetic field environment; each magnetic sensitive unit 103 is arranged at a different radial position of the microcoil 102, and each magnetic sensitive unit 103 outputs a first output signal under the influence of a magnetic field and temperature; the non-magnetic sensitive unit 104 is arranged on the microcoil 102, and the non-magnetic sensitive unit 104 outputs a second output signal under the influence of temperature; the signal processing circuit 105 is connected to each magnetic sensitive unit 103 and the non-magnetic sensitive unit 104, and is used to output a measurement value according to at least one first output signal and a second output signal.

[0037] The substrate 101 is used to carry the micro coil 102 , each magnetic sensitive unit 103 and the non-magnetic sensitive unit 104 ; the material of the substrate 101 may be an insulating material.

[0038] The micro coil 102 is disposed on one side of the substrate 101 and is distributed in a planar spiral form. Specifically, the micro coil 102 may be in a circular spiral shape or a rectangular spiral shape. Figure 1 and Figure 2 The rectangular spiral shape is used as an example. The two ends of the micro coil 102 are connected to the positive and negative poles of the power supply respectively. The micro coil 102 covers the area of ​​each magnetic sensitive unit 103 and the non-magnetic sensitive unit 104, and is used to provide a stable magnetic field environment and perform dynamic compensation.

[0039] A plurality of magnetic sensitive units 103 may be arranged on a side of the microcoil 102 away from the substrate 101, and each magnetic sensitive unit 103 is arranged at a different radial position of the microcoil 102. The number of magnetic sensitive units 103 may be four, that is, the plurality of magnetic sensitive units 103 may include a pair of first magnetic sensitive units and a pair of second magnetic sensitive units, the pair of first magnetic sensitive units being close to the center of the microcoil 102, and the pair of second magnetic sensitive units being away from the center of the microcoil 102; the positions of the pair of first magnetic sensitive units on the microcoil 102 are the same as the center distance of the microcoil 102, and the two first magnetic sensitive units are arranged oppositely, the positions of the pair of second magnetic sensitive units on the microcoil 102 are the same as the center distance of the microcoil 102, and the two second magnetic sensitive units are arranged oppositely, as Figure 2 Of course, the number of magnetic sensitive units 103 can be two, that is, the plurality of magnetic sensitive units 103 can include a first magnetic sensitive unit and a second magnetic sensitive unit; the first magnetic sensitive unit is close to the center of the micro coil 102, and the second magnetic sensitive unit is far from the center of the micro coil 102, as shown in FIG. Figure 1As shown. Exemplarily, the first magnetic sensitive unit is disposed on a coil adjacent to the outermost coil in the micro coil 102 , and the second magnetic sensitive unit is disposed on the outermost coil of the micro coil 102 .

[0040] The magnetic sensitive unit 103 close to the center of the microcoil 102, that is, the magnetic sensitive unit 103 close to the inner circle of the microcoil 102, is suitable for small-range measurement; the magnetic sensitive unit 103 far from the center of the microcoil 102, that is, the magnetic sensitive unit 103 close to the outer circle of the microcoil 102, is suitable for large-range measurement.

[0041] In addition, the type of the magnetic sensitive unit 103 may be GMR, TMR or AMR, which outputs a first output signal under the influence of a magnetic field and temperature, that is, the first output signal is a signal related to the magnetic field and temperature.

[0042] The number of the non-magnetic sensitive unit 104 can be one or more. The non-magnetic sensitive unit 104 needs to be set in the same temperature environment as the magnetic sensitive unit 103 and is set in the shielding area on the micro coil. When there is only one non-magnetic sensitive unit 104, the non-magnetic sensitive unit 104 can be set in the central area of ​​the micro coil 102 away from the substrate 101, such as Figure 1 When there are multiple non-magnetic sensitive units 104, each non-magnetic sensitive unit 104 can be arranged one by one near each magnetic sensitive unit 103, such as Figure 2 Preferably, the number of the non-magnetic sensitive unit 104 is one, which is arranged in the central area of ​​the micro-coil 102 away from the substrate 101, because the temperature difference at different radial positions on the micro-coil 102 is not large, so only one non-magnetic sensitive unit 104 is arranged.

[0043] In addition, the non-magnetic sensitive unit 103 may be an MTJ (Magnetic Tunnel Junction) unit, which is only affected by temperature. Under the influence of temperature, the non-magnetic sensitive unit 103 outputs a second output signal, that is, the second output signal is a signal that is only related to temperature. The second output signal can be used as a reference signal for temperature drift compensation. It should be noted that the signal types output by each magnetic sensitive unit 103 and the non-magnetic sensitive unit 103 are the same.

[0044] The signal processing circuit 105 can be arranged around the micro coil 102, such as Figure 1 and Figure 2As shown. The signal processing circuit 105 includes a single chip microcomputer, which is connected to each magnetic sensitive unit 103 and non-magnetic sensitive unit 104 through a signal transmission line, and is used to perform weighted summation on the difference between each first output signal and the second output signal to obtain a measurement value. In one example, the signal processing circuit 105 performs weighted summation on the first output signal, and then subtracts the weighted summation result from the second output signal to obtain a measurement value. In another example, the signal processing circuit 105 selects one of the first output signals from multiple first output signals and subtracts it from the second output signal to obtain a measurement value. The measurement value can be the magnetic field strength.

[0045] The working principle of the above-mentioned temperature-drift-resistant magnetic sensor is as follows: the magnetic sensitive unit 103 senses the magnetic field under the action of the external magnetic field and outputs the first output signal V 磁 , the first output signal V 磁 Affected by both magnetic field and temperature. The non-magnetic sensitive unit 104 is not affected by the external magnetic field and only outputs a second output signal V related to temperature. 非磁 , the signal processing circuit 105 calculates the difference between the two, namely V 测量 =V 磁 -V 非磁 .

[0046] The above-mentioned temperature-drift-resistant magnetic sensor comprises: a substrate 101, a spiral micro-coil 102, a plurality of magnetic sensitive units 103, a non-magnetic sensitive unit 104 and a signal processing circuit 105. The micro-coil 102 is arranged on the substrate 101 to generate a stable magnetic field environment; each magnetic sensitive unit 103 is arranged at a different radius position of the micro-coil 102, and each magnetic sensitive unit 103 outputs a first output signal under the influence of the magnetic field and temperature; the non-magnetic sensitive unit 104 is arranged on the micro-coil 102, and the non-magnetic sensitive unit 104 outputs a second output signal under the influence of temperature; the signal processing circuit 105 is connected to each magnetic sensitive unit 103 and the non-magnetic sensitive unit 104, and is used to output a measurement value according to at least one first output signal and a second output signal, so that the measurement value obtained eliminates the temperature drift error, thereby improving the measurement accuracy and reliability.

[0047] In addition, the reference signal (i.e., the second output signal) is provided by the non-magnetic sensitive unit 104, and is directly compared with the output signal (i.e., the first output signal) of the magnetic sensitive unit 103 to achieve temperature drift elimination without the need for an additional reference magnetic field. Temperature drift compensation is directly completed in the signal, without the need for complex calculations and hysteresis, and has strong real-time performance. It also supports compatibility with GMR, TMR, and AMR, and different types of magnetic sensitive units can be configured according to needs, with high design flexibility.

[0048] In one embodiment, if Figure 3As shown, a side view of a magnetic sensor resistant to temperature drift is provided, and the magnetic sensor further includes an insulating layer 301; the insulating layer 301 is arranged between each magnetic sensitive unit 103 and the micro coil 102, so that each magnetic sensitive unit 103 does not contact the micro coil 102, and has a heat insulation effect. The insulating layer 301 is arranged to prevent each magnetic sensitive unit 103 from being connected to the micro coil 102, resulting in damage to the magnetic sensitive unit 103.

[0049] In one embodiment, continue to refer to Figure 3 As shown, the magnetic sensor further includes a magnetic shielding layer 302; the magnetic shielding layer 302 is disposed on a side of the non-magnetic sensitive unit 104 away from the substrate 101, and is used to shield the magnetic field. The magnetic shielding layer 302 is disposed to ensure that the non-magnetic sensitive unit 104 is not affected by the magnetic field.

[0050] In one embodiment, the number of coil turns corresponding to different radii in the micro coil 102 increases from small to large radius. In other words, expanding from the center to the outside, the number of turns of the spiral coil gradually increases from inside to outside, ensuring the uniformity of the magnetic field of the magnetic sensitive unit 103 at different radial positions.

[0051] In one embodiment, the signal processing circuit 105 is used to perform a weighted summation on the difference between each first output signal and the second output signal, and obtain a measurement value based on the summation result.

[0052] like Figure 4 As shown, the working principle of the temperature drift-resistant magnetic sensor is as follows:

[0053] Step 401, activating the micro coil 102 to generate a stable magnetic field working environment.

[0054] Step 402 : The signal processing circuit 105 collects the first output signals output by all magnetic sensitive units 103 , and collects the second output signals output by the non-magnetic sensitive units 104 .

[0055] Step 403: Subtract each first output signal from the second output signal to obtain a plurality of difference values, and perform weighted summation on the plurality of difference values ​​to obtain a measurement value.

[0056] In one embodiment, in the case of a small range measurement, the signal processing circuit is used to obtain a measurement value according to the difference between a first output signal and a second output signal output by the first magnetic sensitive unit. In the case of a large range measurement, the signal processing circuit is used to obtain a measurement value according to the difference between a first output signal and a second output signal output by the second magnetic sensitive unit.

[0057] like Figure 5 As shown, the working principle of the temperature drift-resistant magnetic sensor is as follows:

[0058] Step 501 : starting the first magnetic sensitive unit, the second magnetic sensitive unit and the signal processing circuit 105 according to the sensor configuration of the magnetic sensor.

[0059] Step 502: the signal processing circuit 105 detects whether the current external magnetic field value exceeds the measurement range of the first magnetic sensitive unit according to the first output signals of the first magnetic sensitive unit and the second magnetic sensitive unit.

[0060] Step 503: if it exceeds the measurement range of the first magnetic sensitive unit, the first magnetic sensitive unit is turned off, the second magnetic sensitive unit is enabled, and the measurement value is obtained according to the difference between the first output signal and the second output signal output by the second magnetic sensitive unit; if it does not exceed the measurement unit of the first magnetic sensitive unit, the second magnetic sensitive unit is turned off, the first magnetic sensitive unit is enabled, and the measurement value is obtained according to the difference between the first output signal and the second output signal output by the first magnetic sensitive unit.

[0061] It should be noted that, when the magnetic field changes, the magnetic sensor can switch between the first magnetic sensitive unit and the second magnetic sensitive unit in real time, or switch from the state of using only the first magnetic sensitive unit or only the second magnetic sensitive unit to the weighted fusion state, that is, switching or fusing the first output signal output by the magnetic sensitive unit 103 at different radial positions to achieve dynamic adjustment, which can ensure measurement accuracy and improve the reliability of the magnetic sensor.

[0062] This embodiment realizes combining the outputs of magnetic sensitive units 103 at different positions to achieve accurate measurement from small magnetic fields to large magnetic fields, that is, the magnetic sensor has the characteristic of multi-range measurement.

[0063] The application scenarios of the above-mentioned temperature drift-resistant magnetic sensor are as follows: in the geomagnetic navigation scenario, the magnetic sensor provides high-sensitivity measurement through the first magnetic sensitive unit to capture weak geomagnetic changes; when the magnetic sensor is close to a strong magnetic source, the second magnetic sensitive unit is automatically enabled to provide stable measurement in a large magnetic field range. The temperature drift compensation mechanism of the non-magnetic sensitive unit 104 ensures the measurement accuracy, and the magnetic sensor can still output accurate measurement values ​​even under extreme ambient temperature changes. Of course, the temperature drift-resistant magnetic sensor of the present application can also be applied to other fields, such as non-destructive testing and power equipment monitoring.

[0064] In one embodiment, Figure 6 As shown, the present application provides a flow chart of a magnetic field measurement method, which is applied to the magnetic sensor in any of the above magnetic sensor embodiments; the method comprises:

[0065] Step 601: a plurality of magnetic sensitive units in a magnetic sensor are measured to obtain a plurality of first output signals, each first output signal being output by each magnetic sensitive unit under the influence of a magnetic field and temperature.

[0066] Step 602: The non-magnetic sensitive unit in the magnetic sensor measures and obtains a second output signal, where the second output signal is output by the non-magnetic sensitive unit under the influence of temperature.

[0067] Step 603: The signal processing circuit in the magnetic sensor processes at least one of the first output signal and the second output signal to obtain a measurement value.

[0068] The specific implementation method has been described in detail in the above magnetic sensor embodiment and will not be repeated here.

[0069] In one embodiment, the present application also provides a method for preparing a magnetic sensor resistant to temperature drift, the preparation method comprising the following steps:

[0070] A planar spiral micro-coil 102 is formed on a substrate 101 , which can be manufactured by photolithography and metal deposition processes.

[0071] A plurality of magnetic sensitive units 103 are deposited on the micro coil 102 according to a predetermined radius distribution, and the type of the magnetic sensitive unit 103 can be GMR, TMR or AMR;

[0072] A non-magnetic sensitive unit 104 is arranged in the central area of ​​the micro coil 102 and connected to a signal processing circuit 105;

[0073] Performing an initial calibration on all magnetic sensitive units 103 to determine their range and sensitivity;

[0074] The current control parameters of the micro-coil 102 are tested and adjusted to optimize the dynamic response capability of the compensation magnetic field.

[0075] In summary, magnetic sensors that are resistant to temperature drift include:

[0076] A substrate 101 is used to carry a micro coil 102 and a magnetic sensitive unit 103;

[0077] The micro coil 102 is arranged on the substrate 101 in a planar spiral form and is used to generate a reference magnetic field and a compensation magnetic field;

[0078] A plurality of magnetic sensitive units 103 are arranged at different radial positions of the micro coil 102 for measuring magnetic field signals of different ranges; the magnetic sensitive units may be of GMR, TMR or AMR type;

[0079] The non-magnetic sensitive unit 104 is arranged in the central area of ​​the micro-coil 102, and adopts the same size and technical solution as the magnetic sensitive unit 103. A magnetic shielding layer 302 is used on the top to ensure that it is not affected by the external magnetic field, and is used to provide a reference signal to correct the temperature drift;

[0080] The signal processing circuit 105 is used to receive the first output signal of the magnetic sensitive unit 103 and the second output signal of the non-magnetic sensitive unit 104, and realize real-time compensation and correction.

[0081] Among them, multiple magnetic sensitive units 103 are arranged in sequence from the inner radius to the outer radius of the micro coil 102, and the magnetic sensitive units at different radial positions correspond to different measuring ranges; the magnetic sensitive units 103 at the inner radius are used for small magnetic field range measurement, and the magnetic sensitive units 103 at the outer radius are used for large magnetic field range measurement.

[0082] The second output signal (i.e., the reference signal) of the non-magnetic sensitive unit 104 is compared with the first output signal of the magnetic sensitive unit 103 in real time. When the comparison is consistent, the compensation magnetic field is dynamically adjusted through the micro coil 102. The magnitude of the compensation magnetic field is the actual value of the magnetic field to be measured.

[0083] The magnetic field measurement method comprises the following steps: generating a reference magnetic field of constant frequency and amplitude through the microcoil 102 and applying it to the area where the plurality of magnetic sensitive units 103 are located;

[0084] At the same time, the first output signals of multiple magnetic sensitive units 103 are collected through the signal processing circuit 105, and each first output signal is compared with the second output signal of the non-magnetic sensitive unit; according to the size of the first output signal of the magnetic sensitive unit 103, the micro coil 102 is used to generate a compensation magnetic field to adjust the changes in the external magnetic field in real time.

[0085] When the first output signal of the magnetic sensitive unit 103 is consistent with the second output signal of the non-magnetic sensitive unit 104, the induced magnetic field is considered to be zero, and the compensation magnetic field generated at this time is the measured value of the external magnetic field. The type of the magnetic sensitive unit 103 can be selected as GMR, TMR or AMR, and the appropriate type of sensing unit is selected according to the application requirements to meet the measurement requirements; the compensation magnetic field is generated in real time through closed-loop control to eliminate environmental temperature drift and interference signals.

[0086] The measurement process combines the sensitivity of the magnetic sensitive unit 103 at different radial positions and calculates a unified accurate magnetic field value through a weighted summation algorithm.

[0087] When any magnetic sensitive unit 103 is abnormal, correction is performed using the first output signals of other magnetic sensitive units 103 and the signals of the non-magnetic sensitive units 104 .

[0088] The number of turns and wire width of the microcoil are optimized according to different measuring ranges to ensure that a uniform and stable reference magnetic field is generated at different radial positions; the microcoil adopts a multi-layer structure to reduce the volume and increase the magnetic field strength.

[0089] The non-magnetic sensitive unit 104 is arranged in the central area of ​​the micro-coil and covered with a magnetic shielding layer to minimize the interference of the external magnetic field;

[0090] The second output signal of the non-magnetic sensitive unit 104 may be processed by digital filtering to improve the stability of the reference signal.

[0091] The output signal of the magnetic sensitive unit 103 is transmitted to the signal processing circuit through an independent channel to avoid coupling between signals of different ranges;

[0092] The signal processing circuit 105 collects signals from each channel in real time through an analog-to-digital conversion module, and adjusts the compensation magnetic field of the micro-coil 102 in combination with a closed-loop control algorithm.

[0093] The magnetic field measurement process can dynamically select different magnetic sensitive units 103 to participate in the measurement to match the range of the magnetic field to be measured. In addition, the magnetic sensor can also dynamically optimize the linearity and accuracy of the output signal through a signal fusion algorithm.

[0094] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0095] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0096] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0097] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0098] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0099] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0100] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0101] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0102] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A magnetic sensor resistant to temperature drift, characterized in that: The magnetic sensor comprises: substrate; A spiral microcoil, the microcoil being disposed on the substrate and used to generate a stable magnetic field environment; A plurality of magnetic sensitive units, each of which is arranged at a different radial position of the micro-coil, and each of which outputs a first output signal under the influence of a magnetic field and temperature; a non-magnetic sensitive unit, the non-magnetic sensitive unit being arranged on the micro-coil, and the non-magnetic sensitive unit outputting a second output signal under the influence of temperature; A signal processing circuit is connected to each of the magnetic sensitive units and the non-magnetic sensitive units, and is used to output a measurement value according to at least one of the first output signal and the second output signal.

2. The magnetic sensor according to claim 1, characterized in that The non-magnetic sensitive unit is located in the central area of ​​the micro coil.

3. The magnetic sensor according to claim 1, characterized in that The magnetic sensor further comprises an insulating layer; The insulating layer is arranged between each of the magnetic sensitive units and the micro coil so that each of the magnetic sensitive units does not contact the micro coil and has a heat insulation effect.

4. The magnetic sensor according to claim 1, characterized in that The magnetic sensor further comprises a magnetic shielding layer; The magnetic shielding layer is arranged on a side of the non-magnetic sensitive unit away from the substrate, and is used for shielding the magnetic field.

5. The magnetic sensor according to claim 1, characterized in that The number of coil turns corresponding to different radii in the micro-coil increases in order from small to large radius.

6. The magnetic sensor according to any one of claims 1 to 5, characterized in that: The signal processing circuit is used to perform weighted summation on the differences between the first output signals and the second output signals, and obtain the measurement value based on the summation result.

7. The magnetic sensor according to any one of claims 1 to 5, characterized in that: The plurality of magnetically sensitive units include a first magnetically sensitive unit and a second magnetically sensitive unit; the first magnetically sensitive unit is close to the center of the micro-coil, and the second magnetically sensitive unit is far from the center of the micro-coil.

8. The magnetic sensor according to claim 7, characterized in that: In the case of a small-range measurement, the signal processing circuit is used to obtain the measurement value according to the difference between the first output signal output by the first magnetic sensitive unit and the second output signal.

9. The magnetic sensor according to claim 7, characterized in that: In the case of a large-range measurement, the signal processing circuit is used to obtain the measurement value according to the difference between the first output signal and the second output signal output by the second magnetic sensitive unit.

10. A magnetic field measurement method, characterized in that: The method is applied to the magnetic sensor according to any one of claims 1 to 9; the method comprises: A plurality of magnetic sensitive units in the magnetic sensor measure and obtain a plurality of first output signals, each of the first output signals being output by each of the magnetic sensitive units under the influence of a magnetic field and temperature; The non-magnetic sensitive unit in the magnetic sensor measures and obtains a second output signal, where the second output signal is output by the non-magnetic sensitive unit under the influence of temperature; The signal processing circuit in the magnetic sensor processes at least one of the first output signal and the second output signal to obtain a measurement value.

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