Magnetic modulation current sensor and current measurement system

Abstract

The invention relates to a magnetic modulation current sensor and a current measurement system. The magnetic modulation current sensor comprises a signal source, a modulation sensing assembly and a signal processing circuit, the signal source is used for providing alternating current signals, the magnetic modulation sensing assembly comprises a fixing piece, a plurality of bias units and a plurality of magnetic modulation units, the fixing piece is provided with a through hole used for arranging a wire to be detected, and the bias units are arranged in the through hole. The plurality of bias units are arranged on the fixed part at intervals and form a loop by taking any point on the axis of the wire to be measured as a central point, each bias unit is used for generating a bias magnetic field according to an alternating current signal, and each magnetic modulation unit is correspondingly positioned in each bias unit; each magnetic modulation unit is used for outputting an initial detection signal according to a bias magnetic field generated by the corresponding bias unit and an induced magnetic field generated by a to-be-detected current transmitted by the to-be-detected wire, and the signal processing circuit is used for determining the to-be-detected current according to the initial detection signal of each magnetic modulation unit. The magnetic modulation current sensor provided by the invention has relatively high detection precision.

Description

Technical Field

[0001] The present application relates to the technical field of current measurement, and in particular to a magnetic modulation current sensor and a current measurement system. Background Art

[0002] With the development of science and technology, magnetic modulation current sensors are widely used in power systems, motor drives, new energy, electric vehicles and other fields, providing important support for the intelligence and efficiency of related systems.

[0003] However, the magnetic modulation current sensor in the related art still has the problem of low measurement accuracy. Summary of the invention

[0004] Based on this, it is necessary to provide a magnetic modulation current sensor and a current measurement system with high measurement accuracy to address the above technical problems.

[0005] In a first aspect, the present application provides a magnetic modulation current sensor, the magnetic modulation current sensor comprising:

[0006] A signal source, used for providing an alternating current signal;

[0007] A magnetic modulation sensing assembly, comprising a fixing member, a plurality of bias units and a plurality of magnetic modulation units, wherein the fixing member comprises a through hole, the through hole is used to set a conductor to be measured, a plurality of bias units are arranged on the fixing member at intervals, and the plurality of bias units form a loop with any point on the axis of the conductor to be measured as the center point, each bias unit is connected to the signal source, the bias unit is used to generate a bias magnetic field according to the alternating current signal, each magnetic modulation unit is respectively located in each bias unit, and the magnetic modulation unit is used to output an initial detection signal according to the bias magnetic field generated by the corresponding bias unit and the induced magnetic field generated by the current to be measured transmitted by the conductor to be measured;

[0008] The signal processing circuit is connected to each of the magnetic modulation units, and is used to determine the current to be measured according to the initial detection signal of each of the magnetic modulation units.

[0009] In one embodiment, the bias unit comprises:

[0010] A hollow casing, wherein the magnetic modulation unit is located in the hollow casing;

[0011] A bias coil is connected to the signal source and is wound around the inner and outer walls of the hollow casing. The bias coil is used to receive the alternating current signal output by the signal source and generate a bias magnetic field according to the alternating current signal, wherein the bias magnetic field is used to eliminate the intrinsic noise of the magnetic modulation unit.

[0012] In one of the embodiments, the magnetic modulation sensing component further includes a power supply unit; the magnetic modulation unit includes a Wheatstone circuit, and the Wheatstone circuit is used to output an initial detection signal according to the induced magnetic field and the bias magnetic field under the power supply of the power supply unit.

[0013] In one of the embodiments, the Wheatstone circuit includes a first tunneling magnetoresistance, a second tunneling magnetoresistance, a third tunneling magnetoresistance, and a fourth tunneling magnetoresistance;

[0014] The first end of the first tunneling magnetoresistance and the first end of the second tunneling magnetoresistance are respectively connected to the first end of the power supply unit, the first end of the third tunneling magnetoresistance and the first end of the fourth tunneling magnetoresistance are respectively connected to the second end of the power supply unit, the second end of the first tunneling magnetoresistance is connected to the second end of the fourth tunneling magnetoresistance, and the second end of the second tunneling magnetoresistance is connected to the second end of the third tunneling magnetoresistance;

[0015] The midpoint between the first tunneling magnetoresistance and the fourth tunneling magnetoresistance and the midpoint between the second tunneling magnetoresistance and the third tunneling magnetoresistance are used to output an initial detection signal.

[0016] In one embodiment, the signal processing circuit comprises:

[0017] an operational amplifier unit, connected to each of the magnetic modulation sensing units, and used for averaging and amplifying each of the initial detection signals to generate a target detection signal;

[0018] The filtering unit is connected to the operational amplifier unit and is used to filter the target detection signal and output a detection result.

[0019] In one embodiment, the operational amplifier unit includes:

[0020] an operational amplifier, wherein the positive input terminal of the operational amplifier is respectively connected to the output terminal of each of the magnetic modulation units, the output terminal of the operational amplifier is connected to the filtering unit, and the operational amplifier is used to average and amplify each of the initial detection signals and output a target detection signal;

[0021] a first resistor, wherein a first end of the first resistor is connected to the negative input end of the operational amplifier, and a second end of the first resistor is grounded;

[0022] A second resistor, wherein a first end of the second resistor is connected to the negative input end of the operational amplifier, and a second end of the second resistor is respectively connected to the output end of the operational amplifier and the filtering unit.

[0023] In one embodiment, the filtering unit comprises:

[0024] A low-pass filter is connected to the operational amplifier unit and is used to filter out the signal of a preset frequency in the target detection signal and output a detection result, wherein the preset frequency is the frequency of the alternating current signal.

[0025] In one of the embodiments, the fixing member comprises a fixing ring, each of the biasing units is evenly arranged on the fixing ring, and the center of the fixing ring is located on the axis of the conductor to be tested.

[0026] In one of the embodiments, the magnetic modulation current sensor further includes: a shell, the shell is connected to the fixing member, and the signal source and the signal processing circuit are located in the shell.

[0027] In a second aspect, the present application provides a current measurement system, the system comprising a conductor to be measured and the magnetic modulation current sensor described in any one of the above embodiments.

[0028] The above-mentioned magnetic modulation current sensor and current measurement system include a signal source, a modulation sensing component and a signal processing circuit. The signal source is used to provide an alternating current signal. The magnetic modulation sensing component includes a fixing part, multiple bias units and multiple magnetic modulation units. The fixing part includes a through hole, and the through hole is used to set the conductor to be measured. The multiple bias units are arranged on the fixing part at intervals, and the multiple bias units form a loop with any point on the axis of the conductor to be measured as the center point. Each bias unit is connected to the signal source. The bias unit is used to generate a bias magnetic field according to the alternating current signal. Each magnetic modulation unit is respectively located in each bias unit. The magnetic modulation unit is used to output an initial detection signal according to the bias magnetic field generated by the corresponding bias unit and the induced magnetic field generated by the current to be measured transmitted by the conductor to be measured. The signal processing circuit is respectively connected to each magnetic modulation unit to determine the current to be measured according to the initial detection signal of each magnetic modulation unit. In the present application, each magnetic modulation unit is respectively arranged in each bias unit, and an alternating current signal is applied to the bias unit through a signal source, so that the bias unit can generate a bias magnetic field. Under the action of the bias magnetic field, the flicker noise of the magnetic modulation unit itself, that is, the low-frequency magnetic 1 / f noise is suppressed, thereby making the detection result of the magnetic modulation current sensor more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A schematic diagram of the structure of a magnetic modulation current sensor in one embodiment;

[0031] Figure 2 is a schematic structural diagram of a bias unit in one embodiment;

[0032] Figure 3 is a schematic diagram of the structure of a Wheatstone bridge in one embodiment;

[0033] Figure 4 is a schematic structural diagram of a magnetic modulation current sensor in another embodiment;

[0034] Figure 5 is a schematic diagram of a flow chart of an operational amplifier unit in one embodiment;

[0035] Figure 6 FIG. 4 is a schematic diagram of the structure of a magnetic modulation current sensor in another embodiment. DETAILED DESCRIPTION

[0036] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0038] It can be understood that the terms "first", "second", etc. used in the present application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0039] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0040] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is transmission of electrical signals or data between the connected objects.

[0041] 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.

[0042] With the gradual development of my country's economy and the gradual implementation of new energy planning, electricity, as an important secondary energy source, has gradually become more important in my country's energy system, and the proportion of electric energy applications has gradually increased. In this context, the current size and voltage level in the power system are gradually increasing. In order to effectively ensure the safe operation of electric energy, it is necessary to achieve precise control of power resources. The basis for achieving precise control is to be able to obtain accurate measurement values ​​of the power system operation, so further research on current sensors is necessary.

[0043] The current sensors in the related technology are mainly divided into contact current sensors and non-contact current sensors. The contact current sensor mainly measures the current indirectly by measuring the voltage drop of the sampling resistor through the sampling resistor. The non-contact current sensor mainly uses the principle of electromagnetic induction to convert the magnetic signal carried by the electrical signal itself into an electrical signal, and then measures it to achieve electrical isolation. Since the coreless magnetic modulation current sensor has no core to converge the magnetic field near the current, the measured magnetic field may change due to the position between the wire and the magnetic modulation chip, and there are shot noise, magnetothermal noise, electronic 1 / f noise and magnetic 1 / f noise in the magnetic modulation chip. Among them, the magnetic 1 / f noise at low frequency is the main noise of the magnetic modulation chip. The amplitude of the low-frequency magnetic 1 / f noise is large, which will affect the accuracy of the current measurement when using the magnetic modulation current sensor for current measurement.

[0044] In order to solve the above technical problems, the present application provides a magnetic modulation current sensor, please refer to Figure 1 The magnetic modulation current sensor includes: a signal source 1, a magnetic modulation sensing component 2 and a signal processing circuit 3.

[0045] Among them, the signal source 1 is used to provide an alternating current signal. The magnetic modulation sensing assembly 2 includes a fixing member 21, a plurality of bias units 22 and a plurality of magnetic modulation units 23. The fixing member 21 has a through hole, and the through hole is used to set the conductor to be measured. The plurality of bias units 22 are arranged on the fixing member 21 at intervals, and the plurality of bias units 22 form a loop with any point on the axis of the conductor to be measured 4 as the center point. Each bias unit 22 is respectively connected to the signal source 1. The bias unit 22 is used to generate a bias magnetic field according to the alternating current signal. Each magnetic modulation unit 23 is respectively located in each bias unit 22. The magnetic modulation unit 23 is used to output an initial detection signal according to the bias magnetic field generated by the corresponding bias unit and the induced magnetic field generated by the current to be measured transmitted by the conductor to be measured. The signal processing circuit 3 is respectively connected to each magnetic modulation unit 23, and is used to determine the current to be measured according to the initial detection signal of each magnetic modulation unit 23.

[0046] In this embodiment, the number of bias units 22 and magnetic modulation units 23 is the same, each bias unit 22 is arranged on the fixing member 21 at intervals, and each magnetic modulation unit 23 is arranged in each bias unit 22. When the magnetic modulation current sensor of the present application is used for current detection, the conductor 4 to be measured is first placed at the center of the through hole of the fixing member 21, so that multiple bias units 22 can form a loop with any point on the axis of the conductor 4 to be measured as the center point, and then the signal source 1 is turned on, and the signal source 1 is connected to each bias unit 22 respectively. The signal source 1 can send a sinusoidal AC signal to each bias unit 22 by self-excited oscillation. Under the action of the AC signal, the bias unit 22 will generate a sinusoidal bias magnetic field. Under the action of the sinusoidal bias magnetic field, the low 1 / f noise of the magnetic modulation unit 23 can be suppressed. In addition, the inventor found through experiments that when the frequency of the sine wave is 2k, the sinusoidal bias magnetic field has the best suppression effect on low-frequency magnetic 1 / f noise.

[0047] At the same time, when an AC current to be measured flows through the test conductor 4, the current to be measured will also generate an induced magnetic field based on electromagnetic induction, wherein the frequency of the current to be measured is different from the frequency of the AC signal. The magnetic modulation unit 23 can detect the bias magnetic field and the induced magnetic field, and under the action of the bias magnetic field and the induced magnetic field, output an initial detection signal to the signal processing circuit 3. Since the frequencies of the bias magnetic field and the induced magnetic field are different, the signal processing circuit 3 can filter out the part of the initial detection signal generated based on the bias magnetic field to obtain an accurate detection result.

[0048] The above-mentioned magnetic modulation current sensor includes a signal source, a modulation sensing component and a signal processing circuit. The signal source is used to provide an alternating current signal. The magnetic modulation sensing component includes a fixing part, multiple bias units and multiple magnetic modulation units. The fixing part includes a through hole, and the through hole is used to set the conductor to be measured. The multiple bias units are arranged on the fixing part at intervals, and the multiple bias units form a loop with any point on the axis of the conductor to be measured as the center point. Each bias unit is connected to the signal source. The bias unit is used to generate a bias magnetic field according to the alternating current signal. Each magnetic modulation unit is respectively located in each bias unit. The magnetic modulation unit is used to output an initial detection signal according to the bias magnetic field generated by the corresponding bias unit and the induced magnetic field generated by the current to be measured transmitted by the conductor to be measured. The signal processing circuit is respectively connected to each magnetic modulation unit to determine the current to be measured according to the initial detection signal of each magnetic modulation unit. In the present application, each magnetic modulation unit is respectively arranged in each bias unit, and an alternating current signal is applied to the bias unit through a signal source, so that the bias unit can generate a bias magnetic field. Under the action of the bias magnetic field, the flicker noise of the magnetic modulation unit itself, that is, the low-frequency magnetic 1 / f noise is suppressed, thereby making the detection result of the magnetic modulation current sensor more accurate.

[0049] In an exemplary embodiment, see Figure 2 The bias unit 22 includes a hollow sleeve 221 and a bias coil 222 .

[0050] Among them, the magnetic modulation unit 23 is arranged in the hollow sleeve 221, the bias coil 222 is connected to the signal source 1 and is wound around the inner wall and the outer wall of the hollow sleeve 221, and the bias coil 222 is used to receive the alternating current signal output by the signal source 1 and generate a bias magnetic field according to the alternating current signal, wherein the bias magnetic field is used to eliminate the intrinsic noise of the magnetic modulation unit.

[0051] In this embodiment, the hollow sleeve 221 may be made of a material with high magnetic permeability. For example, the magnetic permeability of the hollow sleeve 221 may be equal to or greater than ten thousand times the magnetic permeability of a vacuum. Figure 2 The bias coil 222 is wound around the inner and outer walls of the hollow sleeve 221 in the manner shown. When a sinusoidal alternating current signal flows through the bias coil 222, a sinusoidal bias magnetic field is generated around the hollow sleeve 221. Since the magnetic modulation unit 23 is arranged inside the hollow sleeve 221, the magnetic modulation unit 23 can be completely in the sinusoidal bias magnetic field. When the magnetic modulation unit 23 is working, its own low-frequency magnetic 1 / f noise can be suppressed under the action of the sinusoidal bias magnetic field.

[0052] In an exemplary embodiment, see Figure 3The magnetic modulation sensing assembly 2 further includes a power supply unit 24. The magnetic modulation unit 23 includes a Wheatstone circuit 231, which is used to output an initial detection signal V0 according to the induced magnetic field and the bias magnetic field under the power supply of the power supply unit 24.

[0053] from Figure 3 As can be seen from FIG. 1 , the Wheatstone circuit includes a first tunneling magnetoresistance R1 , a second tunneling magnetoresistance R2 , a third tunneling magnetoresistance R3 and a fourth tunneling magnetoresistance R4 .

[0054] The first end of the first tunneling magnetic resistor R1 and the first end of the second tunneling magnetic resistor R2 are respectively connected to the first end of the power supply unit 24, the first end of the third tunneling magnetic resistor R3 and the first end of the fourth tunneling magnetic resistor R3 are respectively connected to the second end of the power supply unit 24, the second end of the first tunneling magnetic resistor R1 is connected to the second end of the fourth tunneling magnetic resistor R4, and the second end of the second tunneling magnetic resistor R2 is connected to the second end of the third tunneling magnetic resistor R3. The midpoint of the first tunneling magnetic resistor R1 and the fourth tunneling magnetic resistor R4 and the midpoint of the second tunneling magnetic resistor R2 and the third tunneling magnetic resistor R3 are used to output the initial detection signal V0.

[0055] In application, when there is no external magnetic field, the resistance values ​​of the four tunneling magnetoresistances are equal, the Wheatstone bridge is in a balanced state, and the output voltage is 0. When an AC current to be measured flows through the test conductor 4, the current to be measured will generate an induced magnetic field based on electromagnetic induction. When an AC signal flows through the bias coil, the AC signal will generate a bias magnetic field based on electromagnetic induction. The magnetization direction of the free layer of each tunneling magnetoresistance will change. This change will affect the tunnel barrier of the tunneling magnetoresistance, and then change the resistance value of the tunneling magnetoresistance, so that a differential signal that changes linearly with the current to be measured and the AC signal is output at the output end of the Wheatstone bridge, that is, the initial detection signal V0. In one example, the magnetic modulation unit 23 is a magnetic modulation chip.

[0056] In an exemplary embodiment, see Figure 4 The signal processing circuit 3 includes an operational amplifier unit 31 and a filter unit 32 .

[0057] The operational amplifier unit 31 is connected to each magnetic modulation sensor unit, and is used to average and amplify each initial detection signal to generate a target detection signal. The filter unit 32 is connected to the operational amplifier unit 31, and is used to filter the target detection signal and output a detection result.

[0058] In this embodiment, in order to improve the measurement accuracy and avoid external interference, a plurality of magnetic modulation units 23 can be set in the magnetic modulation sensor assembly 2, the number of magnetic modulation units 23 is an even number and the magnetic modulation units 23 are symmetrically arranged in pairs. In the application, the optimal number and spacing of the magnetic modulation units 23 can be optimized and designed according to the specific application scenario and requirements. For each magnetic modulation unit 23, a bias unit 22 is correspondingly set, so that the magnetic modulation unit 23 is correspondingly located in the bias unit 22, so that each bias unit 22 suppresses the low-frequency magnetic 1 / f noise of the corresponding magnetic modulation unit 23.

[0059] When there are multiple magnetic modulation units 23, the operational amplifier unit needs to average the multiple initial detection signals received to obtain the average value of each initial detection signal. In the process of signal transmission, the initial detection signal will be attenuated due to factors such as distance and obstacles, so it is also necessary to amplify each initial detection signal to make it strong enough for subsequent processing and transmission, and finally obtain the target detection signal. Among them, each magnetic modulation unit 23 is connected to the operational amplifier unit through a wire, and the wire length connecting each magnetic modulation unit 23 and the operational amplifier unit is the same.

[0060] It can be understood that since the initial detection signal is generated based on the bias magnetic field and the induced magnetic field, in order to obtain accurate test results of the current to be measured, it is necessary to eliminate the influence of the bias magnetic field on the measurement results. Therefore, in the present application, a filter unit 32 is also provided after the operational amplifier unit 31. The filter unit 32 can be a low-pass filter. The low-pass filter is connected to the operational amplifier unit 31, and is used to filter out the signal of a preset frequency in the target detection signal, that is, to eliminate the signal with the same frequency as the bias magnetic field in the target detection signal, and output the detection result.

[0061] In addition, during the signal transmission process, the signal is often interfered by various noises, which may contain high-frequency components. Low-pass filters can help remove these high-frequency noises, thereby improving the signal-to-noise ratio of the signal, removing spikes and glitches in the signal, making the signal smoother, and filtering out unnecessary frequency components, retaining only the useful parts, making the output signal cleaner.

[0062] In an exemplary embodiment, see Figure 5 The operational amplifier unit includes an operational amplifier V1, a first resistor R5 and a second resistor R6.

[0063] The positive input terminal of the operational amplifier V1 is connected to the output terminal of each magnetic modulation unit 23, the output terminal of the operational amplifier V1 is connected to the filter unit 32, the first end of the first resistor R5 is connected to the negative input terminal of the operational amplifier V1, and the second end of the first resistor R5 is grounded. The first end of the second resistor R6 is connected to the negative input terminal of the operational amplifier V1, and the second end of the second resistor R6 is connected to the output terminal of the operational amplifier V1 and the filter unit 32.

[0064] It can be understood that, assuming that the magnetic modulation sensor assembly includes n magnetic modulation units, the positive input terminal of the operational amplifier V1 is connected to the output terminal of each magnetic modulation unit to receive the initial detection signal V output by each magnetic modulation unit. 01 ~V 0n The operational amplifier V1 is used to average and amplify each initial detection signal and output a target detection signal. The amplification factor of the operational amplifier V1 can be controlled by setting the size of the first resistor R5 and the second resistor R6.

[0065] In addition, there may be a resistor R between the positive input terminal of the operational amplifier V1 and the output terminal of each magnetic modulation unit. x1 ~R xn , so that the impedance between each magnetic modulation unit and the operational amplifier V1 can be matched, thereby improving signal quality and transmission efficiency.

[0066] In an exemplary embodiment, see Figure 6 The fixing member 21 includes a fixing ring 211, each bias unit 22 is evenly arranged on the fixing ring 211, each magnetic modulation unit 23 is respectively located in the corresponding bias unit 22, and the magnetic modulation current sensor also includes a housing 5, the housing 5 is connected to the fixing member 21, and the signal source 1 and the signal processing circuit 3 are located in the housing 5 ( Figure 6 The signal source 1 and the signal processing circuit 3 are not shown in the figure). The fixing ring 211 is arranged on one side of the housing 5. The housing 5 also has a plurality of electrical interfaces, each of which is arranged at the bottom of the housing 5, that is, on the side of the housing 5 opposite to the fixing ring 211. In one example, each electrical interface can be respectively connected to the positive power supply interface, the negative power supply interface, the ground interface and the measurement output port.

[0067] In this example, only four bias units 22 and four magnetic modulation units 23 are installed on the fixed ring 221. In application, the number of bias units 22 and magnetic modulation units 23 on the fixed ring 221 can be adjusted according to specific needs. When the magnetic modulation current sensor of the present application is used for current detection, it is only necessary to place the conductor 4 to be measured at the center of the fixed ring 211, and the magnetic modulation unit 23 can output an initial detection signal under the action of the bias magnetic field and the induced magnetic field, and the low-frequency magnetic 1 / f noise of the magnetic modulation unit 23 itself is suppressed under the action of the bias magnetic field. The subsequent signal processing circuit can average and amplify the initial detection signal, and filter out the component generated based on the bias magnetic field, so that the final output result is only based on the component generated by the induced magnetic field generated by the current to be measured, thereby improving the accuracy of the output result.

[0068] In an exemplary embodiment, the present application provides a current measurement system, which includes a conductor to be measured and a magnetic modulation current sensor according to any one of the above embodiments.

[0069] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0070] 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 specification.

[0071] The above-mentioned 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 invention patent. 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 patent of the present application shall be subject to the attached claims.

Claims

1. A magnetic modulation current sensor, characterized in that: The magnetic modulation current sensor comprises: A signal source, used for providing an alternating current signal; A magnetic modulation sensing assembly, comprising a fixing member, a plurality of bias units and a plurality of magnetic modulation units, wherein the fixing member comprises a through hole, the through hole is used to set a conductor to be measured, a plurality of bias units are arranged on the fixing member at intervals, and the plurality of bias units form a loop with any point on the axis of the conductor to be measured as the center point, each bias unit is connected to the signal source, the bias unit is used to generate a bias magnetic field according to the alternating current signal, each magnetic modulation unit is respectively located in each bias unit, and the magnetic modulation unit is used to output an initial detection signal according to the bias magnetic field generated by the corresponding bias unit and the induced magnetic field generated by the current to be measured transmitted by the conductor to be measured; The signal processing circuit is connected to each of the magnetic modulation units, and is used to determine the current to be measured according to the initial detection signal of each of the magnetic modulation units.

2. The magnetic modulation current sensor according to claim 1, characterized in that: The bias unit comprises: A hollow casing, wherein the magnetic modulation unit is located in the hollow casing; A bias coil is connected to the signal source and is wound around the inner and outer walls of the hollow casing. The bias coil is used to receive the alternating current signal output by the signal source and generate a bias magnetic field according to the alternating current signal, wherein the bias magnetic field is used to eliminate the intrinsic noise of the magnetic modulation unit.

3. The magnetic modulation current sensor according to claim 1, characterized in that: The magnetic modulation sensing component also includes a power supply unit; the magnetic modulation unit includes a Wheatstone circuit, and the Wheatstone circuit is used to output an initial detection signal according to the induced magnetic field and the bias magnetic field under the power supply of the power supply unit.

4. The magnetic modulation current sensor according to claim 3, characterized in that: The Wheatstone circuit includes a first tunneling magnetoresistance, a second tunneling magnetoresistance, a third tunneling magnetoresistance and a fourth tunneling magnetoresistance; The first end of the first tunneling magnetoresistance and the first end of the second tunneling magnetoresistance are respectively connected to the first end of the power supply unit, the first end of the third tunneling magnetoresistance and the first end of the fourth tunneling magnetoresistance are respectively connected to the second end of the power supply unit, the second end of the first tunneling magnetoresistance is connected to the second end of the fourth tunneling magnetoresistance, and the second end of the second tunneling magnetoresistance is connected to the second end of the third tunneling magnetoresistance; The midpoint between the first tunneling magnetoresistance and the fourth tunneling magnetoresistance and the midpoint between the second tunneling magnetoresistance and the third tunneling magnetoresistance are used to output an initial detection signal.

5. The magnetic modulation current sensor according to claim 1, characterized in that: The signal processing circuit comprises: an operational amplifier unit, connected to each of the magnetic modulation sensing units, and used for averaging and amplifying each of the initial detection signals to generate a target detection signal; The filtering unit is connected to the operational amplifier unit and is used to filter the target detection signal and output a detection result.

6. The magnetic modulation current sensor according to claim 5, characterized in that: The operational amplifier unit comprises: an operational amplifier, wherein the positive input terminal of the operational amplifier is respectively connected to the output terminal of each of the magnetic modulation units, the output terminal of the operational amplifier is connected to the filtering unit, and the operational amplifier is used to average and amplify each of the initial detection signals and output a target detection signal; a first resistor, wherein a first end of the first resistor is connected to the negative input end of the operational amplifier, and a second end of the first resistor is grounded; A second resistor, wherein a first end of the second resistor is connected to the negative input end of the operational amplifier, and a second end of the second resistor is respectively connected to the output end of the operational amplifier and the filtering unit.

7. The magnetic modulation current sensor according to claim 5, characterized in that: The filtering unit comprises: A low-pass filter is connected to the operational amplifier unit and is used to filter out the signal of a preset frequency in the target detection signal and output a detection result, wherein the preset frequency is the frequency of the alternating current signal.

8. The magnetic modulation current sensor according to claim 1, characterized in that: The fixing member comprises a fixing ring, each of the biasing units is evenly arranged on the fixing ring, and the center of the fixing ring is located on the axis of the conductor to be tested.

9. The magnetic modulation current sensor according to claim 1, characterized in that: The magnetic modulation current sensor further comprises: a shell, the shell is connected to the fixing member, and the signal source and the signal processing circuit are located in the shell.

10. A current measurement system, characterized in that: The system comprises a conductor to be tested and a magnetic modulation current sensor as claimed in any one of claims 1 to 9.

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