Fluxgate current sensor and current measuring system

Abstract

The invention relates to a fluxgate current sensor and a current measurement system. The fluxgate current sensor comprises a detection assembly and an adjusting assembly, the detection assembly comprises a first magnetic core, a primary side coil, a secondary side coil and an induction unit, the primary side coil and the secondary side coil are wound on the two opposite sides of the first magnetic core in the first direction respectively, the primary side coil is used for being connected with a wire to be detected, and the secondary side coil is used for being connected with the wire to be detected. The induction unit is located on the side edge of the first magnetic core in the second direction, and the induction unit is used for generating an induction electric signal under the condition that the to-be-detected current transmitted by the to-be-detected wire flows through the primary side coil; wherein the first direction is different from the second direction, the adjusting assembly is connected with the induction unit and the secondary side coil, and the adjusting assembly is used for outputting excitation current to the secondary side coil according to the induction electric signal so as to offset magnetic flux generated by the current to be measured through the excitation current. The fluxgate current sensor has high accuracy.

Description

Technical Field

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

[0002] The fluxgate current sensor is a current measurement device with small temperature drift and time drift. It is widely used in medical equipment, aerospace, scientific instruments, DC power transmission and transformation, and other fields that require high current measurement accuracy and stability. The basic idea of ​​the fluxgate current sensor is to convert large current into small current that can be precisely measured based on electromagnetic induction, thereby realizing large current measurement.

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

[0004] Based on this, it is necessary to provide a fluxgate current sensor and current measurement system with higher accuracy to address the above technical issues.

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

[0006] A detection component, the detection component comprising a first magnetic core, a primary side coil, a secondary side coil and an induction unit, the primary side coil and the secondary side coil are respectively wound on two opposite sides of the first magnetic core in a first direction, the primary side coil is used to be connected to the wire to be measured, the induction unit is located on the side of the first magnetic core in a second direction, and the induction unit is used to generate an induced electrical signal when a current to be measured flows through the primary side coil and is transmitted by the wire to be measured; wherein the first direction is different from the second direction;

[0007] An adjusting component is connected to the induction unit and the secondary coil respectively, and is used to output an excitation current to the secondary coil according to the induced electrical signal, so as to offset the magnetic flux generated by the current to be measured through the excitation current.

[0008] In one of the embodiments, the induction unit includes at least one probe, which is located on the side of the first magnetic core in the second direction, and is used to generate an induced electrical signal when the current to be measured flows through the primary side coil and is transmitted by the wire to be measured, and when the ampere-turns of the primary side coil and the ampere-turns of the secondary side coil are unbalanced.

[0009] In one embodiment, the probe includes a first excitation winding and a second excitation winding connected to each other, wherein the first excitation winding and the second excitation winding are respectively located on two opposite sides of the first magnetic core in a third direction, wherein the first direction, the second direction and the third direction are perpendicular to each other, and the first excitation winding and the second excitation winding are used together to generate an induced electrical signal when the current to be measured flows through the primary side coil and is transmitted by the wire to be measured.

[0010] In one embodiment, the induced electrical signal includes a first induced electromotive force and a second induced electromotive force; the induction unit includes a first probe and a second probe, and the first probe and the second probe are both located on the side of the first magnetic core in the second direction and are arranged opposite to each other;

[0011] The first probe is used to generate a first induced electromotive force when the current to be measured flows through the wire to be measured and flows through the primary coil, and the ampere-turns of the primary coil and the ampere-turns of the secondary coil are unbalanced;

[0012] The second probe is used to generate a second induced electromotive force when the current to be measured flows through the wire to be measured and flows through the primary coil, and the ampere-turns of the primary coil and the ampere-turns of the secondary coil are unbalanced.

[0013] In one embodiment, the adjustment component includes:

[0014] A signal generating circuit, connected to the sensing unit, for generating a comparison signal according to the sensing electrical signal; wherein the comparison signal is opposite in phase to the sensing electrical signal;

[0015] A sampling control circuit, connected to the sensing unit, and configured to generate a control signal according to the sensing electrical signal and the comparison signal;

[0016] The magnetic flux compensation circuit is respectively connected to the signal generating circuit, the sampling control circuit and the secondary coil, and is used to output an excitation current to the secondary coil according to the control signal, so as to offset the magnetic flux generated by the current to be measured through the excitation current.

[0017] In one embodiment, the signal generating circuit comprises:

[0018] a first signal amplifying unit connected to the sensing unit and configured to amplify the sensing electrical signal to generate a first voltage signal, wherein the phase of the first voltage signal is the same as the phase of the current to be measured;

[0019] A signal modulation unit is connected to the first signal amplification unit and the sampling control circuit, and is used to perform phase conversion processing on the first voltage signal to generate a comparison signal, wherein the phase of the comparison signal is opposite to the phase of the current to be measured.

[0020] In one embodiment, the signal modulation unit includes:

[0021] a phase adjuster connected to the first signal amplifying unit, and configured to perform phase conversion processing on the first voltage signal to generate a square wave pulse signal, wherein the square wave pulse signal is opposite in phase to the current to be measured;

[0022] The triangular wave generator is connected to the phase adjuster and the sampling control circuit respectively, and is used for converting the square wave pulse signal into a triangular wave comparison signal.

[0023] In one embodiment, the sampling control circuit includes:

[0024] A sampling and conditioning unit, connected to the sensing unit, and used to convert the induced electrical signal into a DC voltage signal;

[0025] A correction unit, connected to the sampling and conditioning unit, for generating a voltage deviation suppression signal according to the DC voltage signal and a preset reference voltage;

[0026] A signal generating unit is connected to the signal generating circuit and the correction unit respectively, and is used to generate a control signal according to the voltage deviation suppression signal and the comparison signal.

[0027] In one embodiment, the magnetic flux compensation circuit includes:

[0028] Power supply unit;

[0029] A full-bridge unit is respectively connected to the power supply unit, the sampling control circuit and the secondary side coil. The full-bridge unit includes multiple switching tubes. The control signal is used to control the switching state of each switching tube in the full-bridge unit so that the power supply unit outputs an excitation current to the secondary side coil through the full-bridge unit.

[0030] In a second aspect, the present application provides a current measurement system, the system comprising: a conductor to be measured and a fluxgate current sensor as described in any one of the above embodiments.

[0031] The above-mentioned fluxgate current sensor and current measurement system include a detection component and an adjustment component. The detection component includes a first magnetic core, a primary side coil, a secondary side coil and an induction unit. The primary side coil and the secondary side coil are respectively wound on two opposite sides of the first magnetic core in a first direction. The induction unit is located on the side of the first magnetic core in a second direction. When the current to be measured flows through the primary side coil, the current to be measured will generate an alternating magnetic field around the first magnetic core. The magnetic field will pass through the induction unit to generate a magnetic flux, thereby causing the induction unit to generate an induced electrical signal based on the magnetic flux. The adjustment component can output an excitation current to the secondary side coil based on the induced electrical signal, so that the secondary side coil offsets the magnetic flux generated by the current to be measured through the excitation current, thereby eliminating the influence of the magnetic flux on the current detection result and improving the accuracy of current detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] FIG1 is a schematic diagram of the structure of a fluxgate current sensor in one embodiment;

[0034] FIG2 is a schematic diagram of the structure of a probe in one embodiment;

[0035] FIG3 is a schematic diagram of the structure of a fluxgate current sensor in another embodiment;

[0036] FIG4 is a schematic diagram of the structure of a fluxgate current sensor in another embodiment;

[0037] FIG5 is a schematic diagram of the structure of a fluxgate current sensor in another embodiment;

[0038] FIG6 is a schematic diagram of the structure of a fluxgate current sensor in yet another embodiment;

[0039] FIG7 is a schematic diagram of the structure of a fluxgate current sensor in another embodiment;

[0040] FIG8 is a schematic diagram of the structure of a fluxgate current sensor in yet another embodiment;

[0041] FIG. 9 is a schematic diagram of the structure of a fluxgate current sensor in yet another embodiment. DETAILED DESCRIPTION

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] It can be understood that the fluxgate current sensor in the related art only has a magnetic core, a primary winding and a secondary winding. When the current to be measured flows through the primary winding, the current to be measured will generate an alternating magnetic field on the magnetic core. The alternating magnetic field passes through the secondary winding, generating an induced current on the secondary winding. The magnitude of the current to be measured on the primary winding can be calculated by detecting the induced current on the secondary winding and combining the number of turns of the primary winding and the secondary winding. However, the fluxgate current sensor in the related art has a certain error, which is caused by the excitation current of the magnetic core. The larger the excitation current, the greater the error of the fluxgate current sensor detection result.

[0049] Based on this, please refer to FIG. 1 , the present application provides a fluxgate current sensor, which includes a detection component 1 and a regulation component 2 .

[0050] The detection component 1 includes a first magnetic core 11, a primary coil 12, a secondary coil 13 and an induction unit 14. The primary coil 12 and the secondary coil 13 are respectively wound on two opposite sides of the first magnetic core 11 in a first direction. The primary coil 12 is used to connect to the wire to be tested. The induction unit 14 is located on the side of the first magnetic core 11 in a second direction. The induction unit 14 is used to generate an induced electrical signal when the current to be tested flows through the wire to be tested on the primary coil 11, wherein the first direction is different from the second direction. The adjustment component 2 is respectively connected to the induction unit 14 and the secondary coil 13. The adjustment component 2 is used to output an excitation current to the secondary coil 13 according to the induced electrical signal, so as to offset the magnetic flux generated by the current to be tested through the excitation current.

[0051] In the present application, an induction unit 14 is added to the first magnetic core 11 of the traditional current sensor. When the current to be measured flows through the primary coil 12, and the ampere-turns of the primary coil 12 and the secondary coil 13 are not actually balanced, an alternating magnetic field will be generated on the first magnetic core. The induction unit 14 is installed on the side of the first magnetic core 11 in the second direction, and can detect the alternating magnetic field on the first magnetic core. The first direction is the X-axis direction shown in Figure 1, and the second direction is the Y-axis direction shown in Figure 1.

[0052] The alternating magnetic field passes through the induction unit 14 to generate magnetic flux. The induction unit 14 generates an induced electrical signal based on the magnetic flux and sends the induced electrical signal to the adjustment component 2. The adjustment component 2 can output an excitation current with a phase opposite to that of the current to be measured to the secondary side coil 13 according to the induced electrical signal. Since the excitation current is in opposite phase to the current to be measured, the magnetomotive force generated by the excitation current and the current to be measured is naturally opposite. Ultimately, the magnetomotive force in the first magnetic core is 0, and the magnetic flux is also 0. The ampere-turns of the primary side coil 12 and the secondary side coil 13 are actually balanced, and the accuracy of the detection result of the fluxgate current sensor is improved.

[0053] The above-mentioned fluxgate current sensor includes a detection component and an adjustment component. The detection component includes a first magnetic core, a primary side coil, a secondary side coil and an induction unit. The primary side coil and the secondary side coil are respectively wound on two opposite sides of the first magnetic core in a first direction. The induction unit is located on the side of the first magnetic core in a second direction. When the current to be measured flows through the primary side coil, the current to be measured will generate an alternating magnetic field around the first magnetic core. The magnetic field will pass through the induction unit to generate a magnetic flux, thereby causing the induction unit to generate an induced electrical signal based on the magnetic flux. The adjustment component can output an excitation current to the secondary side coil based on the induced electrical signal, so that the secondary side coil can offset the magnetic flux generated by the current to be measured through the excitation current, thereby eliminating the influence of the magnetic flux on the current detection result and improving the accuracy of current detection.

[0054] In one embodiment, please continue to refer to Figure 1, the induction unit 14 includes at least one probe 140, which is located on the side of the first magnetic core 11 in the second direction, and is used to generate an induced electrical signal when the current to be measured flows through the measured wire on the primary side coil 12 and the ampere-turns of the primary side coil 12 and the ampere-turns of the secondary side coil 13 are unbalanced.

[0055] In one example, the induction unit 14 may include at least one probe 140, and the probe 140 may be a fluxgate sensor probe. Referring to FIG2 , the probe 140 includes a first excitation winding 1401 and a second excitation winding 1402, as well as a second magnetic core 1403 and a third magnetic core 1404, which are connected to each other. The first excitation winding and the second excitation winding are respectively wound on the second magnetic core 1403 and the third magnetic core 1404, and are located on two opposite sides of the first magnetic core 11 in a third direction, the third direction being the Z-axis direction shown in FIG1 , the first direction, the second direction and the third direction being perpendicular to each other, and the first excitation winding 1401 and the second excitation winding 1402 are used together to generate an induced electrical signal when the current to be measured flows through the wire to be measured on the primary side coil 12 and is transmitted.

[0056] When the ampere-turns of the primary coil 12 and the secondary coil 13 are not actually equal, an alternating magnetic field will be generated on the first magnetic core 11, and the magnetic field will pass through the first excitation winding 1401 and the second excitation winding 1402 embedded in the magnetic core 11, so that the probe 140 will generate an induced electrical signal. When the ampere-turns of the primary coil 12 and the secondary coil 13 are actually equal, the magnetomotive force in the first magnetic core is 0, and the magnitude of the induced electrical signal generated by the probe 140 is also 0. Therefore, in the present application, the induced electrical signal is generated by the probe 140, and the current on the secondary coil 13 is adjusted based on the induced electrical signal, which can truly reflect whether the ampere-turns of the primary coil 12 and the secondary coil 13 are balanced.

[0057] In one embodiment, the induced electrical signal includes a first induced electromotive force and a second induced electromotive force. Referring to FIG3 , the induction unit 14 includes a first probe 141 and a second probe 142 , both of which are located on the side of the first magnetic core 11 in the second direction and are arranged opposite to each other, and both of the first probe 141 and the second probe 142 are connected to the adjustment component 2 .

[0058] The first probe 141 is used to generate a first induced electromotive force when the current to be measured flows through the wire to be measured on the primary coil 12 and the ampere-turns of the primary coil 12 are unbalanced with the ampere-turns of the secondary coil 13. The second probe 142 is used to generate a second induced electromotive force when the current to be measured flows through the wire to be measured on the primary coil 12 and the ampere-turns of the primary coil 12 are unbalanced with the ampere-turns of the secondary coil 13.

[0059] In this embodiment, by respectively arranging the first probe 141 and the second probe 142 on the two opposite sides of the first magnetic core 11 in the second direction, the accuracy of the induced electrical signal received by the adjustment component 2 can be ensured. Exemplarily, when there is no interference around the first magnetic core 11, the first probe 141 generates a first induced electromotive force E, and the second probe 142 generates a second induced electromotive force -E, and the adjustment component performs a subtraction process on the received first induced electromotive force E and the second induced electromotive force -E to obtain a target induced electromotive force 2E, and outputs an excitation current to the secondary side coil 13 according to the target induced electromotive force 2E; when there is interference around the first magnetic core 11, the first probe 141 generates a first induced electromotive force E+a, and the second probe 142 generates a second induced electromotive force -E+a, and the adjustment component performs a subtraction process on the received first induced electromotive force E+a and the second induced electromotive force -E+a to obtain a target induced electromotive force 2E, and outputs an excitation current to the secondary side coil 13 according to the target induced electromotive force 2E. It can be seen that by symmetrically arranging two probes on the first magnetic core 11 , it is possible to prevent the adjustment component 2 from being interfered by the outside world, thereby ensuring the accuracy of the excitation current output by the adjustment component 2 .

[0060] In one embodiment, referring to FIG. 4 , the regulating component 2 includes a signal generating circuit 21 , a sampling control circuit 22 and a magnetic flux compensation circuit 23 .

[0061] The signal generating circuit 21 is connected to the sensing unit 14, and is used to generate a comparison signal according to the induced electrical signal, wherein the comparison signal is opposite in phase to the induced electrical signal. The sampling control circuit 22 is connected to the sensing unit 14, and is used to generate a control signal according to the induced electrical signal and the comparison signal. The magnetic flux compensation circuit 23 is respectively connected to the signal generating circuit 21, the sampling control circuit 22, and the secondary coil 13, and is used to output an excitation current to the secondary coil 13 according to the control signal, so as to offset the magnetic flux generated by the current to be measured through the excitation current.

[0062] The signal generating circuit 21 can receive the induced electrical signal generated by the induction component. Since the induced electrical signal is generated based on the magnetic field generated by the current to be measured, the phase of the induced electrical signal is the same as the phase of the current to be measured. Since the magnetic flux on the first magnetic core 11 needs to be controlled to be 0, the magnetic flux generated by the excitation current on the secondary side coil needs to be able to offset the magnetic flux generated by the current to be measured on the primary side coil. Therefore, the phase of the excitation current on the secondary side coil needs to be controlled to be always opposite to the phase of the current to be measured on the primary side coil. Therefore, in the present application, a signal generating circuit 21 is set to generate a comparison signal with a phase opposite to that of the current to be measured in real time according to the induced electrical signal.

[0063] At the same time, since it is necessary to control the magnetic flux on the first magnetic core 11 to be 0, that is, it is necessary to control the size of the induced electrical signal generated by the induction unit 14 to be 0, a sampling control circuit 22 is set in the present application to detect the size of the induced electrical signal in real time, and output a control signal to the magnetic flux compensation circuit 23 based on the induced electrical signal and the comparison signal, so that the magnetic flux compensation circuit 23 can output an excitation current to the secondary side coil 13 in real time, which is opposite to the phase of the current to be measured and can make the magnetic flux on the first magnetic core 11 0.

[0064] In one embodiment, referring to FIG. 5 , the signal generating circuit 21 includes a first signal amplifying unit 211 and a signal modulating unit 212 .

[0065] The first signal amplifying unit 211 is connected to the sensing unit 14, and is used to amplify the induced electrical signal to generate a first voltage signal, wherein the phase of the first voltage signal is the same as the phase of the current to be measured. The signal modulating unit 212 is connected to the first signal amplifying unit 211 and the sampling control circuit 22, and is used to perform phase conversion processing on the first voltage signal to generate a comparison signal, wherein the phase of the comparison signal is opposite to the phase of the current to be measured.

[0066] It can be understood that after the first signal amplifying unit 211 receives the induced electrical signal, it first needs to amplify the induced electrical signal to convert the induced electrical signal into a detectable alternating first voltage signal. Afterwards, the first signal amplifying unit 211 sends the first voltage signal to the signal modulating unit 212, so that the signal modulating unit 212 performs a phase shift on the first voltage signal and generates a comparison signal, so that the phase of the excitation current output by the rear magnetic flux compensation circuit 23 is always opposite to the phase of the current to be measured.

[0067] In one embodiment, referring to FIG. 6 , the signal modulation unit 212 includes a phase adjuster 2121 and a triangle wave generator 2122 .

[0068] The phase adjuster 2121 is connected to the first signal amplifying unit 211, and is used to perform phase conversion processing on the first voltage signal to generate a square wave pulse signal, wherein the square wave pulse signal is opposite in phase to the current to be measured. The triangle wave generator 2122 is connected to the phase adjuster 2121 and the sampling control circuit 22, respectively, and is used to convert the square wave pulse signal into a triangle wave comparison signal.

[0069] In this embodiment, the control signal output by the sampling control circuit 22 to the flux compensation circuit 23 is a PWM signal, and the PWM signal is generated by modulating a triangular wave and a reference electrical signal. Therefore, in this application, the phase of the first voltage signal is first detected by the phase adjuster 2121, and a square wave pulse signal with a phase opposite to that of the first voltage signal is output according to the first voltage signal, and then the triangular wave generator 2122 is triggered by the phase adjuster 2121 to convert the square wave pulse signal into a triangular wave comparison signal.

[0070] In one embodiment, referring to FIG. 7 , the sampling control circuit 22 includes a sampling conditioning unit 221 , a correction unit 222 and a signal generating unit 223 .

[0071] The sampling and conditioning unit 221 is connected to the sensing unit 14, and is used to convert the induced electrical signal into a DC voltage signal. The correction unit 222 is connected to the sampling and conditioning unit 221, and is used to generate a voltage deviation suppression signal according to the DC voltage signal and a preset reference voltage. The signal generating unit 223 is respectively connected to the signal generating circuit 21 and the correction unit 222, and is used to generate a control signal according to the voltage deviation suppression signal and the comparison signal.

[0072] It can be understood that the sampling and conditioning unit 221 can amplify the received induced electrical signal, convert the AC induced electrical signal into a DC voltage signal, clamp the DC voltage signal within a certain range, and then output the DC voltage signal to the correction unit 222. In one example, the correction unit 222 can be a PI controller, and the correction unit 222 can generate a voltage deviation suppression signal based on the received DC voltage signal and a preset reference voltage. The preset reference voltage can be 0. The signal generating unit 223 generates a control signal based on the voltage deviation suppression signal and the comparison signal to control the flux compensation circuit, so as to adjust the excitation current on the secondary coil so that the magnetic flux in the first magnetic core dynamically approaches 0, thereby eliminating the interference of the magnetic flux on the measurement result.

[0073] In one example, referring to FIG. 8 , the sampling and conditioning unit 221 may include a second signal amplifying subunit and a conditioning subunit 2211, wherein the second signal amplifying subunit may reuse the first signal amplifying unit 211 in the signal generating circuit 21, and the conditioning subunit 2211 is connected to the first signal amplifying unit 211 to convert the first voltage signal into a DC voltage signal and clamp the DC voltage signal within a certain range.

[0074] The correction unit 222 may include a subtractor 2221, a proportional subunit 2222, an integral subunit 2223 and an adder 2224. The subtractor 2221 is connected to the conditioning subunit 2211, and is used to subtract the DC voltage signal from a preset reference voltage to output a voltage difference signal. The proportional subunit 2222 is respectively connected to the subtractor 2221 and the adder 2224. The integral subunit 2223 is respectively connected to the subtractor 2221 and the adder 2224. The proportional subunit 2222 is used to output a proportional signal according to the voltage difference signal so that the induced electrical signal changes in a direction of reducing the deviation. The integral subunit 2223 is used to output an integral signal according to the voltage difference signal to further reduce the voltage difference signal. Then the adder adds the proportional signal and the proportional signal to output a voltage deviation suppression signal.

[0075] The signal generating unit 223 may be a comparator 2231 , and the comparator 2231 is configured to output a control signal according to a comparison signal between the voltage deviation suppression signal and the triangular wave.

[0076] In one embodiment, referring to FIG. 9 , the magnetic flux compensation circuit 23 includes a power supply unit 231 , a full-bridge unit 232 , a protection unit 233 and a capacitor C1 .

[0077] The full-bridge unit 232 is respectively connected to the power supply unit 231, the sampling control circuit 22 and the secondary coil 13. The full-bridge unit 232 includes a plurality of switch tubes. The control signal is used to control the switch state of each switch tube in the full-bridge unit so that the power supply unit outputs an excitation current to the secondary coil through the full-bridge unit. The protection unit 233 is respectively connected to the power supply unit 231 and the full-bridge unit 232.

[0078] In this embodiment, the full-bridge unit 232 may include a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first diode Q1, a second diode D2, a third diode D3, and a fourth diode D4. A first end of the first switch tube Q1 and a first end of the second switch tube Q2 are respectively connected to the positive electrode of the power supply unit, a second end of the first switch tube Q1 is respectively connected to a first end of the fourth switch tube Q4 and a first end of the secondary side coil, a second end of the second switch tube Q2 is respectively connected to a first end of the third switch tube Q3 and a second end of the secondary side coil, and a second end of the third switch tube Q3 and a second end of the fourth switch tube Q4 are respectively connected to the negative electrode of the power supply unit.

[0079] The full-bridge unit 232 uses a two-by-two alternating conduction method to control the generation of an alternating excitation current. When the first switch tube Q1 and the third switch tube Q3 are turned on, the current flows through the first switch tube Q1, flows into the secondary coil, and flows out of the full-bridge unit from the third switch tube Q3; when the first switch tube Q1 and the third switch tube Q3 are turned off, due to the freewheeling effect of the secondary coil inductance, the current flows through the diode D3, flows into the secondary coil, and flows out of the full-bridge unit from the diode D1; when the second switch tube Q2 and the fourth switch tube Q4 are turned on, the current flows through the second switch tube Q2, flows into the secondary coil, and flows out of the full-bridge unit from the fourth switch tube Q4; when the second switch tube Q2 and the fourth switch tube Q4 are turned off, due to the freewheeling effect of the secondary coil inductance, the current flows through the fourth diode D4, flows into the secondary coil, and flows out of the full-bridge unit from the second diode D2.

[0080] Under the control of the control signal, the magnetic flux compensation circuit 23 always outputs an excitation current with a phase opposite to that of the current to be measured, so that the magnetic flux generated by the excitation current and the magnetic flux generated by the current to be measured cancel each other out, eliminating the influence of the excitation current. When the magnetic flux generated by the excitation current and the magnetic flux generated by the current to be measured cancel each other out, the ampere-turns of the primary coil and the ampere-turns of the secondary coil are actually balanced, so the magnitude of the current to be measured can be calculated based on the turns of the primary coil, the turns of the secondary coil and the current value of the secondary coil.

[0081] In one embodiment, the present application provides a current measurement system, which includes: a conductor to be measured and a fluxgate current sensor according to any one of the above embodiments.

[0082] 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.

[0083] 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.

[0084] 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 fluxgate current sensor, characterized in that: The fluxgate current sensor comprises: A detection component, the detection component comprising a first magnetic core, a primary side coil, a secondary side coil and an induction unit, the primary side coil and the secondary side coil are respectively wound on two opposite sides of the first magnetic core in a first direction, the primary side coil is used to be connected to the wire to be measured, the induction unit is located on the side of the first magnetic core in a second direction, and the induction unit is used to generate an induced electrical signal when a current to be measured flows through the primary side coil and is transmitted by the wire to be measured; wherein the first direction is different from the second direction; An adjusting component is connected to the induction unit and the secondary coil respectively, and is used to output an excitation current to the secondary coil according to the induced electrical signal, so as to offset the magnetic flux generated by the current to be measured through the excitation current.

2. The fluxgate current sensor according to claim 1, characterized in that: The induction unit includes at least one probe, which is located on the side of the first magnetic core in the second direction, and is used to generate an induced electrical signal when the current to be measured flows through the primary side coil and is transmitted by the wire to be measured, and when the ampere-turns of the primary side coil and the ampere-turns of the secondary side coil are unbalanced.

3. The fluxgate current sensor according to claim 2, characterized in that: The probe includes a first excitation winding and a second excitation winding connected to each other, wherein the first excitation winding and the second excitation winding are respectively located on two opposite sides of the first magnetic core in a third direction, wherein the first direction, the second direction and the third direction are perpendicular to each other, and the first excitation winding and the second excitation winding are used together to generate an induced electrical signal when the current to be measured flows through the primary side coil and is transmitted by the wire to be measured.

4. The fluxgate current sensor according to claim 1, characterized in that: The induced electrical signal includes a first induced electromotive force and a second induced electromotive force; the induction unit includes a first probe and a second probe, the first probe and the second probe are both located on the side of the first magnetic core in the second direction and are arranged opposite to each other; The first probe is used to generate a first induced electromotive force when the current to be measured flows through the wire to be measured and flows through the primary coil, and the ampere-turns of the primary coil and the ampere-turns of the secondary coil are unbalanced; The second probe is used to generate a second induced electromotive force when the current to be measured flows through the wire to be measured and flows through the primary coil, and the ampere-turns of the primary coil and the ampere-turns of the secondary coil are unbalanced.

5. The fluxgate current sensor according to claim 1, characterized in that: The adjustment component comprises: A signal generating circuit, connected to the sensing unit, for generating a comparison signal according to the sensing electrical signal; wherein the comparison signal is opposite in phase to the sensing electrical signal; A sampling control circuit, connected to the sensing unit, and configured to generate a control signal according to the sensing electrical signal and the comparison signal; The magnetic flux compensation circuit is respectively connected to the signal generating circuit, the sampling control circuit and the secondary coil, and is used to output an excitation current to the secondary coil according to the control signal, so as to offset the magnetic flux generated by the current to be measured through the excitation current.

6. The fluxgate current sensor according to claim 5, characterized in that: The signal generating circuit comprises: a first signal amplifying unit connected to the sensing unit and configured to amplify the sensing electrical signal to generate a first voltage signal, wherein the phase of the first voltage signal is the same as the phase of the current to be measured; A signal modulation unit is connected to the first signal amplification unit and the sampling control circuit, and is used to perform phase conversion processing on the first voltage signal to generate a comparison signal, wherein the phase of the comparison signal is opposite to the phase of the current to be measured.

7. The fluxgate current sensor according to claim 6, characterized in that: The signal modulation unit comprises: a phase adjuster connected to the first signal amplifying unit, and configured to perform phase conversion processing on the first voltage signal to generate a square wave pulse signal, wherein the square wave pulse signal is opposite in phase to the current to be measured; The triangular wave generator is connected to the phase adjuster and the sampling control circuit respectively, and is used for converting the square wave pulse signal into a triangular wave comparison signal.

8. The fluxgate current sensor according to claim 5, characterized in that: The sampling control circuit comprises: A sampling and conditioning unit, connected to the sensing unit, and used to convert the induced electrical signal into a DC voltage signal; A correction unit, connected to the sampling and conditioning unit, for generating a voltage deviation suppression signal according to the DC voltage signal and a preset reference voltage; A signal generating unit is connected to the signal generating circuit and the correction unit respectively, and is used to generate a control signal according to the voltage deviation suppression signal and the comparison signal.

9. The fluxgate current sensor according to claim 5, characterized in that: The magnetic flux compensation circuit comprises: Power supply unit; A full-bridge unit is respectively connected to the power supply unit, the sampling control circuit and the secondary side coil. The full-bridge unit includes multiple switching tubes. The control signal is used to control the switching state of each switching tube in the full-bridge unit so that the power supply unit outputs an excitation current to the secondary side coil through the full-bridge unit.

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

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