Magnetic modulation current sensor

Abstract

The invention relates to a magnetic modulation current sensor which comprises a first half magnetic ring and a second half magnetic ring, and the first half magnetic ring and the second half magnetic ring form a ring-like structure with two air gaps. A tested coil passes through a hole formed by the ring-like structure. The 2N magnetic modulation sensing chips are arranged between one air gap and a tested coil, and the other 2N magnetic modulation sensing chips are arranged between the other air gap and the tested coil; the magnetic shunting structure is arranged at any air gap or is respectively arranged at one air gap, and the magnetic shunting structure is connected with the input end of each magnetic modulation sensing chip; the signal amplification circuit is connected with the output end of each magnetic modulation sensing chip and is used for outputting a first voltage signal; and the sampling circuit is used for outputting a digital signal according to the first voltage signal, and the digital signal is used for representing the size of the first voltage signal. Compared with a traditional sensor, the magnetic modulation current sensor provided by the invention can further improve the measuring range of the magnetic modulation current sensor.

Description

Technical Field

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

[0002] The magnetic modulation current sensor is a high-precision, high-stability current measurement device that is widely used in industries such as automotive manufacturing, smart home, and environmental monitoring.

[0003] However, as the demand for the use of magnetic modulation current sensors continues to increase, there are higher requirements for the range of magnetic modulation current sensors. Specifically, the range needs to be larger and larger. Therefore, in order to meet higher requirements, it is necessary to improve the traditional magnetic modulation current sensor.

[0004] How to improve the traditional magnetic modulation current sensor to increase the measuring range is still an urgent problem to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide a magnetic modulation current sensor that can improve the measuring range.

[0006] In a first aspect, a magnetic modulation current sensor is provided, comprising:

[0007] A first half magnetic ring and a second half magnetic ring are arranged opposite to each other, wherein the first half magnetic ring and the second half magnetic ring form a ring-like structure with two air gaps; and the measured coil passes through a hole formed by the ring-like structure;

[0008] 4N magnetic modulation sensor chips, wherein 2N magnetic modulation sensor chips are arranged between one air gap and the coil to be measured, and another 2N magnetic modulation sensor chips are arranged between another air gap and the coil to be measured; N is a natural number greater than zero;

[0009] A magnetic shunt structure, disposed at any of the air gaps, the magnetic shunt structure being connected to an input end of each of the magnetic modulation sensor chips;

[0010] a signal amplifying circuit connected to the output end of each of the magnetic modulation sensor chips, and configured to amplify the electrical signals output by the 4N magnetic modulation sensor chips and output a first voltage signal;

[0011] The sampling circuit is connected to the output end of the signal amplifying circuit and is used to output a digital signal according to the first voltage signal, wherein the digital signal is used to characterize the magnitude of the first voltage signal.

[0012] In one embodiment, the sampling circuit includes:

[0013] a sampling unit, connected to the output end of the signal amplifying circuit, and used for acquiring the first voltage signal;

[0014] a level conversion circuit connected to the output end of the sampling unit, and configured to convert a negative voltage signal in the first voltage signal into a positive voltage signal and then output a second voltage signal;

[0015] The digital sampling filter circuit is connected to the output end of the level conversion circuit, and is used for filtering the second voltage signal, converting the filtered second voltage signal into the digital signal and outputting it.

[0016] In one embodiment, the sampling unit is further used to output a control voltage according to the first voltage signal or an externally input preset voltage signal;

[0017] The magnetic modulation current sensor further comprises:

[0018] A feedback coil is arranged on the first half magnetic ring and / or arranged on the second half magnetic ring;

[0019] The feedback coil is connected to the output end of the sampling unit;

[0020] The feedback coil is used to generate a feedback current under the action of the control voltage, and the feedback current is used to keep the first half magnetic ring and the second half magnetic ring at zero magnetic flux.

[0021] In one embodiment, the sampling unit comprises:

[0022] A transmission unit, configured to receive the first voltage signal;

[0023] A feedback control unit is connected to the output end of the transmission unit and is also connected to the feedback coil. The feedback control unit is used to control the magnitude of the feedback current on the feedback coil according to the first voltage signal.

[0024] In one embodiment, the signal amplification circuit includes:

[0025] 4N first-level signal amplification units, wherein different first-level signal amplification units are connected to different magnetic modulation sensor chips, and the first-level signal amplification units are used to perform first-level amplification processing on the electrical signal output by the connected magnetic modulation sensor chip; the 4N first-level signal amplification units output a third voltage signal;

[0026] The power amplifier circuit is connected to the output ends of the 4N first-level signal amplification units, and is used to output the first voltage signal after performing a second-level amplification process on the third voltage signal.

[0027] In one embodiment, the power amplifier circuit includes:

[0028] A dual-power amplifier, wherein a first terminal of the dual-power amplifier receives the third voltage signal, and a second terminal of the dual-power amplifier is connected to an output terminal of the dual-power amplifier;

[0029] A first filter capacitor group is connected to a first power input terminal of the dual power amplifier;

[0030] The second filter capacitor group is connected to the second power input terminal of the dual power amplifier.

[0031] In one embodiment, the first filter capacitor group includes:

[0032] A plurality of first capacitors, wherein first ends of the first capacitors are connected to the first power supply and the first power supply input terminal, and second ends of the first capacitors are grounded;

[0033] The first end of the first capacitor is also connected to the first end of the adjacent first capacitor, and the second end of the first capacitor is also connected to the second end of the adjacent first capacitor.

[0034] In one embodiment, the second filter capacitor group includes:

[0035] A plurality of second capacitors, wherein first ends of the second capacitors are connected to the second power supply and the second power supply input terminal, and second ends of the second capacitors are grounded;

[0036] The first end of the second capacitor is further connected to the first end of the adjacent second capacitor, and the second end of the second capacitor is further connected to the second end of the adjacent second capacitor.

[0037] In one embodiment, the two air gaps are symmetrically arranged along a first direction, and the 2N magnetic modulation sensor chips on one side are symmetrically arranged along a second direction;

[0038] The first direction and the second direction are perpendicular to each other.

[0039] In a second aspect, a magnetic field monitoring device is provided, comprising a monitor and the magnetic modulation current sensor as described in the first aspect;

[0040] The monitor is connected to the output end of the sampling circuit in the magnetic modulation current sensor, and is used to display the magnetic field changes of the first half magnetic ring and the second half magnetic ring in the magnetic modulation current sensor according to multiple digital signals output by the sampling circuit over a period of time.

[0041] In the above-mentioned magnetic modulation current sensor, when the measured coil is passed with current, this type of annular structure gathers the current in this type of annular structure. If the current on the measured coil is large, the leakage magnetic intensity at the air gap is generally strong. Therefore, the magnetic shunt structure is used to perform magnetic shunt processing on the leakage magnetic generated at the air gap, which can greatly reduce the magnetic field detected by the magnetic modulation sensor chips placed on the left and right sides of the magnetic flux guide, realize the function of large current detection, and expand the measurement range of the magnetic modulation current sensor. In addition, by increasing the number of magnetic modulation sensor chips, the measurement range of the magnetic modulation current sensor can also be expanded to realize dual-range measurement (low-range measurement and high-range measurement). 4N magnetic modulation sensor chips are symmetrically distributed in pairs, and can be used for different measurement tasks and measurement scenario requirements respectively. This layout helps to realize multi-dimensional magnetic field detection and improve the accuracy and reliability of measurement. Through experimental verification, the magnetic modulation current sensor designed in this embodiment has the advantages of wide range, high resolution and high linearity, and has broad application scenarios in new energy vehicles, clean energy industry and other electrical related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 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.

[0043] FIG1 is a magnetic modulation current sensor according to an embodiment;

[0044] FIG2 is a diagram showing the structure of the magnetic shunt structure in FIG1 ;

[0045] FIG3 is a structure of the sampling circuit in FIG1 ;

[0046] FIG4 is a magnetic modulation current sensor according to another embodiment;

[0047] FIG5 is a structure of the signal amplifying circuit in FIG1 ;

[0048] FIG. 6 shows the structure of the power amplifier circuit in FIG. 5 .

[0049] Description of reference numerals:

[0050] 10. Magnetic modulation current sensor; 11. First half magnetic ring; 12. Second half magnetic ring; 13. Magnetic modulation sensor chip; 14. Magnetic shunt structure; 15. Signal amplification circuit; 16. Sampling circuit; 17. Feedback coil; 20. Measured coil; 110. Air gap; 141. Fixed frame; 142. Magnetic flux guide; 151. Primary signal amplification unit; 152. Power amplification circuit; 153. Dual power amplifier; 154. First filter capacitor group; 155. Second filter capacitor group; 156. First capacitor; 157. Second capacitor; 161. Sampling unit; 162. Level conversion circuit; 163. Digital sampling filter circuit; 164. Transmission unit; 165. Feedback control unit. DETAILED DESCRIPTION

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] When used herein, the singular forms "a", "an", and "the" may also include the 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.

[0057] As shown in FIG1 , an embodiment provides a magnetic modulation current sensor 10, which includes: a first half magnetic ring 11, a second half magnetic ring 12, 4N magnetic modulation sensor chips 13, a signal amplification circuit 15 and a sampling circuit 16. N is a natural number greater than zero. For example, when N is equal to 1, the magnetic modulation current sensor 10 includes 4 magnetic modulation sensor chips 13. The first half magnetic ring 11 and the second half magnetic ring 12 are arranged relative to each other. Specifically, the first half magnetic ring 11 and the second half magnetic ring 12 are arranged relative to each other along a first direction. The shape, size and material of the first half magnetic ring 11 and the second half magnetic ring 12 can be consistent. The first half magnetic ring 11 and the second half magnetic ring 12 form a ring-like structure with two air gaps 110. The sizes of the two air gaps 110 can be consistent. The measured coil 20 passes through the hole formed by the ring-like structure.

[0058] This type of annular structure is a single magnetic ring structure, which simplifies the structure of the magnetic ring, reduces costs and improves reliability. This type of functional structure helps to reduce magnetic field leakage and magnetic field interference, and improves the accuracy of magnetic field measurement. Preferably, according to the factors such as coercive force, magnetic permeability, saturation magnetic induction intensity, resistivity, etc., the selection is sorted in order, and finally an iron-based nanocrystalline material with excellent comprehensive performance is selected as the magnetic ring material of the first half magnetic ring 11 and the second half magnetic ring 12. Iron-based nanocrystals are mainly iron elements, with a small amount of niobium, copper, silicon, boron and other elements added. On the basis of amorphous alloys, a soft magnetic alloy material with a nanocrystalline structure is obtained through processes such as heat treatment. The heat treatment process is simple and has more excellent performance.

[0059] 4N magnetic modulation sensor chips 13, of which 2N magnetic modulation sensor chips 13 are arranged between one air gap 110 and the coil 20 to be measured, and the other 2N magnetic modulation sensor chips 13 are arranged between another air gap 110 and the coil 20 to be measured. The magnetic modulation sensor chip 13 outputs an electrical signal under the action of a magnetic field. The stronger the magnetic field, the greater the voltage value of the output electrical signal, and the weaker the magnetic field, the smaller the voltage value of the output electrical signal. The magnetic modulation sensor chip 13 is generated from a layered magnetic film structure. When an external magnetic field acts on this structure, the resistivity of the magnetic material will change greatly. Therefore, the magnetic modulation sensor chip 13 is arranged so that the magnetic modulation current sensor 10 can detect the magnetic field change with high sensitivity, and then measure the current.

[0060] When the use scenario requires that the range of the magnetic modulation current sensor 10 is small, only some of the 4N magnetic modulation sensor chips 13 can be used, and the magnetic field can be allocated to only these magnetic modulation sensor chips 13. When the use scenario requires that the range of the magnetic modulation current sensor 10 is large, the magnetic field can be allocated to the 4N magnetic modulation sensor chips 13. And by setting 4N magnetic modulation sensor chips 13, even if one or several magnetic modulation sensor chips 13 have problems, the other magnetic modulation sensor chips 13 can still work normally, ensuring the stability and reliability of the magnetic modulation current sensor 10.

[0061] Preferably, the two air gaps 110 are symmetrically arranged along the first direction, and the 2N magnetic modulation sensor chips 13 on one side are symmetrically arranged along the second direction. The first direction and the second direction are perpendicular to each other. The 4N magnetic modulation sensor chips 13 on both sides are symmetrically arranged along the first direction. When affected by an external non-uniform magnetic field, the symmetrically arranged magnetic modulation sensor chips 13 can offset each other's magnetic field changes, thereby greatly reducing the influence of the external magnetic field on the magnetic modulation current sensor 10 and improving the anti-interference ability of the magnetic modulation current sensor 10. In addition, this symmetrical layout helps to achieve multi-dimensional magnetic field detection and improve the accuracy of measurement.

[0062] The magnetic shunt structure 14 is disposed at any of the air gaps 110 and connected to the input end of each of the magnetic modulation sensor chips 13 .

[0063] Please refer to FIG. 2 , the magnetic shunt structure 14 may include two fixing frames 141 made of non-magnetic material, and also include a magnetic flux guide 142. The fixing frame 141 is connected to the inner wall of the opening of the air gap 110. The magnetic flux guide 142 is in the shape of a long quadrangular prism and is arranged between the two fixing frames. The magnetic flux guide 142 and the fixing frame 141 form an "I"-shaped structure. The magnetic shunt structure 14 can be used to distribute the magnetic field to the magnetic modulation sensor chip 13 to achieve low-range measurement and high-range measurement.

[0064] When the measured coil 20 is passed with current, the annular structure gathers the current in the annular structure and generates leakage magnetic field at the air gap 110, and the direction of the generated leakage magnetic field is perpendicular to the two opposite surfaces of the air gap 110. If the current on the measured coil 20 is large, the leakage magnetic field intensity at the air gap 110 is generally strong. Therefore, if the magnetic modulation sensor chip 13 is directly placed at the air gap 110, the magnetic modulation sensor chip 13 will be saturated quickly, and it is difficult to achieve the measurement of a large range of current. Therefore, the magnetic shunt structure 14 is used to perform magnetic shunt processing on the leakage magnetic field generated at the air gap 110, so that the magnetic field detected by the magnetic modulation sensor chip 13 placed on the left and right sides of the magnetic flux guide can be greatly reduced, and the function of large current detection can be achieved.

[0065] The signal amplification circuit 15 is connected to the output end of each magnetic modulation sensor chip 13, and is used to amplify the electrical signals output by the 4N magnetic modulation sensor chips 13 and output a first voltage signal. The electrical signals output by the 4N magnetic modulation sensor chips 13 are relatively weak. The main purpose of using the signal amplification circuit 15 is to enhance the weak electrical signals output by the magnetic modulation sensor chips 13 to a certain amplitude to facilitate the processing of subsequent circuits. When an alternating current is passed through the coil under test, the magnetic core of the magnetic modulation chip 13 is periodically oversaturated under the action of the alternating magnetic field, and the magnetic induction intensity changes periodically. This change is converted into an electrical signal output by the magnetic modulation chip, and the output electrical signal contains information related to the measured magnetic field or current. By processing the electrical signal output by the magnetic modulation chip through the signal amplification circuit, a voltage signal proportional to the magnitude of the measured magnetic field or current can be extracted.

[0066] The sampling circuit 16 is connected to the output end of the signal amplifying circuit 15, and is used to output a digital signal according to the first voltage signal, and the digital signal is used to characterize the magnitude of the first voltage signal. The output end of the sampling circuit 16 can be connected to a display device to display the magnitude of the first voltage signal in real time, so as to facilitate the observation of the magnetic field changes on the measured coil 20.

[0067] The sampling circuit 16 may include a sampling unit 161 , an analog-to-digital converter, etc., which is not limited in this embodiment.

[0068] In the magnetic modulation current sensor 10 provided in this embodiment, when the measured coil 20 is passed with current, this type of annular structure gathers the current in this type of annular structure. If the current on the measured coil 20 is large, the leakage magnetic intensity at the air gap 110 is generally strong. Therefore, the magnetic shunt structure 14 is used to perform magnetic shunt processing on the leakage magnetic generated at the air gap 110, which can greatly reduce the magnetic field detected by the magnetic modulation sensor chip 13 placed on the left and right sides of the magnetic flux guide, realize the function of large current detection, expand the measurement range of the magnetic modulation current sensor 10, and realize dual-range measurement (low-range measurement and high-range measurement). In addition, by increasing the number of magnetic modulation sensor chips 13, the measurement range of the magnetic modulation current sensor 10 can also be expanded. 44N magnetic modulation sensor chips 13 are symmetrically distributed in pairs, and can be used for different measurement tasks and measurement scenario requirements respectively. This layout helps to realize multi-dimensional magnetic field detection and improve the accuracy and reliability of measurement. Experimental verification shows that the magnetic modulation current sensor 10 designed in this embodiment has the advantages of wide range, high resolution and high linearity, and has broad application scenarios in new energy vehicles, clean energy industry and other electrical related fields.

[0069] In some embodiments, referring to FIG. 3 , the sampling circuit 16 includes a sampling unit 161 , a level conversion circuit 162 , and a digital sampling filter circuit 163 .

[0070] The sampling unit 161 is connected to the output end of the signal amplifying circuit 15 to obtain the first voltage signal. The sampling unit 161 can also extract signal samples from other nodes of the magnetic modulation current sensor 10 for monitoring and analysis. The sampling unit 161 is used for voltage sampling.

[0071] The level conversion circuit 162 is connected to the output end of the sampling unit 161, and is used to convert the negative voltage signal in the first voltage signal into a positive voltage signal and then output a second voltage signal. The level conversion circuit 162 may include an inverting amplifier. The inverting amplifier is composed of a differential input stage and a differential amplifier stage, and can invert and amplify the input signal. Therefore, by connecting the negative voltage to the non-inverting input end of the inverting amplifier, the negative voltage can be converted into a positive voltage.

[0072] The digital sampling filter circuit 163 is connected to the output end of the level conversion circuit 162, and is used to filter the second voltage signal, and convert the filtered second voltage signal into the digital signal for output. The digital sampling filter circuit 163 may include a filter circuit and an analog-to-digital conversion circuit, the input end of the filter circuit is connected to the output end of the level conversion circuit 162, and the output end of the filter circuit is connected to the input end of the analog-to-digital conversion circuit. The output end of the analog-to-digital conversion circuit is the output end of the digital sampling filter circuit 163, which is used to output the digital signal.

[0073] The output end of the digital sampling filter circuit 163 can be connected to a display device to observe the magnetic field changes on the first half magnetic ring 11 and the second half magnetic ring 12 .

[0074] In some embodiments, see FIG4 , the magnetic modulation current sensor 10 further includes a feedback coil 17. The feedback coil 17 can be disposed on the first half magnetic ring 11 or on the second half magnetic ring 12. The feedback coil 17 can also be disposed on the first half magnetic ring 11 or on the second half magnetic ring 12.

[0075] The sampling unit 161 is also used for the first voltage signal or the externally input preset voltage signal to output a control voltage. The feedback coil 17 is used to generate a feedback current under the action of the control voltage, and the feedback current is used to keep the first half magnetic ring 11 and the second half magnetic ring 12 at zero magnetic flux. The sampling unit 161 can also collect the feedback current and output it to the level conversion circuit 162, and then the level conversion circuit 162 outputs the feedback current to the digital sampling filter circuit 163, and finally outputs a digital signal corresponding to the feedback current. Among them, the externally input preset voltage signal is used to control the size of the feedback current according to actual needs.

[0076] The feedback current is used to generate a magnetic field opposite to the primary current (the current on the measured coil) to achieve the feedback effect. The number of turns of the feedback coil 17 can be set according to actual needs, and this embodiment does not limit it.

[0077] Optionally, the sampling unit 161 includes a transmission unit 164 and a feedback control unit 165. The transmission unit 164 is used to receive the first voltage signal. The feedback control unit 165 is connected to the output end of the transmission unit 164 and is also connected to the feedback coil 17. The feedback control unit 165 is used to control the magnitude of the feedback current on the feedback coil 17 according to the first voltage signal. The feedback control unit 165 is, for example, a feedback controller, used to control the magnitude of the feedback current according to the first voltage signal.

[0078] The feedback coil 17 provided in this embodiment may also be used to implement functions such as range switching, gain adjustment or noise suppression. The feedback coil 17 combines multiple structures to enable the first half magnetic ring 11 and the second half magnetic ring 12 to achieve an effect close to zero magnetic flux. In addition, the magnetic modulation current sensor 10 provided in this embodiment can obtain a larger range in the dynamic equilibrium zero magnetic flux state, thereby improving the measurement range of the magnetic modulation current sensor 10.

[0079] In some embodiments, referring to FIG. 5 , the signal amplifying circuit 15 includes: 4N first-stage signal amplifying units 151 and a power amplifying circuit 152 .

[0080] One first-level signal amplification unit 151 is connected to one magnetic modulation sensor chip 13, and different first-level signal amplification units 151 are connected to different magnetic modulation sensor chips 13. The first-level signal amplification unit 151 is used to perform first-level amplification processing on the electrical signal output by the connected magnetic modulation sensor chip 13. 4N first-level signal amplification units 151 output a third voltage signal. The main function of the 4N first-level signal amplification units 151 is to enhance the weak input signal collected by the four-way magnetic modulation chip to a certain amplitude for the convenience of subsequent circuit processing.

[0081] The first-stage signal amplifying unit 151 may include at least one operational amplifier.

[0082] The power amplifier circuit 152 is connected to the output ends of the 4N first-level signal amplification units 151, and is used to output the first voltage signal after performing a second-level amplification process on the third voltage signal. The function of the power amplifier circuit 152 is to further amplify the third voltage to drive the subsequent circuit. In order to enable the power amplifier circuit 152 to be used with the magnetic modulation current sensor 10 in multiple ranges, the power amplifier circuit 152 can retain more current driving capacity and heat dissipation capacity, and a power amplifier powered by dual power supplies can be selected.

[0083] Please refer to FIG. 6 , optionally, the power amplifier circuit 152 includes a dual power amplifier 153 , a first filter capacitor group 154 ​​and a second filter capacitor group 155 .

[0084] A dual power amplifier 153, a first end of which receives the third voltage signal, and a second end of which is connected to the output end of the dual power amplifier 153. A first filter capacitor group 154 ​​is connected to the first power input end of the dual power amplifier 153. A second filter capacitor group 155 is connected to the second power input end of the dual power amplifier 153.

[0085] The first filter capacitor group 154 ​​includes a plurality of first capacitors 156 (capacitor C1 as shown in the figure). The first end of the first capacitor 156 is connected to the first power supply and the first power supply input terminal, and the second end of the first capacitor 156 is grounded. The first end of the first capacitor 156 is also connected to the first end of the adjacent first capacitor 156, and the second end of the first capacitor 156 is also connected to the second end of the adjacent first capacitor 156. In other words, the plurality of first capacitors 156 are connected in parallel.

[0086] The second filter capacitor group 155 includes a plurality of second capacitors 157 (capacitor C2 as shown in the figure). The first end of the second capacitor 157 is connected to the second power supply and the second power supply input terminal, and the second end of the second capacitor 157 is grounded. The first end of the second capacitor 157 is also connected to the first end of the adjacent second capacitor 157, and the second end of the second capacitor 157 is also connected to the second end of the adjacent second capacitor 157. In other words, the plurality of second capacitors 157 are connected in parallel.

[0087] Preferably, the first filter capacitor group 154 ​​and the second filter capacitor group 155 have the same structure, the first filter capacitor group 154 ​​includes three first capacitors 156 , and the second filter capacitor group 155 includes three second capacitors 157 .

[0088] When the dual power supply amplifier 153 is powered by dual power supplies, the power supply range of the dual power supply is ±4V volts (V for short) to ±30V, and a maximum continuous current of 8 amperes (A for short) can be provided, meeting the supply requirements of the magnetic modulation current sensor 10. The bandwidth requirements of the dual power supply amplifier 153 meet the commonly used large current measurement requirements. The slew rate of the dual power supply amplifier 153 can be 9 volts per microsecond (V / us), which can ensure the integrity of the waveform. The voltage noise of the dual power supply amplifier 153 can be 705 volts per microhertz (nV / VHz) with a power supply rejection ratio of approximately 92 decibels (dB) to match the higher range of the magnetic modulation current sensor 10.

[0089] In some embodiments, the present application further provides a magnetic field monitoring device, which includes a monitor and the magnetic modulation current sensor 10 provided in any of the above embodiments.

[0090] The monitor is connected to the output end of the sampling circuit 16 in the magnetic modulation current sensor 10, and is used to display the magnetic field changes of the first half magnetic ring 11 and the second half magnetic ring 12 in the magnetic modulation current sensor 10 according to the multiple digital signals output by the sampling circuit 16 over a period of time. The monitor can also display the changes of the feedback current described above. The monitor can be a television, a computer, etc., which is not limited in this embodiment.

[0091] In the description of this specification, the description with reference to the terms "some embodiments", "other 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 application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0092] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0093] 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 modulation current sensor, It is characterized in that include: A first half magnetic ring and a second half magnetic ring are arranged opposite to each other, wherein the first half magnetic ring and the second half magnetic ring form a ring-like structure with two air gaps; The coil under test passes through the hole formed by the ring-like structure; 4N magnetic modulation sensor chips, wherein 2N magnetic modulation sensor chips are arranged between one air gap and the coil to be measured, and another 2N magnetic modulation sensor chips are arranged between another air gap and the coil to be measured; N is a natural number greater than zero; A magnetic shunt structure, disposed at any of the air gaps, the magnetic shunt structure being connected to an input end of each of the magnetic modulation sensor chips; a signal amplifying circuit connected to the output end of each of the magnetic modulation sensor chips, and configured to amplify the electrical signals output by the 4N magnetic modulation sensor chips and output a first voltage signal; The sampling circuit is connected to the output end of the signal amplifying circuit and is used to output a digital signal according to the first voltage signal, wherein the digital signal is used to characterize the magnitude of the first voltage signal.

2. The magnetic modulation current sensor according to claim 1, It is characterized in that The sampling circuit comprises: a sampling unit, connected to the output end of the signal amplifying circuit, and used for acquiring the first voltage signal; a level conversion circuit connected to the output end of the sampling unit, and configured to convert a negative voltage signal in the first voltage signal into a positive voltage signal and then output a second voltage signal; The digital sampling filter circuit is connected to the output end of the level conversion circuit, and is used for filtering the second voltage signal, converting the filtered second voltage signal into the digital signal and outputting it.

3. The magnetic modulation current sensor according to claim 2, It is characterized in that The sampling unit is further used to output a control voltage according to the first voltage signal or an externally input preset voltage signal; The magnetic modulation current sensor further comprises: A feedback coil is arranged on the first half magnetic ring and / or arranged on the second half magnetic ring; The feedback coil is connected to the output end of the sampling unit; The feedback coil is used to generate a feedback current under the action of the control voltage, and the feedback current is used to keep the first half magnetic ring and the second half magnetic ring at zero magnetic flux.

4. The magnetic modulation current sensor according to claim 3, It is characterized in that The sampling unit comprises: A transmission unit, configured to receive the first voltage signal; A feedback control unit is connected to the output end of the transmission unit and is also connected to the feedback coil. The feedback control unit is used to control the magnitude of the feedback current on the feedback coil according to the first voltage signal.

5. The magnetic modulation current sensor according to any one of claims 1 to 4, It is characterized in that The signal amplification circuit comprises: 4N first-level signal amplification units, wherein different first-level signal amplification units are connected to different magnetic modulation sensor chips, and the first-level signal amplification units are used to perform first-level amplification processing on the electrical signal output by the connected magnetic modulation sensor chip; the 4N first-level signal amplification units output a third voltage signal; The power amplifier circuit is connected to the output ends of the 4N first-level signal amplification units, and is used to output the first voltage signal after performing a second-level amplification process on the third voltage signal.

6. The magnetic modulation current sensor according to claim 5, It is characterized in that The power amplifier circuit comprises: A dual-power amplifier, wherein a first terminal of the dual-power amplifier receives the third voltage signal, and a second terminal of the dual-power amplifier is connected to an output terminal of the dual-power amplifier; A first filter capacitor group is connected to a first power input terminal of the dual power amplifier; The second filter capacitor group is connected to the second power input terminal of the dual power amplifier.

7. The magnetic modulation current sensor according to claim 6, It is characterized in that The first filter capacitor group includes: A plurality of first capacitors, wherein first ends of the first capacitors are connected to the first power supply and the first power supply input terminal, and second ends of the first capacitors are grounded; The first end of the first capacitor is further connected to the first end of the adjacent first capacitor, and the second end of the first capacitor is further connected to the second end of the adjacent first capacitor.

8. The magnetic modulation current sensor according to claim 6, It is characterized in that The second filter capacitor group includes: A plurality of second capacitors, wherein first ends of the second capacitors are connected to the second power supply and the second power supply input terminal, and second ends of the second capacitors are grounded; The first end of the second capacitor is further connected to the first end of the adjacent second capacitor, and the second end of the second capacitor is further connected to the second end of the adjacent second capacitor.

9. The magnetic modulation current sensor according to claim 1, It is characterized in that The two air gaps are symmetrically arranged along a first direction, and the 2N magnetic modulation sensor chips on one side are symmetrically arranged along a second direction; The first direction and the second direction are perpendicular to each other.

10. A magnetic field monitoring device, It is characterized in that A magnetic modulation current sensor comprising a monitor and any one of claims 1 to 9; The monitor is connected to the output end of the sampling circuit in the magnetic modulation current sensor, and is used to display the magnetic field changes of the first half magnetic ring and the second half magnetic ring in the magnetic modulation current sensor according to multiple digital signals output by the sampling circuit over a period of time.

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