CN106291061B - A kind of current sensor, processing module and current measuring method - Google Patents
A kind of current sensor, processing module and current measuring method Download PDFInfo
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Abstract
The invention discloses current sensors, including at least three magnetic transducing units and processing module, processing module include storage unit and computing unit；Magnetic transducing unit is looped around around tested cable, and magnetic transducing unit is in same plane, and there are a crosspoint in the central axes of the plane and tested cable；The invention also discloses a kind of processing modules, for calculating the current value of more measured wires；Also disclose current measuring method.Current sensor of the invention does not include magnetic core, therefore overcomes magnetic core bring and be easily saturated and defect at high cost, meanwhile, the present invention can disposably measure the current value of multiple conducting wires.
Description
Technical Field
The invention relates to the technical field of current sensors, in particular to a current sensor, a processing module and a current measuring method.
Background
The current sensor is widely applied to the fields of new energy, intelligent traffic, industrial control, intelligent household appliances, intelligent power grids and the like.
The commonly used current sensor uses a hall element or an inductance coil as a sensitive element, and is divided into two types of open-loop type and closed-loop type: the open-loop current sensor is characterized in that a magnetic core with an air gap is arranged around a measured lead, a magnetic sensing unit is positioned in the air gap, the magnetic core generates induced electric potential due to the law of electromagnetic induction, the magnetic sensing unit can measure a magnetic field at the air gap of the magnetic core, and the rear end can calculate the magnitude of the measured current according to an output signal of the magnetic sensing unit.
The working mode of the open-loop current sensor is to directly measure a magnetic field, so that magnetic hysteresis and saturation of a magnetic core can occur under the action of large current, and the measurement precision is influenced. To overcome the above problems, those skilled in the art measure the current using a closed loop current sensor. The closed-loop current sensor is characterized in that a compensation coil is wound on a magnetic core of the closed-loop current sensor and is electrically connected with a magnetic sensing unit, the compensation coil is powered by output voltage of the magnetic sensing unit and is used for compensating a magnetic field generated by current to be measured, and when magnetic balance is achieved, the magnetic field generated by the compensation current is approximately the same as the magnetic field generated by the current to be measured, so that the magnetic core normally works in an environment without magnetic flux or with small magnetic flux, and hysteresis and saturation can be overcome. The rear end can directly measure the current of the compensation coil to calculate the measured current.
In both the open-loop and closed-loop current sensors, the magnetic core is used, and the processing cost of the magnetic core is high, so that the cost of the corresponding current sensor is high.
At present, a common three-phase electric cable is a cable comprising three conducting wires, the current sensor measures current in a mode of approaching each conducting wire to measure the current value of each conducting wire, and the current of each conducting wire cannot be accurately measured at one time for the three conducting wires coated in one cable. Further, the cable coated with a plurality of current wires is further incapable of being accurately measured at one time.
Disclosure of Invention
The technical problem to be solved by the present invention is to overcome the defects of the prior art, and to provide a current sensor, a processing module and a current measuring method, wherein the current sensor does not include a magnetic core, thereby overcoming the defects of easy saturation and high cost caused by the magnetic core, and simultaneously, the current value of each current wire of a plurality of wires can be measured at one time.
The invention adopts the following technical scheme for solving the technical problems:
the current sensor comprises at least three magnetic sensing units and a processing module, wherein the processing module comprises a storage unit and a calculation unit; the magnetic sensing units are all arranged around the cable to be tested and on the same plane, and an intersection point is formed between the plane and the central axis of the cable to be tested; wherein,
a magnetic sensing unit for transmitting the measured magnetic field to a computing unit;
a storage unit for storing the included angle delta theta and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a calculation unit for determining a and thetanAccording to a and thetanMagnetic field measured by a plurality of magnetic sensor units, delta theta and R stored in a memory unitnCalculating the current values of a plurality of tested leads in the tested cable; wherein a is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface where the plane of the magnetic sensing unit is intersected with each current lead in the tested cable respectively(ii) a The intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
As a further optimization scheme of the current sensor, the distances between the adjacent magnetic sensing units are equal.
A processing module is used for calculating the current values of a plurality of tested leads and comprises a storage unit and a calculation unit; wherein,
a storage unit for storing the included angle delta theta and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a calculating unit for receiving the magnetic fields measured by the plurality of magnetic sensing units and determining a and thetanAccording to a and thetanMagnetic field measured by a plurality of magnetic sensor units, delta theta and R stored in a memory unitnCalculating the current values of a plurality of tested leads in the tested cable; wherein a is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface where the plane where the magnetic sensing unit is located and each current lead in the tested cable are respectively crossed; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
A current sensor comprises at least three magnetic sensing units and a processing module, wherein the processing module comprises a storage unit and a calculation unit; the magnetic sensing units are all arranged around the cable to be tested, the magnetic sensing units are all arranged on the same plane, an intersection point is formed between the plane and the central axis of the cable to be tested, and the distances from each magnetic sensing unit to the intersection point are equal; wherein,
a magnetic sensing unit for transmitting the measured magnetic field to a computing unit;
the storage unit is used for storing an included angle delta theta, and the delta theta is an included angle between a connecting line between adjacent magnetic sensing units and the intersection point;
a calculation unit for determining a and thetanAccording to a and thetanCalculating the current values of a plurality of tested leads in the tested cable according to the magnetic fields measured by the plurality of magnetic sensing units and the delta theta stored in the storage unit; wherein a is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface where the plane where the magnetic sensing unit is located and each current lead in the tested cable are respectively crossed; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
As a further optimization scheme of the current sensor, the distances between the adjacent magnetic sensing units are equal.
A processing module is used for calculating the current values of a plurality of tested leads and comprises a storage unit and a calculation unit; wherein,
the storage unit is used for storing an included angle delta theta, and the delta theta is an included angle between a connecting line between adjacent magnetic sensing units and the intersection point;
a calculating unit for receiving the magnetic fields measured by the plurality of magnetic sensing units and determining a and thetanAccording to a and thetanCalculating the current values of a plurality of tested leads in the tested cable according to the magnetic fields measured by the plurality of magnetic sensing units and the delta theta stored in the storage unit; where a is the center distance of the cross section of the adjacent current conductor, which is the magnetic sensing unitThe plane where the current conducting wires are respectively intersected with each current conducting wire in the tested cable; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
A current sensor comprises at least three magnetic sensing units and a processing module, wherein the processing module comprises a storage unit and a calculation unit; the magnetic sensing units are all arranged around the cable to be tested and on the same plane, and an intersection point is formed between the plane and the central axis of the cable to be tested; wherein,
a magnetic sensing unit for transmitting the measured magnetic field to a computing unit;
a storage unit for storing the included angle delta theta and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a calculating unit for calculating Δ θ and R stored in the storage unit based on the magnetic fields measured by the plurality of magnetic sensing unitsnAnd calculating the current values of a plurality of tested leads in the tested cable.
As a further optimization scheme of the current sensor, the distances between the adjacent magnetic sensing units are equal.
A processing module is used for calculating the current values of a plurality of tested leads and comprises a storage unit and a calculation unit; wherein,
a storage unit for storing the included angle delta theta and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a computing unit for receiving multiple magnetic fieldsMagnetic field measured by the sensing units, and based on the magnetic fields measured by the plurality of magnetic sensing units, Δ θ and R stored in the storage unitnAnd calculating the current values of a plurality of tested leads in the tested cable.
A current measurement method comprising the steps of:
a measurement step: at least three magnetic sensing units are adopted to surround the cable to be detected, the magnetic sensing units are all on the same plane, and an intersection point is formed between the plane and the central axis of the cable to be detected;
a storage step: storing the angle Δ θ and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a calculation step: magnetic field, Delta theta, and R measured from a plurality of magnetic sensing unitsnAnd calculating the current values of a plurality of tested leads in the tested cable.
A current measurement method comprising the steps of:
a measurement step: at least three magnetic sensing units are adopted to surround the periphery of the tested cable, the magnetic sensing units are all on the same plane, an intersection point is arranged between the plane and the central axis of the tested cable, and the distances from each magnetic sensing unit to the intersection point are equal;
a storage step: storing an included angle delta theta, wherein the included angle delta theta is an included angle between a connecting line between adjacent magnetic sensing units and an intersection point;
a calculation step: and calculating the current values of a plurality of tested leads in the tested cable according to the magnetic fields measured by the plurality of magnetic sensing units and the delta theta.
A current measurement method comprising the steps of:
a measurement step: at least three magnetic sensing units are adopted to surround the cable to be detected, the magnetic sensing units are all on the same plane, and an intersection point is formed between the plane and the central axis of the cable to be detected;
a storage step: storing the angle Δ θ and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a calibration step: determining a and thetanA is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface of the intersection of the plane where the magnetic sensing unit is located and each current lead in the tested cable; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanSelecting a radius on the cross section of the tested cable, wherein the radius is an included angle value of a connecting line of the nth magnetic sensing unit, and the connecting line of the nth magnetic sensing unit is a connecting line of the nth magnetic sensing unit and a central point on the cross section of the tested cable;
a calculation step: magnetic field, delta theta, R measured from a plurality of magnetic sensing unitsnA and thetanAnd calculating the current values of a plurality of tested leads in the tested cable.
A current measurement method comprising the steps of:
a measurement step: at least three magnetic sensing units are adopted to surround the periphery of the tested cable, the magnetic sensing units are all on the same plane, an intersection point is arranged between the plane and the central axis of the tested cable, and the distances from each magnetic sensing unit to the intersection point are equal;
a storage step: storing an included angle delta theta, wherein the included angle delta theta is an included angle between a connecting line between adjacent magnetic sensing units and an intersection point;
a calibration step: determining a and thetanA is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface of the intersection of the plane where the magnetic sensing unit is located and each current lead in the tested cable; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanFor selecting on the cross section of the cable to be testedA radius, the included angle value of the connecting line of the radius and the nth magnetic sensing unit, wherein the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable;
a calculation step: magnetic field, delta theta, a and theta measured from a plurality of magnetic sensing unitsnAnd calculating the current values of a plurality of tested leads in the tested cable.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects: the current sensor does not comprise a magnetic core, so that the defects of easy saturation and high cost caused by the magnetic core are overcome, and meanwhile, the current sensor can measure the current values of a plurality of wires at one time.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the current sensor of the present invention.
The reference numerals in the figures are to be interpreted: 21-the cable to be tested, 31, 32, 33 all being current conducting wires, 41-insulating layer, A1-AnAre the 1 st to nth magnetic sensing units.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, one embodiment of the current sensor of the present invention comprises: a plurality of three or more magnetic sensor units A1、A2、A3……An(subscript n represents the nth magnetic sensor sheetMeta) and a processing module (not shown). The magnetic sensing units are all arranged around the cable to be tested and on the same plane, and an intersection point O is formed between the plane and the central axis of the cable to be tested; the magnetic sensing units are used for measuring the magnetic field at the position and outputting a plurality of groups of output signals to the processing module, the processing module comprises a calculating unit and a storage unit, the storage unit stores an included angle delta theta, the included angle delta theta is an included angle between the adjacent magnetic sensing units and a connecting line between the adjacent magnetic sensing units and the intersection point O, and the calculating unit calculates the current values of a plurality of measured wires in the measured cable according to the plurality of groups of output signals and the included angle delta theta.
The magnetic sensing units are fixed on the printed circuit board or the framework and arranged along the periphery of the tested cable 21, the magnetic sensing units are all arranged around the periphery of the tested cable, the magnetic sensing units are all on the same plane, an intersection point O is formed between the plane and the central axis of the tested cable, the plane where the magnetic sensing units are located and the intersection surface of the tested cable are called the cross section of the tested cable 21, and the central point of the cross section of the tested cable 21 is the intersection point O. The tested cable 21 is a three-phase line cable, three current leads 31, 32 and 33 in the tested cable are coated with insulating layers 41 and arranged in an equilateral triangle, and three-phase currents I with phases which are different by 120 degrees in pairs are respectively conducted1、I2、I3. The distance R from each magnetic sensing unit to the center point of the cross section of the tested cable 21 is knownnThe plane where the magnetic sensing units are located and the current leads 31, 32, 33 intersect is called the current lead 31, 32, 33 cross section (hereinafter referred to as "measuring distance"), the center distance of the adjacent current lead cross section is a (hereinafter referred to as "center distance"), the included angle between the connecting lines between the adjacent magnetic sensing units and the center point O (intersection point) of the cross section of the tested cable is Δ θ (hereinafter referred to as "included angle"), and the position angle of the nth magnetic sensing unit is θn(hereinafter, simply referred to as "position angle"), θnIn order to select a radius on the cross section of the tested cable, the radius can be called as a standard radius, the included angle value of the standard radius and the connecting line of the nth magnetic sensing unit is the included angle value, and the cross section of the tested cable is the surface of the intersection of the plane where the magnetic sensing units are located and the tested cableThe connection line of the nth magnetic sensing unit is the connection line of the nth magnetic sensing unit and the central point on the cross section of the tested cable; wherein the position angle of the first magnetic sensing unit 1 is theta1And then:
θn＝θ1+(n-1)Δθ
when the device works, the current sensors are arranged around the tested cable 21, and the magnetic field B of the position where the magnetic sensing units are located is measured in real time by the magnetic sensing units1、B2……BnAccording to the common physical knowledge, the magnetic field B at any position can be known by combining the structure of the current sensor of the inventionnIs a current I1、I2、I3Position angle thetanMeasuring the distance RnA function of the center distance a, and the function is defined as A (I)1,I2,I3,Rn,θnAnd a), then:
Bn＝A(I1,I2,I3,Rn,θn,a)
if the measured distance R of each magnetic sensor unitnEqual to R, the magnetic field B at any positionnIs a current I1、I2、I3Position angle thetanAnd a function of the center-to-center distance a, the function being F (I)1,I2,I3,θnAnd a), then:
Bn＝F(I1,I2,I3,θn,a)
as can be seen from the above, BnFor the measured values, B, which are known, can be measured by the computing unit by means of at least 5 magnetic sensor unitsnValue calculation I1、I2、I3If an exact solution is required, at least 6 magnetic sensing units are required.
Hereinafter, an accurate solution for measuring the current value of 3 wires is provided by taking a current sensor provided with 6 magnetic sensing units as an example.
Generally, the alternating current I is a periodic function of time t:
let current I of conductor 311：I1＝f1(t)；
Setting the current I of the conductor 322：I2＝f2(t)；
Current I provided to conductor 333：I3＝f3(t)；
F is adopted due to different periodic function relations of time t and current I in different electricity utilization environments1(t)、f2(t)、f3(t) denotes the current I1、I2、I3As a function of time t.
Then at a position angle of thetanThe magnetic field distribution at the location is calculated as follows:
tangential magnetic field Bn：
Bn＝cosθn·Bx-sinθn·By (3)
Where x is an axis parallel to the standard radius and the y-axis is an axis perpendicular to the standard radius. Therefore BxIs thetanComponent of the total magnetic field B at the location in the direction of the x-axis, ByIs the component of B in the y-axis direction, BnIs the component of B in the tangential direction of the nth magnetic sensor cell (in this embodiment, the magnetic field B measured by each magnetic sensor cellnA tangential component of the total magnetic field B), i.e. the measured value of the nth magnetic sensor cell.
Since each one isMeasuring distance R of magnetic sensor unitnAre all the same and are all R, so that the tangential magnetic field is only I1,、I2、I3A and theta1(since Δ θ is known, θnIs theta1Function of (d).
Measuring the tangential magnetic field B of the 6 magnetic sensing units1、B2……B5、B6Then the following equation can be obtained, which will be θn＝θ1Substitution of + (n-1) Δ θ into Bn＝F(I1,I2,I3,θnA) (n denotes the nth magnetic sensor cell, in this embodiment, n is 1,2,3,4,5, or 6), the equation set is obtained:
introduction about I1,I2,I3,θ1And a new function Gn(I1,I2,I3,θ1A), let:
obtaining:
wherein:
written as an iterative equation:wherein, XkRepresents X obtained by iterating k times, and is the difference value, G ', of numerical solutions obtained by iterating two times'n(Xk) Is Gn(Xk) A derivative of (a);
g is to ben(X) are each independently to I1,I2,I3,θ1And a partial derivative, combining an iterative equation, and obtaining a matrix equation:
setting a convergence condition:a solution of the system of equations can be obtained, where Δ I1、ΔI2、ΔI2、Δa、Δθ1Respectively represent I1、I2、I2、a、θ1And the difference value of the numerical solutions of the two iterations, wherein epsilon is a constant with a small limit, is used for determining the calculation precision, and represents that when the square difference of the solutions obtained by the current two iteration solutions is smaller than epsilon, the result meets a certain precision requirement.
The solution of the equation set (7) calculated by the 5 magnetic field measurement values is not accurate, and for accurate solution, the 6 th magnetic sensing unit is required to measure the magnetic field B at the position of the magnetic sensing unit6The solution is required to satisfy:
|F(I1,I2,I3,θ1+5Δθ,a)-B6|<εfat the same time, attention is paid to exclude a<The incomprehension of 0, the solution can be solved exactly. Wherein epsilonfIs another constant with a small limit to determine the calculation accuracy.
Due to the symmetry of the relative position of the conductive lines of each phase, assume(m ∈ Z, where T is the matrix transpose sign, whereAnd a*Are respectively I1、I2、I2、θ1And the solution of a) is a solution of the system of equations, thenAnd also the solution of the equation set, therefore, it is necessary to prevent iterative solution from converging to different equivalent solutions, causing confusion in the definition of the wire numbers of each phase, making the output discontinuous, and to achieve calibration of the wire position before measurement, i.e. determining θ by solving the above-mentioned five-order nonlinear matrix equation (7)1And a.
After calibration, the current value is measured in real time, and theta can not be considered1(due to determination of θ)1And Δ θ is known, θnIs theta1And Δ θ, so θnAlso determined) and a, only the solution is required:
the calculation can be greatly simplified.
As can be derived from the above embodiment, the calculation unit determines θ by performing a calibration step1After a, measuring the magnetic field value B in real time1、B2……BnThe method is used for calculating the currents of the multiple leads, and the calculation speed is improved due to the simplification of the calculation, so that the current values of the multiple leads can be accurately measured in real time. However, it is easy to see that the calibration step itself can accurately measure the current values of the plurality of wires, but the speed is slow, and real-time measurement cannot be realized, so that the calculation unit solving the five-order nonlinear matrix equation (7) can be used as a calibration step for measuring the current values of the plurality of wires in real time, and can also be used as a calibration unitA measuring method for accurately measuring the current values of a plurality of wires. The more magnetic sensing units are provided, the higher the measurement accuracy.
In the above current sensor, the measurement distance R of each magnetic sensing unitnThe included angle Δ θ between each magnetic sensor unit may be different. But with a different measured distance R for each magnetic sensor unitnAnd the different angle delta theta between each magnetic sensing cell is stored as a known value in the memory cell if RnThe same (both R), then this R value need not be stored in the memory cell.
In the current sensor, the current to be measured may be either an alternating current or a direct current.
It should be noted that the above-described current sensor employs the determined position angle θ of the 1 st magnetic sensing unit1The calibration is performed, but not limited to this in practical operation, and since Δ θ is known, only the position angle θ of any one magnetic sensing unit needs to be determinednAnd obtaining the position angle of other magnetic sensing units. Meanwhile, each magnetic sensing unit in the above embodiments measures a tangential field, and actually can measure magnetic fields in other directions as required.
In the current sensor, the plurality of magnetic sensing units may be independently arranged or connected in parallel.
In the above current sensor, any one magnetic sensing unit is a single resistor, a half bridge or a full bridge structure, the single resistor includes a magnetic resistor, the half bridge includes two magnetic resistors connected in series, the full bridge includes two half bridges connected in parallel.
In the current sensor, the magnetoresistance is formed by one magnetic sensor element, or more than two magnetic sensor elements are connected in parallel and/or in series. The beneficial effect of connecting a plurality of magnetic sensing elements in series and/or in parallel is that the problem of Uniformity (Uniformity) of the magnetic sensing elements in nano-processing or micro-processing can be solved by presetting the number of the magnetic sensing elements, and meanwhile, the electronic tunneling probability of the magnetic sensing elements can be reduced, and the electrostatic protection capability of the magnetic sensing elements can be improved.
In the above current sensor, the magnetic sensing element includes a hall element, an anisotropic magnetoresistive element, a giant magnetoresistive element, or a magnetic tunnel junction element. The anisotropic magneto-resistance element, the giant magneto-resistance element and the magnetic tunnel junction element have high sensitivity, high precision, small volume (micron and nanometer level) and good temperature drift performance, so that the current sensor adopting the magneto-resistance element can realize small-volume integration.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. The current sensor is characterized by comprising at least three magnetic sensing units and a processing module, wherein the processing module comprises a storage unit and a calculation unit; the magnetic sensing units are all arranged around the cable to be tested and on the same plane, and an intersection point is formed between the plane and the central axis of the cable to be tested; wherein,
a magnetic sensing unit for transmitting the measured magnetic field to a computing unit;
a storage unit for storing the included angle delta theta and the distance RnAnd Δ θ is the adjacent magnetismAngle between the sensing unit and the line between the points of intersection, RnIs the distance of each magnetic sensing cell to the intersection point;
a calculation unit for determining a and thetanAccording to a and thetanMagnetic field measured by a plurality of magnetic sensor units, delta theta and R stored in a memory unitnCalculating the current values of a plurality of tested leads in the tested cable; wherein a is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface where the plane where the magnetic sensing unit is located and each current lead in the tested cable are respectively crossed; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
2. A current sensor according to claim 1, wherein the distances between adjacent magnetic sensing units are equal.
3. A processing module is used for calculating the current values of a plurality of tested leads and is characterized by comprising a storage unit and a calculation unit; wherein,
a storage unit for storing the included angle delta theta and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a calculating unit for receiving the magnetic fields measured by the plurality of magnetic sensing units and determining a and thetanAccording to a and thetanMagnetic field measured by a plurality of magnetic sensor units, delta theta and R stored in a memory unitnCalculating the current values of a plurality of tested leads in the tested cable; wherein a is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface where the plane where the magnetic sensing unit is located and each current lead in the tested cable are respectively crossed; plane where magnetic sensing unit is located and tested cableThe intersecting surface is the cross section of the cable to be tested, thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
4. The current sensor is characterized by comprising at least three magnetic sensing units and a processing module, wherein the processing module comprises a storage unit and a calculation unit; the magnetic sensing units are all arranged around the cable to be tested, the magnetic sensing units are all arranged on the same plane, an intersection point is formed between the plane and the central axis of the cable to be tested, and the distances from each magnetic sensing unit to the intersection point are equal; wherein,
a magnetic sensing unit for transmitting the measured magnetic field to a computing unit;
the storage unit is used for storing an included angle delta theta, and the delta theta is an included angle between a connecting line between adjacent magnetic sensing units and the intersection point;
a calculation unit for determining a and thetanAccording to a and thetanCalculating the current values of a plurality of tested leads in the tested cable according to the magnetic fields measured by the plurality of magnetic sensing units and the delta theta stored in the storage unit; wherein a is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface where the plane where the magnetic sensing unit is located and each current lead in the tested cable are respectively crossed; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
5. A current sensor according to claim 4, wherein the distance between adjacent magnetic sensing elements is equal.
6. A processing module is used for calculating the current values of a plurality of tested leads and is characterized by comprising a storage unit and a calculation unit; wherein,
the storage unit is used for storing an included angle delta theta, and the delta theta is an included angle between a connecting line between adjacent magnetic sensing units and the intersection point;
a calculating unit for receiving the magnetic fields measured by the plurality of magnetic sensing units and determining a and thetanAccording to a and thetanCalculating the current values of a plurality of tested leads in the tested cable according to the magnetic fields measured by the plurality of magnetic sensing units and the delta theta stored in the storage unit; wherein a is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface where the plane where the magnetic sensing unit is located and each current lead in the tested cable are respectively crossed; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanIn order to select a radius on the cross section of the tested cable, the included angle value of the radius and the connecting line of the nth magnetic sensing unit is the connecting line of the nth magnetic sensing unit and the central point on the cross section of the tested cable.
7. A current measuring method, comprising the steps of:
a measurement step: at least three magnetic sensing units are adopted to surround the cable to be detected, the magnetic sensing units are all on the same plane, and an intersection point is formed between the plane and the central axis of the cable to be detected;
a storage step: storing the angle Δ θ and the distance RnΔ θ is the angle between the line connecting the adjacent magnetic sensing cells and the intersection point, RnIs the distance of each magnetic sensing cell to the intersection point;
a calibration step: determining a and thetanA is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface of the intersection of the plane where the magnetic sensing unit is located and each current lead in the tested cable; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanSelecting a radius on the cross section of the tested cable, wherein the included angle value of the radius and the connecting line of the nth magnetic sensing unit and the nth magnetic sensing unitThe connecting line is a connecting line of the nth magnetic sensing unit and the central point on the section of the tested cable;
a calculation step: magnetic field, delta theta, R measured from a plurality of magnetic sensing unitsnA and thetanAnd calculating the current values of a plurality of tested leads in the tested cable.
8. A current measuring method, comprising the steps of:
a measurement step: at least three magnetic sensing units are adopted to surround the periphery of the tested cable, the magnetic sensing units are all on the same plane, an intersection point is arranged between the plane and the central axis of the tested cable, and the distances from each magnetic sensing unit to the intersection point are equal;
a storage step: storing an included angle delta theta, wherein the included angle delta theta is an included angle between a connecting line between adjacent magnetic sensing units and an intersection point;
a calibration step: determining a and thetanA is the central distance of the cross section of the adjacent current lead, and the cross section of the current lead is the surface of the intersection of the plane where the magnetic sensing unit is located and each current lead in the tested cable; the intersecting surface of the plane where the magnetic sensing unit is located and the tested cable is the section of the tested cable, and thetanSelecting a radius on the cross section of the tested cable, wherein the radius is an included angle value of a connecting line of the nth magnetic sensing unit, and the connecting line of the nth magnetic sensing unit is a connecting line of the nth magnetic sensing unit and a central point on the cross section of the tested cable;
a calculation step: magnetic field, delta theta, a and theta measured from a plurality of magnetic sensing unitsnAnd calculating the current values of a plurality of tested leads in the tested cable.
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