Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
  • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
  • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R33/00—Arrangements or instruments for measuring magnetic variables
  • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
  • G01R33/035—Measuring direction or magnitude of magnetic fields or magnetic flux using superconductive devices
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R33/00—Arrangements or instruments for measuring magnetic variables
  • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
  • G01R33/04—Measuring direction or magnitude of magnetic fields or magnetic flux using the flux-gate principle

Definitions

• the subject of the invention is that of current detection devices.
• the main source of limitation is the impedance of the branch circuit, which limits the extension of the bandwidth to high frequencies.
• the spectral response of the branch circuit is non-uniform.
• the imperfections of the spectral response can introduce a temporal distortion of the bypass current, which can be coupled to the rest of the circuit, for example altering the main current, which is particularly troublesome for the purity of the RF analog signals, or radiate electromagnetic waves (EM) parasites, which can be troublesome for the operation of neighboring components.
• EM electromagnetic waves
• the invention therefore aims to overcome this problem including providing an improved current detection device.
• the invention relates to a current detection device characterized in that it comprises: a first conductive wire traversed by an external current to be measured, the first wire creating in its vicinity an external magnetic field; a magnetometric sensor placed in the vicinity of the first conductive wire, responsive to a flux of the external magnetic field and adapted to generate a measurement signal corresponding to the external current.
• the current detection device is broadband, that is to say it has a high high cutoff frequency; it has a uniform response on this bandwidth; and outputs a current having a higher intensity than the measured bypass current, i.e. it amplifies the current to be measured.
• the current detection device comprises one or more of the following characteristics, taken individually or in any technically possible combination:
• the magnetometric sensor comprises: a magnetic sensor having a surface and generating a response signal when it is immersed in a magnetic field creating a magnetic flux through said surface; a control circuit, inputting the response signal of the magnetometer and outputting a feedback current; and a second conductive wire disposed in the vicinity of the magnetic sensor and connected at the output of the control circuit, the wire being traversed by the feedback current, the circuit and the conducting wire being such that a feedback magnetic field is created whose flow through the surface of the magnetic sensor substantially compensates, at each instant, the flow of the external magnetic field, the output signal of the measuring device being constituted by the counter-reaction current;
• the magnetic sensor is a superconducting magnetic sensor
• control circuit comprises a comparison means capable of comparing the response signal of the magnetic sensor with respect to a reference signal and of generating a comparison signal, and a current source controlled by the comparison signal, suitable for generating the counter-reaction current;
• the detection device has an extended bandwidth and a linear and uniform response on said bandwidth
• the magnetic sensor consists of a plurality of elementary magnetic sensors connected in series between input terminals of the control circuit;
• the first and second conductive wires are shaped so as to run parallel in a plane of the surface of the magnetic sensor, the external current flowing in a first direction and the counter-reaction current flowing in a second direction opposite to the first;
• the first wire and / or the second wire form a loop around the surface of the magnetic sensor, the loop comprising at least one turn;
• the magnetic sensor consisting of a plurality of elementary magnetic sensors connected in series between input terminals of the control circuit, the first and second son form a plurality of meanders around a plurality of elementary magnetometers; the elementary magnetic sensors being asymmetrical, the elementary magnetic sensors are arranged in every other meander, or, said elementary magnetic sensors being symmetrical, the elementary magnetic sensors are arranged in each meander;
• the magnetometric sensor and a portion of the first conductive wire are placed in a housing for magnetic insulation vis-à-vis the outside world.
• FIG. 1 is a basic representation of a current measuring device
• Figure 2 is a schematic representation of a so-called loop embodiment of the device of Figure 1;
• Figure 3 is a schematic representation of an intermediate embodiment of the device of Figure 1;
• FIG. 4 is a schematic representation of a meandering embodiment of the device of FIG. 1, implementing asymmetrical magnetic sensors;
• FIG. 5 is a schematic representation of a meandering embodiment of the device of FIG. 1, implementing symmetrical magnetic sensors;
• Figure 6 is a simplified representation of a two-dimensional dense integration of so-called loop embodiments.
• Figure 7 is a simplified representation of a dense two-dimensional integration of so-called meander embodiments.
• Figure 1 is shown a device 300 of current detection.
• the device 300 comprises a housing 302, a first conductive wire 306 and a magnetic sensor 310.
• the housing 302 delimits a cavity that is magnetically isolated from the outside world, in particular the earth's magnetic field or disturbing magnetic fields, such as those generated by radio waves.
• the housing 302 is made of a suitable material adapted to screen these external fields.
• the first conductive wire 306 flows from the outside, into the cavity delimited by the housing 302.
• the wire 306 is traversed by the external current, i ext , to be measured.
• the external current i ext flows in the wire 306, it generates an external magnetic field B ext around the wire 306, in particular inside the housing 302.
• the external field B ext is linear with respect to the external current i ext .
• the external current i ext (t) varies over time t. The same is true of the external magnetic field B ext (t).
• the magnetometric sensor 310 is able to measure the external magnetic field B ext (t) within the housing 302 to indirectly obtain a measurement of the current i ext (t).
• the magnetometric sensor 310 comprises a magnetic sensor 312, a control circuit 314 and a conductive wire 316.
• a magnetic sensor 312 comprises a component sensitive to the magnetic field, which is able to deliver, in the form of a voltage or a current, a measurement signal V corresponding to the magnetic field in which it is immersed.
• Magnetic sensors include optical magnetic sensors, such as NV diamond center sensors, in which the transition between two energetic levels of the electrons of an atom constituting an impurity in a crystal is modified when this crystal is immersed in a crystal. external magnetic field B ext . Changing the transition changes the response of the illuminated crystal to a suitable laser light. Such a magnetic sensor operates at ambient temperature.
• the response of the crystal is linear but over a reduced frequency range around a characteristic frequency of the transition width used.
• superconducting magnetic sensors are also known, which are particularly interesting since they offer the highest sensitivities physically attainable.
• Such a magnetic sensor implementing superconducting materials, operates at low temperatures, around 80 K for the so-called high-temperature or ultra-low-temperature superconducting materials, around the milli-Kelvin approximately for the so-called superconducting materials. low critical temperature.
• a superconducting magnetic sensor is a SQUID component ("Superconducting QUantumInterference Device” in English) or a SQIF component ("Superconducting Quantum Interference Filter” in English).
• An SQIF component consists of a matrix of SQUID components, connected in series, in parallel, or both.
• the SQUID and SQIF components have a non-linear response, that is to say that the voltage ⁇ ( ⁇ ) induced by the flux ⁇ of the external magnetic field B Ext passing through a surface S of the component , is not a linear function of ⁇ 6 ⁇ flow, and therefore the external magnetic field B ext.
• this response is sinusoidal.
• the behavior is, in the first order, linear.
• this region corresponds to a relatively narrow flow range.
• the response of an SQIF component takes the form of an "inverted comb".
• this region the symmetrical response around the origin is quasi-linear.
• this region corresponds to a relatively narrow flow range.
• Magnetic sensor 312 is a superconducting magnetic sensor.
• the magnetic sensor 312 is of rectangular parallelepiped shape. It has a small thickness and an active surface S, substantially flat and having a normal in the direction of the thickness of the magnetic sensor.
• the magnetic sensor 312 is able to generate, between its two output terminals, a response signal, which is here a voltage V.
• the voltage V is a function of the instantaneous total magnetic flux ⁇ ⁇ ) through the surface S.
• the control circuit 314 receives between its two input terminals, E1 and E2, the response signal ⁇ ( ⁇ (3 ⁇ 4) produced by the magnetic sensor 312, and generates a feedback current i CR (t) between its two output terminals, S1 and S2.
• control circuit 314 comprises a comparison means 22 connected to the input terminals E1 and E2, and able to compare the response signal ( ⁇ (3 ⁇ 4) with a reference signal V 0 and to generate a signal of comparison.
• the control circuit 314 comprises a current source 24 controlled by the comparison signal and able to generate, between two output terminals, the counter-current i C R (t).
• the conductive wire 316 is connected between the output terminals S1 and S2 of the control circuit 314. It is shaped to circulate in the vicinity of the magnetic sensor 312.
• the conductive wire 316 is crossed by the counter-current i CR (t).
• i CR (t) the counter-current magnetic field B CR (t).
• the field B CR (t) is linear with respect to the current i C R (t).
• the response signal V (t) delivered by the magnetic sensor 312 depends on the total magnetic flux ⁇ ⁇ ) passing through the surface S.
• the sensor 310 is in equilibrium when the total flux ⁇ ⁇ ) received by the magnetic sensor 312 is constant. In this regime, permanently forced by the instantaneous counter-reaction, the counter-reaction current i C R (t) represents a linear measurement of the external magnetic field B ext (t)
• the geometrical and physical parameters of the sensor 310 are chosen so that the counter-feedback flow is opposed to the external flux and the response V (t) of the magnetic sensor 312 can be instantaneously brought back to the level of the reference voltage V 0.
• the control circuit 314 and the conductive wire 316 are such that a feedback magnetic field is created whose flux through the active surface of the magnetic sensor substantially compensates, at each instant, the flux of the external magnetic field.
• the stabilization point will be the reference voltage V 0 shifted by a constant.
• the maximum sensitivity of the sensor 310 is obtained for the response zone of the magnetic sensor 312 where the derivative ⁇ is maximum.
• this corresponds to the point of inflection of the sinusoidal response.
• this corresponds to the origin point, possibly slightly offset to avoid ambiguities on the sign of the field and therefore on that of the current due to the symmetrical response of such a magnetic sensor.
• the response signal of the magnetic sensor 312 is not considered as a measurement signal, but as a control signal of a feedback loop. It is the feedback signal that constitutes the measurement signal.
• the current detection device has a high sensitivity, a linear behavior and uniform over an extended bandwidth, by constraining the operation of the magnetic sensor in the narrow region where it has a high sensitivity and linear behavior.
• the first and second son 306 and 316 are arranged in the plane P of the surface S magnetic sensor 312.
• FIG. 1 represents an embodiment in which the first and second wires 306 and 316 are rectilinear and arranged on either side of the magnetic sensor 312.
• the detection device 400 has a loop configuration.
• An element of the device of Figure 2 identical or similar to a corresponding element of the device of Figure 1 is identified by the same reference numeral as the corresponding element increased by a hundred.
• the first wire 406 is shaped to form a first loop around the magnetic sensor 412. It then measures a flow ct> ext (t) induced by a current loop, rather than by a rectilinear conductive wire. Assuming a circular loop, a multiplicative factor equal to ⁇ is thus introduced between the rectilinear configuration of FIG. 4 and the loop configuration.
• the second yarn 416 is advantageously also shaped to form a second loop comprising N2 turns.
• This loop configuration has a broadband response.
• the bandwidth is limited at high frequencies mainly by a radiative resistance effect, R rad , which is proportional to f 4 , where f is the frequency of the counter reaction current i CR .
• the radiative resistance dominates here on another limitation which is due to the inductance of the loop formed by the wire 416, this inductance being proportional to f.
• the radiative resistance R rad can be reduced so as to push back to the maximum cutoff frequency of the sensor 410.
• Z is the impedance of the second feedback loop.
• control circuit 414 is then adapted to generate a counter-reaction current such as:
• the feedback current is injected into the second wire so as to flow in the opposite direction to that of the induced current.
• the loop configuration allows dense one or two dimensional integration in the plane P, as schematically shown in FIG.
• This loop configuration allows the realization of a magnetic sensor with reduced dimensions.
• FIG. 3 shows a detection device 500 which constitutes an intermediate embodiment between the devices 300 and 400.
• An element of the device of FIG. 3 identical or similar to a corresponding element of the device of FIG. 1 is identified by the same reference number as this corresponding element increased by two hundred.
• the second wire 516 is straight.
• the advantage here is to allow the elimination of the induced parasitic current i ind (t) in the second wire by the first wire in the device 400.
• the impedance of the magnetometric sensor 510 is thus greatly reduced, while maintaining the significant sensitivity because of the presence of the factor ⁇ . NI of the first loop compared to the configuration where the two wires are straight ( Figure 1).
• An element of the device of Figure 4 identical or similar to a corresponding element of the device of Figure 1 is identified by the same reference numeral as the corresponding element increased by three hundred.
• the magnetic sensor 612 consists of a plurality of elementary magnetic sensors 612-i, which are arranged in a row, so that their respective Si surfaces are in the same plane P.
• the elementary sensors 612 -i are connected in series between the input terminals E1 and E2 of the control circuit 614.
• the first and second wires 606 and 616 are shaped so as to run parallel to each other in the plane P. They are separated from each other by a reduced pitch relative to their respective widths.
• the leads 606 and 616 are configured to flow between two elementary magnetic sensors 612-i forming a meander.
• the external current i ex t (t) is applied in the first wire 606 so as to flow in one direction and the counter-current i CR (t) is applied in the second wire 616 so as to flow in the other direction .
• the magnetic field generated by a wire has, in the plane P of the Si surfaces of the elementary magnetic sensors, an orientation in the normal direction to the plane P, which is positive on one side of the wire and negative on the other side of the wire.
• the meandering configuration introduces a parasitic inductance and radiative resistance, thereby limiting the bandwidth.
• the meander pattern is characterized by inductance and radiative resistance which are intrinsically weaker than that of the loop configuration, thereby further increasing the high cutoff frequency of the current sensing device bandwidth.
• the radiative resistance can be reduced so as to push back to the maximum cutoff frequency of the sensor.
• the distance x between the second wire 616, respectively 716, and the axis of the magnetic sensors 612-i can be increased.
• This meandering configuration allows dense one or two dimensional integration in the plane P, as schematically shown in FIG. 7.
• This meandering configuration allows the realization of a current detection device with reduced dimensions.
• the meandering configuration is also more advantageous than the loop configuration, as it is easier to optimize and integrate on a large scale.
• the current detection device has a wide bandwidth on which, when the magnetic sensor is of the superconducting type, it has a very high sensitivity.
• VLF Very Low Frequency
• UHF Ultra High Frequency
• the current detection device also has an intrinsically linear response with respect to the intensity of the external current to be measured. In addition, this response is uniform over the entire bandwidth, that is to say it is independent of the frequency of the external current to be measured.
• the current detection device can be adapted: segmentation into counter-current currents of the control circuit, optimized dimensioning of the loop circuit / meander of the two conducting wires, multi-scale integration etc.
• low-pass filters may be introduced into the control circuit, to allow a number of frequency utilization ranges to be specified, either in order of magnitude of the external current to be measured, or by frequency domains of interest. .
• the current detection device finally offers the possibility of planar integration high density.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Measuring Magnetic Variables (AREA)
• Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)

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• 2014
  • 2014-05-30 FR FR1401254A patent/FR3021750B1/fr active Active
• 2015
  • 2015-05-29 CN CN201580029067.0A patent/CN106415281A/zh active Pending
  • 2015-05-29 EP EP15725627.2A patent/EP3149505A1/de not_active Withdrawn
  • 2015-05-29 WO PCT/EP2015/062041 patent/WO2015181383A1/fr active Application Filing
  • 2015-05-29 US US15/314,958 patent/US20170192039A1/en not_active Abandoned

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