CN112394216B - Leakage current sensor, leakage current detection circuit, and power supply device - Google Patents

Abstract

The application provides a leakage current sensor, a leakage current detection circuit and power supply equipment, and belongs to the technical field of electronics. According to the leakage current sensor, the magnetic sensing element is arranged in the region of the symmetry axis or the symmetry center of the current leads, so that the leakage current detection function can be realized. And because this leakage current sensor all sets up magnetic sensing element and many electric current wires on the base plate, this planar mode of setting compares and adopts annular magnetic core among the correlation technique to and the mode of setting of electric current wire threading formula, effectively simplified leakage current sensor's structure, reduced leakage current sensor's volume.

Description

Leakage current sensor, leakage current detection circuit, and power supply device

Technical Field

The present application relates to the field of electronic technologies, and in particular, to a leakage current sensor, a leakage current detection circuit, and a power supply device.

Background

Power supply apparatuses such as inverters and Uninterruptible Power Supplies (UPS) can supply a multiphase ac power to electric devices. Normally, the phase difference of each phase alternating current supplied by the power supply device is a fixed value, and the sum of each phase alternating current should be zero. When the phase difference of each phase of alternating current changes, the sum of each phase of alternating current is not zero, namely, leakage current exists in each phase of alternating current, and the normal operation of electric equipment is affected at the moment. Therefore, a leakage current sensor for detecting a leakage current is generally provided in the current power supply device.

In the related art, the leakage current sensor is generally a fluxgate sensor, and the fluxgate sensor includes: the coil comprises a ring-shaped magnetic core, an induction coil wound on the magnetic core, and a plurality of current leads penetrating through the magnetic core. Each current conductor may be connected to one of the phase current outputs in the power supply apparatus. When the phase difference of the current flowing through the current leads changes, the magnetic permeability of the magnetic core changes, so that the induction coil wound on the magnetic core generates induction signals, and the magnitude of the induction signals can reflect the magnitude of leakage current.

However, the magnetic core is annular, and the current conducting wire needs to be arranged in a threading manner, so that the fluxgate sensor is large in size and occupies a large amount of space of power supply equipment.

Disclosure of Invention

The application provides a leakage current sensor, leakage current detection circuitry and power supply unit can solve the great problem of leakage current sensor volume among the correlation technique, and technical scheme is as follows:

in one aspect, a leakage current sensor is provided, including: the magnetic sensor comprises a substrate, one or more magnetic sensing elements and a plurality of mutually insulated current leads, wherein the one or more magnetic sensing elements are positioned on the substrate; the plurality of current wires form an axisymmetric pattern having at least one axis of symmetry on which the one or more magnetic sensing elements are located; alternatively, the plurality of current leads form a centrosymmetric pattern, and the one or more magnetic sensing elements are located in the region of the center of symmetry of the centrosymmetric pattern.

The magnetic sensing element is arranged in the area of the symmetry axis or the symmetry center of the current leads, so that the function of leakage current detection can be realized. And, because all set up magnetic sensing element and many electric current wires on the base plate, this plane setting mode compares in the setting mode of the threading formula among the correlation technique, has effectively simplified the structure of leakage current sensor, has reduced the volume of leakage current sensor.

Alternatively, the axisymmetric pattern may be an unclosed circle, an unclosed polygon, or a pattern formed by two parallel arranged current wires. The polygon may be a regular polygon, and each side of the polygon may be a straight line or an arc line.

Optionally, the leakage current sensor may include: three current leads; the axisymmetric pattern may be a non-closed equilateral triangle formed by the three current conductors. In this implementation, the one or more magnetic sensing elements may be located in the region of the center of an equilateral triangle.

Alternatively, the centrosymmetric pattern may be an unclosed circle, a regular polygon with an even number of unclosed sides, or a pattern formed by two parallel current wires.

Optionally, the leakage current sensor may include: a plurality of magnetic sensing elements; the magnetic sensing elements can be stacked along the direction vertical to the bearing surface of the substrate; alternatively, the plurality of magnetic sensing elements may be symmetrically arranged in the bearing surface of the substrate.

By providing a plurality of magnetic sensor elements, the detection accuracy and reliability of the leakage current sensor can be ensured.

Optionally, each current conducting wire is linear, and the current conducting wires are equal in length and equal in line width. The current lead is designed to be linear, so that the process complexity in forming the current lead on the substrate can be simplified, and the manufacturing cost is reduced.

Optionally, the leakage current sensor may further include: a shielding layer on the substrate; the orthographic projection of the shielding layer on the substrate can be overlapped with the orthographic projection of each current conducting wire on the substrate and the orthographic projection of each magnetic sensing element on the substrate.

By arranging the shielding layer, the shielding of external interference signals can be realized, and the detection precision of the magnetic sensing element is ensured.

Optionally, an orthographic projection of the shielding layer on the substrate may cover an orthographic projection of each magnetic sensing element on the substrate. Therefore, the interference of the external interference signal to the magnetic sensing element can be effectively shielded.

Optionally, the leakage current sensor includes: two shielding layers; one shielding layer is positioned on one side of the one or more magnetic sensing elements and the current lead wire far away from the substrate, and the other shielding layer is positioned on one side of the substrate far away from the one or more magnetic sensing elements and the current lead wire. Thereby, the shielding effect of the shielding layer can be effectively ensured.

Optionally, the material of the shielding layer is a soft magnetic material. The shielding layer made of the soft magnetic material can shield external interference signals and amplify a magnetic field, so that the magnetic field generated by weak leakage current can be detected by the magnetic sensing element, and the detection precision of the magnetic sensing element is effectively improved.

Optionally, the substrate includes a first sub-substrate and a second sub-substrate stacked, and the current conducting wire is located on the first sub-substrate; the leakage current sensor further includes: a power supply wire and a signal wire on the second sub-substrate; through holes are formed in the first sub-substrate, and each magnetic sensing element is positioned on the first sub-substrate and penetrates through the through holes to be respectively connected with the power supply lead and the signal lead; the power supply wire is also used for connecting a power supply, and the signal wire is also used for connecting a signal processing sub-circuit.

By adopting the two sub-substrates, the different-layer arrangement of the current lead, the power lead and the signal lead can be realized, the interference of the power lead and the signal lead to the current lead is avoided, and the detection precision of the magnetic sensing element is ensured.

Optionally, the leakage current sensor may further include: wire leads disposed at the edge of the substrate; each end of each current conductor may be connected to a respective conductor pin. By providing the lead pin, it is possible to facilitate connection of the current lead to an external circuit.

The current lead can be a copper wire, and the lead pins can be made of a soldering material.

Optionally, the magnetic sensing element comprises: a hall element, a transformer element, an anisotropic magnetoresistive element, a giant magnetoresistive element, or a magnetic tunnel junction element; the substrate is made of organic material or ceramic material.

In another aspect, a leakage current detection circuit is provided, which may include: a leakage current sensor as provided in the above aspect, and a signal processing sub-circuit; the signal processing sub-circuit is connected with the magnetic sensing element in the leakage current sensor and is used for detecting whether leakage current exists in a plurality of current wires in the leakage current sensor according to the sensing signal transmitted by the magnetic sensing element.

In yet another aspect, there is provided a power supply apparatus, which may include: the leakage current detection circuit provided in the above aspect, and the power supply circuit; the current output end of the power supply circuit is connected with a current lead in a leakage current sensor included in the leakage current detection circuit.

In summary, embodiments of the present invention provide a leakage current sensor, a leakage current detection circuit, and a power supply device, in which a magnetic sensing element is disposed in a region where a symmetry axis or a symmetry center of a plurality of current wires is located, so that a leakage current detection function can be implemented. And because this leakage current sensor all sets up magnetic sensing element and many electric current wires on the base plate, this planar mode of setting compares and adopts annular magnetic core among the correlation technique to and the mode of setting of electric current wire threading formula, effectively simplified leakage current sensor's structure, reduced leakage current sensor's volume.

Drawings

Fig. 1 is a schematic structural diagram of a leakage current sensor according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a leakage current sensor in the AA direction according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another leakage current sensor provided in the embodiment of the present invention;

fig. 4 is a schematic structural diagram of another leakage current sensor provided in the embodiment of the present invention;

fig. 5 is a schematic structural diagram of another leakage current sensor according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of another leakage current sensor according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of another leakage current sensor according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a leakage current sensor according to another embodiment of the present invention;

fig. 9 is a schematic structural diagram of a leakage current sensor according to another embodiment of the present invention;

fig. 10 is a schematic structural diagram of a leakage current sensor according to another embodiment of the present invention;

FIG. 11 is a cross-sectional view of another leakage current sensor provided in accordance with an embodiment of the present invention in the AA direction;

FIG. 12 is a cross-sectional view of yet another leakage current sensor provided by an embodiment of the present invention in the AA direction;

fig. 13 is a schematic structural diagram of a leakage current sensor according to another embodiment of the present invention;

fig. 14 is a cross-sectional view of a leakage current sensor provided in an embodiment of the present invention, in the BB direction;

fig. 15 is a schematic structural diagram of a leakage current sensor according to another embodiment of the present invention;

fig. 16 is a schematic structural diagram of a leakage current detection circuit according to an embodiment of the present invention;

fig. 17 is a schematic structural diagram of a power supply device according to an embodiment of the present invention.

Detailed Description

In the related art, in order to ensure the magnetic field sensitivity of the magnetic core in the fluxgate sensor, the magnetic core is generally made of a nanocrystalline material, which is expensive, resulting in high material cost of the fluxgate sensor. In addition, in order to achieve high detection accuracy, the number of turns of the induction coil in the fluxgate sensor is generally high, which results in a complicated manufacturing process and high manufacturing cost of the fluxgate sensor.

The embodiment of the invention provides a leakage current sensor, which can solve the problem that a fluxgate sensor in the related art is large in size and the problems that the fluxgate sensor body is high in material cost and manufacturing cost.

Fig. 1 is a schematic structural diagram of a leakage current sensor according to an embodiment of the present invention, and fig. 2 is a cross-sectional view of fig. 1 in the direction AA. As shown in fig. 1 and 2, the leakage current sensor may include: the magnetic sensor comprises a substrate 01, one or more magnetic sensing elements 02 positioned on the substrate 01, and a plurality of mutually insulated current conducting wires 03 positioned on the substrate 01. For example, one magnetic sensing element 02 and two current leads 03 are shown in fig. 1 and 2. Wherein, a plurality means two or more, and a plurality means two or more.

In the embodiment of the present invention, the plurality of current wires 03 may form an axisymmetric pattern having at least one symmetry axis, i.e., one or more symmetry axes. At least two of the plurality of current wires 03 may be located on both sides of one of the symmetry axes m, and the one or more magnetic sensing elements 02 may be located on the one symmetry axis m. For example, the plurality of magnetic sensor elements 02 may be arranged at equal intervals on the symmetry axis m.

Alternatively, the plurality of current wires 03 may form a center symmetrical pattern. The one or more magnetic sensing elements 02 may then be located in the region of the center of symmetry of the central symmetry pattern, i.e. the point where the center of symmetry is located. For example, the orthographic projection of each magnetic sensor element 02 on the substrate 01 may cover the orthographic projection of the center of symmetry on the substrate 01.

The axisymmetric figure is a figure in which the parts at both sides of a straight line can be completely superposed after being folded along the straight line in a plane, and the straight line is the symmetric axis of the axisymmetric figure. The centrosymmetric figure is a figure which can be superposed with an original figure after being rotated by 180 degrees around a certain point in a plane, and the point is the symmetric center of the centrosymmetric figure.

When the leakage current sensor is used for detecting leakage current, each current conducting wire 03 in the leakage current sensor can be connected with one phase current output end in the multi-phase current output end of the circuit to be detected. If the phase difference of the alternating currents of the phases output by the circuit to be detected is fixed, that is, no leakage current exists in the alternating currents of the phases, the magnetic fields generated by the current wires 03 in the region where the symmetry axis or the symmetry center is located can be mutually cancelled, that is, the magnetic field strength in the region where the symmetry axis or the symmetry center is located is close to 0 oersted (Oe). If leakage current exists in each phase of alternating current output by the circuit to be detected, the magnetic fields generated by the current leads 03 in the region where the symmetry axis or the symmetry center is located cannot be completely offset, the magnetic sensing element 02 located in the region where the symmetry axis or the symmetry center is located can detect the magnetic fields, and can convert detected magnetic field signals into induction signals and output the induction signals. The sensing signal may be a voltage signal or a current signal. The magnitude of the induction signal can reflect the magnitude of the magnetic field intensity of the region where the symmetry axis or the symmetry center is located, and further can reflect the magnitude of leakage current in the multi-phase alternating current output by the circuit to be detected.

In summary, embodiments of the present invention provide a leakage current sensor, in which a magnetic sensing element is disposed on a symmetry axis or a region where a symmetry center of a plurality of current wires is located, so that a leakage current detection function can be implemented. And because this leakage current sensor all sets up magnetic sensing element and many electric current wires on the base plate, compare and adopt annular magnetic core among the correlation technique to and the mode of setting of electric current wire threading formula, this plane mode of setting has effectively simplified leakage current sensor's structure, has reduced leakage current sensor's volume.

In addition, in the leakage current sensor provided by the embodiment of the invention, the magnetic sensing element and the current lead can be formed on the substrate by adopting the traditional printing process, and the manufacturing process is simpler and the manufacturing cost is lower. And because the cost of the magnetic sensing element is lower, the material cost of the leakage current sensor is effectively reduced.

In the embodiment of the present invention, the substrate 01 may be a Printed Circuit Board (PCB), and the material thereof may be an organic material or a ceramic material, or may also be an inorganic material other than a ceramic material. The magnetic sensor element 02 may be an Integrated Circuit (IC), which has a small volume and is convenient to be disposed on a substrate, and thus the volume of the leakage current sensor can be effectively reduced.

Alternatively, the magnetic sensing element 02 may include: hall elements, mutual inductor elements, anisotropic magnetoresistive elements, giant magnetoresistive elements, magnetic tunnel junction elements, or the like. The magnetic tunnel junction element may be a Tunneling Magneto Resistance (TMR) sensor. The TMR sensor has high sensitivity, and can realize detection of a magnetic field with a nanometer Tesla (nT) magnitude, thereby realizing detection of weak leakage current.

It should be noted that, in the embodiment of the present invention, the plurality of current wires 03 have the same shape, the same length, and the same line width. For example, referring to fig. 1, each current conducting wire 03 may be linear, and designing the current conducting wire 03 to be linear can simplify the process complexity when forming the current conducting wire 03 on the substrate 01 and reduce the manufacturing cost. Alternatively, referring to fig. 3, each current conductor 04 may be of an arc type. Wherein, for an arc-type current conductor, the length of the current conductor may refer to the arc length.

Due to the limitation of the precision of the manufacturing process, there may be some errors in the shape, length, and line width of the current conducting line 03. In the embodiment of the present invention, the shape of the plurality of current wires 03 being the same may mean that an error between the shape of each current wire 03 and the fixed shape is within a certain error range. The equal length of the current wires 03 may mean that the length of each current wire 03 is within a certain error range from the length of the fixed length. The equal line widths of the plurality of current conducting lines 03 may mean that the line width error between the line width of each current conducting line 03 and the fixed line width is within a certain error range. In addition, the error ranges of the length error and the width error of the current lead 03 can be set according to the requirement for the detection accuracy of the leakage current sensor. For example, the error range of the length error of the current conducting wire 03 can be: not more than 10% or 30% of the fixed length, the error range of the width error may be: not greater than 10% or 30% of the fixed width.

In the embodiment of the present invention, for a scenario where the plurality of current wires 03 form an axisymmetric pattern, as an alternative implementation manner, each current wire 03 may be in an arc shape, and the axisymmetric pattern may be a non-closed circle formed by the plurality of current wires.

For example, referring to fig. 3, the leakage current sensor may include two current wires 03, and the axisymmetric pattern may be a non-closed circle formed by the two current wires 03. Alternatively, referring to fig. 4, the leakage current sensor may include three current wires 03, and the axisymmetric pattern may be a non-closed circle formed by the three current wires 03.

As another alternative implementation, the axisymmetric pattern may be an unclosed polygon formed by the plurality of current wires. The polygon may be a regular polygon or may be a diamond. Each side of the polygon may be a straight line or an arc. Also, each side of the polygon may be formed by one current conductor, or may be formed by a plurality of spaced and collinear current conductors. Wherein the plurality of spaced and collinear current leads may be connected to the same phase current output.

For example, referring to fig. 5, the leakage current sensor may include three current wires 03 in a straight line shape, and the axisymmetric pattern may be a non-closed equilateral triangle (i.e., a regular triangle) formed by the three current wires 03. Alternatively, referring to fig. 6, the leakage current sensor may include three current wires 03 in an arc shape, and the axisymmetric pattern may be a non-closed arc triangle (also called a reuleaux triangle or an arc triangle) formed by the three current wires 03. Still alternatively, referring to fig. 7 and 8, the leakage current sensor may include four current wires 03 having a straight line shape, and the axisymmetric pattern may be a non-closed diamond shape as shown in fig. 7 or a non-closed square shape as shown in fig. 8 formed by the four current wires 03.

As yet another alternative implementation, as shown in fig. 1, the axisymmetric pattern may be a pattern formed by two current wires 03 arranged in parallel. That is, the leakage current sensor may include two current wires 03 arranged in a linear, axisymmetric, and parallel manner.

Alternatively, referring to fig. 9, the leakage current sensor may include two current wires 03 in a straight line shape, which are not parallel, that is, the extending directions of the two current wires 03 may intersect.

For the scenario where the plurality of current wires 03 form a central symmetrical pattern, referring to fig. 3 and 4, the central symmetrical pattern may be a non-closed circle. Alternatively, referring to fig. 8, the central symmetrical pattern may be a regular polygon having an even number of non-closed sides. Alternatively, as shown in fig. 10, the central symmetrical pattern may be a pattern formed by two parallel current leads 03, and as shown in fig. 10, the central symmetrical pattern is not an axisymmetric pattern.

It should be noted that, in the embodiment of the present invention, the number of the current wires 03 disposed in the leakage current sensor may be flexibly designed according to the number of phases of the multi-phase alternating current output by the circuit to be detected to which the leakage current sensor is applied, that is, the number of the current wires 03 may be equal to the number of phases of the alternating current output by the circuit to be detected. The above description has been given by taking two current leads, three current leads and four current leads as examples. When the number of phases of the alternating current output by the circuit to be detected is N, and N is an integer greater than 4, the number of the current wires 03 arranged in the leakage current sensor may also be N. And, the N current wires 03 may enclose an unclosed regular N-polygon or a circle. For example, when N is 5, the N current leads 03 may enclose a non-closed regular pentagon.

In an embodiment of the present invention, the leakage current sensor may comprise one or more magnetic sensing elements 02. When the leakage current sensor includes only one magnetic sensing element 02, it can be ensured that the leakage current sensor is low in cost. When the leakage current sensor includes the plurality of magnetic sensing elements 02, the reliability and detection accuracy of the leakage current sensor can be effectively improved.

In the embodiment where the leakage current sensor includes a plurality of magnetic sensor elements 02, as shown in fig. 11, the plurality of magnetic sensor elements 02 may be stacked in a direction perpendicular to the carrying surface of the substrate 01. Alternatively, as shown in fig. 3 and 8, the plurality of magnetic sensing elements 02 may be symmetrically arranged in the bearing surface of the substrate 01. For example, for a scheme in which the plurality of current wires 03 form an axisymmetric pattern, referring to fig. 3, the plurality of magnetic sensor elements 02 may be symmetrically arranged on the symmetry axis m. The plurality of magnetic sensing elements 02 may be symmetrically arranged with respect to a point on the symmetry axis m that is equidistant from or close to (e.g., closest to) the end points of the current lines. For the scheme in which the plurality of current wires 03 form a center symmetrical pattern, referring to fig. 8, the plurality of magnetic sensor elements 02 may be symmetrically arranged with the center of symmetry o as a point of symmetry.

When only one magnetic sensor element 02 is included in the leakage current sensor, or when a plurality of magnetic sensor elements 02 are stacked, for a scheme in which the plurality of current wires 03 form an axisymmetric pattern, if the axisymmetric pattern includes only one symmetry axis, the magnetic sensor element 02 or the plurality of magnetic sensor elements 02 stacked may be located in a region where any point on the symmetry axis is located. In order to improve the detection accuracy, the single magnetic sensor element 02 or the plurality of magnetic sensor elements 02 stacked in layers may be located in a region where a point on the symmetry axis is located at a same distance or a close distance (for example, the closest distance) to the end point of each current lead 03. For example, for the scheme shown in fig. 9, the magnetic sensing element 02 or the plurality of magnetic sensing elements 02 stacked in layers may be located in a region where a midpoint of a bisector of a vertex angle of an isosceles triangle formed by the two current wires 03 as a waist is located. The midpoint is a point that divides a line segment into two equal line segments.

In the case where the plurality of current wires 03 form an axisymmetrical pattern, if the axisymmetrical pattern includes a plurality of symmetry axes, the one magnetic sensor element 02 or the plurality of magnetic sensor elements 02 stacked one on another can be located in a region where an intersection of the plurality of symmetry axes is located, whereby the detection accuracy of the leakage current sensor can be further ensured.

Fig. 12 is a further cross-sectional view in the AA direction of fig. 1, and as shown in fig. 12, the leakage current sensor may further include: one or more shielding layers 04 on the substrate 01. For example, two shielding layers 04 are shown in fig. 12. The orthographic projection of the shielding layer 04 on the substrate 01 can be overlapped with the orthographic projection of the current lead 03 on the substrate 01 and the orthographic projection of each magnetic sensing element 02 on the substrate 01. The shielding layer 04 can shield external interference signals, thereby ensuring the detection accuracy of the magnetic sensing element 03.

Alternatively, the material forming the shielding layer 04 may be a soft magnetic material, and the soft magnetic material may include one or more of ferrite, a metal powder core, an amorphous material, and a nanocrystalline material. Wherein, the ferrite can be manganese zinc ferrite. The shielding layer 04 formed by the soft magnetic material not only can play a role in shielding external interference signals, but also can play a role in amplifying a magnetic field, namely the shielding layer 04 has the functions of magnetism gathering and shielding. Therefore, even a magnetic field generated by a weak leakage current can be detected by the magnetic sensor element 03, and the detection accuracy of the magnetic sensor element 03 is effectively improved.

In the embodiment of the present invention, in order to ensure the magnetism gathering and shielding effects of the shielding layers 04, the orthographic projection of each shielding layer 04 on the substrate 01 may be covered on the orthographic projection of each magnetic sensing element 02 on the substrate 01. That is, the orthographic projection of each magnetic sensing element 02 on the substrate 01 can be located within the orthographic projection of the shielding layer 04 on the substrate 01. And the orthographic projection of each shielding layer 04 on the substrate 01 can cover part or all of the orthographic projection of each current lead 03 on the substrate 01. For example, in order to effectively improve the magnetic gathering and shielding effects of the shielding layer 04, the orthographic projection of each current conducting wire 03 on the substrate 01 may also be located within the orthographic projection of the shielding layer 04 on the substrate 01.

Alternatively, referring to fig. 12, the leakage current sensor may include: two shielding layers 04. One of the shielding layers 04 may be located on a side of the one or more magnetic sensing elements 02 and the current lead 03 away from the substrate 01, and the other shielding layer 04 may be located on a side of the substrate 01 away from the one or more magnetic sensing elements 02 and the current lead 03.

By arranging the one or more magnetic sensing elements 02 and the current conducting wire 03 between the two shielding layers 04, effective amplification of a magnetic field generated by leakage current and effective shielding of external interference signals can be ensured, thereby further ensuring the detection accuracy of the magnetic sensing element 03.

Fig. 13 is a schematic structural diagram of another leakage current sensor according to an embodiment of the present invention, and as shown in fig. 13, the substrate 01 may be a multilayer substrate, which may include a first sub-substrate 011 and a second sub-substrate 012 that are stacked. The current wire 03 may be located on the first submount 011. The leakage current sensor may further include: a power supply wire 05 and a signal wire 06 on the second sub-substrate 012.

A via hole (not shown) is provided in the first sub-substrate 011, and each magnetic sensor element 02 may be located on the first sub-substrate 011 and may be connected to the power supply wire 05 and the signal wire 06 through the via hole, respectively. The power wire 05 can also be used to connect a power supply, and the power supply can supply power to the magnetic sensing element 02 through the power wire 05. The signal conductor 06 can also be used for connecting a signal processing sub-circuit, through which the magnetic sensor element 02 can transmit the sensing signal to the signal processing sub-circuit, so that the signal processing sub-circuit can determine whether there is a leakage current according to the sensing signal.

By adopting the two sub-substrates, the current lead 03, the power lead 05 and the signal lead 06 can be arranged in different layers, the interference of the power lead 05 and the signal lead 06 on the current lead 03 is avoided, and the detection precision of the magnetic sensing element 03 is ensured.

Note that, when the leakage current sensor includes a plurality of magnetic sensor elements 02 arranged in a stacked manner, referring to fig. 11, the leakage current sensor may include a plurality of first sub-substrates 011 arranged in a stacked manner, and each of the magnetic sensor elements 02 may be disposed on one of the first sub-substrates 011.

Note that the substrate 01 may include a sub-substrate other than the first sub-substrate 011 and the second sub-substrate 012. The first sub-substrate 011 and the second sub-substrate 012 can be two adjacent sub-substrates in the substrate 01 or two non-adjacent sub-substrates, which is not limited in the embodiments of the present invention.

Alternatively, fig. 14 is a cross-sectional view of fig. 1 in the BB direction, and as shown in fig. 14, the leakage current sensor may further include: and a wire lead 07 disposed at an edge of the substrate 01. Each end of each current conductor 03 can be connected to a respective conductor pin 07. That is, the end of the current line 03 can be connected to the line pin 07, and the current line 03 can be connected to the current output of the circuit to be tested via this line pin 07.

For example, referring to fig. 14, the current lead 03 and the lead pin 07 may be located on different sides of the substrate 01, and the current lead 03 may be connected to the lead pin 07 through a via hole on the substrate 01. Of course, the current lead 03 and the lead pin 07 may be located on the same side of the substrate 01, and in this case, the current lead 03 may be directly connected to the lead pin 07.

It should be noted that, in the embodiment of the present invention, the current lead 03, the power lead 05, the signal lead 06, and the lead pin 07 may be made of metal materials. For example, each of the leads may be made of copper, and the lead pins 07 may be made of a solder material.

It should be noted that the end of the power supply lead 05 away from the magnetic sensor element 02 and the end of the signal lead 06 away from the magnetic sensor element 02 may also be connected to one lead pin 07, respectively. That is, a lead pin 07 connected to the current lead 03, a lead pin 07 connected to the power supply lead 05, and a lead pin 07 connected to the signal lead 06 may be provided at an edge of the substrate 01.

In the embodiment of the present invention, as shown in fig. 12 and 14, the leakage current sensor may further include a housing 08, and the substrate 01, and various elements disposed on the substrate 01 may be all encapsulated in the housing 08. Alternatively, the housing 08 may be made of plastic.

As can also be seen with reference to fig. 14, the leakage current sensor may further include a plurality of connection lines 09, each connection line 09 having one end located inside the housing 08 and connected to one of the lead pins 07 and the other end located outside the housing 08 for connection to an external circuit. The connecting wire 09 may be a metal wire, such as a copper wire.

In the embodiment of the present invention, if a certain wire pin 07 is connected to the current wire 03, the other end of the connection line 09 connected to the wire pin 07 may be connected to the current output terminal of the circuit to be detected. If a lead pin 07 is connected to the power supply lead 05, the other end of the connection wire 09 connected to the lead pin 07 may be connected to a power supply source. If a lead pin 07 is connected to the signal lead 05, the other end of the connection line 09 connected to the lead pin 07 may be connected to the signal processing sub-circuit.

The following describes a method for using the leakage current sensor according to the embodiment of the present invention, by taking the leakage current sensor including two current wires and three current wires as an example.

On one hand, if the leakage current sensor includes two current wires 03, the circuit to be detected applied by the leakage current sensor may be a power supply device that provides a two-phase alternating current with a phase difference of 180 degrees, that is, the leakage current sensor may detect leakage current in the two-phase alternating current. When the leakage current sensor is used for detecting leakage current, each current conducting wire can be respectively connected with one-phase current output end of the power supply equipment. In addition, when connecting, as shown in fig. 3, 9, 10, and 13, the directions of the currents flowing through the two current wires 03 need to be opposite.

Since the directions of the currents flowing through the two current wires 03 are opposite, it is ensured that the magnetic fields generated by the two current wires 03 in the region of the symmetry axis m or the symmetry center thereof cancel each other when the phase difference between the currents flowing through the two current wires 03 is 180 degrees. Therefore, when the phase difference between the currents flowing through the two current wires 03 changes, that is, when there is a leakage current, the magnetic fields generated by the two current wires 03 in the region where the symmetry axis m or the symmetry center is located cannot be completely cancelled, and the magnetic sensing element 02 can detect the change in the magnetic fields and output an induction signal.

On the other hand, if the leakage current sensor includes three current wires 03, the circuit to be detected to which the leakage current sensor is applied may be a power supply device that provides three-phase alternating current with a phase difference of 120 degrees, that is, the leakage current sensor may detect leakage current in the three-phase alternating current. When the leakage current sensor is used for detecting leakage current, each current conducting wire can be respectively connected with one-phase current output end of the power supply equipment. In addition, during connection, as shown in fig. 4 to 6, the directions of the currents flowing through the three current wires 03 need to be arranged clockwise or counterclockwise, and the phase difference between the currents flowing through every two adjacent current wires 03 is 120 degrees.

Because the directions of the currents flowing through the three current leads 03 are arranged clockwise or counterclockwise, it can be ensured that when the phase difference of the currents flowing through each two adjacent current leads 03 is 120 degrees, the magnetic fields generated by the three current leads 03 in the region where the symmetry center is located can be mutually offset. Therefore, when the phase difference of the currents flowing through the three current wires 03 changes, that is, when there is a leakage current, the magnetic fields generated by the three current wires 03 in the region where the symmetry center is located cannot be completely cancelled, and the magnetic sensing element 02 can detect the change of the magnetic fields and output an induction signal.

It should be noted that the leakage current sensor provided in the embodiment of the present invention may be used to detect leakage current in multi-phase ac power, and may also be used to detect dc power, that is, may be used to detect whether current values of multiple paths of dc power are equal.

For example, if the leakage current sensor includes two current wires 03, the leakage current sensor can be used to detect whether the current values of two direct currents are equal. When the leakage current sensor is used for detection, each current lead can be respectively connected with one direct current output end. In the connection, as shown in fig. 15, the directions of the currents flowing through the two current wires 03 need to be the same. Since the directions of the currents flowing through the two current wires 03 are the same, it is ensured that the magnetic fields generated by the two current wires 03 in the region of the symmetry axis m or the symmetry center thereof cancel each other when the current values of the currents flowing through the two current wires 03 are equal. Therefore, when the current values of the currents flowing through the two current wires 03 are not equal, the magnetic fields generated by the two current wires 03 in the region where the symmetry axis m is located cannot be completely cancelled, and the magnetic sensing element 02 can detect the change of the magnetic fields and output the induction signal.

If the leakage current sensor includes three current wires 03, the leakage current sensor may be configured to detect whether the current values of the three direct currents are equal to each other. When the leakage current sensor is used for detection, each current conducting wire can be respectively connected with one direct current output end. In addition, when connecting, referring to fig. 4 to 6, the directions of the currents flowing through the three current wires 03 need to be arranged clockwise or counterclockwise. Because the directions of the currents flowing through the three current leads 03 are arranged clockwise or counterclockwise, it can be ensured that the magnetic fields generated by the three current leads 03 in the regions where the centers of symmetry of the three current leads 03 are located can cancel each other when the current values of the currents flowing through the current leads 03 are equal. Therefore, when the current values of the currents flowing through the three current wires 03 are not equal, the magnetic fields generated by the three current wires 03 in the region where the symmetry center is located cannot be completely cancelled, and the magnetic sensing element 02 can detect the change of the magnetic fields and output the sensing signal.

In summary, embodiments of the present invention provide a leakage current sensor, in which a magnetic sensing element is disposed in a region where a symmetry axis or a symmetry center of a plurality of current wires is located, so that a leakage current detection function can be implemented. In addition, because the magnetic sensing element and the current conducting wires are arranged on the substrate, compared with the structure which adopts an annular magnetic core and a current conducting wire threading type arrangement mode in the related technology, the structure of the leakage current sensor is effectively simplified, and the volume of the leakage current sensor is reduced. For example, the size of the fluxgate sensor in the related art is generally 70 millimeters (mm) × 50mm × 40mm, but the leakage current sensor provided by the embodiment of the present invention may be reduced to 40mm × 40mm × 20mm due to the planar circuit structure, thereby effectively reducing the occupied space in the power supply device.

In addition, the magnetic sensing element and the current lead can be formed on the substrate by adopting the traditional printing process, the manufacturing process is simpler, the manufacturing cost is lower, the manufacturing efficiency can be effectively improved, the consistency of products is improved, and the product quality is more reliable. In addition, the cost of the magnetic sensing element is low, so that the material cost of the leakage current sensor is effectively reduced.

An embodiment of the present invention further provides a leakage current detection circuit, as shown in fig. 16, the circuit may include: a leakage current sensor 10 as provided in the above embodiments, and a signal processing sub-circuit 20.

The signal processing sub-circuit 20 may be connected to the magnetic sensing element 02 of the leakage current sensor 10, and is configured to detect whether a leakage current exists in the plurality of current wires 03 of the leakage current sensor 10 according to the sensing signal transmitted by the magnetic sensing element 02.

Alternatively, the signal processing sub-circuit 20 may store a signal value range in advance, and when the signal processing sub-circuit 20 detects that the signal value of the sensing signal transmitted by the magnetic sensing element 02 is not within the signal value range, it may be determined that the leakage current exists.

In the embodiment of the present invention, the signal processing sub-circuit 20 may be implemented by an application-specific integrated circuit (ASIC), or a Programmable Logic Device (PLD), which may be a Complex Programmable Logic Device (CPLD), a field-programmable gate array (FPGA), a General Array Logic (GAL), or any combination thereof.

An embodiment of the present invention further provides a power supply device, as shown in fig. 17, where the power supply device may include: the leakage current detection circuit 100 and the power supply circuit 200 provided in the above embodiments are described.

Wherein, the current output terminal of the power supply circuit 200 can be connected with the current wire of the leakage current sensor 10 included in the leakage current detection circuit 100.

Optionally, as shown in fig. 17, the power supply apparatus may further include a control circuit 300 connected to the power supply circuit 200. The signal processing sub-circuit 20 in the leakage current detection circuit 100 may be connected to the control circuit 300. The signal processing sub-circuit 20 may send a leakage current prompting signal to the control circuit 300 when detecting the leakage current, and the control circuit 300 may control the power supply circuit 200 to adjust the phase difference of the alternating currents of the phases output by the power supply circuit 200 in response to the leakage current prompting signal, or directly control the power supply circuit 200 to stop operating.

In the embodiment of the present invention, the control circuit 300 may also be implemented by ASIC or PLD. The power supply apparatus may be an inverter or a UPS or the like.

The above description is only exemplary of the present application and should not be taken as limiting, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (14)

1. A leakage current sensor, comprising: the magnetic sensor comprises a substrate, one or more magnetic sensing elements and a plurality of mutually insulated current leads, wherein the one or more magnetic sensing elements are positioned on the substrate;

the plurality of current leads form an axisymmetric pattern, the axisymmetric pattern has at least one symmetry axis, at least two current leads of the plurality of current leads are positioned on two sides of one of the symmetry axes, and one or more magnetic sensing elements are positioned on the one symmetry axis;

or, a plurality of current leads form a central symmetrical pattern, and one or more magnetic sensing elements are positioned in the area of the symmetrical center of the central symmetrical pattern.

2. The leakage current sensor of claim 1, wherein the axisymmetric pattern is an unclosed circle, an unclosed polygon, or a pattern formed by two parallel arranged current wires.

3. The leakage current sensor according to claim 2, wherein the leakage current sensor comprises: the axisymmetric figure of the three current leads is a non-closed equilateral triangle.

4. The leakage current sensor of claim 1, wherein the centrosymmetric pattern is an unsealed circle, an unsealed regular polygon having an even number of sides, or a pattern formed by two parallel arranged current wires.

5. The leakage current sensor according to any one of claims 1 to 4, wherein the leakage current sensor comprises: a plurality of said magnetic sensing elements;

the magnetic sensing elements are stacked along a direction perpendicular to the bearing surface of the substrate;

or the magnetic sensing elements are symmetrically arranged in the bearing surface of the substrate.

6. A leakage current sensor according to any one of claims 1 to 4, wherein each of said current conducting lines is linear, and a plurality of said current conducting lines are equal in length and equal in line width.

7. The leakage current sensor according to any one of claims 1 to 4, further comprising: a shielding layer on the substrate;

the orthographic projection of the shielding layer on the substrate is overlapped with the orthographic projection of each current conducting wire on the substrate and the orthographic projection of each magnetic sensing element on the substrate.

8. The leakage current sensor of claim 7, wherein an orthographic projection of the shielding layer on the substrate covers an orthographic projection of each of the magnetic sensing elements on the substrate.

9. The leakage current sensor according to claim 7, wherein the leakage current sensor comprises: two layers of the shielding layer;

one layer of the shielding layer is positioned on one side of the one or more magnetic sensing elements and the current lead wire far away from the substrate, and the other layer of the shielding layer is positioned on one side of the substrate far away from the one or more magnetic sensing elements and the current lead wire.

10. The leakage current sensor of claim 7, wherein the material of the shielding layer is a soft magnetic material.

11. A leakage current sensor according to any of claims 1 to 4, wherein said substrate comprises a first sub-substrate and a second sub-substrate stacked, said current conductor being located on said first sub-substrate;

the leakage current sensor further includes: a power supply wire and a signal wire on the second sub-substrate;

through holes are formed in the first sub-substrate, and each magnetic sensing element is located on the first sub-substrate and penetrates through the through hole to be connected with the power supply lead and the signal lead respectively;

the power supply wire is also used for connecting a power supply, and the signal wire is also used for connecting a signal processing sub-circuit.

12. The leakage current sensor according to any one of claims 1 to 4, further comprising: wire leads disposed at an edge of the substrate;

each end of each current lead is connected with one lead pin.

13. A leakage current detection circuit, the circuit comprising: a leakage current sensor according to any one of claims 1 to 12, and a signal processing sub-circuit;

the signal processing sub-circuit is connected with a magnetic sensing element in the leakage current sensor and is used for detecting whether leakage current exists in a plurality of current wires in the leakage current sensor according to an induction signal transmitted by the magnetic sensing element.

14. A power supply device characterized by comprising: the leakage current detection circuit of claim 13, and a power supply circuit;

and the current output end of the power supply circuit is connected with a current lead in a leakage current sensor included in the leakage current detection circuit.

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