Leakage current sensor and electronic equipment

Abstract

The invention relates to the technical field of leakage current measurement, and discloses a leakage current sensor and electronic equipment. The leakage current sensor comprises a magnetism gathering ring which is provided with an opening air gap; the first current collector and the second current collector respectively penetrate through the first inner cavity of the magnetism gathering ring, are coupled with the wire to be measured in series and have opposite current directions; a second through curved surface and a second through tangent plane in the second current collector define a second structure in the shape of a semicircular tube; and the magnetic resistance element is positioned in the opening air gap and is close to the center of the first current collector and the second current collector. A first through curved surface and a first through tangent plane in the first current collector define a semicircular tube type first structure; and the second through curved surface and the second through tangent plane in the second current collector define a semicircular tube type first structure. According to the invention, by adjusting the current collector structure and the position of the magnetoresistive element, leakage current measurement of the to-be-measured wire is realized, and the accuracy of leakage current measurement is improved; and the device has the beneficial effects of simple structure and easiness in realization.

Description

Technical Field

[0001] The present invention relates to the technical field of leakage current measurement, and in particular to a leakage current sensor and electronic equipment. Background Art

[0002] In the fields of new energy grid connection, new energy vehicles and safety monitoring, the requirements for single-phase leakage current detection are gradually increasing. Traditional transformers, Hall sensors, fluxgate sensors, etc., when used for leakage current detection, generally have problems such as high cost, poor accuracy, and large size.

[0003] Using magnetoresistance for leakage current detection has become a new focus. The common-mode interference generated by the current of a conventional straight wire will affect the measurement precision and accuracy of the magnetoresistance leakage current sensor, and may even make leakage current detection impossible. Summary of the invention

[0004] The purpose of the present invention is to provide a leakage current sensor and electronic equipment, which are used to improve the problem that the existing leakage current sensor is affected by common mode interference and cannot accurately measure the leakage current.

[0005] A first aspect of the present invention provides a leakage current sensor.

[0006] The leakage current sensor comprises: A magnetic concentrating ring having an open air gap, used for concentrating the magnetic flux of the first inner cavity surrounded by the magnetic concentrating ring to the open air gap; The first current collector and the second current collector of the same structure respectively penetrate the first inner cavity and are respectively coupled in series with the wire to be tested, and have opposite current directions; the first through-curved surface and the first through-cut surface of the first current collector form a first semicircular tube-shaped structure; the second through-curved surface and the second through-cut surface of the second current collector form a second semicircular tube-shaped structure; the center of the first inner cavity is located at the center position of the first structure and the second structure; The magnetoresistive element is located in the open air gap near the center of the first current collector and the second current collector, and is used to sense the current condition of the conductor to be tested.

[0007] According to some embodiments of the present invention, the cross-sections of the first through curved surface and the second through curved surface are semicircles.

[0008] According to some embodiments of the present invention, a cross section of the first through curved surface and the second through curved surface is a minor arc.

[0009] According to some embodiments of the present invention, a cross section of the first through curved surface and the second through curved surface is a major arc.

[0010] According to some embodiments of the present invention, the first through-cut surface and the second through-cut surface are parallel and close to each other, with a distance between them being less than 1 cm; and the first through-curved surface and the second through-curved surface are far away from each other.

[0011] According to some embodiments of the present invention, the first current collector and the second current collector are respectively located on both sides of the middle position of the open air gap.

[0012] According to some embodiments of the present invention, a distance between the first through section and the second through section is 2-3 mm.

[0013] According to some embodiments of the present invention, the first current collector and the second current collector are made of copper.

[0014] According to some embodiments of the present invention, the open air gap is located directly below the first current collector and the second current collector; and the magnetoresistive element is located in the middle of the open air gap.

[0015] According to some embodiments of the present invention, the magnetoresistive element has a magnetoresistive effect within a preset magnetic field range; and the magnetoresistive element has a Wheatstone bridge structure.

[0016] According to some embodiments of the present invention, a magnetically sensitive direction of the magnetoresistive element is perpendicular to a current direction of the first current collector or the second current collector.

[0017] According to some embodiments of the present invention, the leakage current sensor further includes a housing; The shell comprises an annular cavity for accommodating the magnetic focusing ring, an air gap cavity for accommodating the magnetic resistance element, a first through cavity for accommodating the first current collector, and a second through cavity for accommodating the second current collector; The annular cavity and the air gap cavity form an annular structure; the first through cavity and the second through cavity are both located in the middle area of ​​the annular structure.

[0018] A second aspect of the present invention provides an electronic device, comprising the leakage current sensor described above.

[0019] Therefore, compared with the prior art, the present invention has the following beneficial effects: The leakage current sensor provided by the present invention comprises: a magnetic ring having an open air gap; a first current collector and a second current collector, which respectively penetrate the first inner cavity of the magnetic ring and are respectively coupled in series with the conductor to be measured, and have opposite current directions; a first through-curved surface and a first through-cut surface in the first current collector form a first semicircular tube-shaped structure; a second through-curved surface and a second through-cut surface in the second current collector form a second semicircular tube-shaped structure; the center of the first inner cavity is located at the center of the first structure and the second structure; a magnetoresistive element is located in the open air gap near the center of the first current collector and the second current collector. The present invention realizes leakage current measurement of the conductor to be measured by adjusting the current collector structure and the position of the magnetoresistive element, thereby improving the accuracy of leakage current measurement; it also has the beneficial effects of simple structure and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the structure of a leakage current sensor in one embodiment of the present invention; Figure 2 Schematic diagram of the structure of the first current collector and the second current collector in one embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of a housing in one embodiment of the present invention; Figure 4 A simulation diagram of magnetic field distribution around the first current collector and the second current collector in the comparative example leakage current sensor of the present invention; Figure 5 A simulation diagram of magnetic field distribution around the first current collector and the second current collector in the leakage current sensor according to an embodiment of the present invention; Figure 6 1 is a curve showing the output voltage of the leakage current sensor changing with the load current in a comparative example and an embodiment of the present invention.

[0022] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] In the fields of new energy grid connection, new energy vehicles and safety monitoring, the requirements for single-phase leakage current detection are gradually increasing. Traditional transformers, Hall sensors, fluxgate sensors, etc., when used for leakage current detection, generally have problems such as high cost, poor accuracy, and large size.

[0027] The use of tunnel magnetoresistance (TMR) for leakage current detection has become a new focus. The current in a conventional straight wire will produce common-mode interference, affecting the precision and accuracy of the measurement, and even making it impossible to detect leakage current.

[0028] The purpose of the embodiments of the present invention is to provide a leakage current sensor and an electronic device, which are used to improve the problem that the existing leakage current sensor is affected by common mode interference and cannot accurately measure the leakage current.

[0029] like Figure 1 As shown, the leakage current sensor according to the embodiment of the present invention includes a magnetic focusing ring 10 , a first current collector 20 , a second current collector 30 and a magnetoresistive element 40 .

[0030] The magnetic focusing ring 10 of the embodiment of the present invention is an open annular structure, that is, it has an open air gap 50 for gathering the magnetic flux of the first inner cavity surrounded by the magnetic focusing ring 10 into the open air gap.

[0031] It should be understood that the magnetic concentrator 10 should have high magnetic permeability and low coercive force.

[0032] The first current collector 20 and the second current collector 30 have the same structure, respectively pass through the first inner cavity, have current directions opposite to each other, and are respectively coupled in series with the wire to be tested (not shown).

[0033] Assuming that the load current of the wire to be tested is 1A, when there is no leakage current, the absolute value of the load current of the first current collector 20 and the second current collector 30 should also be 1A.

[0034] To achieve better conductivity, the first current collector 20 and the second current collector 30 of the embodiment of the present invention are made of copper. The first current collector and the second current collector may also be made of other conductive materials, which are not specifically limited here.

[0035] like Figure 2 As shown, the first current collector 20 of the embodiment of the present invention includes a first through curved surface 21 and a first through cut surface 22, and the first through curved surface 21 and the first through cut surface 22 form a first semicircular tube-shaped structure. The cross section of the first through curved surface is a semicircle.

[0036] It should be noted that the cross section of the first through curved surface 21 can be a semicircle, a minor arc or a major arc. It is not limited to a semicircle. When the cross section of the first through curved surface 21 is a minor arc, the cross section is an arc smaller than a semicircle, and the corresponding center angle is less than 180 degrees; when the cross section of the first through curved surface 21 is a major arc, the cross section is an arc larger than a semicircle, and the corresponding center angle is greater than 180 degrees and less than 360 degrees. The thickness of the first through curved surface is not limited here.

[0037] like Figure 2 As shown, the second current collector 30 of the embodiment of the present invention includes a second through curved surface 31 and a second through cut surface 32 , and the second through curved surface 31 and the second through cut surface 32 form a second semicircular tube-shaped structure.

[0038] Here, the second through curved surface 31 has the same structure as the first through curved surface 21 , and the cross section can be a semicircle, a minor arc, or a major arc. The second through curved surface 31 and the first through curved surface 21 also have the same thickness.

[0039] like Figure 1 As shown, the center of the first inner cavity in the magnetic focusing ring 10 of the embodiment of the present invention is located at the center of the first structure and the second structure. That is, the first current collector 20 and the second current collector 30 are respectively located on both sides of the center of the first inner cavity.

[0040] Furthermore, in the embodiment of the present invention, the first current collector 20 and the second current collector 30 are mirror structures, that is, the first through-cut surface 22 and the second through-cut surface 32 are parallel and close to each other, and the first through-curved surface 21 and the second through-curved surface 31 are far away from each other. The center of the first inner cavity is located on the center plane of the first through-cut surface 22 and the second through-cut surface 32.

[0041] In the embodiment of the present invention, the distance between the first through-section surface 22 and the second through-section surface 32 is 2.5 mm.

[0042] It should be noted that the distance between the first through section 22 and the second through section 32 may be less than 1 cm, preferably 2-3 mm.

[0043] The magnetoresistive element 40 of the embodiment of the present invention is located in the open air gap of the magnetic focusing ring close to the center of the first current collector 20 and the second current collector 30, and is used to sense the current condition of the conductor to be tested.

[0044] It should be understood that the position of the open air gap 50 is determined by the positions of the first current collector 20 and the second current collector 30. The center plane between the first current collector 20 and the second current collector 30 passes through the open air gap 50.

[0045] The center plane between the first current collector 20 and the second current collector 30 of the embodiment of the present invention passes through the middle position of the open air gap 50. The magnetoresistive element is located in the middle position of the open air gap 50. At the same time, the open air gap is located directly below the first current collector 20 and the second current collector 30.

[0046] It should be noted that the open air gap 50 is not limited to the position directly below the first current collector 20 and the second current collector 30, but can also be directly above them; the center plane between the first current collector 20 and the second current collector 30 passes through any position in the open air gap 50, such as the left side position or the right side position, and is not limited to the center position of the open air gap 50.

[0047] The magnetoresistive element 40 of the embodiment of the present invention has a magnetoresistive effect within a preset magnetic field range and has a Wheatstone bridge structure.

[0048] In order to better sense the magnetic flux at the position of the open air gap 50 , the magnetically sensitive direction of the magnetoresistive element 50 in the embodiment of the present invention is perpendicular to the current direction of the first current collector 20 and the second current collector 30 .

[0049] It should be noted that the magnetic sensitivity direction of the magnetoresistive element 40 is determined by the placement direction of the magnetoresistive element in the open air gap, which is not specifically limited here.

[0050] In the embodiment of the present invention, the positions of the first current collector 20, the second current collector 30 and the magnetic focusing ring are fixed. The first current collector 20 and the second current collector 30 both penetrate the magnetic focusing ring, and the distance between the first current collector and the center of the magnetic focusing ring cannot be changed at will.

[0051] It should be noted that when the positions of the first current collector, the second current collector and the magnetic focusing ring change, the leakage magnetic field induced by the magnetic element may change.

[0052] Furthermore, the embodiment of the present invention further includes a housing. Figure 3 As shown, the housing at least includes an annular cavity 61, an air gap cavity 62, a first through cavity 63 and a second through cavity 64. The annular cavity 61 is used to accommodate the magnetic focusing ring 10; the air gap cavity 62 is used to accommodate the magnetic resistance element 40, and the annular cavity 61 and the air gap cavity 62 form an annular structure; the first through cavity 63 is used to accommodate the first current collector 20, and the second through cavity 64 is used to accommodate the second current collector 30; the first through cavity 63 and the second through cavity 64 are both located in the central area of ​​the annular structure and are symmetrically arranged on both sides of the center of the annular structure.

[0053] The central plane of the annular structure in the embodiment of the present invention passes through the air gap cavity, and the first through cavity 63 and the second through cavity 64 are respectively located on both sides of the central plane.

[0054] The current measurement effect of the leakage current sensor according to the embodiment of the present invention is verified as follows.

[0055] The comparative leakage current sensor is different from the leakage current sensor of the embodiment of the present invention only in the shapes of the first current collector and the second current collector. In the comparative leakage current sensor, the shapes of the first current collector and the second current collector are replaced by round wires.

[0056] When the load current of the first current collector is 50A and the load current of the second current collector is -50A, the simulated magnetic field distribution around the first current collector and the second current collector in the comparative leakage current sensor is as follows: Figure 4 shown.

[0057] in accordance with Figure 4 , the magnetic field is distributed very unevenly around the magnetic focusing ring. Affected by common mode interference, the high-intensity magnetic field is concentrated at the location of the magnetic focusing ring. The magnetic flux density at the location of the magnetic focusing ring is 2~14mT. Figure 4 , magnetic lines of force pass through the open air gap through the magnetic concentrator ring, and the magnetic flux density is greater than 0. During the test, the current direction of the first current collector and the second current collector are opposite, and the current value is the same, and there is no leakage current. However, the open air gap position simulated by the proportional leakage current sensor has a certain magnetic flux density. Therefore, the proportional current sensor cannot truly feedback the leakage current situation.

[0058] When the load current of the first current collector is 50A and the load current of the second current collector is -50A, the simulated magnetic field distribution around the first current collector and the second current collector in the leakage current sensor according to the embodiment of the present invention is as follows: Figure 5 shown.

[0059] in accordance with Figure 5 The high-intensity magnetic field is mainly concentrated between the first current collector and the second current collector, and the magnetic field at other locations is relatively weak. The magnetic field distribution at the magnetic focusing ring is relatively uniform, and its magnetic flux density is less than 4mT.

[0060] in accordance with Figure 5 , the magnetic lines of force bypass the open air gap position, and the magnetic flux density at the open air gap position is close to zero. Figure 5 , the magnetic flux density at the position directly above or directly below the first current collector and the second current collector is small; the farther the lateral distance from the center of the first inner cavity, the greater the magnetic flux density, and the opening position of the open air gap is preferably directly above or directly below the first current collector and the second current collector. Therefore, the leakage current sensor of the present invention can feedback the true situation of the current leakage current and can be used for leakage current measurement.

[0061] Furthermore, the comparative leakage current sensor and the leakage current sensor of the present invention are used for leakage current detection of different load currents, and the change of their output voltage is observed. When the load current of the wire to be tested is 0-30A, the output voltage of the comparative leakage current sensor and the leakage current sensor of the present invention varies with the load current. Figure 6 As shown. Figure 6 , as the load current increases, the output voltages of the leakage current sensor of the embodiment of the present invention and the comparative leakage current sensor both increase linearly with the increase of the load current, and the output voltage of the leakage current sensor of the embodiment of the present invention decreases significantly with the change trend of the load current. When the load current is 20A, the output voltage of the comparative leakage current sensor is higher than 1100mV, while the output voltage of the leakage current sensor of the embodiment of the present invention is only 200mV, which is less than 1 / 5 of the output voltage of the comparative leakage current sensor. Therefore, the leakage current sensor of the embodiment of the present invention is suitable for the detection of leakage current and has higher measurement accuracy.

[0062] Therefore, the embodiment of the present invention achieves leakage current measurement of the conductor to be measured by adjusting the structure of the current collector and the position of the magnetoresistive element, thereby improving the accuracy of leakage current measurement; it also has the beneficial effects of simple structure and easy implementation.

[0063] An embodiment of the present invention further provides an electronic device, which includes the aforementioned leakage current sensor.

[0064] The electronic device can monitor the leakage current of other circuits in the electronic device through the leakage current sensor, and ensure the normal use of the electronic device according to the leakage current feedback from the leakage current sensor.

[0065] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A leakage current sensor, characterized in that: include: A magnetic concentrating ring having an open air gap, used for concentrating the magnetic flux of the first inner cavity surrounded by the magnetic concentrating ring to the open air gap; The first current collector and the second current collector of the same structure respectively penetrate the first inner cavity, have current directions opposite to each other, and are respectively coupled in series with the wire loop to be tested; the first through-curved surface and the first through-cut surface of the first current collector form a first semicircular tube-shaped structure; the second through-curved surface and the second through-cut surface of the second current collector form a second semicircular tube-shaped structure; the center of the first inner cavity is located at the center position of the first structure and the second structure; The magnetoresistive element is located in the open air gap near the center of the first current collector and the second current collector, and is used to sense the current condition of the conductor to be measured.

2. The leakage current sensor according to claim 1, characterized in that: The cross-sections of the first through curved surface and the second through curved surface are a semicircle, a minor arc or a major arc.

3. The leakage current sensor according to claim 1 or 2, characterized in that: The first through section and the second through section are parallel and close to each other, and the distance between them is less than 1 cm; The first through curved surface and the second through curved surface are far away from each other.

4. The leakage current sensor according to claim 3, characterized in that: The first current collector and the second current collector are respectively located on two sides of the middle position of the open air gap.

5. The leakage current sensor according to claim 3, characterized in that: The distance between the first through section and the second through section is 2-3 mm.

6. The leakage current sensor according to claim 2, characterized in that: The first current collector and the second current collector are made of copper.

7. The leakage current sensor according to claim 2, characterized in that: The open air gap is located directly below the first current collector and the second current collector; The magnetoresistive element is located in the middle of the open air gap.

8. The leakage current sensor according to any one of claims 1 to 7, characterized in that: The magnetoresistive element has a magnetoresistive effect within a preset magnetic field range; the magnetoresistive element has a Wheatstone bridge structure; The magnetically sensitive direction of the magnetoresistive element is perpendicular to the current direction of the first current collector or the second current collector.

9. The leakage current sensor according to claim 8, characterized in that: The leakage current sensor also includes a housing; The shell comprises an annular cavity for accommodating the magnetic focusing ring, an air gap cavity for accommodating the magnetic resistance element, a first through cavity for accommodating the first current collector, and a second through cavity for accommodating the second current collector; The annular cavity and the air gap cavity form an annular structure; the first through cavity and the second through cavity are both located in the middle area of ​​the annular structure.

10. An electronic device, characterized in that: The invention comprises the leakage current sensor according to any one of claims 1 to 9.

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