Fluxgate current sensor chip and manufacturing method and application method

Abstract

The present invention relates to the field of sensor technology, and provides a fluxgate current sensor chip, a manufacturing method, and an application method. The fluxgate current sensor chip includes: a first sensitive unit, a second sensitive unit, and a conductor channel between the first sensitive unit and the second sensitive unit. Each sensitive unit includes a magnetic core and a coil. The coil includes an excitation coil and an induction coil. The excitation coil and the induction coil are wound on the magnetic core, and the axis of the magnetic core wound by the induction coil serves as the sensitive axis of the sensitive unit. The first sensitive unit and the second sensitive unit detect the current to be measured by sensing the magnetic field near the upper surface and the magnetic field near the lower surface of the conductor channel. The present invention adopts two sensitive units and the conductor channel therebetween to form a differential detection structure, and does not need to use a magnetic focusing ring structure, so as to realize the chip of the current sensor, with high detection accuracy and strong anti-interference ability. It can realize open-loop and closed-loop current detection, and can meet the current detection requirements of various application scenarios.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a fluxgate current sensor chip and a manufacturing method and an application method thereof. Background Art

[0002] In the power system, current detection is an important means to monitor the status of power equipment to ensure the safe operation of power equipment. In order to meet the requirements of application scenarios, installation methods, and maintenance difficulty, current sensors are developing in the direction of small size, low power consumption, low cost, easy installation and maintenance, and intelligence. At present, most current sensors are through-type applications, using a closed core winding method to form an electromagnetic induction structure for current detection, or using a magnetic ring structure to converge the magnetic field generated by the current to be measured to the open air gap of the magnetic ring, which is detected by a magnetic sensitive element. This type of current sensor has a simple structure and is easy to install, but it is large in size, heavy in weight, and high in cost, and the current detection performance is affected by core saturation, magnetic leakage, hysteresis, etc.

[0003] In order to reduce the volume, cost and power consumption of the current detection system, current sensors without a magnetic ring structure have been developed. Existing current sensors without a magnetic ring structure can be divided into three categories: the first category uses a PCB board to fix the magnetic sensitive element, and then assembles it with the wire to be tested. The manufacturing process of this type of current sensor is complex; the second category uses a ring array composed of magnetic sensitive elements to replace the magnetic ring structure, and then combines a complex algorithm to achieve through-type current detection, but the number, position, installation accuracy of the magnetic sensitive element array and the conductor eccentricity caused by mechanical disturbances will affect the detection accuracy of this type of current sensor; the third category uses busbar perforation or slotting to fix the magnetic sensitive element to achieve current differential detection, but this type of current sensor has high requirements for the position accuracy of the magnetic sensitive element, and the side slots will cause the busbar to reduce the mechanical strength and heat up seriously. In general, the existing current sensors have problems such as large size, high cost, and complex production process, making it difficult to realize the chipization of current sensors. Summary of the invention

[0004] In order to solve the problems of large size, high cost and complex production process of existing current sensors, the present invention provides a fluxgate current sensor chip and a manufacturing method and an application method.

[0005] The fluxgate current sensor chip provided by the present invention comprises: a first sensitive unit, a second sensitive unit and at least one conductor channel between the first sensitive unit and the second sensitive unit, wherein the first sensitive unit is located on the upper surface of the conductor channel, and the second sensitive unit is located on the lower surface of the conductor channel;

[0006] The first sensitive unit and the second sensitive unit both include a magnetic core and a coil, the coil includes an excitation coil and an induction coil, the excitation coil and the induction coil are wound on the magnetic core, and the axis of the magnetic core around which the induction coil is wound serves as the sensitive axis of the sensitive unit;

[0007] When the conductor channel is connected to the current to be measured, the current to be measured flowing through the conductor channel generates magnetic fields in opposite directions near the upper surface and the lower surface of the conductor channel, the magnetic field near the upper surface of the conductor channel is parallel to the sensitive axis of the first sensitive unit, and the magnetic field near the lower surface of the conductor channel is parallel to the sensitive axis of the second sensitive unit;

[0008] The first sensitive unit and the second sensitive unit form a differential detection structure. The first sensitive unit and the second sensitive unit detect the current to be measured by sensing the magnetic field near the upper surface and the magnetic field near the lower surface of the conductor channel.

[0009] In the embodiment of the present invention, the distance between the first sensitive unit and the upper surface of the conductor channel and the distance between the second sensitive unit and the lower surface of the conductor channel are equal.

[0010] The magnetic field near the upper surface of the conductor channel sensed by the first sensitive unit and the magnetic field near the lower surface of the conductor channel sensed by the second sensitive unit are equal in magnitude and opposite in direction.

[0011] In the embodiment of the present invention, the excitation coil and the induction coil are the same group of spiral coils, and the axis of the magnetic core wound around the spiral coils serves as the sensitive axis of the sensitive unit.

[0012] In the embodiment of the present invention, the excitation coil includes at least one group of spiral coils, and the induction coil includes at least one group of spiral coils. The spiral coils serving as induction coils and the spiral coils serving as excitation coils are both wound on the sensitive axis of the magnetic core.

[0013] In an embodiment of the present invention, the excitation coil includes at least one group of spiral coils, and the induction coil includes at least one group of spiral coils. The spiral coils serving as induction coils are wound on the sensitive axis of the magnetic core, and the spiral coils serving as excitation coils are wound on the non-sensitive axis of the magnetic core.

[0014] In an embodiment of the present invention, the excitation coil includes a plurality of groups of spiral coils, and the plurality of groups of spiral coils serving as the excitation coils are connected in series.

[0015] In the embodiment of the present invention, the induction coil includes a plurality of groups of spiral coils, and the plurality of groups of spiral coils serving as the induction coils are connected in parallel.

[0016] In the embodiment of the present invention, the magnetic core of each sensitive unit is in any one of a rod shape, a rectangle shape, a ring shape, a racetrack shape, and a hexagon shape, and the structure of the magnetic core is an open structure or a closed structure.

[0017] In the embodiment of the present invention, the material of the conductor channel is metal or metal alloy.

[0018] In the embodiment of the present invention, the cross-sectional shape of the conductor channel is rectangular, elliptical or polygonal.

[0019] In the embodiment of the present invention, the conductor channel is located in the gap between the sensitive axes of the two sensitive units.

[0020] In an embodiment of the present invention, each sensitive unit includes at least one pair of input ports;

[0021] The input port is connected to the excitation coil and is used to apply an excitation signal to the excitation coil;

[0022] The input port also serves as an output port for outputting the sensing signal of the sensitive unit.

[0023] In an embodiment of the present invention, each sensitive unit includes at least one pair of input ports and at least one pair of output ports;

[0024] The input port is connected to the excitation coil and is used to apply an excitation signal to the excitation coil;

[0025] The output port is connected to the induction coil and is used to output the induction signal of the induction coil.

[0026] In the embodiment of the present invention, the number of the conductor channels is two.

[0027] The two conductor channels are arranged transversely to the sensitive axis of the magnetic core.

[0028] In the embodiment of the present invention, a conductor interface is respectively provided at both ends of each conductor channel.

[0029] The present invention also provides a method for manufacturing the fluxgate current sensor chip, wherein the first method is:

[0030] preparing two groups of wafers, each group of wafers including two wafers;

[0031] For two wafers in each group of wafers, a coil groove is etched on one surface of a first wafer, a magnetic core groove is etched on a first surface of a second wafer, and a coil groove is etched on a second surface of the second wafer;

[0032] Forming a half-cavity structure corresponding to the conductor channel on one of the wafers in one group of wafers, and forming a half-cavity structure corresponding to the conductor channel on one of the wafers in another group of wafers;

[0033] For each set of wafers, the prefabricated cores are placed in the core slots of the second wafer;

[0034] For each group of wafers, a first wafer in the group of wafers is combined with a second wafer to form a closed coil slot wound on a magnetic core;

[0035] Combining the two groups of wafers so that the half-cavity structures corresponding to the conductor channels in the two groups of wafers form an overall cavity structure corresponding to the conductor channel;

[0036] Filling coil materials in the closed coil slots in each group of wafers to form a closed coil wound around a magnetic core, thereby obtaining two groups of wafers as sensitive units;

[0037] Conductive material is filled in the overall cavity structure of the corresponding conductor channel between the two groups of wafers to form a conductor channel between the two groups of wafers. The two groups of wafers as sensitive units and the conductor channel between the two groups of wafers constitute a group of fluxgate current sensor chips.

[0038] The first method can also be:

[0039] preparing two groups of wafers, each group of wafers including two wafers;

[0040] For two wafers in each group of wafers, a coil groove is etched on one surface of a first wafer, a magnetic core groove is etched on a first surface of a second wafer, and a coil groove is etched on a second surface of the second wafer;

[0041] forming an overall cavity structure corresponding to the conductor channel on one of the two groups of wafers;

[0042] For each set of wafers, the prefabricated cores are placed in the core slots of the second wafer;

[0043] For each group of wafers, a first wafer in the group of wafers is combined with a second wafer to form a closed coil slot wound on a magnetic core;

[0044] Combining the two groups of wafers so that the overall cavity structure of the corresponding conductor channel on one of the wafers is located between the two groups of wafers;

[0045] Filling coil materials in the closed coil slots in each group of wafers to form a closed coil wound around a magnetic core, thereby obtaining two groups of wafers as sensitive units;

[0046] Conductive material is filled in the overall cavity structure of the corresponding conductor channel between the two groups of wafers to form a conductor channel between the two groups of wafers. The two groups of wafers as sensitive units and the conductor channel between the two groups of wafers constitute a group of fluxgate current sensor chips.

[0047] The present invention also provides a method for manufacturing the fluxgate current sensor chip, wherein the second method is:

[0048] Prepare three groups of wafers, each group of wafers includes two wafers;

[0049] Selecting a first group of wafers and a second group of wafers from the three groups of wafers, etching a coil groove on one surface of the first wafer, etching a magnetic core groove on a first surface of the second wafer, and etching a coil groove on a second surface of the second wafer for two wafers from the first group of wafers and two wafers from the second group of wafers;

[0050] For the first group of wafers and the second group of wafers, placing the prefabricated magnetic core in the magnetic core slot of the second wafer of each group of wafers;

[0051] The first wafer in each set of wafers is combined with the second wafer to form a closed coil slot wound on the magnetic core;

[0052] Filling coil materials in closed coil slots in the first group of wafers and the second group of wafers to form closed coils wound around a magnetic core, thereby obtaining two groups of wafers containing sensitive units;

[0053] forming an overall cavity structure corresponding to the conductor channel on each wafer of the third group of wafers;

[0054] Filling the overall cavity structure of the corresponding conductor channels on the third group of wafers with a conductor material to form a conductor channel;

[0055] The three groups of wafers are combined so that the third group of wafers is located between the first group of wafers and the second group of wafers. The first group of wafers and the second group of wafers as sensitive units and the third group of wafers as conductor channels constitute a group of fluxgate current sensor chips.

[0056] The second method can also be:

[0057] Prepare three groups of wafers, each group of wafers includes two wafers;

[0058] Selecting a first group of wafers and a second group of wafers from the three groups of wafers, etching a coil groove on one surface of the first wafer, etching a magnetic core groove on a first surface of the second wafer, and etching a coil groove on a second surface of the second wafer for two wafers from the first group of wafers and two wafers from the second group of wafers;

[0059] For the first group of wafers and the second group of wafers, placing the prefabricated magnetic core in the magnetic core slot of the second wafer of each group of wafers;

[0060] The first wafer in each set of wafers is combined with the second wafer to form a closed coil slot wound on the magnetic core;

[0061] Filling coil materials in closed coil slots in the first group of wafers and the second group of wafers to form closed coils wound around a magnetic core, thereby obtaining two groups of wafers containing sensitive units;

[0062] forming a half-cavity structure corresponding to the conductor channel on one of the wafers in the third group of wafers, and forming a half-cavity structure corresponding to the conductor channel on another wafer in the third group of wafers;

[0063] Combining the two wafers of the third group so that the half-cavity structures corresponding to the conductor channels in the two wafers form an overall cavity structure corresponding to the conductor channels;

[0064] Filling the overall cavity structure of the corresponding conductor channels on the third group of wafers with a conductor material to form a conductor channel;

[0065] The three groups of wafers are combined so that the third group of wafers is located between the first group of wafers and the second group of wafers. The first group of wafers and the second group of wafers as sensitive units and the third group of wafers as conductor channels constitute a group of fluxgate current sensor chips.

[0066] The present invention also provides an application method of the above-mentioned fluxgate current sensor chip, including: selecting a conductor interface corresponding to a conductor channel of the fluxgate current sensor chip to connect to a single busbar, so as to realize open-loop detection of leakage current or busbar current.

[0067] The method further includes: selecting conductor interfaces corresponding to two conductor channels of the fluxgate current sensor chip to be connected to the L line and the N line respectively, so as to realize open-loop detection of the residual current.

[0068] The method further includes: selecting a conductor interface corresponding to one of the conductor channels of the fluxgate current sensor chip to connect to the current to be measured, and connecting a conductor interface corresponding to another conductor channel to a feedback circuit to achieve closed-loop detection of the current to be measured.

[0069] The method also includes: for the three-phase current to be measured, four fluxgate current sensor chips are used, and the conductor interfaces corresponding to the conductor channels of each fluxgate current sensor chip are respectively connected to the A, B, C and N lines to realize open-loop detection of the three-phase current to be measured.

[0070] The method also includes: for the three-phase current to be measured, four fluxgate current sensor chips are used, and the conductor interface corresponding to one conductor channel of each fluxgate current sensor chip is connected to the A, B, C and N lines respectively, and the conductor interface corresponding to the other conductor channel of each fluxgate current sensor chip is connected to the feedback circuit to realize closed-loop detection of the three-phase current to be measured.

[0071] The fluxgate current sensor chip of the present invention adopts two sensitive units and a conductor channel between the two sensitive units to form a differential detection structure, and does not need to use a magnetic focusing ring structure, thereby realizing the current sensor chip. The chip adopts the fluxgate principle, has high detection accuracy, strong anti-interference ability, and has a measurement range from milliamperes to tens of amperes, which can meet various needs such as insulation monitoring, ground fault monitoring, residual current detection, AC and DC metering detection, etc. The chip does not require a magnetic focusing ring structure, can be applied to open-loop and closed-loop current detection, and can meet the needs of high-precision, high-bandwidth AC and DC current detection from milliamperes to amperes. The chip structure is entirely manufactured based on MEMS technology, with simple technology, high integration, easy large-scale production, small chip size, low cost, and good consistency.

[0072] Other features and advantages of the technical solution of the present invention will be described in detail in the specific implementation section below. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0074] Figure 1 is a three-dimensional diagram of a fluxgate current sensor chip provided in the first embodiment of the present invention;

[0075] Figure 2 is a front view of a fluxgate current sensor chip provided in the first embodiment of the present invention;

[0076] Figure 3 is a side view of the fluxgate current sensor chip provided in the first embodiment of the present invention;

[0077] Figure 4 is a three-dimensional diagram of a fluxgate current sensor chip provided in the second embodiment of the present invention;

[0078] Figure 5 is a front view of a fluxgate current sensor chip provided in the second embodiment of the present invention;

[0079] Figure 6 is a side view of a fluxgate current sensor chip provided in the second embodiment of the present invention;

[0080] Figure 7 is a flow chart of a method for manufacturing a fluxgate current sensor chip provided in Embodiment 1 of the present invention;

[0081] Figure 8 is a flow chart of a method for manufacturing a fluxgate current sensor chip provided in Embodiment 2 of the present invention;

[0082] Fig. 9This is an application diagram of the fluxgate current sensor chip provided by the embodiment of the present invention. Figure 1 ;

[0083] Fig.10 This is an application diagram of the fluxgate current sensor chip provided by the embodiment of the present invention. Figure 2 .

[0084] Description of Reference Numerals

[0085] 1-magnetic core, 2-excitation coil, 3-induction coil, 4-input port, 5-output port,

[0086] 6-Conductor channel. DETAILED DESCRIPTION

[0087] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0088] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. The terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0089] In the present invention, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0090] In order to solve the problems of large volume, high cost and complex production process of existing current sensors, the present invention provides a fluxgate current sensor chip, which includes a first sensitive unit, a second sensitive unit and at least one conductor channel between the first sensitive unit and the second sensitive unit, wherein the first sensitive unit is located on the upper surface of the conductor channel and the second sensitive unit is located on the lower surface of the conductor channel. Each sensitive unit includes a magnetic core and a coil, wherein the coil is wound on the magnetic core, and the coil includes at least one group of excitation coils (the excitation coil is also used as an induction coil), or includes at least one group of excitation coils and at least one group of induction coils. The axis of the magnetic core wound by the induction coil serves as the sensitive axis of the sensitive unit. When the conductor channel is connected to the current to be measured, the current to be measured flowing through the conductor channel generates magnetic fields in opposite directions near the upper surface and the lower surface of the conductor channel, wherein the magnetic field near the upper surface of the conductor channel is parallel to the sensitive axis of the first sensitive unit, and the magnetic field near the lower surface of the conductor channel is parallel to the sensitive axis of the second sensitive unit. The first sensitive unit and the second sensitive unit constitute a differential detection structure, and the detection of the current to be measured is achieved by sensing the magnetic field near the upper surface and the magnetic field near the lower surface of the conductor channel. The present invention adopts the fluxgate principle and is designed as a differential detection structure of two fluxgate sensitive units and a conductor channel integrated between the sensitive units. No magnetic focusing ring structure is required to realize the chipization of the current sensor. The chip adopts the fluxgate principle, has high detection accuracy, strong anti-interference ability, and has a measurement range from milliamperes to tens of amperes. It can meet various needs such as insulation monitoring, ground fault monitoring, residual current detection, AC and DC metering detection, and can realize open-loop and closed-loop current detection. The chip structure of the present invention is all based on MEMS (Micro-Electro-Mechanical System) process processing and manufacturing, with simple process, high integration, easy large-scale production, small chip size, low cost, and good consistency.

[0091] The technical solution of the present invention is described in detail below through specific embodiments.

[0092] Embodiment 1

[0093] like Figure 1 , Figure 2 and Figure 3As shown, this embodiment provides a single-line integrated fluxgate current sensor chip, including a first sensitive unit and a second sensitive unit (two sensitive units) and a conductor channel 6 between the first sensitive unit and the second sensitive unit. The first sensitive unit and the second sensitive unit have the same structure, and both the first sensitive unit and the second sensitive unit include a magnetic core 1, two groups of excitation coils 2 and a group of induction coils 3, and the excitation coils 2 and the induction coils 3 are wound on the magnetic core 1. The first sensitive unit is located on the upper surface of the conductor channel 6, and the second sensitive unit is located on the lower surface of the conductor channel 6. The two sensitive units and the conductor channel 6 integrated between the two sensitive units form a sandwich structure. When the conductor channel 6 is connected to the current to be measured, the current to be measured flowing through the conductor channel generates magnetic fields in opposite directions near the upper surface and the lower surface of the conductor channel. The magnetic field near the upper surface of the conductor channel passes through the induction coil of the first sensitive unit, and the magnetic field near the lower surface of the conductor channel passes through the induction coil of the second sensitive unit. The first sensitive unit and the second sensitive unit constitute a differential detection structure, and the first sensitive unit and the second sensitive unit detect the current to be measured by sensing the magnetic field near the upper surface and the magnetic field near the lower surface of the conductor channel.

[0094] In this embodiment, the magnetic core of each sensitive unit is a closed structure in the shape of a racetrack, and the two long axes of the racetrack-shaped magnetic core serve as the sensitive axes of the magnetic core, that is, one magnetic core has two symmetrical sensitive axes. The direction of the magnetic field generated by the current to be measured flowing through the conductor channel is parallel to the direction of the sensitive axis of the magnetic core. In other embodiments, the magnetic core can be an open structure. The shape of the magnetic core can be rod-shaped, rectangular, ring-shaped or hexagonal. The sensitive axis of the magnetic core can be one or more.

[0095] In this embodiment, the cross-sectional thickness of the conductor channel is relatively thin, which is suitable for the case where the current flowing through the conductor channel is a small current. The cross-sectional shape of the conductor channel is rectangular. When the rectangular conductor channel is connected to the current to be measured, the magnitude of the magnetic field near the upper surface of the conductor channel is equal to the magnitude of the magnetic field near the lower surface of the conductor channel, and the direction is opposite. In other embodiments, the cross-sectional shape of the conductor channel can also be designed to be an ellipse, a polygon, or the like.

[0096] In this embodiment, the distance between the first sensitive unit and the upper surface of the conductor channel and the distance between the second sensitive unit and the lower surface of the conductor channel are equal. The magnetic field near the upper surface of the conductor channel sensed by the first sensitive unit and the magnetic field near the lower surface of the conductor channel sensed by the second sensitive unit are equal in magnitude and opposite in direction.

[0097] In this embodiment, each sensitive unit has multiple groups of excitation coils, that is, the excitation coils include multiple groups of spiral coils, and the multiple groups of spiral coils are connected in series. The multiple groups of excitation coils are respectively wound on both ends of the two sensitive axes of the magnetic core, and the multiple groups of excitation coils are symmetrically distributed. In other embodiments, the excitation coils can be wound on the non-sensitive axes of the magnetic core (such as the two short axes of the above-mentioned racetrack-shaped magnetic core).

[0098] In this embodiment, each sensitive unit has multiple induction coils, that is, the induction coils include multiple spiral coils, and the multiple spiral coils are connected in parallel. The multiple induction coils are wound around the middle of the two sensitive axes of the magnetic core. The conductor channel is located in the gap between the sensitive axes of the two sensitive units.

[0099] In other embodiments, the excitation coil and the induction coil may be formed by the same set of spiral coils, and one axis or multiple axes of the magnetic core wound around the spiral coils serve as the sensitive axis of the sensitive unit.

[0100] In other embodiments, the excitation coil includes one or more groups of spiral coils, and the induction coil includes one or more groups of spiral coils, and the spiral coils as the induction coils and the spiral coils as the excitation coils are both wound on the sensitive axis of the magnetic core; or, the spiral coils as the induction coils are wound on the sensitive axis of the magnetic core, and the spiral coils as the excitation coils are wound on the non-sensitive axis of the magnetic core. If the excitation coil includes multiple groups of spiral coils, the multiple groups of spiral coils as the excitation coils are connected in series. If the induction coil includes multiple groups of spiral coils, the multiple groups of spiral coils as the induction coils are connected in parallel.

[0101] In this embodiment, each sensitive unit includes a pair of input ports 4 and a pair of output ports 5. The input port 4 is connected to the excitation coil 2 and is used to apply an excitation signal to the excitation coil. The output port 5 is connected to the induction coil 3 and is used to output the induction signal of the induction coil. In other embodiments, the number of input ports and output ports of each sensitive unit can be set according to actual needs. Each sensitive unit can be provided with only one pair of input ports, or two or more pairs of input ports and two or more pairs of output ports. For example, if the coil of the sensitive unit only includes the excitation coil, and the excitation coil is also used as the induction coil, only the input port is provided, and the input port is connected to the excitation coil. At this time, the input port also serves as the output port, applies the excitation signal to the excitation coil and outputs the induction signal. If the coil of the sensitive unit includes the excitation coil and the induction coil, the input port and the output port are provided, the input port is connected to the excitation coil, applies the excitation signal to the excitation coil, and the output port is connected to the induction coil, and outputs the induction signal of the induction coil.

[0102] In this embodiment, a conductor interface (not shown in the drawings) is respectively provided at both ends of each conductor channel.

[0103] In this embodiment, the material of the magnetic core of the sensitive unit can be soft magnetic materials such as Permalloy material, amorphous material or nanocrystalline alloy material. The material of the excitation coil and the induction coil can be a single metal material or an alloy material. The material of the conductor channel is a metal or metal alloy with good electrical conductivity, such as copper, aluminum, aluminum alloy, silver alloy, etc., and liquid copper can also be selected.

[0104] Embodiment 2

[0105] like Figure 4 , Figure 5 and Figure 6 As shown, this embodiment provides a two-wire integrated fluxgate current sensor chip, including a first sensitive unit and a second sensitive unit (two sensitive units) and two conductor channels 6 between the first sensitive unit and the second sensitive unit. The first sensitive unit and the second sensitive unit have the same structure, and both the first sensitive unit and the second sensitive unit include a magnetic core 1, two groups of excitation coils 2 and a group of induction coils 3, and the excitation coils 2 and the induction coils 3 are wound on the magnetic core 1. The first sensitive unit is located on the upper surface of the conductor channel 6, and the second sensitive unit is located on the lower surface of the conductor channel 6. The two sensitive units and the conductor channel 6 integrated between the two sensitive units form a sandwich structure. When the conductor channel 6 is connected to the current to be measured, the current to be measured flowing through the conductor channel generates magnetic fields in opposite directions near the upper surface and the lower surface of the conductor channel. The magnetic field near the upper surface of the conductor channel passes through the induction coil of the first sensitive unit, and the magnetic field near the lower surface of the conductor channel passes through the induction coil of the second sensitive unit. The first sensitive unit and the second sensitive unit constitute a differential detection structure, and the first sensitive unit and the second sensitive unit detect the current to be measured by sensing the magnetic field near the upper surface and the magnetic field near the lower surface of the conductor channel.

[0106] In this embodiment, the magnetic core of each sensitive unit is a closed structure in the shape of a racetrack, and the two long axes of the racetrack-shaped magnetic core serve as the sensitive axes of the magnetic core, that is, one magnetic core has two symmetrical sensitive axes. The direction of the magnetic field generated by the current to be measured flowing through the conductor channel is parallel to the direction of the sensitive axis of the magnetic core. In other embodiments, the magnetic core can be an open structure. The shape of the magnetic core can be rod-shaped, rectangular, ring-shaped or hexagonal. The sensitive axis of the magnetic core can be one or more.

[0107] In this embodiment, the two conductor channels are arranged transversely to the sensitive axis of the magnetic core. The cross-sectional thickness of the conductor channel is relatively thick, which is suitable for the case where the current flowing through the conductor channel is a large current. The two conductor channels are of the same size, and the cross-sectional shapes of the two conductor channels are both rectangular. When the rectangular conductor channel is connected to the current to be measured, the magnitude of the magnetic field near the upper surface of the conductor channel is equal to the magnitude of the magnetic field near the lower surface of the conductor channel, and the direction is opposite. In other embodiments, the cross-sectional shapes of the two conductor channels can also be designed to be elliptical, polygonal, and the like.

[0108] In this embodiment, the distance between the first sensitive unit and the upper surface of the conductor channel and the distance between the second sensitive unit and the lower surface of the conductor channel are equal. The magnetic field near the upper surface of the conductor channel sensed by the first sensitive unit and the magnetic field near the lower surface of the conductor channel sensed by the second sensitive unit are equal in magnitude and opposite in direction.

[0109] In this embodiment, each sensitive unit has multiple groups of excitation coils, that is, the excitation coils include multiple groups of spiral coils, and the multiple groups of spiral coils are connected in series. The multiple groups of excitation coils are respectively wound on both ends of the two sensitive axes of the magnetic core, and the multiple groups of excitation coils are symmetrically distributed. In other embodiments, the excitation coils can be wound on the non-sensitive axes of the magnetic core (such as the two short axes of the above-mentioned racetrack-shaped magnetic core).

[0110] In this embodiment, each sensitive unit has multiple induction coils, that is, the induction coils include multiple spiral coils, and the multiple spiral coils are connected in parallel. The multiple induction coils are wound around the middle of the two sensitive axes of the magnetic core. The conductor channel is located in the gap between the sensitive axes of the two sensitive units.

[0111] In this embodiment, each sensitive unit includes a pair of input ports 4 and a pair of output ports 5. The input port 4 is connected to the excitation coil 2 for applying an excitation signal to the excitation coil. The output port 5 is connected to the induction coil 3 for outputting the induction signal of the induction coil. In other embodiments, the number of input ports and output ports of each sensitive unit can be set according to actual needs. Each sensitive unit can be set with only one pair of input ports, or two or more pairs of input ports and two or more pairs of output ports.

[0112] In this embodiment, a conductor interface is respectively provided at both ends of each conductor channel, and two conductor channels correspond to four conductor interfaces (not shown in the drawings).

[0113] In this embodiment, the material of the magnetic core of the sensitive unit can be soft magnetic materials such as Permalloy material, amorphous material or nanocrystalline alloy material. The material of the excitation coil and the induction coil can be a single metal material or an alloy material. The material of the conductor channel is a metal or metal alloy with good electrical conductivity, such as copper, aluminum, aluminum alloy, silver alloy, etc., and liquid copper can also be selected.

[0114] The sensitive unit in the embodiment of the present invention is a parallel fluxgate structure in which an induction coil is wound around a magnetic core, which is more sensitive to tiny changes in magnetic flux and has a higher chip detection sensitivity. The conductor channel of the present invention is sandwiched between two sensitive units to form differential detection, which has high detection accuracy and strong anti-interference ability. The current sensor chip proposed in the present invention can not only be used for leakage current detection, but also meet various high-precision, high-bandwidth AC and DC current detection requirements from milliamperes to amperes.

[0115] In addition, the fluxgate current sensor chip of the present invention can adopt MEMS technology, the entire manufacturing process has strong fluidity, high chip yield and good consistency, and the wire to be tested is integrated between two fluxgate sensitive units to form a differential detection structure. There is no need to use a magnetic focusing ring structure, which significantly reduces the cost of the sensor. The chip is small in size and light in weight, and is easy to integrate and install.

[0116] The embodiment of the present invention also provides a method for manufacturing the fluxgate current sensor chip. For the fluxgate current sensor chip with a thin conductor channel cross-section thickness in the first embodiment, the following two methods based on MEMS technology are provided.

[0117] Reference Figure 7 , the first method includes the following steps:

[0118] 1) Prepare wafers: prepare two groups of wafers, each group of wafers includes two wafers, each wafer has two surfaces, and the wafer material can be silicon or silicon on insulator.

[0119] 2) Etching coil grooves and core grooves: For the two wafers in each group of wafers, a coil groove is etched on one surface of the first wafer, a core groove is etched on the first surface of the second wafer, and a coil groove is etched on the second surface of the second wafer.

[0120] 3) Deposition of insulating layer: Insulating material is deposited on the inner surface of the core slot and coil slot of each wafer to form an isolation insulating layer. The material of the isolation insulating layer can be silicon dioxide, silicon carbide or polyimide.

[0121] 4) Fabricating a conductor channel: forming a half-cavity structure corresponding to the conductor channel on one of the wafers in one group of wafers, and forming a half-cavity structure corresponding to the conductor channel on one of the wafers in another group of wafers.

[0122] 5) Placing the magnetic core: For each group of wafers, place the prefabricated magnetic core in the magnetic core slot of the second wafer. The magnetic core can be obtained by cutting soft magnetic material strips such as Permalloy, amorphous or nanocrystalline, or by stacking magnetic core materials and then machining them.

[0123] 6) Making a protective layer: A protective layer is formed on the surface of the magnetic core. The material of the protective layer can be silicon, silicon dioxide, or resin (BCB), polymethyl methacrylate / organic glass (PMMA), polyimide and other polymers.

[0124] 7) Wafer bonding: For each group of wafers, the first wafer in the group is bonded with the second wafer to form a closed solenoid coil slot wound on the magnetic core; the two groups of wafers are bonded so that the half-cavity structures of the corresponding conductor channels in the two groups of wafers are formed into an overall cavity structure of the corresponding conductor channel.

[0125] 8) Filling metal: Fill the closed coil slots in each set of wafers with liquid coil material to form a closed coil wound around the magnetic core, thus obtaining two sets of wafers as sensitive units; the coil material can be a single metal material or an alloy material;

[0126] Conductive material is filled in the overall cavity structure of the corresponding conductor channel between the two groups of wafers to form a conductor channel between the two groups of wafers. The conductor material can be liquid copper, or other metal or metal alloy materials with good conductivity. The two groups of wafers as sensitive units and the conductor channel between the two groups of wafers constitute a group of fluxgate current sensor chips.

[0127] 9) Slicing: Slice the filled wafer to obtain multiple individual fluxgate current sensor chips.

[0128] The second method includes the following steps:

[0129] 1) Prepare wafers: prepare two groups of wafers, each group of wafers includes two wafers, each wafer has two surfaces, and the wafer material can be silicon or silicon on insulator.

[0130] 2) Etching coil grooves and core grooves: For the two wafers in each group of wafers, a coil groove is etched on one surface of the first wafer, a core groove is etched on the first surface of the second wafer, and a coil groove is etched on the second surface of the second wafer.

[0131] 3) Deposition of insulating layer: Insulating material is deposited on the inner surface of the core slot and coil slot of each wafer to form an isolation insulating layer. The material of the isolation insulating layer can be silicon dioxide, silicon carbide or polyimide.

[0132] 4) Fabricating a conductor channel: forming an overall cavity structure corresponding to the conductor channel on any one of the two groups of wafers.

[0133] 5) Placing the magnetic core: For each group of wafers, place the prefabricated magnetic core in the magnetic core slot of the second wafer. The magnetic core can be obtained by cutting soft magnetic material strips such as Permalloy, amorphous or nanocrystalline, or by stacking magnetic core materials and then machining them.

[0134] 6) Making a protective layer: A protective layer is formed on the surface of the magnetic core. The material of the protective layer can be silicon, silicon dioxide, or polymers such as BCB, PMMA, and polyimide.

[0135] 7) Wafer bonding: For each group of wafers, the first wafer in the group is bonded with the second wafer to form a closed solenoid coil slot wound on the magnetic core; two groups of wafers are bonded so that the overall cavity structure of the corresponding conductor channel on one of the wafers is located between the two groups of wafers.

[0136] 8) Filling metal: Fill the closed coil slots in each group of wafers with liquid coil material to form a closed coil wound around the magnetic core, thereby obtaining two groups of wafers as sensitive units; the coil material can be a single metal material or an alloy material.

[0137] Conductive material is filled in the overall cavity structure of the corresponding conductor channel between the two groups of wafers to form a conductor channel between the two groups of wafers. The conductor material can be liquid copper or other metal materials with good conductivity. The two groups of wafers as sensitive units and the conductor channel between the two groups of wafers constitute a group of fluxgate current sensor chips.

[0138] 9) Slicing: Slice the filled wafer to obtain multiple individual fluxgate current sensor chips.

[0139] In the first method and the second method, before the conductor material is filled in the overall cavity structure corresponding to the conductor channel, according to the chip design requirements, the inner surface of the overall cavity structure corresponding to the conductor channel can be filled with an insulating material to form an isolation insulating layer. The material of the isolation insulating layer can be silicon dioxide, polyimide, or SU8 / BCB photoresist material.

[0140] For the fluxgate current sensor chip with a thicker conductor channel cross-section in the second embodiment, the following two method steps based on MEMS technology are provided.

[0141] Reference Figure 8 , the first method includes the following steps:

[0142] 1) Prepare wafers: Prepare three groups of wafers. Each group of wafers includes two wafers. Each wafer has two surfaces. The wafer material can be silicon or silicon on insulator.

[0143] 2) Etching coil grooves and magnetic core grooves: select the first group of wafers and the second group of wafers in the three groups of wafers, and for two wafers in the first group of wafers and two wafers in the second group of wafers, etch a coil groove on one surface of the first wafer, etch a magnetic core groove on the first surface of the second wafer, and etch a coil groove on the second surface of the second wafer.

[0144] 3) Deposition of insulating layer: Insulating material is deposited on the inner surfaces of the core slots and coil slots of the first group of wafers and the second group of wafers to form an isolation insulating layer. The material of the isolation insulating layer may be silicon dioxide, silicon carbide or polyimide.

[0145] 4) Placing the magnetic core: For the first group of wafers and the second group of wafers, place the prefabricated magnetic core in the magnetic core slot of the second wafer of each group of wafers; the magnetic core can be obtained by cutting soft magnetic material strips such as Permalloy, amorphous or nanocrystalline, or by stacking magnetic core materials and then machining them.

[0146] 5) Wafer bonding: For the first group of wafers and the second group of wafers, the first wafer in each group of wafers is bonded with the second wafer to form a closed coil slot wound on the magnetic core.

[0147] 6) Filling the coil: filling the closed coil slots in the first group of wafers and the second group of wafers with liquid coil material to form a closed coil wound around the magnetic core, thereby obtaining two groups of wafers containing sensitive units.

[0148] 7) Making a protective layer: A protective layer is formed on the surface of each group of wafers containing the magnetic core. The material of the protective layer can be silicon, silicon dioxide, or polymers such as BCB, PMMA, and polyimide.

[0149] 8) Fabricating a conductor channel: forming an overall cavity structure corresponding to the conductor channel on each wafer of the third group of wafers.

[0150] 9) Filling conductor: Fill the overall cavity structure of the corresponding conductor channel on the third group of wafers with conductor material to form a conductor channel; the conductor material can be liquid copper, or other metal or metal alloy materials with good conductive properties.

[0151] 10) Wafer bonding: The three groups of wafers are bonded so that the third group of wafers is located between the first group of wafers and the second group of wafers. The first group of wafers and the second group of wafers as sensitive units and the third group of wafers as conductor channels form a set of fluxgate current sensor chips. The bonding method is not limited to wafer bonding, forming a sandwich structure in which the conductor channel is integrated between two fluxgate sensitive units.

[0152] 11) Slicing: Slice the filled wafer to obtain multiple individual fluxgate current sensor chips.

[0153] The second method includes the following steps:

[0154] 1) Prepare wafers: Prepare three groups of wafers. Each group of wafers includes two wafers. Each wafer has two surfaces. The wafer material can be silicon or silicon on insulator.

[0155] 2) Etching coil grooves and magnetic core grooves: select the first group of wafers and the second group of wafers in the three groups of wafers, and for two wafers in the first group of wafers and two wafers in the second group of wafers, etch a coil groove on one surface of the first wafer, etch a magnetic core groove on the first surface of the second wafer, and etch a coil groove on the second surface of the second wafer.

[0156] 3) Deposition of insulating layer: Insulating material is deposited on the inner surfaces of the core slots and coil slots of the first group of wafers and the second group of wafers to form an isolation insulating layer. The material of the isolation insulating layer may be silicon dioxide, silicon carbide or polyimide.

[0157] 4) Placing the magnetic core: For the first group of wafers and the second group of wafers, place the prefabricated magnetic core in the magnetic core slot of the second wafer of each group of wafers; the magnetic core can be obtained by cutting soft magnetic material strips such as Permalloy, amorphous or nanocrystalline, or by stacking magnetic core materials and then machining them.

[0158] 5) Wafer bonding: For the first group of wafers and the second group of wafers, the first wafer in each group of wafers is bonded with the second wafer to form a closed coil slot wound on the magnetic core.

[0159] 6) Filling the coil: filling the closed coil slots in the first group of wafers and the second group of wafers with liquid coil material to form a closed coil wound around the magnetic core, thereby obtaining two groups of wafers containing sensitive units.

[0160] 7) Making a protective layer: A protective layer is formed on the surface of each group of wafers containing the magnetic core. The material of the protective layer can be silicon, silicon dioxide, or resin (BCB), polymethyl methacrylate / organic glass (PMMA), polyimide and other polymers.

[0161] 8) Fabrication of conductor channel: A semi-cavity structure corresponding to the conductor channel is formed on one of the wafers in the third group of wafers, and a semi-cavity structure corresponding to the conductor channel is formed on another wafer in the third group of wafers. When the two wafers are combined, a complete conductor channel structure is obtained.

[0162] 9) Filling conductors: Filling the cavity structures of the corresponding conductor channels of the third group of wafers with conductor materials to form conductor channels; the conductor materials may be liquid copper or other metal materials with good conductivity.

[0163] 10) Wafer bonding: The three groups of wafers are bonded so that the third group of wafers is located between the first group of wafers and the second group of wafers. The first group of wafers and the second group of wafers as sensitive units and the third group of wafers as conductor channels constitute a set of fluxgate current sensor chips. The bonding method is not limited to wafer bonding, forming a sandwich structure in which the conductor channel is integrated between two fluxgate sensitive units.

[0164] 11) Slicing: Slice the filled wafer to obtain multiple individual fluxgate current sensor chips.

[0165] The plurality of separate fluxgate current sensor chips are packaged, and the packaged chips include at least one pair of input / output interfaces and at least one pair of conductor interfaces for accessing the current to be measured.

[0166] In the first method and the second method, before filling the conductor material in the cavity structure corresponding to the conductor channel, according to the chip design requirements, the inner surface of the cavity structure corresponding to the conductor channel can be filled with an insulating material to form an isolation insulating layer. The material of the isolation insulating layer can be silicon dioxide, polyimide, or SU8 / BCB photoresist material.

[0167] The fluxgate current sensor chip provided in the above-mentioned first embodiment includes one conductor channel, one conductor channel corresponds to two conductor interfaces, and is a single-line integrated fluxgate current sensor chip.

[0168] The fluxgate current sensor chip provided in the above-mentioned second embodiment includes two conductor channels, and the two conductor channels correspond to four conductor interfaces, which is a two-wire integrated fluxgate current sensor chip.

[0169] The fluxgate current sensing chip provided by the present invention comprises at least two conductor interfaces after packaging, and the chip can be applied to open-loop detection of currents ranging from milliampere to ampere and high-precision, high-bandwidth closed-loop detection. For open-loop current detection, a single-wire integrated fluxgate current sensing chip comprising two conductor interfaces can be used, or a two-wire integrated fluxgate current sensing chip comprising four conductor interfaces can be used. For closed-loop current detection, a two-wire integrated fluxgate current sensing chip comprising four conductor interfaces is selected. During closed-loop detection, only two conductor interfaces of the two-wire integrated fluxgate current sensing chip are selected, and the current to be measured is connected to the other two conductor interfaces, and the feedback circuit is connected.

[0170] For a single-phase current to be measured, a single-wire integrated fluxgate current sensor chip or a dual-wire integrated fluxgate current sensor chip is used for open-loop detection, or a dual-wire integrated fluxgate current sensor chip is used for closed-loop detection.

[0171] For the three-phase current to be measured, four single-line integrated fluxgate current sensor chips or two-line integrated fluxgate current sensor chips are used to perform open-loop or closed-loop detection.

[0172] The single-line integrated fluxgate current sensor chip includes a conductor channel, and the conductor channel corresponds to two conductor interfaces. The conductor interface corresponding to the conductor channel is selected to be connected to a single busbar to realize open-loop detection of leakage current or busbar current.

[0173] The dual-wire integrated fluxgate current sensor chip includes two conductor channels, each conductor channel corresponds to two conductor interfaces, and the conductor interfaces corresponding to the two conductor channels are respectively connected to the L line and the N line to realize open-loop detection of the residual current.

[0174] For the two-wire integrated fluxgate current sensor chip, select the conductor interface corresponding to one of the two conductor channels to connect to the current to be measured, and connect the conductor interface corresponding to the other conductor channel to the feedback circuit to achieve closed-loop detection of the current to be measured. For the three-phase current to be measured, four two-wire integrated fluxgate current sensor chips are used, and the conductor interface corresponding to one of the conductor channels of each two-wire integrated fluxgate current sensor chip is connected to the A, B, C and N lines respectively, and the conductor interface corresponding to the other conductor channel of each two-wire integrated fluxgate current sensor chip is connected to the feedback circuit to achieve closed-loop detection of the three-phase current to be measured.

[0175] Specifically, for application scenarios such as insulator string leakage current, arrester leakage current, core clamp grounding current, transformer bushing dielectric loss and ground fault detection, single-line integrated fluxgate current sensor chips can be used. Fig. 9 As shown, the current to be measured Ip flows into the chip pin (i.e., conductor interface) 11 and flows out from pin 12; you can also choose to use a two-wire integrated fluxgate current sensor chip for closed-loop detection, the current to be measured Ip flows into the chip pin 21 and flows out from pin 22, and pins 31 and 32 are connected to the feedback circuit.

[0176] For residual current monitoring applications in power equipment such as charging piles, inverters, and energy meters, if single-phase measurement is required, a two-wire integrated fluxgate current sensor chip can be used. Fig.10As shown, the current of the L line to be measured flows into the pin 21 of the chip and flows out of the pin 22, and the current of the N line to be measured flows into the pin 31 of the chip and flows out of the pin 32; you can also choose to use two single-line integrated fluxgate current sensor chips to connect to the L line and the N line respectively, the current flows into the pin 11 of each chip and flows out from the pin 12, and the leakage current is calculated by measuring the current value on each line, which helps to analyze the cause of the current leakage; you can also choose to use two double-line integrated fluxgate current sensor chips to connect to the L line and the N line respectively, the current flows into the pin 21 of each chip and flows out from the pin 22, the feedback circuit is connected from pins 31 and 32, and the leakage current is calculated by closed-loop measurement of the current value on each line. For three-phase measurement, you can choose to use four single-wire integrated fluxgate current sensor chips to connect to the A, B, C and N lines respectively. The current flows into pin 11 of each chip and flows out from pin 12. The leakage current is calculated by measuring the current value on each line. You can also choose to use four two-wire integrated fluxgate current sensor chips to connect to the A, B, C and N lines respectively. The current flows into pin 21 of each chip and flows out from pin 22. The feedback circuit is connected from pins 31 and 32. The leakage current is calculated by closed-loop measurement of the current value on each line.

[0177] The fluxgate current sensor chip and the manufacturing method thereof proposed in the present invention have the following advantages:

[0178] (1) The chip adopts the fluxgate principle, has high measurement accuracy, and can meet the requirements of AC and DC current measurement. The chip integrates a conductor channel to avoid installation errors;

[0179] (2) The chip uses two sensitive units and a conductor channel between the two sensitive units to form a differential structure, which can suppress common-mode interference and has strong resistance to external magnetic field interference;

[0180] (3) The chip is manufactured entirely using MEMS technology, which can realize mass production of current sensor chips. The entire production process has strong fluidity, standardized process flow, clean and pollution-free process, high chip yield and good consistency;

[0181] (4) The chip adopts a differential detection structure consisting of two sensitive units, which does not require the use of a magnetic ring structure, significantly reducing the cost of the sensor. The chip is small in size and light in weight, making it easy to integrate and install.

[0182] (5) The chip can realize both open-loop and closed-loop current detection modes, and can meet various high-precision and high-bandwidth current detection requirements from milliamperes to amperes;

[0183] (6) When the chip is used to measure the residual current of equipment such as charging piles and electric energy meters, it can accurately measure the current value on each wire, locate the current leakage fault point and help analyze the cause of the current leakage.

[0184] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, a variety of simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction, and as long as the combination does not violate the concept of the embodiments of the present invention, it should also be regarded as the content disclosed in the embodiments of the present invention.

Claims

1. A method for manufacturing a fluxgate current sensor chip, characterized in that: The fluxgate current sensor chip comprises: a first sensitive unit, a second sensitive unit and at least one conductor channel between the first sensitive unit and the second sensitive unit, the first sensitive unit is located on the upper surface of the conductor channel, the second sensitive unit is located on the lower surface of the conductor channel, the first sensitive unit and the second sensitive unit both comprise a magnetic core and a coil, the coil comprises an excitation coil and an induction coil, the excitation coil and the induction coil are wound on the magnetic core, and the first sensitive unit and the second sensitive unit constitute a differential detection structure; The manufacturing method of the fluxgate current sensor chip comprises: preparing two groups of wafers, each group of wafers including two wafers; For two wafers in each group of wafers, a coil groove is etched on one surface of a first wafer, a magnetic core groove is etched on a first surface of a second wafer, and a coil groove is etched on a second surface of the second wafer; Forming a half-cavity structure corresponding to the conductor channel on one of the wafers in one group of wafers, and forming a half-cavity structure corresponding to the conductor channel on one of the wafers in another group of wafers; For each set of wafers, the prefabricated cores are placed in the core slots of the second wafer; For each group of wafers, a first wafer in the group of wafers is combined with a second wafer to form a closed coil slot wound on a magnetic core; Combining the two groups of wafers so that the half-cavity structures corresponding to the conductor channels in the two groups of wafers form an overall cavity structure corresponding to the conductor channel; Filling coil materials in the closed coil slots in each group of wafers to form a closed coil wound around a magnetic core, thereby obtaining two groups of wafers as sensitive units; Conductive material is filled in the overall cavity structure of the corresponding conductor channel between the two groups of wafers to form a conductor channel between the two groups of wafers. The two groups of wafers as sensitive units and the conductor channel between the two groups of wafers constitute a group of fluxgate current sensor chips.

2. A method for manufacturing a fluxgate current sensor chip, characterized in that: The fluxgate current sensor chip comprises: a first sensitive unit, a second sensitive unit and at least one conductor channel between the first sensitive unit and the second sensitive unit, the first sensitive unit is located on the upper surface of the conductor channel, the second sensitive unit is located on the lower surface of the conductor channel, the first sensitive unit and the second sensitive unit both comprise a magnetic core and a coil, the coil comprises an excitation coil and an induction coil, the excitation coil and the induction coil are wound on the magnetic core, and the first sensitive unit and the second sensitive unit constitute a differential detection structure; The manufacturing method of the fluxgate current sensor chip comprises: preparing two groups of wafers, each group of wafers including two wafers; For two wafers in each group of wafers, a coil groove is etched on one surface of a first wafer, a magnetic core groove is etched on a first surface of a second wafer, and a coil groove is etched on a second surface of the second wafer; forming an overall cavity structure corresponding to the conductor channel on one of the two groups of wafers; For each set of wafers, the prefabricated cores are placed in the core slots of the second wafer; For each group of wafers, a first wafer in the group of wafers is combined with a second wafer to form a closed coil slot wound on a magnetic core; Combining the two groups of wafers so that the overall cavity structure of the corresponding conductor channel on one of the wafers is located between the two groups of wafers; Filling coil materials in the closed coil slots in each group of wafers to form a closed coil wound around a magnetic core, thereby obtaining two groups of wafers as sensitive units; Conductive material is filled in the overall cavity structure of the corresponding conductor channel between the two groups of wafers to form a conductor channel between the two groups of wafers. The two groups of wafers as sensitive units and the conductor channel between the two groups of wafers constitute a group of fluxgate current sensor chips.

3. The method for manufacturing a fluxgate current sensor chip according to claim 1 or 2, characterized in that: The method further comprises: Before placing the magnetic core in the magnetic core slot, forming an isolation insulating layer on the inner surface of the magnetic core slot; Before the coil groove is filled with the coil material, an isolation insulating layer is formed on the inner surface of the coil groove.

4. The method for manufacturing a fluxgate current sensor chip according to claim 1 or 2, characterized in that: The method further comprises: Before the conductor material is filled into the cavity structure corresponding to the conductor channel, an isolation insulating layer is formed on the inner surface of the cavity structure.

5. The method for manufacturing a fluxgate current sensor chip according to claim 3, characterized in that: The material of the isolation insulating layer is silicon dioxide, silicon carbide or polyimide.

6. The method for manufacturing a fluxgate current sensor chip according to claim 1 or 2, characterized in that: The method further comprises: After the prefabricated magnetic core is placed in the magnetic core groove, a protective layer is formed on the surface of the magnetic core.

7. The method for manufacturing a fluxgate current sensor chip according to claim 6, characterized in that: The material of the protective layer is silicon, silicon dioxide, resin, organic glass or polyimide.

8. A method for manufacturing a fluxgate current sensor chip, characterized in that: The fluxgate current sensor chip comprises: a first sensitive unit, a second sensitive unit and at least one conductor channel between the first sensitive unit and the second sensitive unit, the first sensitive unit is located on the upper surface of the conductor channel, the second sensitive unit is located on the lower surface of the conductor channel, the first sensitive unit and the second sensitive unit both comprise a magnetic core and a coil, the coil comprises an excitation coil and an induction coil, the excitation coil and the induction coil are wound on the magnetic core, and the first sensitive unit and the second sensitive unit constitute a differential detection structure; The manufacturing method of the fluxgate current sensor chip comprises: Prepare three groups of wafers, each group of wafers includes two wafers; Selecting a first group of wafers and a second group of wafers from the three groups of wafers, etching a coil groove on one surface of the first wafer, etching a magnetic core groove on a first surface of the second wafer, and etching a coil groove on a second surface of the second wafer for two wafers from the first group of wafers and two wafers from the second group of wafers; For the first group of wafers and the second group of wafers, placing the prefabricated magnetic core in the magnetic core slot of the second wafer of each group of wafers; The first wafer in each set of wafers is combined with the second wafer to form a closed coil slot wound on the magnetic core; Filling coil materials in closed coil slots in the first group of wafers and the second group of wafers to form closed coils wound around a magnetic core, thereby obtaining two groups of wafers containing sensitive units; forming an overall cavity structure corresponding to the conductor channel on each wafer of the third group of wafers; Filling the overall cavity structure of the corresponding conductor channels on the third group of wafers with a conductor material to form a conductor channel; The three groups of wafers are combined so that the third group of wafers is located between the first group of wafers and the second group of wafers. The first group of wafers and the second group of wafers as sensitive units and the third group of wafers as conductor channels constitute a group of fluxgate current sensor chips.

9. A method for manufacturing a fluxgate current sensor chip, characterized in that: The fluxgate current sensor chip comprises: a first sensitive unit, a second sensitive unit and at least one conductor channel between the first sensitive unit and the second sensitive unit, the first sensitive unit is located on the upper surface of the conductor channel, the second sensitive unit is located on the lower surface of the conductor channel, the first sensitive unit and the second sensitive unit both comprise a magnetic core and a coil, the coil comprises an excitation coil and an induction coil, the excitation coil and the induction coil are wound on the magnetic core, and the first sensitive unit and the second sensitive unit constitute a differential detection structure; The manufacturing method of the fluxgate current sensor chip comprises: Prepare three groups of wafers, each group of wafers includes two wafers; Selecting a first group of wafers and a second group of wafers from the three groups of wafers, etching a coil groove on one surface of the first wafer, etching a magnetic core groove on a first surface of the second wafer, and etching a coil groove on a second surface of the second wafer for two wafers from the first group of wafers and two wafers from the second group of wafers; For the first group of wafers and the second group of wafers, placing the prefabricated magnetic core in the magnetic core slot of the second wafer of each group of wafers; The first wafer in each set of wafers is combined with the second wafer to form a closed coil slot wound on the magnetic core; Filling coil materials in closed coil slots in the first group of wafers and the second group of wafers to form closed coils wound around a magnetic core, thereby obtaining two groups of wafers containing sensitive units; forming a half-cavity structure corresponding to the conductor channel on one of the wafers in the third group of wafers, and forming a half-cavity structure corresponding to the conductor channel on another wafer in the third group of wafers; Combining the two wafers of the third group so that the half-cavity structures corresponding to the conductor channels in the two wafers form an overall cavity structure corresponding to the conductor channels; Filling the overall cavity structure of the corresponding conductor channels on the third group of wafers with a conductor material to form a conductor channel; The three groups of wafers are combined so that the third group of wafers is located between the first group of wafers and the second group of wafers. The two conductor channels on the third group of wafers are combined into an integral conductor channel. The first group of wafers and the second group of wafers as sensitive units and the third group of wafers as a conductor channel constitute a group of fluxgate current sensor chips.

10. The method for manufacturing a fluxgate current sensor chip according to claim 8 or 9, characterized in that: The method further comprises: Before placing the magnetic core in the magnetic core slot, forming an isolation insulating layer on the inner surface of the magnetic core slot; Before the conductor material is filled into the cavity structure corresponding to the conductor channel, an isolation insulating layer is formed on the inner surface of the cavity structure.

11. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The method further comprises: Slicing the combined wafers to obtain multiple individual fluxgate current sensor chips; The individual fluxgate current sensor chip is packaged, and the packaged chip comprises at least one pair of input / output interfaces and at least one pair of conductor interfaces for accessing the current to be measured.

12. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The distance between the first sensitive unit and the upper surface of the conductor channel and the distance between the second sensitive unit and the lower surface of the conductor channel are equal.

13. The method for manufacturing a fluxgate current sensor chip according to claim 12, characterized in that: The magnetic field near the upper surface of the conductor channel sensed by the first sensitive unit and the magnetic field near the lower surface of the conductor channel sensed by the second sensitive unit are equal in magnitude and opposite in direction.

14. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The exciting coil and the induction coil are the same set of spiral coils, and the axis of the spiral coil wound around the magnetic core serves as the sensitive axis of the sensitive unit.

15. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The excitation coil includes at least one set of spiral coils, and the induction coil includes at least one set of spiral coils.

16. The method for manufacturing a fluxgate current sensor chip according to claim 15, characterized in that: The spiral coil as the induction coil is wound on the sensitive axis of the magnetic core, and the spiral coil as the excitation coil is wound on the non-sensitive axis of the magnetic core.

17. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The excitation coil includes a plurality of spiral coils, and the plurality of spiral coils as the excitation coils are connected in series.

18. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The induction coil includes a plurality of spiral coils, and the plurality of spiral coils serving as the induction coils are connected in parallel.

19. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The magnetic core of each sensitive unit is in any of the following shapes: rod, rectangle, ring, racetrack, and hexagon. The structure of the magnetic core is an open structure or a closed structure.

20. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The material of the conductor channel is metal or metal alloy.

21. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The cross-sectional shape of the conductor channel is rectangular, elliptical or polygonal.

22. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The conductor channel is located in the gap between the sensitive axes of the two sensitive units.

23. The method for manufacturing a fluxgate current sensor chip according to claim 14, characterized in that: Each sensitive unit includes at least one pair of input ports, the input ports are connected to the excitation coil and are used to apply an excitation signal to the excitation coil; The input port also serves as an output port for outputting the sensing signal of the sensitive unit.

24. The method for manufacturing a fluxgate current sensor chip according to claim 15, characterized in that: Each sensitive unit includes at least one pair of input ports and at least one pair of output ports; The input port is connected to the excitation coil and is used to apply an excitation signal to the excitation coil; The output port is connected to the induction coil and is used for outputting the induction signal of the induction coil.

25. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: The number of conductor channels is two.

26. The method for manufacturing a fluxgate current sensor chip according to claim 25, characterized in that: The two conductor channels are arranged transversely to the sensitive axis of the magnetic core.

27. The method for manufacturing a fluxgate current sensor chip according to claim 1, 2, 8 or 9, characterized in that: A conductor interface is respectively provided at both ends of each conductor channel.

28. An application method of a fluxgate current sensor chip, wherein the fluxgate current sensor chip is a fluxgate current sensor chip obtained by the manufacturing method of the fluxgate current sensor chip according to claim 1, 2, 8 or 9, and the fluxgate current sensor chip comprises two conductor channels, each conductor channel corresponds to two conductor interfaces, and is characterized in that: The application method of the fluxgate current sensor chip includes: A conductor interface corresponding to one of the conductor channels of the fluxgate current sensor chip is selected to be connected to the current to be measured, and a conductor interface corresponding to another conductor channel is connected to a feedback circuit to achieve closed-loop detection of the current to be measured.

29. The application method of the fluxgate current sensor chip according to claim 28, characterized in that: The method further comprises: For the three-phase current to be measured, four fluxgate current sensor chips are used, and the conductor interface corresponding to one conductor channel of each fluxgate current sensor chip is connected to the A, B, C and N lines respectively, and the conductor interface corresponding to the other conductor channel of each fluxgate current sensor chip is connected to the feedback circuit to realize closed-loop detection of the three-phase current to be measured.

30. An application method of a fluxgate current sensor chip, wherein the fluxgate current sensor chip is a fluxgate current sensor chip obtained by the manufacturing method of the fluxgate current sensor chip according to claim 1, 2, 8 or 9, wherein the fluxgate current sensor chip comprises a conductor channel corresponding to two conductor interfaces, characterized in that: The application method of the fluxgate current sensor chip includes: The conductor interface corresponding to the conductor channel of the fluxgate current sensor chip is selected to be connected to a single busbar to realize open-loop detection of leakage current or busbar current.

31. An application method of a fluxgate current sensor chip, wherein the fluxgate current sensor chip is a fluxgate current sensor chip obtained by the manufacturing method of the fluxgate current sensor chip according to claim 1, 2, 8 or 9, and the fluxgate current sensor chip comprises two conductor channels, each conductor channel corresponds to two conductor interfaces, and is characterized in that: The application method of the fluxgate current sensor chip includes: The conductor interfaces corresponding to the two conductor channels of the fluxgate current sensor chip are respectively connected to the L line and the N line to realize open-loop detection of the residual current.

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