Packaging Structure and Assembly Method of a Dual-Range Fluxgate Current Sensor

Abstract

The present invention discloses a packaging structure and an assembly method for a dual-range fluxgate current sensor. The packaging structure includes a packaging shell made of permalloy, which can shield magnetic field interference brought by the external environment and encapsulates two annular detection coils with a large range and a small range, a signal processing board, and a power circuit board. The assembly method adopts the packaging structure of the dual-range fluxgate current sensor, reasonably plans the assembly space, and precisely assembles each component on the premise of preventing signal crosstalk to ensure the stability of current detection. The packaging structure and the assembly method of the current sensor of the present invention can meet the detection requirements of the fluxgate current sensor for wide range, high resolution, and high linearity, and at the same time make the overall sensor more integrated, miniaturized, and portable.

Description

Technical Field

[0001] The present invention relates to the technical fields of fluxgate technology and current sensors, and specifically to a packaging structure and assembly method for a dual-range fluxgate current sensor. Background Art

[0002] Existing detection probes based on fluxgate sensors are divided into structures such as single-rod type, double-rod type, and ring type. Among them, the magnetic core of the ring-shaped fluxgate probe is a closed magnetic circuit. The ring-shaped coil has good symmetry and structural balance, and the stress received by the magnetic core is evenly distributed. Therefore, the ring-shaped fluxgate probe has less noise and higher detection sensitivity. In this design, a fluxgate detection probe with a double-ring structure is adopted. The excitation coils wound around the double-ring magnetic cores have opposite directions, which makes the fundamental wave and odd harmonics of the output signal cancel each other out to a great extent, demonstrating the powerful superiority of the double-ring structure.

[0003] Currently, all fluxgate current sensors on the market use a single ring-shaped probe, and the packaging design only encapsulates a single ring-shaped coil inside, which is not suitable for the packaging of two coils with dual ranges. The signal processing circuit and the power supply circuit both adopt an external connection form, resulting in a relatively large volume of the sensor and inconvenient use. To solve the above problems, the present invention designs a housing that can encapsulate two ring-shaped probes for dual-range current detection, and at the same time designs the signal processing board as two vertically overlapping ring-shaped multi-layer boards nested in the packaging design. In addition, considering problems such as external magnetic field interference, signal anti-crosstalk between the large-range and small-range detection probes, and precise positioning of the signal processing board and the probe, the present invention adds more detailed processing in the design of the packaging structure, designs fixed hole columns and separation layers, and at the same time designs a corresponding assembly method. The overall packaging design can enable the internal current sensor to perform high-resolution, high-linearity, and wide-range current detection, and at the same time make the entire sensor more integrated, unified, beautiful, miniaturized, and portable.

[0004] There are also some cases of fluxgate current sensors at present. For example, the patent number is CN208984703U, and the name is an integrated high-precision fluxgate current sensor. This utility model patent designs a packaging structure for a fluxgate ring detection coil and adds a power indicator light, a zero point button, a signal interface, etc.; however, its design has only one ring coil, and only the ring coil is encapsulated inside the shell. The utility model patent with the patent number CN210465525U designs an open-type fluxgate current sensor. This patent designs an openable packaging structure, which does not require cutting the wire to pass through the sensor for detection, making the application scenario of the sensor wider and more convenient to use. Combining the above two patents, it can be known that the existing designs all stay at designing a ring coil and externally connecting a circuit through a data interface for power supply and signal processing, which makes the design of the whole system bulky, the circuit connection complex, and the existing designs can only meet one of the high resolution and wide range.

[0005] By comparing the existing patents with the present invention, it can be found that the present design has obvious technical advantages. The small-volume packaging structure can encapsulate two probes of different sizes, enabling the fluxgate current sensor of the present invention to simultaneously meet a resolution of 1 μA and a range of 1000 A; in addition, the assembly method of the present invention can embed the power supply circuit board and the signal processing board therein, eliminating the need to externally connect a large-volume signal processing box. The fluxgate current sensor involved in the technology of the present invention not only realizes the measurement of high resolution, high precision, and high linearity of the current sensor, but also is more miniaturized, portable, and more flexible in application. Summary of the Invention

[0006] The purpose of the present invention is to design a sensor packaging structure and a corresponding assembly method for high-precision dual-range fluxgate current detection; the packaging structure made of permalloy in the present invention can effectively shield external interference, and can integrate two probes, a processing circuit board, and a power supply circuit board in one package at the same time, and the packaged product is convenient for testing and use; the dual-range detection probe of this design can detect both large currents and weak currents in the microampere level.

[0007] A packaging structure of a dual-range fluxgate current sensor includes a housing main body, a housing cover, heat dissipation mesh holes, and a soft magnetic shielding plate;

[0008] The housing main body and the housing cover are made of permalloy, and the housing cover tightly covers the housing main body;

[0009] Heat dissipation mesh holes and a 220V power supply line interface are provided on the side wall of the housing main body; a soft magnetic shielding plate for isolating the power supply circuit board from the ring detection probe is arranged inside the housing main body;

[0010] A large-current detection hole column and a small-current detection hole column are also arranged inside the shell main body; a ±12V power supply interface is opened on the soft magnetic shielding plate; a signal output port, a large opening and a small opening for assembling the large-current detection hole column and the small-current detection hole column are arranged on the shell cover.

[0011] Preferably, the shell main body and the shell cover are made of permalloy with a thickness of 0.5 mm to 2 mm. The length of the shell main body is 80 mm to 100 mm, the width is 30 mm to 50 mm, and the height is 100 mm to 130 mm.

[0012] Preferably, the heat dissipation mesh holes are distributed at the circumference of the top coil of the shell main body and around the power supply circuit board at the lower end of the back of the shell, and are respectively used for the heat dissipation of the energized coil and the power amplifier of the power supply circuit board.

[0013] Preferably, the soft magnetic shielding plate is a permalloy thin sheet with a thickness of 1 mm.

[0014] Preferably, the aperture of the large-current detection hole column is 20 mm to 40 mm, and the aperture of the small-current detection hole column is 3 mm to 6 mm. The hole column is made by 3D printing with photosensitive resin material or ceramic fiber material.

[0015] Adopting the above-mentioned packaging structure of the dual-range fluxgate current sensor, there is an assembly method of the dual-range fluxgate current sensor as follows. The specific steps are as follows:

[0016] The first step is to fixedly arrange the power supply circuit board on one side of the soft magnetic shielding plate inside the shell main body, lead out the input and output ends of the power supply, and set a 220V power supply line interface on the side wall of the shell main body corresponding to the input end of the power supply.

[0017] The second step is to split the signal processing board into two overlapping and nested bottom-layer annular plates and top-layer annular plates on the other side of the soft magnetic shielding plate inside the shell main body. First, embed the bottom-layer annular plate into the large-current detection hole column and then fix it inside the shell main body. Then, embed the large-range detection coil and the small-range detection coil into two corresponding large-current detection hole columns and small-current detection hole columns respectively. Then, connect the two detection coils to the circuit processing board by means of signal lines, and connect the power supply line on the power supply board to the circuit processing board. Then, embed the top-layer annular plate into the large-range current detection hole column and fix the top-layer annular plate on the bottom-layer annular plate. At this time, the large-range detection coil and the small-range detection coil are fixed between the two annular plates. Add permalloy thin sheets between the signal processing board and the large-range detection coil and between the two detection coils of the large and small ranges respectively for signal isolation to prevent mutual crosstalk.

[0018] The third step is to lead out the USART serial communication interface on the signal processing board, cover the cover tightly, align the signal output port on the cover with the USART serial communication interface, and complete the assembly of the dual-range fluxgate current sensor;

[0019] The fourth step is to insert the power cord into the 220V power cord interface, and use the data cable or wireless communication module to connect the sensor and the host computer. You only need to pass the measured wire through the corresponding detection hole column according to the measuring range, and you can read the detected current value in real time on the host computer.

[0020] The signal processing board and the power circuit board are fixedly connected to the shell body through threads.

[0021] The beneficial effects of the present invention are:

[0022] (1) The dual-range fluxgate current sensor packaging structure encapsulates two annular detection probes, a signal processing circuit board, and a power supply circuit board in one box, which is flexible, portable, convenient, and practical. In addition, the Permalloy metal shell can effectively shield the magnetic field interference caused by the external environment, making the measured current value more linear and accurate.

[0023] (2) The housing of the present invention encapsulates two annular detection probes, one with a large range and one with a small range, so that current detection can meet the requirements of a wide range and high resolution at the same time.

[0024] (3) The purposefully designed assembly method of the present invention can well fix the detection coil and ensure the stability of current detection. At the same time, the assembly is reasonable and meticulous, making the overall design more beautiful, miniaturized and portable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The current sensor packaging structure of the present invention;

[0026] Figure 2 This is an open cover internal diagram of the current sensor packaging structure of the present invention;

[0027] Figure 3 This is an exploded view of the current sensor package of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] like Figure 1 and Figure 2 As shown, a packaging structure of a dual-range fluxgate current sensor includes a housing body 1, a housing cover 2, a heat dissipation mesh 3 and a soft magnetic shielding plate 9;

[0030] In this embodiment, the housing main body 1 and the housing cover 2 are made of permalloy with a thickness of 0.5 mm to 2 mm. The length of the housing main body 1 is 80 mm to 100 mm, the width is 30 mm to 50 mm, and the height is 100 mm to 130 mm. The side lengths of each side are slightly larger than the side lengths of the periphery of the housing cover 2, allowing the housing cover to tightly cover the housing main body. Making the metal shielding housing with permalloy can effectively shield the magnetic field interference brought by the external environment.

[0031] Heat dissipation mesh holes 3 and 220V power supply line interfaces 6 are provided on the side wall of the housing main body 1. In this embodiment, the heat dissipation mesh holes 3 are located at the circumference of the top coil of the housing main body and around the power supply circuit board at the lower end of the back of the housing, respectively, for dissipating heat from the energized coil and the power amplifier of the power supply circuit board.

[0032] A soft magnetic shielding plate 9 is provided inside the housing main body 1. The soft magnetic shielding plate 9 is a permalloy thin sheet with a thickness of 1 mm, placed between the power supply circuit board and the current detection hole column, for isolating the power supply circuit board from the ring detection probe, thereby shielding the noise interference generated by the power supply circuit board.

[0033] Permalloy thin sheets are added between the signal processing board 13 and the large-range detection coil and between the two ring coils of the large and small ranges respectively for signal isolation to prevent mutual crosstalk;

[0034] A large current detection hole column 4 and a small current detection hole column 5 are also provided inside the housing main body 1. In this embodiment, the aperture of the large current detection hole column 4 is 20 mm to 40 mm, the length of the hole column for placing the large probe coil and the ring plate is 20 mm to 30 mm, and the hole column is made by 3D printing with photosensitive resin material or ceramic fiber material for detecting the thick wire carrying large current. The aperture of the small current detection hole column 5 is 3 mm to 6 mm, the length of the hole column for placing the small probe coil is 20 mm to 30 mm, and the hole column is made by 3D printing with photosensitive resin material or ceramic fiber material for detecting weak current.

[0035] ±12V power supply interfaces 8 are provided on the soft magnetic shielding plate 9 for leading out the output wire of the power supply circuit board to supply power to the signal processing board.

[0036] A signal output port 7 and large and small openings for assembling the large current detection hole column 4 and the small current detection hole column 5 are provided on the housing cover 2.

[0037] As Figure 3 shown, in this embodiment, four circular holes with a diameter of 3 mm are respectively opened at the rear end and the bottom end of the housing main body as fixed mounting holes 10 for fixing the signal processing board and the power supply circuit board respectively.

[0038] Adopting the above-mentioned packaging structure of the dual-range fluxgate current sensor, there is an assembly method for the dual-range fluxgate current sensor as follows. The specific steps are as follows:

[0039] First step, place the power circuit board 12 on one side of the soft magnetic shielding plate 9 inside the housing main body 1, fix the four corners of the power circuit board 12 with screws, lead out the input and output lines of the power supply, and set a 220V power supply line interface 6 on the side wall of the housing main body 1 corresponding to the input end of the power supply;

[0040] Second step, on the other side of the soft magnetic shielding plate 9 inside the housing main body 1, split the signal processing board 13 into a bottom-layer annular plate and a top-layer annular plate that are overlapped and nested; first embed the bottom-layer annular plate into the large-current detection hole column 4, and fix the four corners in the housing main body with copper columns; then embed the large-range detection coil 14 and the small-range detection coil 11 into two corresponding hole columns respectively; then connect the two detection coils to the circuit processing board by means of signal lines, and connect the power supply line on the power supply board to the circuit processing board; then embed the top-layer annular plate into the large-range current detection hole column, and fix the four corners on the bottom-layer annular plate with copper columns. At this time, the two annular coils are fixed between the two annular plates; add Permalloy thin sheets between the signal processing board 13 and the two annular coils of the large and small ranges respectively for signal isolation to prevent mutual crosstalk;

[0041] Third step, lead out the USART serial communication interface on the signal processing board 13, cover the cover tightly, align the signal output port on the cover with the USART serial communication interface, and complete the assembly of the dual-range fluxgate current sensor;

[0042] Fourth step, insert the power supply line into the 220V power supply line interface, connect the sensor and the upper computer by using a data line or a wireless communication module. Just pass the measured wire through the corresponding detection port according to the range, and the detected current value can be read in real time on the upper computer.

[0043] Enclose the two annular detection probes (the small-range detection coil 11 and the large-range detection coil 14), the signal processing circuit board 13 and the power circuit board 12 inside, shielding the external magnetic field interference and facilitating the test use; heat dissipation mesh holes are provided at the top and back for the heat dissipation of the energized coil and the power amplifier of the power circuit board respectively; a 220V power supply line interface is provided on the side wall of the housing, which can directly connect the 220V mains power to the input end of the power circuit board for system power supply, and insulating materials are arranged around the interface to ensure safety; a signal output port is provided in the middle of the housing cover for leading out the USART serial communication interface on the signal processing board, which can be directly connected to the upper computer or connected to a wireless communication module for data transmission. In order to meet the miniaturization of the sensor, the signal processing board is split into two annular plates and overlapped and nested, and the detection probe is fixed between the two plates.

[0044] The specific embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A packaging structure of a dual-range fluxgate current sensor, characterized in that: It includes a housing main body, a housing cover, heat dissipation mesh holes and a soft magnetic shielding plate; The housing main body and the housing cover are made of permalloy, and the housing cover tightly covers the housing main body; Heat dissipation mesh holes and a 220V power supply line interface are provided on the side wall of the housing main body; a soft magnetic shielding plate for isolating the power supply circuit board from the annular detection probe is arranged inside the housing main body; A large current detection hole column and a small current detection hole column are also arranged inside the housing main body; a ±12V power supply interface is opened on the soft magnetic shielding plate; a signal output port, large and small openings for assembling the large current detection hole column and the small current detection hole column are arranged on the housing cover.

2. The packaging structure of the dual-range fluxgate current sensor according to claim 1, characterized in that: The housing main body and the housing cover are made of permalloy with a thickness of 0.5mm - 2mm, and the length of the housing main body is 80mm - 100mm, the width is 30mm - 50mm, and the height is 100mm - 130mm.

3. The encapsulation structure of the dual-range fluxgate current sensor according to claim 1, characterized in that: The heat dissipation mesh holes are distributed at the circumference of the top coil of the housing main body and around the power supply circuit board at the lower end of the back of the housing, and are respectively used for the heat dissipation of the energized coil and the power amplifier of the power supply circuit board.

4. The packaging structure of the dual-range fluxgate current sensor according to claim 1, characterized in that: The soft magnetic shielding plate is a permalloy thin sheet with a thickness of 1mm.

5. The packaging structure of the dual-range fluxgate current sensor according to claim 1, characterized in that: The aperture of the large current detection hole column is 20mm - 40mm, the aperture of the small current detection hole column is 3mm - 6mm, and the hole column is 3D printed with photosensitive resin material or ceramic fiber material.

6. Adopt the packaging structure of the dual-range fluxgate current sensor as described in claim 1, and there is an assembly method for the dual-range fluxgate current sensor as follows, characterized in that: Specifically, it includes the following steps: First step, fix the power supply circuit board on one side of the soft magnetic shielding plate inside the housing main body, lead out the input and output ends of the power supply, and set a 220V power supply line interface on the side wall of the housing main body corresponding to the input end of the power supply; Second step, on the other side of the soft magnetic shielding plate inside the housing main body, split the signal processing board into two overlapping and nested bottom-layer annular plates and top-layer annular plates; first embed the bottom-layer annular plate into the large current detection hole column and then fix it inside the housing main body; Then embed the large-range detection coil and the small-range detection coil into two corresponding large current detection hole columns and small current detection hole columns respectively; then connect the two detection coils to the circuit processing board with signal lines, and connect the power supply line on the power supply board to the circuit processing board; then embed the top-layer annular plate into the large-range current detection hole column and fix the top-layer annular plate on the bottom-layer annular plate; at this time, the large-range detection coil and the small-range detection coil are fixed between the two annular plates; add permalloy thin sheets between the signal processing board and the large-range detection coil and between the two detection coils of the large and small ranges respectively for signal isolation to prevent mutual crosstalk; Third step, lead out the USART serial communication interface on the signal processing board, cover the cover tightly, align the signal output port on the cover with the USART serial communication interface, and complete the assembly of the dual-range fluxgate current sensor; Fourth step, insert the power supply line into the 220V power supply line interface, connect the sensor and the upper computer with a data line or a wireless communication module, and just pass the wire to be measured through the corresponding detection hole column according to the range, and the detected current value can be read in real time on the upper computer.

7. The encapsulation structure of the dual-range fluxgate current sensor according to claim 6, characterized in that: The signal processing board and the power supply circuit board are fixedly connected to the housing main body by threads.

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