A current sensor

Abstract

The application discloses a current sensor, and aims at solving the problem of low detection precision of the current sensor. The current sensor comprises a first shell and a second shell which are arranged in a laminated mode, a first magnetic component is packaged in the first shell, and a second magnetic component is packaged in the second shell; a detection assembly is arranged in the first magnetic component, a first space for a first busbar is formed in the middle of the first magnetic component, the first end of the first busbar is electrically connected with a circuit board after penetrating through the first space of the first magnetic component from the bottom to the top, a metering assembly is arranged in the second magnetic component, a second space for a second busbar is formed in the middle of the second magnetic component, the first space and the second space are arranged in alignment along the length direction, and the first end of the second busbar is electrically connected with the circuit board after penetrating through the second space and the first space from the bottom to the top in sequence. Through the design of the upper and lower split packaging structure, the detection precision is improved.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle charging safety protection technology, and more specifically, to a current sensor. Background Technology

[0002] In related technologies, on-board charging guns, as key equipment for electric vehicles, face increasingly stringent requirements for safety and functionality. Current sensors are the core detection devices for residual current protection and charging energy metering. Their detection accuracy, integration, and maintainability directly determine the safety performance and operational reliability of charging equipment. However, most residual current sensors only possess a single residual current detection function.

[0003] Technicians believe that although some manufacturers have launched modules that integrate leakage current detection and metering, they still use an integrated structure with overall potting, which has the following drawbacks: the heat and electromagnetic interference generated when the metering module carries current will directly affect the detection accuracy, resulting in low detection accuracy.

[0004] The above problems urgently need to be addressed.

[0005] The above background information does not imply that the applicant accepts it as prior art. Summary of the Invention

[0006] This invention overcomes the shortcomings of low detection accuracy in related technologies for current sensors and provides a current sensor that improves detection accuracy through a split-type packaging structure design.

[0007] This invention provides a current sensor, comprising: a circuit board, a first housing and a second housing stacked together, wherein a first magnetic component is encapsulated in the first housing and a second magnetic component is encapsulated in the second housing; The first magnetic component has a detection component inside, and a first space is formed in the middle of the first magnetic component for the first busbar to pass through. The first end of the first busbar passes through the first space of the first magnetic component from bottom to top and is electrically connected to the circuit board. The second magnetic component has a metering component inside. A second space is formed in the middle of the second magnetic component for the second busbar to pass through. The first space and the second space are aligned along the length direction. The first end of the second busbar passes through the second space and the first space from bottom to top and is electrically connected to the circuit board.

[0008] Optionally, the detection component includes a first magnetic core disposed inside the first magnetic component and circumferentially surrounding the first space. A first coil and a second coil are wound around the outside of the first magnetic core. The first magnetic component has a first hole for the lead wire of the first coil to extend out and a second hole for the lead wire of the second coil to extend out. The leads wires of the first coil and the second coil pass through the first hole and the second hole respectively and are electrically connected to the circuit board.

[0009] Optionally, the metering component includes a second magnetic core, which is disposed inside the second magnetic component and circumferentially surrounds the second space. A third coil for outputting current metering signals is wound around the second magnetic core. A third hole is opened on the second magnetic component for the lead wire of the third coil to extend out. The lead wire of the third coil passes through the third hole and is electrically connected to the pin header connector.

[0010] Optionally, the first magnetic component is ring-shaped, the first busbar is U-shaped, the first end of the first busbar is a neutral input port, the second end of the first busbar is a neutral output port connected to an external device, the second end of the first busbar extends along the length of the first magnetic component from the outside, and the end face of the second end of the first busbar is flush with the end face of the first end of the first busbar.

[0011] Optionally, the second magnetic component is ring-shaped, and the first magnetic component and the second magnetic component are coaxially arranged. The second busbar is U-shaped, with the first end of the second busbar being a live wire input port and the second end of the second busbar being a live wire output port connected to an external device. The second end of the second busbar extends along the length of the second magnetic component from the outside, and the end face of the second end of the second busbar is flush with the end face of the first end of the second busbar.

[0012] Optionally, the bottom of the first housing has a first groove for accommodating the bent portion at the bottom of the first busbar. The first groove is strip-shaped and has a fourth hole and a fifth hole for the first end and the second end of the first busbar to pass through, respectively. The bottom of the first housing also has a sixth hole and a seventh hole for the first end and the second end of the second busbar to pass through, respectively. And / or, the bottom of the second housing has a second groove for accommodating the bent portion at the bottom of the second busbar. The second groove is strip-shaped and has an eighth hole and a ninth hole for the first end and the second end of the second busbar to pass through, respectively.

[0013] Optionally, the sixth hole and the eighth hole are aligned along the length direction of the first housing and the second housing, and the seventh hole and the ninth hole are aligned along the length direction of the first housing and the second housing.

[0014] Optionally, the first housing is provided with a first seat for the first magnetic component to be fitted. The position of the first seat corresponds to the fourth hole and the sixth hole, and the fourth hole and the sixth hole are both through holes that penetrate the first seat. The side of the circuit board near the first housing abuts against the first seat, and the circuit board has a strip-shaped through hole at the position corresponding to the fourth hole and the sixth hole for the two to pass through.

[0015] Optionally, a second seat is provided on the inner wall of the second housing, and a third groove is provided in the second seat along the length direction of the second housing. The first end of the pin header connector is provided with a third seat that is inserted and engaged with the third groove. The first housing is also provided with a through hole for the pin header connector to pass through, and the second end of the pin header connector extends out of the first housing through the through hole.

[0016] Optionally, the second housing is provided with a fourth seat for the second magnetic component to be fitted. The position of the fourth seat corresponds to the position of the eighth hole, and the eighth hole is a through hole that penetrates the fourth seat. The end face of the fourth seat near the first housing abuts against the second housing. The sixth hole and the eighth hole are combined to form a through hole through which the first end of the second busbar passes.

[0017] Compared with the prior art, the beneficial effects of the present invention are: First, it adopts a split structure, placing the detection component and the metering component in separate settings. After potting, physical isolation can be achieved, reducing electromagnetic interference and thermal effects, and improving the accuracy of leakage current detection.

[0018] Secondly, the busbar structure runs through both the detection and metering components, which, while ensuring the electrical series connection between the detection and metering components, also reduces solder joints and leads, making the structure more compact and easier to assemble. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present invention.

[0020] Figure 2 This is an exploded view of the first embodiment of the present invention. Figure 1 .

[0021] Figure 3 This is an exploded view of the first embodiment of the present invention. Figure 2 .

[0022] Figure 4 This is a schematic diagram of the structure of the first magnetic component and the second magnetic component according to the first embodiment of the present invention.

[0023] Figure 5 This is a rear view of the first magnetic component according to the first embodiment of the present invention.

[0024] Figure 6 This is the first embodiment of the present invention. Figure 5 Schematic diagram of the cross section at point A in the middle.

[0025] Figure 7 This is a rear view of the second magnetic component according to the first embodiment of the present invention.

[0026] Figure 8 This is the first embodiment of the present invention. Figure 7 Schematic diagram of the cross section at point B.

[0027] In the picture: 1. First housing; 11. Fourth hole; 12. Fifth hole; 13. Sixth hole; 14. Seventh hole; 15. First seat; 16. First slot; 2. Second housing; 21. Eighth hole; 22. Ninth hole; 23. Second seat; 24. Third slot; 25. Fourth seat; 26. Fifth seat; 27. Second slot; 3. Circuit board; 31. Strip-shaped through hole; 4. First magnetic component; 41. First space; 42. First hole; 43. Second hole; 5. Pin header connector; 51. Third seat; 6. Second magnetic component; 61. Second space; 62. Third hole; 7. First busbar; 8. Second busbar; 9. Detection component; 91. First magnetic core; 92. First coil; 93. Second coil; 10. Metering component; 101. Second magnetic core; 102. Third coil. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Similarly, words such as "a" or "one" do not indicate a quantity limitation, but rather indicate the presence of at least one; "multiple" indicates two or more. Unless otherwise stated, words such as "before," "after," "below," and / or "above" are for illustrative purposes only and are not limited to a location or spatial orientation.

[0030] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0034] First Embodiment Please refer to Figures 1 to 4 This embodiment provides a current sensor.

[0035] This invention provides a current sensor, comprising: a circuit board 3, a first housing 1 and a second housing 2 stacked together, wherein a first magnetic component 4 is encapsulated in the first housing 1 and a second magnetic component 6 is encapsulated in the second housing 2; The first magnetic component 4 has a detection component 9 inside. A first space 41 is formed in the middle of the first magnetic component 4 for the first busbar 7 to pass through. The first end of the first busbar 7 passes through the first space 41 of the first magnetic component 4 from bottom to top and is electrically connected to the circuit board 3. The second magnetic component 6 has a metering component 10 inside. The second magnetic component 6 forms a second space 61 in the middle for the second busbar 8 to pass through. The first space 41 and the second space 61 are aligned along the length direction. The first end of the second busbar 8 passes through the second space 61 and the first space 41 from bottom to top and is then electrically connected to the circuit board 3.

[0036] Please refer to Figures 5 to 6 The detection component 9 includes a first magnetic core 91, which is located inside the first magnetic component 4 and surrounds the first space 41. A first coil 92 and a second coil 93 are wound around the first magnetic core 91. The first magnetic component 4 has a first hole 42 for the lead wire of the first coil 92 to extend out, and a second hole 43 for the lead wire of the second coil 93 to extend out. The lead wires of the first coil 92 and the second coil 93 pass through the first hole 42 and the second hole 43 respectively and are electrically connected to the circuit board 3.

[0037] For example, the first coil 92 is a feedback coil used to cancel the magnetic field generated by the primary current through the principle of magnetic balance. It has 40 turns wound on the first magnetic core 91. Its operation is based on the principle of magnetic balance current detection: the live wire current carried by the second busbar 8 and the neutral wire current carried by the first busbar 7 are equal in magnitude and opposite in direction under normal operating conditions. When a leakage fault occurs in the circuit, a current difference is generated between the live wire and the neutral wire. This leakage difference current will generate a differential mode induced magnetic field in the first magnetic core 91. After calculation and amplification, it controls the feedback coil to output a compensation current, generating a canceling magnetic field in the opposite direction, so that the first magnetic core 91 always maintains a state close to zero magnetic flux. The magnitude of the compensation current is proportional to the amplitude of the residual current on the primary side, thereby realizing the accurate detection of the residual current. The above-mentioned differential mode induced magnetic field is the net alternating magnetic field left when the magnetic field generated by the live wire and neutral wire current cannot be completely canceled when a leakage current difference occurs in the energized circuit. This magnetic field is different from the zero-flux common mode magnetic field after the two-phase current cancels each other during normal power supply. It can be captured by the magnetic core and the coil for leakage detection.

[0038] The second coil 93 is a self-test coil, used to apply a preset excitation current to complete the self-test of the detection link. It has two turns wound on the first magnetic core 91. Under normal operating conditions, no current flows through the self-test coil, it does not participate in the magnetic circuit operation, and does not affect the detection accuracy. After the preset excitation current is applied to the self-test coil, a differential-mode magnetic field corresponding to the residual current fault can be generated inside the first magnetic core, so that the detection component feels a magnetic flux change similar to the actual leakage current state, thereby realizing the functional integrity verification of the leakage current detection link. The device self-test can be completed without simulating a real leakage current fault.

[0039] In addition, the first magnetic core 91 is made of a high-permeability soft magnetic material. High-permeability soft magnetic materials refer to soft magnetic functional materials that have high initial permeability, low coercivity, and low hysteresis loss in a weak magnetic field environment. They can sensitively capture weak residual current magnetic fields and improve the accuracy of small current detection. Typical materials include permalloy, nanocrystalline alloy, and manganese-zinc ferrite.

[0040] The advantages of this setup are that it adopts a magnetic balance detection architecture, which can simultaneously cover AC and DC residual current detection, with high detection accuracy and fast response speed; the feedback coil and self-test coil are integrated into the first magnetic core 91 design, realizing the self-test function without occupying additional space, and can verify the integrity of the detection link online, improving the reliability of product operation and maintenance; the high permeability magnetic core ensures the ability to capture weak leakage current signals and lowers the detection lower limit.

[0041] Please refer to Figures 7 to 8 The metering component 10 includes a second magnetic core 101, which is located inside the second magnetic component 6 and surrounds the second space 61. A third coil 102 for outputting current metering signals is wound around the second magnetic core 101. A third hole 62 is opened on the second magnetic component 6 for the lead wire of the third coil 102 to extend out. After the lead wire of the third coil 102 passes through the third hole 62, it is electrically connected to the pin header connector 5.

[0042] For example, the third coil 102 is a metering coil that works based on the principle of electromagnetic induction. It can sense the alternating magnetic field generated by the change of the live wire current on the second busbar 8 and generate an induction signal corresponding to the real-time change of the live wire current. After the induction signal is sampled and processed by the subsequent circuit and algorithm, the charging current value and the charging amount can be obtained. In addition, the number of turns wound on the second magnetic core 101 is preferably 1000 turns.

[0043] In addition, the second magnetic core 101 is made of a soft magnetic material with high permeability and low remanence, and does not require pre-magnetization. The soft magnetic material with high permeability and low remanence refers to a soft magnetic material that has both high permeability and extremely low remanence. After the current is removed, the magnetic core can be demagnetized quickly without hysteresis accumulation error, ensuring metrological linearity and low current detection sensitivity over a wide current range. Typical materials include oriented silicon steel sheets, microcrystalline alloys, and low remanence ferrites.

[0044] The advantage of this setup is that the metering magnetic circuit and the leakage current detection magnetic circuit are independent and physically isolated from each other, and do not generate electromagnetic interference, ensuring the accuracy and stability of the two types of detection functions; the multi-turn metering coil improves the sensing sensitivity under low current, and the metering accuracy is better over a wide range; the low remanent magnetic core avoids hysteresis deviation after current impact, and the metering accuracy is not affected by long-term use.

[0045] Please refer to Figure 4The first magnetic component 4 is ring-shaped, the first busbar 7 is U-shaped, the first end of the first busbar 7 is the neutral wire input port, the second end of the first busbar 7 is the neutral wire output port connected to external equipment, the second end of the first busbar 7 extends along its length outside the first magnetic component 4, and the end face of the second end of the first busbar 7 is flush with the end face of the first end of the first busbar 7.

[0046] For example, the U-shaped structure of the first busbar 7 is formed by bending a whole piece of copper material, with the bottom bend being a rounded transition, and the bending radius matching the outer diameter of the first magnetic component 4; the two straight sides of the U-shape are parallel to each other, the first straight side extends vertically upward through the first space 41 in the middle of the first magnetic component 4, and the second straight side extends parallel upward along the outer side wall of the first magnetic component 4, with the top end faces of the two straight sides on the same horizontal plane.

[0047] The advantages of this design are that the neutral current can pass through the detection magnetic core completely in a single pass through the first busbar 7, which meets the magnetic circuit requirements for residual current detection; the flush design at both ends puts the input and output ports on the same mating plane, which is convenient for unified assembly with external wiring terminals; the outward extension layout does not occupy the passage space in the middle of the magnetic core, and the overall structure is more compact.

[0048] The second magnetic component 6 is ring-shaped, and the first magnetic component 4 and the second magnetic component 6 are coaxially arranged. The second busbar 8 is U-shaped. The first end of the second busbar 8 is a live wire input port, and the second end of the second busbar 8 is a live wire output port connected to an external device. The second end of the second busbar 8 extends along its length outside the second magnetic component 6, and the end face of the second end of the second busbar 8 is flush with the end face of the first end of the second busbar 8.

[0049] For example, the first busbar 7 and the second busbar 8 are both independent integrated copper busbars. The conductor substrate is high-conductivity copper, and the surface is treated with a double layer of protection and insulation: the substrate surface is first plated with nickel 2-4 micrometers thick as a base layer, and then plated with tin 3-5 micrometers to form a conductive protective layer, which improves the anti-oxidation ability and wiring reliability; an insulating protective layer is formed outside the protective layer by electrophoretic coating or heat shrink tubing, so as to realize the electrical isolation between the busbar and the magnetic components, the housing and adjacent components, and avoid the risk of short circuit or creepage.

[0050] The advantages of this setup are that the independent integrated copper busbar has strong current carrying capacity, low internal resistance, and low heat generation; the surface integrated insulation treatment eliminates the need for additional assembly of insulation bushings, improving assembly efficiency; the coaxial layered arrangement of the two busbars ensures uniform and consistent magnetic circuit coupling, guaranteeing the accuracy and stability of detection and measurement.

[0051] The bottom of the first housing 1 has a first groove 16 for accommodating the bent portion at the bottom of the first busbar 7. The first groove 16 is strip-shaped. The first groove 16 has a fourth hole 11 and a fifth hole 12 for the first end and the second end of the first busbar 7 to pass through, respectively. The bottom of the first housing 1 also has a sixth hole 13 and a seventh hole 14 for the first end and the second end of the second busbar 8 to pass through, respectively.

[0052] For example, the bent portion refers to the curved transition section at the bottom of the structure of the first busbar 7 and the second busbar 8, which is used to connect the two vertical straight edge segments; the groove depth of the first groove 16 is greater than the axial thickness of the bent portion of the first busbar 7, and the groove width is adapted to the lateral dimension of the bent portion. After the first busbar 7 is assembled, its bent portion is completely contained inside the first groove 16 and does not protrude from the bottom surface of the first housing 1, ensuring that the mating surface of the first housing 1 and the second housing 2 is flat and without protrusions when they are stacked and assembled.

[0053] The bottom of the second housing 2 has a second groove 27 for accommodating the bent portion at the bottom of the second busbar 8. The second groove 27 is strip-shaped and has an eighth hole 21 and a ninth hole 22 for the first and second ends of the second busbar 8 to pass through, respectively.

[0054] For example, the first end face of the first busbar 7, the second end face of the first busbar 7, the first end face of the second busbar 8, and the second end face of the second busbar 8 are all flush with each other and at the same horizontal height, so that all input and output ports are on the same mating plane, which facilitates the unified assembly of external wiring.

[0055] The sixth hole 13 and the eighth hole 21 are aligned along the length of the first housing 1 and the second housing 2, and the seventh hole 14 and the ninth hole 22 are aligned along the length of the first housing 1 and the second housing 2.

[0056] For example, the fourth hole 11, the fifth hole 12, the sixth hole 13, the seventh hole 14, the eighth hole 21, and the ninth hole 22 are all circular through holes; the centers of the sixth hole 13 and the eighth hole 21 are completely coincident along the stacked axial direction, and the opening diameters are the same; the centers of the seventh hole 14 and the ninth hole 22 are completely coincident along the stacked axial direction, and the opening diameters are the same; the hole walls of the corresponding holes are continuous without misalignment steps, ensuring that the two straight sides of the second busbar 8 can vertically and smoothly penetrate the two shell layers without any jamming resistance.

[0057] The first housing 1 has a first seat 15 for the first magnetic component 4 to be fitted inside. The position of the first seat 15 corresponds to the fourth hole 11 and the sixth hole 13, and both the fourth hole 11 and the sixth hole 13 are through holes that pass through the first seat 15. The side of the circuit board 3 closest to the first housing 1 abuts against the first seat 15, and the circuit board 3 has a strip-shaped through hole 31 at the position corresponding to the fourth hole 11 and the sixth hole 13 for the two to pass through. The length of the strip-shaped through hole 31 covers the center distance between the fourth hole 11 and the sixth hole 13, and the width is adapted to the cross-sectional size of the straight side of the busbar. It can simultaneously accommodate the first end of the first busbar 7 and the first end of the second busbar 8 to pass vertically through, eliminating the need to make two separate round holes on the circuit board 3, reducing the hole alignment accuracy requirements and improving assembly convenience.

[0058] For example, the assembly and potting are performed in the following order: First, the first magnetic component 4 is fitted onto the first seat 15 inside the first housing 1 to complete the welding and fixing of the coil lead of the detection component 9 to the circuit board 3; simultaneously, the second magnetic component 6 is fitted onto the fourth seat 25 inside the second housing 2 to complete the wiring of the third coil 102 lead of the metering component 10 to the pin connector 5; then, potting compound is injected into the first housing 1 and the second housing 2 respectively and allowed to cure, so that each internal component is encapsulated and fixed as a whole. In addition, the strip-shaped through hole 31 of the circuit board 3 can be inserted and mated with the part of the first seat 15 exposed by the potting compound; after the potting compound in the first housing 1 and the second housing 2 has cured, the first housing 1 and the second housing 2 are stacked and aligned and assembled, and finally the first busbar 7 and the second busbar 8 are inserted respectively.

[0059] The advantage of this setup is that the independent potting of the dual-shell system can achieve complete physical isolation between the detection module and the measurement module, effectively blocking electromagnetic interference and heat conduction between the modules, and improving the accuracy and long-term stability of the two types of detection functions. The first base 15 provides positioning support for the first magnetic component 4 and the circuit board 3. During the potting process, the internal components will not be displaced or shifted, ensuring the accuracy of the magnetic circuit position and the coaxiality of the through hole, and improving the consistency of batch assembly.

[0060] The inner wall of the second housing 2 is provided with a second seat 23, and a third groove 24 is opened in the second seat 23 along the length direction of the second housing 2. The first end of the pin header connector 5 is provided with a third seat 51 that is inserted into the third groove 24. The first housing 1 is also provided with a through hole for the pin header connector 5 to pass through, and the second end of the pin header connector 5 extends out of the first housing 1 through the through hole. For example, the third seat 51 is integrally molded from insulating rigid engineering plastic. During assembly, the third seat is inserted into the third slot to achieve axial positioning of the pin header connector 5 and prevent it from moving into the first housing 1. The two leads of the third coil 102 are respectively welded to the two pin ends inside the pin header connector 5. The pin header connector 5 outputs a metering signal. After the external metering circuit collects the signal, it calculates the real-time charging current and the cumulative charging capacity.

[0061] The advantage of this design is that the pin header connector 5 integrates an axial positioning structure and signal conversion function, eliminating the need for additional long leads to connect to external circuits. This simplifies the assembly process and ensures high connection reliability. The insulating third connector 51 guarantees electrical insulation between the pin and the housing, avoiding signal interference and short circuit risks, and ensuring the stability of the metering output signal.

[0062] The second housing 2 is provided with a fourth seat 25 for the second magnetic component 6 to be fitted. The position of the fourth seat 25 corresponds to the position of the eighth hole 21, and the eighth hole 21 is a through hole that passes through the fourth seat 25. The end face of the fourth seat near the first housing 1 abuts against the second housing 2. The sixth hole 13 and the eighth hole 21 are combined to form a through hole through which the first end of the second busbar 8 passes.

[0063] For example, after the fourth housing 25 is fitted and fixed to the second magnetic component 6, its top end face is flush with the top end face of the second housing 2; when the first housing 1 and the second housing 2 are stacked and assembled, the bottom surface of the first housing 1 and the top surface of the second housing 2 are tightly fitted, and the sixth hole 13 and the eighth hole 21 are connected vertically to form a continuous and complete through hole. The hole wall has no misalignment steps, so there will be no problem of glue accumulating and blocking the hole during the potting process, and there will be no jamming resistance when inserting the second busbar 8.

[0064] The working principle of this current sensor is as follows: When the charging circuit is working, current flows into the sensor from the first end of the second busbar 8 (live wire input port) and the first end of the first busbar 7 (neutral wire input port). The live wire current carried by the second busbar 8 passes through the second magnetic core 101 and the first magnetic core 91 in sequence; the neutral wire current carried by the first busbar 7 passes through the first magnetic core 91. Subsequently, the neutral wire current flows out directly through the second end of the first busbar 7 (neutral wire output port) without passing through the second magnetic core 101; the live wire current flows out through the second end of the second busbar 8 (live wire output port), passing completely through the second magnetic core 101 to form a metering magnetic circuit.

[0065] Under normal, leakage-free operating conditions, the live wire current of the second busbar 8 is equal in magnitude and opposite in direction to the neutral wire current of the first busbar 7. The vector sum of the magnetic fields generated by the two in the first magnetic core 91 is zero, the first magnetic core 91 is in a zero magnetic flux state, the feedback coil has no effective induction signal output, and the circuit board 3 does not trigger the protection action.

[0066] The self-test function of the link works as follows: the self-test drive circuit on the circuit board 3 supplies a low-frequency excitation current of constant amplitude to the self-test coil at a set period. After the preset excitation current is supplied to the self-test coil, a differential-mode magnetic field corresponding to the residual current fault is generated inside the first magnetic core, so that the detection component feels a magnetic flux change similar to the actual leakage current state, thereby realizing the functional verification of the detection link; the circuit board 3 collects the induced signal corresponding to the simulated magnetic field through the feedback coil, compares it with the expected output result, and judges whether the function of the entire leakage current detection link is intact and whether the output is stable, thereby realizing online stability verification without disassembling the machine for testing.

[0067] Second Embodiment Unlike the first embodiment, in this embodiment, the number of the first hole 42, the second hole 43, and the third hole 62 are all set to two, corresponding to the input and output leads of each coil, respectively.

[0068] For example, the input and output leads of the first coil 92 are independently passed through two first holes 42, the input and output leads of the second coil 93 are independently passed through two second holes 43, and the input and output leads of the third coil 102 are independently passed through two third holes 62. The two holes of the same coil are arranged circumferentially at intervals along the corresponding magnetic components, and the leads are parallel to each other and do not cross or overlap after passing through.

[0069] The advantage of this setup is that each lead wire is run independently, avoiding the risk of mutual compression and wear on the insulation layer when multiple leads share a single hole, resulting in higher electrical insulation reliability; the neat and orderly routing of the leads facilitates subsequent welding operations, improving assembly efficiency and product consistency.

[0070] Third Embodiment Unlike the first embodiment, in this embodiment, circuit board 3 is a printed circuit board 3 integrating signal processing circuitry. It has four interface pins: Pin1, Pin2, Pin3, and Pin4. Pin1 is the positive power supply pin, used to connect to an external DC power supply to power the signal conditioning and processing circuitry on circuit board 3, and is electrically connected to the signal output circuit of detection component 9. Pin2 is the trigger signal output pin, used to output a leakage protection trigger signal, connected to the signal output terminal of circuit board 3, and outputs an action command when the residual current exceeds the limit. Pin3 is the ground pin, providing a common reference ground for the power supply circuit and the signal circuit, improving signal stability. Pin4 is the zero-point bias detection pin, which can identify changes in the input voltage level. When the external voltage decreases, it triggers the zero-point bias detection process, completes the magnetic flux zero-point correction, and then feeds back the calibration status.

[0071] The advantage of this setup is that it integrates power supply, trigger output, grounding, and zero-point calibration functions into a single pin group, with clear and unified interface definitions. External wiring does not require additional scattered leads, facilitating quick connection between the sensor and the external main control circuit. At the same time, all pins are concentrated on one side of the circuit board 3, which is compatible with the single-sided wiring layout of the stacked housing.

[0072] The two pins extending out of the first housing 1 from the outside of the pin header connector 5 constitute the external signal output interfaces Pin5 and Pin6.

[0073] When a leakage fault occurs in the circuit, some current is discharged through grounding or other non-main circuit paths, causing the vector sum of the live wire current of the second busbar 8 and the neutral wire current of the first busbar 7 to be non-zero. This current difference is the residual current, which refers to the vector sum of the currents of all energized conductors in the distribution circuit, also known as the leakage current. The residual current will generate an independent induced magnetic field in the first magnetic core 91, forming a differential-mode signal, which is a differential induced signal generated by the residual current and distinguished from the common-mode current magnetic field of normal operation. The feedback coil generates a reverse compensation magnetic field based on the principle of magnetic balance. The corresponding compensation current signal is transmitted to the circuit board 3 for processing and outputting a TRIP trigger signal. The above-mentioned TRIP trigger signal is the leakage protection action signal, which is output from the Pin2 pin in the form of a level transition or a switching pulse. It is used to drive an external relay or trip unit to disconnect the main power supply circuit and realize the leakage protection function.

[0074] At the same time, the live wire current passing through the second busbar 8 in the second magnetic core 101 generates an alternating magnetic field. The metering coil outputs an induced voltage signal that is proportional to the instantaneous value of the live wire current based on the principle of electromagnetic induction. This signal is output to the outside through pins 5 and 6 for external metering circuits to collect. After calculation and integration, the real-time charging current value and the cumulative charging capacity are obtained.

[0075] The zero-point bias calibration works as follows: the external control circuit pulls down the input voltage of pin 4 and sends a zero-point calibration command to the sensor; after receiving the command, the circuit board 3 starts the zero-point bias detection process, and detects the zero-point magnetic flux offset of the first magnetic core 91 under the condition of no primary side current input; after detecting the bias amount, the circuit board 3 passes a fine-tuning compensation current of the corresponding direction and amplitude to the feedback coil to generate a reverse magnetic field to cancel the bias magnetic flux, so that the first magnetic core 91 returns to the zero magnetic flux reference point, and the zero-point calibration is completed; after calibration, the circuit board 3 can feed back the calibration completion status to the outside through the signal loop to ensure the consistency of the detection accuracy of the sensor during long-term use.

[0076] Fourth embodiment Unlike the first embodiment, in this embodiment, the outer shell used by the first magnetic component 4 and the second magnetic component 6 to cover the first magnetic core 91 and the second magnetic core 101 is made of soft magnetic material to enhance the ability to resist electromagnetic interference.

[0077] For example, the aforementioned soft magnetic material for electromagnetic shielding refers to a soft magnetic functional material possessing high initial permeability, low coercivity, and easy magnetization and demagnetization characteristics. When used as the shell of a magnetic component, it can form a magnetic shielding path due to its low magnetoresistance, guiding external stray interference magnetic fields to be conducted and bypassed along the shell wall, preventing them from penetrating to the working area of ​​the internal magnetic core. Simultaneously, it can also block the internal working magnetic field from radiating outwards, avoiding electromagnetic interference to surrounding electronic devices. Typical soft magnetic materials for shielding include permalloy, electrical pure iron, oriented silicon steel sheets, and high-permeability manganese-zinc ferrite, which can be selected according to the sensor's operating frequency band and shielding effectiveness requirements.

[0078] Fifth Embodiment Unlike the first embodiment, in this embodiment, a fifth seat 26 is provided on the side of the fourth seat 25. The fifth seat 26 is columnar and is combined with the fourth seat 25 to form a positioning and insertion point for the second magnetic component 6.

[0079] In summary, this application has at least the following advantages: First, it has strong anti-interference ability: by physically separating the first magnetic component 4 and the second magnetic component 6 and installing them in independent cavities, and using soft magnetic material shielding, the electromagnetic interference and heat generated by the metering circuit current are effectively isolated, which significantly improves the accuracy and stability of leakage current detection.

[0080] Secondly, it has high metering accuracy: the second magnetic core 101 uses a soft magnetic material with high permeability and low remanence and is not magnetized. It is in an extremely low remanence state, has strong anti-saturation ability, and can maintain linear output within the dynamic current range, thus achieving high-precision current metering.

[0081] Third, it has a high degree of modularity: the split structure allows the first magnetic component 4 and the second magnetic component 6 to be produced, tested, and potted independently. If any module fails, it can be replaced individually, which greatly reduces manufacturing and maintenance costs.

[0082] Fourth, the layout is reasonable and compact: the U-shaped long and short busbar layout makes full use of the internal space of the first magnetic component 4 and the second magnetic component 6, and only the current is measured for the live wire, which simplifies the structure and meets the functional requirements at the same time.

[0083] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A current sensor, characterized in that, include: The circuit board (3), the first housing (1) and the second housing (2) are stacked together, the first housing (1) contains a first magnetic component (4), and the second housing (2) contains a second magnetic component (6). The first magnetic component (4) is provided with a detection component (9) inside. A first space (41) is formed in the middle of the first magnetic component (4) for the first busbar (7) to pass through. The first end of the first busbar (7) passes through the first space (41) of the first magnetic component (4) from bottom to top and is electrically connected to the circuit board (3). The second magnetic component (6) is provided with a metering component (10). A second space (61) is formed in the middle of the second magnetic component (6) for the second busbar (8) to pass through. The first space (41) and the second space (61) are aligned along the length direction. The first end of the second busbar (8) passes through the second space (61) and the first space (41) from bottom to top and is electrically connected to the circuit board (3).

2. A current sensor according to claim 1, characterized in that, The detection component (9) includes a first magnetic core (91), which is located inside the first magnetic component (4) and surrounds the first space (41) in a circumferential manner. A first coil (92) and a second coil (93) are wound around the first magnetic core (91). A first hole (42) is opened on the first magnetic component (4) for the lead wire of the first coil (92) to extend out. A second hole (43) is opened on the first magnetic component (4) for the lead wire of the second coil (93) to extend out. The lead wires of the first coil (92) and the second coil (93) pass through the first hole (42) and the second hole (43) respectively and are electrically connected to the circuit board (3).

3. A current sensor according to claim 1, characterized in that, The metering component (10) includes a second magnetic core (101), which is located inside the second magnetic component (6) and is arranged circumferentially around the second space (61). A third coil (102) for outputting current metering signals is wound around the second magnetic core (101). A third hole (62) is opened on the second magnetic component (6) for the lead wire of the third coil (102) to extend out. After the lead wire of the third coil (102) passes through the third hole (62), it is electrically connected to the pin header connector (5).

4. A current sensor according to claim 2, characterized in that, The first magnetic component (4) is ring-shaped, the first busbar (7) is U-shaped, the first end of the first busbar (7) is a neutral input port, the second end of the first busbar (7) is a neutral output port connected to an external device, the second end of the first busbar (7) extends along its length direction outside the first magnetic component (4), and the end face of the second end of the first busbar (7) is flush with the end face of the first end of the first busbar (7).

5. A current sensor according to claim 4, characterized in that, The second magnetic component (6) is ring-shaped, and the first magnetic component (4) and the second magnetic component (6) are coaxially arranged. The second busbar (8) is U-shaped. The first end of the second busbar (8) is a live wire input port, and the second end of the second busbar (8) is a live wire output port connected to an external device. The second end of the second busbar (8) extends along its length outside the second magnetic component (6), and the end face of the second end of the second busbar (8) is flush with the end face of the first end of the second busbar (8).

6. A current sensor according to claim 5, characterized in that, The bottom of the first housing (1) has a first groove (16) for accommodating the bent portion at the bottom of the first busbar (7). The first groove (16) is strip-shaped. The first groove (16) has a fourth hole (11) and a fifth hole (12) for the first end and the second end of the first busbar (7) to pass through, respectively. The bottom of the first housing (1) also has a sixth hole (13) and a seventh hole (14) for the first end and the second end of the second busbar (8) to pass through, respectively. And / or, the bottom of the second housing (2) has a second groove (27) for accommodating the bent portion at the bottom of the second busbar (8). The second groove (27) is strip-shaped. The second groove (27) has an eighth hole (21) and a ninth hole (22) for the first end and the second end of the second busbar (8) to pass through, respectively.

7. A current sensor according to claim 6, characterized in that, The sixth hole (13) and the eighth hole (21) are aligned along the length of the first housing (1) and the second housing (2), and the seventh hole (14) and the ninth hole (22) are aligned along the length of the first housing (1) and the second housing (2).

8. A current sensor according to claim 6 or 7, characterized in that, The first housing (1) is provided with a first seat (15) for the first magnetic component (4) to be fitted. The position of the first seat (15) corresponds to the fourth hole (11) and the sixth hole (13). The fourth hole (11) and the sixth hole (13) are both through holes that pass through the first seat (15). The side of the circuit board (3) close to the first housing (1) abuts against the first seat (15). The circuit board (3) has a strip-shaped through hole (31) at the position corresponding to the fourth hole (11) and the sixth hole (13) for the two to pass through.

9. A current sensor according to claim 3, characterized in that, The second housing (2) has a second seat (23) on its inner wall. The second seat (23) has a third groove (24) arranged along the length of the second housing (2). The first end of the pin header connector (5) has a third seat (51) that is inserted into the third groove (24). The first housing (1) also has a through hole for the pin header connector (5) to pass through. The second end of the pin header connector (5) extends out of the first housing (1) through the through hole.

10. A current sensor according to claim 6, characterized in that, The second housing (2) is provided with a fourth seat (25) for the second magnetic component (6) to be fitted. The position of the fourth seat (25) corresponds to the position of the eighth hole (21), and the eighth hole (21) is a through hole that passes through the fourth seat (25). The end face of the fourth seat (25) near the first housing (1) abuts against the second housing (2). The sixth hole (13) and the eighth hole (21) are combined to form a through hole through which the first end of the second busbar (8) passes.

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