Anti-perpendicular magnetic field interference inductor, electric power meter thereof, and manufacturing method thereof

Abstract

This invention relates to an anti-vertical magnetic field interference sensor, its power meter, and its manufacturing method. It includes a ring-shaped Rogowski coil and a ring-shaped vertical magnetic field cancellation coil. The Rogowski coil comprises several self-adhesive hollow coils connected in series. Each hollow coil has a hollow cavity inside. The wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil are identical. Adjacent hollow coils have opposite winding directions. There are an even number of hollow coils, symmetrically distributed around a circle on the same horizontal plane. The cavities together form a ring-shaped channel. The vertical magnetic field cancellation coil is located at the center of the ring-shaped channel. The area enclosed by the vertical magnetic field cancellation coil is equal to the area enclosed by the Rogowski coil. The Rogowski coil and the ring-shaped vertical magnetic field cancellation coil are used to surround the outside of a primary current line and have a pair of output terminals for detecting the primary current line signal. This effectively solves the problem of easy interference from external power frequency electromagnetic fields during low-current detection.

Description

Technical Field

[0001] This invention relates to an anti-vertical magnetic field interference sensor for use in electrical instruments, its power meter and manufacturing method thereof, and particularly to an anti-vertical magnetic field interference sensor, its power meter and manufacturing method thereof applicable to the field of power transmission. Background Technology

[0002] In the development of smart grids in China, electronic instrument transformers are a key component of primary equipment. Currently, current transformers are the primary method used for AC current detection.

[0003] There are two main types of current transformers. One type is the iron core coil transformer, which is made in different sizes according to the rated current. Its disadvantages are that it is large in size and high in cost. It is used in iron cores and has magnetic saturation phenomenon and nonlinearity. Therefore, its current measurement range is narrow and it is commonly used for 0.1In to 2In (rated current).

[0004] Another type is the Rogowski coil current sensor. Also known as an air-core transformer or magnetic potential gauge, the Rogowski coil is widely used for measuring large currents. A Rogowski coil is a coil uniformly wound around a non-magnetic frame, surrounding a conductor, and is used to measure the current flowing through the conductor. A Rogowski coil current sensor consists of two main parts: the Rogowski coil sensing head and the subsequent signal integration and processing circuitry. The sensing head is the signal sensing element of the measuring element; it establishes a coupling relationship with the measured current by capturing the electromagnetic field in space. Rogowski coils are characterized by their small size and low material cost, excellent linearity, and wide measurement range, suitable for currents from 0.1 In to tens of thousands of A or even higher. However, they are particularly susceptible to electromagnetic interference, especially power frequency electromagnetic fields. They are typically used for detecting large currents, such as AC currents of several hundred amperes or more. When used for small currents, they are highly susceptible to interference from external power frequency electromagnetic fields. This causes the sampling current output by the Rogowski coil to include not only the measuring current flowing in the measured conductor but also interference signal current generated by the surrounding electromagnetic field. When the measuring current is small, the interference signal current may even cover the measuring current, leading to a large measurement error and failing to accurately reflect the actual current, thus creating certain limitations.

[0005] Therefore, in the power sector, especially under the stringent requirements related to the safety of electricity use for the general public, how to optimize instrument transformers to improve their ability to resist external magnetic field interference is an urgent problem that needs to be studied and solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a better vertical magnetic field interference sensor, its power meter, and its manufacturing method that can resist or eliminate external vertical magnetic field interference in all directions.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical approach:

[0008] An anti-vertical magnetic field interference sensor includes a ring-shaped Rogowski coil and a ring-shaped vertical magnetic field cancellation coil located inside and connected in series with the Rogowski coil. The Rogowski coil includes several self-adhesive hollow coils connected in series. Each hollow coil has a hollow cavity inside. The wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil are consistent. Adjacent hollow coils have opposite winding directions. The outermost end of a single hollow coil is connected to the outermost end of an adjacent hollow coil, and the innermost end of a single hollow coil is connected to the innermost end of an adjacent hollow coil. There are an even number of hollow coils, which are symmetrically distributed around a circle on the same horizontal plane. The cavities together form a ring channel. The vertical magnetic field cancellation coil is located at the center of the ring channel. The area enclosed by the vertical magnetic field cancellation coil is equal to the area enclosed by the Rogowski coil. The Rogowski coil and the ring-shaped vertical magnetic field cancellation coil are used to surround the outside of a primary current line and have a pair of output terminals for detecting the primary current line signal.

[0009] As a further improvement of the present invention, an FPC plate bent into a ring shape is provided in the annular channel, and the vertical magnetic field cancelling coil is provided on the FPC plate and located at the center of the annular channel.

[0010] As a further improvement of the present invention, a single hollow coil includes a single coil layer continuously wound on a coil fixture, arranged neatly according to the wire diameter. After each single coil layer is wound, the next single coil layer is wound in the opposite direction on the outside. The adjacent inner and outer single coil layers are arranged neatly with each other. The number of single coil layers is odd and ≥3 layers. The spacing between each adjacent hollow coil is less than 1-5% of the radius of the Rogowski coil.

[0011] As a further improvement of the present invention, the output terminal includes a first output terminal and a second output terminal. One end of the Rogowski coil is electrically connected to the first output terminal. The Rogowski coil is used to wrap around the primary current line in the forward direction. The other end of the Rogowski coil is electrically connected to the annular vertical magnetic field cancelling coil on the FPC board. The annular vertical magnetic field cancelling coil is used to wrap around the primary current line in the reverse direction. The other end of the annular vertical magnetic field cancelling coil is electrically connected to the second output terminal. The Rogowski coil and the annular vertical magnetic field cancelling coil are connected in series and reversed to form a closed loop.

[0012] As a further improvement of the present invention, the FPC board is formed by bending a strip of flexible PCB board into a ring shape, and the ring vertical magnetic field cancelling coil is located on the surface of the FPC board or inside the FPC board. The two ends of the FPC board are provided with solder terminals on the surface for electrically connecting the Rogowski coil and / or the output terminal.

[0013] As a further improvement of the present invention, the output terminal includes a first output terminal and a second output terminal. The Rogowski coil includes an arc-shaped first Rogowski coil and an arc-shaped second Rogowski coil that can together form a complete circular ring. Both the first Rogowski coil and the second Rogowski coil include a connecting end and an opening end located at both ends. The connecting ends of the first Rogowski coil and the second Rogowski coil are close to each other and are respectively connected to the first output terminal and the second output terminal. The first output terminal and the second output terminal are twisted together to form the output terminal. The opening ends of the first Rogowski coil and the second Rogowski coil are close to each other and are respectively used to electrically connect to the two ends of the vertical magnetic field cancelling coil on the FPC board.

[0014] As a further improvement of the present invention, the connection ends of the first Rogowski coil and the connection ends of the second Rogowski coil are crossed and electrically connected to the first output end and the second output end respectively.

[0015] As a further improvement of the present invention, the anti-vertical magnetic field interference sensor further includes a housing for accommodating the Rogowski coil. The housing includes an annular bottom wall, an inner wall extending laterally from the inner circle of the bottom wall, and an outer wall extending laterally from the outer circle of the bottom wall. The bottom wall, inner wall, and outer wall form an annular receiving cavity. The Rogowski coil is accommodated in each of the receiving cavities. The inner wall passes through the center of the Rogowski coil to form a primary current passage hole for the primary current line to pass through the center of the Rogowski coil and the vertical magnetic field cancellation coil. The receiving cavity is provided with a coil positioning cavity for fixing each hollow coil. A partition is provided between adjacent coil positioning cavities. An FPC board positioning groove is provided on the partition for holding and positioning the FPC board.

[0016] To achieve the above-mentioned technical objectives, the present invention may also employ the following technical methods: An electrical meter includes a housing of the electrical meter and the aforementioned anti-vertical magnetic field interference sensor located within the housing of the electrical meter.

[0017] To achieve the above-mentioned technical objectives, the present invention may also employ the following technical methods: A method for manufacturing a vertical magnetic field interference resistant sensor, comprising: Multiple hollow coils are continuously wound from enameled wire. Each hollow coil includes a single coil layer that is continuously wound on a coil fixture and arranged neatly according to the wire diameter. After each single coil layer is wound, the next single coil layer is wound in the opposite direction on one side. The adjacent inner and outer single coil layers are arranged neatly. The number of single coil layers is odd and ≥3 layers. The adjacent hollow coils are wound in opposite directions, the outermost end of a single hollow coil is connected to the outermost end of an adjacent hollow coil, and the innermost end of a single hollow coil is connected to the innermost end of an adjacent hollow coil. A strip-shaped FPC board is set and bent into a ring. A vertical magnetic field cancellation coil is provided on the bent FPC board, and the FPC board is inserted into the Rogowski coil. The hollow coil and the vertical magnetic field cancelling coil are arranged together in a ring, so that multiple hollow coils are symmetrically distributed on the same horizontal plane with the circle as the center. The holes together form a ring channel, and the vertical magnetic field cancelling coil is located at the center of the ring channel, so that the reclamation area enclosed by the vertical magnetic field cancelling coil is equal to the reclamation area enclosed by the Rogowski coil. The Rogowski coil and the toroidal vertical magnetic field cancelling coil are used to surround the outside of the primary current line, and a pair of output terminals are provided for detecting the primary current line signal. The output terminals extend further outward to output signals.

[0018] Compared to existing technologies, the vertical magnetic field interference sensor of this invention features a hollow coil with identical wire diameter, number of turns, number of layers, inner diameter, and outer diameter for each coil, but adjacent hollow coils have opposite winding directions. An even number of hollow coils are arranged symmetrically around a circle on the same horizontal plane, with the holes forming a ring-shaped channel. The vertical magnetic field cancellation coil is located at the center of this ring-shaped channel, and its enclosed area is equal to the enclosed area of ​​the Rogowski coil. This arrangement, employing an "alternating positive and negative direction" connection method, integrates multiple discrete coils into a high-performance Rogowski coil, effectively utilizing spatial symmetry to cancel common-mode interference while ensuring sensitive response to the measured signal, thereby further improving the anti-interference capability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the anti-vertical magnetic field interference induction Rogowski coil according to the first embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the anti-vertical magnetic field interference sensor FPC board and output terminal according to the first embodiment of the present invention; Figure 3 This is a schematic diagram of the combination of the Rogowski coil, FPC board and output terminal of the anti-vertical magnetic field interference sensor according to the first embodiment of the present invention. Figure 4 This is a schematic diagram of the Rogowski coil and output terminal of the anti-vertical magnetic field interference sensor according to the second embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the anti-vertical magnetic field interference sensor FPC board according to the second embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the Rogowski coil, FPC board and output terminal of the anti-vertical magnetic field interference sensor according to the second embodiment of the present invention. Figure 7 yes Figure 6A structural diagram from another angle; Figure 8 This is a schematic diagram of the structure of the anti-vertical magnetic field interference sensor housing according to the second embodiment of the present invention; Figure 9 This is a schematic diagram of the anti-vertical magnetic field interference sensor of the second embodiment of the present invention before packaging; Figure 10 This is a partial exploded cross-sectional view of the anti-vertical magnetic field interference sensor of the second embodiment of the present invention before packaging.

[0020] Figure label: Anti-vertical magnetic field interference sensor 100, 200; hollow coil 10; single coil layer 1001; hole 1002; outermost end 1003; innermost end 1004; first single coil layer 10011; second single coil layer 10012; third single coil layer 10013; first hollow coil 101; second hollow coil 102; third hollow coil 103; coil start end 111; coil end end 112; first output end 1101; second output end 1102; first Rogowski coil 11; connection end 11 03; Opening / closing end 1104; Second Rogowski coil 12; Connecting end 1203; Opening / closing end 1204; First output end 1101'; Second output end 1102'; Annular channel 104; FPC board 2; Vertical magnetic field cancellation coil 21; Welding ends 2113, 2113'; Welding ends 2213, 2213'; Housing 61; Bottom wall 611; Inner wall 612; Outer wall 613; Receiving cavity 616; Coil positioning cavity 618; Partition 619; FPC board positioning groove 6191; Primary current passage hole 630 Detailed Implementation Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0021] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0022] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0023] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0025] Please refer to Figures 1 to 3The diagram shown is a schematic representation of the anti-vertical magnetic field interference sensor 100 according to the first embodiment of the present invention. An anti-vertical magnetic field interference sensor 100 includes a ring-shaped Rogowski coil and a ring-shaped vertical magnetic field cancellation coil 21 located inside the Rogowski coil and connected in series with it. The Rogowski coil includes a plurality of self-adhesive hollow coils 10 connected in series. Each hollow coil 10 has a hollow hole 1002 inside. The wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil 10 are consistent. Adjacent hollow coils 10 are wound in opposite directions. The outermost end 1003 of a single hollow coil 10 is adjacent to the outermost end 1003 of an adjacent hollow coil 10, and the innermost end 1004 of a single hollow coil 10 is adjacent to the innermost end 1004 of an adjacent hollow coil 10. Taking the implementation as an example, the first hollow coil 101 includes a first single coil layer 10011 continuously wound from left to right. Then, a second single coil layer 10012 is wound from right to left outside the first single coil layer 10011. Next, a third single coil layer 10013 is wound from left to right outside the second single coil layer 10012, and so on, until the outermost single coil layer 1001. Since the outermost single coil layer 1001 of the first hollow coil 101 is wound from left to right, the end of the outermost single coil layer 1001 of the first hollow coil 101 is located on the rightmost side. To the right of the first hollow coil 101 is the second hollow coil 102, which winds the first single coil layer 1001 from right to left. 0011, then the second single coil layer 10012 is wound from left to right outside the first single coil layer 10011, and then the third single coil layer 10013 is wound from right to left outside the second single coil layer 10012, and so on, until the outermost single coil layer 1001. The outermost single coil layer 1001 of the second hollow coil 102 is wound from right to left, so the end of the outermost single coil layer 1001 of the second hollow coil 102 is located on the leftmost side, and the end of the innermost single coil layer 1001 of the second hollow coil 102 is located on the rightmost side; wherein the end of the outermost single coil layer 1001 of the first hollow coil 101 is immediately connected to the outermost single coil layer 1001 of the second hollow coil 102. The end of the third hollow coil 103 is located to the right of the second hollow coil 102. The third hollow coil 103 is continuously wound from left to right to form the first single coil layer 10011. Then, the second single coil layer 10012 is wound from right to left outside the first single coil layer 10011. Then, the third single coil layer 10013 is wound from left to right outside the second single coil layer 10012. This process is repeated until the outermost single coil layer 1001. The outermost single coil layer 1001 of the third hollow coil 103 is wound from left to right, so the end of the outermost single coil layer 1001 of the third hollow coil 103 is located on the rightmost side, and the end of the innermost single coil layer 1001 of the third hollow coil 103 is located on the leftmost side.The end of the innermost single coil layer 1001 of the second hollow coil 102 is adjacent to the end of the innermost single coil layer 1001 of the third hollow coil 103; and a fourth hollow coil 10 is then arranged in the same configuration. There are an even number of hollow coils 10, which are symmetrically distributed around a circle on the same horizontal plane. The holes 1002 together form an annular channel 104. An FPC plate bent into an annular shape is provided in the annular channel 104. The vertical magnetic field cancellation coil 21 is provided on the FPC plate and located at the center of the annular channel 104. The area enclosed by the vertical magnetic field cancellation coil 21 is equal to the area enclosed by the Rogowski coil. The Rogowski coil and the annular vertical magnetic field cancellation coil 21 are used to surround the outside of the primary current line (not shown) and are provided with a pair of output terminals for detecting the primary current line signal. Thus, the aforementioned anti-vertical magnetic field interference sensor 100 possesses no magnetic saturation, making it extremely suitable for measuring very large currents, currents containing DC components (such as short-circuit fault currents, currents in power electronic equipment), and severely distorted currents; it has a wide frequency response, free from the limitations of eddy current losses, hysteresis losses, and distributed capacitance caused by the iron core, possessing a very wide bandwidth (from a few Hz to several MHz, or even higher), enabling it to accurately measure high-frequency currents, fast transient currents (such as lightning strikes, switching surges, and fast turn-off currents of power electronic switches), and currents containing rich harmonics; it has good linearity, with the output signal (induced voltage) strictly proportional to the rate of change (di / dt) of the measured current, and its response is linear when the coil design parameters (such as turns density and cross-sectional area) remain constant and there is no saturation. This design ensures a good linear relationship between input (current change rate) and output (voltage) throughout the entire measurement range, resulting in high measurement accuracy. It also features low load effect, with relatively low output impedance, minimizing the load effect on the measured circuit and minimally affecting the measured current loop, making it easy to integrate into the measurement system. Furthermore, it is flexible, lightweight, and easy to install, facilitating installation in space-constrained locations. The coil itself has good electrical isolation from the measured high-voltage conductor, improving operational safety. It offers a wide measurement range; by adjusting the number of coil turns and other component parameters, a single coil design can cover a very wide current measurement range (from a few amperes to millions of amperes) without requiring different turns ratios as in traditional CTs. It is also free of residual magnetism, leaving no residual magnetism after measurement and not affecting the accuracy of subsequent measurements, making it particularly suitable for measuring non-periodic transient large currents. Moreover, in this invention, adjacent hollow coils 10 are wound in opposite directions, causing their magnetic fields to tend to cancel each other out in space. Overall, it resembles a distributed, averaged "current loop" sensor rather than a long helical tube.Under a uniform vertical magnetic field, the interference voltages induced by adjacent hollow coils 10 are in opposite directions. If an even number of hollow coils 10 are perfectly symmetrical and uniformly distributed, these induced voltages can cancel each other out, making the total interference voltage close to zero. This provides a natural and strong suppression capability against uniform vertical magnetic fields, thus improving the anti-interference capability against uniform vertical power frequency magnetic fields. Adjacent hollow coils 10 are in opposite directions. When the primary current line is between two adjacent hollow coils 10, one is coupled positively and the other negatively, compensating for each other. This makes the overall output less sensitive to the radial positional deviation of the primary current line on the circumference, resulting in more stable measurements. Therefore, it is insensitive to the positional deviation of the primary current line. The magnetic fields of adjacent hollow coils 10 partially cancel each other out, resulting in a small total self-inductance. The potentials of adjacent hollow coils 10 are close, resulting in a smaller distributed capacitance, thus achieving a higher resonant frequency and a wider operating bandwidth. The errors of adjacent hollow coils 10 tend to cancel each other out, making the consistency requirements for a single hollow coil 10 relatively relaxed, and improving robustness. In summary, this invention utilizes an even number of hollow coils 10 to form a Rogowski coil. To achieve high precision and strong anti-interference capability (especially against power frequency magnetic fields), it employs a "staggered" connection method, integrating multiple discrete coils into a single high-performance Rogowski coil. This effectively utilizes spatial symmetry to cancel common-mode interference while ensuring a sensitive response to the measured signal, thereby further improving its resistance to external interference.

[0026] Specifically, each hollow coil 10 comprises continuously wound single coil layers 1001 arranged neatly according to wire diameter on a coil fixture. After each single coil layer 1001 is wound, the next single coil layer 1001 is wound in the opposite direction on the outside. Adjacent inner and outer single coil layers 1001 are neatly arranged. The number of single coil layers 1001 is odd and ≥3. This arrangement ensures that the wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each individual hollow coil 10 are consistent, guaranteeing the electromagnetic interference cancellation effect between them and facilitating the winding and manufacturing of Rogowski coils.

[0027] The spacing between each adjacent hollow coil 10 is less than 1-5% of the radius of the Rogowski coil. Since the gap between adjacent coils is a weak point for external magnetic field interference, especially in mass production where gaps cannot be completely eliminated, the magnetic field will preferentially penetrate through the gap, disrupting the symmetrical cancellation condition. For example, when the gap width reaches 5% of the coil diameter, the interference suppression ratio may drop by more than 20 dB. Furthermore, the gap causes unequal effective cross-sectional areas of adjacent coils (higher magnetic flux density on the gap side), making the induced electromotive force generated by the magnetic field no longer strictly equal and unable to completely cancel each other out. This design of the present invention avoids magnetic leakage between adjacent hollow coils 10, providing the detection accuracy and stability of the entire anti-vertical magnetic field interference sensor 100.

[0028] In the first embodiment, the output terminal includes a first output terminal 1101 and a second output terminal 1102. One end of the Rogowski coil is electrically connected to the first output terminal 1101. The Rogowski coil is used to wrap around the outside of the primary current line in the forward direction. The other end of the Rogowski coil is electrically connected to the annular vertical magnetic field cancelling coil 21 on the FPC board 2. The annular vertical magnetic field cancelling coil is used to wrap around the outside of the primary current line in the reverse direction. The other end of the annular vertical magnetic field cancelling coil 21 is electrically connected to the second output terminal 1102. Thus, the Rogowski coil and the annular vertical magnetic field cancelling coil 21 are connected in series and reversed to form a closed loop. In a specific embodiment, the Rogowski coil has a coil start end 111 and a coil end 112. The FPC board 2 can be provided with solder ends 2113 and 2213 at both ends of the annular vertical magnetic field cancelling coil 21. The two solder ends 2113 and 2213 are respectively soldered to one end of the Rogowski coil and the second output end 1102. With this configuration, the Rogowski coil start end 111 is connected to the first output end 1101. After the Rogowski coil wraps around the current line once, the coil end 112 is connected to the solder end 2113 of the annular vertical magnetic field cancelling coil 21 on the FPC board 2. The annular vertical magnetic field cancelling coil 21 then wraps around the current line again in the opposite direction, and its solder end 2213 is electrically connected to the second output end 1102. Furthermore, the Rogowski coil start end 111 and the second output end 1102 intersect to prevent magnetic leakage. The anti-vertical magnetic field interference sensor 100 of the present invention can effectively utilize the series reverse connection of the Rogowski coil and the ring vertical magnetic field cancellation coil 21 to achieve mutual cancellation of the induced electromotive force of the interfering magnetic field. When subjected to magnetic field interference perpendicular to the plane where the Rogowski coil is distributed, the vertical magnetic field cancellation coil 21 located at the center of the Rogowski coil can better cancel the induced electromotive force generated by the Rogowski coil itself. Thus, the Rogowski coil and the vertical magnetic field cancellation coil 21 enable the anti-vertical magnetic field interference sensor 100 of the present invention to perfectly cancel external magnetic field interference from all directions as a whole. This solves the technical problem that the current ordinary Rogowski coil (not shown) is easily affected by external power frequency electromagnetic field interference when used for small current detection, resulting in large measurement errors and failing to reflect the actual current normally. This breaks through the current limitations of Rogowski coil applications.

[0029] The FPC board 2 is formed by bending a strip of flexible PCB board into a ring shape. The annular vertical magnetic field cancellation coil 21 is located on the surface of the FPC board 2 or inside the FPC board 2. The FPC board 2 has solder terminals 2113 and 2213 on its surface for electrically connecting the Rogowski coil and / or the output terminal. This configuration ensures that the annular vertical magnetic field cancellation coil 21 is in a predetermined plane, that is, at the exact center of the Rogowski coil annular channel 104, which greatly facilitates the manufacturing and installation positioning of the annular vertical magnetic field cancellation coil 21 itself.

[0030] Please refer to Figures 4 to 10 The diagram shown is a schematic representation of the anti-vertical magnetic field interference sensor 200 according to the second embodiment of the present invention. The Rogowski coil includes an arc-shaped first Rogowski coil 11 and an arc-shaped second Rogowski coil 12 that together form a complete circular ring. Both the first Rogowski coil 11 and the second Rogowski coil 12 include connecting ends 1103 and 1203 and opening / closing ends 1104 and 1204 located at both ends. The connecting ends 1103 of the first Rogowski coil 11 and 1203 of the second Rogowski coil 12 are close to each other and are respectively connected to a first output end 1101' and a second output end 1102'. The first output end 1101' and the second output end 1102' are twisted together to form the output ends. The opening / closing ends 1104 of the first Rogowski coil 11 and 1204 of the second Rogowski coil 12 are close to each other and are respectively used to electrically connect to the two ends of the vertical magnetic field cancellation coil 21 on the FPC board 2. Specifically, the vertical magnetic field cancelling coil 21 has welding ends 2113' and 2213' at both ends. The opening and closing ends 1104 of the first Rogowski coil 11 and 1204 of the second Rogowski coil 12 are welded to the welding ends 2113' and 2213' respectively. With this configuration, the Rogowski coil can be opened at the two opening and closing ends 1104 and 1204 to allow the primary current line to enter or disconnect. The FPC board 2 can also allow the primary current line to enter or disconnect at this location, so that the Rogowski coil and the vertical magnetic field cancelling coil 21 can be opened and closed at the same time, which facilitates installation and subsequent maintenance and replacement.

[0031] The connection terminals 1103 of the first Rogowski coil 11 and 1203 of the second Rogowski coil 12 are crossed and electrically connected to the first output terminal 1101' and the second output terminal 1102', respectively. This configuration avoids gaps when the Rogowski coils are connected to the first output terminal 1101' and the second output terminal 1102', thus preventing magnetic leakage at these points.

[0032] Taking the second embodiment as an example, the anti-vertical magnetic field interference sensor 100, 200 of the present invention further includes a housing 61 for accommodating the Rogowski coil. The housing 61 includes an annular bottom wall 611, an inner wall 612 extending laterally from the inner circle of the bottom wall 611, and an outer wall 613 extending laterally from the outer circle of the bottom wall 611. The bottom wall 611, the inner wall 612, and the outer wall 613 form an annular receiving cavity 616. The Rogowski coil is accommodated in each of the receiving cavities 616. The inner wall 612 passes through the center of the Rogowski coil to form a primary current passage hole 630 for allowing the primary current line to pass through the center of the Rogowski coil and the vertical magnetic field cancellation coil 21. The receiving cavity 616 is provided with a coil positioning hole 618 for fixing each hollow coil 10. A partition 619 is provided between adjacent coil positioning holes 618. An FPC board positioning groove 6191 for holding and positioning the FPC board 2 is provided on the partition 619. The housing 61 can be made of PC with added glass fiber, PPS, or PEEK, etc., and the Rogowski coil is encapsulated in epoxy resin within the receiving cavity 616. This provides the housing 61 with better strength, stability, and corrosion resistance, increasing the overall lifespan of the anti-vertical magnetic field interference sensor 100. Furthermore, the coil positioning cavity 618 effectively secures each hollow coil 10, and the FPC board positioning slot 6191 stably holds and positions the FPC board 2, ensuring that the relative positions of the hollow coil 10 and the vertical magnetic field cancellation coil 21 remain unchanged, thus preventing any vibration-induced noise from affecting measurement accuracy.

[0033] This invention also protects an electrical meter, including a housing and vertical magnetic field interference sensors 100 and 200 located within the housing. The core component of the electrical meter lies in the resistance of the vertical magnetic field interference sensors 100 and 200 to external magnetic field interference. The ability of the vertical magnetic field interference sensors 100 and 200 to resist external magnetic field interference enables the electrical meter to have excellent power data detection accuracy, giving it a core competitive advantage in the market.

[0034] This invention also protects a method for manufacturing a vertical magnetic field interference sensor 100, which is used to manufacture the above-mentioned vertical magnetic field interference sensor 100, comprising: a plurality of hollow coils 10 continuously wound from enameled wire, each hollow coil 10 comprising a single coil layer 1001 continuously wound on a coil fixture and arranged in a straight line according to wire diameter, after each single coil layer 1001 is wound, the next single coil layer 1001 is wound in the opposite direction on one side, the adjacent inner and outer single coil layers 1001 are arranged in a straight line, and the number of the single coil layers 1001 is odd and ≥3 layers; The adjacent hollow coils 10 are wound in opposite directions. The outermost end 1003 of a single hollow coil 10 is connected to the outermost end 1003 of the adjacent hollow coil 10, and the innermost end 1004 of a single hollow coil 10 is connected to the innermost end 1004 of the adjacent hollow coil 10. A strip-shaped FPC board is set and bent into a ring. A vertical magnetic field cancellation coil 21 is provided on the bent FPC board, and the FPC board is inserted into the Rogowski coil. The hollow coil 10 and the vertical magnetic field cancelling coil 21 are arranged together in a ring, so that multiple hollow coils 10 are symmetrically distributed on the same horizontal plane with the circle as the center. The holes 1002 together form a ring channel 104. The vertical magnetic field cancelling coil 21 is located at the center of the ring channel 104, so that the reclamation area enclosed by the vertical magnetic field cancelling coil 21 is equal to the reclamation area enclosed by the Rogowski coil. The Rogowski coil and the annular vertical magnetic field cancellation coil 21 are used to surround the outside of the primary current line, and a pair of output terminals are provided for detecting the primary current line signal. The output terminals extend further outward to output signals. With this configuration, the manufacturing method of the anti-vertical magnetic field interference sensors 100 and 200 can better maintain the consistency of the structure and distribution of each hollow coil 10. It can effectively utilize geometric symmetry and the series reverse connection of the vertical magnetic field cancellation coil 21 to achieve mutual cancellation of the induced electromotive force of the interference magnetic field. When subjected to magnetic field interference perpendicular to the plane where the Rogowski coil is distributed, the vertical magnetic field cancellation coil 21 located at the center of the Rogowski coil can better cancel the induced electromotive force generated by the Rogowski coil itself. Thus, the Rogowski coil and the vertical magnetic field cancellation coil 21 enable the anti-vertical magnetic field interference sensors 100 and 200 of the present invention to perfectly cancel external magnetic field interference from all directions as a whole. This breaks through the current limitations of Rogowski coil applications and solves the technical problem that ordinary Rogowski coils (not shown) are easily interfered with by external power frequency electromagnetic fields when used for small current detection, resulting in large measurement errors and failing to reflect the actual current correctly.

[0035] Furthermore, in this invention, adjacent hollow coils 10 are wound in opposite directions, causing their magnetic fields to tend to cancel each other out in space. Overall, this resembles a distributed, averaged "current loop" sensor rather than a long solenoid. Under a uniform vertical magnetic field, the interference voltages induced by adjacent hollow coils 10 are in opposite directions. If an even number of hollow coils 10 are perfectly symmetrical and uniformly distributed, these induced voltages can cancel each other out, making the total interference voltage close to zero. This provides a natural and powerful suppression capability against uniform vertical magnetic fields, thus improving the anti-interference capability against uniform vertical power frequency magnetic fields. Conversely, when the primary current line is between two adjacent air-core coils 10, one is coupled positively and the other negatively, compensating for each other. This makes the overall output less sensitive to the radial positional deviation of the primary current line on the circumference, resulting in more stable measurement. Therefore, it is insensitive to the positional deviation of the primary current line. The magnetic fields of adjacent air-core coils 10 partially cancel each other out, resulting in a small total self-inductance. The potentials of adjacent air-core coils 10 are close, resulting in a small distributed capacitance, thus achieving a higher resonant frequency and a wider operating bandwidth. The errors of adjacent air-core coils 10 tend to cancel each other out, making the consistency requirements for individual air-core coils 10 relatively relaxed and improving robustness.

[0036] In summary, the Rogowski coil of this invention, composed of an even number of hollow coils, adopts a "staggered" connection method in order to achieve high precision and strong anti-interference capability (especially against power frequency magnetic fields). This integrates multiple discrete coils into a high-performance Rogowski coil, which can effectively utilize spatial symmetry to cancel common-mode interference, while ensuring sensitive response to the measured signal, thereby further improving the ability to resist external interference.

[0037] It is worth noting that in this invention, the order of the above steps is not limited and can be adjusted according to the actual situation, all of which are within the protection scope of this invention.

[0038] 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 invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] The directional terms used in the various technical features described in the above embodiments, such as front, back, left, right, up, and down, are used only for the convenience of describing and understanding the various technical features, and do not constitute a limitation on specific directions in the actual use of the technical solution.

[0040] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A sensor resistant to vertical magnetic field interference, characterized in that: The device includes a ring-shaped Rogowski coil and a ring-shaped vertical magnetic field cancelling coil located inside and connected in series with the Rogowski coil. The Rogowski coil comprises several self-adhesive hollow coils connected in series. Each hollow coil has a hollow cavity inside. The wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil are consistent. Adjacent hollow coils have opposite winding directions. The outermost end of a single hollow coil is connected to the outermost end of an adjacent hollow coil, and the innermost end of a single hollow coil is connected to the innermost end of an adjacent hollow coil. There are an even number of hollow coils, which are symmetrically distributed around a circle on the same horizontal plane. The cavities together form a ring channel. The vertical magnetic field cancelling coil is located at the center of the ring channel. The area enclosed by the vertical magnetic field cancelling coil is equal to the area enclosed by the Rogowski coil. The Rogowski coil and the ring-shaped vertical magnetic field cancelling coil are used to surround the outside of the primary current line and have a pair of output terminals for detecting the primary current line signal.

2. The anti-vertical magnetic field interference sensor according to claim 1, characterized in that: The annular channel contains an FPC plate bent into a ring shape, and the vertical magnetic field cancelling coil is disposed on the FPC plate and located at the center of the annular channel.

3. The anti-vertical magnetic field interference sensor according to claim 1, characterized in that: Each hollow coil comprises a single coil layer continuously wound on a coil fixture, arranged neatly according to wire diameter. After each single coil layer is wound, the next single coil layer is wound in the opposite direction on the outside. Adjacent inner and outer single coil layers are arranged neatly. The number of single coil layers is odd and ≥3 layers. The spacing between each adjacent hollow coil is less than 1-5% of the radius of the Rogowski coil.

4. The anti-vertical magnetic field interference sensor according to claim 2, characterized in that: The output terminal includes a first output terminal and a second output terminal. One end of the Rogowski coil is electrically connected to the first output terminal. The Rogowski coil is used to wrap around the primary current line in the forward direction. The other end of the Rogowski coil is electrically connected to the annular vertical magnetic field cancelling coil on the FPC board. The annular vertical magnetic field cancelling coil is used to wrap around the primary current line in the reverse direction. The other end of the annular vertical magnetic field cancelling coil is electrically connected to the second output terminal. The Rogowski coil and the annular vertical magnetic field cancelling coil are connected in series and reversed to form a closed loop.

5. The anti-vertical magnetic field interference sensor according to claim 2, characterized in that: The FPC board is formed by bending a strip of flexible PCB board into a ring shape. The ring-shaped vertical magnetic field cancelling coil is located on the surface of the FPC board or inside the FPC board. The two ends of the FPC board are provided with solder terminals on the surface for electrically connecting the Rogowski coil and / or the output terminal.

6. The anti-vertical magnetic field interference sensor according to claim 2, characterized in that: The output terminal includes a first output terminal and a second output terminal. The Rogowski coil includes an arc-shaped first Rogowski coil and an arc-shaped second Rogowski coil that can together form a complete circular ring. Both the first Rogowski coil and the second Rogowski coil include a connecting end and an opening end located at both ends. The connecting ends of the first Rogowski coil and the second Rogowski coil are close to each other and are respectively connected to the first output terminal and the second output terminal. The first output terminal and the second output terminal are twisted together to form the output terminal. The opening ends of the first Rogowski coil and the second Rogowski coil are close to each other and are respectively used to electrically connect to the two ends of the vertical magnetic field cancelling coil on the FPC board.

7. The anti-vertical magnetic field interference sensor according to claim 6, characterized in that: The connection terminals of the first Rogowski coil and the second Rogowski coil cross each other and are electrically connected to the first output terminal and the second output terminal, respectively.

8. The anti-vertical magnetic field interference sensor according to claim 2, characterized in that: The anti-vertical magnetic field interference sensor also includes a housing for housing the Rogowski coil. The housing includes an annular bottom wall, an inner wall extending laterally from the inner circle of the bottom wall, and an outer wall extending laterally from the outer circle of the bottom wall. The bottom wall, inner wall, and outer wall form an annular receiving cavity. The Rogowski coil is housed in each of the receiving cavities. The inner wall passes through the center of the Rogowski coil to form a primary current passage hole for the primary current line to pass through the center of the Rogowski coil and the vertical magnetic field cancellation coil. The receiving cavity is provided with a coil positioning cavity for fixing each hollow coil. A partition is provided between adjacent coil positioning cavities. The partition is provided with an FPC board positioning groove for holding and positioning the FPC board.

9. An electrical meter, characterized in that: It includes a power meter housing and a vertical magnetic field interference sensor according to any one of claims 1 to 8 located inside the power meter housing.

10. A method for manufacturing a vertical magnetic field interference resistant sensor, for manufacturing the vertical magnetic field interference resistant sensor according to any one of claims 1 to 8, comprising: Multiple hollow coils are continuously wound from enameled wire. Each hollow coil includes a single coil layer that is continuously wound on a coil fixture and arranged neatly according to the wire diameter. After each single coil layer is wound, the next single coil layer is wound in the opposite direction on one side. The adjacent inner and outer single coil layers are arranged neatly. The number of single coil layers is odd and ≥3 layers. The adjacent hollow coils are wound in opposite directions, the outermost end of a single hollow coil is connected to the outermost end of an adjacent hollow coil, and the innermost end of a single hollow coil is connected to the innermost end of an adjacent hollow coil. A strip-shaped FPC board is set and bent into a ring. A vertical magnetic field cancellation coil is provided on the bent FPC board, and the FPC board is inserted into the Rogowski coil. The hollow coil and the vertical magnetic field cancelling coil are arranged together in a ring, so that multiple hollow coils are symmetrically distributed on the same horizontal plane with the circle as the center. The holes together form a ring channel, and the vertical magnetic field cancelling coil is located at the center of the ring channel, so that the reclamation area enclosed by the vertical magnetic field cancelling coil is equal to the reclamation area enclosed by the Rogowski coil. The Rogowski coil and the toroidal vertical magnetic field cancelling coil are used to surround the outside of the primary current line, and a pair of output terminals are provided for detecting the primary current line signal. The output terminals extend further outward to output signals.

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