Rogowski coil

Abstract

The utility model provides a Rogowski coil, which belongs to the field of high-frequency current measurement and comprises a Rogowski coil body and a plurality of PCBs (printed circuit boards), the PCBs are overlapped along the thickness direction of the PCBs, at least part of the PCBs which are continuously overlapped are used for winding the Rogowski coil body, and the axial direction of the Rogowski coil body is the same as the thickness direction of the PCBs. A current-carrying conductor is arranged on at least one of the PCBs where the Rogowski coil body is wound, the current-carrying conductor comprises a first interface, a second interface and a measuring line, the first interface and the second interface are connected with a tested circuit, the measuring line is connected with the first interface and the second interface, and the measuring line is arranged in the axial direction of the Rogowski coil body. Along the axial direction of the Rogowski coil body, the projection of the measuring line is located in the projection of the coil of the Rogowski coil body. Alternating current in a measured circuit flows through the current-carrying conductor to generate a magnetic field, induced electromotive force is generated in the Rogowski coil body, the current in the measured circuit is measured, and the current measurement precision is high.

Description

Technical Field

[0001] This utility model belongs to the field of high-frequency current measurement, and in particular relates to a Rogowski coil. Background Technology

[0002] Rogowski coils are frequently used in alternating current applications. A Rogowski coil is a toroidal coil uniformly wound on a non-ferromagnetic material. Its output signal is the differential of the current with respect to time. By passing this output voltage signal through a circuit that integrates the voltage, the input current can be accurately reproduced, thus precisely reproducing the waveform of the measured current signal. PCB Rogowski coils, or printed circuit board Rogowski coils, are coils designed with computer software assistance. Their conductors are uniformly printed on the coil, resulting in optimized structural parameters and system stability compared to ordinary Rogowski coils. PCB Rogowski coils serve as current sensing units for measurement.

[0003] However, both types of Rogowski coils are prone to the following two errors when measuring alternating current: (1) eccentric position error (the current-carrying conductor is perpendicular to the coil cross-section, but not located at the coil axis); (2) tilt position error (the current-carrying conductor and the coil cross-section are not perpendicular, but have a certain angle). When the Rogowski coil measures alternating current in a high-voltage circuit, the above two errors have little impact on the measurement results. However, when the Rogowski coil measures alternating current in a low-voltage circuit, the above two errors will affect the accuracy of the current measurement, thus reducing the adaptability of the Rogowski coil to different situations. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a Rogowski coil to solve the problem that the Rogowski coil is difficult to accurately measure alternating current in low-voltage circuits in the prior art.

[0005] To achieve the above and other related objectives, this utility model provides a Rogowski coil, comprising:

[0006] Rogowski coil body;

[0007] Multiple PCBs are arranged in an overlapping manner along the thickness direction of the PCBs. At least some of the PCBs are continuously overlapping for winding the Rogowski coil body. The axial direction of the Rogowski coil body is in the same direction as the thickness direction of the PCBs. At least one of the PCBs winding the Rogowski coil body has a current-carrying conductor. The current-carrying conductor includes a test lead and a first interface and a second interface for connecting to the circuit under test. The test lead is arranged around the axial direction of the Rogowski coil body. Along the axial direction of the Rogowski coil body, the projection of the test lead is located within the projection of the coil of the Rogowski coil body.

[0008] Optionally, the PCB board assembly has a measuring hole along the axial direction of the Rogowski coil body.

[0009] Optionally, the direction of the measuring hole coincides with the axial extension line of the Rogowski coil body.

[0010] Optionally, the number of PCBs with current-carrying conductors is at least 2, and the projection trajectories of the test lines on each PCB overlap along the axial direction of the Rogowski coil body.

[0011] Optionally, the PCB board used for winding the Rogowski coil body is provided with a plurality of first winding holes and second winding holes corresponding to the first winding holes. The plurality of first winding holes are arranged at intervals around the axial direction of the Rogowski coil body, and the plurality of second winding holes are arranged at intervals around the axial direction of the Rogowski coil body. The first winding holes and the second winding holes are arranged correspondingly in the circumferential direction of the Rogowski coil body. The first winding holes are closer to the axial direction of the Rogowski coil body than the second winding holes. The wires of the Rogowski coil body pass through the first winding holes and the second winding holes of each of the PCB boards in sequence to form the Rogowski coil body.

[0012] Optionally, the test line is a circle with a notch, and the two ends of the circular notch of the test line are a first interface and a second interface, respectively. The center of the circular test line is located on the extension line of the axial direction of the Rogowski coil body.

[0013] Optionally, along the radial direction of the measuring line, the measuring line is at the same distance from the first winding hole and the second winding hole, respectively.

[0014] Optionally, the distance between the center of the first winding hole and the center of the corresponding second winding hole is in the range of 2 to 200 mm.

[0015] Optionally, the Rogowski coil further includes a shielding layer, and multiple PCBs are sandwiched between two shielding layers along the thickness direction of the PCBs.

[0016] Optionally, the shielding layer has connection points respectively corresponding to the first interface and the second interface, and the first interface and the second interface are electrically connected to the corresponding connection points respectively.

[0017] As described above, the Rogowski coil of this invention has the following beneficial effects:

[0018] By placing a current-carrying conductor on the PCB board, the circuit under test (DUT) can be connected to the conductor through a first interface and a second interface. The alternating current flowing through the conductor generates a magnetic field, which in turn induces an electromotive force within the Rogowski coil, allowing the measurement of the alternating current. Placing the current-carrying conductor on the PCB board improves the accuracy of current measurement, avoiding situations where inaccurate current measurements are caused by deviations in the placement of the wires within the Rogowski coil. Attached Figure Description

[0019] Figure 1 This is a plan view of the shielding layer of the first layer of the Rogowski coil in an embodiment of the present invention.

[0020] Figure 2 This is a planar schematic diagram of the second layer of the Rogowski coil according to an embodiment of the present invention.

[0021] Figure 3 This is a plan view of the third layer of the Rogowski coil in an embodiment of the present invention.

[0022] Figure 4 This is a plan view of the fourth layer of the Rogowski coil in an embodiment of the present invention.

[0023] Figure 5 This is a plan view of the fifth layer of the Rogowski coil in an embodiment of the present invention.

[0024] Figure 6 This is a plan view of the shielding layer of the sixth layer of the Rogowski coil in an embodiment of this utility model.

[0025] Figure 7 This is a schematic diagram illustrating the principle of Rogowski coil measuring current through a current-carrying conductor, according to an embodiment of this utility model.

[0026] Labeling Explanation: 1. Measuring Hole; 2. Connection Position; 3. Second Winding Hole; 4. First Winding Hole; 5. Current Carrying Conductor; 501. First Interface; 502. Second Interface; 503. Guide Wire; 504. Measuring Wire; 6. Rogowski Coil Body. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0028] Please see Figures 1 to 6It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the disclosed technical content. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0029] To provide a detailed description of this utility model, the following is a specific description of a Rogowski coil according to this utility model:

[0030] Please combine Figures 1 to 6 As shown, this utility model provides a PCB Rogowski coil, including a Rogowski coil body 6 and multiple PCB boards. The multiple PCB boards are arranged in an overlapping manner along the thickness direction of the PCB boards. At least some of the PCB boards are continuously overlapping for winding the Rogowski coil body 6. The axial direction of the Rogowski coil body 6 is in the same direction as the thickness direction of the PCB boards. At least one of the PCB boards on which the Rogowski coil body 6 is wound has a current-carrying conductor 5. The current-carrying conductor 5 includes a test line and a first interface 501 and a second interface 502 for connecting to the circuit under test. The first interface 501 is electrically connected to the second interface 502 through the test line 504. The test line 504 is arranged around the axial direction of the Rogowski coil body 6. Along the axial direction of the Rogowski coil body 6, the projection of the test line 504 is located within the projection of the coil of the Rogowski coil body 6. By placing a current-carrying conductor 5 on at least a portion of the PCB board, the circuit under test can be connected to the current-carrying conductor 5 through a first interface 501 and a second interface 502. The alternating current in the circuit under test generates a magnetic field after flowing through the current-carrying conductor 5, which induces an electromotive force within the Rogowski coil body 6, thereby allowing the measurement of the magnitude of the alternating current in the circuit under test. Placing the current-carrying conductor 5 on the PCB board improves the accuracy of current measurement and avoids situations where inaccurate current measurement results can occur due to deviations in the placement of the wires in the Rogowski coil.

[0031] Figure 7 This is a schematic diagram illustrating the principle of a Rogowski coil measuring current through a current-carrying conductor, according to an embodiment of this utility model. Figure 7 As shown, the circuit under test forms a closed loop with the current-carrying conductor 5 through the first interface 501 and the second interface 502. Figure 7The trajectory of the current-carrying conductor 5 is simplified to a straight line. The Rogowski coil body 6 is arranged around the current-carrying conductor. The alternating current in the circuit under test will pass through the current-carrying conductor 5 and form a changing magnetic field around the current-carrying conductor 5. The Rogowski coil body 6 in the magnetic field can generate an induced electromotive force. The induced electromotive force is proportional to the derivative of the current in the circuit under test. The ratio is the proportionality coefficient. The proportionality coefficient is related to the number of coil turns, the cross-section of the frame, the magnetic permeability, etc. After integrating the electromotive force, the current in the circuit under test can be restored.

[0032] The PCB board assembly has a measuring hole 1 along the axial direction of the Rogowski coil body 6. While ensuring its original function of measuring alternating current, the Rogowski coil can also more accurately measure the magnitude of the alternating current in the circuit through the measuring wire 504. When measuring the alternating current in a high-voltage circuit, the wires in the circuit under test can be passed through the Rogowski coil to obtain the alternating current value. When measuring the alternating current in a low-voltage circuit, a more accurate alternating current value can be obtained through the current-carrying conductor 5. In this embodiment, the direction of the measuring hole 1 coincides with the axial extension line of the Rogowski coil body 6. This ensures that the distance between the hole wall of the measuring hole 1 and the Rogowski coil body 6 is equal, thus ensuring the accuracy of the measured alternating current magnitude in the circuit under test.

[0033] The number of PCBs with current-carrying conductors 5 is at least two, and the projected trajectories of the test lines 504 on each PCB overlap along the axial direction of the Rogowski coil body 6. It is understood that the number of PCBs is generally set to an even number during the PCB setup process. To increase the current density passing through the current-carrying conductors 5, current-carrying conductors 5 are placed on at least two PCBs. By increasing the number of PCBs with current-carrying conductors 5, the heat generated when the test current flows through the test guide can be reduced.

[0034] like Figures 2 to 5As shown, the PCB board used for winding the Rogowski coil body 6 has multiple first winding holes 4 and corresponding second winding holes 3. The multiple first winding holes 4 are arranged at intervals along the axial direction of the Rogowski coil body 6, and the multiple second winding holes 3 are also arranged at intervals along the axial direction of the Rogowski coil body 6. The first winding holes 4 and second winding holes 3 are correspondingly arranged circumferentially around the Rogowski coil body 6. The first winding holes 4 are closer to the axial direction of the Rogowski coil body 6 than the second winding holes 3. The wires of the Rogowski coil body 6 pass through the first winding holes 4 and second winding holes 3 of each PCB board in sequence to form the Rogowski coil body 6. It is understood that the wires here are insulated wires. By opening the first winding hole 4 and the second winding hole 3 on the PCB to wind the Rogowski coil body 6, the specific structural form of the Rogowski coil body 6 can be designed in the design software before production and assembly. This can ensure the accuracy of the hollow coil structure with complex structural form. At the structural design level, it can ensure that the coil cross-sectional area is uniform, the coil turns are regularly and discretely distributed, and the coil plane is perpendicular to the PCB board, thereby improving the accuracy of current measurement and the ability to resist electromagnetic interference.

[0035] Specifically, the measuring wire 504 is a circle with a notch. The two ends of the circular notch of the measuring wire 504 are the first interface 501 and the second interface 502, respectively. The center of the circular measuring wire 504 is located on the axial extension line of the Rogowski coil body 6. The measuring wire 504 is equidistant from each of the first winding holes 4, and also equidistant from each of the second winding holes 3. The shape of the measuring wire 504 is aesthetically pleasing and neat, and this design improves measurement accuracy. The measuring wire 504 can also be square or other irregular shapes. The shape of the measuring wire 504 can be adjusted according to actual needs.

[0036] Specifically, along the radial direction of the circular measuring line 504, the measuring line 504 is equidistant from both the first winding hole 4 and the second winding hole 3. This further improves the accuracy of current measurement.

[0037] In this embodiment, limited by the current factory's processing technology and safety regulations, the distance between the center of the first winding hole 4 and the center of the corresponding second winding hole 3 ranges from 2 to 200 mm. The distance between the centers of the first winding hole 4 and the second winding hole 3 can be three times the line width, and the optimal distance between the centers of the two winding holes is 2.54 to 10 mm.

[0038] like Figure 1 and Figure 6As shown, the Rogowski coil also includes a shielding layer, which is arranged along the thickness direction of the PCB board on the outermost layer of multiple PCB boards. The shielding layer improves electromagnetic interference resistance, balances temperature rise, reduces temperature drift, and also prevents external electromagnetic interference when measuring the current in the circuit under test through the current-carrying conductor 5, further increasing the accuracy of current measurement.

[0039] Specifically, the shielding layer has connection positions 2 respectively corresponding to the first interface 501 and the second interface 502, and the first interface 501 and the second interface 502 are electrically connected to the corresponding connection positions 2 respectively.

[0040] In this embodiment, a guide line 503 is also provided between the test line 504 and the first interface 501 and the second interface 502. The guide line 503 extends toward the edge of the corresponding PCB board, one end of the guide line 503 is connected to the test line 504, and the other end of the guide line 503 passes through the Rogowski coil body 6. By providing the guide line 503, it is convenient for the connection position 2 to be electrically connected to the first interface 501 and the second interface 502 respectively, and the space layout on the PCB can be reasonably arranged.

[0041] In this embodiment, along the stacking direction of the PCB boards, a shielding layer, four PCB boards with Rogowski coil bodies 6 wound around them, and a shielding layer are stacked sequentially. Current-carrying conductors 5 are disposed on the middle two of the four PCB boards with Rogowski coil bodies 6. In some embodiments, along the stacking direction of the PCB boards, a shielding layer, three PCB boards with Rogowski coil bodies 6 wound around them, a PCB board with current-carrying conductors 5, and a shielding layer are stacked sequentially. Current-carrying conductors 5 are disposed on the middle one of the three PCB boards with Rogowski coil bodies 6. The above two PCB board solutions each have their advantages and disadvantages in terms of performance. Only the preferred solution considering both performance and manufacturability is listed here. Based on this solution, modifications to the stacking layers (e.g., removing the shielding layer) and shape (e.g., changing the circular current-carrying conductor 5 to other shapes) are possible, but the essential principle remains the same and is also protected by this utility model.

[0042] In summary, by placing a current-carrying conductor 5 on the PCB board, the circuit under test can be connected to the current-carrying conductor 5 through the first interface 501 and the second interface 502. The alternating current in the circuit under test generates a magnetic field after flowing through the current-carrying conductor 5, which in turn induces an electromotive force within the Rogowski coil body 6, thereby allowing the measurement of the magnitude of the alternating current in the circuit under test. Placing the current-carrying conductor 5 on the PCB board improves the accuracy of current measurement and avoids situations where inaccurate current measurement results can occur due to deviations in the placement of the wires in the Rogowski coil.

[0043] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A Roebel coil, characterized in that, include: Rogowski coil body; Multiple PCBs are arranged in an overlapping manner along the thickness direction of the PCBs. At least some of the PCBs are continuously overlapping for winding the Rogowski coil body. The axial direction of the Rogowski coil body is in the same direction as the thickness direction of the PCBs. At least one of the PCBs winding the Rogowski coil body has a current-carrying conductor. The current-carrying conductor includes a test lead and a first interface and a second interface for connecting to the circuit under test. The first interface is electrically connected to the second interface through the test lead. The test lead is arranged around the axial direction of the Rogowski coil body. Along the axial direction of the Rogowski coil body, the projection of the test lead is located within the projection of the coil of the Rogowski coil body.

2. The Roebel coil according to claim 1, characterized in that: The PCB board assembly has a measuring hole along the axial direction of the Rogowski coil body.

3. The Roebel coil according to claim 2, characterized in that: The direction of the measuring hole coincides with the axial extension line of the Rogowski coil body.

4. The Roebel coil of claim 1, characterized in that: The number of PCBs with current-carrying conductors is at least 2, and the projected trajectories of the test lines on each PCB overlap along the axial direction of the Rogowski coil body.

5. The Roebel coil of claim 1, characterized in that: The PCB board used for winding the Rogowski coil body has multiple first winding holes and corresponding second winding holes. The multiple first winding holes are arranged at intervals around the axial direction of the Rogowski coil body, and the multiple second winding holes are arranged at intervals around the axial direction of the Rogowski coil body. The first winding holes and the second winding holes are arranged correspondingly in the circumferential direction of the Rogowski coil body. The first winding holes are closer to the axial direction of the Rogowski coil body than the second winding holes. The wires of the Rogowski coil body pass through the first winding holes and the second winding holes of each of the PCB boards in sequence to form the Rogowski coil body.

6. The Roebel coil according to claim 5, characterized in that: The test line is a circle with a notch. The two ends of the circular notch of the test line are the first interface and the second interface, respectively. The center of the circular test line is located on the extension line of the axial direction of the Rogowski coil body.

7. The Roebel coil according to claim 6, characterized in that: Along the radial direction of the circular measuring line, the measuring line is at the same distance from the first winding hole and the second winding hole, respectively.

8. The Roebel coil according to claim 5, characterized in that: The distance between the center of the first winding hole and the center of the corresponding second winding hole ranges from 2 to 200 mm.

9. The Roebel coil according to any one of claims 1 to 8, characterized in that: The Rogowski coil also includes a shielding layer, and multiple PCBs are sandwiched between two shielding layers along the thickness direction of the PCBs.

10. The Roebel coil according to claim 9, characterized in that: The shielding layer has connection points respectively corresponding to the first interface and the second interface, and the first interface and the second interface are electrically connected to the corresponding connection points respectively.

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