Current sampling device and equipment based on double-line circuit

Abstract

The embodiment of the utility model provides a current sampling device and equipment based on a double-line circuit. The current sampling device comprises a sampling circuit arranged between a high-voltage side and a low-voltage side of a line connected with the current sampling device; the sampling resistor is connected in series in the sampling circuit so as to form sampling current under the potential difference of the high-voltage side and the low-voltage side; the compensation circuit is arranged to be close to the sampling resistor and is suitable for providing compensation current when the sampling circuit flows through the sampling current so as to generate a compensation magnetic field, and the compensation magnetic field is used for at least partially counteracting an induced magnetic field of the sampling circuit; and the pair of voltage sampling interfaces are respectively arranged at the two ends of the sampling resistor and are suitable for acquiring voltage signals at the two ends of the sampling resistor. Therefore, the influence of the inductance of the sampling resistor on the precision of the sampled current can be reduced.

Description

Technical Field

[0001] The exemplary embodiments disclosed herein generally relate to the field of electrical equipment, and particularly to current sampling devices and apparatus based on two-wire circuits. Background Technology

[0002] In industrial control or power distribution, current sampling is typically performed using precision resistors. However, regardless of the package type, precision resistors inevitably contain leads or parasitic inductance. These lead inductances or parasitic inductances can affect the sampling accuracy of the precision resistor. Utility Model Content

[0003] In a first aspect of this disclosure, a current sampling device based on a two-wire circuit is provided. The current sampling device includes: a sampling circuit disposed between a high-voltage side and a low-voltage side of a line to which the current sampling device is connected; a sampling resistor connected in series in the sampling circuit to form a sampling current under the potential difference between the high-voltage side and the low-voltage side; a compensation circuit disposed close to the sampling resistor and adapted to provide a compensation current during the flow of the sampling current in the sampling circuit to generate a compensation magnetic field, the compensation magnetic field being used to at least partially cancel the induced magnetic field of the sampling circuit; and a pair of voltage sampling interfaces disposed across the sampling resistor and adapted to acquire voltage signals across the sampling resistor.

[0004] In some embodiments, the compensation circuit is parallel to the sampling circuit, and the compensation current of the compensation circuit is equal in magnitude and opposite in direction to the sampling current of the sampling circuit.

[0005] In some embodiments, the distance between the compensation circuit and the sampling circuit is less than or equal to a predetermined distance.

[0006] In some embodiments, the compensation circuit is connected in series with the sampling circuit.

[0007] In some embodiments, the current sampling device further includes a compensation resistor connected in series in the compensation circuit.

[0008] In some embodiments, the current sampling device further includes a detection module coupled to a pair of voltage sampling interfaces to determine the sampling current of the sampling circuit based on the voltage signals of the pair of voltage sampling interfaces.

[0009] According to the current sampling device provided in this disclosure, a compensation circuit is arranged on one side of the sampling circuit, and a compensation current flows through the compensation circuit while the sampling current is flowing through the sampling circuit. The compensation current changes in the same way as the sampling current, but in the opposite direction. In this way, the compensation magnetic field generated in the compensation circuit can at least partially cancel the induced magnetic field in the sampling circuit. Therefore, the influence of resistance and inductance on the accuracy of the sampled current can be reduced, and the accuracy of the sampled current can be improved.

[0010] In a second aspect of this disclosure, a current sampling device is provided. The current sampling device includes a circuit board and a current sampling apparatus according to the first aspect of this disclosure, at least partially disposed within the circuit board.

[0011] In some embodiments, the sampling circuit and the compensation circuit are arranged in series on the same layer of the circuit board.

[0012] In some embodiments, the circuit board is a multilayer circuit board, and the sampling circuit and the compensation circuit are respectively arranged in adjacent layers of the circuit board, and the sampling circuit and the compensation circuit are aligned in the stacking direction of the multilayer circuit board.

[0013] In some embodiments, one of the sampling circuit and the compensation circuit is arranged inside the circuit board, and the other is attached to the surface of the circuit board.

[0014] It should be understood that the content described in this content section is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0015] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0016] Figure 1 A circuit diagram of a current sampling device according to some embodiments of the present disclosure is shown;

[0017] Figure 2 A schematic circuit diagram of a current sampling device according to some embodiments of the present disclosure is shown;

[0018] Figure 3A A schematic diagram of a current sampling device according to some embodiments of the present disclosure is shown;

[0019] Figure 3B A schematic diagram of a current sampling device according to some other embodiments of the present disclosure is shown;

[0020] Figure 3C A cross-sectional view of a current sampling device according to some embodiments of the present disclosure is shown; and

[0021] Figure 3D A cross-sectional view of a current sampling device according to some other embodiments of the present disclosure is shown. Detailed Implementation

[0022] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0023] It should be noted that the headings of any section / subsection provided herein are not limiting. Various embodiments are described throughout this document, and embodiments of any type may be included under any section / subsection. Furthermore, embodiments described in any section / subsection may be combined in any way with any other embodiments described in the same section / subsection and / or different sections / subsections.

[0024] In the description of embodiments of this disclosure, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions may also be included below. The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0025] As briefly mentioned earlier, the traditional method of determining the sampling current of a circuit using a precision resistor involves connecting a precision resistor in series with the circuit under test and detecting the voltage signal across the resistor. The sampling current is then determined based on the detected voltage signal and the resistance value of the precision resistor. However, under conditions of high frequency, high current, or large current fluctuations (di / dt), the instantaneous voltage drop caused by the lead inductance or parasitic inductance of the precision resistor can severely affect the sampling accuracy.

[0026] To reduce the impact of the inductance of precision resistors on sampling accuracy, conventional processing methods include: 1) compensating for the sampled values ​​through software, and 2) compensating for the sampled voltage using the hysteresis characteristics of resistors and capacitors.

[0027] However, the above methods also have certain drawbacks. For example, method 1) requires high software processing time and compensation accuracy, and usually needs to anticipate the range of current fluctuations (di / dt) that may occur in the actual circuit, and can only perform compensation within a defined range of current fluctuations. For method 2), fixed RC parameters can only compensate for a certain range of parasitic inductance, thus requiring high consistency of parasitic inductance of precision resistors.

[0028] The current sampling device and apparatus based on a two-wire circuit provided in this disclosure solve, or at least partially solve, the aforementioned problems and other potential problems existing in conventional solutions. According to some embodiments of the current sampling device based on a two-wire circuit, a compensation circuit is arranged on one side of the sampling circuit, and a compensation current flows through the compensation circuit during the sampling current. The compensation current changes in the same manner as the sampling current, but in the opposite direction. In this way, the compensation magnetic field generated in the compensation circuit can at least partially cancel the induced magnetic field in the sampling circuit. Therefore, the influence of resistance and inductance on the accuracy of the sampled current can be reduced, improving the accuracy of the sampled current.

[0029] Figure 1 A circuit diagram of a current sampling device according to some embodiments of the present disclosure is shown. Figure 1 As shown, the current sampling device generally includes a sampling circuit 1, a sampling resistor 2 connected in series in the sampling circuit 1, a pair of voltage sampling interfaces 5 arranged across the sampling resistor 2, and a compensation circuit 3 arranged close to the sampling circuit 1.

[0030] The sampling circuit 1 is arranged between the high-voltage side and the low-voltage side of the line to which the current sampling device is connected, so that the potential difference formed by the high-voltage side and the low-voltage side forms a sampling current on the sampling resistor 2.

[0031] In some embodiments, the current sampling device further includes a detection module 6, which is coupled to a pair of voltage sampling interfaces 5. The detection module 6 acquires the voltage signal across the sampling resistor 2 through the pair of voltage sampling interfaces 5, and determines the sampling current in the sampling circuit 1 based at least on the voltage signal and the characteristic parameters of the sampling resistor 2 (e.g., the resistance value of the sampling resistor 2).

[0032] In some embodiments, the compensation circuit 3 and the sampling circuit 1 are arranged parallel to each other, and the sampling current in the sampling circuit 1 is equal in magnitude and opposite in direction to the compensation current in the compensation circuit 3. Thus, the induced magnetic field generated in the compensation circuit 3 can at least partially cancel the induced magnetic field in the sampling circuit 1. Consequently, the inductance generated by the sampling resistor 2 can be reduced by decreasing the residual magnetic flux at the sampling resistor 2.

[0033] In one embodiment, the distance between the compensation circuit 3 and the sampling circuit 1 is less than or equal to a predetermined distance, specifically, according to an empirical formula. (In the formula, L is the inductance at sampling resistor 2, in H; l is the length of sampling circuit 1 and / or compensation circuit 3; d is the wire diameter of sampling circuit 1 and / or compensation circuit 3; a is the center distance between sampling circuit 1 and compensation circuit 3.) It can be seen that the smaller the distance between compensation circuit 3 and sampling circuit 1, the better the compensation circuit 3 cancels the induced magnetic field of sampling circuit 1. Therefore, in some embodiments, when conditions permit, compensation circuit 3 and sampling circuit 1 can be placed as close as possible so that compensation circuit 3 can better cancel the induced magnetic field of sampling circuit 1 at sampling resistor 2.

[0034] In some embodiments, the compensation circuit 3 and the sensing circuit can be connected in series. This ensures that the current in the compensation circuit 3 is equal to the current in the sensing circuit, and that they fluctuate synchronously. Therefore, the current sampling device can better handle high-frequency, high-current conditions and large current fluctuations (di / dt).

[0035] Figure 2 A schematic circuit diagram of a current sampling device according to some embodiments of the present disclosure is shown. Figure 2 As shown, in some embodiments, the current sampling device further includes a compensation resistor 4 connected in series in the compensation circuit 3, which is adapted to generate an inductance opposite to that of the sampling resistor 2 during the current change of the sampling circuit 1 (i.e., during the current change of the compensation circuit 3), thereby further improving the accuracy of the sampling current detection.

[0036] Figure 3A A schematic diagram of a current sampling device according to some embodiments of the present disclosure is shown. For example... Figure 3A As shown, the current sampling device includes a circuit board 7 and a current sampling device at least partially disposed within the circuit board 7. In some embodiments, the sampling circuit 1 and / or the compensation circuit 3 may be disposed within the circuit board 7 as a printed circuit layer, and the sampling circuit 1 and the compensation circuit 3 may be arranged parallel to each other and spaced apart by a predetermined interval. In some embodiments, the sampling circuit 1 and the compensation circuit 3 are connected in series and disposed on the same layer of the circuit board 7.

[0037] Figure 3B A schematic diagram of a current sampling device according to some other embodiments of the present disclosure is shown. For example... Figure 3B As shown, the traces in the circuit board can be appropriately bent (e.g., the traces in the circuit board have U-shaped bends) so that one part of the trace serves as the sampling circuit 1 and the other part serves as the compensation circuit 3. In this way, the space utilization of the circuit board 7 can be optimized, and the space occupied by the traces within the circuit board 7 can be reduced.

[0038] Figure 3C A cross-sectional view of a current sampling device according to some embodiments of the present disclosure is shown. Figure 3C As shown, in some embodiments, the circuit board 7 of the current sampling device can be a multilayer circuit board, with the sampling circuit 1 and the compensation circuit 3 arranged in different printed circuit layers of the multilayer circuit board, and the sampling circuit 1 and the compensation circuit 3 arranged in parallel along the stacking direction of the multilayer circuit board.

[0039] Figure 3D A cross-sectional view of a current sampling device according to some other embodiments of the present disclosure is shown, such as Figure 3D As shown, the sampling circuit 1 of the current sampling device can be arranged within the circuit board 7, and the compensation circuit 3 can be attached to the surface of the circuit board 7 and kept parallel to the sampling circuit 1. Therefore, the sampling circuit 1 in the existing circuit board 7 can be optimized by using an external circuit to improve the sampling accuracy of the sampling circuit 1 in the circuit board 7. In some embodiments, the compensation circuit 3 of the current sampling device can be arranged within the circuit board 7, and the sampling circuit 1 is arranged attached to the circuit board 7.

[0040] Various implementations of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed implementations. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described implementations. The terminology used herein is chosen to best explain the principles, practical applications, or improvements to technology in the market, or to enable others skilled in the art to understand the various implementations disclosed herein.

Claims

1. A current sampling device based on a two-wire circuit, characterized in that, include: The sampling circuit (1) is arranged between the high-voltage side and the low-voltage side of the line to which the current sampling device is connected; A sampling resistor (2) is connected in series in the sampling circuit (1) to form a sampling current under the potential difference between the high voltage side and the low voltage side; A compensation circuit (3) is arranged close to the sampling resistor (2) and adapted to provide a compensation current during the flow of the sampling current in the sampling circuit (1) to generate a compensation magnetic field, which is used to at least partially cancel the induced magnetic field of the sampling circuit (1). as well as A pair of voltage sampling interfaces (5) are respectively arranged at both ends of the sampling resistor (2) and are adapted to acquire the voltage signal at both ends of the sampling resistor (2).

2. The current sampling device according to claim 1, characterized in that, The compensation circuit (3) is parallel to the sampling circuit (1), and The compensation current of the compensation circuit (3) is equal in magnitude and opposite in direction to the sampling current of the sampling circuit (1).

3. The current sampling device according to claim 2, characterized in that, The distance between the compensation circuit (3) and the sampling circuit (1) is less than or equal to a predetermined distance.

4. The current sampling device according to claim 3, characterized in that, The compensation circuit (3) is connected in series with the sampling circuit (1).

5. The current sampling device according to claim 4, characterized in that, It also includes a compensation resistor (4), which is connected in series in the compensation circuit (3).

6. The current sampling device according to any one of claims 1-5, characterized in that, It also includes a detection module (6) coupled to the pair of voltage sampling interfaces (5) to determine the sampling current of the sampling circuit (1) based on the voltage signal of the pair of voltage sampling interfaces (5).

7. A current sampling device, characterized in that, include: Circuit board (7), and The current sampling device according to any one of claims 1-6 is at least partially arranged within the circuit board (7).

8. The current sampling device according to claim 7, characterized in that, The sampling circuit (1) and the compensation circuit (3) are connected in series and arranged in the same layer of the circuit board (7).

9. The current sampling device according to claim 7, characterized in that, The circuit board (7) is a multilayer circuit board, and The sampling circuit (1) and the compensation circuit (3) are respectively arranged in adjacent layers of the circuit board (7), and the sampling circuit (1) and the compensation circuit (3) are aligned in the stacking direction of the multilayer circuit board.

10. The current sampling device according to claim 7, characterized in that, One of the sampling circuit (1) and the compensation circuit (3) is arranged inside the circuit board (7), and the other is attached to the surface of the circuit board (7).

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