Broadband current sensing device

Abstract

The application discloses a wideband current detection device, and belongs to the technical field of current detection circuits.The wideband current detection device comprises a magnetic detection unit, the magnetic detection unit is provided with an air gap and a window, and the air gap and the window are communicated; a detection integrated unit, the detection integrated unit comprises a sensor device and a signal output circuit, a first end of the sensor device is electrically connected with a first end of the signal output circuit, and a second end of the sensor device is arranged in the air gap; wherein, in the case that a measured object is arranged in the window, the signal output circuit outputs a second electric signal representing an electric parameter of the measured object through the signal output circuit in response to a first electric signal output by the sensor device.

Description

Technical Field

[0001] This invention relates to the technical field of current detection circuits, and more specifically, to a broadband current detection device. Background Technology

[0002] Driven by the rapid development of power electronics, new energy, industrial automation, and smart grids, high-precision and high-reliability current detection has become a core component for stable system operation and energy efficiency optimization. Existing current detection devices can be open-loop Hall effect sensors, typically consisting of a magnetic core (ferrite or silicon steel) and a magnetic field sensor (such as a Hall element or tunnel magnetoresistive sensor) located in the air gap. However, their bandwidth is usually limited by the physical constraints of magnetic loss and the response characteristics of the magnetic field sensor. Summary of the Invention

[0003] One objective of this invention is to provide a new technical solution for a wideband current detection device.

[0004] According to a first aspect of the present invention, a broadband current detection device is provided, the device comprising:

[0005] A magnetic detection unit, wherein the magnetic detection unit has an air gap and a window, and the air gap and the window are connected;

[0006] The detection integration unit includes a sensor and a signal output circuit. The first end of the sensor is electrically connected to the first end of the signal output circuit, and the second end of the sensor is disposed in the air gap.

[0007] When the object under test is placed within the window, the signal output circuit responds to the first electrical signal output by the sensor and outputs a second electrical signal characterizing the electrical parameters of the object under test.

[0008] Optionally, there is at least one air gap and at least one sensor element, and the air gap and the sensor element are configured in a one-to-one correspondence.

[0009] Optionally, the magnetic detection unit includes a magnetic core and a coupling coil, the magnetic core and the coupling coil are concentrically arranged, the air gap of the magnetic detection unit is the magnetic core opening on the magnetic core, and the window of the magnetic detection unit is formed by the hollow space of the magnetic core and the hollow space of the coupling coil.

[0010] Optionally, the coupling coil includes at least two layers of printed circuit boards, each layer of the printed circuit board having a ring-shaped copper trace; the ring-shaped copper traces of adjacent printed circuit boards are connected in series to form the coupling coil.

[0011] Optionally, the coupling coil is disposed adjacent to the magnetic core.

[0012] Optionally, the wideband current detection device further includes a housing, the housing being provided with a loop groove, the magnetic core and the coupling coil being disposed within the loop groove, and the hollow portion of the housing located in the loop groove being used to pass through the object being measured.

[0013] Optionally, the wideband current detection device further includes an isolation plug, which is disposed in the hollow portion of the U-shaped groove.

[0014] Optionally, the signal output circuit includes a first resistor, a second resistor, and an operational amplifier;

[0015] Wherein, the first end of the first resistor serves as the first end of the signal output circuit, the first end of the second resistor is electrically connected to the low-frequency signal output end of the magnetic detection unit, the inverting input end of the operational amplifier is electrically connected to the second end of the first resistor and the second end of the second resistor respectively, the non-inverting input end of the operational amplifier is grounded, and the output end of the operational amplifier is used to output a second electrical signal characterizing the electrical parameters of the object under test.

[0016] Optionally, the signal output circuit further includes a filter resistor and a filter capacitor;

[0017] The filter resistor and the filter capacitor are both connected across the inverting input and output terminals of the operational amplifier.

[0018] Optionally, the broadband current detection device further includes a signal processing unit;

[0019] The first terminal of the signal processing unit is electrically connected to the low-frequency signal output terminal of the magnetic detection unit. The signal processing unit receives a third electrical signal output from the low-frequency signal output terminal of the magnetic detection unit. When the third electrical signal indicates that the electrical parameters of the object under test are abnormal, the signal processing unit outputs a fourth signal indicating a circuit break request to the control circuit of the broadband current detection device, so that the control circuit controls the object under test to break the circuit.

[0020] According to one embodiment of this disclosure, by setting up a magnetic detection unit and a detection integration unit, when the object under test is set within the window, the signal output circuit responds to the first electrical signal output by the sensor device and outputs a second electrical signal characterizing the electrical parameters of the object under test through the signal output circuit, thereby effectively avoiding the limitations of traditional open-loop sensors in terms of bandwidth and noise, and achieving a flat response from DC to high frequency.

[0021] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0023] Figure 1 This is a schematic diagram of the structure of a broadband current detection device according to an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of the structure of a broadband current detection device according to another embodiment of this application.

[0025] Figure 3 This is a circuit diagram of a broadband current detection device according to an embodiment of this application.

[0026] Figure 4 This is a circuit diagram of a broadband current detection device according to another embodiment of this application. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0030] 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.

[0031] 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.

[0032] This invention relates to a technical solution for a broadband current detection device. The broadband current detection device provided by this invention uses a coupling coil 3 concentrically arranged within a window of a magnetic core 2, utilizes the magnetic core 2 as a transverse magnetic shield, and employs a dual-path signal processing architecture to achieve the integration of broadband high-speed response and independent fault detection. This solves the technical problems of insufficient anti-interference capability, limited bandwidth, and inability to independently detect fault characteristics in current sensors in related technologies.

[0033] The wideband current detection device of this invention can be applied to fields such as power converter control, motor drive, battery management, charging facilities and power distribution systems, and is particularly suitable for current detection and protection of wide bandgap power semiconductor devices such as silicon carbide and gallium nitride.

[0034] In some embodiments, such as Figure 2 As shown, the broadband current detection device may include:

[0035] A magnetic detection unit, which has an air gap and a window, and the air gap and the window are connected.

[0036] The detection integration unit includes a sensor 5 and a signal output circuit 4. The first end of the sensor 5 is electrically connected to the first end of the signal output circuit 4, and the second end of the sensor 5 is disposed in the air gap.

[0037] When the object under test is set within the window, the signal output circuit 4 responds to the first electrical signal output by the sensor 5 and outputs a second electrical signal characterizing the electrical parameters of the object under test.

[0038] In this embodiment, by setting up a magnetic detection unit and a detection integration unit, when the object under test is set within the window, the signal output circuit 4 responds to the first electrical signal output by the sensor device 5 and outputs a second electrical signal characterizing the electrical parameters of the object under test through the signal output circuit 4, so as to effectively avoid the limitations of traditional open-loop sensors in terms of bandwidth and noise, and can achieve a flat response from DC to high frequency.

[0039] In this embodiment, as Figure 2 As shown, the detection integrated unit includes a sensing printed circuit board, on which a sensor 5 is mounted. The sensor 5 is a Hall effect sensor. The second end of the sensor 55 is disposed within the air gap of the magnetic core 2, and is used to sense the DC and low-frequency magnetic flux generated by the object being measured. The first end of the sensor 55 is electrically connected to the first end of the signal output circuit 4 via a wire.

[0040] In some embodiments, there is at least one air gap and at least one sensor element 5, and the air gap and the sensor element 5 are configured in a one-to-one correspondence.

[0041] In this embodiment, the broadband current detection device can employ a single-air-gap configuration or a dual-air-gap configuration. The single-air-gap configuration is suitable for medium current measurements (rated current less than 700 amperes), has a compact structure, and is less expensive. Figure 2 As shown, the dual air gap configuration is suitable for high current measurement (rated current greater than 1000 amperes). By sharing the magnetic flux through the two air gaps, the risk of magnetic circuit saturation is reduced, and the linearity and reliability of the measurement are improved.

[0042] In some embodiments, such as Figure 2 As shown, the magnetic detection unit includes a magnetic core 2 and a coupling coil 3. The magnetic core 2 and the coupling coil 3 are arranged concentrically. The air gap of the magnetic detection unit is the opening of the magnetic core 2 on the magnetic core 2. The window of the magnetic detection unit is formed by the hollow space of the magnetic core 2 and the hollow space of the coupling coil 3.

[0043] In this embodiment, the air gap in the magnetic core is interconnected with the overall window of the magnetic detection unit. This air gap allows for the installation of sensor components, enabling integrated placement of sensing elements and simplifying the overall structural volume. It also allows the magnetic field to be smoothly conducted and circulated through the connecting channel, optimizing the magnetic field propagation path, reducing magnetic field leakage loss, and improving magnetic field utilization. Furthermore, it facilitates the uniform distribution of the magnetic field within the window space, further ensuring the accuracy and response sensitivity of the magnetic detection unit's signal acquisition.

[0044] In this embodiment, the magnetic core 2 is made of nanocrystalline material and has a ring structure. The magnetic core 2 has a magnetic core opening to accommodate the sensor 5.

[0045] In some embodiments, the coupling coil 3 may include at least two layers of printed circuit boards, each layer of printed circuit board having a ring-shaped copper trace. The ring-shaped copper trace can be understood as the printed circuit boards of each layer being connected to form a ring. The ring-shaped copper traces of adjacent printed circuit boards are connected in series. The ring-shaped copper trace can be such that the center of each individual coil of the coupling coil 3 does not coincide with the hollow space of the coupling coil 3, but the center of all coils as a whole coincides with the hollow cavity.

[0046] In this embodiment, the magnetic core and the coupling coil adopt a concentric arrangement structure, which can make the magnetic field generated by the current-carrying conductor uniformly distributed in the circumference of the magnetic core and the coupling coil, effectively reducing the detection error caused by magnetic field deviation, improving the consistency of magnetic field coupling, ensuring the stable and uniform induced magnetic flux of the coupling coil, greatly improving the current detection accuracy and detection stability, while simplifying the overall assembly alignment structure and reducing the difficulty of device assembly.

[0047] In this embodiment, the coupling coil 3 is manufactured using a multilayer printed circuit board (PCB) process, with each PCB layer having a ring-shaped copper trace. The ring-shaped copper traces of adjacent PCBs are connected in series to form a Rogowski coil. The coupling coil 3 is positioned adjacent to the magnetic core 2, and is concentrically positioned with the object under test (current-carrying conductor), arranged inside the window of the magnetic core 2.

[0048] In this embodiment, the coupling coil 3 is manufactured using a multilayer printed circuit board (PCB) process, which offers advantages over traditional wire winding processes, including lower cost, less temperature drift, and ease of mass production. The toroidal copper traces on the PCB are connected in series to form a Rogowski coil, allowing adjustment of the coil turns and trace dimensions according to different current range requirements. One or more layers of the PCB can be dedicated to forming an electrostatic shielding layer, further enhancing anti-interference capabilities.

[0049] In some embodiments, the coupling coil 3 is disposed adjacent to the magnetic core 2.

[0050] In this embodiment, by placing the coupling coil 3 adjacent to the magnetic core 2, the immunity of the magnetic core 2 to the coupling coil 3 can be effectively improved. The coupling coil is arranged inside the window of the magnetic core and adjacent to it, which can minimize the magnetic field transmission distance, enhance the magnetic field coupling efficiency between the magnetic core and the coupling coil, and reduce energy attenuation during magnetic field transmission. Combined with the concentric layout structure, it can accurately capture the alternating magnetic field generated by the current-carrying conductor, enabling the Rogowski coil to accurately sense the induced electromotive force, thus improving the real-time performance and reliability of high-current and alternating current detection.

[0051] In some embodiments, the broadband current detection device further includes a housing 1, which is provided with a groove. The magnetic core and the coupling coil are both disposed in the groove. The hollow portion of the housing 1 located in the groove is used to pass through the object being measured.

[0052] In some examples, the magnetic core 2 can be attached to the first ring wall of the ring groove, and the coupling coil 3 can be attached to the second ring wall of the ring groove, so that the magnetic core 2 and the coupling coil 3 are confined within the housing 1. The magnetic core 2 and the coupling coil 3 can also be directly fixed to the housing 1 by means of direct bonding or other fixing methods.

[0053] In this embodiment, as Figure 2 As shown, by setting the housing 1, the magnetic core 2 and the coupling coil 3 can be confined in the housing 1 to maintain their original state, which effectively improves the service life of the magnetic core 2 and the coupling coil 3.

[0054] In some embodiments, the broadband current detection device further includes an isolation plug 6, which is disposed in the hollow portion of the U-shaped groove.

[0055] In this embodiment, as Figure 1 As shown, the housing 1 can be detachably connected to the isolation plug 6. The detachable structure can be a snap-fit ​​structure to significantly increase the creepage distance and clearance for high-voltage applications without changing the housing 1.

[0056] In some embodiments, the signal output circuit 4 includes a first resistor R1, a second resistor R2, and an operational amplifier Ua;

[0057] In this circuit, the first end of the first resistor R1 serves as the first end of the signal output circuit 4, the first end of the second resistor R2 is electrically connected to the low-frequency signal output end of the magnetic detection unit, the inverting input end of the operational amplifier Ua is electrically connected to the second end of the first resistor R1 and the second end of the second resistor R2, the non-inverting input end of the operational amplifier Ua is grounded, and the output end OUT_1 of the operational amplifier Ua is used to output a second electrical signal characterizing the electrical parameters of the object under test.

[0058] In this embodiment, the low-frequency signal output terminal of the magnetic detection unit corresponds to sensor 5, wherein the sensor is a Hall effect sensor, that is, the low-frequency channel is a Hall channel. The first terminal of the signal output circuit corresponds to coupling coil 3, wherein coupling coil 3 is a Rogowski coil, that is, the Rogowski coil corresponds to the high-frequency channel.

[0059] In this embodiment, by setting the signal output circuit 4, the current of the object under test can be acquired, so as to achieve a flat response of the broadband current detection device from DC to high frequency.

[0060] In some embodiments, the signal output circuit 4 further includes a filter resistor R3 and a filter capacitor Ca;

[0061] In this circuit, both the filter resistor R3 and the filter capacitor Ca are connected across the inverting input and output terminals of the operational amplifier Ua.

[0062] In this embodiment, the signal output circuit 4 further includes a filter resistor R3 and a filter capacitor Ca. Both the filter resistor R3 and the filter capacitor Ca are connected across the inverting input and output of the operational amplifier Ua, forming a first-order low-pass filter. This filter circuit is used to suppress high-frequency noise and ensure the stability of the first signal path output.

[0063] In some examples, the signal output circuit 4 includes resistors R4, R5, R8, R14, R17, R13, R18, R23, R10, R37, R38, R39, capacitors C1, C8, C16, C17, C18, C5, C10, C9, and voltage regulator D10. The series resistors R37, R38, R39, capacitor C18, variable resistor P2, operational amplifier IC1B, and operational amplifier IC1A are connected together. The other end of resistor R37 is connected to coupling coil 3. Resistors R4, R8, R5, capacitor C1, operational amplifier IC1B, resistor R14, and capacitor C8 are configured to convert the signal output from the low-frequency signal output terminal of the magnetic detection unit, and then output it to resistors R17, capacitor C16, variable resistor P2, operational amplifier IC1A, capacitor C5, resistors R10, R13, capacitor C9, resistors R18, and resistor R23 for further processing.

[0064] In some embodiments, such as Figure 3 As shown, the wideband current detection device also includes a signal processing unit K1;

[0065] The first terminal of the signal processing unit K1 is electrically connected to the low-frequency signal output terminal of the magnetic detection unit. The signal processing unit K1 receives the third electrical signal output from the low-frequency signal output terminal of the magnetic detection unit. When the third electrical signal indicates that the electrical parameters of the object under test are abnormal, the signal processing unit K1 outputs a fourth signal indicating a circuit breaker request to the control circuit of the broadband current detection device so that the control circuit controls the object under test to disconnect the circuit.

[0066] In this embodiment, as Figure 4 As shown, the signal processing unit K1 includes resistors R40-R46, capacitors Ca9, C20, C22, C23, C24, and C26, and an operational amplifier U1. Resistors R41 and R40 are connected in series. The other end of resistor R41 is connected to coupling coil 3, and the other end of resistor R40 is connected to the inverting input of operational amplifier U1. Capacitor C26 is connected between resistor R41 and ground. Resistor R47 is connected between the bottom stage and the non-inverting input of operational amplifier U1. The output of operational amplifier U1 is electrically connected to capacitor C23 and then electrically connected to the control circuit of the broadband current detection device. Resistors R42 and R43 are connected in series between the inverting input and output of operational amplifier U1. Capacitor C24 is connected between the inverting input and output of operational amplifier U1. Capacitor C22 and resistor R44 are connected in series. The other end of capacitor C22 is electrically connected to resistor R42, and the other end of resistor R44 is grounded.

[0067] In this embodiment, the low-frequency signal output terminal of the magnetic detection unit corresponds to the output terminal of the coupling coil 3.

[0068] In this embodiment, the control circuit can be an existing control chip, and the control chip can control the tested object to stop running.

[0069] In this embodiment, the signal processing unit K1 can be a signal conditioning and / or processing circuit, or a direct-through circuit. When the amplitude of the fourth electrical signal exceeds a preset threshold, the low-frequency signal of the magnetic detection unit outputs a third electrical signal, and the signal processing unit K1 determines whether the electrical parameters of the object under test are abnormal. If the fourth electrical signal indicates an abnormality in the electrical parameters of the object under test, such as detecting an arc fault or insulation breakdown, a fifth signal indicating a circuit-breaking request is output to the control circuit of the broadband current detection device, so that the control circuit controls the object under test to disconnect from the circuit, thereby achieving the protection function.

[0070] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A broadband current detection device, characterized in that, The device includes: A magnetic detection unit, wherein the magnetic detection unit has an air gap and a window, and the air gap and the window are connected; The detection integration unit includes a sensor and a signal output circuit. The first end of the sensor is electrically connected to the first end of the signal output circuit, and the second end of the sensor is disposed in the air gap. When the object under test is placed within the window, the signal output circuit responds to the first electrical signal output by the sensor and outputs a second electrical signal characterizing the electrical parameters of the object under test.

2. The broadband current detection device according to claim 1, characterized in that, There is at least one air gap and at least one sensor, and the air gap and the sensor are configured in a one-to-one correspondence.

3. The broadband current detection device according to claim 1, characterized in that, The magnetic detection unit includes a magnetic core and a coupling coil, the magnetic core and the coupling coil are concentrically arranged, the air gap of the magnetic detection unit is the magnetic core opening on the magnetic core, and the window of the magnetic detection unit is formed by the hollow space of the magnetic core and the hollow space of the coupling coil.

4. The broadband current detection device according to claim 3, characterized in that, The coupling coil includes at least two layers of printed circuit boards, each layer of which has a ring-shaped copper trace; the ring-shaped copper traces of adjacent printed circuit boards are connected in series to form the coupling coil.

5. The broadband current detection device according to claim 3, characterized in that, The coupling coil is positioned adjacent to the magnetic core.

6. The broadband current detection device according to claim 3, characterized in that, The broadband current detection device also includes a housing, which is provided with a groove. The magnetic core and the coupling coil are both disposed in the groove, and the hollow part of the housing located in the groove is used to pass through the object being measured.

7. The broadband current detection device according to claim 6, characterized in that, The broadband current detection device also includes an isolation plug, which is disposed in the hollow portion of the U-shaped groove.

8. The broadband current detection device according to claim 1, characterized in that, The signal output circuit includes a first resistor, a second resistor, and an operational amplifier; Wherein, the first end of the first resistor serves as the first end of the signal output circuit, the first end of the second resistor is electrically connected to the low-frequency signal output end of the magnetic detection unit, the inverting input end of the operational amplifier is electrically connected to the second end of the first resistor and the second end of the second resistor respectively, the non-inverting input end of the operational amplifier is grounded, and the output end of the operational amplifier is used to output a second electrical signal characterizing the electrical parameters of the object under test.

9. The broadband current detection device according to claim 8, characterized in that, The signal output circuit also includes a filter resistor and a filter capacitor; The filter resistor and the filter capacitor are both connected across the inverting input and output terminals of the operational amplifier.

10. The broadband current detection device according to claim 8, characterized in that, The broadband current detection device also includes a signal processing unit; The first terminal of the signal processing unit is electrically connected to the low-frequency signal output terminal of the magnetic detection unit. The signal processing unit receives a third electrical signal output from the low-frequency signal output terminal of the magnetic detection unit. When the third electrical signal indicates that the electrical parameters of the object under test are abnormal, the signal processing unit outputs a fourth signal indicating a circuit break request to the control circuit of the broadband current detection device, so that the control circuit controls the object under test to break the circuit.

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