A current measurement system and method based on quantum magnetic field detection technology

Abstract

The application belongs to the technical field of electric power detection, and discloses a current measurement system and method based on quantum magnetic field detection technology, which comprises a hollow metal pipe, two ends of which are connected with current-carrying wires so that the magnetic field generated by the current to be measured in the current-carrying wires is attenuated in the hollow metal pipe; a quantum magnetic sensor, which is arranged at the center of the hollow metal pipe and is used for measuring the magnetic field intensity at the position; an excitation module, which is connected with the quantum magnetic sensor and provides an excitation source for the quantum magnetic sensor; and a signal processing and display module, which receives the magnetic field intensity measured by the quantum magnetic sensor and converts the magnetic field intensity into a current value; wherein the current-carrying wires are connected to the hollow metal pipe in a double-end two-side connection mode, both ends of the hollow metal pipe are provided with two connection ends, and each connection end is connected with a current-carrying wire. The double-end two-side connection mode can effectively reduce the intensity of the magnetic field generated by the current in the hollow metal pipe, and expand the current measurement range under the condition that the magnetic field intensity measurement range of the quantum magnetic sensor is fixed.

Description

Technical Field

[0001] This invention belongs to the field of power detection technology, specifically relating to a current measurement system and method based on quantum magnetic field detection technology. Background Technology

[0002] Accurate current measurement is a core technological aspect of ensuring the safe and stable operation of power systems, real-time monitoring of equipment status, precise energy consumption assessment, fault early warning, and the construction of smart grids. Currently, power systems widely use current transformers based on Faraday's law of electromagnetic induction for current measurement. These devices rely on coil and magnetic core structures, and in practical applications, they exhibit drawbacks such as small dynamic range, poor linearity, limited measurement accuracy (especially in the range limits), and susceptibility to magnetic saturation. Furthermore, current transformers are bulky, heavy, and cannot be used for DC signal measurement, making them unsuitable for ultra-high voltage DC measurements.

[0003] To overcome some limitations of traditional current transformers, novel current measuring devices based on Hall effect magnetic sensors and fluxgate sensors have emerged. The core problem with these devices is that they employ an indirect measurement method that converts magnetic field information into a voltage signal. The measurement accuracy heavily relies on the sensor's own material parameters (such as the Hall coefficient of the Hall element and the thickness of the dielectric). These parameters are easily affected by factors such as manufacturing processes, material aging, and external circuit noise, leading to limitations in measurement accuracy and stability. Furthermore, the measurement range of these sensors typically still depends on the coil and core structure, and they are similarly susceptible to the effects of core nonlinearity and hysteresis.

[0004] Chinese patent document CN118011072A discloses a wide-range current measurement method based on a high-precision weak magnetic field sensor. This technology proposes to utilize a hollow metal tube structure, based on the skin effect, to attenuate the strong magnetic field generated by a large current into a weak magnetic field in the central region of the tube, thus eliminating the dependence on traditional coil and magnetic core structures and achieving wide-range current measurement. However, this scheme is limited by the accuracy of the magnetic sensor used (such as a vector magnetic sensor), and its current detection accuracy is usually only ≥0.1%, which is difficult to meet the growing demand for high-precision metrology. Moreover, vector magnetic sensors are prone to introducing vibration noise, resulting in poor measurement stability in complex industrial environments. Secondly, in this technology, the connection between the wire under test and the hollow metal tube is single-ended and single-sided input, which limits the extension of the current detection range and makes it impossible to detect small currents. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a current measurement system and method based on quantum magnetic field detection technology. The current-carrying wire and the hollow metal tube are connected in a double-ended, two-sided manner, which can effectively reduce the intensity of the magnetic field generated by the current inside the hollow metal tube, thereby expanding the current measurement range while keeping the magnetic field intensity measurement range of the quantum magnetic sensor fixed.

[0006] This invention provides the following technical solution:

[0007] The first objective of this invention is to provide a current measurement system based on quantum magnetic field detection technology, comprising:

[0008] A hollow metal tube with current-carrying wires connected to both ends, so that the magnetic field generated by the current to be measured in the current-carrying wires is attenuated inside the hollow metal tube.

[0009] A quantum magnetic sensor, placed in the central region inside a hollow metal tube, is used to measure the magnetic field strength at its location.

[0010] The excitation module is connected to the quantum magnetic sensor and provides an excitation source for the quantum magnetic sensor.

[0011] The signal processing and display module receives the magnetic field strength measured by the quantum magnetic sensor and converts the magnetic field strength into a current value;

[0012] The current-carrying wire is connected to the hollow metal tube in a double-ended, two-sided manner. Each end of the hollow metal tube is equipped with a pair of access terminals, and each access terminal is connected to a current-carrying wire.

[0013] The current-carrying conductor is connected to the hollow metal tube via a double-ended connection method, which effectively reduces the intensity of the magnetic field generated by the current within the hollow metal tube, thereby expanding the current measurement range while maintaining a fixed magnetic field strength measurement range for the quantum magnetic sensor. Simultaneously, the double-ended connection method also improves the uniformity of the magnetic field within the hollow metal tube, effectively enhancing the stability of the quantum magnetic sensor's detection.

[0014] As a further improvement of the present invention, the cross-section of the hollow metal tube is axisymmetric. This ensures that the current is symmetrically distributed on the tube wall, thereby allowing the magnetic field generated by the current to be symmetrically attenuated and canceled in the central region of the tube due to the skin effect.

[0015] As a further improvement of the present invention, a pair of access ends located at the same end of the hollow metal tube are situated in the same cross-section and symmetrically distributed along the axis of symmetry of the cross-section. This further optimizes the uniformity of the magnetic field in the central region of the pipe, thereby improving the accuracy and stability of current measurement.

[0016] As a further improvement of the present invention, the quantum magnetic sensor is connected to the excitation module and the signal processing via optical fiber, coaxial cable, or waveguide. In complex environments, a coaxial cable is chosen.

[0017] As a further improvement of the present invention, the quantum magnetic sensor is fixed at the center of the hollow metal tube by a bracket made of non-magnetic material. Using a non-magnetic material (such as titanium alloy) to make the bracket avoids the magnetism of the fixing device itself from disturbing the measured magnetic field environment.

[0018] As a further improvement of the present invention, the axial length, inner diameter and outer diameter of the hollow metal tube are configured such that the strength of the magnetic field generated by the current to be measured in the central region of the hollow metal tube matches the measurement range of the quantum magnetic sensor.

[0019] As a further improvement of the present invention, the excitation module and the signal processing and display module are located away from the magnetic field inside the hollow metal tube.

[0020] As a further improvement of the present invention, the quantum magnetic sensor includes an optically pumped atomic magnetometer, a nitrogen-vacancy diamond atomic magnetometer, a nucleon precession magnetometer, and a molecular magnetometer.

[0021] As a further improvement of the present invention, when the quantum magnetic sensor is an optically pumped atomic magnetometer, the propagation direction of the pump light inside the optically pumped atomic magnetometer is neither parallel nor perpendicular to the direction of the magnetic field.

[0022] There are two dead zones in the optically pumped magnetometer during the measurement process. One dead zone is when the pump light is perpendicular to the direction of the static magnetic field, and the other dead zone is when the pump light is parallel to the direction of the static magnetic field. In these two cases, the signal output of the optically pumped magnetometer will drop significantly or fail directly, thus affecting the accuracy of the measurement. Therefore, it is necessary to avoid these two directions to ensure that the optically pumped magnetometer can work normally.

[0023] The second objective of this invention is to provide a current measurement method based on quantum magnetic field detection technology, implemented using the aforementioned current measurement system, comprising:

[0024] The standard current source is connected to the hollow metal tube via a double-ended connection.

[0025] By controlling the output of a standard current source at different current values, the magnetic field strength values ​​measured by the quantum magnetic sensor at each current value are obtained, and a linear standard curve of current-magnetic field is established by fitting.

[0026] Disconnect the standard current source, connect the current-carrying wire to be tested to the hollow metal tube in the same way, obtain the magnetic field strength value measured by the quantum magnetic sensor, and obtain the current value to be tested based on the current-magnetic field linear standard curve.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The current-carrying conductor is connected to the hollow metal tube via a double-ended connection method, which effectively reduces the intensity of the magnetic field generated by the current within the hollow metal tube, thereby expanding the current measurement range while maintaining a fixed magnetic field strength measurement range for the quantum magnetic sensor. Simultaneously, the double-ended connection method also improves the uniformity of the magnetic field within the hollow metal tube, effectively enhancing the stability of the quantum magnetic sensor's detection. Attached Figure Description

[0029] Figure 1 A schematic diagram of the overall structure of the current measurement system provided in this application;

[0030] Figure 2 This is a schematic diagram of the structure of a quantum magnetic sensor;

[0031] Figure 3 A schematic diagram of a single-end current injection method;

[0032] Figure 4 This is a schematic diagram of a double-ended current injection method.

[0033] Figure 5 This is a schematic diagram of the raw data of the magnetic field strength measured by the quantum magnetic sensor under different current values ​​when using the double-ended current injection method.

[0034] Figure 6 To Figure 5 A schematic diagram of the current-magnetic field linear standard curve obtained by linear fitting the original data;

[0035] Figure 7 This is a schematic diagram of the current-magnetic field linear standard curves obtained by using two different current injection methods in Experiment 1: single-ended input from one side and double-ended input from both sides.

[0036] Figure 8 This is a schematic diagram of the magnetic field distribution inside the hollow metal tube obtained by using a single-end, one-sided current injection method in Experiment 2.

[0037] Figure 9 This is a schematic diagram of the magnetic field distribution inside the hollow metal tube obtained by using the double-ended input current injection method in Experiment 2.

[0038] Explanation of reference numerals in the attached figures: 1. Quantum magnetic sensor; 11. Atomic gas cell; 12. Self-excited coil; 13. Self-excited control module; 2. Hollow metal tube; 3. Current-carrying wire; 4. Excitation module; 5. Signal processing and display module. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The present invention will now be described in further detail with reference to the accompanying drawings:

[0041] like Figure 1 As shown, this embodiment provides a current measurement system based on quantum magnetic field detection technology, including:

[0042] Hollow metal tube 2 is made of aluminum, copper or other metal materials with good conductivity. Its cross-section is an axisymmetric figure. Its two ends are connected to current-carrying wires 3 so that the magnetic field generated by the current to be measured in the current-carrying wires 3 is attenuated in the hollow metal tube.

[0043] The quantum magnetic sensor 1 is fixed in the central region inside the hollow metal tube 2 by a bracket made of non-magnetic material (such as titanium alloy) to measure the magnetic field strength at its location.

[0044] Excitation module 4 is connected to quantum magnetic sensor 1 and provides an excitation source for quantum magnetic sensor 1;

[0045] The signal processing and display module 5 receives the magnetic field strength measured by the quantum magnetic sensor 1 and converts the magnetic field strength into a current value.

[0046] The quantum magnetic sensor is connected to the excitation module, signal processing and display module via optical fiber, coaxial cable, or waveguide. Since optical fibers are easily damaged, coaxial cables are chosen for complex environments. Furthermore, to avoid the influence of the internal magnetic field of the hollow metal tube on the excitation module and signal processing and display module, these modules are placed away from the internal magnetic field of the hollow metal tube, and can be placed at opposite ends of the tube.

[0047] Specifically, quantum magnetic sensor 1 is a general term for magnetic field sensors based on the quantum magnetic field effect. The measurement principle is to convert the magnetic field strength measurement into the spectral line frequency measurement. Quantum magnetic sensor 1 includes optically pumped atomic magnetometer, nitrogen vacancy (NV) diamond atomic magnetometer, nucleon precession magnetometer and molecular magnetometer.

[0048] In this embodiment, the quantum magnetic sensor 1 is an optically pumped atomic magnetometer, the structure of which is as follows: Figure 2As shown, it is connected to the excitation module 4 and the signal processing and display module 5 via optical fiber. The atomic gas chamber 11 in the quantum magnetic sensor 1 is filled with atomic gas, and a self-excited coil 12 surrounds the atomic gas chamber 11. The laser output from the optical fiber is emitted from one end of the atomic gas chamber 11 to the other end through free space, and is received by the photodetector of the self-excited control module 13. After signal amplification and phase shifting, it forms a conditioning circuit with the self-excited coil 12, i.e., a self-excited oscillation control circuit. When the radio frequency generated by the self-excited coil 12 resonates with the atomic spectral lines, the entire circuit forms positive feedback. Its signal frequency and the magnetic field strength of the atomic gas chamber 11 satisfy the following formula:

[0049]

[0050] in, The resonant frequency, The atomic gyromagnetic ratio of an atomic gas. The magnetic field strength is the magnetic field strength at the location measured by the quantum magnetic sensor.

[0051] Before measurement, the light source in the excitation module 4 is stabilized in frequency and controlled in temperature to ensure that the laser outputs sufficient power and that its wavelength center frequency is aligned with the working spectrum line of the quantum gas quantum effect of the quantum magnetic sensor 1. Then, the laser is adjusted by the optical devices in the excitation module 4 to achieve the best collimation and polarization state for quantum magnetic measurement. Next, the laser is input into the quantum magnetic sensor 1 through the optical fiber coupler.

[0052] Because optically pumped magnetometers have two dead zones during measurement—one where the pump light is perpendicular to the static magnetic field and the other where it is parallel to the static magnetic field—the signal output of the optically pumped magnetometer will significantly decrease or even fail, thus affecting the accuracy of the measurement. Therefore, it is necessary to control the propagation direction of the pump light inside the optically pumped magnetometer to be neither parallel nor perpendicular to the magnetic field direction.

[0053] In this embodiment, the current-carrying wire 3 is connected to the hollow metal tube 2 by connecting to both ends. Specifically, each end of the hollow metal tube 2 is provided with a pair of connection ends, and the pair of connection ends located at the same end of the hollow metal tube 2 are located in the same cross section and are symmetrically distributed along the axis of symmetry of the cross section. Each connection end is connected to a current-carrying wire. Figure 4 This is a schematic diagram of a hollow metal tube 2 connected to a current-carrying wire at one end.

[0054] By utilizing the high-current-weak-magnetic-field conversion mechanism of a symmetrical hollow metal tube 2, the difficulty that the magnetic field measurement range of the quantum magnetic sensor 1 cannot directly meet the requirements of high-current measurement is overcome. The skin effect exists when current is transmitted through a conductor. By utilizing the conductor's symmetry and the attenuation of the magnetic field generated by the high current by surface eddy currents, a weak magnetic space with a magnetic field strength close to zero is formed inside the symmetrical hollow metal tube 2 when the high current is transmitted.

[0055] To ensure that the strength of the magnetic field generated by the current under test in the central region of the hollow metal tube 2 matches the measurement range of the quantum magnetic sensor 1, the axial length, inner diameter, and outer diameter of the hollow metal tube 2 need to be designed. In this embodiment, the hollow metal tube 2 is cylindrical, and the relationship between the magnetic field strength in its internal central region and its structural dimensions and current is as follows:

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] in It is the magnetic permeability in free space, that is, the magnetic permeability in a hollow metal tube; It is the magnitude of the current flowing through a hollow metal tube with a symmetrical structure; It is the axial length of a hollow metal tube with a symmetrical structure; It is the outer radius of a hollow metal tube with a symmetrical structure; It is the inner radius of a hollow metal tube with a symmetrical structure; It is the longitudinal distance from the center of the quantum magnetic sensor to the center point of the central axis of the hollow metal tube; It refers to the inner and outer radii of a hollow metal tube with a symmetrical structure; It is the distance from the quantum magnetic sensor to the upper surface of the hollow metal tube. It is the distance from the quantum magnetic sensor to the lower end face of the hollow metal tube. It is a quantum magnetic sensor to The distance; It is a quantum magnetic sensor to and Distance in the opposite direction; It is a position vector and The angle between them; It is a position vector and The angle between them; It is the axial distance from the quantum magnetic sensor to the center point of the central axis of the hollow metal tube.

[0063] Based on the above formula, by adjusting... , , , This allows for the alteration of the magnetic field inside a hollow metal tube, thereby matching the measurement range of the quantum magnetic sensor and enabling the measurement of large currents in different ranges.

[0064] This embodiment provides a current measurement method based on quantum magnetic field detection technology, implemented based on the aforementioned current measurement system, including:

[0065] The standard current source is connected to the hollow metal tube via a double-ended connection.

[0066] By controlling the output of a standard current source at different current values, the magnetic field strength values ​​measured by the quantum magnetic sensor at each current value are obtained, and a linear standard curve of current-magnetic field is established by fitting.

[0067] Disconnect the standard current source, connect the current-carrying wire to be tested to the hollow metal tube in the same way, obtain the magnetic field strength value measured by the quantum magnetic sensor, and obtain the current value to be tested based on the current-magnetic field linear standard curve.

[0068] Theoretical calculations show that the current and magnetic field in a symmetrical hollow metal tube have a linear relationship. A plot of the vertical axis representing the current value is then constructed. The horizontal axis represents the magnetic field strength. In a two-dimensional rectangular coordinate system, each of the above measurements... The points formed All of them will fall on the same oblique line in the coordinate system. By using the multi-point fitting method, the standard magnetic field strength-current conversion curve in this coordinate system can be accurately plotted.

[0069] The raw data of the magnetic field strength measured by the quantum magnetic sensor under different current values ​​are as follows: Figure 5 As shown. Figure 5 In the graph, the horizontal axis represents the gradually increasing alternating current output by a standard alternating current source over a certain period of time, and the vertical axis represents the magnetic field value measured by the quantum magnetic sensor. Because the current is alternating current, the magnetic field value measured by the quantum magnetic sensor expands both vertically, presenting as an expanding step-like graph. Through analysis of... Figure 5 Linear fitting was performed on the original data graph to obtain the following result: Figure 6 The current-magnetic field linear standard curve is shown.

[0070] The effects of the present invention are demonstrated through specific experiments below.

[0071] Experiment 1:

[0072] Two identical hollow aluminum tubes, each 1.5m long, 30cm in inner diameter, and 21mm in wall thickness, were selected. A light-pumped magnetometer was placed in the middle of the interior of each tube. Using two identical standard current sources, one of the hollow aluminum tubes was injected with current via a single-end, one-sided input method (e.g.,...). Figure 3 As shown), the other hollow aluminum tube uses a double-ended current injection method (the method provided by this invention, such as...). Figure 4 (As shown). Two identical standard current sources were controlled to output the same current value. The magnetic field strength amplitude output by the optically pumped magnetometer inside the two hollow aluminum tubes was recorded for each current value. The current-magnetic field linear standard curve is shown below. Figure 7 As shown in the figure, the vertical axis represents the magnetic field strength amplitude, and the horizontal axis represents the current value injected into the hollow aluminum tube.

[0073] pass Figure 7 It can be seen that when the output current value is less than 30A, that is, when the current injected into the two hollow aluminum tubes is less than 30A, under the condition that the measurement range of the quantum magnetic sensor is fixed, the optically pumped magnetometer inside the hollow aluminum tube with single-end input can no longer measure the magnetic field, while the optically pumped magnetometer inside the hollow aluminum tube with double-end input can still measure the magnetic field. Therefore, it can be concluded that using the double-end input current injection method can effectively reduce the magnetic field strength generated by the current inside the hollow conductor tube, thereby increasing the current measurement range under the condition that the measurement range of the quantum magnetic sensor is fixed.

[0074] Experiment 2:

[0075] A 2m long hollow aluminum tube with an inner diameter of 56cm and an outer diameter of 60cm was injected with a 25A, 50Hz current using a single-end, one-sided current injection method. Ten rows of quantum magnetic sensors were soldered onto a PCB board. The PCB board with the quantum magnetic sensors was then moved from one end of the hollow aluminum tube to the other, and the magnetic field amplitude measured by the quantum magnetic sensors inside the hollow aluminum tube was recorded. The results are as follows: Figure 8 As shown.

[0076] A 2m long hollow aluminum tube with an inner diameter of 56cm and an outer diameter of 60cm was injected with a 25A, 50Hz current using a double-ended current injection method. Ten rows of quantum magnetic sensors were soldered onto a PCB board. The PCB board with the quantum magnetic sensors was then moved from one end of the hollow aluminum tube to the other, and the magnetic field amplitude measured by the quantum magnetic sensors inside the hollow aluminum tube was recorded. The results are as follows: Figure 9 As shown.

[0077] By comparison Figure 8 and Figure 9 It can be clearly seen that the current injection method with input from both ends can effectively improve the uniformity of the magnetic field inside the hollow metal tube. A more uniform magnetic field can improve the working stability of the quantum magnetic sensor, thereby helping the quantum magnetic sensor to work normally.

[0078] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A current measurement system based on quantum magnetic field detection technology, characterized in that, include: A hollow metal tube with current-carrying wires connected to both ends, so that the magnetic field generated by the current to be measured in the current-carrying wires is attenuated inside the hollow metal tube. A quantum magnetic sensor is placed in the central region inside a hollow metal tube, with a distance between the radial direction of the hollow metal tube and the central axis of the hollow metal tube, and is used to measure the magnetic field strength at its location. The excitation module is connected to the quantum magnetic sensor and provides an excitation source for the quantum magnetic sensor. The signal processing and display module receives the magnetic field strength measured by the quantum magnetic sensor and converts the magnetic field strength into a current value; The current-carrying wire is connected to the hollow metal tube in a double-ended, two-sided manner. Each end of the hollow metal tube has a pair of connection ends, and each connection end is connected to a current-carrying wire. The cross-section of the hollow metal tube is circular. The pair of connection ends located at the same end of the hollow metal tube are on the same cross-section and are symmetrically distributed along the axis of symmetry of the cross-section.

2. The current measurement system according to claim 1, characterized in that, The quantum magnetic sensor is connected to the excitation module via optical fiber, coaxial cable, or waveguide. The quantum magnetic sensor is connected to the signal processing and display module via optical fiber or coaxial cable.

3. The current measurement system according to claim 1, characterized in that, The quantum magnetic sensor is fixed in the central region inside a hollow metal tube by a bracket made of non-magnetic material.

4. The current measurement system according to claim 1, characterized in that, The axial length, inner diameter, and outer diameter of the hollow metal tube are configured such that the strength of the magnetic field generated by the current to be measured in the central region of the hollow metal tube matches the measurement range of the quantum magnetic sensor.

5. The current measurement system according to claim 1, characterized in that, The excitation module and the signal processing and display module are located away from the magnetic field inside the hollow metal tube.

6. The current measurement system according to claim 1, characterized in that, The quantum magnetic sensor includes an optically pumped atomic magnetometer, a nitrogen-vacancy diamond atomic magnetometer, and a nuclear precession magnetometer.

7. The current measurement system according to claim 6, characterized in that, When the quantum magnetic sensor is an optically pumped atomic magnetometer, the propagation direction of the pump light inside the optically pumped atomic magnetometer is neither parallel nor perpendicular to the direction of the magnetic field.

8. A current measurement method based on quantum magnetic field detection technology, implemented using the current measurement system according to any one of claims 1 to 7, characterized in that, include: The standard current source is connected to the hollow metal tube via a double-ended connection. By controlling the output of a standard current source at different current values, the magnetic field strength values ​​measured by the quantum magnetic sensor at each current value are obtained, and a linear standard curve of current-magnetic field is established by fitting. Disconnect the standard current source, connect the current-carrying wire to be tested to the hollow metal tube in the same way, obtain the magnetic field strength value measured by the quantum magnetic sensor, and obtain the current value to be tested based on the current-magnetic field linear standard curve.

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