Double-magnetic-core current detection structure and current detection method

Abstract

The invention relates to the technical field of direct current systems, in particular to a double-magnetic-core current detection structure and a current detection method. The method comprises the following steps: acquiring an induced electromotive force signal detected by a signal detector in the dual-magnetic-core current detection structure in claim 1; and performing residual current demodulation on a second harmonic component signal in the induced electromotive force signal to obtain a residual current signal in the line to be detected. According to the invention, accurate detection of the milliampere-level tiny residual current is realized under a large-current working condition through the double-magnetic-core current detection structure and the current detection method, and a milliampere-level direct-current residual current signal is modulated to a high-frequency carrier wave by using a magnetic modulation principle, so that the signal-to-noise ratio is remarkably improved, and the detection precision is improved. The problem of detecting tiny signals under the background of large signals is solved.

Description

Technical Field

[0001] The present application relates to the technical field of direct current systems, and in particular to a dual-core current detection structure and a current detection method. Background Art

[0002] With the rapid development of DC systems such as new energy and data centers, the demand for DC residual current protection in frame circuit breakers is increasing.

[0003] However, the existing AC residual current protection device has problems such as low detection accuracy and poor anti-interference ability when detecting DC residual current due to the use of a traditional zero-sequence mutual inductor structure. Summary of the Invention

[0004] Based on this, it is necessary to provide a dual-core current detection structure and current detection method that can accurately detect DC residual current to address the above technical problems.

[0005] The first magnetic core and the second magnetic core are respectively arranged around the circuit to be detected;

[0006] an excitation winding wound around the first magnetic core in a first direction and wound around the second magnetic core in a second direction; the first direction is opposite to the second direction;

[0007] an excitation source, connected in series to the excitation winding, for providing an AC excitation signal to the excitation winding;

[0008] a detection winding, wound around the first magnetic core and the second magnetic core respectively along a third direction;

[0009] a signal detector connected in series with the detection winding, for detecting a signal induced by the detection winding after the AC excitation signal is applied to the excitation winding, to obtain an induced electromotive force signal; the induced electromotive force signal is used to determine a residual current signal in the circuit to be detected;

[0010] The number of turns of the excitation winding on the first magnetic core is the same as the number of turns of the excitation winding on the second magnetic core; the number of turns of the detection winding on the first magnetic core is the same as the number of turns of the detection winding on the second magnetic core; the frequency of the AC excitation signal is 10 kHz, and the amplitude of the AC excitation signal is 2.5 volts.

[0011] In one embodiment, the excitation source includes an operational amplifier, a first resistor, a second resistor, and a third resistor;

[0012] The output terminal of the operational amplifier is connected to the first end of the first resistor, the non-inverting input terminal of the operational amplifier is connected to the second end of the first resistor, and the inverting input terminal of the operational amplifier is connected to the first end of the third resistor;

[0013] The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is grounded;

[0014] A first end of the third resistor is connected to the inverting input end of the operational amplifier, and a second end of the third resistor is grounded.

[0015] In a second aspect, the present application provides a current detection method. The method comprises:

[0016] collecting the induced electromotive force signal detected by the signal detector in the dual-core current detection structure according to claim 1;

[0017] The residual current demodulation is performed on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected.

[0018] In one embodiment, performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the line to be detected includes:

[0019] extracting a second harmonic component signal from the induced electromotive force signal;

[0020] performing a sliding mean filter on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal;

[0021] The residual current signal is determined according to the second harmonic component signal after filtering.

[0022] In one embodiment, determining the residual current signal based on the filtered second harmonic component signal includes:

[0023] The amplitude of the second harmonic component signal after filtering is demodulated to obtain the residual current signal.

[0024] In one embodiment, extracting the second harmonic component signal from the induced electromotive force signal includes:

[0025] A fourth-order Butterworth structure filter with a passband of a preset frequency range is used to perform bandpass filtering on the induced electromotive force signal to obtain a second harmonic component signal of a target frequency in the induced electromotive force signal.

[0026] In a third aspect, the present application further provides a current detection device. The device comprises:

[0027] an acquisition module for acquiring an induced electromotive force signal detected by a signal detector in the dual-core current detection structure according to claim 1;

[0028] The demodulation module is used to perform residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected.

[0029] In a fourth aspect, the present application further provides a computer device. The computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0030] collecting the induced electromotive force signal detected by the signal detector in the dual-core current detection structure according to claim 1;

[0031] The residual current demodulation is performed on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected.

[0032] In a fifth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the following steps:

[0033] collecting the induced electromotive force signal detected by the signal detector in the dual-core current detection structure according to claim 1;

[0034] The residual current demodulation is performed on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected.

[0035] In a sixth aspect, the present application further provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the following steps:

[0036] collecting the induced electromotive force signal detected by the signal detector in the dual-core current detection structure according to claim 1;

[0037] The residual current demodulation is performed on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected.

[0038] The above-mentioned dual-core current detection structure and current detection method, when there is a DC residual current in the circuit to be detected, pass an AC excitation signal into the excitation winding in the dual-core current detection structure to generate an induced electromotive force signal on the detection winding in the dual-core current detection structure; collect the induced electromotive force signal in the detection winding; perform residual current detection on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected. According to the above content, the present application realizes the accurate detection of tiny residual current in the milliampere level under large current conditions through the dual-core current detection structure and current detection method, and uses the magnetic modulation principle to modulate the DC residual current signal in the milliampere level onto a high-frequency carrier, significantly improving the signal-to-noise ratio and solving the problem of detecting tiny signals under large signal background; and by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal, effectively ensuring the detection accuracy of the residual current signal, realizing the low-cost dual-core current detection structure, effectively ensuring the DC residual current detection accuracy of the circuit to be detected, improving the cost-effectiveness of current detection, avoiding the cumbersome current detection process, and improving the detection efficiency of DC residual current. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic structural diagram of a dual-core current detection structure provided in an embodiment of the present application;

[0040] Figure 2 A diagram illustrating an application environment of a current detection method provided in an embodiment of the present application;

[0041] Figure 3 A schematic flow chart of a first current detection method provided in an embodiment of the present application;

[0042] Figure 4 A schematic flow chart of a second current detection method provided in an embodiment of the present application;

[0043] Figure 5 A schematic flow chart of a third current detection method provided in an embodiment of the present application;

[0044] Figure 6 A schematic diagram of a simulation module of a current detection method provided in an embodiment of the present application;

[0045] Figure 7 A schematic diagram of a current detection effect provided in an embodiment of the present application;

[0046] Figure 8 A structural block diagram of a current detection device provided in an embodiment of the present application;

[0047] Figure 9 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0049] It should be understood that the specific embodiments described herein are merely used to explain the present application and are not intended to limit the present application. In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they contradict each other.

[0050] With the rapid development of DC systems in new energy, data centers, and other areas, the demand for DC residual current protection in frame circuit breakers is growing. Existing AC residual current protection devices, due to their traditional zero-sequence transformer structure, suffer from low accuracy and poor interference immunity when detecting DC residual current. Especially under high current conditions exceeding 2000A, factors such as strong magnetic field interference in the main circuit, power frequency interference, and switching power supply noise seriously affect detection effectiveness.

[0051] In high-current frame circuit breaker systems, the main circuit operating current can reach 2000A, while the residual current signal to be detected is typically in the milliampere range, a difference of 3-4 orders of magnitude. The difficulty in detecting small signals against this large signal background is primarily reflected in the following aspects: First, the strong magnetic field generated by the large main circuit current can cause the detection element to saturate, rendering it unable to detect small signals; second, small fluctuations in the main circuit current can induce interference signals in the detection circuit equivalent to the residual current, causing misjudgment; third, power frequency interference and switching power supply noise in the system can bury the weak residual current signal, seriously affecting detection accuracy.

[0052] Currently, the two most commonly used methods for detecting DC residual current in the industry are Hall effect sensors and fluxgate sensors. The Hall effect sensor method is relatively expensive, exhibits significant temperature drift, and suffers from poor long-term stability. While the fluxgate sensor method offers high sensitivity, it is susceptible to interference from external magnetic fields and prone to magnetic saturation under high current conditions. Furthermore, these methods often require complex signal conditioning circuits and compensation algorithms in practical applications, increasing product cost and implementation complexity.

[0053] To address these issues, the industry urgently needs a DC residual current detection technology with high accuracy, strong anti-interference capabilities, simple structure, and reasonable cost to meet the current protection requirements of high-current frame circuit breakers. This is especially true in areas such as smart grids and renewable energy generation, which place higher demands on the reliability and stability of DC residual current protection in frame circuit breakers.

[0054] To this end, this application provides a dual-core current detection structure and method that effectively address issues such as strong magnetic field interference in the main circuit and system noise under high current conditions up to 2000A, enabling accurate detection of tiny residual currents in the milliampere range. This application aims to achieve the engineering advantages of simple structure and moderate cost, providing a reliable technical solution for DC residual current protection in frame circuit breakers.

[0055] In one embodiment, if Figure 1 As shown, the present application provides a dual-core current detection structure, which includes:

[0056] The first magnetic core and the second magnetic core are respectively arranged around the circuit to be detected;

[0057] an excitation winding wound on the first magnetic core along a first direction and wound on the second magnetic core along a second direction; the first direction is opposite to the second direction;

[0058] An excitation source is connected in series with the excitation winding and is used to provide an AC excitation signal to the excitation winding;

[0059] The detection winding is wound on the first magnetic core and the second magnetic core along the third direction respectively;

[0060] A signal detector is connected in series with the detection winding and is used to detect the signal induced by the detection winding after the AC excitation signal is applied to the excitation winding, thereby obtaining an induced electromotive force signal; the induced electromotive force signal is used to determine the residual current signal in the circuit to be detected;

[0061] The number of turns of the excitation winding on the first magnetic core is the same as the number of turns of the excitation winding on the second magnetic core; the number of turns of the detection winding on the first magnetic core is the same as the number of turns of the detection winding on the second magnetic core; the frequency of the AC excitation signal is 10 kHz, and the amplitude of the AC excitation signal is 2.5 volts.

[0062] It should be noted that the first magnetic core and the second magnetic core are two magnetic cores with exactly the same magnetic core length and magnetic core material.

[0063] Furthermore, the core materials of the first magnetic core and the second magnetic core can be set or adjusted according to actual conditions and actual needs. The core materials of the first magnetic core and the second magnetic core are not limited here. As an example: the core materials of the first magnetic core and the second magnetic core can be wound with iron-based nanocrystalline materials. The iron-based nanocrystalline materials have high saturation magnetic induction intensity, high magnetic permeability, low coercive force, and low loss; and the iron-based nanocrystalline materials have good temperature stability at -55 to 150°C and are soft magnetic materials with excellent performance.

[0064] Furthermore, the core sizes of the first magnetic core and the second magnetic core can be set or adjusted according to actual conditions. The core sizes of the first magnetic core and the second magnetic core are not limited here. As an example: the core sizes of the first magnetic core and the second magnetic core can be an inner diameter of 110 mm, an outer diameter of 130 mm, and a height of 35 mm.

[0065] In one embodiment of the present application, Figure 1 As shown, the excitation source includes an operational amplifier, a first resistor, a second resistor, and a third resistor;

[0066] The output terminal of the operational amplifier is connected to the first end of the first resistor, the non-inverting input terminal of the operational amplifier is connected to the second end of the first resistor, and the inverting input terminal of the operational amplifier is connected to the first end of the third resistor;

[0067] The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is grounded;

[0068] A first end of the third resistor is connected to the inverting input end of the operational amplifier, and a second end of the third resistor is grounded.

[0069] The above-mentioned dual-core current detection structure, when performing current detection through the dual-core current detection structure, can, in the case where there is a DC residual current in the circuit to be detected, introduce an AC excitation signal into the excitation winding in the dual-core current detection structure to generate an induced electromotive force signal on the detection winding in the dual-core current detection structure; collect the induced electromotive force signal in the detection winding; perform residual current detection on the second harmonic component signal in the induced electromotive force signal, and obtain the residual current signal in the circuit to be detected. According to the above content, the present application realizes the accurate detection of tiny residual current in the milliampere level under high current conditions through a dual-core current detection structure and a current detection method, and uses the magnetic modulation principle to modulate the DC residual current signal in the milliampere level onto a high-frequency carrier, which significantly improves the signal-to-noise ratio and solves the problem of detecting tiny signals under a large signal background; and, by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal, the detection accuracy of the residual current signal is effectively guaranteed, and the low-cost dual-core current detection structure is used to effectively ensure the DC residual current detection accuracy of the circuit to be detected, thereby improving the cost-effectiveness of current detection, avoiding the cumbersome current detection process, and improving the detection efficiency of DC residual current.

[0070] The current detection method provided in the embodiment of the present application can be applied to Figure 2 In the application environment shown. The terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be integrated on the server 104, or it can be placed on the cloud or other network servers. Collect the induced electromotive force signal detected by the signal detector in the dual-core current detection structure of claim 1; perform residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the line to be detected. The terminal 102 can be, but is not limited to, various personal computers, laptops, smart phones, tablets, Internet of Things devices and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart car-mounted devices, etc. Portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server 104 can be implemented as an independent server or a server cluster consisting of multiple servers.

[0071] In one embodiment, Figure 3 As shown, a current detection method is provided, which is applied to Figure 1 Taking the server 104 in the example as an example, the following steps are included:

[0072] S301 , collecting an induced electromotive force signal detected by a signal detector in the dual-core current detection structure of claim 1 .

[0073] It should be noted that when a DC residual current exists in the circuit to be tested, an AC excitation signal is input to the excitation winding via an excitation source, generating an alternating magnetic field. The AC excitation signal has a frequency of 10 kHz and an amplitude of 2.5 volts. The DC magnetic field of the circuit to be tested is applied to the first and second cores, which modulate the magnetic field distribution of the main core through magnetic coupling. The detection winding then generates an induced electromotive force signal, which contains a fundamental frequency component (10 kHz) and a second harmonic component (20 kHz), the amplitude of which is linearly correlated with the DC residual current.

[0074] S302 , performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain a residual current signal in the line to be detected.

[0075] It should be noted that, since the second harmonic component signal in the induced electromotive force signal is linearly correlated with the DC residual current, the residual current signal in the line to be detected can be obtained by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal.

[0076] After obtaining the residual current signal, the magnitude relationship between the residual current signal and the preset threshold can be detected. If the residual current is greater than the preset threshold, the drive alarm is triggered to remind the user to pay attention to electrical safety.

[0077] The above-mentioned current detection method, when there is a DC residual current in the circuit to be detected, passes an AC excitation signal into the excitation winding in the dual-core current detection structure, so that an induced electromotive force signal is generated on the detection winding in the dual-core current detection structure; collects the induced electromotive force signal in the detection winding; performs residual current detection on the second harmonic component signal in the induced electromotive force signal, and obtains the residual current signal in the circuit to be detected. According to the above content, the present application realizes the accurate detection of tiny residual current in the milliampere level under large current conditions through the dual-core current detection structure and the current detection method, and uses the magnetic modulation principle to modulate the DC residual current signal in the milliampere level onto a high-frequency carrier, which significantly improves the signal-to-noise ratio and solves the problem of detecting tiny signals under large signal background; and by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal, the detection accuracy of the residual current signal is effectively guaranteed, and the low-cost dual-core current detection structure is used to effectively ensure the DC residual current detection accuracy of the circuit to be detected, improve the cost-effectiveness of current detection, avoid the cumbersome current detection process, and improve the detection efficiency of DC residual current.

[0078] In one embodiment, if Figure 4As shown, when it is necessary to perform residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the line to be detected, the following contents may be included:

[0079] S401, extracting the second harmonic component signal from the induced electromotive force signal.

[0080] It should be noted that when it is necessary to extract the second harmonic component signal from the induced electromotive force signal, a fourth-order Butterworth structure filter with a passband of a preset frequency range can be used to bandpass filter the induced electromotive force signal to obtain the second harmonic component signal of the target frequency in the induced electromotive force signal.

[0081] Here, since the frequency of the AC excitation signal is 10 kHz and the amplitude of the AC excitation signal is 2.5 V, the preset frequency range is 19-21 kHz; and the target frequency is 20 kHz.

[0082] To further illustrate, before extracting the second harmonic component signal from the induced electromotive force signal, the induced electromotive force signal may be first filtered and amplified based on a filtering and amplifying circuit to ensure that the induced electromotive force signal can be more convenient for subsequent related signal operations.

[0083] Since the second harmonic component signal needs to be subjected to sliding mean filtering processing later, the induced electromotive force signal needs to be converted from an analog signal to a digital signal through the CPU.

[0084] S402 , performing sliding mean filtering on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal.

[0085] The preset signal length can be set or adjusted according to actual conditions, and the preset signal length is not limited here; as an example, the preset signal length can be 50.

[0086] It should be noted that the sliding average filter is mainly used in the dual-core magnetic modulation detection system corresponding to the dual-core current detection structure to suppress the residual noise in the second harmonic signal after bandpass filtering while maintaining the dynamic response characteristics of the signal. Its mechanism of action can be decomposed into the following dimensions:

[0087] (1) Noise suppression and signal-to-noise ratio improvement:

[0088] 1. Random noise smoothing;

[0089] Even after bandpass filtering (19-21 kHz), the second harmonic component still contains high-frequency random noise. A sliding average filter calculates the arithmetic mean of 50 consecutive sampling points (the default signal length is 50), distributing the noise energy over multiple sampling periods and significantly reducing the signal's fluctuation amplitude. For example, when the noise standard deviation is σ, N-point filtering can reduce the noise amplitude to σ / √N (approximately 7x noise reduction when N = 50).

[0090] 2. Power frequency interference suppression;

[0091] Under high-current conditions on the line under test, 50 / 60Hz power-frequency magnetic fields can generate low-frequency modulation interference through magnetic coupling. The sliding mean filter window, with a preset signal length of N = 50 (corresponding to a 5ms update time), covers multiple power-frequency cycles, offsetting the cumulative effect of periodic interference through averaging.

[0092] (2) Signal fidelity and demodulation preparation:

[0093] 1. Phase holding characteristics;

[0094] As a linear phase filter, the sliding average filter does not introduce additional phase offset, ensuring the accuracy of the amplitude demodulation of the second harmonic component signal during subsequent envelope detection.

[0095] 2. Enhanced amplitude stability;

[0096] After filtering, the amplitude fluctuation of the second harmonic component signal is limited to ±2%, avoiding false triggering due to noise and meeting the requirements of milliampere-level residual current detection.

[0097] In one embodiment of the present application, the sliding average filtering algorithm may be as follows:

[0098]

[0099] Where x is the input data, y is the smoothed output data, n is the number of data points, i is the data sequence number, and j is the loop sequence number, ranging from 0 to n-1. Specifically, a data buffer is established in the sliding average filter algorithm to store n second harmonic component signals. Each time a new second harmonic component signal is sampled, the oldest second harmonic component signal collected in the data buffer is deleted. The arithmetic mean of the data is then calculated using the sliding average filter algorithm.

[0100] S403: Determine a residual current signal according to the filtered second harmonic component signal.

[0101] It should be noted that when it is necessary to determine the residual current signal based on the filtered second harmonic component signal, the filtered second harmonic component signal may be amplitude demodulated to obtain the residual current signal.

[0102] In one embodiment of the present application, the method of performing amplitude demodulation on the second harmonic component signal after filtering may include: envelope detection method, synchronous demodulation method and phase-sensitive detection method, etc. In summary, there are many methods of amplitude demodulation, and the method of performing amplitude demodulation on the second harmonic component signal after filtering is not limited here.

[0103] In one embodiment of the present application, when it is necessary to determine the residual current signal, the following contents may be included: an A / D converter with a sampling frequency of 100kHz is used to sample the detection winding, and the data resolution is 16 bits. The sampled induced electromotive force signal is band-pass filtered to extract the second harmonic component signal of 20kHz. This band-pass filter adopts a 4th-order Butterworth structure with a passband of 19-21kHz, which can effectively suppress interference from other frequencies. The second harmonic component signal is further processed using a sliding mean filter with a length of N=50 points. This filter window is updated every 5ms, which can suppress power frequency interference and high-frequency noise in real time. After the filtered signal is processed, the residual current value is obtained by amplitude demodulation. The demodulation is implemented using envelope detection, which can accurately extract the residual current information.

[0104] The above-mentioned current detection method obtains the residual current signal in the circuit to be detected by performing residual current detection on the second harmonic component signal in the induced electromotive force signal; it realizes the low-cost dual-core current detection structure, effectively ensures the accuracy of DC residual current detection in the circuit to be detected, improves the cost-effectiveness of current detection, avoids the cumbersome current detection process, and improves the detection efficiency of DC residual current.

[0105] In one embodiment, if Figure 5 As shown, when it is necessary to obtain the residual current signal in the line to be detected, the following contents may be included:

[0106] S501 , collecting an induced electromotive force signal detected by a signal detector in the dual-core current detection structure of claim 1 .

[0107] S502, filtering and amplifying the induced electromotive force signal through a filtering and amplifying circuit.

[0108] S503: Convert the induced electromotive force signal from an analog signal to a digital signal through the CPU.

[0109] S504 , using a fourth-order Butterworth structure filter with a passband of a preset frequency range to perform bandpass filtering on the induced electromotive force signal to obtain a second harmonic component signal of a target frequency in the induced electromotive force signal.

[0110] S505 , performing sliding mean filtering on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal.

[0111] S506 , performing amplitude demodulation on the filtered second harmonic component signal to obtain a residual current signal.

[0112] S507, determining the magnitude relationship between the residual current signal and a preset threshold value, and triggering a driving alarm if the residual current is greater than the preset threshold value.

[0113] In one embodiment of the present application, the dual-core current detection structure and the current detection method can construct a dual-core modulation mutual inductor simulation model. The dual-core modulation mutual inductor simulation model is as follows: Figure 6 As shown, it includes a modulation module and a demodulation module; the modulation module includes: an excitation voltage module, a sampling module, a residual current generation module, a mutual inductor module 1 and a mutual inductor module 2; wherein, the residual current generation module is used to simulate the occurrence of residual current, the mutual inductor module 1 and the mutual inductor module 2 simulate the excitation winding and the detection winding, the sampling module is used to sense the generated signal for detection, and the demodulation module is used to perform residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the line to be detected; further, the dual-core magnetic modulation simulation results are shown as follows Figure 7 shown.

[0114] The above-mentioned current detection method, when there is a DC residual current in the circuit to be detected, passes an AC excitation signal into the excitation winding in the dual-core current detection structure, so that an induced electromotive force signal is generated on the detection winding in the dual-core current detection structure; collects the induced electromotive force signal in the detection winding; performs residual current detection on the second harmonic component signal in the induced electromotive force signal, and obtains the residual current signal in the circuit to be detected. According to the above content, the present application realizes the accurate detection of tiny residual current in the milliampere level under large current conditions through the dual-core current detection structure and the current detection method, and uses the magnetic modulation principle to modulate the DC residual current signal in the milliampere level onto a high-frequency carrier, which significantly improves the signal-to-noise ratio and solves the problem of detecting tiny signals under large signal background; and by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal, the detection accuracy of the residual current signal is effectively guaranteed, and the low-cost dual-core current detection structure is used to effectively ensure the DC residual current detection accuracy of the circuit to be detected, improve the cost-effectiveness of current detection, avoid the cumbersome current detection process, and improve the detection efficiency of DC residual current.

[0115] It should be understood that, although the steps in the flowcharts of the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts of the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily to be performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0116] Based on the same inventive concept, the present application also provides a current detection device for implementing the current detection method described above. The solution provided by this device is similar to the solution described in the method described above. Therefore, the specific limitations of one or more current detection device embodiments provided below can be found in the above-mentioned limitations of the current detection method and will not be repeated here.

[0117] In one embodiment, Figure 8 As shown, a current detection device is provided, including: an acquisition module 10 and a demodulation module 20, wherein:

[0118] The acquisition module 10 is used to acquire the induced electromotive force signal detected by the signal detector in the dual-core current detection structure of claim 1.

[0119] The demodulation module 20 is used to perform residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain a residual current signal in the line to be detected.

[0120] In one embodiment, extracting a second harmonic component signal from the induced electromotive force signal;

[0121] Performing a sliding mean filter on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal;

[0122] The residual current signal is determined according to the second harmonic component signal after filtering.

[0123] In one embodiment, amplitude demodulation is performed on the filtered second harmonic component signal to obtain a residual current signal.

[0124] In one embodiment, a fourth-order Butterworth structure filter with a passband of a preset frequency range is used to perform bandpass filtering on the induced electromotive force signal to obtain a second harmonic component signal of a target frequency in the induced electromotive force signal.

[0125] The above-mentioned current detection device, when there is a DC residual current in the circuit to be detected, passes an AC excitation signal into the excitation winding in the dual-core current detection structure, so that an induced electromotive force signal is generated on the detection winding in the dual-core current detection structure; collects the induced electromotive force signal in the detection winding; performs residual current detection on the second harmonic component signal in the induced electromotive force signal, and obtains the residual current signal in the circuit to be detected. According to the above content, the present application realizes the accurate detection of tiny residual current in the milliampere level under large current conditions through the dual-core current detection structure and the current detection method, and uses the magnetic modulation principle to modulate the DC residual current signal in the milliampere level onto a high-frequency carrier, significantly improving the signal-to-noise ratio and solving the problem of detecting tiny signals under large signal background; and by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal, effectively ensuring the detection accuracy of the residual current signal, realizing the low-cost dual-core current detection structure, effectively ensuring the DC residual current detection accuracy of the circuit to be detected, improving the cost-effectiveness of current detection, avoiding the cumbersome current detection process, and improving the detection efficiency of DC residual current.

[0126] Each module in the above-mentioned current detection device can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0127] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 9As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface, the display unit and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a current detection method is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device casing, or an external keyboard, touchpad or mouse.

[0128] Those skilled in the art will understand that Figure 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0129] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0130] collecting an induced electromotive force signal detected by a signal detector in the dual-core current detection structure of claim 1;

[0131] The residual current signal in the line to be detected is obtained by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal.

[0132] Extract the second harmonic component signal from the induced electromotive force signal;

[0133] Performing a sliding mean filter on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal;

[0134] The residual current signal is determined according to the second harmonic component signal after filtering.

[0135] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0136] The amplitude of the second harmonic component signal after filtering is demodulated to obtain the residual current signal.

[0137] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0138] A fourth-order Butterworth structure filter with a passband of a preset frequency range is used to bandpass filter the induced electromotive force signal to obtain the second harmonic component signal of the target frequency in the induced electromotive force signal.

[0139] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0140] collecting an induced electromotive force signal detected by a signal detector in the dual-core current detection structure of claim 1;

[0141] The residual current signal in the line to be detected is obtained by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal.

[0142] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0143] Extract the second harmonic component signal from the induced electromotive force signal;

[0144] Performing a sliding mean filter on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal;

[0145] The residual current signal is determined according to the second harmonic component signal after filtering.

[0146] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0147] The amplitude of the second harmonic component signal after filtering is demodulated to obtain the residual current signal.

[0148] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0149] A fourth-order Butterworth structure filter with a passband of a preset frequency range is used to bandpass filter the induced electromotive force signal to obtain the second harmonic component signal of the target frequency in the induced electromotive force signal.

[0150] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0151] collecting an induced electromotive force signal detected by a signal detector in the dual-core current detection structure of claim 1;

[0152] The residual current signal in the line to be detected is obtained by performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal.

[0153] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0154] Extract the second harmonic component signal from the induced electromotive force signal;

[0155] Performing a sliding mean filter on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal;

[0156] The residual current signal is determined according to the second harmonic component signal after filtering.

[0157] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0158] The amplitude of the second harmonic component signal after filtering is demodulated to obtain the residual current signal.

[0159] In one embodiment, when the computer program is executed by a processor, the following steps are further implemented:

[0160] A fourth-order Butterworth structure filter with a passband of a preset frequency range is used to bandpass filter the induced electromotive force signal to obtain the second harmonic component signal of the target frequency in the induced electromotive force signal.

[0161] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions.

[0162] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, and the like.

[0163] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0164] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A dual-core current detection structure, characterized in that: The structure includes: The first magnetic core and the second magnetic core are respectively arranged around the circuit to be detected; an excitation winding wound around the first magnetic core in a first direction and wound around the second magnetic core in a second direction; the first direction is opposite to the second direction; an excitation source, connected in series to the excitation winding, for providing an AC excitation signal to the excitation winding; a detection winding, wound around the first magnetic core and the second magnetic core respectively along a third direction; a signal detector connected in series with the detection winding, for detecting a signal induced by the detection winding after the AC excitation signal is applied to the excitation winding, to obtain an induced electromotive force signal; the induced electromotive force signal is used to determine a residual current signal in the circuit to be detected; The number of turns of the excitation winding on the first magnetic core is the same as the number of turns of the excitation winding on the second magnetic core; the number of turns of the detection winding on the first magnetic core is the same as the number of turns of the detection winding on the second magnetic core; the frequency of the AC excitation signal is 10 kHz, and the amplitude of the AC excitation signal is 2.5 volts.

2. The structure according to claim 1, characterized in that The excitation source includes an operational amplifier, a first resistor, a second resistor and a third resistor; The output terminal of the operational amplifier is connected to the first end of the first resistor, the non-inverting input terminal of the operational amplifier is connected to the second end of the first resistor, and the inverting input terminal of the operational amplifier is connected to the first end of the third resistor; The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is grounded; A first end of the third resistor is connected to the inverting input end of the operational amplifier, and a second end of the third resistor is grounded.

3. A current detection method, characterized in that: The method comprises: collecting the induced electromotive force signal detected by the signal detector in the dual-core current detection structure according to claim 1; The residual current demodulation is performed on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected.

4. The method according to claim 3, characterized in that The performing residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the line to be detected includes: extracting a second harmonic component signal from the induced electromotive force signal; performing a sliding mean filter on the second harmonic component signal based on a preset signal length to obtain a filtered second harmonic component signal; The residual current signal is determined according to the second harmonic component signal after filtering.

5. The method according to claim 4, characterized in that The determining of the residual current signal according to the filtered second harmonic component signal includes: The amplitude of the second harmonic component signal after filtering is demodulated to obtain the residual current signal.

6. The method according to claim 4, characterized in that The extracting of the second harmonic component signal from the induced electromotive force signal comprises: A fourth-order Butterworth structure filter with a passband of a preset frequency range is used to perform bandpass filtering on the induced electromotive force signal to obtain a second harmonic component signal of a target frequency in the induced electromotive force signal.

7. A current detection device, characterized in that: The device comprises: an acquisition module for acquiring an induced electromotive force signal detected by a signal detector in the dual-core current detection structure according to claim 1; The demodulation module is used to perform residual current demodulation on the second harmonic component signal in the induced electromotive force signal to obtain the residual current signal in the circuit to be detected.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 2 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 2 to 6 are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 2 to 6 are implemented.

Images