fluxgate circuit

Abstract

The application relates to a fluxgate circuit which comprises a controller, an excitation source, a sensing assembly, a feedback loop and a signal processing assembly; wherein the controller is connected to the control end of the excitation source, the control end of the feedback loop and the control end of the signal processing assembly respectively; the output end of the feedback loop and the output end of the signal processing assembly are both connected to the input end of the excitation source; the controller is used for controlling the excitation source to generate an excitation signal, and adjusting the excitation source according to a feedback signal output by the feedback loop when the excitation signal is a low-frequency signal, and adjusting the excitation source according to a signal output by the signal processing assembly when the excitation signal is a high-frequency signal. The above fluxgate circuit can effectively reduce external interference and measurement error, improve the measurement precision, eliminate interference and noise in the circuit through the signal processing assembly, eliminate high-frequency interference and noise, and ensure the reliability of the signal.

Description

Technical Field

[0001] The present application relates to the field of fluxgate technology, and in particular to a fluxgate circuit. Background Art

[0002] The operating principle of a fluxgate sensor is based on the magnetic saturation characteristics of nonlinear core materials (such as Permalloy, amorphous, and nanocrystalline materials) in the presence of an alternating magnetic field. When the magnetic field being measured acts on the core, it causes a change in the magnetic flux within the core, which in turn generates an induced electromotive force (EMF) through the coil wound around the core. Because the induced EMF is related to the magnitude and direction of the measured magnetic field, it can be used to measure the magnetic field.

[0003] However, the fluxgate sensor in the related art is susceptible to environmental interference during the process of measuring the magnetic field, and has the problem of low measurement accuracy. Summary of the Invention

[0004] Based on this, it is necessary to provide a fluxgate circuit that can improve measurement accuracy in response to the above technical problems.

[0005] In a first aspect, the present application provides a fluxgate circuit, the fluxgate circuit comprising: a controller, an excitation source, a sensing component, a feedback loop, and a signal processing component;

[0006] The controller is connected to the control end of the excitation source, the control end of the feedback loop and the control end of the signal processing component respectively; the output end of the feedback loop and the output end of the signal processing component are both connected to the input end of the excitation source;

[0007] The controller is used to control the excitation source to generate an excitation signal, and to adjust the excitation source according to the feedback signal output by the feedback loop when the excitation signal is a low-frequency signal, and to adjust the excitation source according to the signal output by the signal processing component when the excitation signal is a high-frequency signal.

[0008] In one embodiment, the fluxgate circuit includes: a low-frequency fluxgate circuit and a high-frequency fluxgate circuit;

[0009] The low-frequency fluxgate circuit includes: a first excitation source among the excitation sources, a first sensing component among the sensing components, and a feedback loop; the feedback loop is used to determine a feedback signal based on a first target signal and a first expected signal output by the first sensing component, and to adjust the excitation signal output by the first excitation source based on the feedback signal;

[0010] The high-frequency fluxgate circuit includes: a second excitation source in the excitation source, a second sensing component in the sensing component, and a signal processing component; the signal processing component is used to adjust the frequency and gain of the excitation signal output by the second excitation source according to the relationship between the output signal and the input signal of the second sensing component.

[0011] In one embodiment, the feedback loop includes: a comparator connected to the first sensing component and the controller;

[0012] The comparator is used to compare the first target signal with the first expected signal to obtain a comparison result;

[0013] The controller is used to determine a feedback signal according to the comparison result.

[0014] In one embodiment, the feedback loop further includes: a gain adjuster; the gain adjuster is connected to the output end of the controller and the input end of the first excitation source;

[0015] The controller is used to control the gain adjuster to adjust the gain of the excitation signal output by the first excitation source.

[0016] In one embodiment, the first sensing assembly includes a first sensor and a first excitation winding, wherein the input end of the first sensor is connected to the first excitation source, the output end of the first sensor is connected to the input end of the first excitation winding, and the output end of the first excitation winding is connected to the feedback loop;

[0017] The first sensor is used to detect the first excitation signal;

[0018] The first excitation winding is used to generate a first target signal according to a first excitation signal.

[0019] In one embodiment, the first excitation winding includes a first magnetic core; the material of the first magnetic core is a soft magnetic material with high magnetic permeability, and the material of the first magnetic core includes ferrite or silicon steel sheet.

[0020] In one embodiment, the low-frequency fluxgate circuit further includes: a filter component; the filter component is respectively arranged between the first excitation source and the first sensing component and between the first sensing component and the feedback loop.

[0021] In one embodiment, the signal processing component includes: an amplifier and a filter;

[0022] The input end of the amplifier is connected to the output end of the second sensor component, the output end of the amplifier is connected to the input end of the filter, and the output end of the filter is connected to the controller;

[0023] The amplifier is used to amplify the output signal of the second sensor component to obtain an amplified output signal;

[0024] The filter is used to filter the amplified signal to obtain a filtered output signal;

[0025] The controller is used to adjust the frequency and gain of the excitation signal output by the second excitation source according to the relationship between the filtered output signal and the input signal.

[0026] In one of the embodiments, the second sensing assembly comprises a second sensor and a second excitation winding, an input end of the second sensor is connected with the second excitation source, an output end of the second sensor is connected with an input end of the second excitation winding, and an output end of the second excitation winding is connected with the amplifier;

[0027] The second sensor is used for detecting the second excitation signal.

[0028] The second excitation winding is used for generating the second target signal according to the second excitation signal.

[0029] In one of the embodiments, the second excitation winding comprises a second magnetic core; the material of the second magnetic core is a low-loss soft magnetic material, and the material of the second magnetic core comprises iron-nickel alloy; and the structure of the second magnetic core is a ring structure or an E-shaped structure.

[0030] The above-mentioned fluxgate circuit comprises a controller, an excitation source, a sensing assembly, a feedback loop and a signal processing assembly; wherein the controller is connected with a control end of the excitation source, a control end of the feedback loop and a control end of the signal processing assembly respectively; an output end of the feedback loop and an output end of the signal processing assembly are both connected with an input end of the excitation source; and the controller is used for controlling the excitation source to generate an excitation signal, and adjusting the excitation source according to a feedback signal output by the feedback loop when the excitation signal is a low-frequency signal, and adjusting the excitation source according to a signal output by the signal processing assembly when the excitation signal is a high-frequency signal. The above-mentioned fluxgate circuit can effectively reduce external interference and measurement error, and improve the measurement precision by adjusting the excitation source according to the feedback signal output by the feedback loop, and can eliminate interference and noise in the circuit, eliminate high-frequency interference and noise, and ensure the reliability of the signal by the signal processing assembly. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the fluxgate circuit in one of the embodiments;

[0032] Figure 2 It is a structural schematic diagram of the low-frequency fluxgate circuit in one of the embodiments;

[0033] Figure 3 It is a structural schematic diagram of the high-frequency fluxgate circuit in one of the embodiments;

[0034] Figure 4 It is a structural schematic diagram of the low-frequency fluxgate circuit in another of the embodiments;

[0035] Explanation of the reference numerals: controller 10; excitation source 20; sensing component 30; feedback loop 40; signal processing component 50; first excitation source 201; first sensing component 301; first sensor 3011; first excitation winding 3012; second excitation source 202; second sensing component 302; amplifier 501 and filter 502; second sensor 3021; ​​second excitation winding 3022; comparator 401; gain adjuster 402; filtering component 404. DETAILED DESCRIPTION

[0036] 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.

[0037] The operating principle of a fluxgate sensor is based on the magnetic saturation characteristics of nonlinear core materials (such as Permalloy, amorphous, and nanocrystalline materials) in the presence of an alternating magnetic field. When the magnetic field to be measured acts on the core, it causes a change in the magnetic flux within the core, which in turn generates an induced electromotive force (EMF) through the coil wound around the core. Since the induced EMF is related to the magnitude and direction of the measured magnetic field, it can be used to measure the magnetic field. However, fluxgate sensors in related technologies are susceptible to environmental interference during magnetic field measurement, resulting in low measurement accuracy.

[0038] The present application provides a fluxgate circuit, aiming to solve the above-mentioned technical problems. The following embodiments will specifically illustrate the fluxgate circuit described in the present application.

[0039] In one embodiment, Figure 1 As shown, a fluxgate circuit is provided, which includes: a controller 10, an excitation source 20, a sensing component 30, a feedback loop 40 and a signal processing component 50;

[0040] Among them, the controller 10 is respectively connected to the control end of the excitation source 20, the control end of the feedback loop 40 and the control end of the signal processing component 50; the output end of the feedback loop 40 and the output end of the signal processing component 50 are both connected to the input end of the excitation source 20.

[0041] The controller 10 is configured to control the excitation source 20 to generate an excitation signal, and adjust the excitation source 20 according to a feedback signal output by the feedback loop 40 when the excitation signal is a low-frequency signal, and adjust the excitation source 20 according to a signal output by the signal processing component 50 when the excitation signal is a high-frequency signal. The excitation source 20 is configured to generate the excitation signal, and the excitation source 20 can be a current source, a voltage source, an oscillator, a signal generator, or the like. Specifically, according to the frequency of the generated excitation signal, the excitation source 20 can be classified into a first excitation source 201 and a second excitation source 202 according to the generation, the first excitation source 201 is configured to generate a low-frequency excitation signal, and the second excitation source 202 is configured to generate a high-frequency excitation signal. The sensing component 30 is configured to receive the excitation signal generated by the excitation source 20, and generate a target signal according to the excitation signal. The feedback loop 40 is configured to determine a feedback signal according to the first target signal and a first standard signal. The signal processing component 50 is configured to perform enhancement processing on the target signal output by the sensing component 30. The excitation signal can be a current signal or a voltage signal. The feedback signal can be an error signal between the first target signal and the first standard signal. The first target signal is a current signal or a voltage signal, and the type of the first target signal corresponds to the type of the excitation signal. The first standard signal is a current signal or a voltage signal, and the type of the first standard signal corresponds to the type of the excitation signal, and the first standard signal is determined according to actual requirements, and specifically can be determined according to actual measurement accuracy.

[0042] The magnetic flux gate circuit provided by the embodiment of the present application comprises a controller, an excitation source, a sensing component, a feedback loop, and a signal processing component. The controller is connected to the excitation source, the feedback loop, and the signal processing component. The excitation source is connected to the feedback loop and the signal processing component. The controller is configured to control the excitation source to generate an excitation signal, and adjust the excitation source according to a feedback signal output by the feedback loop, and adjust the excitation source according to a target signal output by the signal processing component. The magnetic flux gate circuit can effectively reduce external interference and measurement error, improve measurement accuracy, eliminate interference and noise in the circuit through the signal processing component, eliminate high-frequency interference and noise, and ensure signal reliability.

[0043] In one embodiment, the magnetic flux gate circuit comprises a low-frequency magnetic flux gate circuit and a high-frequency magnetic flux gate circuit.

[0044] In one embodiment, the magnetic flux gate circuit comprises a low-frequency magnetic flux gate circuit and a high-frequency magnetic flux gate circuit. Figure 2As shown, the low-frequency fluxgate circuit includes: a first excitation source 201 in the excitation source 20, a first sensing component 301 in the sensing component 30, and a feedback loop 40; the feedback loop 40 is used to determine a feedback signal according to a first target signal output by the first sensing component 301 and a first expected signal, and adjust an excitation signal output by the first excitation source 201 according to the feedback signal. The above-mentioned first sensing component 301 includes a first sensor 3011 and a first excitation winding 3012, the input end of the first sensor 3011 is connected with the first excitation source 201, the output end of the first sensor 3011 is connected with the input end of the first excitation winding 3012, and the output end of the first excitation winding 3012 is connected with the feedback loop 40. The above-mentioned first sensor 3011 is used to detect the first excitation signal. The above-mentioned first excitation winding 3012 is used to generate the first target signal according to the first excitation signal. The above-mentioned first excitation winding 3012 includes a first magnetic core; the material of the first magnetic core is a soft magnetic material with high magnetic permeability, and the material of the first magnetic core includes ferrite or silicon steel sheet, so as to ensure that it has low loss at low frequency. The shape of the first magnetic core is designed according to the principle of optimizing the number of turns and the layout of the winding, reducing the magnetic leakage and hysteresis loss.

[0045] The above-mentioned low-frequency fluxgate circuit can adopt the zero flux principle, design a closed-loop system to realize the precise measurement of direct current, and can be designed as a three-magnetic-core four-winding structure, one of which is used for detecting the average current (direct current zero flux detection), and the other two are used for suppressing the induced modulation ripple caused by the transformer effect (alternating current zero flux detection). In the closed-loop system, the excitation current is adjusted through the negative feedback mechanism to keep the magnetic flux in the magnetic core to zero, so as to realize the high-precision measurement of the measured current.

[0046] The above-mentioned low-frequency fluxgate circuit can introduce a digital circuit method to simplify the traditional analog signal processing module. For example, a digital signal processor (DSP) or a microcontroller (MCU) is used to realize the generation of the excitation signal, the collection and processing of the detection signal, and other functions. Through theoretical analysis of the relationship between the duty cycle of the excitation signal and the amplitude of the measured current, the digital sensing precision is improved. At the same time, based on this structure, the design and optimization of the negative feedback controller are carried out to ensure the stability and accuracy of the closed-loop system. At the same time, through reasonable layout and wiring design, signal interference and power consumption of the circuit are reduced. The above-mentioned low-frequency fluxgate circuit can follow the design principles of high-density interconnection PCB technology, and integrate more signal lines, components and interconnection methods into limited space. Through optimizing the wiring mode and using high-frequency materials to improve the signal transmission speed, the increasing data transmission demand is met. The device selection and manufacturing process are considered to realize the high-integration miniaturization of PCB plate making to adapt to the deployment requirements in the power environment.

[0047] In the embodiment of the present application, the working principle of the low-frequency fluxgate circuit is as follows: the controller 10 controls the first excitation source 201 to generate a first excitation signal, and then inputs the first excitation signal to the first sensor 3011. After the first sensor 3011 detects the first excitation signal, the first excitation signal can be transmitted to the first excitation winding 3012. After the first excitation winding 3012 receives the first excitation signal, it can generate a flux signal proportional to the first excitation signal, and then generate a first target signal according to the flux signal, and transmit the first target signal to the feedback loop 40. After the feedback loop 40 receives the first target signal, it can determine the feedback signal according to the first target signal and the first standard signal, and then return the feedback signal to the controller 10. After receiving the feedback signal, the controller 10 can adjust the excitation signal output by the first excitation source 201 according to the feedback signal, and repeat the cycle until the first target signal is consistent with the first standard signal, for example, the first target signal meets the threshold requirement of the first standard signal. Optionally, the error between the first target signal and the first standard signal converges.

[0048] The low-frequency fluxgate circuit also includes a filter component 404, which is disposed between the first excitation source 201 and the first sensor component 301, and between the first sensor component 301 and the feedback loop 40. Specifically, an effective filter circuit can be designed to eliminate the impact of high-frequency interference and noise on sensor performance. This includes the design of input and output filters 502, as well as filtering of the power supply circuit. Electromagnetic optimization is employed to prevent high-frequency signals from interfering with the normal operation of the sensor.

[0049] Among them, such as Figure 3 As shown, the high-frequency fluxgate circuit includes: a second excitation source 202 in the excitation source 20, a second sensing component 302 in the sensing component 30, and a signal processing component 50; the signal processing component 50 is used to adjust the frequency and gain of the excitation signal output by the second excitation source 202 according to the relationship between the output signal and the input signal of the second sensing component 302.

[0050] The signal processing assembly 50 comprises an amplifier 501 and a filter 502. The input end of the amplifier 501 is connected to the output end of the second sensing assembly 302, the output end of the amplifier 501 is connected to the input end of the filter 502, and the output end of the filter 502 is connected to the controller 10. The amplifier 501 is used to amplify the output signal of the second sensing assembly 302, obtain an amplified output signal, enhance the signal strength, and improve the anti-interference ability. The filter 502 is used to filter the amplified signal, obtain a filtered output signal, filter the noise, and improve the signal quality, so as to improve the signal quality and ensure the stability at high frequency. The controller 10 is used to adjust the frequency and gain of the excitation signal output by the second excitation source 202 according to the relationship between the filtered output signal and the input signal. The second sensing assembly 302 comprises a second sensor 3021 and a second excitation winding 3022. The input end of the second sensor 3021 is connected to the second excitation source 202, the output end of the second sensor 3021 is connected to the input end of the second excitation winding 3022, and the output end of the second excitation winding 3022 is connected to the amplifier 501. The second sensor 3021 is used to detect the second excitation signal. The second excitation winding 3022 is used to generate a second target signal according to the second excitation signal. The second excitation winding 3022 comprises a second magnetic core. The material of the second magnetic core is a low-loss soft magnetic material, and the material of the second magnetic core comprises iron-nickel alloy, so as to ensure good performance at high frequency. The structure of the second magnetic core is a ring structure or an E-shaped structure, so as to improve the induction sensitivity. The input signal of the second sensing assembly 302 is the second excitation signal, and the output signal of the second sensing assembly 302 is the second target signal. The second excitation source 202 is a high-frequency oscillator (such as a crystal oscillator), so as to provide a stable excitation signal and ensure the adjustability of the frequency. In a high-frequency open-loop system, the generation and detection of the excitation signal are critical. A suitable excitation circuit and detection circuit are designed to realize fast response and high-precision measurement of the measured current. Considering the characteristics of high-frequency signals, a differential amplification circuit, a high-speed comparator 401, and the like may be used to extract the detection signal and perform appropriate processing and amplification on the detection signal. A simple circuit topology is designed to avoid a complex feedback network and ensure fast response.

[0051] In the embodiment of the present application, the working principle of the high-frequency fluxgate circuit is as follows: the controller 10 controls the first excitation source 201 to generate a second excitation signal, and then inputs the second excitation signal to the second sensor 3021. After the second sensor 3021 detects the second excitation signal, the second excitation signal can be transmitted to the second excitation winding 3022. After the second excitation winding 3022 receives the second excitation signal, it can generate a flux signal proportional to the second excitation signal, and then generate a second target signal based on the flux signal, and transmit the second target signal to the controller 10. After receiving the second target signal, the controller 10 can analyze the linear characteristics between the second excitation signal and the second target signal, and then adjust the frequency and gain of the excitation signal output by the second excitation source 202 according to the linear characteristics to achieve optimal performance. The above-mentioned low-frequency closed-loop fluxgate circuit can be used for current monitoring in power transformers, and the accuracy of current measurement is ensured through closed-loop control. It is widely used in distribution network monitoring systems.

[0052] The high-frequency closed-loop fluxgate circuit described above can be used in motors and inverters to quickly detect instantaneous changes in current and effectively prevent equipment damage. The differences between low-frequency fluxgate circuits and high-frequency fluxgate circuits can be seen in the table below:

[0053]

[0054] The fluxgate circuits described in the embodiments of this application primarily rely on a feedback mechanism. They form a closed-loop system by comparing the sensor's output signal with a reference signal. This effectively reduces external interference and measurement errors, enabling high-precision current detection. High-frequency open-loop fluxgate circuits, on the other hand, do not employ a feedback mechanism and instead are driven directly by the input signal, resulting in a faster response.

[0055] In one embodiment, the feedback loop 40 includes a comparator 401 connected to the first sensing component 301 and the controller 10; the comparator 401 is used to compare the first target signal with the first expected signal to obtain a comparison result; and the controller 10 is used to determine a feedback signal based on the comparison result.

[0056] The comparator 401 may be a high-precision operational amplifier 501 to ensure a linear relationship between input and output. The feedback loop 40 may be designed with appropriate feedback resistors and capacitors to adjust the frequency response of the system and ensure system stability.

[0057] In an embodiment of the present application, the first sensing component 301 can input the first target signal into the comparator 401. After the comparator 401 obtains the first target signal, it can compare the first target signal with the first expected signal to obtain a comparison result, i.e., a feedback signal, and then return the comparison result to the controller 10. After receiving the comparison result, the controller 10 can determine the feedback signal based on the comparison result.

[0058] In one embodiment, Figure 4 As shown, the feedback loop 40 further includes: a gain adjuster 402 ; the gain adjuster 402 is connected to the output end of the controller 10 and the input end of the first excitation source 201 ; the controller 10 is used to control the gain adjuster 402 to adjust the gain of the excitation signal output by the first excitation source 201 .

[0059] According to the method described in the embodiment of the present application, after receiving the feedback signal, the controller 10 can generate a control instruction based on the feedback signal, and then send the control instruction to the gain regulator 402, which controls the gain regulator 402 to adjust the gain of the excitation signal output by the first excitation source 201 to optimize the system performance and ensure the sensitivity at different frequencies, so as to ensure that the system has the best performance within the required frequency range.

[0060] Combining all the above embodiments, Figure 4 As shown, a low-frequency closed-loop fluxgate circuit is also provided, which includes: a controller 10, a first excitation source 201, a first sensor 3011, a first excitation winding 3012, a comparator 401, a gain adjuster 402 and a filter component 404; the output end of the first excitation source 201 is connected to the input end of the first sensor 3011, the output end of the first sensor 3011 is connected to the input end of the first excitation winding 3012, the output end of the first excitation winding 3012 is connected to the input end of the comparator 401, the output end of the comparator 401 is connected to the first end of the controller 10, the second end of the controller 10 is connected to the input end of the gain adjuster 402, the output end of the gain adjuster 402 is connected to the input end of the first excitation source 201, the controller 10 is also connected to the input end of the first excitation source 201, and the filter component 404 is respectively arranged between the first excitation source 201 and the first sensor component 30130 and between the first sensor component 301 and the feedback loop 40.

[0061] Among them, the first excitation source 201 is used to generate a first excitation signal, the first sensor 3011 is used to detect the first excitation signal, the first excitation winding 3012 is used to generate a first target signal based on the first excitation signal, the comparator 401 is used to compare the first target signal with the first expected signal to obtain a comparison result, the controller 10 is used to determine a feedback signal based on the comparison result, and control the gain adjuster 402 to adjust the gain of the excitation signal output by the first excitation source 201 based on the feedback signal, and the filtering component 404 is used to eliminate the influence of high-frequency interference and noise on the sensor performance.

[0062] The working principle of the low-frequency fluxgate circuit is as follows: the controller 10 controls the first excitation source 201 to generate a first excitation signal, which is first input into the filter component 404 for filtering, and then input into the first sensor 3011. After the first sensor 3011 detects the first excitation signal, it can transmit the first excitation signal to the first excitation winding 3012. After receiving the first excitation signal, the first excitation winding 3012 can generate a flux signal proportional to the first excitation signal. A first target signal is then generated based on the flux signal, and the first target signal is input into the filter component 404 for filtering. The filtered first target signal is then transmitted to the comparator 401, which can compare the first target signal with the first expected signal to obtain a comparison result, i.e., a feedback signal. The feedback signal is then returned to the controller 10. After receiving the feedback signal, the controller 10 can generate a control instruction based on the feedback signal, and then send the control instruction to the gain adjuster 402. The gain adjuster 402 controls the gain adjuster 402 to adjust the gain of the excitation signal output by the first excitation source 201 to optimize system performance, ensure sensitivity at different frequencies, and ensure that the system has optimal performance within the required frequency range.

[0063] Example of introducing low-frequency closed-loop fluxgate circuit: (1) Principle explanation: Low-frequency closed-loop fluxgate circuit mainly relies on feedback mechanism. It compares the output signal of the sensor with the reference signal to form a closed-loop system. This can effectively reduce external interference and measurement error, thereby achieving high-precision current detection. (2) Working process: Sensor: The current signal detected by the sensor generates a magnetic flux proportional to the current through the excitation winding. Feedback control: The output signal is compared with the reference signal through the feedback loop 40, which adjusts the excitation signal to keep the output signal consistent with the input signal. Gain adjustment: In circuit design, adjust the gain to ensure that the system has optimal performance in the required frequency range. (3) Design of magnetic core and excitation coil: Material selection: Choose soft magnetic materials with high permeability, such as ferrite or silicon steel, to ensure low loss at low frequencies. Geometric design: Design appropriate magnetic core shape to optimize coil turns and winding layout, reducing leakage and hysteresis losses. (3) Construction of closed-loop control circuit: Comparator 401 selection: Choose a high-precision operational amplifier 501 as the comparator 401 to ensure linear relationship between input and output. Feedback path design: Design appropriate feedback resistors and capacitors to adjust the frequency response of the system and ensure system stability. Zero flux detection principle application: Use the zero flux principle to design a closed-loop system to achieve precise measurement of direct current. This usually involves a three-core four-winding structure, one winding for detecting average current (direct current zero flux detection), and the other two windings for suppressing the induced modulation ripple caused by transformer effect (alternating current zero flux detection). In the closed-loop system, the excitation current is adjusted through negative feedback mechanism to keep the magnetic flux in the core zero, thereby achieving high-precision measurement of the measured current. Digital circuit design: Introduce digital circuit method to simplify traditional analog signal processing modules. For example, use digital signal processors (DSP) or microcontrollers (MCU) to generate excitation signals, collect and process detection signals, etc. Through theoretical analysis of the relationship between excitation signal duty cycle and measured current amplitude, improve digital sensing accuracy. At the same time, design and optimize the negative feedback controller based on this structure to ensure the stability and accuracy of the closed-loop system. Filter and anti-interference design: Design effective filter circuit to eliminate high-frequency interference and noise affecting sensor performance. This includes input filter and output filter design, as well as power supply line filtering, etc. Use electromagnetic optimization design to avoid high-frequency signals interfering with the normal operation of the sensor. At the same time, through reasonable layout and wiring design, reduce signal interference and circuit power consumption. PCB layout and wiring optimization: Follow the design principles of high-density interconnection PCB technology to integrate more signal lines, components and interconnection methods into limited space.By optimizing wiring methods and using high-frequency materials to increase signal transmission speed and meet the growing demand for data transmission, consideration is given to device selection and manufacturing processes to achieve high-integration miniaturization of PCB board manufacturing to adapt to deployment requirements in power environments. (4) Calibration system: Establish a calibration standard: Use a known current source for calibration to ensure that the output signal accurately reflects the input current. Adjust gain: Optimize system performance by adjusting the gain in the feedback circuit to ensure sensitivity at different frequencies. (5) Testing and optimization: Performance testing: Test circuit performance in actual applications, collect output data and analyze its accuracy. Dynamic adjustment: Based on the test results, make necessary adjustments to the circuit to improve the dynamic response capability of the system.

[0064] like Figure 3 As shown, a low-frequency closed-loop fluxgate circuit and a high-frequency closed-loop fluxgate circuit are also provided, and the high-frequency closed-loop fluxgate circuit includes: a controller 10, a second excitation source 202, a second sensor 3021, a second excitation winding 3022, an amplifier 501 and a filter 502; the first end of the controller 10 is connected to the input end of the second excitation source 202, the output end of the second excitation source 202 is connected to the input end of the second sensor 3021, the output end of the second sensor 3021 is connected to the input end of the second excitation winding 3022, the output end of the second excitation winding 3022 is connected to the input end of the amplifier 501, the output end of the amplifier 501 is connected to the input end of the filter 502, and the output end of the filter 502 is connected to the second end of the controller 10.

[0065] Among them, the second excitation source 202 is used to generate a second excitation signal, the second sensor 3021 is used to detect the second excitation signal, the second excitation winding 3022 is used to generate a second target signal based on the second excitation signal, the amplifier 501 is used to amplify the second target signal to obtain an amplified second target signal, the filter 502 is used to filter the amplified second target signal to obtain a filtered second target signal, and the controller 10 is used to adjust the frequency and gain of the excitation signal output by the second excitation source 202 according to the relationship between the filtered second target signal and the second excitation signal.

[0066] The working principle of the high-frequency fluxgate circuit is as follows: the controller 10 controls the first excitation source 201 to generate a second excitation signal, and then inputs the second excitation signal to the second sensor 3021. After the second sensor 3021 detects the second excitation signal, the second excitation signal can be transmitted to the second excitation winding 3022. After the second excitation winding 3022 receives the second excitation signal, it can generate a flux signal proportional to the second excitation signal, and then generate a second target signal based on the flux signal, and transmit the second target signal to the controller 10. After receiving the second target signal, the controller 10 can analyze the linear characteristics between the second excitation signal and the second target signal, and then adjust the frequency and gain of the excitation signal output by the second excitation source 202 according to the linear characteristics to achieve optimal performance.

[0067] An example of a high-frequency open-loop fluxgate circuit: (1) Principle: The high-frequency open-loop fluxgate circuit does not use a feedback mechanism, but is directly excited according to the input signal. This method has a faster response speed in the high-frequency range, but may be lacking in sensitivity and linearity. (2) Working process: Direct excitation: The excitation signal is directly applied to the excitation winding of the sensor. The relationship between the sensor output signal and the input signal depends on the nonlinear characteristics of the magnetic core. Signal processing: Use preamplifier 501 and filter 502 to improve signal quality and ensure stability at high frequencies. (3) Selection of magnetic core material: High-frequency material: Select low-loss soft magnetic material (such as iron-nickel alloy) to ensure good performance at high frequencies. Magnetic core structure: Design a suitable magnetic core structure (such as ring or E-type) to improve sensing sensitivity. (4) Design of open-loop circuit: Excitation signal source: Select a high-frequency oscillator (such as a crystal oscillator) to provide a stable excitation signal to ensure frequency adjustability. In a high-frequency open-loop system, the generation and detection of the excitation signal are key. It is necessary to design appropriate excitation circuits and detection circuits to achieve fast response and high-precision measurement of the measured current. Considering the characteristics of high-frequency signals, it may be necessary to use differential amplifier circuits, high-speed comparators 401, etc. to extract the detection signal and perform appropriate processing and amplification on it. Circuit topology: Design a simple circuit topology to avoid complex feedback networks and ensure fast response. (5) Signal processing circuit design: Preamplifier 501: Use a high-gain low-noise amplifier 501 to enhance signal strength and improve anti-interference capabilities. Filter 502 design: Based on actual application requirements, design a suitable low-pass or band-pass filter 502 to filter noise and improve signal quality. (6) Performance testing and debugging: Signal testing: Test the circuit in a laboratory environment and record the relationship between output and input.

[0068] In the fluxgate circuit described in the embodiments of this application, the low-frequency closed-loop fluxgate circuit compares the sensor output signal with a reference signal through a feedback mechanism, effectively reducing external interference and measurement errors, and improving the accuracy of current measurement. The design using the zero-flux principle enables high-precision measurement of large DC currents, which is crucial for ensuring the safety and stability of power systems. The selection of high-permeability soft magnetic materials and optimized core geometry can reduce hysteresis losses and magnetic leakage, improving the circuit's sensitivity and response stability in the low-frequency range. Effective filtering circuits and anti-interference designs can eliminate high-frequency interference and noise in the circuit, ensuring signal reliability. In the high-frequency open-loop fluxgate circuit, the excitation signal is directly applied, enabling it to respond quickly. This fast response is crucial for instantaneous overload protection of motors and inverters. Designing a simple open-loop circuit topology and avoiding complex feedback networks helps improve response speed and reduce latency. By introducing digital signal processing technology, the signal processing process is made more flexible and efficient, improving the system's adaptability and intelligence. This can simplify traditional analog signal processing modules and enhance system reliability. Combining artificial intelligence and IoT technologies enables intelligent monitoring and control of current, improving overall system performance. Low-frequency closed-loop fluxgate circuits are suitable for power monitoring and precision instrumentation, while high-frequency open-loop circuits are ideal for high-frequency applications such as transient overload protection, demonstrating the flexibility and adaptability of the system design. Exploring the integration of fluxgate circuits can reduce production costs, improve system reliability and usability, and facilitate widespread application. High-density interconnected PCB design enables higher integration and miniaturization, facilitating the efficient placement of more components within a limited space and enhancing overall system performance and stability. A standardized calibration process allows for real-time adjustment of gain and performance parameters to ensure system sensitivity and accuracy at varying frequencies, further enhancing the reliability of the measurement system.

[0069] 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.

[0070] The above-described embodiments merely represent 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 application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements 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 fluxgate circuit, characterized in that: The fluxgate circuit includes: a controller, an excitation source, a sensing component, a feedback loop and a signal processing component; The controller is connected to the control end of the excitation source, the control end of the feedback loop and the control end of the signal processing component respectively; the output end of the feedback loop and the output end of the signal processing component are both connected to the input end of the excitation source; The controller is used to control the excitation source to generate an excitation signal, and to adjust the excitation source according to the feedback signal output by the feedback loop when the excitation signal is a low-frequency signal, and to adjust the excitation source according to the signal output by the signal processing component when the excitation signal is a high-frequency signal.

2. The circuit according to claim 1, wherein: The fluxgate circuit includes: a low-frequency fluxgate circuit and a high-frequency fluxgate circuit; The low-frequency fluxgate circuit includes: a first excitation source among the excitation sources, a first sensing component among the sensing components, and a feedback loop; the feedback loop is configured to determine the feedback signal based on a first target signal and a first expected signal output by the first sensing component, and to adjust the excitation signal output by the first excitation source based on the feedback signal; The high-frequency fluxgate circuit includes: a second excitation source among the excitation sources, a second sensing component among the sensing components, and the signal processing component; the signal processing component is used to adjust the frequency and gain of the excitation signal output by the second excitation source according to the relationship between the output signal and the input signal of the second sensing component.

3. The circuit according to claim 2, characterized in that The feedback loop includes: a comparator connected to the first sensing component and the controller; The comparator is used to compare the first target signal with the first expected signal to obtain a comparison result; The controller is configured to determine the feedback signal according to the comparison result.

4. The circuit according to claim 3, characterized in that The feedback loop further includes: a gain adjuster; the gain adjuster is connected to the output end of the controller and the input end of the first excitation source; The controller is used to control the gain adjuster to adjust the gain of the excitation signal output by the first excitation source.

5. The circuit according to any one of claims 2 to 4, characterized in that: The first sensing assembly includes a first sensor and a first excitation winding, wherein the input end of the first sensor is connected to the first excitation source, the output end of the first sensor is connected to the input end of the first excitation winding, and the output end of the first excitation winding is connected to the feedback loop; The first sensor is used to detect the first excitation signal generated by the first excitation source; The first excitation winding is configured to generate the first target signal according to the first excitation signal.

6. The circuit according to claim 5, characterized in that The first excitation winding includes a first magnetic core; the material of the first magnetic core is a soft magnetic material with high magnetic permeability, and the material of the first magnetic core includes ferrite or silicon steel sheet.

7. The circuit according to claim 2, characterized in that The low-frequency fluxgate circuit further includes: a filter component; the filter component is respectively arranged between the first excitation source and the first sensing component and between the first sensing component and the feedback loop.

8. The circuit according to claim 2, characterized in that The signal processing component includes: an amplifier and a filter; The input end of the amplifier is connected to the output end of the second sensing component, the output end of the amplifier is connected to the input end of the filter, and the output end of the filter is connected to the controller; The amplifier is used to amplify the output signal of the second sensor component to obtain an amplified output signal; The filter is used to filter the amplified signal to obtain a filtered output signal; The controller is used to adjust the frequency and gain of the excitation signal output by the second excitation source according to the relationship between the filtered output signal and the input signal.

9. The circuit according to claim 2 or 8, characterized in that The second sensing assembly includes a second sensor and a second excitation winding, the input end of the second sensor is connected to the second excitation source, the output end of the second sensor is connected to the input end of the second excitation winding, and the output end of the second excitation winding is connected to the amplifier; The second sensor is used to detect the second excitation signal generated by the second excitation source; The second excitation winding is used to generate a second target signal according to the second excitation signal.

10. The circuit according to claim 9, characterized in that The second excitation winding includes a second magnetic core; the material of the second magnetic core is a low-loss soft magnetic material, and the material of the second magnetic core includes an iron-nickel alloy; the structure of the second magnetic core is a ring structure or an E-shaped structure.

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