Flux gate circuit

Abstract

The invention relates to a magnetic flux gate circuit. The magnetic flux gate circuit comprises a controller, an excitation source, a sensing assembly, a feedback loop and a signal processing assembly, the controller is connected with the control end of the excitation source, the control end of the feedback loop and the control end of the signal processing assembly. The output end of the feedback loop and the output end of the signal processing assembly are connected with the input end of the excitation source. The controller is used for controlling the excitation source to generate an excitation signal, 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. According to the magnetic flux gate circuit, the excitation source is adjusted through the feedback signal output by the feedback loop, external interference and measurement errors can be effectively reduced, the measurement precision is improved, interference and noise in the circuit are eliminated through the signal processing assembly, high-frequency interference and noise are eliminated, and the reliability of the signal is guaranteed.

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 working principle of fluxgate sensor is based on the magnetic saturation characteristics of nonlinear magnetic core materials (such as Permalloy, amorphous and nanocrystalline materials) under the action of alternating magnetic field. When the measured magnetic field acts on the magnetic core, it will cause the change of magnetic flux in the magnetic core, and then generate induced electromotive force through the coil wound on the magnetic core. Since the induced electromotive force is related to the size 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 sensor component, a feedback loop and a signal processing component;

[0006] The controller is respectively 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; 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 comprises: a first excitation source in the excitation source, a first sensing component in the sensing component and a feedback loop; the feedback loop is used to determine a feedback signal according to 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 according to 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 for determining 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 sensor assembly includes a first sensor and a first excitation winding, 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 sensor component and between the first sensor 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 embodiment, 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;

[0027] The second sensor is used to detect the second excitation signal;

[0028] The second excitation winding is used to generate a second target signal according to a second excitation signal.

[0029] In one embodiment, 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-type structure.

[0030] The fluxgate circuit includes a controller, an excitation source, a sensing component, a feedback loop and a signal processing component; wherein the controller is respectively 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; 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. The fluxgate circuit adjusts the excitation source through the feedback signal output by the feedback loop, which can effectively reduce external interference and measurement errors, improve the measurement accuracy, and eliminate interference and noise in the circuit through the signal processing component, eliminate high-frequency interference and noise, and ensure the reliability of the signal. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0032] Figure 2 is a schematic diagram of the structure of a low-frequency fluxgate circuit in one embodiment;

[0033] Figure 3 is a schematic diagram of the structure of a high-frequency fluxgate circuit in one embodiment;

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

[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 solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] The working principle of the fluxgate sensor is based on the magnetic saturation characteristics of nonlinear magnetic core materials (such as Permalloy, amorphous and nanocrystalline materials) under the action of an alternating magnetic field. When the measured magnetic field acts on the magnetic core, it will cause a change in the magnetic flux in the magnetic core, and then generate an induced electromotive force through the coil wound on the magnetic core. Since the induced electromotive force is related to the size and direction of the measured magnetic field, it can be used to measure the magnetic field. However, the fluxgate sensor in the related art is susceptible to environmental interference during the measurement of the magnetic field, and has the problem of 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 sensor component 30, a feedback loop 40 and a signal processing component 50;

[0040] 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 used to control the excitation source 20 to generate an excitation signal, and when the excitation signal is a low-frequency signal, adjust the excitation source 20 according to the feedback signal output by the feedback loop 40, and when the excitation signal is a high-frequency signal, adjust the excitation source 20 according to the signal output by the signal processing component 50. The excitation source 20 is used to generate an excitation signal, and the excitation source 20 can be a current source, a voltage source, an oscillator, a signal generator, etc. 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 used to generate a low-frequency excitation signal, and the second excitation source 202 is used to generate a high-frequency excitation signal. The sensor component 30 is used 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 used to determine the feedback signal according to the first target signal and the first standard signal. The signal processing component 50 is used to enhance the target signal output by the sensor 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. The first standard signal is determined according to actual needs, and can be determined according to actual measurement accuracy.

[0042] The fluxgate circuit provided in the embodiment of the present application includes a controller, an excitation source, a sensing component, a feedback loop, and a signal processing component; wherein the controller is respectively 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 used to control the excitation source to generate an excitation signal, and adjust the excitation source according to the feedback signal output by the feedback loop, and adjust the excitation source according to the target signal output by the signal processing component. The above-mentioned fluxgate circuit adjusts the excitation source through the feedback signal output by the feedback loop, which can effectively reduce external interference and measurement errors, improve the measurement accuracy, and eliminate interference and noise in the circuit through the signal processing component, eliminate high-frequency interference and noise, and ensure the reliability of the signal.

[0043] In one embodiment, the fluxgate circuit comprises: a low-frequency fluxgate circuit and a high-frequency fluxgate circuit;

[0044] Among them, Figure 2As shown, the low-frequency fluxgate circuit includes: a first excitation source 201 in the excitation source 20, a first sensor component 301 in the sensor component 30, and a feedback loop 40; the feedback loop 40 is used to determine a feedback signal according to the first target signal and the first expected signal output by the first sensor component 30130, and adjust the excitation signal output by the first excitation source 201 according to the feedback signal. The first sensor component 301 includes a first sensor 3011 and a first excitation winding 3012, the input end of the first sensor 3011 is connected to the first excitation source 201, the output end of the first sensor 3011 is connected to the input end of the first excitation winding 3012, and the output end of the first excitation winding 3012 is connected to the feedback loop 40. 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 according to the first excitation signal. The 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, which ensures that it has low loss at low frequency. The shape of the first magnetic core is designed based on the principle of optimizing the number of coil turns and winding layout, and reducing leakage magnetic flux and hysteresis loss.

[0045] The above-mentioned low-frequency fluxgate circuit can adopt the zero flux principle and design a closed-loop system to achieve precise measurement of large DC currents. It can be a three-core four-winding structure, in which one winding is used to detect the average current (DC zero flux detection), and the other two windings are used to suppress the inductive modulation ripple caused by the transformer effect (AC zero flux detection). In the closed-loop system, the excitation current is adjusted through a negative feedback mechanism to keep the magnetic flux in the core at zero, thereby achieving high-precision measurement of the measured current.

[0046] The above-mentioned low-frequency fluxgate circuit can introduce digital circuit methods to simplify the modules of traditional analog signal processing. For example, a digital signal processor (DSP) or a microcontroller (MCU) is used to realize the functions of generating excitation signals, collecting and processing detection signals, and improving the accuracy of digital sensing by theoretically analyzing the relationship between the duty cycle of the excitation signal and the amplitude of the measured current. At the same time, the negative feedback controller is designed and optimized based on this structure to ensure the stability and accuracy of the closed-loop system. At the same time, signal interference and circuit power consumption are reduced through reasonable layout and routing design. The above-mentioned low-frequency fluxgate circuit can follow the design principles of high-density interconnected PCB technology to integrate more signal lines, components and interconnection methods into a limited space. By optimizing the wiring method and using high-frequency materials to increase the signal transmission speed, meet the growing demand for data transmission, consider the device selection and manufacturing process, and realize the high integration and miniaturization of PCB board making to meet 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 the controller 10 receives the feedback signal, it 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 above-mentioned low-frequency fluxgate circuit also includes: a filter component 404; the filter component 404 is respectively arranged 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 influence of high-frequency interference and noise on the performance of the sensor. This includes the design of the input filter 502 and the output filter 502, as well as the filtering processing of the power supply line, etc., and adopts electromagnetic optimization design to avoid high-frequency signals from interfering with the normal operation of the sensor.

[0049] Among them, 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 component 50 includes: an amplifier 501 and a filter 502; the input end of the amplifier 501 is connected to the output end of the second sensor component 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 sensor component 30230 to 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 to obtain a filtered output signal to filter noise and improve signal quality, so as to improve signal quality and ensure stability at high frequencies. 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 component 302 includes 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 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 to ensure good performance at high frequencies. The structure of the second magnetic core is a ring structure or an E-type structure to improve the sensing sensitivity. The input signal of the second sensing component 302 is the second excitation signal, and the output signal of the second sensing component 302 is the second target signal. The second excitation source 202 is a high-frequency oscillator (such as a crystal oscillator) 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 key. Design a suitable excitation circuit and detection circuit 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 a differential amplifier circuit, a high-speed comparator 401, etc. to extract the detection signal, and perform appropriate processing and amplification on it. Design a simple circuit topology to avoid complex feedback networks 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 according to the flux signal, and transmit the second target signal to the controller 10. After the controller 10 receives the second target signal, it 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, and it is widely used in distribution network monitoring systems.

[0052] The above high-frequency closed-loop fluxgate circuit 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 following table:

[0053]

[0054] The fluxgate circuit described in the embodiment of the present application, the low-frequency closed-loop fluxgate circuit mainly relies on the feedback mechanism. It forms a closed-loop system by comparing the output signal of the sensor with the reference signal. This can effectively reduce external interference and measurement errors, thereby achieving high-precision current detection. The high-frequency open-loop fluxgate circuit does not use a feedback mechanism, but is directly excited according to the input signal, and has a faster response speed.

[0055] In one embodiment, the feedback loop 40 includes: a comparator 401, which is connected to the first sensor 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 the feedback signal according to 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 to 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 regulator 402 ; the gain regulator 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 regulator 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 adjuster 402, which controls the gain adjuster 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 according to 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 according to the comparison result, and control the gain adjuster 402 to adjust the gain of the excitation signal output by the first excitation source 201 according to 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, first inputs the first excitation signal into the filter component 404 for filtering, and then inputs the filtered first excitation signal into 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 input the first target signal into the filter component 404 for filtering, and then transmit the filtered first target signal to the comparator 401, and the first target signal can be compared with the first expected signal to obtain a comparison result, i.e., a feedback signal, and then the feedback signal is returned to the controller 10. After receiving the feedback signal, the controller 10 can generate a control instruction according to the feedback signal, and then send the control instruction to the gain adjuster 402, and control the gain adjuster 402 to adjust the gain of the excitation signal output by the first excitation source 201 to optimize the system performance, ensure the sensitivity at different frequencies, and ensure that the system has the best performance within the required frequency range.

[0063] An exemplary introduction to the low-frequency closed-loop fluxgate circuit: (1) Principle explanation: The low-frequency closed-loop fluxgate circuit mainly relies on the feedback mechanism. It forms a closed-loop system by comparing the output signal of the sensor with the reference signal. This can effectively reduce external interference and measurement errors, 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, and the feedback loop 40 adjusts the excitation signal so that the output signal is consistent with the input signal. Gain adjustment: In circuit design, the gain is adjusted to ensure that the system has the best performance within the required frequency range. (3) Design of magnetic core and excitation coil: Material selection: Select soft magnetic materials with high magnetic permeability, such as ferrite or silicon steel sheet, to ensure that it has low loss at low frequencies. Geometric design: Design an appropriate core shape to ensure the optimization of the number of coil turns and winding layout, and reduce leakage and hysteresis losses. (3) Construct a closed-loop control circuit: Comparator 401 selection: Select a high-precision operational amplifier 501 as comparator 401 to ensure a 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. Application of zero flux detection principle: Adopt the zero flux principle to design a closed-loop system to achieve precise measurement of large DC currents. This usually involves a three-core four-winding structure, in which one winding is used to detect the average current (DC zero flux detection) and the other two windings are used to suppress the inductive modulation ripple caused by the transformer effect (AC zero flux detection). In the closed-loop system, the excitation current is adjusted through a 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 methods to simplify the modules of traditional analog signal processing. For example, use a digital signal processor (DSP) or a microcontroller (MCU) to realize the generation of excitation signals, the acquisition and processing of detection signals, and improve the accuracy of digital sensing by theoretically analyzing the relationship between the duty cycle of the excitation signal and the amplitude of the measured current. At the same time, the negative feedback controller is designed and optimized based on this structure to ensure the stability and accuracy of the closed-loop system. Filtering and anti-interference design: Design an effective filtering circuit to eliminate the impact of high-frequency interference and noise on sensor performance. This includes the design of input filters and output filters, as well as filtering of power supply lines, etc. Electromagnetic optimization design is used to avoid interference of high-frequency signals on the normal operation of the sensor. At the same time, through reasonable layout and routing design, signal interference and circuit power consumption are reduced. PCB layout and routing optimization: Follow the design principles of high-density interconnect PCB technology to integrate more signal lines, components and interconnection methods into a limited space.By optimizing the wiring method and using high-frequency materials to increase the signal transmission speed, the growing demand for data transmission is met. Considerations are made in device selection and manufacturing processes to achieve high integration and miniaturization of PCB board making to meet the deployment requirements in the power environment. (4) Calibration system: Establish calibration standards: 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: Make necessary adjustments to the circuit based on the test results 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 according to 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 according to 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 exemplary introduction to a high-frequency open-loop fluxgate circuit: (1) Principle explanation: 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 lack 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 materials (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 an 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 properly process and amplify 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 ability. Filter 502 design: According to 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 embodiment of the present application, the low-frequency closed-loop fluxgate circuit compares the sensor output signal with the 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 can achieve high-precision measurement of large DC currents, which is essential for ensuring the safety and stability of the power system. Selecting soft magnetic materials with high magnetic permeability and optimized core geometry design can reduce hysteresis loss and magnetic leakage, and improve the sensitivity and response stability of the circuit in the low-frequency range. Through effective filtering circuits and anti-interference designs, high-frequency interference and noise can be eliminated in the circuit to ensure the reliability of the signal. In the high-frequency open-loop fluxgate circuit, the excitation signal is directly applied to enable it to have the ability to respond quickly. This fast response is essential for instantaneous overload protection of motors and frequency converters. Designing a simple open-loop circuit topology and avoiding complex feedback networks can help improve response speed and reduce delays. By introducing digital signal processing technology, the signal processing process is made more flexible and efficient, and the adaptive ability and intelligence level of the system are improved. This can simplify the modules of traditional analog signal processing and enhance the reliability of the system. Combining artificial intelligence and Internet of Things technologies, intelligent monitoring and control of current can be achieved, improving the overall performance of the system. Low-frequency closed-loop fluxgate circuits are suitable for power monitoring and precision instruments, while high-frequency open-loop circuits are suitable for high-frequency application scenarios such as instantaneous overload protection, demonstrating the flexibility and adaptability of system design. By exploring the integration of fluxgate circuits, production costs can be reduced, system reliability and ease of use can be improved, and convenience can be provided for a wide range of applications. Through high-density interconnected PCB design, higher integration and miniaturization can be achieved, which helps to efficiently arrange more components in a limited space and improve the overall performance and stability of the system. A standardized calibration process is established to adjust the gain and performance parameters in real time to ensure the sensitivity and accuracy of the system at different frequencies, further improving the reliability of the measurement system.

[0069] The technical features of the above embodiments may be arbitrarily combined. 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 only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A fluxgate circuit, characterized in that: The fluxgate circuit includes: a controller, an excitation source, a sensor component, a feedback loop and a signal processing component; The controller is respectively 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; 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, characterized in that The fluxgate circuit comprises: a low-frequency fluxgate circuit and a high-frequency fluxgate circuit; The low-frequency fluxgate circuit comprises: a first excitation source among the excitation sources, a first sensing component among the sensing components, and the feedback loop; the feedback loop is used to determine the feedback signal according to the first target signal and the first expected signal output by the first sensing component, and to adjust the excitation signal output by the first excitation source according to 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, the comparator connecting 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 used 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 regulator; the gain regulator 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 component includes a first sensor and a first excitation winding, 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 used 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 sensor component and between the first sensor 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; Wherein, 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; 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 an 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-type structure.

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