Device and method for suppressing excitation frequency noise of fluxgate current sensor

Abstract

The present invention provides a device and method for suppressing the excitation frequency noise of a fluxgate current sensor, comprising a fluxgate structure having a primary winding passing through two circular magnetic cores and a secondary winding divided into first and second windings that generate excitation currents in opposite directions. A compensation winding is wound around the two circular magnetic cores and connected to a compensation power supply and a load resistor. A filtering and demodulation circuit filters the excitation currents of the first and second windings to obtain a measurement signal. A PI controller receives the measurement signal and outputs a feedback current to maintain zero flux. A signal acquisition and noise spectrum analysis module analyzes the noise spectrum of the output signal and controls the compensation power supply to output a compensation current. The compensation winding current is a superposition of the feedback current and the compensation current, and a voltage signal is output through the load resistor. The present invention solves the noise problem caused by the excitation current by adding a compensation winding and a magnetic core and analyzing the specific frequency noise in the output signal to control an external current source to apply a compensation current to the compensation winding.

Description

Technical field

[0001] The present invention relates to a fluxgate current sensor, in particular to a device and method for suppressing excitation frequency noise of the fluxgate current sensor. [Background Technology]

[0002] Fluxgate current sensors are widely used in scientific research, industrial production, and power grid monitoring due to their low cost, high accuracy, and wide measurement range. However, for even-order or second-harmonic detection fluxgate current sensors, whether using self-oscillation or external excitation, the transformer effect causes the excitation square wave current to distort the magnetization of the sensor core, generating modulated ripple in the output signal. This ripple degrades measurement accuracy and becomes a key performance limiting factor.

[0003] Wang Nong and others from Harbin Institute of Technology proposed a three-core fluxgate current sensor design. By combining a self-oscillating fluxgate with a magnetic integrator in a common feedback loop, they maintain a closed-loop zero-flux state. They analyzed the mechanism of modulation ripple caused by transformer effects and proposed a method to suppress this ripple by adding windings and using a high-pass filter. However, this method requires high manufacturing consistency for the excitation and compensation windings and the core, which increases design and manufacturing complexity. Furthermore, the additional windings and cores further complicate the system.

[0004] Wei Yutong and others from ShanghaiTech University proposed an electrical compensation scheme to suppress the magnetization distortion caused by the excitation current. This scheme offsets the magnetization distortion by injecting a compensation current corresponding to the excitation current cycle at the sensor output. However, the algorithm used in this electrical compensation scheme is complex, resulting in limited effectiveness and no significant advantages over commercial current sensors.

[0005] In addition to harmonic detection fluxgate sensors, researchers have also proposed a fluxgate sensing principle based on residence time difference detection. Fluxgate current sensors based on this principle are more common in micro-nanofabrication. While they can effectively suppress noise introduced by the excitation current, their current measurement range is limited and may not meet the needs of a wider range of applications.

[0006] In summary, in harmonic detection type fluxgate sensors, although the method of adding windings and magnetic cores can suppress the modulation ripple to a certain extent, this method has high requirements on the consistency of the windings and magnetic cores, which increases the difficulty of design and processing. Although the electrical compensation scheme takes into account the periodicity of the excitation current, its algorithm is complex and the compensation effect is limited, and its advantages are not obvious compared with commercial current sensors. As for the residence time difference detection type fluxgate sensor, although it can suppress the excitation current noise in principle, its small measurement range limits its application in scientific research and industrial production scenarios. Therefore, the commonly used type of fluxgate sensor is still the harmonic detection type. The present invention proposes a method for suppressing excitation frequency noise for harmonic detection type fluxgate sensors. [Summary of the invention]

[0007] This invention aims to provide a device and method for suppressing excitation frequency noise in a fluxgate current sensor. This device addresses the excitation frequency noise problem in fluxgate current sensors by employing a harmonic detection sensor solution and introducing a compensation winding and magnetic core. By analyzing the sensor output signal, identifying specific frequency noise, and applying a compensation current of the corresponding frequency to offset the excitation current noise, the device reduces the need for winding and core consistency and simplifies manufacturing.

[0008] To achieve the aforementioned object of the invention, in a first aspect, the present invention provides a device for suppressing excitation frequency noise of a fluxgate current sensor, comprising:

[0009] A fluxgate structure includes two circular magnetic cores, a primary winding, a secondary winding, a compensation winding, a compensation power supply, and a load resistor; the secondary winding includes a first winding and a second winding; the primary winding passes through both circular magnetic cores simultaneously and is passed through a primary current; the first winding and the second winding are respectively connected to an excitation module on each of the circular magnetic cores, with the windings having opposite orientations; the first winding generates a first excitation current, and the second winding generates a second excitation current; the compensation winding is wound around both circular magnetic cores simultaneously, with the input end connected to the compensation power supply, and the output end outputs a voltage signal through the load resistor;

[0010] a filtering and demodulation circuit, connected to the first winding and the second winding, respectively, for filtering the first excitation current and the second excitation current to obtain a measurement signal of the fluxgate current sensor;

[0011] a PI controller (proportional-integral controller), connected between the filtering and demodulation circuit and the input end of the compensation winding, for receiving the measurement signal and outputting a feedback current for maintaining zero flux in the fluxgate to the compensation winding;

[0012] a signal acquisition and noise spectrum analysis module, connected between the filtering and demodulation circuit and the compensation power supply, for converting the analog signal output by the filtering and demodulation circuit into a digital signal, performing noise spectrum analysis, and obtaining noise spectrum analysis results of the first excitation current and the second excitation current; and controlling the compensation power supply to output compensation currents having the same frequency, consistent intensity, and opposite directions to the compensation winding based on the noise spectrum analysis results;

[0013] The current on the compensation winding is formed by the superposition of the feedback current and the compensation current, and outputs a voltage signal via the load resistor.

[0014] In a second aspect, the present invention provides a device for suppressing excitation frequency noise of a fluxgate current sensor, comprising:

[0015] A fluxgate structure includes two circular magnetic cores, a primary winding, a secondary winding, a compensation winding, a compensation power supply, and a load resistor; the secondary winding includes a first winding and a second winding; the primary winding passes through both circular magnetic cores simultaneously and is passed through a primary current; the first winding and the second winding are respectively connected to an excitation module on each of the circular magnetic cores, with the windings having opposite orientations; the first winding generates a first excitation current, and the second winding generates a second excitation current; the compensation winding is wound around both circular magnetic cores simultaneously, with the input end connected to the compensation power supply, and the output end outputs a voltage signal through the load resistor;

[0016] a filtering and demodulation circuit, connected to the first winding and the second winding, respectively, for filtering the first excitation current and the second excitation current to obtain a measurement signal of the fluxgate current sensor;

[0017] a PI controller connected between the filtering and demodulation circuit and the input end of the compensation winding, configured to receive the measurement signal and output a feedback current for maintaining zero flux in the fluxgate to the compensation winding;

[0018] a notch filter connected between the filtering and demodulation circuit and the compensation power supply, configured to obtain a noise value of the excitation frequency of the measurement signal, and use the noise value to control the compensation power supply to output a compensation current with the same frequency, consistent intensity and opposite direction to the compensation winding;

[0019] The current on the compensation winding is formed by the superposition of the feedback current and the compensation current, and outputs a voltage signal via the load resistor.

[0020] In a third aspect, the present invention provides a method for suppressing the excitation frequency noise of a fluxgate current sensor, which uses the device for suppressing the excitation frequency noise of the fluxgate current sensor as described in the first aspect to perform the following suppression process:

[0021] S11, the excitation module generates an excitation current and sends it to the first winding and the second winding, respectively generating a first excitation current and a second excitation current and sending them to the filtering and demodulation circuit respectively;

[0022] S12, the filtering and demodulation circuit filters the first excitation current and the second excitation current to obtain frequency and phase information, and sends the frequency and phase information as measurement signals of the fluxgate current sensor to the PI controller and the signal acquisition and noise spectrum analysis module respectively;

[0023] S13, after receiving the measurement signal, the PI controller outputs a feedback current for maintaining zero magnetic flux in the fluxgate;

[0024] At the same time, the signal acquisition and noise spectrum analysis module converts the measurement signal into a digital signal and then performs noise spectrum analysis to obtain a noise spectrum analysis result of the measurement signal, detects the excitation frequency and noise peak value in the noise spectrum analysis result, and sends the detected excitation frequency and noise peak value to the compensation power supply to control the compensation power supply to output a compensation current with the same frequency, consistent intensity and opposite direction;

[0025] S14, the feedback current and the compensation current are added to obtain a superimposed current which is fed into the compensation winding. The superimposed current passes through a load resistor to obtain an output voltage signal of a fluxgate current sensor.

[0026] In a fourth aspect, the present invention provides a method for suppressing the excitation frequency noise of a fluxgate current sensor, which uses the device for suppressing the excitation frequency noise of the fluxgate current sensor as described in the second aspect to perform the following suppression process:

[0027] S21, the excitation module generates an excitation current and sends it to the first winding and the second winding, respectively generating a first excitation current and a second excitation current and sending them to the filtering and demodulation circuit respectively;

[0028] S22, the filtering and demodulation circuit filters the first excitation current and the second excitation current to obtain frequency and phase information, and sends the frequency and phase information as measurement signals of the fluxgate current sensor to the PI controller and the notch filter respectively;

[0029] S23, after receiving the measurement signal, the PI controller outputs a feedback current for maintaining zero magnetic flux in the fluxgate;

[0030] At the same time, the notch filter obtains the noise value of the excitation frequency of the measurement signal, and uses the noise value to control the compensation power supply to output a compensation current with the same frequency, consistent intensity and opposite direction to the compensation winding;

[0031] S24, the feedback current and the compensation current are added to obtain a superimposed current which is fed into the compensation winding. The superimposed current passes through a load resistor to obtain an output voltage signal of a fluxgate current sensor.

[0032] The advantages of the present invention are:

[0033] 1. The present invention solves the noise problem caused by the excitation current in the fluxgate current sensor by adding a compensation winding and a magnetic core to the sensor and analyzing the specific frequency noise generated by the excitation current in the output signal. It can thus control the external current source to apply a compensation current with the same frequency, consistent intensity and opposite direction to the compensation winding, thereby solving the noise problem caused by the excitation current in the fluxgate current sensor.

[0034] 2. The fluxgate sensor used in the excitation frequency noise suppression device of the present invention is based on the harmonic detection type. Compared with the fluxgate sensor of the residence time difference detection type, it allows the design of a solution with a larger current measurement dynamic range at the principle level.

[0035] 3. The present invention adopts active compensation current technology, which reduces the consistency requirements for the winding and the magnetic core, thereby simplifying the processing process.

[0036] 4. The hardware structure and calculation method used in the present invention are relatively simple.

[0037] 5. Experimental results show that by analyzing the specific frequency noise in the sensor output signal and actively applying a compensation current of the corresponding frequency, the noise peak at the excitation frequency in the compensated sensor noise spectrum is reduced to less than 0.1% of the pre-compensation level.

Brief Description of the Drawings

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] Figure 1 It is a structural diagram of a first embodiment of a device for suppressing excitation frequency noise of a fluxgate current sensor according to the present invention.

[0040] Figure 2 It is a structural diagram of a second embodiment of a device for suppressing excitation frequency noise of a fluxgate current sensor according to the present invention.

[0041] Figure 3 It is a structural schematic diagram of a third embodiment of a device for suppressing excitation frequency noise of a fluxgate current sensor according to the present invention.

[0042] Figure 4 It is a structural diagram of an embodiment of a method for suppressing excitation frequency noise of a fluxgate current sensor of the present invention.

[0043] Figure 5It is a structural schematic diagram of another embodiment of the method for suppressing excitation frequency noise of a fluxgate current sensor of the present invention.

[0044] Figure 6 This is an example diagram of the excitation frequency noise suppression effect of the present invention.

[0045] The label description is as follows:

[0046] Fluxgate structure 1, circular magnetic core 11, primary winding 12, secondary winding 13, compensation winding W3, compensation power supply 15, load resistor R3; first winding W1, second winding W2, excitation module 16, primary current I P , the first excitation current I1, the second excitation current I2, the feedback current I R , compensation current I3;

[0047] Filtering and demodulation circuit 2; PI controller 3; signal acquisition and noise spectrum analysis module 4; notch filter 6. [Specific implementation method]

[0048] Embodiments of the present invention provide a device and method for suppressing excitation frequency noise in a fluxgate current sensor. This device addresses the excitation frequency noise problem in fluxgate current sensors by employing a harmonic detection sensor solution and introducing a compensation winding and magnetic core. By analyzing the sensor output signal, identifying specific frequency noise, and applying a compensation current of the corresponding frequency to offset the excitation current noise, the device reduces the need for winding and core consistency and simplifies manufacturing.

[0049] The technical solution in the embodiment of the present invention is to solve the above-mentioned problem. The overall idea is as follows: The present invention focuses on the problem of effectively suppressing the noise introduced by the excitation current in the fluxgate current sensor. Based on the harmonic detection fluxgate current sensor solution, while introducing the compensation winding and the magnetic core, the specific frequency noise introduced by the excitation current is analyzed by collecting the output signal of the sensor, and the external current source is controlled to actively apply a compensation current with the same frequency to the compensation winding. The intensity of the compensation current is adjusted to offset the excitation current noise as much as possible. The above process can be implemented using an automated test circuit, and due to the method of injecting active compensation current, the consistency requirements for the winding and the magnetic core are reduced, which correspondingly reduces the difficulty of processing.

[0050] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0051] Example 1

[0052] See also Figure 1As shown, this embodiment provides a device for suppressing excitation frequency noise of a fluxgate current sensor, which includes a fluxgate structure 1, a filtering and demodulation circuit 2, a PI controller 3, and a signal acquisition and noise spectrum analysis module 4.

[0053] The fluxgate structure 1 includes two circular magnetic cores 11, a primary winding 12, a secondary winding 13, a compensation winding W3, a compensation power supply 15, and a load resistor R3; the secondary winding 13 includes a first winding W1 and a second winding W2; the primary winding 11 passes through the two circular magnetic cores 11 at the same time and is passed through a primary current I p The first winding W1 and the second winding W2 are respectively wound on the circular magnetic core 11 and connected to an excitation module 16, and the winding orientations are opposite. The first winding W1 generates a first excitation current I1, and the second winding W2 generates a second excitation current I2. The compensation winding W3 is wound around the two circular magnetic cores 11 at the same time, the input end is connected to the compensation power supply 15, and the output end outputs a voltage signal through the load resistor R3.

[0054] The device for suppressing excitation frequency noise in a fluxgate current sensor of the present invention is applicable to both externally excited and self-oscillating fluxgate current sensor solutions. Specifically, this embodiment is for an externally excited fluxgate current sensor, where the excitation module 16 is an excitation power supply connected to the first winding W1 and the second winding W2 via a current-limiting resistor. Therefore, both the first excitation current I1 and the second excitation current I2 are external excitation currents.

[0055] a filtering and demodulation circuit 2, connected to the first winding W1 and the second winding W2, respectively, for filtering the first excitation current I1 and the second excitation current I2 to obtain a measurement signal of the fluxgate current sensor;

[0056] The PI controller 3, i.e. the proportional-integral controller, is connected between the filtering and demodulation circuit 2 and the input end of the compensation winding W3, and is used to receive the measurement signal and output a feedback current I to keep the fluxgate zero flux. R to the compensating winding W3;

[0057] a signal acquisition and noise spectrum analysis module 4 connected between the filtering and demodulation circuit 2 and the compensation power supply 15, configured to convert the analog signal output by the filtering and demodulation circuit 2 into a digital signal, perform noise spectrum analysis, and obtain noise spectrum analysis results of the first excitation current I1 and the second excitation current I2; and control the compensation power supply 15 to output a compensation current I3 having the same frequency, consistent intensity, and opposite direction to the compensation winding W3 based on the noise spectrum analysis results;

[0058] The current on the compensation winding W3 is determined by the feedback current IR The voltage signal is output through the load resistor R3 and the compensation current I3 is superimposed.

[0059] The suppression device of the present invention is applicable to both externally excited and self-oscillated fluxgate current sensor solutions. This embodiment 1 shows a device for suppressing the excitation frequency noise of an externally excited fluxgate current sensor. The schematic diagram of its structure is shown in FIG. Figure 1 As shown in FIG, the second embodiment is a device for suppressing the excitation frequency noise of the self-excited oscillation fluxgate current sensor, and its structural schematic diagram is shown in FIG. Figure 2 shown.

[0060] For the device for suppressing the excitation frequency noise of the externally excited fluxgate current sensor, the compensation power supply 15 and the excitation power supply 16 are two channels Ch1 and Ch2 of an AC current source, and the frequencies of the two channels Ch1 and Ch2 are synchronized, and the phase relationship is kept constant;

[0061] In this embodiment, the design performance of the two circular magnetic cores 11 is consistent, but the processing performance is not required to be consistent. The noise problem caused by the inconsistency can be solved by the suppression solution of the present invention.

[0062] The filtering function of the filtering and demodulation circuit 2 is realized by a high-pass filter, a low-pass filter, or a combination of a high-pass filter and a low-pass filter.

[0063] The PI controller 3 is a digital PI controller or an analog PI controller.

[0064] Example 2

[0065] See also Figure 2 As shown, the second embodiment provides a device for suppressing the excitation frequency noise of a fluxgate current sensor, which is aimed at a self-oscillating fluxgate current sensor. The only difference between the suppression device of the second embodiment and the first embodiment is that: the excitation module 16 is a self-oscillator, and the self-oscillator is connected to the first winding W1 through a current limiting resistor R1, connected to the second winding W2 through a current limiting resistor R2, and connected to the second winding W2 through a high-precision resistor R T grounded; then the first excitation current I1 and the second excitation current I2 are both self-excited oscillation currents.

[0066] In the self-oscillation scheme of this embodiment, the frequency and phase of the self-oscillator are measured by the phase-sensitive detection section of the filtering and demodulation circuit 2. This frequency and phase information is then transmitted to the compensation power supply 15, which generates the compensation current I3. This ensures that the frequency of the compensation current I3 and the excitation current are consistent, and their phase relationship is constant, which helps improve the suppression rate of the excitation current noise.

[0067] Example 3

[0068] See also Figure 3 As shown, this third embodiment provides a device for suppressing the excitation frequency noise of a fluxgate current sensor. The fluxgate current sensor is an integrated fluxgate current sensor. The structure of the device differs from that of the first or second embodiment only in that the signal acquisition and noise spectrum analysis module 4 is replaced by a notch filter 6. That is:

[0069] A notch filter 6 is connected between the filtering and demodulation circuit 2 and the compensation power supply 15. The notch filter 6 is used to obtain the noise value of the excitation frequency of the measurement signal, and use the noise value to control the compensation power supply 15 to output a compensation current I3 with the same frequency, consistent intensity and opposite direction to the compensation winding W3.

[0070] Example 4

[0071] See also Figure 4 As shown, this fourth embodiment provides a method for suppressing the excitation frequency noise of a fluxgate current sensor, and the apparatus for suppressing the excitation frequency noise of the fluxgate current sensor described in the first and second embodiments performs the following suppression process:

[0072] S11, the excitation module 16 generates an excitation current and sends it to the first winding W1 and the second winding W2, respectively generating a first excitation current I1 and a second excitation current I2 and sending them to the filtering and demodulation circuit 2 respectively;

[0073] When the excitation module 16 is an excitation power supply (see Example 1), before S1, an AC current source with two channels can be used, and the frequencies of the two channels can be synchronized, and the phase relationship can be kept constant. The two channels can be used as the compensation power supply 15 and the excitation power supply respectively.

[0074] When the excitation module 16 is a self-excited oscillator (see Example 2), the filtering and demodulation circuit 2 filters the first excitation current I1 and the second excitation current I2 to obtain frequency and phase information, and transmits the frequency and phase information to the compensation power supply 15.

[0075] S12, the filtering and demodulation circuit 2 filters the first excitation current I1 and the second excitation current I2 to obtain frequency and phase information, and sends the frequency and phase information as measurement signals of the fluxgate current sensor to the PI controller 3 and the signal acquisition and noise spectrum analysis module 4 respectively;

[0076] S13, the PI controller 3 outputs a feedback current for maintaining zero magnetic flux in the fluxgate after receiving the measurement signal;

[0077] At the same time, the signal acquisition and noise spectrum analysis module 4 converts the measurement signal into a digital signal and then performs noise spectrum analysis to obtain a noise spectrum analysis result of the measurement signal, detects the excitation frequency and noise peak value in the noise spectrum analysis result, and sends the detected excitation frequency and noise peak value to the compensation power supply 15, controlling the compensation power supply 15 to output a compensation current I3 with the same frequency, consistent intensity and opposite direction;

[0078] S14, the feedback current and the compensation current I3 are added to obtain a superimposed current which is sent to the compensation winding W3. The superimposed current passes through the load resistor R3 to obtain an output voltage signal of the fluxgate current sensor.

[0079] Example 4

[0080] See also Figure 5 As shown, this fourth embodiment provides a method for suppressing the excitation frequency noise of a fluxgate current sensor, and the device for suppressing the excitation frequency noise of a fluxgate current sensor described in the third embodiment performs the following suppression process:

[0081] S21, the excitation module 16 generates an excitation current and sends it to the first winding W1 and the second winding W2, respectively generating a first excitation current I1 and a second excitation current I2 and sending them to the filtering and demodulation circuit 2 respectively;

[0082] When the excitation module 16 is an excitation power supply (see Example 1), before S1, an AC current source with two channels can be used, and the frequencies of the two channels can be synchronized, and the phase relationship can be kept constant. The two channels can be used as the compensation power supply 15 and the excitation power supply respectively.

[0083] When the excitation module 16 is a self-excited oscillator (see Example 2), the filtering and demodulation circuit 2 filters the first excitation current I1 and the second excitation current I2 to obtain frequency and phase information, and transmits the frequency and phase information to the compensation power supply 15.

[0084] S22, the filtering and demodulation circuit 2 filters the first excitation current I1 and the second excitation current I2 to obtain frequency and phase information, and sends the frequency and phase information as measurement signals of the fluxgate current sensor to the PI controller 3 and the notch filter 6 respectively;

[0085] S23, the PI controller 3 outputs a feedback current for maintaining zero magnetic flux in the fluxgate after receiving the measurement signal;

[0086] At the same time, the notch filter 6 obtains the noise value of the excitation frequency of the measurement signal, and uses the noise value to control the compensation power supply 15 to output a compensation current I3 with the same frequency, consistent intensity and opposite direction to the compensation winding W3;

[0087] S24 , the feedback current and the compensation current I3 are added to obtain a superimposed current which is sent to the compensation winding W3 . The superimposed current passes through the load resistor R3 to obtain an output voltage signal of the fluxgate current sensor.

[0088] like Figure 6 As shown in the figure, by analyzing the specific frequency noise in the sensor output signal and actively applying a compensation current of the corresponding frequency, the experimental results show that the noise peak at the excitation frequency in the compensated sensor noise spectrum is reduced to less than 0.1% of the pre-compensation noise.

[0089] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A device for suppressing excitation frequency noise of a fluxgate current sensor, characterized in that: include: A fluxgate structure includes two circular magnetic cores, a primary winding, a secondary winding, a compensation winding, a compensation power supply, and a load resistor; the secondary winding includes a first winding and a second winding; the primary winding passes through both circular magnetic cores and is supplied with a primary current; the first winding and the second winding are respectively wound around one of the circular magnetic cores and connected to an excitation module, with the windings having opposite orientations; the first winding generates a first excitation current, and the second winding generates a second excitation current; the compensation winding is wound around both circular magnetic cores, with its input end connected to the compensation power supply and its output end outputting a voltage signal through the load resistor; a filtering and demodulation circuit, connected to the first winding and the second winding, respectively, for filtering the first excitation current and the second excitation current to obtain a measurement signal of the fluxgate current sensor; a PI controller connected between the filtering and demodulation circuit and the input end of the compensation winding, configured to receive the measurement signal and output a feedback current for maintaining zero flux in the fluxgate to the compensation winding; a signal acquisition and noise spectrum analysis module, connected between the filtering and demodulation circuit and the compensation power supply, for converting the analog signal output by the filtering and demodulation circuit into a digital signal, and performing noise spectrum analysis to obtain noise spectrum analysis results of the first excitation current and the second excitation current; According to the noise spectrum analysis result, the compensation power supply is controlled to output a compensation current with the same frequency, consistent intensity and opposite direction to the compensation winding; The current on the compensation winding is formed by the superposition of the feedback current and the compensation current, and outputs a voltage signal via the load resistor.

2. A device for suppressing excitation frequency noise of a fluxgate current sensor, characterized in that: include: A fluxgate structure includes two circular magnetic cores, a primary winding, a secondary winding, a compensation winding, a compensation power supply, and a load resistor; the secondary winding includes a first winding and a second winding; the primary winding passes through both circular magnetic cores and is supplied with a primary current; the first winding and the second winding are respectively wound around one of the circular magnetic cores and connected to an excitation module, with the windings having opposite orientations; the first winding generates a first excitation current, and the second winding generates a second excitation current; the compensation winding is wound around both circular magnetic cores, with its input end connected to the compensation power supply and its output end outputting a voltage signal through the load resistor; a filtering and demodulation circuit, connected to the first winding and the second winding, respectively, for filtering the first excitation current and the second excitation current to obtain a measurement signal of the fluxgate current sensor; a PI controller connected between the filtering and demodulation circuit and the input end of the compensation winding, configured to receive the measurement signal and output a feedback current for maintaining zero flux in the fluxgate to the compensation winding; a notch filter connected between the filtering and demodulation circuit and the compensation power supply, configured to obtain a noise value of the excitation frequency of the measurement signal, and use the noise value to control the compensation power supply to output a compensation current with the same frequency, consistent intensity and opposite direction to the compensation winding; The current on the compensation winding is formed by the superposition of the feedback current and the compensation current, and outputs a voltage signal via the load resistor.

3. The suppression device according to claim 1 or 2, characterized in that: When the excitation module is an excitation power supply, the excitation power supply is connected to the first winding and the second winding respectively through a current limiting resistor; then the first excitation current and the second excitation current are both external excitation currents; When the excitation module is a self-excited oscillator, the self-excited oscillator is connected to the first winding and the second winding respectively through a current-limiting resistor and is grounded through a high-precision resistor; then the first excitation current and the second excitation current are both self-excited oscillation currents.

4. The suppression device according to claim 1 or 2, characterized in that: The design performance of the two circular magnetic cores is consistent; The filtering function of the filtering and demodulation circuit is realized by a high-pass filter, a low-pass filter, or a combination of a high-pass filter and a low-pass filter; The PI controller is a digital PI controller or an analog PI controller.

5. A method for suppressing excitation frequency noise of a fluxgate current sensor, characterized in that: The device for suppressing the excitation frequency noise of the fluxgate current sensor according to claim 1 is used to perform the following suppression process: S11, the excitation module generates an excitation current and sends it to the first winding and the second winding, respectively generating a first excitation current and a second excitation current and sending them to the filtering and demodulation circuit respectively; S12, the filtering and demodulation circuit filters the first excitation current and the second excitation current to obtain frequency and phase information, and sends the frequency and phase information as measurement signals of the fluxgate current sensor to the PI controller and the signal acquisition and noise spectrum analysis module respectively; S13, after receiving the measurement signal, the PI controller outputs a feedback current for maintaining zero magnetic flux in the fluxgate; At the same time, the signal acquisition and noise spectrum analysis module converts the measurement signal into a digital signal and then performs noise spectrum analysis to obtain a noise spectrum analysis result of the measurement signal, detects the excitation frequency and noise peak value in the noise spectrum analysis result, and sends the detected excitation frequency and noise peak value to the compensation power supply to control the compensation power supply to output a compensation current with the same frequency, consistent intensity and opposite direction; S14, the feedback current and the compensation current are added to obtain a superimposed current which is fed into the compensation winding. The superimposed current passes through a load resistor to obtain an output voltage signal of a fluxgate current sensor.

6. A method for suppressing excitation frequency noise of a fluxgate current sensor, characterized in that: The device for suppressing the excitation frequency noise of the fluxgate current sensor as claimed in claim 2 is used to perform the following suppression process: S21, the excitation module generates an excitation current and sends it to the first winding and the second winding, respectively generating a first excitation current and a second excitation current and sending them to the filtering and demodulation circuit respectively; S22, the filtering and demodulation circuit filters the first excitation current and the second excitation current to obtain frequency and phase information, and sends the frequency and phase information as measurement signals of the fluxgate current sensor to the PI controller and the notch filter respectively; S23, after receiving the measurement signal, the PI controller outputs a feedback current for maintaining zero magnetic flux in the fluxgate; At the same time, the notch filter obtains the noise value of the excitation frequency of the measurement signal, and uses the noise value to control the compensation power supply to output a compensation current with the same frequency, consistent intensity and opposite direction to the compensation winding; S24, the feedback current and the compensation current are added to obtain a superimposed current which is fed into the compensation winding. The superimposed current passes through a load resistor to obtain an output voltage signal of a fluxgate current sensor.

7. The method of claim 5 or 6, wherein: When the excitation module is an excitation power supply, an AC current source with two channels is used, and the frequencies of the two channels are synchronized, and the phase relationship is kept constant, and the two channels are used as the compensation power supply and the excitation power supply respectively; When the excitation module is a self-excited oscillator, the filtering and demodulation circuit filters the first excitation current and the second excitation current to obtain frequency and phase information, and transmits the frequency and phase information to the compensation power supply.

8. The method of claim 5, wherein: The demodulation circuit adopts a phase-sensitive detection method to obtain the frequency and phase information of the excitation current; the signal acquisition and noise spectrum analysis module obtains the noise spectrum analysis result of the measurement signal by calculating the power spectrum density.

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