A performance evaluation method for fluxgate sensors

Abstract

The invention discloses a performance evaluation method for a fluxgate sensor, which belongs to the technical field of electromagnetic detection. The invention uses a magnetic field generator to generate a magnetic field with linearly varying intensity, and applies excitation signals of multiple frequencies to the sensor to obtain multiple response voltage signals; then, each response voltage signal is divided into early, middle and late sub-signals according to time; then, the voltage difference of each sub-signal is extracted to calculate the voltage instability; then, the voltage change rate is calculated and the voltage change gap value is evaluated based on the voltage change rate; next, according to the early, middle and late voltage change gap values ​​at the same frequency, combined with the enhancement of voltage instability, an evaluation component is obtained; finally, based on the evaluation components at multiple frequencies, the performance evaluation value of the sensor is calculated, thereby improving the accuracy of the performance evaluation of the fluxgate sensor.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic detection technology, and in particular to a performance evaluation method for a fluxgate sensor. Background Art

[0002] In modern industry and technology, fluxgate sensors, as a highly sensitive magnetic field measurement device, are widely used in geophysical exploration, aerospace, medical imaging, industrial detection and other fields. With the rapid development of electronic technology and sensor technology, the performance requirements for fluxgate sensors are getting higher and higher. At present, the traditional performance evaluation method of fluxgate sensors mainly relies on parameter measurement under static magnetic field, which is difficult to fully reflect the actual performance of the sensor under dynamic working conditions. The existing technology usually only focuses on a single indicator of the sensor, such as sensitivity or linearity, and ignores the performance fluctuations and instability that may occur in the sensor at different operating frequencies and time periods. This evaluation method has significant limitations and cannot accurately capture the dynamic response characteristics of the sensor. There is a problem of low accuracy in the performance evaluation of the fluxgate sensor. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, a performance evaluation method for a fluxgate sensor provided by the present invention solves the problem of low performance evaluation accuracy of a fluxgate sensor in the prior art.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is: a performance evaluation method of a fluxgate sensor, comprising the following steps:

[0005] S1. Using a magnetic field generator to generate a magnetic field with linearly varying intensity, applying excitation signals of multiple frequencies to the fluxgate sensor to obtain multiple response voltage signals;

[0006] S2, dividing each response voltage signal according to time to obtain early, middle and late response voltage sub-signals;

[0007] S3, extracting a voltage difference for each response voltage sub-signal to obtain a voltage difference sequence, and calculating a voltage instability based on the voltage difference sequence;

[0008] S4, calculating the voltage change rate for each response voltage sub-signal, and calculating the voltage change gap value based on the voltage change rate;

[0009] S5, according to the voltage change gap values ​​at the early stage, the middle stage and the late stage at the same frequency, based on the enhancement of the voltage instability at the early stage, the middle stage and the late stage, obtaining the evaluation component at the same frequency;

[0010] S6. Calculate a performance evaluation value based on the evaluation components at multiple frequencies.

[0011] Furthermore, S1 comprises the following sub-steps:

[0012] S11, using a magnetic field generator to generate a magnetic field with a linearly varying intensity, applying an excitation signal of a first frequency to the fluxgate sensor, and obtaining a first response voltage signal;

[0013] S12, using a magnetic field generator to generate a magnetic field with a linearly varying intensity, applying an excitation signal of a second frequency to the fluxgate sensor, and obtaining a second response voltage signal;

[0014] S13. Use a magnetic field generator to generate a magnetic field with a linearly varying intensity, apply an excitation signal of a third frequency to the fluxgate sensor, and obtain a third response voltage signal, wherein the third frequency > the second frequency > the first frequency, wherein the difference between the second frequency and the first frequency is less than 100 Hz, and the difference between the third frequency and the second frequency is less than 100 Hz.

[0015] Furthermore, the expression of the magnetic field in S1 is: B(t) = B0+ kt, where B(t) is the magnetic field intensity at time t, B0 is the initial magnetic field intensity, k is the magnetic field change rate, and t is the time number.

[0016] Furthermore, S3 includes the following sub-steps:

[0017] S31. In a response voltage sub-signal, subtract the voltage values ​​at adjacent moments to obtain the voltage difference at each moment: , where v d,t is the voltage difference at time t, v t+1 is the voltage value at time t+1, v t is the voltage value at the tth moment;

[0018] S32, taking the voltage difference at each moment as an element to construct a voltage difference sequence;

[0019] S33. For each voltage difference sequence, calculate the voltage instability.

[0020] Furthermore, the formula for calculating voltage instability in S33 is: , where s is the voltage instability, e is the natural constant, and x i is the i-th element in the voltage difference sequence, N is the number of elements in the voltage difference sequence, i is the number of the element, and || is the absolute value operation.

[0021] Furthermore, the formula for calculating the voltage change rate in S4 is: , where c is the voltage change rate, v t+1 is the voltage value at time t+1, v tis the voltage value at the tth moment, T is the length of the response voltage sub-signal, and △t is the interval time length between the t+1th moment and the tth moment.

[0022] Furthermore, the formula for calculating the voltage change gap value in S4 is: , where c d is the voltage change gap value, e is a natural constant, | | is the absolute value, c is the voltage change rate, c target is the voltage target change rate.

[0023] Further, S5 includes the following sub-steps:

[0024] S51, obtaining a previous enhancement value based on the previous voltage change gap value and the enhancement of the previous voltage instability;

[0025] S52, obtaining a mid-term enhancement value based on the mid-term voltage change gap value and the enhancement of the mid-term voltage instability;

[0026] S53, obtaining a later enhancement value according to the later voltage change gap value and based on the enhancement of the later voltage instability;

[0027] S54. Perform weighted processing on the early enhancement value, the mid-stage enhancement value and the late enhancement value at the same frequency to obtain an evaluation component.

[0028] Furthermore, the enhanced formulas in S51, S52 and S53 are: , where y is the enhancement value, c d is the voltage change difference value, and s is the voltage instability.

[0029] Furthermore, the formula for calculating the performance evaluation value in S6 is: , where X is the performance evaluation value, h j is the evaluation component at the jth frequency, h max is the largest evaluation component, h min is the smallest evaluation component, j is a positive integer from 1 to M, and M is the number of frequencies.

[0030] The beneficial effects of the present invention are:

[0031] 1. The present invention adopts a magnetic field generator to generate a magnetic field with linear intensity variation, tests the induction ability of the fluxgate sensor to the magnetic field with linear intensity variation under excitation signals of various frequencies, and then divides the response voltage signal into detailed stages (early stage, middle stage, and late stage), and calculates the voltage instability and the voltage variation gap value respectively, so as to more accurately quantify the performance fluctuation of the fluxgate sensor in different working stages, and significantly improve the accuracy of performance evaluation.

[0032] 2. The present invention combines the voltage change gap value and voltage instability at different stages under the same frequency to obtain the evaluation component under the frequency, and then combines the evaluation components under multiple frequencies to calculate the performance evaluation value, thereby improving the performance evaluation accuracy of the fluxgate sensor.

[0033] 3. The present invention sets a dynamically changing magnetic field, which facilitates accurate capture of the dynamic response characteristics of the fluxgate sensor and improves the performance evaluation accuracy of the fluxgate sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of a performance evaluation method for a fluxgate sensor;

[0035] Figure 2 is a schematic diagram of a fluxgate sensor;

[0036] Figure 3 Schematic diagram of a magnetic field with linearly varying intensity. DETAILED DESCRIPTION

[0037] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0038] like Figure 1 As shown, a performance evaluation method of a fluxgate sensor includes the following steps:

[0039] S1. Using a magnetic field generator to generate a magnetic field with linearly varying intensity, applying excitation signals of multiple frequencies to the fluxgate sensor to obtain multiple response voltage signals;

[0040] S2, dividing each response voltage signal according to time to obtain early, middle and late response voltage sub-signals;

[0041] S3, extracting a voltage difference for each response voltage sub-signal to obtain a voltage difference sequence, and calculating a voltage instability based on the voltage difference sequence;

[0042] S4, calculating the voltage change rate for each response voltage sub-signal, and calculating the voltage change gap value based on the voltage change rate;

[0043] S5, according to the voltage change gap values ​​at the early stage, the middle stage and the late stage at the same frequency, based on the enhancement of the voltage instability at the early stage, the middle stage and the late stage, obtaining the evaluation component at the same frequency;

[0044] S6. Calculate a performance evaluation value based on the evaluation components at multiple frequencies.

[0045] like Figure 2 As shown, the excitation signal is input into the excitation winding, and the response voltage signal is the signal at the detection winding end.

[0046] In this embodiment, S1 includes the following sub-steps:

[0047] S11, using a magnetic field generator to generate a magnetic field with a linearly varying intensity, applying an excitation signal of a first frequency to the fluxgate sensor, and obtaining a first response voltage signal;

[0048] S12, using a magnetic field generator to generate a magnetic field with a linearly varying intensity, applying an excitation signal of a second frequency to the fluxgate sensor, and obtaining a second response voltage signal;

[0049] S13. Use a magnetic field generator to generate a magnetic field with a linearly varying intensity, apply an excitation signal of a third frequency to the fluxgate sensor, and obtain a third response voltage signal, wherein the third frequency > the second frequency > the first frequency, wherein the difference between the second frequency and the first frequency is less than 100 Hz, and the difference between the third frequency and the second frequency is less than 100 Hz.

[0050] The present invention adopts three kinds of excitation signals of different frequencies to respectively perform three measurements to obtain three corresponding response voltage signals.

[0051] The present invention applies excitation signals of different frequencies to the fluxgate sensor to test the induction of the fluxgate sensor to a magnetic field with linear intensity changes at different frequencies. In the present invention, three similar frequencies are selected to facilitate the evaluation of the stability of the fluxgate sensor at similar frequencies and avoid measurement errors and uncertainties that may be caused by frequency jumps.

[0052] In this embodiment, the first frequency is 5 kHz, the second frequency is 5.05 kHz, and the third frequency is 5.10 kHz. Around 5 kHz is within the operating frequency range of the fluxgate sensor, and a very small frequency interval (50 Hz) is used to achieve accurate evaluation of sensor performance. Since the frequencies are at the same order of magnitude and vary slightly, the measurement deviation that may be introduced by frequency jumps is effectively eliminated.

[0053] In this embodiment, the expression of the magnetic field in S1 is: B(t) = B0+ kt, where B(t) is the magnetic field strength at time t, B0 is the initial magnetic field strength, k is the magnetic field change rate, and t is the time number.

[0054] In this embodiment, k is set to 2μT / s, B0 is 10μT, and B(t) ranges from 10μT to 100μT. Figure 3 shown.

[0055] In this embodiment, when the B(t) range is 10μT~100μT, the test time length is 45S, so the time length of each response voltage signal is 45S, and the response voltage signal is divided into 3 parts, and the lengths of the early, middle and late time periods are 15S. The specific lengths of the early, middle and late time periods can be divided according to needs and are not specifically limited.

[0056] In this embodiment, S3 includes the following sub-steps:

[0057] S31. In a response voltage sub-signal, subtract the voltage values ​​at adjacent moments to obtain the voltage difference at each moment: , where v d,t is the voltage difference at time t, v t+1 is the voltage value at time t+1, v t is the voltage value at the tth moment;

[0058] S32, taking the voltage difference at each moment as an element to construct a voltage difference sequence;

[0059] S33. For each voltage difference sequence, calculate the voltage instability.

[0060] In this embodiment, the formula for calculating the voltage instability in S33 is: , where s is the voltage instability, e is the natural constant, and x i is the i-th element in the voltage difference sequence, N is the number of elements in the voltage difference sequence, i is the number of the element, and || is the absolute value operation.

[0061] Under the condition of linear change of magnetic field intensity, the high-performance fluxgate sensor shows significant linear characteristics of magnetoelectric conversion, and its output voltage signal amplitude shows significant first-order linear correlation with magnetic field intensity, and the induced voltage signal shows a highly linear progressive trend along the magnetic field intensity change trajectory, and the output voltage signal is proportional to the magnetic field intensity, and the induced voltage signal will show approximately linear growth. Therefore, the present invention calculates the voltage difference between adjacent moments, and according to the voltage difference, calculates the instability of the voltage growth change during this period of time, and evaluates its sensitivity and follow-up ability to the magnetic field intensity.

[0062] When voltage instability increases, the output voltage may fluctuate, indicating that the sensor may face response delays or signal distortion in a rapidly changing magnetic field environment. This instability not only affects measurement accuracy, but may also lead to performance degradation in dynamic applications.

[0063] In this embodiment, the formula for calculating the voltage change rate in S4 is: , where c is the voltage change rate, vt+1 is the voltage value at time t+1, v t is the voltage value at the tth moment, T is the length of the response voltage sub-signal, and △t is the interval time length between the t+1th moment and the tth moment.

[0064] In this embodiment, the formula for calculating the voltage change gap value in S4 is: , where c d is the voltage change gap value, e is a natural constant, | | is the absolute value, c is the voltage change rate, c target is the voltage target change rate.

[0065] The present invention sets up a magnetic field with linearly changing intensity. Therefore, in theory, the response voltage signal changes approximately linearly. The present invention calculates the voltage change rate to reflect the slope of the voltage signal, and further analyzes the difference between the change rate and the preset voltage target change rate. When the difference between the voltage change rate and the voltage target change rate is large, it indicates that there is a response lag or low sensitivity to the change of the magnetic field.

[0066] In the present invention, the voltage target change rate is a preset voltage change rate, which represents the ratio of the expected voltage change amount within a given time period to the duration of the time period.

[0067] In this embodiment, S5 includes the following sub-steps:

[0068] S51, obtaining a previous enhancement value based on the previous voltage change gap value and the enhancement of the previous voltage instability;

[0069] S52, obtaining a mid-term enhancement value based on the mid-term voltage change gap value and the enhancement of the mid-term voltage instability;

[0070] S53, obtaining a later enhancement value according to the later voltage change gap value and based on the enhancement of the later voltage instability;

[0071] S54. Perform weighted processing on the early enhancement value, the mid-stage enhancement value and the late enhancement value at the same frequency to obtain an evaluation component.

[0072] The present invention divides each response voltage signal into early, middle and late segments, extracts the voltage change gap value and voltage instability in each segment, realizes time-divided analysis of the response of the fluxgate sensor, and then through weighted processing of different stages, can comprehensively evaluate the overall response capability of the fluxgate sensor at a specific frequency.

[0073] In this embodiment, the enhanced formulas in S51, S52 and S53 are: , where y is the enhancement value, c d is the voltage change difference value, and s is the voltage instability.

[0074] The weighted formula in S54 is: , where h j is the evaluation component at the jth frequency, y j,E is the previous enhancement value at the jth frequency, y j,M is the mid-term enhancement value at the jth frequency, y j,L is the later enhancement value at the jth frequency.

[0075] In this embodiment, the formula for calculating the performance evaluation value in S6 is: , where X is the performance evaluation value, h j is the evaluation component at the jth frequency, h max is the largest evaluation component, h min is the smallest evaluation component, j is a positive integer from 1 to M, and M is the number of frequencies.

[0076] The present invention selects the largest evaluation component and the smallest evaluation component, and calculates the fluctuation coefficient of the evaluation component affected by the frequency. , the frequencies selected in the present invention are similar, The larger the value, the more unstable the fluxgate sensor is in terms of magnetic field induction at different frequencies, and the more unstable it is.

[0077] In the present invention, when the performance evaluation value is larger, the performance of the fluxgate sensor is worse, and when the performance evaluation value is closer to 1, the performance of the fluxgate sensor is better.

[0078] The present invention adopts a magnetic field generator to generate a magnetic field with linearly varying intensity, tests the sensing ability of the fluxgate sensor to the magnetic field with linearly varying intensity under excitation signals of various frequencies, and then divides the response voltage signal into detailed stages (early stage, middle stage, and late stage), and calculates the voltage instability and the voltage change gap value respectively, so as to more accurately quantify the performance fluctuation of the fluxgate sensor in different working stages, and significantly improve the accuracy of performance evaluation.

[0079] The present invention combines the voltage change gap value and voltage instability at different stages under the same frequency to obtain the evaluation component under the frequency, and then combines the evaluation components under multiple frequencies to calculate the performance evaluation value, thereby improving the performance evaluation accuracy of the fluxgate sensor.

[0080] The present invention sets a dynamically changing magnetic field, which is convenient for accurately capturing the dynamic response characteristics of the fluxgate sensor and improving the performance evaluation accuracy of the fluxgate sensor.

[0081] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A performance evaluation method for a fluxgate sensor, characterized in that: The following steps are involved: S1. Using a magnetic field generator to generate a magnetic field with linearly varying intensity, applying excitation signals of multiple frequencies to the fluxgate sensor to obtain multiple response voltage signals; S2, dividing each response voltage signal according to time to obtain early, middle and late response voltage sub-signals; S3. Extract the voltage difference for each response voltage sub-signal to obtain a voltage difference sequence, and calculate the voltage instability based on the voltage difference sequence: , where s is the voltage instability, e is the natural constant, and x i is the i-th element in the voltage difference sequence, N is the number of elements in the voltage difference sequence, i is the number of the element, and || is the absolute value operation; S4. Calculate the voltage change rate for each response voltage sub-signal, and calculate the voltage change gap value based on the voltage change rate: , where c d is the voltage change gap value, c is the voltage change rate, c target is the voltage target change rate; S5. According to the voltage change gap values ​​at the early, middle and late stages under the same frequency, based on the enhancement of the voltage instability at the early, middle and late stages, and weighted processing of the enhanced values ​​at the early, middle and late stages, the evaluation components at the same frequency are obtained, wherein the enhancement formula is: , where y is the enhancement value; S6. Calculate the performance evaluation value based on the evaluation components at multiple frequencies: , where X is the performance evaluation value, h j is the evaluation component at the jth frequency, h max is the largest evaluation component, h min is the smallest evaluation component, j is a positive integer from 1 to M, and M is the number of frequencies.

2. The performance evaluation method of a fluxgate sensor according to claim 1, characterized in that: The S1 comprises the following sub-steps: S11, using a magnetic field generator to generate a magnetic field with linearly varying intensity, applying an excitation signal of a first frequency to the fluxgate sensor, and obtaining a first response voltage signal; S12, using a magnetic field generator to generate a magnetic field with a linearly varying intensity, applying an excitation signal of a second frequency to the fluxgate sensor, and obtaining a second response voltage signal; S13. Use a magnetic field generator to generate a magnetic field with a linearly varying intensity, apply an excitation signal of a third frequency to the fluxgate sensor, and obtain a third response voltage signal, wherein the third frequency > the second frequency > the first frequency, wherein the difference between the second frequency and the first frequency is less than 100 Hz, and the difference between the third frequency and the second frequency is less than 100 Hz.

3. The performance evaluation method of a fluxgate sensor according to claim 1, characterized in that: The expression of the magnetic field in S1 is: B(t) = B0+ kt, where B(t) is the magnetic field strength at time t, B0 is the initial magnetic field strength, k is the magnetic field change rate, and t is the time number.

4. The performance evaluation method of a fluxgate sensor according to claim 1, characterized in that: The S3 comprises the following sub-steps: S31. In a response voltage sub-signal, subtract the voltage values ​​at adjacent moments to obtain the voltage difference at each moment: , where v d,t is the voltage difference at time t, v t+1 is the voltage value at time t+1, v t is the voltage value at the tth moment; S32, taking the voltage difference at each moment as an element to construct a voltage difference sequence; S33. For each voltage difference sequence, calculate the voltage instability.

5. The performance evaluation method of a fluxgate sensor according to claim 1, characterized in that: The formula for calculating the voltage change rate in S4 is: , where c is the voltage change rate, v t+1 is the voltage value at time t+1, v t is the voltage value at the tth moment, T is the length of the response voltage sub-signal, and △t is the interval time length between the t+1th moment and the tth moment.

6. The performance evaluation method of a fluxgate sensor according to claim 1, characterized in that: The S5 comprises the following sub-steps: S51, obtaining a previous enhancement value based on the previous voltage change gap value and the enhancement of the previous voltage instability; S52, obtaining a mid-term enhancement value based on the mid-term voltage change gap value and the enhancement of the mid-term voltage instability; S53, obtaining a later enhancement value according to the later voltage change gap value and based on the enhancement of the later voltage instability; S54. Perform weighted processing on the early enhancement value, the mid-stage enhancement value and the late enhancement value at the same frequency to obtain an evaluation component.

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