Inductive magnetic field sensor multi-resonance-point equivalent circuit model and establishment method

Abstract

The invention provides a multi-resonance-point equivalent circuit model of an induction type magnetic field sensor and an establishment method, the induction type magnetic field sensor comprises an electromagnetic induction assembly, a feedback coil and an amplification circuit, and the multi-resonance-point equivalent circuit model comprises an output end; the RLC equivalent circuit of the electromagnetic induction assembly comprises an equivalent model of a magnetic core and an RLC equivalent circuit coupled with the magnetic core; one end of the equivalent circuit is connected with the RLC equivalent circuit, and the other end of the equivalent circuit is connected with an output end; one end of the equivalent circuit of the negative feedback coil is connected with the output end, and the other end of the equivalent circuit is coupled with the RLC equivalent circuit of the electromagnetic induction assembly; and the at least one parallel resonance equivalent circuit is connected between the RLC equivalent circuit of the electromagnetic induction assembly and the equivalent circuit of the amplification circuit, and is configured to be used for suppressing a resonance peak corresponding to a resonance point in a working frequency band of the sensor.

Description

Technical Field

[0001] The present disclosure relates to the field of electromagnetic technologies, and particularly to an equivalent circuit model with multiple resonance points for an inductive magnetic field sensor and a method for establishing the same. Background Art

[0002] An inductive magnetic field sensor is a sensor that measures magnetic field changes using Faraday's law of electromagnetic induction. It is widely used in fields such as geophysics, medicine, and national defense, and is one of the most common magnetic field sensors. In geophysical electromagnetic method instruments, it is widely used in electromagnetic exploration instruments such as magnetotelluric sounding (MT), controlled-source audio-frequency magnetotelluric sounding (CSAMT), and transient electromagnetic method (TEM). The measurement frequency range covers 0.0001 Hz - 100 kHz, and it is a core component of geophysical electromagnetic equipment. The technology of inductive magnetic field sensors involves a series of technical problems such as the research and development of magnetic cores and the detection of low-frequency weak signals, which is a bottleneck technology hindering the independent research and development of geophysical electromagnetic exploration equipment. In order to optimize the design of inductive magnetic field sensors, it is necessary to establish an equivalent circuit model of the inductive magnetic field sensor. Through simulation calculations of the model, the system function of the inductive magnetic field sensor, that is, the conversion sensitivity (frequency response) of the sensor, can be obtained. Currently, the coil part (including the magnetic core) at the front end of the inductive magnetic field sensor is generally equivalent to a series resonance model of an inductor, a resistor, and a capacitor, and this model has one resonance frequency point. However, in actual situations, there are often more than one resonance frequency point within the sensor bandwidth, so the current equivalent circuit model of the inductive magnetic field sensor is not accurate. Summary of the Invention

[0003] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present disclosure provides an equivalent circuit model with multiple resonance points for an inductive magnetic field sensor and a method for establishing the same.

[0004] To achieve the above object, the technical solution of the present disclosure is as follows:

[0005] According to an embodiment of one aspect of the present disclosure, there is provided an equivalent circuit model with multiple resonance points for an inductive magnetic field sensor. The inductive magnetic field sensor includes an electromagnetic induction component, a feedback coil, and an amplifier circuit. The equivalent circuit model with multiple resonance points includes: an output terminal; an RLC equivalent circuit of the electromagnetic induction component, including an equivalent model of the magnetic core and an RLC equivalent circuit coupled to the magnetic core; an equivalent circuit of the amplifier circuit, one end of which is connected to the RLC equivalent circuit and the other end is connected to the output terminal; an equivalent circuit of the negative feedback coil, one end of which is connected to the output terminal and the other end is coupled to the RLC equivalent circuit of the electromagnetic induction component; and at least one parallel resonance equivalent circuit, which is connected between the RLC equivalent circuit of the electromagnetic induction component and the equivalent circuit of the amplifier circuit and is configured to suppress the resonance peaks corresponding to the resonance points within the working frequency band of the sensor.

[0006] According to an embodiment of the present disclosure, the electromagnetic induction component includes a magnetic core and an induction coil wound around the magnetic core, and the RLC equivalent circuit of the electromagnetic induction component includes an equivalent capacitor C. sc , and an equivalent inductor L and an equivalent resistor R connected in series and connected in parallel across both ends of the capacitor C. sc pc sc .

[0007] According to an embodiment of the present disclosure, a parallel resonance equivalent circuit is introduced based on the resonance point information within the operating frequency band of the magnetic field sensor, and the resonance point information includes the number of resonance peaks and the frequencies of the resonance points corresponding to the respective resonance peaks.

[0008] According to an embodiment of the present disclosure, at least one parallel resonance equivalent circuit can be selectively introduced corresponding to the number of resonance peaks.

[0009] According to an embodiment of the present disclosure, the number of parallel resonance equivalent circuits to be introduced correspondingly is determined based on the number of resonance peaks.

[0010] According to an embodiment of the present disclosure, the parallel resonance equivalent circuit includes an equivalent resonance inductor L, an equivalent resonance resistor R, an equivalent resonance capacitor C, and an equivalent inter-turn capacitor C connected in parallel, where the equivalent resonance resistor R is connected in series with the equivalent resistor R, and the equivalent resonance inductor L is derived from a part of the equivalent inductor L. m m m sm , where the equivalent resonance resistor R is connected in series with the equivalent resistor R, and the equivalent resonance inductor L is derived from a part of the equivalent inductor L. m sc m pc .

[0011] According to an embodiment of the present disclosure, the solution formula for the equivalent resonance capacitor is:

[0012] ;

[0013] The solution formula for the equivalent resonance resistor R m is:

[0014] ;

[0015] Wherein, is the value of the equivalent resonance inductor, is the frequency of the resonance point corresponding to the parallel resonance equivalent circuit, and Q represents the quality factor of the parallel resonance equivalent circuit.

[0016] According to an embodiment of the present disclosure, one end of the equivalent capacitor C sc is grounded, and the other end is connected to the equivalent circuit of the amplifier circuit.

[0017] According to an embodiment of the present disclosure, the equivalent circuit of the negative feedback coil includes a feedback resistor R connected in series in sequence fb , the equivalent inductance L of the negative feedback coil s、 , and the equivalent resistance R of the negative feedback coil s . One end of the equivalent circuit of the negative feedback coil is connected to the output end of the equivalent circuit of the amplifier circuit, and the other end of the equivalent circuit of the negative feedback coil is grounded.

[0018] On the other hand, an embodiment of the present disclosure provides a method for establishing the above-mentioned multi-resonant point equivalent circuit model. The inductive magnetic field sensor includes an electromagnetic induction component, a feedback coil, and an amplifier circuit. The establishment method includes:

[0019] Establish the RLC equivalent circuit of the electromagnetic induction component;

[0020] Establish the equivalent circuit of the amplifier circuit connected to the RLC equivalent circuit;

[0021] Establish the equivalent circuit of the negative feedback coil to complete the establishment of the initial magnetic field sensor equivalent circuit model;

[0022] Confirm the resonant point information within the working frequency band of the magnetic field sensor based on the initial equivalent circuit model; and

[0023] Introduce a parallel resonant equivalent circuit according to the resonant point information to suppress the resonant peak corresponding to the resonant point within the working frequency band of the sensor, and complete the establishment of the multi-resonant point equivalent circuit model of the inductive magnetic field sensor. Description of the Drawings

[0024] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0025] Figure 1 It is a schematic diagram of the single-resonant point equivalent circuit model of the magnetic field sensor.

[0026] Figure 2 It is a schematic diagram of the sensitivity of the coil and the sensitivity of the magnetic field sensor.

[0027] Figure 3 It is a schematic diagram of the multi-resonant point equivalent circuit model of a magnetic field sensor according to an embodiment of the present disclosure.

[0028] Figure 4 It is a schematic diagram of the impedance test structure of the multi-resonant point equivalent circuit model of the magnetic field sensor according to an embodiment of the present disclosure.

[0029] Figure 5a It is a schematic diagram of the multi-resonant point equivalent circuit model of the magnetic field sensor according to an embodiment of the present disclosure.

[0030] Figure 5b Schematic flowchart of the method for establishing the multi-resonance point equivalent circuit model of the magnetic field sensor according to the embodiments of the present disclosure.

[0031] Figure 6 Schematic diagram for comparing the simulation result of the sensitivity of the induced voltage and the actual test result according to the embodiments of the present disclosure.

[0032] Figure 7 Schematic diagram for comparing the simulation and actual test results of the sensitivity of the magnetic field sensor according to the embodiments of the present disclosure. Detailed implementation manners

[0033] The present disclosure provides an inductive magnetic field sensor multi-resonance point equivalent circuit model and a method for establishing the same, introducing a parallel resonance equivalent circuit and combining it with the front-end amplifier circuit model of the sensor to obtain the multi-resonance point equivalent circuit model of the sensor.

[0034] To make the objectives, technical solutions, and advantages of the present disclosure clearer and more understandable, the present disclosure will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0035] In the embodiments of the present disclosure, as shown in Figure 5a and Figure 5b , an inductive magnetic field sensor multi-resonance point equivalent circuit model is provided. The inductive magnetic field sensor includes an electromagnetic induction component, a feedback coil, and an amplifier circuit. The multi-resonance point equivalent circuit model includes:

[0036] An output terminal;

[0037] The RLC equivalent circuit of the electromagnetic induction component, including the equivalent model of the magnetic core and the RLC equivalent circuit coupled to the magnetic core;

[0038] The equivalent circuit of the amplifier circuit, one end of which is connected to the RLC equivalent circuit and the other end is connected to the output terminal;

[0039] The equivalent circuit of the negative feedback coil, one end of which is connected to the output terminal and the other end is coupled to the RLC equivalent circuit of the electromagnetic induction component; and

[0040] At least one parallel resonance equivalent circuit, which is connected between the RLC equivalent circuit of the electromagnetic induction component and the equivalent circuit of the amplifier circuit and is configured to suppress the resonance peaks corresponding to the resonance points within the working frequency band of the sensor.

[0041] According to the embodiments of the present disclosure, the electromagnetic induction component includes a magnetic core and an induction coil wound around the magnetic core. The RLC equivalent circuit of the electromagnetic induction component includes: an equivalent capacitor C sc , and an equivalent inductor L sc connected in series and shunted across both ends of the capacitor C pc and an equivalent resistor Rsc 。

[0042] According to an embodiment of the present disclosure, a parallel resonance equivalent circuit is introduced based on the resonance point information within the operating frequency band of a magnetic field sensor, and the resonance point information includes the number of resonance peaks and the frequencies of the resonance points corresponding to each resonance peak. The number of parallel resonance equivalent circuits to be introduced is determined based on the number of resonance peaks. For example, at least one parallel resonance equivalent circuit can be selectively introduced corresponding to the number of resonance peaks. If there are multiple resonance peaks corresponding to multiple resonance points, one parallel resonance equivalent circuit can be introduced based on the second resonance point, or another parallel resonance equivalent circuit can be introduced based on the third resonance point, or more parallel resonance equivalent circuits can be introduced according to the number of resonance points based on actual requirements, so as to better suppress the resonance peaks within the operating frequency band of the sensor and provide a better equivalent model for describing the sensor within a wider bandwidth.

[0043] According to an embodiment of the present disclosure, as Figure 5a shown, the parallel resonance equivalent circuit ( Figure 5a shown in the red box in m ) includes an equivalent resonance inductor L m , an equivalent resonance resistor R m , an equivalent resonance capacitor C sm , and an equivalent inter-turn capacitor C m , where the equivalent resonance resistor R sc is in series with the equivalent resistor R m . The selection criterion for the value of the equivalent resonance inductor L pc is selected from a part of the equivalent inductor L pc , that is, a small inductor is extracted from the equivalent inductor L pc as the value of the equivalent resonance inductor L m .

[0044] The solution formula for the equivalent resonance capacitor is:

[0045] ;

[0046] The solution formula for the equivalent resonance resistor R m is:

[0047] ;

[0048] Among them, is the value of the equivalent resonance inductor, is the frequency of the resonance point corresponding to the parallel resonance equivalent circuit, and Q represents the quality factor of the parallel resonance equivalent circuit. One end of the equivalent capacitor C sc is grounded, and the other end is connected to the equivalent circuit of the amplifier circuit.

[0049] According to an embodiment of the present disclosure, the equivalent circuit of the negative feedback coil includes a feedback resistor R connected in series in sequence fb , the equivalent inductance L of the negative feedback coil s、 , and the equivalent resistance R of the negative feedback coil s . One end of the equivalent circuit of the negative feedback coil is connected to the output end of the equivalent circuit of the amplifier circuit, and the other end of the equivalent circuit of the negative feedback coil is grounded.

[0050] According to an embodiment of another aspect of the present disclosure, as shown in combination with Figure 5a and Figure 5b , a method for establishing the multi-resonant point equivalent circuit model of the above-mentioned inductive magnetic field sensor is provided. The establishment method includes:

[0051] S1: Establish the RLC equivalent circuit of the electromagnetic induction component;

[0052] S2: Establish the equivalent circuit of the amplifier circuit connected to the RLC equivalent circuit;

[0053] S3: Establish the equivalent circuit of the negative feedback coil to complete the establishment of the initial magnetic field sensor equivalent circuit model;

[0054] S4: Confirm the resonant point information within the working frequency band of the magnetic field sensor based on the initial equivalent circuit model; and

[0055] S5: Introduce a parallel resonant equivalent circuit according to the resonant point information to suppress the resonant peaks corresponding to the resonant points within the working frequency band of the sensor, and complete the establishment of the multi-resonant point equivalent circuit model of the inductive magnetic field sensor.

[0056] The inductive magnetic field sensor (magnetic rod) mainly includes three parts: a magnetic core, a winding coil, and a front-end amplifier circuit. The role of the magnetic core is to enhance the magnetic flux density passing through the coil, and the coil is very sensitive to changes in the ambient magnetic field. The purpose of the amplifier circuit is to amplify the tiny signal induced in the winding so that it can be detected by standard electromagnetic measurement equipment. Generally speaking, the combination of the winding and the magnetic core can be represented as an inductive element with an inherent series resistance, in parallel with a capacitive element. This is the single-resonant point RLC (resistance-inductance-capacitance) series resonant equivalent circuit model of the magnetic field sensor. This model is the basis for understanding the sensitivity of the sensor to magnetic field changes and consists of three key components: a resistor (R), an inductor (L), and a capacitor (C), which jointly determine the resonant characteristics of the sensor.

[0057] The resistance value in this equivalent circuit model corresponds to the direct current (DC) resistance of the coil and can be easily measured using a multimeter. The inductance value can be measured using an impedance analyzer (such as 4294A). In fact, as the frequency increases, the impedance of the coil will change from inductive reactance to capacitive reactance. Therefore, in order to accurately measure the inductance value of the coil, it is best to read the inductance value at a low frequency.

[0058] The determination of the capacitance value is a more complex process because it depends on both the measured inductance value and the resonant frequency points obtained from the impedance analyzer. The resonant frequency is the frequency at which the sensor impedance is the smallest and is a key parameter in the RLC model. By combining the inductance value and the resonant frequency, the capacitance value can be calculated, thus completing the RLC model. This model is crucial for predicting the performance of the sensor and designing circuits that can accurately detect and measure magnetic field changes. In summary, the equivalent circuit model of the magnetic field sensor with flux negative feedback is as Figure 1 shown, where L pc 、R sc and C sc represent the equivalent inductance, resistance, and capacitance of the coil respectively, e represents the induced voltage, V i represents the output voltage of the coil, R fb is the feedback resistor, G represents the equivalent gain of the amplifier, L s and R s represent the equivalent inductance and resistance of the negative feedback coil respectively, M represents the mutual inductance between the induction coil and the negative feedback coil, and V out represents the output of the magnetic field sensor.

[0059] According to Faraday's law, the induced voltage e of the coil can be expressed as:

[0060] ;

[0061] where f represents the frequency, μ app represents the apparent magnetic permeability of the magnetic core, N represents the number of turns of the coil, S represents the cross-sectional area of the magnetic core, and B represents the magnetic flux density. Obviously, the induced voltage is proportional to the frequency.

[0062] According to circuit theory, the output voltage V i of the coil is expressed as:

[0063] (2);

[0064] where ω represents the angular frequency, ω = 2πf.

[0065] According to the solution algorithm of the transfer function in the negative feedback system, it can be obtained that:

[0066] (3);

[0067] (4);

[0068] (5);

[0069] Substituting formulas (1), (4), and (5) into formula (3), the relationship between the output voltage and the input magnetic field can be obtained:

[0070] (6);

[0071] For example, the sensitivity of the induction coil (represented by the dotted-line V i and the sensitivity of the magnetic field sensor (represented by the solid-line V out are shown as Figure 2 shown.

[0072] Obviously, the flux negative feedback can effectively flatten the sensitivity of the magnetic field sensor near the single resonance frequency.

[0073] However, the coil of the magnetic field sensor usually has multiple resonance points (or resonance peaks) within its operating bandwidth. To address this complexity, the traditional series resonance model is extended by introducing a parallel resonance equivalent circuit (or parallel resonance equivalent model), as Figure 3 shown in the red box in. This parallel resonance equivalent circuit introduces additional resistance R m , capacitance C m and inductance L m . The introduction of the parallel resonance equivalent circuit will more comprehensively describe or simulate the magnetic field sensor.

[0074] In the parallel resonance equivalent circuit, a small inductance is extracted from the total inductance of the induction coil as the equivalent resonance inductance , and the equivalent resonance capacitance C m is jointly determined by the second resonance frequency point fm and the value of the equivalent resonance inductance, and the equivalent resonance resistance R m is determined by the Q factor measured at the second resonance point and is usually a relatively large resistance value.

[0075] (7);

[0076] (8);

[0077] To estimate Figure 3 the values of the equivalent components in the equivalent circuit model shown, two steps are required: impedance testing and coil induced voltage testing to achieve the estimation of all parameters.

[0078] 1. Regarding impedance testing:

[0079] Taking the double-resonance coil as an example, the AC impedance test results of the coil obtained using an impedance analyzer (model 4294A) are as Figure 4 shown. The inductance value measured at 40 Hz is denoted as L test, the red dashed line represents the inductor and the blue line represents the resistor. The first resonance peak corresponds to the first resonance frequency of f r1 , and the second resonance peak corresponds to the second resonance frequency of f r2 , then:

[0080] L test =L m +L pc (9);

[0081] (10);

[0082] (11);

[0083] Assume that L m is 10H, and the value of the equivalent inductor L pc can be calculated. In addition, the resistance measured by the impedance analyzer includes the loss of the magnetic core. Therefore, the coil resistance R sc in the model should be determined by the measured value of the DC resistance of the coil. At this time, the parameter values in the double-resonance point model of the magnetic field sensor can be deduced from the impedance test results, as shown in Table 1 below.

[0084] Table 1 Magnetic field sensor parameters

[0085]

[0086] Based on circuit theory and the double-resonance point model, the analytical expression of the induced voltage V i is converted from Equation (2) to Equation (12) as follows:

[0087] (12);

[0088] By substituting the values in Table 1, the sensitivity of the induced voltage can be simulated and calculated. The comparison between the simulation results and the actual results is as Figure 6 shown, Figure 6 where the upper part of the figure shows the sensitivity (amplitude) results and the lower part shows the sensitivity (phase) results. At the same time, a solenoid calibration system is used to measure the sensitivity. The scale factor of the solenoid is 16.934 nT / mA. The frequency scanner in the system is a dynamic signal analyzer (model 35670A).

[0089] It can be observed that the actual measurement results of the magnetic field sensor are basically consistent with the simulation results, indicating that the double-resonance point model is effective.

[0090] 2. Regarding the sensitivity test of the magnetic field sensor:

[0091] By deriving the transfer function of the flux negative feedback magnetic field sensor, it can be observed that Equation (5) remains unchanged, while Equation (4) is revised to Equation (13) as follows:

[0092] (13);

[0093] The expression in Equation (13) can be simplified to:

[0094] (14);

[0095] where the numerator N A :

[0096] (15);

[0097] The denominator DA:

[0098] (16);

[0099] By substituting Equation (13) and Equation (5) into Equation (3) and simplifying the numerator and denominator, the sensitivity of the sensor can be obtained:

[0100] (17);

[0101] Different from considering the input impedance of the device when calculating the induced voltage, here the coil is connected to the amplifier circuit, so the input impedance of the circuit needs to be considered. The input resistance R c of the amplifier circuit is 4 GOhm, and the input capacitance C ca is 200 pF. Obviously, due to the isolation of the circuit, the input parameters of the test equipment do not need to be considered in this scenario.

[0102] In addition, since the sensor as a whole introduces a negative feedback coil, a shielding layer, and a calibration coil, the inter-turn capacitance C cm existing between these coils will increase to 20 pF. The specific parameters are listed in Table 1. Similarly, the comparison between the simulation results and the actual test results of the magnetic field sensor is as Figure 7 shown Figure 7 where the upper part of the figure reflects the sensitivity (amplitude) result, and the lower part of the figure reflects the sensitivity (phase) result.

[0103] Considering the difference between the design and actual implementation of the sensor filter, the test results show that the experiment is consistent with the simulation results. It should be noted that by introducing the parallel resonance equivalent circuit model corresponding to the second resonance point, the fluctuation of the measurement sensitivity of the sensor at 9 kHz is effectively explained.

[0104] As described above, for the dual-resonance model of the magnetic field sensor, its coil parameters can be obtained through impedance analysis tests. By incorporating the parameters of the test equipment and directly connecting the output of the coil to the equipment to measure the sensitivity of the induced voltage, the results are consistent with the simulation. In addition, by integrating the circuit parameters and connecting the coil to the circuit to test the sensitivity of the sensor, the results are also consistent with the simulation results. Therefore, the dual-resonance model of the sensor proposed in this solution has been verified to be correct and effective.

[0105] Currently, the inductive magnetic field sensor has a single resonance point model, and the description of the sensor is incomplete. The multi-resonance point equivalent circuit model and the establishment method of the inductive magnetic field sensor proposed in this disclosure introduce a parallel resonance equivalent circuit of the second resonance point of the coil, which is a component of the magnetic field sensor, thereby explaining the change in the sensitivity of the sensor and effectively expanding the theory of the sensor.

[0106] So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that the implementation manners not shown or described in the drawings or the text of the specification are all forms known to those of ordinary skill in the art and have not been described in detail. In addition, the above definitions of each element and method are not limited to the specific structures, shapes, or manners mentioned in the embodiments, and those of ordinary skill in the art can make simple changes or substitutions to them.

[0107] In addition, in this article, unless otherwise specified, ordinal numbers such as "first" and "second" are only used to distinguish multiple elements with the same name and do not indicate the existence of a rank, hierarchy, execution order, or process order between them. A "first" element and a "second" element may appear in the same component together or in different components separately. The existence of an element with a larger ordinal number does not necessarily mean the existence of another element with a smaller ordinal number.

[0108] In this article, unless otherwise specified, the so-called feature A "or" (or) or "and / or" (and / or) feature B means that A exists alone, B exists alone, or A and B exist simultaneously; the so-called feature A "and" (and) or "and" (and) or "and" (and) feature B means that A and B exist simultaneously; the so-called "including", "comprising", "having", "containing" means including but not limited to this.

[0109] In addition, unless otherwise specifically described or steps that must occur in sequence, the order of the above steps is not limited to those listed above and can be changed or rearranged according to the required design. And the above embodiments can be mixed and used with each other or mixed and used with other embodiments based on considerations of design and reliability, that is, the technical features in different embodiments can be freely combined to form more embodiments.

[0110] The specific embodiments described above further elaborate on the objective, technical solutions, and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not used to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. An equivalent circuit model with multiple resonance points for an inductive magnetic field sensor. The inductive magnetic field sensor includes an electromagnetic induction component, a feedback coil, and an amplification circuit. The equivalent circuit model with multiple resonance points includes: An output terminal; The RLC equivalent circuit of the electromagnetic induction component, including an equivalent model of the magnetic core and an RLC equivalent circuit coupled to the magnetic core; The equivalent circuit of the amplification circuit, with one end connected to the RLC equivalent circuit and the other end connected to the output terminal; The equivalent circuit of the negative feedback coil, with one end connected to the output terminal and the other end coupled to the RLC equivalent circuit of the electromagnetic induction component; And At least one parallel resonance equivalent circuit, connected between the RLC equivalent circuit of the electromagnetic induction component and the equivalent circuit of the amplification circuit and configured to suppress the resonance peaks corresponding to the resonance points within the working frequency band of the sensor.

2. According to the multi-resonant point equivalent circuit model described in claim 1, the electromagnetic induction component includes a magnetic core and an induction coil wound around the magnetic core, and the RLC equivalent circuit of the electromagnetic induction component includes an equivalent capacitance C sc , and an equivalent inductance L sc and an equivalent resistance R pc connected in series and connected in parallel across the two ends of the capacitance C sc .

3. The equivalent circuit model with multiple resonance points according to claim 2, introducing a parallel resonance equivalent circuit based on the resonance point information within the working frequency band of the magnetic field sensor. The resonance point information includes the number of resonance peaks and the frequencies of the resonance points corresponding to each resonance peak.

4. The equivalent circuit model with multiple resonance points according to claim 3, selectively introducing at least one parallel resonance equivalent circuit corresponding to the number of resonance peaks.

5. The equivalent circuit model with multiple resonance points according to claim 3, determining the number of parallel resonance equivalent circuits to be introduced correspondingly based on the number of resonance peaks.

6. According to the multi-resonant point equivalent circuit model described in any one of claims 2-5, the parallel resonant equivalent circuit includes an equivalent resonant inductor L connected in parallel m , an equivalent resonant resistor R m , an equivalent resonant capacitor C m , an equivalent inter-turn capacitor C sm , wherein the equivalent resonant resistor R m is connected in series with the equivalent resistor R sc , and the equivalent resonant inductor L m is derived from a part of the equivalent inductor L pc .

7. The multi-resonant point equivalent circuit model according to claim 6, the equivalent resonant capacitance is solved by the following formula: ； The equivalent resonant resistance R m is calculated by the following formula: ； Among them, is the equivalent resonant inductance value, is the frequency of the resonant point corresponding to the parallel resonant equivalent circuit, and Q represents the quality factor of the parallel resonant equivalent circuit.

8. The multi-resonant point equivalent circuit model according to any one of claims 2-5, wherein one end of the equivalent capacitor C sc is grounded, and the other end is connected to the equivalent circuit of the amplifier circuit.

9. According to the multi-resonant point equivalent circuit model described in any one of claims 2-5, the equivalent circuit of the negative feedback coil includes a feedback resistor R connected in series in sequence fb , the equivalent inductance L of the negative feedback coil s、 , and the equivalent resistance R of the negative feedback coil s , where One end of the equivalent circuit of the negative feedback coil is connected to the output terminal of the equivalent circuit of the amplification circuit, and the other end of the equivalent circuit of the negative feedback coil is grounded.

10. A method for establishing the equivalent circuit model with multiple resonance points according to any one of claims 1-9. The inductive magnetic field sensor includes an electromagnetic induction component, a feedback coil, and an amplification circuit. The establishing method includes: Establishing the RLC equivalent circuit of the electromagnetic induction component; Establishing the equivalent circuit of the amplification circuit connected to the RLC equivalent circuit; Establishing the equivalent circuit of the negative feedback coil to complete the establishment of the initial equivalent circuit model of the magnetic field sensor; Confirming the resonance point information within the working frequency band of the magnetic field sensor based on the initial equivalent circuit model; And Introducing a parallel resonance equivalent circuit according to the resonance point information to suppress the resonance peaks corresponding to the resonance points within the working frequency band of the sensor, and completing the establishment of the equivalent circuit model with multiple resonance points for the inductive magnetic field sensor.

Images