Multi-magnetic core fluxgate sensor probe

Abstract

The utility model provides a multi-magnetic-core fluxgate sensor probe, which comprises a plurality of mutually vertical fluxgate sensor sub-probes, and each fluxgate sensor sub-probe comprises an induction framework, an excitation framework and a magnetic core. The induction framework is provided with an inner cavity, and an induction coil is wound on the outer side of the induction framework; the excitation skeletons are arranged in an inner cavity of the induction skeleton in a penetrating mode, the axes of the excitation skeletons are parallel to the axis of the induction skeleton, the excitation skeletons are symmetrically arranged, and an excitation coil is wound around the outer side of each excitation skeleton; and the even number of magnetic cores are respectively arranged in the corresponding excitation frameworks in a penetrating manner.

Description

Technical Field

[0001] This utility model relates to the field of magnetic detection technology, specifically, to a multi-core fluxgate sensor probe. Background Technology

[0002] Fluxgates are among the most sensitive magnetic field elements used to measure magnetic field parameters. There are various types and variations of fluxgates, a typical type being one with dual-core windings and a second harmonic output. The sensitivity of this sensor is directly proportional to the frequency of the excitation magnetic field, the cross-sectional area of ​​the core, the number of turns in the induction coil, the amplitude of the excitation magnetic field, and the characteristic slope. Increasing the number of turns in the induction coil is a common method to improve the sensitivity of the fluxgate. Therefore, a typical high-sensitivity fluxgate magnetometer consists of an excitation coil and an induction coil. To achieve high sensitivity, the induction coil is wound with thousands of turns. This lowers the operating frequency and makes the design more complex. Simultaneously, imperfections in the multi-layer coil winding process lead to increased parasitic capacitance and significant high-frequency noise.

[0003] Therefore, there is an urgent need to develop a multi-core fluxgate sensor probe that can effectively improve sensitivity, reduce high-frequency noise, and reduce the number of coil turns. Utility Model Content

[0004] This invention provides a multi-core fluxgate sensor probe to at least solve the problems of excessive coil turns and significant high-frequency noise in existing high-sensitivity fluxgate sensor probes.

[0005] To achieve the above objectives, this utility model provides a multi-core fluxgate sensor probe, comprising multiple mutually perpendicular fluxgate sensor sub-probes, each fluxgate sensor sub-probe including:

[0006] The induction frame has an inner cavity and an induction coil wound around its outer side;

[0007] An even number of excitation frames are inserted into the inner cavity of the sensing frame. The axis of the excitation frame is parallel to the axis of the sensing frame, and the even number of excitation frames are arranged symmetrically. An excitation coil is wound around the outside of each excitation frame.

[0008] An even number of magnetic cores are respectively inserted into the corresponding excitation frame.

[0009] Furthermore, the excitation coils are connected in series.

[0010] Furthermore, the winding directions of the excitation coils wound on the outer sides of adjacent excitation frames are opposite.

[0011] Furthermore, magnetic flux concentrators are respectively provided on both ends of the induction frame, and the leads of the induction coil and the excitation coil are connected to the magnetic flux concentrators.

[0012] Furthermore, the even number of the excitation frames are fixed together by an insulating adhesive.

[0013] Furthermore, the magnetic core is fixed to the cavity of the excitation frame by an insulating adhesive.

[0014] Furthermore, the magnetic core is made of a cobalt-based amorphous alloy material.

[0015] Furthermore, the coil frame is made of a non-magnetic material.

[0016] Furthermore, the wire diameter of the excitation coil is 0.035mm to 0.1mm, and the wire diameter of the induction coil is 0.05mm to 0.2mm.

[0017] Furthermore, the excitation coil has 200 to 1000 turns, and the induction coil has 100 to 400 turns.

[0018] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0019] This novel multi-core fluxgate sensor probe employs a multi-core symmetrical structure, increasing the effective cross-sectional area of ​​the total magnetic flux and superimposing the magnetic induction intensity, thereby boosting the output signal amplitude by 2-3 times. Simultaneously, the number of coil turns is significantly reduced to 100-400 turns (compared to thousands of turns in traditional structures). This reduces parasitic capacitance and high-frequency noise while solving the problems of manufacturing complexity and limited frequency response caused by excessive coil turns in traditional high-sensitivity fluxgate sensors.

[0020] This utility model's multi-core fluxgate sensor probe expands the linear measurement range of the fluxgate sensor probe in strong magnetic field environments by working in concert with multiple magnetic cores, thus solving the technical problem of easy magnetic saturation of a single magnetic core.

[0021] In this multi-core fluxgate sensor probe, the excitation coils wound around adjacent excitation frames are wound in opposite directions. Through the common-mode noise cancellation principle, external electromagnetic interference and thermal noise are suppressed, effectively improving the signal-to-noise ratio. At the same time, the uniformity of the magnetic field distribution between the cores is optimized, reducing harmonic distortion caused by hysteresis loop asymmetry.

[0022] Furthermore, the multi-core fluxgate sensor probe of this invention compacts the excitation frame within the cavity of the sensing frame, resulting in a compact structure and reduced volume, effectively achieving miniaturization. This makes it suitable for space-constrained applications such as aerospace and precision instruments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the multi-core fluxgate sensor probe structure of this utility model;

[0024] Figure 2 This is a schematic diagram of the structure of a single fluxgate sensor probe of this utility model;

[0025] Figure 3 This is a schematic diagram of the excitation support structure of this utility model;

[0026] Figure 4 This is a voltage-time characteristic curve of the multi-core fluxgate sensor probe of this utility model;

[0027] Figure 5 This is a voltage-time characteristic curve of a traditional dual-core probe.

[0028] In the above image:

[0029] 1. Fluxgate sensor sub-probe; 2. Induction frame; 3. Excitation frame; 4. Magnetic core. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] In the description of this application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "level," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0032] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] Fluxgate sensors, as core components in the field of magnetic field measurement, are widely used in geophysical exploration, aerospace navigation, and industrial inspection due to their superior sensitivity. Traditional fluxgate sensors are typically based on a dual-core winding structure, characterizing magnetic field strength through second harmonic output. Their sensitivity is mainly influenced by factors such as the excitation magnetic field frequency, core cross-sectional area, number of turns in the induction coil, excitation magnetic field amplitude, and the slope of the magnetization curve. To improve sensitivity, current technologies generally employ increasing the number of turns in the induction coil; a typical high-sensitivity fluxgate sensor requires thousands of turns in its induction coil. However, this approach has significant drawbacks:

[0034] Excessive number of turns leads to a significant increase in coil inductance, forcing the operating frequency to drop below kilohertz, making it difficult to meet the requirements of high-frequency magnetic field detection. Multilayer coil winding processes easily introduce problems such as uneven winding gaps and interlayer insulation defects, resulting in a significant increase in parasitic capacitance and consequently high-frequency noise. Thousands of turns of coil require considerable space, and the high-precision winding process drives up manufacturing costs. Furthermore, traditional dual-core structures are prone to losing linearity due to core saturation in strong magnetic field environments, and their insufficient common-mode noise suppression further limits their application range.

[0035] There is an urgent need to provide a new type of fluxgate probe to solve the above problems while ensuring high sensitivity.

[0036] This invention provides a multi-core fluxgate sensor probe, comprising multiple mutually perpendicular fluxgate sensor sub-probes 1, each sub-probe independently detecting magnetic field signals in a specific direction.

[0037] In some embodiments, such as Figure 1 As shown, the multi-core fluxgate sensor sub-probe 1 can include three mutually perpendicular fluxgate sensor sub-probes 1 to achieve the measurement of magnetic field signals in the three directions of X-axis, Y-axis and Z-axis. Through the triaxial orthogonal layout, the probe can simultaneously capture the X / Y / Z components of the spatial magnetic field vector without mechanical rotation or multiple measurements, which significantly improves the detection efficiency.

[0038] In some embodiments, the multi-core fluxgate sensor sub-probe 1 may be adopted as follows: Figure 1 The probe is packaged in the form shown, and the packaged probe has a volume of 24*24*24mm to 40*40*40mm. It has the advantages of compact structure and small size, effectively achieving miniaturization, and can be used in space-constrained scenarios such as aerospace and precision instruments.

[0039] In some embodiments, such as Figures 1-3 As shown, each fluxgate sensor sub-probe 1 includes a sensing frame 2, an excitation frame 3, and a magnetic core 4.

[0040] The sensing frame 2 has an inner cavity and an induction coil wound around its outer side.

[0041] In some embodiments, the sensing frame 2 is a hollow prism shape, having an inner cavity for inserting the excitation frame 3.

[0042] An even number of excitation frames 3 are inserted into the inner cavity of the induction frame 2. The axis of the excitation frame 3 is parallel to the axis of the induction frame 2, and the even number of excitation frames 3 are arranged symmetrically. An excitation coil is wound around the outside of each excitation frame 3.

[0043] In some embodiments, such as Figure 2 As shown, the number of excitation frames 3 can be selected as four, and the four excitation frames 3 are arranged symmetrically, making the magnetic field distribution of the fluxgate sensor sub-probe 1 more uniform. From a spatial structure perspective, they are symmetrically arranged in pairs within the hollow cavity of the sensing frame 2, with the axis of the sensing frame 2 as the center. This symmetrical structure ensures a high degree of consistency in the magnetic field effect on the magnetic core 4 when a current is passed through the excitation coil to generate a magnetic field. With the central axis as the reference, the magnetic fields generated by the excitation frames 3 at relatively different positions superimpose or cancel each other in the region of the magnetic core 4, which can effectively reduce the non-uniformity of the magnetic field distribution, thereby improving the accuracy of the fluxgate sensor in measuring the magnetic field.

[0044] An even number of magnetic cores 4 are respectively inserted into the corresponding excitation frame 3.

[0045] In some embodiments, the hollow portion inside the excitation frame 3 has a shape and size that precisely matches the magnetic core 4. The diameter of the magnetic core 4 is slightly smaller than the inner diameter of the hollow portion of the excitation frame 3, and the gap between them is controlled within a very small range, generally between 0.01-0.05 mm. This design ensures that the magnetic core 4 can be stably installed inside the excitation frame 3 without affecting the coupling effect of the magnetic field due to an excessively large gap, and also avoids difficulties in installing or damage to the magnetic core 4 due to an excessively small gap.

[0046] Preferably, the excitation coils are connected in series.

[0047] In some embodiments, the four excitation coils are connected end to end in sequence. Since the excitation coils are connected in series, the current through each coil is equal, which makes the magnetic field strength generated by each excitation coil highly consistent. In terms of magnetic field superposition, this consistency can ensure that the excitation magnetic field experienced by each magnetic core 4 is uniform. As a result, when the external magnetic field changes, the permeability of each magnetic core 4 changes synchronously, effectively improving the sensor's response accuracy to changes in the magnetic field.

[0048] Preferably, the winding directions of the excitation coils wound on the outer sides of adjacent excitation frames 3 are opposite.

[0049] In some embodiments, during the operation of the magnetic core 4, changes in the external magnetic field cause a change in the permeability of the magnetic core 4. The reverse magnetic field generated by the opposite winding of adjacent excitation coils can enhance the difference in this permeability change, thereby improving the sensor's ability to detect weak magnetic field changes. From the perspective of noise suppression, this design further enhances the common-mode noise cancellation effect. When common-mode signals such as external electromagnetic interference and thermal noise act on the excitation coil, the induced electromotive forces generated by adjacent excitation coils are mutually canceled in the circuit due to their opposite winding directions. This significantly reduces the common-mode noise transmitted to subsequent circuits, effectively improving the sensor's signal-to-noise ratio.

[0050] Preferably, magnetic flux concentrators are provided on both ends of the induction frame 2, and the leads of the induction coil and the excitation coil are connected to the magnetic flux concentrators.

[0051] In some embodiments, the leads of both the induction coil and the excitation coil are connected to a flux concentrator, which optimizes the signal transmission path. The magnetic field generated by the excitation coil is conducted to the induction coil through the magnetic core 4, and the flux concentrator, acting as a connection point, reduces signal loss and interference during transmission. Due to the high permeability of the flux concentrator, it can more effectively couple the magnetic field generated by the excitation coil to the induction coil while reducing magnetic field leakage. This not only improves the energy conversion efficiency of the sensor but also enhances signal stability and reduces the impact of the external environment on signal transmission.

[0052] Preferably, an even number of excitation frames 3 are fixed together by an insulating adhesive.

[0053] In some embodiments, epoxy resin adhesive may be used as the insulating adhesive. Epoxy resin adhesive has good electrical insulation properties, which can effectively prevent leakage between excitation coils, avoid sensor failure due to short circuits, and ensure the electrical safety and stability of the sensor.

[0054] Preferably, the magnetic core 4 is fixed to the cavity of the excitation frame 3 by an insulating adhesive.

[0055] In some embodiments, each individual magnetic core 4 is inserted through the cavity of a single excitation frame 3 and fixed by epoxy resin adhesive.

[0056] Preferably, the magnetic core 4 is made of cobalt-based amorphous alloy material.

[0057] In some embodiments, the magnetic core 4 is made of cobalt-based amorphous alloy material. The magnetic core 4 has a diameter of 100 μm and is cut into a cylindrical shape. This type of material has characteristics such as high permeability and low coercivity. It is easily magnetized by a magnetic field and easily demagnetized. It has a narrow hysteresis loop and extremely low hysteresis loss.

[0058] In some embodiments, the diameter of the magnetic core 4 may be 10–800 μm and the length may be 10–30 mm.

[0059] Preferably, the coil frame is made of a non-magnetic material.

[0060] Preferably, the wire diameter of the excitation coil is 0.035mm to 0.1mm, and the wire diameter of the induction coil is 0.05mm to 0.2mm.

[0061] Preferably, the excitation coil has 200 to 1000 turns, and the induction coil has 100 to 400 turns.

[0062] In some embodiments, the induction coil of a fluxgate sensor in the prior art requires thousands of turns, while in this embodiment, the number of turns of the induction coil is significantly reduced to 100-400 turns. This reduces parasitic capacitance and high-frequency noise, while solving the problems of process complexity and limited frequency response caused by excessive coil turns in traditional high-sensitivity fluxgate sensors.

[0063] In some embodiments, Figure 4 and Figure 5 The figures shown are the voltage-time characteristic curves of the multi-core fluxgate sensor probe of this invention and the voltage-time characteristic curves of a traditional dual-core probe in the prior art. Figures 4-5 As shown, when the control variables are made so that the lengths of the excitation coil and magnetic core 4 are the same and the number of turns of the induction coil is 400, it can be found that the peak voltage of the output signal of the probe of this invention reaches 80mV, while the peak voltage of the traditional dual-core probe is only 24mV. The output signal amplitude of this invention is three times higher than that of the traditional structure.

[0064] The above experimental data fully demonstrate that this invention, through its multi-core symmetrical distribution, reverse-wound series excitation coil, and compact packaging design, significantly outperforms traditional dual-core probes in core performance indicators such as signal amplitude, signal-to-noise ratio, frequency response, and linear range.

[0065] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A multi-core fluxgate sensor probe, comprising multiple mutually perpendicular fluxgate sensor sub-probes, characterized in that, Each fluxgate sensor sub-probe includes: The induction frame has an inner cavity and an induction coil wound around its outer side; An even number of excitation frames are inserted into the inner cavity of the sensing frame. The axis of the excitation frame is parallel to the axis of the sensing frame, and the even number of excitation frames are arranged symmetrically. An excitation coil is wound around the outside of each excitation frame. An even number of magnetic cores are respectively inserted into the corresponding excitation frame.

2. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The excitation coils are connected in series.

3. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The excitation coils wound on the outer sides of adjacent excitation frames are wound in opposite directions.

4. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The induction frame is provided with magnetic flux concentrators on both ends, and the leads of the induction coil and the excitation coil are connected to the magnetic flux concentrators.

5. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The even number of excitation frames are fixed together by insulating adhesive.

6. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The magnetic core is fixed to the cavity of the excitation frame by an insulating adhesive.

7. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The magnetic core is made of cobalt-based amorphous alloy material.

8. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The sensing frame and the excitation frame are made of non-magnetic materials.

9. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The wire diameter of the excitation coil is 0.035mm~0.1mm, and the wire diameter of the induction coil is 0.05mm~0.2mm.

10. The multi-core fluxgate sensor probe according to claim 1, characterized in that, The excitation coil has 200 to 1000 turns, and the induction coil has 100 to 400 turns.

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