Axial lead three-axis broadband magnetic field sensor, preparation method and application method

Abstract

The present invention discloses a direct plug-in three-axis wide-band magnetic field sensor, a preparation method and an application method, belonging to the technical field of magnetic field sensors. A direct plug-in three-axis wide-band magnetic field sensor includes a horizontal substrate and a vertical substrate that are vertically plugged. A magnetoresistive coil combined Wheatstone full-bridge induction circuit that is perpendicular to each other is arranged on the horizontal substrate for detecting the magnetic fields in the X-axis and Y-axis directions. The horizontal substrate is provided with a jack, and the vertical substrate is inserted into the jack and welded to the welding pad. A magnetoresistive coil combined Wheatstone full-bridge induction circuit for detecting the magnetic field in the Z-axis direction is arranged on the vertical substrate. At the same time, a preparation method and an application method based on the above sensor are disclosed. By adopting the above direct plug-in three-axis wide-band magnetic field sensor, preparation method and application method, the magnetoresistive coil combined Wheatstone full-bridge induction circuit is used to expand the magnetic field frequency measurement range of the sensor, which has a high signal-to-noise ratio and a small volume.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic field sensors, and particularly to a direct plug-in type three-axis broadband magnetic field sensor, a preparation method and an application method thereof. Background Art

[0002] A magnetic field sensor is a device that can convert magnetic field changes caused by various changes into electrical signals. With the rapid development of the information industry, industrial automation, transportation, power electronics technology, office automation, household appliances, medical instruments, etc., and the popularization of the application of electronic computers, a large number of sensors are required to convert non-electrical parameters to be measured and controlled into electrical parameter signals that are easy to process.

[0003] Magnetic field sensors are widely used in various magnetic field measurement fields, such as industrial, transportation, consumer electronics, medical, and non-destructive testing fields. In the industrial field, magnetic sensors can be used for the precise measurement of the displacement of various metal parts, the current measurement of large machinery and instruments, the automatic control of industrial systems, the monitoring of currents in power supplies and frequency converters, the energy management of distributed power grids, etc. In the transportation field, magnetic sensors are widely used in systems such as subways, automobiles, ships, airplanes, and high-speed rails. For example, in the subway system, the real-time monitoring and control of the train position and running speed, the automatic control and flexible operation of escalators and elevators in the subway system, and the security access control system in subway stations. In the automotive system, magnetic sensors are used to sense the earth's magnetic field to determine the direction and position of the vehicle, providing accurate navigation information for the driver. Similarly, there are magnetic compasses used in navigation, magnetic heading instruments on airplanes, and the monitoring of speed, vibration, and position information in high-speed rails. In the consumer electronics field, magnetic sensors can be used on various intelligent wearable devices such as game controllers, smart watches, smart phones, and computers for motion detection and direction positioning. In the medical field, magnetic sensors can be used for the current and magnetic field monitoring of large devices such as MRI and CT, and for the monitoring of biological signals such as brain magnetism and muscle magnetism. In the non-destructive testing field, magnetic sensors are used for the consistency analysis of various conductive materials, such as the detection of aircraft skins, the detection of carbon fiber fractures, the detection of metal pipes, and the detection of metal energy storage devices.

[0004] The common three-axis magnetic field sensors in the current market are fluxgate type and chip type. The fluxgate sensor is large in volume, usually discrete, and difficult to be integrated into other systems. The chip-level magnetic field sensors face problems such as small bandwidth and low sensitivity. Among them, the three-axis Hall sensor has very low sensitivity and response frequency, and it is difficult to meet the increasingly high measurement requirements. And due to the manufacturing process problems of the three-axis tunneling magnetoresistance sensor, the z-axis usually has low sensitivity and is easily coupled into magnetic fields in other directions, resulting in measurement errors. This limits the application of the three-axis tunneling magnetoresistance sensor. Summary of the Invention

[0005] The object of the present invention is to provide a direct plug-in three-axis wide-band magnetic field sensor, a preparation method and an application method, so as to solve the above technical problems.

[0006] To achieve the above object, the present invention provides a direct plug-in three-axis wide-band magnetic field sensor, which includes a horizontal substrate and a vertical substrate that are vertically plugged. The horizontal substrate and the vertical substrate are arranged in a housing. A magnetoresistive coil combined Wheatstone full-bridge induction circuit that is perpendicular to each other is arranged on the horizontal substrate for detecting magnetic fields in the X-axis and Y-axis directions. The horizontal substrate is provided with a jack, and welding pads are arranged at the edge of the jack. The plug-in part at the bottom of the vertical substrate is inserted into the jack and welded to the welding pads. A magnetoresistive coil combined Wheatstone full-bridge induction circuit for detecting the Z-axis direction is arranged on the vertical substrate.

[0007] Preferably, the magnetoresistive coil combined Wheatstone full-bridge induction circuit includes a Wheatstone full-bridge structure, magnetoresistors and coils. The magnetoresistors and coils are respectively arranged on two bridge arms of the Wheatstone full-bridge structure, and the impedance parameters of the magnetoresistors and coils are the same.

[0008] Preferably, the magnetoresistive coil combined Wheatstone full-bridge induction circuit includes a Wheatstone full-bridge structure, magnetoresistors and coils. The magnetoresistors and coils are arranged on one of the bridge arms of the Wheatstone full-bridge structure, and the impedance parameters of the magnetoresistors and coils are the same.

[0009] Preferably, the magnetoresistive coil combined Wheatstone full-bridge induction circuit is connected to an instrumentation amplifier to achieve single output.

[0010] Preferably, the magnetoresistive coil combined Wheatstone full-bridge induction circuit is connected to a differential output terminal to achieve differential output.

[0011] Preferably, the plug-in part is provided with welding pads, and the bottom of the vertical substrate is stepped.

[0012] A preparation method for the above-mentioned direct plug-in three-axis wide-band magnetic field sensor is as follows:

[0013] Step S1: Prepare the horizontal substrate and the vertical substrate;

[0014] Step S2: Insert the vertical substrate into the jack of the horizontal substrate and fixedly connect them by welding;

[0015] Step S3: After placing the output pins, put the horizontally and vertically arranged horizontal substrate and vertical substrate into the housing and encapsulate them with glue.

[0016] An application method for the above-mentioned direct plug-in three-axis wide-band magnetic field sensor is as follows:

[0017] The magnetoresistive coil combined Wheatstone full - bridge induction circuit couples the magnetic field to be measured, changes the magnetoresistance and the impedance of the coil, resulting in an unbalanced output of the magnetoresistive coil combined Wheatstone full - bridge induction circuit. The output voltage of the magnetoresistive coil combined Wheatstone full - bridge induction circuit is positively correlated with the magnetic field to be measured.

[0018] Preferably, at zero input, the output of the bridge arm is:

[0019]

[0020] Wherein, X 1 、X 2 、X 3 and X 4 are respectively the element impedances on the four bridge arms of the magnetoresistive coil combined Wheatstone full - bridge induction circuit, and U is the supply voltage of the magnetoresistive coil combined Wheatstone full - bridge induction circuit. When the four element impedances are the same, the output voltage difference V of the bridge arm is equal to 0. If a constant magnetic field is given to make the four element impedances change by ΔX simultaneously and the total impedance of the bridge remains unchanged, and the impedances of the two bridge arms change in opposite directions, the output voltage should be:

[0021]

[0022] Also, since the four element impedances are all X, then at this time:

[0023]

[0024] After simplification, we get:

[0025]

[0026] Therefore, the present invention adopts the above - mentioned one - kind of straight - plug three - axis wide - band magnetic field sensor, preparation method and application method, and has the following beneficial effects:

[0027] (1) The magnetoresistive coil combined Wheatstone full - bridge induction circuit includes a Wheatstone full - bridge structure, a magnetoresistance and a coil. The magnetoresistance and the coil are respectively arranged on two bridge arms of the Wheatstone full - bridge structure or the magnetoresistance and the coil are arranged on one of the bridge arms of the Wheatstone full - bridge structure. The measurement structure combining the magnetoresistance and the coil enables the sensitivity of the sensor to be dominated by the magnetoresistance in the low - frequency band and by the coil in the high - frequency band, thereby expanding the magnetic - field frequency measurement range of the sensor. Moreover, the impedance parameters of the magnetoresistance and the coil are consistent, avoiding the problem of low signal - to - noise ratio of the Z - axis caused by the coating direction limitation during chip - level packaging.

[0028] (2) The horizontal substrate and the vertical substrate are placed and connected by vertical insertion and welded and fixed, so that the sensitive directions of the sensors are perpendicular to each other, thereby reducing the problem of strong crosstalk in the Z-direction channel introduced due to the coating process problem during chip-level packaging. Moreover, the discrete construction method reduces the size of the sensor. The size of the sensor of the present invention is only 15mm x 15mm x 10mm.

[0029] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of the horizontal substrate and the vertical substrate of the present invention;

[0031] Figure 2 It is a schematic circuit diagram of the magnetoresistive coil combined Wheatstone full-bridge induction circuit of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the horizontal substrate of the present invention;

[0033] Figure 4 It is a schematic structural diagram of the vertical substrate of the present invention;

[0034] Figure 5 It is a frequency response curve graph within the passband of the present invention.

[0035] REFERENCE SIGNS

[0036] 1. Horizontal substrate; 11. Jack; 2. Vertical substrate; 21. Insertion part; 3. Welding pad. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The embodiments of the present invention will be described in detail below with reference to the drawings.

[0039] Example 1

[0040] As Figure 1 shown, a vertical plug-in three-axis broadband magnetic field sensor includes a horizontal substrate 1 and a vertical substrate 2 that are vertically plugged. The horizontal substrate 1 and the vertical substrate 2 are arranged inside a housing (not shown in the figure). A magnetoresistive coil combined Wheatstone full-bridge induction circuit is arranged on the horizontal substrate 1. The principle of the magnetoresistive coil combined Wheatstone full-bridge induction circuit is as Figure 2 shown, and it is used to detect the magnetic field in the X-axis and Y-axis directions. As Figure 3 shown, the horizontal substrate 1 is provided with a jack 11, and a welding pad 3 is arranged at the edge of the jack 11. The plug-in part 21 at the bottom of the vertical substrate 2 is inserted into the jack 11 and welded to the welding pad 3. The plug-in part 21 is provided with a welding pad 3. As Figure 4 shown, the bottom of the vertical substrate 2 is stepped, which is beneficial to fixing the vertical substrate 2 to the horizontal substrate 1 and at the same time reducing the influence on the component layout of the horizontal substrate 1. A magnetoresistive coil combined Wheatstone full-bridge induction circuit for detecting the Z-axis direction is arranged on the vertical substrate 2.

[0041] The magnetoresistive coil combined Wheatstone full-bridge induction circuit includes a Wheatstone full-bridge structure, magnetoresistors, and coils. In this embodiment, the magnetoresistors and coils are respectively arranged on two bridge arms of the Wheatstone full-bridge structure, and the impedance parameters of the magnetoresistors and coils are the same. The magnetoresistive coil combined Wheatstone full-bridge induction circuit is connected to an instrumentation amplifier to achieve single output. Or the magnetoresistive coil combined Wheatstone full-bridge induction circuit is connected to a differential output terminal to achieve differential output.

[0042] Example 2

[0043] The magnetoresistive coil combined Wheatstone full-bridge induction circuit includes a Wheatstone full-bridge structure, magnetoresistors, and coils. The magnetoresistors and coils are arranged on one of the bridge arms of the Wheatstone full-bridge structure, and the impedance parameters of the magnetoresistors and coils are the same.

[0044] A preparation method for a vertical plug-in three-axis broadband magnetic field sensor based on the above is as follows:

[0045] Step S1: Prepare the horizontal substrate 1 and the vertical substrate 2.

[0046] Step S2: Insert the vertical substrate 2 into the jack 11 of the horizontal substrate 1 and fixedly connect them by welding.

[0047] Step S3: After placing the output pins, put the horizontally and vertically arranged horizontal substrate 1 and vertical substrate 2 into the housing and encapsulate them with glue.

[0048] An application method of the above-mentioned through-hole type three-axis broadband magnetic field sensor. The magnetoresistive coil combined Wheatstone full-bridge induction circuit couples the magnetic field to be measured, changes the impedance of the magnetoresistor and the coil, resulting in an unbalanced output of the magnetoresistive coil combined Wheatstone full-bridge induction circuit. The output voltage of the magnetoresistive coil combined Wheatstone full-bridge induction circuit is positively correlated with the magnetic field to be measured.

[0049] At zero input, the output of the bridge arm is:

[0050]

[0051] Wherein, X 1 、X 2 、X 3 And X 4 Are the component impedances on the four bridge arms of the magnetoresistive coil combined Wheatstone full-bridge induction circuit respectively, and U is the supply voltage of the magnetoresistive coil combined Wheatstone full-bridge induction circuit. When the four component impedances are the same, the output voltage difference V of the bridge arm is equal to 0. If a constant magnetic field is given to make the four component impedances change by ΔX simultaneously and the total impedance of the bridge remains unchanged, and the impedances of the two bridge arms change in opposite directions, the output voltage should be:

[0052]

[0053] Also, since the four component impedances are the same and all are X, then at this time:

[0054]

[0055] Simplified to:

[0056]

[0057] The sensor made with the above structure is powered by ±5V, forms a differential output through internal configuration, uses a Helmholtz coil to generate a broadband magnetic field of about 40uT in the DC-1MHz range, and uses this sensor for frequency response testing. Its frequency response is as Figure 5 Shown. Finally, it is realized that within DC-1MHz, the sensitivity of the sensor is not less than 20mV / V / uT.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A direct-insertion three-axis wide-band magnetic field sensor, characterized in that: It comprises a horizontal substrate and a vertical substrate which are vertically plugged in. The horizontal substrate and the vertical substrate are arranged in a shell. A mutually perpendicular magnetic resistance coil combined Wheatstone full-bridge induction circuit is arranged on the horizontal substrate for detecting magnetic fields in the X-axis and Y-axis directions. The horizontal substrate is provided with a socket. A welding plate is arranged at the edge of the socket. A plug-in portion at the bottom of the vertical substrate is inserted in the socket and welded to the welding plate. A magnetic resistance coil combined Wheatstone full-bridge induction circuit for detecting the Z-axis direction is arranged on the vertical substrate. The magnetic resistance coil combined Wheatstone full-bridge induction circuit comprises a Wheatstone full-bridge structure, wherein the magnetic resistance and the coil are respectively arranged on two bridge arms of the Wheatstone full-bridge structure, or the magnetic resistance and the coil are arranged on one bridge arm of the Wheatstone full-bridge structure; The magnetoresistive coil combined Wheatstone full-bridge induction circuit couples the magnetic field to be measured, changes the impedance of the magnetic resistance and the coil, and causes an unbalanced output of the magnetoresistive coil combined Wheatstone full-bridge induction circuit. The output voltage of the magnetoresistive coil combined Wheatstone full-bridge induction circuit is positively correlated with the magnetic field to be measured.

2. The direct-insertion three-axis wide-band magnetic field sensor according to claim 1, characterized in that: The magnetic resistance is consistent with the impedance parameter of the coil.

3. The direct-insertion three-axis wide-band magnetic field sensor according to claim 2, characterized in that: The reluctance coil combined Wheatstone full-bridge sensing circuit is connected with an instrumentation amplifier to achieve a single output.

4. The direct-insertion three-axis wide-band magnetic field sensor according to claim 2, characterized in that: The magnetoresistive coil combined Wheatstone full-bridge induction circuit is connected to a differential output terminal to realize differential output.

5. The direct-insertion three-axis wide-band magnetic field sensor according to claim 1, characterized in that: The plug-in part is provided with a welding plate, and the bottom of the vertical base plate is in a stepped shape.

6. A method for preparing a direct-insertion three-axis wide-band magnetic field sensor according to claim 1, characterized in that: The specific steps are as follows: Step S1: preparing a horizontal substrate and a vertical substrate; Step S2: inserting the vertical substrate into the insertion hole of the horizontal substrate and fixing the connection by welding; Step S3: After placing the output pins, the horizontal substrate and the vertical substrate, which are arranged perpendicular to each other, are placed into the outer shell, and are encapsulated by glue filling.

Images