CN115236145B - Device and method for evaluating curing state of glass fiber reinforced material matrix - Google Patents
Device and method for evaluating curing state of glass fiber reinforced material matrix Download PDFInfo
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Abstract
The invention belongs to the field of glass fiber reinforced material matrix curing evaluation, and particularly relates to a device and a method for evaluating the curing state of a glass fiber reinforced material matrix. The device embeds the sensor unit into the target object, and realizes energy exchange and information transmission in an electromagnetic induction mode. By analyzing the returned information, the health detection of non-contact and in-situ structure can be carried out on the target object, and the field monitoring of the curing degree of the glass fiber reinforced material matrix is realized. An apparatus for evaluating the cure status of a glass fiber reinforced material matrix, comprising: a sensor unit and an instrument control end; the sensor unit comprises a receiving coil and an interdigital capacitance sensing unit; the instrument control end comprises a signal generating module, an exciting coil, a current sampling module, an orthogonal phase locking module and a data acquisition and processing module.
Description
Technical Field
The invention belongs to the field of glass fiber reinforced material matrix curing evaluation, and particularly relates to a device and a method for evaluating the curing state of a glass fiber reinforced material matrix.
Background
With the rapid development of the engineering field in China, more and more composite materials are widely applied to the industries such as petrifaction, transportation, construction and the like. For example, in the petroleum industry, storage tanks and pipelines made of glass fiber reinforced materials are exposed outdoors all year round, and the coating layer is exposed to sunlight, rain water, soil acid-base erosion or accidental mechanical impact, so that typical damages such as fiber breakage, cementing layer debonding, layering bubbling and the like easily occur. The damage of the insulating coating layer reduces the capability of the storage tank and the pipeline for resisting the erosion of the external environment, so that the influence of the external environment is deeply applied to the inside of the facility, and the safety long-period continuous service of the storage tank and the pipeline is threatened.
The glass fiber material is generally adopted to repair and reinforce the damaged part aiming at the conventional damage, and the solidification degree of the resin is directly related to the repair strength and the time limit judgment of the in-service structure recovery production, so that the monitoring of the material solidification state is particularly important in the repair process. At the present stage, manual operation is mostly adopted for on-site repair, the curing evaluation is limited by actual operation conditions and the level of operators, and non-contact in-situ monitoring of the internal state of the material is difficult to realize, so that the monitoring of the internal curing degree of the glass fiber composite material by adopting an effective means has important significance.
The traditional glass fiber solidification detection methods include infrared spectroscopy, differential scanning calorimetry, dynamic thermodynamic analysis and the like. However, after further research, the methods all need to manually sample the target material, belong to off-line analysis, and have low field adaptability. The currently available dielectric analysis, optical fiber sensing, ultrasonic wave and on-line detection of the curing degree of materials such as interdigital electrodes have many defects. For example, optical fiber sensing requires embedding an optical fiber in a material and pulling the optical fiber out, and ultrasonic testing has the problem that it is relatively difficult to measure the curing condition at a certain depth inside the material. In addition, in the evaluation of the traditional glass fiber reinforced plastic curing process, the surface hardness is often used as a hook for on-site evaluation index and curing degree; however, when the glass fiber reinforced plastic test piece is thicker, the curing degree of materials at different depths in the structure is also considered to be different.
Therefore, there is a need for a device and a method for evaluating the solidification state of a matrix of a glass fiber reinforced material, which can destroy the original structure of a pipeline and an oil tank without opening holes, occupy small volume and obtain data in a non-contact way.
Disclosure of Invention
The invention provides a device and a method for evaluating the curing state of a glass fiber reinforced material matrix, which embed a sensor unit into a target object to realize energy exchange and information transmission in an electromagnetic induction mode. By analyzing the returned information, the non-contact and in-situ structure health detection can be carried out on the target object, so that the curing degree of the glass fiber reinforced material matrix can be monitored on site.
In order to solve the technical problem, the invention adopts the following technical scheme:
an apparatus for evaluating the cure status of a glass fiber reinforced material matrix, comprising: a sensor unit and an instrument control end; the sensor unit comprises a receiving coil and an interdigital capacitance sensing unit; the instrument control end comprises a signal generating module, an exciting coil, a current sampling module, an orthogonal phase locking module and a data acquisition and processing module;
the receiving coil is prepared and formed by selecting a flexible base and adopting a printing mode, and is embedded into a glass fiber reinforced material matrix to be evaluated;
the exciting coil selects a PCB substrate and is prepared and formed by adopting a printing mode; and the exciting coil is provided with a compensation capacitor and an exciting data input/output port provided with an SMA connector.
Preferably, the current sampling module is composed of a sampling resistor, a current sampling input end with an SMA connector, a current sampling output end with an SMA connector and a current sampling amplifying circuit;
wherein, the sampling resistor adopts a low-order connection method; the SMA connector at the current sampling input end is connected with the SMA connector at the excitation data input/output port of the excitation coil; the current sampling amplifying circuit is formed by connecting a plurality of stages of current sampling operational amplifiers in series, and the operational amplifier in the current sampling amplifying circuit is a TL084 chip.
Preferably, the quadrature phase-locking module is composed of a reference signal processing unit, a detection signal processing unit, a multiplexer and a low-pass filtering unit;
the reference signal processing unit consists of a reference signal input end with an SMA joint, a first reference signal homodromous universal comparator and a second reference signal homodromous universal comparator; one of the first reference signal equidirectional universal comparator and the second reference signal equidirectional universal comparator is provided with a phase shifter; the reference signal input end with the SMA connector is connected with the output end of the signal generation module; the first reference signal same-direction general comparator and the second reference signal same-direction general comparator are chips with models of TL3016 CDR;
the detection signal processing unit consists of a detection signal input end with an SMA joint, a first detection signal voltage follower, a first detection signal homodromous amplifier and a first detection signal reverse amplifier which are connected with the output end of the first detection signal voltage follower, a second detection signal homodromous amplifier and a second detection signal reverse amplifier which are connected with the output end of the second detection signal voltage follower;
the detection signal input end with the SMA connector is connected with the current sampling output end with the SMA connector; the first detection signal equidirectional amplifier, the first detection signal reverse amplifier, the second detection signal equidirectional amplifier and the second detection signal reverse amplifier are chips with the model number of TL 084;
the multiplexer selects a chip with the model number of CD74HC4051M 96;
the low-pass filtering unit comprises a multistage low-pass filtering amplitude amplifier and a low-pass filtering output end with an SMA joint; the low-pass filtering amplitude amplifier is a chip with the model number of TL 084.
In another aspect, the present invention provides a method for evaluating the cure status of a glass fiber reinforced material matrix, comprising the steps of:
s101: preparing a glass fiber reinforced material matrix curing sample to be evaluated, and embedding a receiving coil in a sensor unit into the glass fiber reinforced material matrix curing sample to be evaluated in the preparation process;
s102: fixing an exciting coil at the outer side of a prepared glass fiber reinforced material matrix curing sample to be evaluated, so that the exciting coil and a receiving coil form an exciting matching relationship;
s103: sampling and converting an excitation signal between the receiving coil and the excitation coil to obtain an excitation signal for reflecting the solidification condition of a glass fiber reinforced material matrix solidification sample to be evaluated;
s104: performing amplification quadrature phase locking processing on the excitation signal obtained in the step S103 to obtain a real part voltage signal and an imaginary part voltage signal;
s105: drawing a curve graph of the excitation signal amplitude and time based on the amplitude variation trends of the real part voltage signal and the imaginary part voltage signal obtained in the step S104; the amplitude versus time plot of the excitation signal can be used to assess the cure state of the glass fiber reinforced material matrix.
Preferably, the process of preparing the cured sample of the glass fiber reinforced material matrix to be evaluated in step S101 may be specifically described as follows:
manufacturing a cured sample matrix by using an acrylic plate;
coating the fiber cloth added with the glass fiber reinforced material to be evaluated with epoxy resin which is uniformly stirred;
coating fiber cloth on the surface of the solidified sample substrate, and embedding a receiving coil in the sensor unit;
and continuously coating the fiber cloth added with the glass fiber reinforced material to be evaluated on the fiber cloth to prepare and form a glass fiber reinforced material matrix cured sample to be evaluated.
The invention provides a device and a method for evaluating the curing state of a glass fiber reinforced material matrix, wherein the device for evaluating the curing state of the glass fiber reinforced material matrix comprises a sensor unit and an instrument control end; the sensor unit comprises a receiving coil and an interdigital capacitance sensing unit; the instrument control end comprises a signal generating module, an exciting coil, a current sampling module, an orthogonal phase locking module and a data acquisition and processing module. The device for evaluating the solidification state of the glass fiber reinforced material matrix with the structural characteristics and the evaluation method thereof have at least the following beneficial effects:
(1) The detection precision is high, and the curing state can be displayed in real time.
(2) The non-contact and in-situ detection and evaluation of the solidification state of the glass fiber reinforced material matrix are realized, and the structure to be detected is not required to be damaged for sampling.
(3) The implementation cost is low, and the main body part of the equipment is small.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.
FIG. 1 is a block diagram of an apparatus for evaluating the solidification state of a glass fiber reinforced material matrix according to the present invention;
FIG. 2 is a schematic structural diagram of a receiving coil and an interdigital capacitive sensing unit in an apparatus for evaluating a solidification state of a glass fiber reinforced material matrix according to the present invention;
FIG. 3 is a schematic structural diagram of an excitation data input port of an excitation coil, a compensation capacitor and an excitation data output port of the excitation coil in an apparatus for evaluating a solidification state of a glass fiber reinforced plastic matrix according to the present invention;
FIG. 4 is a schematic diagram of an equivalent circuit model of an apparatus for evaluating a solidification state of a glass fiber reinforced plastic matrix according to the present invention;
FIG. 5 is a simplified circuit model schematic of the equivalent circuit model of FIG. 4;
FIG. 6 is a diagram illustrating the results of simulated semi-resonant impedance point tests performed on the equivalent circuit model and the simplified circuit model shown in FIGS. 4 and 5;
FIG. 7 is a schematic circuit diagram of a current sampling amplifying circuit of a current sampling module in an apparatus for evaluating a solidification state of a glass fiber reinforced plastic matrix according to the present invention;
FIG. 8 is a schematic circuit diagram of a reference signal processing unit of a current sampling module in an apparatus for evaluating a solidification state of a glass fiber reinforced plastic matrix according to the present invention;
FIG. 9 is a schematic circuit diagram of a detection signal processing unit of a current sampling module of an apparatus for evaluating a cured state of a glass fiber reinforced plastic matrix according to the present invention;
FIG. 10 is a schematic circuit diagram of a low pass filter unit of a current sampling module of an apparatus for evaluating a cured state of a glass fiber reinforced plastic matrix according to the present invention;
FIG. 11 is a schematic diagram illustrating an example of a cured sample of a glass fiber reinforced matrix to be evaluated prepared by a method for evaluating a curing state of a glass fiber reinforced matrix according to the present invention
FIG. 12 is a graph of excitation signal amplitude versus time plotted for a method of evaluating a cure state of a glass fiber reinforced material matrix in accordance with the present invention.
Reference numerals: 101. a receiving coil; 102. an interdigital capacitance sensing unit; 103. an excitation coil; 104. a compensation capacitor; 105. an excitation data input port of the excitation coil and an excitation data output port of the excitation coil; 106. manufacturing an acrylic plate into a cured sample matrix; 107. adding fiber cloth of a glass fiber reinforced material to be evaluated; 108. the depth of the glass fiber reinforcement to be evaluated is detected.
Detailed Description
The invention provides a device and a method for evaluating the curing state of a glass fiber reinforced material matrix, which embed a sensor unit into a target object to realize energy exchange and information transmission in an electromagnetic induction mode. By analyzing the returned information, the health detection of non-contact and in-situ structure can be carried out on the target object, so that the curing degree of the glass fiber reinforced material matrix can be monitored on site.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention provides a device for evaluating the curing state of a glass fiber reinforced material matrix, which specifically comprises a sensor unit and an instrument control end as shown in figure 1. The sensor unit further comprises a receiving coil and an interdigital capacitance sensing unit, and the instrument control end comprises a signal generating module, an exciting coil, a current sampling module, an orthogonal phase locking module and a data acquisition and processing module.
As shown in fig. 2, the receiving coil is prepared by printing and is embedded in the matrix of the glass fiber reinforced material to be evaluated. In addition, the receiving coil is also connected with the interdigital capacitance sensing unit. And as shown in fig. 3, the excitation coil is used to complete the excitation process in cooperation with the receiving coil. The exciting coil is prepared by selecting a PCB substrate and adopting a printing mode. The exciting coil is also provided with a compensation capacitor, an exciting data input port of the exciting coil and an exciting data output port of the exciting coil.
It should be noted that, referring to fig. 4, fig. 4 is a schematic diagram of an equivalent circuit model of the apparatus for evaluating the solidification state of the glass fiber reinforced material matrix according to the present invention, which is based on the principle that the half-resonance impedance point changes with the capacitance of the object to be measured. In fig. 4, the circuit units can be explained with reference to the following:
R sample a sampling resistor with low primary side resistance; c X Compensating the system with a capacitor for representing the adjustable impedance characteristic of the excitation end; c L1 To excite the parasitic capacitance of the coil, R L1 To excite the internal resistance of the coil, L 1 An inductance of the exciting coil; l is 2 Receiving coil inductance, R, of a sensor unit on the secondary side L2 To receive the internal resistance of the coil, C L2 Parasitic capacitance of the receiving coil; c sensor Is an interdigital electrode capacitor, R sensor Is interdigital electrode leakage resistance; m is an excitation coil, L 1 And L 2 And (5) mutual inductance.
Notably, the slave system compensates for the capacitance C X When the sensor unit is seen, the equivalent circuit model can be simplified into a port network; furthermore, the resistance value of the sampling resistor is opposite to the voltage source u s The internal resistance (typically 50 Ω), the input impedance is small and therefore negligible; in addition, the capacitance C is compensated based on the system X And a parasitic capacitance C of the exciting coil L1 Are connected in parallel, so that they are combined into C 1_new (ii) a Based on the parasitic capacitance C of the receiving coil L2 And interdigital electrode capacitance C sensor Parallel connection with the same variation trend, and the two capacitors are considered to be combined into C 2_new 。
And, if further neglecting the inter-digital leakage resistance R sensor And the induced voltage is expressed by means of a controlled source, the equivalent circuit model can be simplified as shown in fig. 5, and fig. 5 is a simplified circuit model schematic diagram of the device for evaluating the curing state of the glass fiber reinforced material matrix provided by the invention.
Expressing the simplified circuit model by using phasor representation; wherein,
for phasor representation of the voltage excitation source,
、
、
respectively a phasor representation of the current in each cell,
is a coil
Chinese character Zhong is composed of
The induced voltage that is caused by the voltage drop,
is a coil
Chinese character Zhongyuan
The induced voltage induced. Since the above-described circuit belongs to a planar circuit,can be subjected to mesh analysis, on
The mesh is provided with:
To pair
The mesh is provided with:
To pair
The mesh is provided with:
The above formula (1) -formula (3) is arranged in a matrix form to obtain:
Calculating the reflected impedance of the secondary side to the primary side
By using
To represent
Will be provided with
By using
Represents:
Calculating to obtain equivalent input impedance:
Wherein,
、
are respectively as
And with
Impedance of the mesh around the mesh loop:
Substituting the definition of the coupling coefficient to obtain:
The above equation (10) is an equivalent input impedance expression in the simplified circuit model.
Further, the equivalent circuit model and the simplified circuit model are subjected to simulation tests, and the results of the half-resonant impedance point tests are shown in fig. 6. It can be seen from the equivalent circuit model and the test results that, at the same frequency, when the input capacitance increases, the input impedance mode tends to increase, and thus the curing state (tendency) of the matrix of the glass fiber reinforced material can be evaluated by the evaluation device.
As a preferred embodiment of the present invention, the current sampling module is composed of a sampling resistor, a current sampling input terminal with an SMA connector, a current sampling output terminal with an SMA connector, and a current sampling amplifying circuit; it should be noted that the existing current sampling module has two types, i.e., isolated and non-isolated. The current transformer or the Hall sensor can be used for isolated sampling, and the non-isolated current sampling mainly depends on a sampling resistor, namely, the sampling resistor is connected in series in a loop, so that the current to be sampled flows through the resistor and generates voltage drop at two ends of the resistor; the current in the loop can be converted by measuring the voltage drop across the sampling resistor. Because the exciting coil is insensitive to the grounding, the sampling resistor adopts a low-level grounding method, and the resistance value of the sampling resistor is preferably 100 omega.
In addition, the SMA connector at the current sampling input end is connected with the SMA connector at the excitation data output port of the excitation coil; and as shown in fig. 7, fig. 7 provides a schematic circuit diagram of a current sampling amplifying circuit, where the current sampling amplifying circuit is formed by serially connecting multiple stages of current sampling operational amplifiers (four stages in fig. 7), and an operational amplifier in the current sampling amplifying circuit is a chip with model number TL 084.
As a preferred embodiment of the present invention, the quadrature phase locking module is composed of a reference signal processing unit, a detection signal processing unit, a multiplexer, and a low-pass filtering unit;
as shown in fig. 8, fig. 8 provides a schematic circuit diagram of a reference signal processing unit, where the reference signal processing unit is composed of a reference signal input terminal with an SMA connector, a first reference signal equidirectional general comparator, and a second reference signal equidirectional general comparator; one of the first reference signal equidirectional universal comparator and the second reference signal equidirectional universal comparator is provided with a phase shifter; the reference signal input end with the SMA connector is connected with the output end of the signal generation module; the first reference signal equidirectional universal comparator and the second reference signal equidirectional universal comparator are chips with model numbers of TL3016 CDR.
As shown in fig. 9, fig. 9 provides a circuit schematic diagram of a detection signal processing unit. The detection signal processing unit consists of a detection signal input end with an SMA joint, a first detection signal voltage follower, a first detection signal homodromous amplifier and a first detection signal reverse amplifier which are connected with the output end of the first detection signal voltage follower, a second detection signal homodromous amplifier and a second detection signal reverse amplifier which are connected with the output end of the second detection signal voltage follower;
the detection signal input end with the SMA connector is connected with the current sampling output end with the SMA connector; the first detection signal equidirectional amplifier, the first detection signal reverse amplifier, the second detection signal equidirectional amplifier and the second detection signal reverse amplifier are all chips with the model number of TL 084.
The multiplexer selects a chip with the model number of CD74HC4051M 96.
Fig. 10 provides a circuit schematic diagram of a low pass filter unit, as shown in fig. 10. The low-pass filtering unit comprises a multistage low-pass filtering amplitude amplifier and a low-pass filtering output end with an SMA joint; the low-pass filtering amplitude amplifier is a chip with the model number of TL 084.
It should be added that, in the present invention, the excitation signal of the excitation coil collected by the current sampling module is an alternating current (voltage) signal, the highest frequency of which is about 2MHz, and the excitation signal generated by the excitation coil and the reference signal provided by the signal generating module are processed.
The detection signal processing unit buffers an excitation signal of the excitation coil through a first detection signal voltage follower and a second detection signal voltage follower; and then two groups of input signal pairs with the phase difference of 180 degrees are obtained by the first detection signal homodromous amplifier, the first detection signal reverse amplifier, the second detection signal homodromous amplifier and the second detection signal reverse amplifier. And the reference signal processing unit processes the sinusoidal reference signal provided by the signal generating module into a square wave, and performs analog control on the multiplexer under the action of the phase shifter (for example, phase shifting 90 °), so as to finally process the excitation signal generated by the excitation coil into a direct current voltage signal related to the amplitude and phase of the excitation signal, that is, an alternating current (voltage) signal of the excitation signal is converted into a direct current signal carrying effective information (reflecting the solidification condition of the glass fiber reinforced material matrix to be evaluated).
In another aspect, the present invention provides a method for evaluating the curing status of a glass fiber reinforced material matrix, comprising the steps of:
s101: preparing a glass fiber reinforced material matrix curing sample to be evaluated, and embedding a receiving coil in a sensor unit into the glass fiber reinforced material matrix curing sample to be evaluated in the preparation process.
As a preferred embodiment of the present invention, the process of preparing the cured sample of the glass fiber reinforced material matrix to be evaluated in step S101 may be specifically described as follows:
an acrylic plate was used to make a cured sample matrix. For example: the acrylic plate is manufactured into dies with the length, width and height of 80mm, 60mm and 60mm respectively.
The fiber cloth to which the glass fiber reinforcement to be evaluated was added was coated with epoxy resin which was uniformly stirred.
The surface of the cured sample substrate is coated with a fiber cloth, and a receiving coil in the sensor unit is embedded therein. For example: 20 layers of fiber cloth were coated, with a negligible thickness of about 4 mm.
And continuously coating the fiber cloth added with the glass fiber reinforced material to be evaluated on the fiber cloth to prepare and form a glass fiber reinforced material matrix cured sample to be evaluated. It is added here that the thickness of the fibre cloth coated with the glass fibre reinforcement to be evaluated should correspond to the depth of the glass fibre reinforcement to be evaluated, for example: when it is desired to evaluate the curing of the glass fiber reinforcement at 20mm inside, about 100 layers of the fiber cloth incorporating the glass fiber reinforcement to be evaluated may be applied. Specifically, a cured sample of the glass fiber reinforced material matrix to be evaluated is prepared by referring to the example shown in FIG. 11.
S102: fixing an excitation coil outside the prepared glass fiber reinforced material matrix solidification sample to be evaluated, so that the excitation coil and the receiving coil form an excitation matching relationship;
it is noted that the drive coil may be secured directly above the receiver coil by a gantry to ensure that the drive coil and receiver coil are in a drive-fit relationship.
S103: sampling and converting an excitation signal between the receiving coil and the excitation coil to obtain an excitation signal for reflecting the solidification condition of a glass fiber reinforced material matrix solidification sample to be evaluated;
s104: performing amplification quadrature phase locking processing on the excitation signal obtained in the step S103 to obtain a real part voltage signal and an imaginary part voltage signal;
s105: drawing a curve graph of the excitation signal amplitude and the time based on the amplitude variation trends of the real part voltage signal and the imaginary part voltage signal obtained in the step S104; the amplitude versus time plot of the excitation signal can be used to assess the cure state of the glass fiber reinforced material matrix.
It is to be added that the applicant used a program written by LabVIEW to plot the amplitude of the excitation signal against time; FIG. 11 provides, among other things, a graph of excitation signal amplitude versus time. Referring to FIG. 12, it can be determined that the amplitude increases with increasing cure time during the first 4 hours, indicating that the curing reaction is proceeding; and after 6 hours of curing the amplitude levels off, indicating that the glass fiber reinforcement has substantially cured.
Therefore, the method for evaluating the curing state of the glass fiber reinforced material matrix completes the whole evaluation of the curing state of the glass fiber reinforced material matrix to be evaluated.
The invention provides a device and a method for evaluating the curing state of a glass fiber reinforced material matrix, wherein the device for evaluating the curing state of the glass fiber reinforced material matrix comprises a sensor unit and an instrument control end; the sensor unit comprises a receiving coil and an interdigital capacitance sensing unit; the instrument control end comprises a signal generating module, an exciting coil, a current sampling module, an orthogonal phase locking module and a data acquisition and processing module. The device for evaluating the solidification state of the glass fiber reinforced material matrix with the structural characteristics and the evaluation method thereof have at least the following beneficial effects:
(1) The detection precision is high, and the curing state can be displayed in real time.
(2) The non-contact and in-situ detection and evaluation of the solidification state of the glass fiber reinforced material matrix are realized, and the structure to be detected is not required to be damaged for sampling.
(3) The implementation cost is low, and the main body part of the equipment is small.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and shall cover the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (1)
1. An apparatus for evaluating the cure status of a glass fiber reinforced matrix, comprising: a sensor unit and an instrument control end; the sensor unit comprises a receiving coil and an interdigital capacitance sensing unit; the instrument control end comprises a signal generating module, an exciting coil, a current sampling module, an orthogonal phase locking module and a data acquisition and processing module;
the receiving coil is prepared and formed by selecting a flexible base and adopting a printing mode, and is embedded into a glass fiber reinforced material matrix to be evaluated;
the exciting coil selects a PCB substrate and is prepared and formed by adopting a printing mode; the exciting coil is provided with a compensation capacitor and an exciting data input/output port provided with an SMA joint;
the current sampling module consists of a sampling resistor, a current sampling input end with an SMA joint, a current sampling output end with an SMA joint and a current sampling amplifying circuit;
wherein, the sampling resistor adopts a low-order connection method; the SMA connector at the current sampling input end is connected with the SMA connector at the excitation data input/output port of the excitation coil; the current sampling amplifying circuit is formed by connecting multistage current sampling operational amplifiers in series, and the operational amplifier in the current sampling amplifying circuit selects a chip with the model number of TL 084;
the quadrature phase locking module consists of a reference signal processing unit, a detection signal processing unit, a multiplexer and a low-pass filtering unit;
the reference signal processing unit consists of a reference signal input end with an SMA joint, a first reference signal homodromous universal comparator and a second reference signal homodromous universal comparator; one of the first reference signal equidirectional universal comparator and the second reference signal equidirectional universal comparator is provided with a phase shifter; the reference signal input end with the SMA connector is connected with the output end of the signal generation module; the first reference signal same-direction general comparator and the second reference signal same-direction general comparator are chips with models of TL3016 CDR;
the detection signal processing unit consists of a detection signal input end with an SMA joint, a first detection signal voltage follower, a first detection signal homodromous amplifier and a first detection signal reverse amplifier which are connected with the output end of the first detection signal voltage follower, a second detection signal homodromous amplifier and a second detection signal reverse amplifier which are connected with the output end of the second detection signal voltage follower;
the detection signal input end of the SMA connector is connected with the current sampling output end of the SMA connector; the first detection signal equidirectional amplifier, the first detection signal reverse amplifier, the second detection signal equidirectional amplifier and the second detection signal reverse amplifier are chips with the model number of TL 084;
the multiplexer selects a chip with the model number of CD74HC4051M 96;
the low-pass filtering unit comprises a multistage low-pass filtering amplitude amplifier and a low-pass filtering output end with an SMA joint; the low-pass filtering amplitude amplifier is a chip with the model number of TL 084.
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