A building block type magnetic isolation frequency division multiplexing soil temperature measuring system and intelligent demodulation method

Abstract

The application relates to the technical field of soil temperature monitoring, in particular to a building block type magnetic isolation frequency division multiplexing soil temperature measuring system and an intelligent demodulation method. The building block type magnetic isolation frequency division multiplexing soil temperature measuring system comprises a standard modular unit, the standard modular unit comprises a temperature measuring building block unit and a relay unit, the temperature measuring building block unit is provided with a first core temperature measuring element and a second core temperature measuring element, the first core temperature measuring element is composed of a magnetic ring primary coil with a fixed number of coil turns, and the first core temperature measuring element is connected to an excitation bus. Through the innovative building block type architecture, the magnetic isolation frequency division multiplexing, the excitation current time division multiplexing based on the Internet of Things, the signal analysis technology of edge computing and cloud computing, the problems of multi-channel signal crosstalk and cross-site multiplexing in a high-temperature environment are effectively solved, and the soil temperature monitoring accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil temperature monitoring, and in particular to a building block type magnetic isolation frequency division multiplexing soil temperature measurement system and an intelligent demodulation method. BACKGROUND

[0002] In oil exploitation, geothermal drilling, contaminated site remediation engineering and other engineering, measuring the temperature of different depths or positions underground is a common requirement. For example, in the in-situ thermal desorption process of contaminated site remediation engineering, the temperature of different depths at different points needs to be monitored in real time according to the process to understand the heating effect.

[0003] The traditional temperature measurement method needs to drill a well for each target depth of each point and bury a sensor. The sensor needs to be prefabricated in the factory, and the customization period is long and the customization cost is high. Usually, only one depth sensor can be buried in a single well. If M depths need to be measured at a point, M wells need to be constructed to place the sensor probes respectively, and then wired respectively, resulting in high construction cost on site. In addition, due to the high customization of the sensor, it cannot be reused by other projects after use in a site, causing resource waste.

[0004] At present, the traditional distributed temperature measurement scheme mainly includes optical fiber temperature measurement system and bus type point sensor network, but both have significant limitations in actual application. Although the optical fiber temperature measurement technology (DTS) is suitable for long distance continuous temperature measurement and has strong anti-electromagnetic interference ability, its deployment flexibility is poor, the optical fiber needs to be laid continuously, and the joint will cause a large signal attenuation, which is difficult to meet the needs of segmented installation, quick disassembly and reuse in the multi-well scene. In addition, the upper limit of the conventional optical fiber temperature measurement is usually not more than 75-100℃, and special optical fiber needs to be used in extreme high temperature environment (such as above 200℃), which is extremely costly. Although the bus type point sensor network (such as thermocouple / platinum resistance system based on CAN, Modbus RS485) has high temperature measurement accuracy, it is limited by the temperature resistance of electronic components (usually only 50-85℃), and only the temperature sensing element can be placed underground, and the rest of the circuit needs to be installed in the wellhead normal temperature zone, resulting in independent wiring for each temperature measurement point, complex wiring and large amount of wire consumption. For example, 6 wires (3 power lines + 3 signal lines) need to be laid when measuring temperature at 3 different depths, and the system deployment needs to be customized according to the specific well depth and the number of measurement points, which cannot realize modularized quick assembly and reuse. At the same time, the high temperature cable connecting the underground probe and the equipment on the wellhead further increases the cost. These traditional schemes are difficult to balance economy, flexibility and reliability in the scenes of multi-well, segmentation, high temperature and quick deployment and reuse. SUMMARY

[0005] The present application overcomes the shortcomings of the prior art and provides a building block type magnetic isolation frequency division multiplexing soil temperature measurement system and an intelligent demodulation method.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a building block type magnetic isolation frequency division multiplexing soil temperature measurement system, which comprises a standard modular unit, the standard modular unit comprising a temperature measurement building block unit and a relay unit:

[0008] The temperature measurement building block unit is provided with a first core temperature measurement element and a second core temperature measurement element, the first core temperature measurement element being composed of a magnetic ring primary coil with a fixed number of turns, and the first core temperature measurement element being connected to an excitation bus;

[0009] The second core temperature measurement element is further divided into a standard capacitor version and a capacitor compensation version according to different design requirements of different use methods, the second core temperature measurement element of the standard capacitor version being connected in series with a thermal sensing resistor through a magnetic ring secondary coil, and the second core temperature measurement element of the capacitor compensation version being connected in series with a thermal sensing resistor independently after the magnetic ring secondary coil and a compensation capacitor are connected in common parallel, wherein the thermal sensing resistor is of PT100 type, and the second core temperature measurement element is connected to a signal bus;

[0010] The temperature measurement building block unit comprises a tail component and a non-tail component, wherein the temperature measurement building block unit of the tail component is usually used as the bottommost temperature measurement module of a soil deep well extension, for temperature measurement at the deepest or farthest position of the end of a soil deep well, and the bottom is designed as a plugging head;

[0011] The relay unit is set as a pure cable transmission module, and the relay unit and the temperature measurement building block unit are used in combination with each other during soil temperature measurement.

[0012] Further, in a preferred embodiment of the present application, the temperature measurement building block unit of the non-tail component is mainly used as an assembly module capable of filtering different modulation signals, and the non-tail component and the tail component are provided with obvious color distinction marks outside, which are used for modular assembly distinction of different temperature measurement building block units.

[0013] Further, in a preferred embodiment of the present application, the excitation bus and the signal bus of the temperature measurement building block unit of the tail component are connected to only one aircraft mother joint at the top end, while the excitation bus and the signal bus of the temperature measurement building block unit of the non-tail component are connected to an aircraft public joint at the top end between temperature measurement units and an aircraft mother joint at the end, and the aircraft public joint and the aircraft mother joint all adopt an IP68 protection level, so that the aircraft joint can transmit an alternating constant current source to the excitation bus and carry mixed modulation signals on the signal bus, and the excitation bus and the signal bus are integrated into two groups of twisted wires.

[0014] Further, in a preferred embodiment of the present application, the standard modular unit is equipped with an external protective sleeve, and the external protective sleeve has the same length as the standard modular unit, the external protective sleeve is made of 304 stainless steel material, and both ends are provided with threaded structures for screwing additional external protective sleeves and conical plugs.

[0015] The second aspect of the application provides an intelligent demodulation method for a building block type magnetic isolation frequency division multiplexing soil temperature measurement system, which is applied to any one of the building block type magnetic isolation frequency division multiplexing soil temperature measurement systems, and specifically includes the following steps:

[0016] At the excitation signal input end, the monitoring response time slots of the target temperature measurement channels are time allocated to generate different sending time nodes, and the cloud and the edge MCU unit write corresponding excitation digital signals to the target temperature measurement channels of the DAC low-frequency function generator at different sending time nodes;

[0017] Each target temperature measurement channel is matched with a power amplifier, and the DAC low-frequency function generator outputs corresponding analog voltages to the power amplifier according to the excitation digital signal, and the power amplifier performs frequency reshaping calculation of power gain on the analog voltage to generate a time sequence heterofrequency band of each target temperature measurement channel at different sending time nodes.

[0018] The wideband current of the time sequence heterofrequency band is input through the excitation bus to excite the magnetic ring chain, at this time, the real-time excitation frequency of the time sequence heterofrequency band to the temperature measurement building block unit is obtained, if the real-time excitation frequency is greater than the tolerance excitation frequency threshold of the temperature measurement building block unit, then the magnetic ring inside the temperature measurement building block unit is calibrated as a first type of frequency division multiplexing magnetic ring; otherwise, it is calibrated as a second type of frequency division multiplexing magnetic ring.

[0019] If the magnetic ring is a first type of frequency division multiplexing magnetic ring, then the impedance condition presented at the unique characteristic frequency when the magnetic ring outputs a specific inductance is analyzed, and according to the analysis result, orthogonal frequency modulation and reference frequency modulation are performed to obtain a standard inductance frequency modulation scheme.

[0020] If the magnetic ring is a second type of frequency division multiplexing magnetic ring, then the sensitivity of the characteristic frequency jump variable output by the random compensation variable calculation of the perturbation compensation capacitor to the random compensation variable is calculated through the power simulation model, and the parameters of the compensation capacitor are analyzed according to the sensitivity coefficient to obtain a capacitor compensation frequency modulation scheme.

[0021] At the signal output end, the temperature measurement signal waveform is acquired after frequency modulation based on the standard inductance frequency modulation scheme and the capacitor compensation frequency modulation scheme, and is directly transmitted to the cloud or the gateway end with the edge computing module through the 4G module.

[0022] The fast Fourier transform algorithm is introduced to identify the temperature measurement signal waveform, and a resonance frequency-signal amplitude mapping table is automatically established. The signal amplitude of each frequency peak point is extracted through the mapping table, and the signal amplitude is inversely analyzed according to the theoretical proportional characteristic of signal amplitude-thermistor-temperature to obtain the dynamic temperature value of the target temperature measurement channel.

[0023] Preferably, the monitoring response time slot of the target temperature measurement channel is time allocated at the excitation signal input end, different sending time nodes are generated, and corresponding excitation digital signals are written to the target temperature measurement channel of the DAC low-frequency function generator at different sending time nodes through the cloud and the edge MCU unit, specifically including the following steps:

[0024] The target temperature measurement channel and the corresponding layout diagram are obtained, the arrival priority of the temperature measurement block unit on different target temperature measurement channels is determined according to the time sequence topology of the layout diagram, and a temperature measurement cutoff topology structure is constructed;

[0025] The time sequence asynchronous characteristics of each target temperature measurement channel are obtained through the temperature measurement cutoff topology structure, the least common multiple of the execution cycle of all target temperature measurement channels is calculated according to the time sequence asynchronous characteristics, and the super-asynchronous cycle of the temperature measurement block unit is obtained;

[0026] In the super-asynchronous cycle, the time is divided into time step slots with a fixed time length span, and a bus sending time slot window of the time step slot is preset. If the conflict rate of the given monitoring response time slot of the target temperature measurement channel embedded in the bus sending time slot window is lower than the preset conflict rate, the target temperature measurement channel is allocated to the time step slot;

[0027] Repeat the embedding step and the conflict analysis step until all target temperature measurement channels are fixedly allocated and designed to generate the sending time nodes of the excitation of different target temperature measurement channels;

[0028] The magnetic ring mutual inductance design drawing of the temperature measurement block unit is obtained, and the magnetic ring characteristic frequency of the temperature measurement block unit deployed on multiple different target temperature measurement channels is extracted through the magnetic ring mutual inductance design drawing;

[0029] According to the frequency template that maintains the maximum approximate matching degree with the magnetic ring characteristic frequency, the corresponding excitation digital signals are written to the target temperature measurement channel of the DAC low-frequency function generator at different sending time nodes through the cloud and the edge MCU unit.

[0030] Preferably, the power amplifier performs frequency reshaping calculation on the power gain of the analog voltage to generate a time sequence heterodyne band of each target temperature measurement channel at different sending time nodes, specifically including the following steps:

[0031] Obtaining the model specification, bandwidth range and distortion decision of the power amplifier, retrieving the power gain-frequency remodeling projection system suitable for the corresponding power amplifier of different channels in the big data network based on the model specification, bandwidth range and distortion decision;

[0032] Based on the power gain-frequency remodeling projection system, constructing the power convolution interleaving rule and the frequency shift register of different sending time nodes, and dividing the excitation digital signal data stream into equal-length signal data blocks;

[0033] According to the convolution interleaving rule, the signal data blocks of different channels are interleaved and inserted into the power gain output along the shift register, at this time the interleaved digital signal data is merged into the communication link of the same DAC low-frequency function generator according to the excitation timing of the sending time node, forming a series of continuous multiplexed frequency signal streams;

[0034] According to a series of said multiplexed frequency signal streams, the corresponding analog voltage is converted and output by the DAC low-frequency function generator and transmitted to the power amplifier, and the interleaving of the continuous multiplexed frequency signal stream is calculated according to the convolution interleaving rule, to shape the frequency sequence of the recovered original signal data, and finally generate the time sequence heterodyne band of each target temperature channel at different sending time nodes.

[0035] Preferably, when the magnetic ring is a type of frequency division multiplexing magnetic ring, the impedance condition presented at the unique characteristic frequency when the magnetic ring outputs a specific inductance is analyzed by a carrier wave, and according to the analysis result, orthogonal frequency modulation and reference frequency modulation are performed to obtain a standard inductance frequency modulation scheme, which specifically includes the following steps:

[0036] If the magnetic ring is a type of frequency division multiplexing magnetic ring, then at this time one or more real-time specific inductances of the type of frequency division multiplexing magnetic ring at the excitation timing in the wide frequency current excitation process are obtained, and the electrodynamics knowledge graph is obtained based on the big data network;

[0037] Each of the real-time specific inductances is identified by the electrodynamics knowledge graph, and a complex carrier encoding worldview for specific inductance membership impedance imaging is output, and the unique characteristic frequency of the type of frequency division multiplexing magnetic ring is obtained;

[0038] A standard carrier spectrum model of the unique characteristic frequency is constructed, the real-time specific inductance is mapped by a carrier impedance using the complex carrier encoding worldview, an impedance complex modulation symbol of each real-time specific inductance is obtained, each of the impedance complex modulation symbols is allocated to a subcarrier sequence segment corresponding to the record in the standard carrier spectrum model according to the excitation timing frequency domain, and the excitation impedance value of the type of frequency division multiplexing magnetic ring at different subcarriers is obtained;

[0039] A minimum impedance threshold at the unique characteristic frequency is preset, if the excitation impedance value is less than the minimum impedance threshold, the reference segment of 0 at the subcarrier position corresponding to the excitation impedance value is calibrated, if the excitation impedance value is less than the minimum impedance threshold, the orthogonal segment of 1 at the subcarrier position is calibrated, and a frequency modulation analysis result is obtained;

[0040] An actual carrier spectrum model of a frequency division multiplexing magnetic ring is obtained, a dislocation degree between the actual carrier spectrum model and a standard carrier spectrum model is calculated, only a model region corresponding to a dislocation degree greater than a preset dislocation degree is extracted, and a main frequency modulation region is marked,

[0041] If the main frequency modulation region is an orthogonal segment displayed as 1, a dislocation-based orthogonal modulation frequency segment is filled for the main frequency modulation region, and if the main frequency modulation region is a reference segment displayed as 0, a fixed reference modulation frequency segment is supplemented for the main frequency modulation region.

[0042] A standard inductance frequency modulation parameter is generated according to the orthogonal modulation frequency segment and the reference modulation frequency segment, and a standard inductance frequency modulation scheme is obtained.

[0043] Preferably, when the magnetic ring is a second type of frequency division multiplexing magnetic ring, a carrier analysis is performed on the impedance condition presented at the unique characteristic frequency when the magnetic ring outputs a specific inductance, and orthogonal frequency modulation and reference frequency modulation are performed according to the analysis result to obtain a standard inductance frequency modulation scheme, which specifically includes the following steps:

[0044] When the magnetic ring is a second type of frequency division multiplexing magnetic ring, the fixed number of turns of the secondary coil of the magnetic ring is obtained according to the unique characteristic frequency of the second type of frequency division multiplexing magnetic ring, and an electric power simulation model of the second type of frequency division multiplexing magnetic ring is constructed through an electrical simulation software.

[0045] The disturbance transfer prior distribution of the second type of frequency division multiplexing magnetic ring is obtained through a large data network search based on the parallel structure of the compensation capacitor, the inductance characteristics under low frequency conditions, and the compensable elements for the fixed number of turns, and a normal compensation disturbance criterion is constructed based on the prior node pattern and parameters of the disturbance transfer prior distribution.

[0046] The Latin hypercube sampling algorithm is introduced, and the disturbance variables of the compensation capacitor in the second type of frequency division multiplexing magnetic ring are sampled based on the normal compensation disturbance criterion in the Latin hypercube sampling algorithm to obtain a random compensation variable matrix of the compensation capacitor.

[0047] The partial derivative formula disturbance is applied by substituting the random compensation variable matrix near the local reference point of the electric power simulation software, and the Sobol contribution index of the random disturbance variable to the characteristic frequency is analyzed in the overall range of the input space of the model to record and obtain the characteristic frequency jump variable of the second type of frequency division multiplexing magnetic ring.

[0048] The sensitivity coefficient threshold is preset based on a unique characteristic frequency, and the sensitivity coefficient is calculated based on a partial derivative and a characteristic frequency jump variable to form a Sobol contribution index for a random disturbance variable;

[0049] If the sensitivity coefficient is greater than the sensitivity coefficient threshold, it indicates that the random compensation variable makes the specific inductance of the second type of frequency division multiplexing magnetic ring at the characteristic frequency reach the minimum impedance with a compensation parameter that is too large, and the compensation capacitor needs to be adjusted in a decreasing manner;

[0050] If the sensitivity coefficient is less than the sensitivity coefficient threshold, it indicates that the random compensation variable makes the specific inductance of the second type of frequency division multiplexing magnetic ring at the characteristic frequency reach the minimum impedance with a compensation parameter that is too small, and the compensation capacitor needs to be adjusted in an increasing manner, thereby generating a capacitor compensation frequency modulation scheme.

[0051] Preferably, the introduced fast Fourier transform algorithm identifies the temperature measurement signal waveform, automatically establishes a resonance frequency-signal amplitude mapping table, extracts the signal amplitude of each frequency peak point through the mapping table, inversely analyzes the signal amplitude according to the theoretical proportional characteristic of signal amplitude-thermistor-temperature, and obtains the dynamic temperature value of the target temperature measurement channel, specifically including the following steps:

[0052] The introduced fast Fourier transform algorithm analyzes the temperature measurement signal waveform, obtains the magnetic ring resonance peak of the target temperature measurement channel, and converts the magnetic ring resonance peak into a sparse vector;

[0053] A Gaussian random matrix is constructed to sample the sparse vector of the magnetic ring resonance peak, and an orthogonal matching pursuit algorithm is introduced in the sampling process to solve and reconstruct the sparse coefficients of the sparse vector, thereby generating a reconstructed frequency spectrum;

[0054] According to the reconstructed frequency spectrum, the signal trend of the magnetic ring resonance peak is automatically identified, a resonance frequency-signal amplitude mapping table is established, and the actual signal amplitude corresponding to different frequency peak points on the magnetic ring resonance peak is extracted through the resonance frequency-signal amplitude mapping table;

[0055] The theoretical proportional characteristic of signal amplitude-thermistor-temperature is obtained, the actual signal amplitude is inversely calculated according to the theoretical proportional characteristic, a residual vector of the temperature generated by the actual signal amplitude driving the thermistor and a Jacobian matrix of temperature fluctuation are generated, the theoretical proportional damping factor is adjusted in combination with the residual vector and the Jacobian matrix, and the temperature state of the iterative thermistor is updated in this way, thereby deriving the current residual sum of squares;

[0056] If the current residual sum of squares is gradient growth compared with the preset residual sum of squares, the temperature index corresponding to the current residual sum of squares is replaced with the proportional temperature corresponding to the actual signal amplitude;

[0057] If the current residual sum of squares is compared with the preset residual sum of squares and appears to be gradient descent, the update process is ignored, and the final output target temperature channel reaches the dynamic temperature value at each frequency peak point.

[0058] The beneficial technical effects of the present application are:

[0059] The present application is modularly designed for industry general requirements, and the product can be used out of the box, quickly assembled on site, saving factory customization time and customization cost. The internal components and external protective sleeves are in the form of building blocks and are used separately. Even if the external sleeve is damaged during disassembly, the internal components can still be reused at the next site, achieving material recycling, and the unified length of the modular components facilitates transportation and management, promoting resource recycling. Secondly, based on the distributed temperature measurement of thermal resistance, multiple standard units can be connected in series for a single well to achieve rapid temperature measurement at multiple points, reducing the workload of on-site drilling construction. On the one hand, the input end combines the Internet of Things solution, and sends time-sharing instructions from the cloud to the frequency transmission module through 4G, realizing time-sharing multiplexing of a single channel and further saving costs. On the other hand, the output end combines the Internet of Things solution, directly transmits the signal to the edge computing end of the cloud or gateway, and uses the fast Fourier transform algorithm for waveform analysis, which greatly reduces the cost of on-site construction compared to traditional solutions. BRIEF DESCRIPTION OF DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings of embodiments according to these drawings without creative labor.

[0061] Figure 1 It is a whole structure schematic diagram of the temperature measurement building block unit of the non-tail assembly;

[0062] Figure 2 It is a whole structure schematic diagram of the temperature measurement building block unit of the non-tail assembly;

[0063] Figure 3 It is a whole structure schematic diagram of the temperature measurement building block unit of the non-tail assembly;

[0064] Figure 4 It is a whole structure schematic diagram of the temperature measurement building block unit of the non-tail assembly;

[0065] Figure 5 It is a whole structure schematic diagram of the temperature measurement building block unit of the non-tail assembly;

[0066] Figure 6 It is a whole structure schematic diagram of the temperature measurement building block unit of the non-tail assembly;

[0067] Figure 7 Fig. 1 is a schematic diagram of the overall structure of an external protective sleeve;

[0068] Figure 8 Fig. 2 is a schematic diagram of the overall structure of a first core temperature measuring element;

[0069] Figure 9 Fig. 3 is a schematic diagram of the overall structure of a second core temperature measuring element (standard inductance version);

[0070] Figure 10 Fig. 4 is a schematic diagram of the overall structure of a second core temperature measuring element (compensation capacitor version).

[0071] The reference signs are explained as follows:

[0072] 101, temperature measuring block unit; 102, first core temperature measuring element; 103, second core temperature measuring element; 104, magnetic ring primary coil; 105, excitation bus; 106, magnetic ring secondary coil; 107, thermal sensing resistor; 108, compensation capacitor; 109, signal bus; 201, tail assembly; 202, non-tail assembly; 203, aircraft male joint; 204, aircraft female joint; 205, twisted pair; 206, external protective sleeve; 207, conical plug; 208, plugging head; 209, threaded structure. DETAILED DESCRIPTION

[0073] In order to enable a person skilled in the art to better understand the above-mentioned objects, features and advantages of the present application, the present application will be further described in detail below in conjunction with the drawings and specific embodiments, which are all simplified schematic diagrams and only show the basic structure of the present application in a schematic manner, and therefore only show the components related to the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0074] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms “center”, “longitudinal”, “transverse”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application. In addition, the terms “first”, “second” and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with “first”, “second” and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of “a plurality of” is two or more.

[0075] In the description of the application, it is necessary to explain that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood through specific circumstances.

[0076] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0077] As Figures 1-10 shown, the first aspect of the present application provides a building block type magnetic isolation frequency division multiplexing soil temperature measurement system, comprising a standard modular unit, the standard modular unit comprising a temperature measurement building block unit 101 and a relay unit.

[0078] The temperature measurement building block unit 101 is provided with a first core temperature measurement element 102 and a second core temperature measurement element 103, the first core temperature measurement element 102 is composed of a fixed number of turns of magnetic ring primary coil 104, and the first core temperature measurement element 102 is connected to the excitation bus 105.

[0079] The second core temperature measurement element 103 is divided into standard capacitor version and capacitor compensation version according to the design requirements of different use methods, the second core temperature measurement element 103 of the standard capacitor version is connected in series with the thermal sensing resistor 107 through the magnetic ring secondary coil 106, and the second core temperature measurement element 103 of the capacitor compensation version is connected in series with the thermal sensing resistor 107 independently after the magnetic ring secondary coil 106 and the compensation capacitor 108 are connected in common parallel, wherein the thermal sensing resistor 107 adopts PT100 model, and the second core temperature measurement element 103 is connected to the signal bus 109.

[0080] It should be noted that the control excitation signal input end sends the excitation signal, the excitation signal is transmitted along the excitation bus 105 to the magnetic ring primary coil 104 of the first core temperature measuring element 102, at this time the magnetic ring primary coil 104 generates an induced magnetic field, the induced magnetic field passes through the magnetic ring secondary coil 106 of the second core temperature measuring element 103 to generate a frequency waveform matched with the characteristic frequency, the frequency waveform signal enters the thermal sensing resistance 107 of PT100 type, the signal amplitude of the magnetic ring secondary coil 106 reaches the peak value, and the resistance value of the thermal resistance 107 at the temperature forms a temperature measurement signal waveform which is transmitted to the signal output end through the signal bus 109 to analyze the temperature value, complete the monitoring of the soil temperature, realize the distributed temperature measurement based on thermal resistance and the magnetic ring resonance principle, can make a single monitoring well connected with multiple standard units, construct the frequency and amplitude distribution of different temperature measuring points, achieve the effect of multi-point temperature rapid determination and feedback, greatly reduce the on-site drilling construction workload, save manpower and material resources. And by selecting a high-temperature-resistant magnetic ring, temperature measurement in an extremely high-temperature environment (200℃-500℃) can be realized.

[0081] The temperature measuring building block unit 101 includes a tail assembly 201 and a non-tail assembly 202, wherein the tail assembly 201 of the temperature measuring building block unit 101 is usually used as the bottommost temperature measuring module of the soil deep well extension, for temperature measurement at the deepest or farthest end of the soil deep well, and the bottom is designed as a plugging head 208.

[0082] The temperature measuring building block unit 101 of the non-tail assembly 202 is mainly used as an assembly module that can filter different modulation signals, and the non-tail assembly 202 and the tail assembly 201 are externally provided with obvious color distinction marks, which are used for modular assembly distinction of different temperature measuring building block units 101.

[0083] The excitation bus 105 and the signal bus 109 of the temperature measuring building block unit 101 of the tail assembly 201 are only connected with an aircraft carrier joint 203 at the top end, while the excitation bus 105 and the signal bus 109 of the temperature measuring building block unit 101 of the non-tail assembly 202 are connected with an aircraft public joint 204 at the top end between the temperature measuring units 101, and connected with an aircraft carrier joint 203 at the end. The aircraft public joint 204 and the aircraft carrier joint 203 both adopt IP68 protection level, so that the aircraft joint can transmit alternating constant current source to the excitation bus 105 and carry mixed modulation signal on the signal bus 109, and the excitation bus 105 and the signal bus 109 are integrated into two groups of twisted wires 205.

[0084] It should be noted that before monitoring the soil temperature, a well head of a specified depth is dug at the target temperature measurement point, and a suitable number of temperature measurement block units of the tail assembly 201 and the non-tail assembly 202 are selected according to the monitoring depth, for example, three non-tail assemblies 202 of 1 meter in length and one tail assembly 201 of 1 meter in length are selected for monitoring a 4-meter-long monitoring well. The male aviation connector 204 of the first non-tail assembly 202 is butted against the female aviation connector 203 of the second non-tail assembly 202, and the male aviation connector 204 of the second non-tail assembly 202 is butted against the female aviation connector 203 of the third non-tail assembly 202, and so on until the temperature measurement block units of all non-tail assemblies 202 are spliced. Finally, the female aviation connector 203 of the temperature measurement block unit of the tail assembly 201 is connected to the male aviation connector 204 of the Nth non-tail assembly 202 to form a block splicing type soil temperature measurement structure in which the temperature measurement block units of the N non-tail assemblies 202 serve as the measurement channel and the temperature measurement block unit of the tail assembly 201 serves as the end of the channel. Based on the block concept, the present application constructs a segmented temperature measurement kit that can be quickly connected, realizes temperature measurement requirements for any site, quickly assembles a distributed temperature measurement system, saves the process of factory customization, and can be quickly removed and reused in other sites after use.

[0085] The relay unit is a pure cable transmission module, which is used in combination with the temperature measurement block unit 101 during soil temperature measurement.

[0086] The standard modular unit is matched with an external protective sleeve 206, and the length of the external protective sleeve 206 is the same as that of the standard modular unit. The external protective sleeve 206 is made of 304 stainless steel, and both ends are provided with a threaded structure 209 for screwing additional external protective sleeves 206 and a conical plug 207.

[0087] It should be noted that after the butt joint of each standard modular unit is completed, it is placed in the external protective sleeve 206. One standard modular unit corresponds to one external protective sleeve 206, and each external protective sleeve 206 is connected to each other through the threaded structure 209 at both ends, and the conical plug 207 is connected to the last threaded structure 209 of the last external protective sleeve 206, realizing temperature measurement protection of the standard modular unit. The internal elements and the external protective sleeve 206 are both block splicing type and are used separately. Even if the external protective sleeve 206 is damaged during disassembly, the internal elements can still be reused in the next site, realizing material recycling, and the unified length of the modular assembly facilitates transportation and management, promoting resource recycling.

[0088] It should be noted that the aviation joint adopts a foolproof design to ensure accurate connection. For different industries, the length (L) of the standard modular unit should not be too long, and the length of 1 meter is preferred in the pollution site to meet the needs of convenient transportation, storage management and the like, and promote recycling and reuse.

[0089] The second aspect of the application provides an intelligent demodulation method for a building block type magnetic isolation frequency division multiplexing soil temperature measurement system, which is applied to any one of the building block type magnetic isolation frequency division multiplexing soil temperature measurement systems, and specifically includes the following steps:

[0090] At the excitation signal input end, the monitoring response time slots of the target temperature measurement channels are time allocated to generate different sending time nodes, and the cloud and the edge MCU unit write corresponding excitation digital signals to the target temperature measurement channels of the DAC low-frequency function generator at different sending time nodes;

[0091] Each target temperature measurement channel is matched with a power amplifier, and the DAC low-frequency function generator outputs corresponding analog voltages to the power amplifier according to the excitation digital signal, and the power amplifier performs frequency reshaping calculation of power gain on the analog voltage to generate a time sequence heterofrequency band of each target temperature measurement channel at different sending time nodes.

[0092] The wideband current of the time sequence heterofrequency band is input through the excitation bus to excite the magnetic ring chain, at this time, the real-time excitation frequency of the time sequence heterofrequency band to the temperature measurement building block unit is obtained, if the real-time excitation frequency is greater than the tolerance excitation frequency threshold of the temperature measurement building block unit, then the magnetic ring inside the temperature measurement building block unit is calibrated as a first type of frequency division multiplexing magnetic ring, otherwise, it is calibrated as a second type of frequency division multiplexing magnetic ring.

[0093] If the magnetic ring is a first type of frequency division multiplexing magnetic ring, then the impedance condition presented at the only characteristic frequency when the magnetic ring outputs a specific inductance is analyzed, and according to the analysis result, orthogonal frequency modulation and reference frequency modulation are performed to obtain a standard inductance frequency modulation scheme.

[0094] If the magnetic ring is a second type of frequency division multiplexing magnetic ring, then the sensitivity of the characteristic frequency jump variable output by the random compensation variable calculation of the perturbation compensation capacitor to the random compensation variable is calculated through the power simulation model, and the parameter of the compensation capacitor is analyzed according to the sensitivity coefficient to obtain a capacitor compensation frequency modulation scheme.

[0095] At the signal output end, the temperature measurement signal waveform is acquired after frequency modulation based on the standard inductance frequency modulation scheme and the capacitor compensation frequency modulation scheme, and is directly transmitted to the cloud or the gateway end with the edge computing module through the 4G module.

[0096] The fast Fourier transform algorithm is introduced to identify the temperature measurement signal waveform, and a resonance frequency-signal amplitude mapping table is automatically established.

[0097] Preferably, the monitoring response time slot of the target temperature measurement channel is time allocated at the excitation signal input end, different sending time nodes are generated, and corresponding excitation digital signals are written to the target temperature measurement channel of the DAC low-frequency function generator at different sending time nodes through the cloud and edge MCU unit.

[0098] Obtain the target temperature measurement channel and the corresponding layout diagram, and construct the temperature measurement cutoff topology structure according to the arrival priority of the temperature measurement block unit on different target temperature measurement channels in the layout diagram.

[0099] Obtain the time sequence asynchronous characteristics of each target temperature measurement channel through the temperature measurement cutoff topology structure, calculate the least common multiple of the execution of all target temperature measurement channels according to the time sequence asynchronous characteristics, and obtain the super-asynchronous period of the temperature measurement block unit.

[0100] Divide the time into time step slots with fixed time length span in the super-asynchronous period, preset the bus sending time slot window of the time step slot, and if the conflict rate of the predetermined monitoring response time slot of the target temperature measurement channel embedded in the bus sending time slot window is lower than the preset conflict rate, the target temperature measurement channel is allocated to the time step slot.

[0101] Repeat the embedding step and the conflict analysis step until all target temperature measurement channels are fixedly allocated and designed to generate the sending time nodes of the excitation of different target temperature measurement channels.

[0102] Obtain the magnetic ring mutual inductance design of the temperature measurement block unit, and extract the magnetic ring characteristic frequency of the temperature measurement block unit deployed on multiple different target temperature measurement channels through the magnetic ring mutual inductance design.

[0103] According to the frequency paradigm that maintains the maximum approximate matching degree with the magnetic ring characteristic frequency, write corresponding excitation digital signals to the target temperature measurement channel of the DAC low-frequency function generator at different sending time nodes through the cloud and edge MCU unit.

[0104] It should be noted that the temperature measurement cutoff topology is a priority level established according to the depth distribution pattern of the soil temperature measurement point, for example, deeper soil temperature measurement point may need more priority timing signal input. The temperature measurement cutoff topology reflects the asynchronous difference of the excitation cycle between the target temperature measurement channels at the timing signal cutoff node, that is, the timing asynchronous feature. The period misalignment revealed by the timing asynchronous feature further determines the length of the excitation cycle period of the target temperature measurement channel, and the superasynchronous period of each temperature measurement block unit is determined, forming a unified time frame. In this framework, the timing of all target temperature measurement channels can be repeatedly arranged, providing a repeatable time allocation reference for channel multiplexing. Then, according to the superasynchronous period, the time is divided into a series of fixed-length time slices, that is, time step slots. Each time step slot is a timing execution unit of the target temperature measurement channel. Therefore, a bus transmission time slot window is preset for it, so as to avoid the overlap of excitation time between channels, and make the time of sending channel 1-N instructions of the DAC low-frequency function generator of the cloud or edge MCU more discrete and controllable. If the conflict rate of the predetermined monitoring response time slot of the target temperature measurement channel embedded in the bus transmission time slot window is higher than the preset conflict rate, it means that the response time slot of the target temperature measurement channel conflicts with the bus access, which may cause interference between excitation signals of different channels. Therefore, the target temperature measurement channel with a conflict rate lower than the preset conflict rate is allocated to the corresponding time step slot, until all target temperature measurement channels are fixedly allocated, which can effectively guarantee the time determinacy of the excitation bus instruction transmission, further help to distinguish different frequency waveforms, and realize reliable channel time multiplexing effect of soil temperature measurement.

[0105] It should be noted that the series of frequency waveforms generated by the excitation signal input end need to be matched with the magnetic ring design of the temperature measurement block unit. For this purpose, the method generates excitation digital signals to the DAC low-frequency function generator at the frequency template where the magnetic ring characteristic frequency is maximally matched, so that the excitation input of soil temperature measurement is more accurate, and the excitation oscillation effect of frequency waveform is reduced.

[0106] Preferably, the power amplifier performs frequency reshaping calculation of power gain of analog voltage to generate timing heterodyne band of each target temperature measurement channel at different transmission time nodes, specifically including the following steps:

[0107] The model specification, bandwidth range and distortion decision of the power amplifier are obtained, and the power gain-frequency reshaping projection system suitable for different channel corresponding power amplifier is retrieved and obtained in the big data network based on the model specification, bandwidth range and distortion decision;

[0108] The power gain-frequency remodeling projection system is used to remodel and project the frequency structure of the input analog voltage signal according to the power gain change of the power amplifier, and provides a reference benchmark for analyzing the target frequency components after power amplification. The convolution interleaving rule provides a reliable basis for the interleaved insertion of signal data blocks, so that adjacent analog voltage signal data is dispersed when outputting the power amplifier, for example, the data block of the first channel does not follow the next block of the first channel, but is inserted at different times. The frequency shift register is used to temporarily store the signal data block according to the transmission time sequence; and the signal data blocks of different channels are interleaved and inserted along the shift register and output with power gain, so that adjacent frequency symbols of the analog voltage signal data are no longer continuously present in the output stream, but are dispersed at different transmission times, which makes the continuous burst interference in the channel only damage individual frequency waveform symbols after dispersion, rather than a whole segment of continuous symbols, effectively diluting the interference error into a small amount of error in different channels or different time positions, ensuring the accuracy of the frequency waveform description of the analog voltage converted after power amplification, and minimizing signal interference. The finally generated time sequence heterodyne band is a different frequency waveform at different time sequences, realizing time division multiplexing of a single channel.

[0109] According to the convolution interleaving rule, the signal data blocks of different channels are interleaved and inserted along the shift register and output with power gain, at this time the interleaved analog voltage signal data is combined into the communication link of the same DAC low-frequency function generator according to the excitation timing of the transmission time node, forming a series of continuous multiplexed frequency signal streams;

[0110] According to the convolution interleaving rule, the signal data blocks of different channels are interleaved and inserted along the shift register and output with power gain, at this time the interleaved analog voltage signal data is combined into the communication link of the same DAC low-frequency function generator according to the excitation timing of the transmission time node, forming a series of continuous multiplexed frequency signal streams;

[0111] It should be noted that the power gain-frequency remodeling projection system is used to remodel and project the frequency structure of the input analog voltage signal according to the power gain change of the power amplifier, and provides a reference benchmark for analyzing the target frequency components after power amplification. The convolution interleaving rule provides a reliable basis for the interleaved insertion of signal data blocks, so that adjacent analog voltage signal data is dispersed when outputting the power amplifier, for example, the data block of the first channel does not follow the next block of the first channel, but is inserted at different times. The frequency shift register is used to temporarily store the signal data block according to the transmission time sequence; and the signal data blocks of different channels are interleaved and inserted along the shift register and output with power gain, so that adjacent frequency symbols of the analog voltage signal data are no longer continuously present in the output stream, but are dispersed at different transmission times, which makes the continuous burst interference in the channel only damage individual frequency waveform symbols after dispersion, rather than a whole segment of continuous symbols, effectively diluting the interference error into a small amount of error in different channels or different time positions, ensuring the accuracy of the frequency waveform description of the analog voltage converted after power amplification, and minimizing signal interference. The finally generated time sequence heterodyne band is a different frequency waveform at different time sequences, realizing time division multiplexing of a single channel.

[0112] Preferably, when the magnetic ring is a frequency division multiplexing magnetic ring, the impedance condition presented at the only characteristic frequency when the magnetic ring outputs a specific inductance is analyzed, and the standard inductance frequency modulation scheme is obtained according to the analysis result, which specifically includes the following steps:

[0113] If the magnetic ring is a frequency division multiplexing magnetic ring, then one or more real-time specific inductances of the frequency division multiplexing magnetic ring at the excitation timing in the wide frequency current excitation process are obtained, and the electrodynamics knowledge graph is obtained based on the big data network.

[0114] Each of the real-time specific inductance is identified through the electrics knowledge graph, a complex carrier coding world view for specific inductance belonging impedance imaging is output, and a unique characteristic frequency of a type of frequency division multiplexing magnetic ring is obtained;

[0115] A standard carrier spectrum model of the unique characteristic frequency is constructed, the real-time specific inductance is mapped to carrier impedance by using the complex carrier coding world view, an impedance complex modulation symbol of each real-time specific inductance is obtained, each of the impedance complex modulation symbols is distributed to a subcarrier sequence fragment recorded in the standard carrier spectrum model according to an excitation time sequence frequency domain, and an excitation impedance value of the type of frequency division multiplexing magnetic ring located on different subcarriers is obtained;

[0116] A minimum impedance threshold at the unique characteristic frequency is preset, if the excitation impedance value is less than the minimum impedance threshold, a reference segment of 0 at a subcarrier position corresponding to the excitation impedance value is marked, if the excitation impedance value is less than the minimum impedance threshold, a quadrature segment of 1 at the subcarrier position is marked, and a frequency modulation analysis result is obtained;

[0117] An actual carrier spectrum model of the type of frequency division multiplexing magnetic ring is obtained, a dislocation degree between the actual carrier spectrum model and the standard carrier spectrum model is calculated, only a model region corresponding to a preset dislocation degree is extracted, and the model region is marked as a main frequency modulation region,

[0118] If the main frequency modulation region is a quadrature segment displayed as 1, a quadrature modulation frequency segment based on the dislocation degree is filled in the main frequency modulation region, if the main frequency modulation region is a reference segment displayed as 0, a fixed reference modulation frequency segment is supplemented in the main frequency modulation region;

[0119] A standard inductance frequency modulation parameter is generated according to the quadrature modulation frequency segment and the reference modulation frequency segment, and a standard inductance frequency modulation scheme is obtained.

[0120] It should be noted that in each temperature measurement unit, the magnetic ring as an independent current transformer corresponds to a unique characteristic frequency. Therefore, when the excitation frequency is high (MHz level), it is recommended to use this scheme. Because the wideband current input by the excitation bus excites the nth magnetic ring due to its specific inductance, it will present the minimum impedance at the characteristic frequency. Therefore, this method obtains the unique characteristic frequency of a class of frequency division multiplexing magnetic rings, and establishes a standard carrier spectrum model of the unique characteristic frequency, which provides a standardized template and fitting carrier for impedance fitting under the condition of achieving real-time specific inductance for a class of frequency division multiplexing magnetic rings. At the same time, through the identification of the electrical knowledge graph, the complex carrier coding world view for the impedance imaging of specific inductance membership is obtained, which is used to describe the impedance characteristics generated under different specific inductance conditions in the form of complex coding on the carrier. The complex coding database and rules are accurately defined. Further, according to the complex carrier coding world view, the real-time specific inductance is mapped to the carrier impedance to generate the corresponding impedance complex modulation symbol, which expresses the complex impedance summary of the nth magnetic ring at the characteristic frequency when it reaches the specific inductance. Then, according to the excitation timing frequency domain, these impedance complex modulation symbols are distributed to the standard carrier spectrum model position, so as to realize the actual excitation impedance matching of the frequency carrier, that is, the excitation impedance value. If the excitation impedance value is less than the minimum impedance threshold, it indicates that the specific inductance generated by the magnetic ring at this time can maintain the unique characteristic frequency, so it is not necessary to adjust or appropriately fine-tune the inductance frequency, and therefore the reference segment of 0 is calibrated on the subcarrier position corresponding to the excitation impedance value. The corresponding formula is:

[0121] ,

[0122] wherein, is the unique characteristic frequency, is the specific inductance, is the compensation capacitor.

[0123] If it is less than, it indicates that the standard resonance of the magnetic ring cannot be achieved, so it is necessary to adjust the inductance frequency to ensure that the unique characteristic frequency is achieved, and therefore the orthogonal segment of 1 is calibrated on the subcarrier position. Based on the magnetic ring resonance principle and frequency division multiplexing, this method constructs the frequency and amplitude distribution graph of different temperature measurement points, so that the temperature measurement building block unit realizes segmented modularization, saves resources, and enables segmented rapid building block assembly.

[0124] In addition, when the standard inductive frequency modulation scheme is adopted, the frequency selection unit comprises a magnetic coupling component which establishes the characteristic frequency through the turn ratio of the primary coil and the secondary coil. Considering power frequency crosstalk and frequency band separation, the magnetic ring frequency band should meet the following requirements: the turn number of the primary coil of a type of frequency division multiplexing magnetic ring is a fixed value, and the turn number of the secondary coil is a series value; the theoretical inductance and the theoretical resonance frequency are calculated according to the turn number of the secondary coil in turn, and the specific calculation formula is:

[0125] ,

[0126] Wherein, M is the turn number of the secondary coil of the magnetic ring, and M∈[1, 50] is preferred.

[0127] Subsequently, the quality factor Q of each type of frequency division multiplexing magnetic ring at different temperatures is determined by laboratory measurement, and the maximum change coefficient ω of Q at room temperature and at extreme high temperature is obtained. The specific formula is:

[0128] ,

[0129] Wherein, is the quality factor at room temperature (25℃), is the quality factor at extreme high temperature.

[0130] Further, the theoretical width of each frequency band is calculated, and the specific formula is:

[0131] ,

[0132] In order to ensure the frequency band isolation at extreme temperature, the excitation frequency point interval should meet the following two frequency band isolation constraints:

[0133] ,

[0134] ,

[0135] Wherein, is the maximum bandwidth of all magnetic rings at room temperature.

[0136] Finally, according to the theoretical bandwidth requirement, the magnetic ring specifications that meet the requirements can be screened to form a product series of a type of frequency division multiplexing magnetic ring.

[0137] Preferably, when the magnetic ring is a type II frequency division multiplexing magnetic ring, the impedance condition presented at the only characteristic frequency when the magnetic ring outputs a specific inductance is analyzed by carrier wave, and according to the analysis result, the orthogonal frequency modulation and the reference frequency modulation are performed to obtain the standard inductive frequency modulation scheme, which specifically includes the following steps:

[0138] If the magnetic ring is a two-type frequency division multiplexing magnetic ring, then the fixed number of turns of the secondary coil of the magnetic ring is obtained according to the unique characteristic frequency of the two-type frequency division multiplexing magnetic ring, and an electrical simulation model of the two-type frequency division multiplexing magnetic ring is constructed through electrical simulation software;

[0139] The disturbance transfer prior distribution of the two-type frequency division multiplexing magnetic ring is obtained through the parallel configuration of the compensation capacitor, the inductance characteristics under low frequency conditions, and the compensable elements for fixed turns, and the normal compensation disturbance criterion is constructed based on the prior node pattern and parameters of the disturbance transfer prior distribution;

[0140] The Latin hypercube sampling algorithm is introduced, and the disturbance variables of the compensation capacitor in the two-type frequency division multiplexing magnetic ring are sampled based on the normal compensation disturbance criterion in the Latin hypercube sampling algorithm to obtain a random compensation variable matrix of the compensation capacitor;

[0141] The partial derivative formula disturbance is applied by substituting the random compensation variable matrix near the local reference point of the electrical simulation software, and the Sobol contribution index of the random disturbance variable to the characteristic frequency is analyzed in the overall range of the input space of the model to record and obtain the characteristic frequency jump variable of the two-type frequency division multiplexing magnetic ring;

[0142] Based on the preset sensitivity coefficient threshold of the unique characteristic frequency, the sensitivity coefficient of the Sobol contribution index of the random disturbance variable to the characteristic frequency jump variable is calculated based on the partial derivative;

[0143] If the sensitivity coefficient is greater than the sensitivity coefficient threshold, it means that the random compensation variable makes the specific inductance of the two-type frequency division multiplexing magnetic ring at the characteristic frequency reach the minimum impedance compensation parameter too large, and the compensation capacitor needs to be adjusted by decreasing;

[0144] If the sensitivity coefficient is less than the sensitivity coefficient threshold, it means that the random compensation variable makes the specific inductance of the two-type frequency division multiplexing magnetic ring at the characteristic frequency reach the minimum impedance compensation parameter too small, and the compensation capacitor needs to be adjusted by increasing, thereby generating a capacitor compensation frequency modulation scheme.

[0145] It should be noted that when the excitation frequency is low (kHz level or Hz level), the present scheme is recommended. At low frequency, due to the small distributed capacitance, a very large inductance is required, which will result in a very large number of turns of the magnetic ring coil (possibly thousands of turns), which is beyond the range of normal coil production. In this case, the present method constructs a power simulation model of the second type of frequency division multiplexing magnetic ring, and according to the parallel structure of the compensation capacitor, the inductance characteristics under the condition of low frequency and the compensation elements for fixed turns, the disturbance transfer prior distribution of the second type of frequency division multiplexing magnetic ring is obtained, which is the probability estimation distribution pattern of how much the compensation capacitor will require the transfer parameter when the inductance required to reach the fixed turns. The prior node pattern and parameter are reasonable prior value guidelines that are realistic and highly representative, so further random sampling of disturbance variables is carried out based on the normal compensation disturbance criterion to obtain the random compensation variable matrix of the compensation capacitor. Then, the present method uses the random compensation variables in the random compensation variable matrix to apply local perturbations, i.e. partial derivative perturbations, to the corresponding power simulation software, simulates the further observation of the global contribution of the random disturbance variables to the characteristic frequency during the perturbation process, and outputs the characteristic frequency jump variable, which is the mutation inflection point of the characteristic frequency at a specific inductance and the fluctuation amplitude of the mutation inflection point. Thus, the sensitivity coefficient of the characteristic frequency jump variable to the random disturbance variable can be further calculated. The sensitivity coefficient reflects the local instantaneous sensitivity and global contribution evaluation of the compensation capacitor variable to produce a unique characteristic frequency, making the influence of different compensation variables comparable, providing a highly reliable analysis basis for compensation capacitor frequency adjustment, and the adjusted characteristic frequency calculation formula is:

[0146] ,

[0147] wherein, is the distributed capacitance, is the compensation capacitor.

[0148] It should be noted that the present method can avoid the error frequency adjustment of traditional capacitor compensation adjustment based on intuition, greatly improve the compensation capacitor frequency adjustment accuracy of soil temperature measurement, and realize the frequency division multiplexing effect of high-precision soil temperature block measurement.

[0149] In addition, when using the capacitor compensation frequency adjustment scheme, considering the power frequency crosstalk and frequency band separation, the magnetic ring frequency division band should meet the following requirements: the number of turns of the primary coil and the number of turns of the secondary coil of the fixed second type of frequency division multiplexing magnetic ring are calculated according to the standard inductance frequency adjustment scheme ; then, the compensation capacitor with different capacitance values in parallel with the secondary coil of the second type of frequency division multiplexing magnetic ring is calculated to obtain the theoretical resonance frequency, and the specific theoretical resonance frequency calculation formula is:

[0150] ,

[0151] wherein, is the size of the compensation capacitor in parallel.

[0152] Finally, the frequency band isolation constraint and the magnetic ring of the channel power frequency harmonic avoidance constitute two types of frequency division multiplexing magnetic ring product series. Among them, the power frequency wave avoidance constraint is: .

[0153] In summary, by using the magnetic ring frequency band allocation rule algorithm, the standard inductance frequency modulation scheme, the magnetic ring design and the capacitor design in the capacitor compensation frequency modulation can ensure the frequency band isolation degree under extreme temperature and effectively avoid the overlap with the power frequency harmonic to generate inter-channel crosstalk.

[0154] Preferably, the introduced fast Fourier transform algorithm identifies the temperature measurement signal waveform, automatically establishes a resonance frequency-signal amplitude mapping table, extracts the signal amplitude of each frequency peak point through the mapping table, inversely analyzes the signal amplitude according to the theoretical proportional characteristic of signal amplitude-thermistor-temperature, and obtains the dynamic temperature value of the target temperature measurement channel, specifically including the following steps:

[0155] The introduced fast Fourier transform algorithm analyzes the temperature measurement signal waveform, obtains the magnetic ring resonance peak of the target temperature measurement channel, and converts the magnetic ring resonance peak into a sparse vector;

[0156] The sparse vector of the magnetic ring resonance peak is sampled by constructing a Gaussian random matrix, and the sparse coefficients of the sparse vector are solved and reconstructed by introducing an orthogonal matching pursuit algorithm in the sampling process to generate a reconstructed frequency spectrum;

[0157] According to the reconstructed frequency spectrum, the signal trend of the magnetic ring resonance peak is automatically identified, a resonance frequency-signal amplitude mapping table is established, and the actual signal amplitude corresponding to different frequency peak points on the magnetic ring resonance peak is extracted through the resonance frequency-signal amplitude mapping table;

[0158] The theoretical proportional characteristic of signal amplitude-thermistor-temperature is obtained, the actual signal amplitude is inversely calculated according to the theoretical proportional characteristic, a residual vector of the temperature generated by the actual signal amplitude driving the thermistor and a Jacobian matrix of temperature fluctuation are generated, and the theoretical proportional damping factor is adjusted combined with the residual vector and the Jacobian matrix, so as to update and iterate the temperature trend of the thermistor, and derive the current residual sum of squares;

[0159] If the current residual sum of squares compared with the preset residual sum of squares presents gradient growth, the temperature index corresponding to the current residual sum of squares is replaced by the proportional temperature corresponding to the actual signal amplitude;

[0160] If the current residual sum of squares is compared with the preset residual sum of squares and is a gradient descent, the update process is ignored, and the final output target temperature channel reaches the dynamic temperature value of each frequency peak point.

[0161] It should be noted that the magnetic ring resonance peak in the temperature measurement signal waveform is identified by fast Fourier transform, and the sparse vector of the magnetic ring resonance peak is sampled by Gaussian random matrix, so as to convert the physical characteristic that a small number of resonance peaks express non-zero coefficients into mathematical sparsity, thereby maximizing the key characteristic components of the magnetic ring resonance peak. Then solve the reconstructed sparse vector to recover the complete frequency domain signal characteristics and characteristic trend from the known resonance peak, preserve the resonance peak information while realizing signal trend recovery, and improve the mapping fidelity of the frequency peak point and the signal amplitude. The theoretical proportional characteristic of signal amplitude-thermistor-temperature is specifically:

[0162] ,

[0163] Among them, is the signal amplitude, is the thermistor, is the temperature.

[0164] The residual vector measures the sensitive error size and direction of the thermistor change with the actual signal amplitude at the current time sequence compared with the last time sequence, that is, the time sequence error size. The Jacobian matrix describes the sensitivity of the residual vector to the actual signal amplitude change, that is, the time sequence error change trend. The theoretical proportional damping factor is used to adjust the convergence rate of the unknown time sequence alternation, so that the inversion of the current soil temperature can better fit the theoretical proportional characteristic to calculate the accurate fluctuation trend, thereby outputting accurate temperature measurement value. Compared with the traditional "multiple passband filters + 1 spectrum analyzer" method, the temperature inversion demodulation by this method greatly reduces the hardware cost and can realize lightweight arrangement on site.

[0165] In addition, at very high temperatures, the values of the distributed capacitance, the compensation capacitance and the inductance value of the magnetic ring will drift. For this drift, the method uses the following compensation algorithm for correction. The correction calculation formula is:

[0166] ,

[0167] ,

[0168] ,

[0169] Among them, is the compensation capacitance drift rate, is the distributed capacitance drift rate, is the magnetic ring inductance coefficient drift rate. To calibrate temperature (usually 25℃).

[0170] In summary, the method effectively solves the problem that the temperature measurement signal data cannot be normally captured due to the frequency drift caused by the high temperature environment by applying a specific compensation algorithm at the output signal end, significantly reduces the signal demodulation error rate, and significantly improves the accuracy and reliability of the soil temperature measurement results.

[0171] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A modular magnetic isolation frequency division multiplexing soil temperature measurement system, characterized in that, The standard modular unit comprises a temperature measurement building block unit and a relay unit: The temperature measurement building block unit is provided with a first core temperature measurement element and a second core temperature measurement element, the first core temperature measurement element is composed of a magnetic ring primary coil with a fixed number of turns, and the first core temperature measurement element is connected to an excitation bus; The second core temperature measurement element is divided into a standard capacitor version and a capacitor compensation version according to different design requirements of different use methods, the second core temperature measurement element of the standard capacitor version is connected in series with a thermal sensing resistor through a magnetic ring secondary coil, and the second core temperature measurement element of the capacitor compensation version is connected in parallel with a compensation capacitor and then connected in series with the thermal sensing resistor independently, wherein the thermal sensing resistor is of PT100 type, and the second core temperature measurement element is connected to a signal bus; The temperature measurement building block unit comprises a tail component and a non-tail component, wherein the temperature measurement building block unit of the tail component is usually used as the bottommost temperature measurement module of the deep well, for temperature measurement at the deepest or farthest position of the deep well, and the bottom is designed as a plugging head; The relay unit is a pure cable transmission module, and the relay unit and the temperature measurement building block unit are used in combination when measuring soil temperature.

2. The modular magnetic isolation frequency division multiplexing soil temperature sensing system of claim 1, wherein, The temperature measurement building block unit of the non-tail component is mainly used as an assembly module capable of filtering different modulation signals, and the non-tail component and the tail component are provided with obvious color distinction marks outside, which are used for modular assembly distinction of different temperature measurement building block units.

3. The modular magnetic isolation frequency division multiplexing soil temperature sensing system of claim 1, wherein, The excitation bus and the signal bus of the temperature measurement building block unit of the tail component are connected to only one aircraft carrier joint at the top end, while the excitation bus and the signal bus of the temperature measurement building block unit of the non-tail component are connected to an aircraft public joint between temperature measurement units at the top end and connected to an aircraft carrier joint at the end, and the aircraft public joint and the aircraft carrier joint are both of IP68 protection grade, so that the aircraft joint can transmit an alternating constant current source to the excitation bus and carry mixed modulation signals on the signal bus, and the excitation bus and the signal bus are integrated into two groups of twisted wires.

4. The modular magnetic isolation frequency division multiplexing soil temperature sensing system of claim 1, wherein, The standard modular unit is matched with an external protective sleeve, and the length of the external protective sleeve is the same as that of the standard modular unit, the external protective sleeve is made of 304 stainless steel, and both ends are provided with threaded structures for screwing additional external protective sleeves and conical plugs.

5. An intelligent demodulation method of a building block type magnetic isolation frequency division multiplexing soil temperature measurement system, applied to the building block type magnetic isolation frequency division multiplexing soil temperature measurement system of any one of claims 1-4, characterized in that, Specifically comprising the following steps: At the excitation signal input end, time allocation is performed on the monitoring response time slots of the target temperature measurement channel to generate different sending time nodes, and the cloud and the edge MCU unit write corresponding excitation digital signals to the target temperature measurement channel of the DAC low-frequency function generator at different sending time nodes; Each target temperature measurement channel is matched with a power amplifier, the DAC low-frequency function generator outputs corresponding analog voltage to the power amplifier according to the excitation digital signal, and the power amplifier performs frequency remodeling calculation on the analog voltage to generate time sequence different frequency bands of each target temperature measurement channel at different sending time nodes; The wide frequency current of the excitation bus input time sequence heterodyne band excites the magnetic ring chain, at this time the real-time excitation frequency of the time sequence heterodyne band for the temperature measurement building block unit is obtained, if the real-time excitation frequency is greater than the tolerance excitation frequency threshold of the temperature measurement building block unit, the magnetic ring inside the temperature measurement building block unit is calibrated as a first type of frequency division multiplexing magnetic ring; otherwise, it is calibrated as a second type of frequency division multiplexing magnetic ring; If the magnetic ring is a first type of frequency division multiplexing magnetic ring, then the impedance condition presented at the only characteristic frequency of the magnetic ring output specific inductance is analyzed, and the standard inductance frequency modulation scheme is obtained according to the analysis result; If the magnetic ring is a second type of frequency division multiplexing magnetic ring, then the sensitivity of the characteristic frequency jump variable output by the random compensation variable calculation of the power simulation model disturbance compensation capacitor to the random compensation variable is calculated, and the sensitivity coefficient is analyzed to adjust the parameters of the compensation capacitor, and the capacitor compensation frequency modulation scheme is obtained; At the signal output end, the temperature measurement signal waveform is acquired after frequency modulation based on the standard inductance frequency modulation scheme and the capacitor compensation frequency modulation scheme, and is directly transmitted to the cloud end or the gateway end with an edge computing module through a 4G module; The fast Fourier transform algorithm is introduced to identify the temperature measurement signal waveform, and a resonance frequency-signal amplitude mapping table is automatically established. The signal amplitude of each frequency peak point is extracted through the mapping table, and the dynamic temperature value of the target temperature measurement channel is obtained by inversely analyzing the signal amplitude according to the theoretical proportional characteristic of signal amplitude-thermistor-temperature.

6. The intelligent demodulation method of the building block type magnetic isolation frequency division multiplexing soil temperature measurement system according to claim 5, characterized in that, The monitoring response time slot of the target temperature measurement channel is time-allocated at the excitation signal input end, different sending time nodes are generated, and corresponding excitation digital signals are written to the target temperature measurement channel of the DAC low-frequency function generator at different sending time nodes through the cloud and the edge MCU unit, which specifically includes the following steps: The target temperature measurement channel and the corresponding layout diagram are obtained, the arrival priority of the time sequence topology temperature measurement building block unit on different target temperature measurement channels is constructed according to the layout diagram, and a temperature measurement cut-off topology structure is constructed; The time sequence asynchronous characteristics of each target temperature measurement channel are obtained through the temperature measurement cut-off topology structure, and the least common multiple of the execution cycle of all target temperature measurement channels is calculated according to the time sequence asynchronous characteristics, and the super-asynchronous cycle of the temperature measurement building block unit is obtained; In the super-asynchronous cycle, the time is divided into time step slots with fixed time span, and the bus sending time slot window of the preset time step slot is embedded. If the conflict rate of the given monitoring response time slot of the target temperature measurement channel embedded in the bus sending time slot window is lower than the preset conflict rate, the target temperature measurement channel is allocated to the time step slot; Repeat the embedding step and the conflict analysis step until all target temperature measurement channels are fixedly allocated to design excitation time sequence scheduling, and generate sending time nodes for exciting different target temperature measurement channels; The magnetic ring mutual inductance design drawing of the temperature measurement building block unit is obtained, and the magnetic ring characteristic frequency of the temperature measurement building block unit deployed on multiple different target temperature measurement channels is extracted through the magnetic ring mutual inductance design drawing; Through the cloud and the edge MCU unit, corresponding excitation digital signals are written to the target temperature measurement channel of the DAC low-frequency function generator at different sending time nodes according to the frequency paradigm that maintains the maximum approximate matching degree with the magnetic ring characteristic frequency.

7. The intelligent demodulation method of the building block type magnetic isolation frequency division multiplexing soil temperature measuring system according to claim 5, characterized in that, The power amplifier carries out frequency reshaping calculation of power gain of analog voltage, generates time sequence different frequency bands of each target temperature measurement channel at different sending time nodes, and specifically includes the following steps: Obtain the model specification, bandwidth range and distortion decision of the power amplifier, retrieve the power gain-frequency reshaping projection system suitable for different channel corresponding power amplifiers in the big data network based on the model specification, bandwidth range and distortion decision; Based on the power gain-frequency reshaping projection system, the power convolution interleaving rule and the frequency shift register of different sending time nodes are constructed, and the excitation digital signal data stream is divided into equal length signal data blocks; According to the convolution interleaving rule, the signal data blocks of different channels are inserted into the power gain output along the shift registers, at this time the interleaved digital signal data is merged into the communication link of the same DAC low frequency function generator according to the excitation time sequence of the sending time node, forming a series of continuous multiplexed frequency signal streams; According to a series of the multiplexed frequency signal streams, the corresponding analog voltage is converted and output by the DAC low frequency function generator and transmitted to the power amplifier, and the interleaving of the continuous multiplexed frequency signal streams is calculated according to the convolution interleaving rule to shape the frequency sequence of the recovered original signal data, and finally generate the time sequence different frequency bands of each target temperature measurement channel at different sending time nodes.

8. The intelligent demodulation method of the building block type magnetic isolation frequency division multiplexing soil temperature measuring system according to claim 5, characterized in that, If the magnetic ring is a type of frequency division multiplexing magnetic ring, the impedance condition presented at the unique characteristic frequency when the magnetic ring outputs a specific inductance is analyzed, and the standard inductance frequency modulation scheme is obtained by performing orthogonal frequency modulation and reference frequency modulation according to the analysis result, specifically including the following steps: If the magnetic ring is a type of frequency division multiplexing magnetic ring, then one or more real-time specific inductance of the type of frequency division multiplexing magnetic ring at the excitation time sequence in the wide frequency current excitation process is obtained, and the electrodynamics knowledge graph is obtained based on the big data network; Through the electrodynamics knowledge graph, each of the real-time specific inductance is identified, and a complex carrier coding worldview for specific inductance impedance imaging is output, and the unique characteristic frequency of the type of frequency division multiplexing magnetic ring is obtained; A standard carrier spectrum model of the unique characteristic frequency is constructed, the real-time specific inductance is mapped by carrier impedance using the complex carrier coding worldview, the impedance complex modulation symbol of each real-time specific inductance is obtained, each of the impedance complex modulation symbol is allocated to the subcarrier sequence segment recorded in the standard carrier spectrum model according to the excitation time sequence frequency domain, and the excitation impedance value of the type of frequency division multiplexing magnetic ring at different subcarriers is obtained; A minimum impedance threshold at the unique characteristic frequency is preset, if the excitation impedance value is less than the minimum impedance threshold, the reference segment of 0 at the subcarrier position corresponding to the excitation impedance value is marked, if the excitation impedance value is greater than the minimum impedance threshold, the orthogonal segment of 1 at the subcarrier position is marked, and the frequency modulation analysis result is obtained; The actual carrier spectrum model of the type of frequency division multiplexing magnetic ring is obtained, the dislocation degree between the actual carrier spectrum model and the standard carrier spectrum model is calculated, only the model region corresponding to the dislocation degree greater than the preset dislocation degree is extracted, and the main frequency modulation region is marked, If the main frequency modulation region is a quadrature segment displayed as 1, a quadrature modulation frequency segment based on the degree of misplacement is filled for the main frequency modulation region; if the main frequency modulation region is a reference segment displayed as 0, a fixed reference modulation frequency segment is supplemented for the main frequency modulation region; The standard inductance frequency modulation scheme is obtained according to the quadrature modulation frequency segment and the reference modulation frequency segment.

9. The intelligent demodulation method of the building block type magnetic isolation frequency division multiplexing soil temperature measuring system according to claim 5, characterized in that, If the magnetic ring is a two-type frequency division multiplexing magnetic ring, then the impedance condition of the magnetic ring at the unique characteristic frequency when a specific inductance is output is analyzed, and the quadrature frequency modulation and the reference frequency modulation are performed according to the analysis result to obtain the standard inductance frequency modulation scheme, which specifically includes the following steps: If the magnetic ring is a two-type frequency division multiplexing magnetic ring, then the fixed number of turns of the secondary coil of the magnetic ring is obtained according to the unique characteristic frequency of the two-type frequency division multiplexing magnetic ring, and an electrical simulation model of the two-type frequency division multiplexing magnetic ring is constructed through an electrical simulation software; The prior distribution of disturbance transfer about the two-type frequency division multiplexing magnetic ring is obtained through the parallel structure of the compensation capacitor, the inductance characteristics under the low-frequency condition, and the compensable elements for the fixed number of turns in the big data network search, and the normal compensation disturbance criterion is constructed based on the prior node pattern and the parameters of the prior distribution of disturbance transfer; The Latin hypercube sampling algorithm is introduced, and the disturbance variables of the compensation capacitor in the two-type frequency division multiplexing magnetic ring are sampled based on the normal compensation disturbance criterion in the Latin hypercube sampling algorithm to obtain a random compensation variable matrix of the compensation capacitor; The partial derivative type disturbance is applied by substituting the random compensation variable matrix into the local reference point of the electrical simulation software, and the Sobol contribution index of the random disturbance variable to the characteristic frequency is analyzed in the overall range of the input space of the model to record and obtain the characteristic frequency jump variable of the two-type frequency division multiplexing magnetic ring; The sensitivity coefficient threshold is preset based on the unique characteristic frequency, and the sensitivity coefficient of the characteristic frequency jump variable to the Sobol contribution index of the random disturbance variable is calculated based on the partial derivative; If the sensitivity coefficient is greater than the sensitivity coefficient threshold, it indicates that the random compensation variable makes the compensation parameter of the specific inductance of the two-type frequency division multiplexing magnetic ring at the characteristic frequency reach a large compensation parameter for the minimum impedance, and the compensation capacitor needs to be adjusted in a decreasing manner; If the sensitivity coefficient is less than the sensitivity coefficient threshold, it indicates that the random compensation variable makes the compensation parameter of the specific inductance of the two-type frequency division multiplexing magnetic ring at the characteristic frequency reach a small compensation parameter for the minimum impedance, and the compensation capacitor needs to be adjusted in an increasing manner to generate a capacitor compensation frequency modulation scheme.

10. The intelligent demodulation method of the building block type magnetic isolation frequency division multiplexing soil temperature measuring system according to claim 5, characterized in that, The fast Fourier transform algorithm is introduced to identify the temperature measurement signal waveform, automatically establish a resonance frequency-signal amplitude mapping table, extract the signal amplitude of each frequency peak point through the mapping table, and inversely analyze the signal amplitude according to the theoretical proportional characteristic of the signal amplitude-thermistor-temperature to obtain the dynamic temperature value of the target temperature measurement channel, which specifically includes the following steps: The fast Fourier transform algorithm is introduced to analyze the temperature measurement signal waveform, obtain the magnetic ring resonance peak of the target temperature measurement channel, and convert the magnetic ring resonance peak into a sparse vector; A Gaussian random matrix is constructed to sample the sparse vector of the magnetic ring resonance peak, and the orthogonal matching pursuit algorithm is introduced to solve and reconstruct the sparse coefficients of the sparse vector during the sampling process to generate a reconstructed frequency spectrum; According to the signal trend of automatically identifying the magnetic loop resonance peak from the reconstructed spectrum, a mapping table of resonance frequency-signal amplitude is established, and the actual signal amplitude corresponding to the different frequency peak points on the magnetic loop resonance peak is extracted through the mapping table of resonance frequency-signal amplitude; A theoretical proportional characteristic of signal amplitude-thermistor-temperature is obtained, the actual signal amplitude is inversely calculated according to the theoretical proportional characteristic, a residual vector of the temperature generated by the actual signal amplitude driving the thermistor and a Jacobian matrix of the temperature fluctuation are generated, the theoretical proportional damping factor is adjusted combined with the residual vector and the Jacobian matrix, and the temperature trend of the iterative thermistor is updated, and the current residual sum of squares is derived; If the current residual sum of squares compared with the preset residual sum of squares presents gradient growth, the temperature index corresponding to the current residual sum of squares is replaced by the proportional temperature corresponding to the actual signal amplitude; If the current residual sum of squares compared with the preset residual sum of squares presents gradient decline, the update process is ignored, and finally the dynamic temperature value of the target temperature measurement channel when reaching each frequency peak point is output.

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