Ultra-sensitive temperature sensing system and use method thereof

Abstract

The ultra-sensitive temperature sensing system comprises a receiver circuit and a detector circuit, the receiver circuit comprises a first inductance coil, a first resistor and a first resonant capacitor which are connected in parallel, and the detector circuit comprises a second inductance coil, a second resistor and a second resonant capacitor which are connected in parallel. Wherein the second resistor comprises a thermistor and an adjustable resistor which are connected in parallel, and the ultra-sensitive temperature sensing system meets the following relation so that the ultra-sensitive temperature sensing system can be located at a singular point: beta2 = + / -2eta + beta1; aiming at the problems of insufficient sensitivity and weak anti-interference capability of a traditional temperature detector, the nonlinear response characteristic near a singular point is utilized, and the sensitivity is greatly improved compared with that of traditional thermoelectric detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sensing technology, in particular to a super-sensitive temperature sensing system and a method of using the same. BACKGROUND

[0002] Sensors play a key role in modern society and are widely used in industrial automation, environmental monitoring, biomedical detection, wireless communication and other fields. With the rapid development of intelligent and automated systems, the demand for non-contact, high-precision, fast-response sensing technology is increasing. In the field of medical health, high-precision monitoring of local tissue temperature can be applied to the diagnosis and intervention of early pathological changes; in the field of bionic robots, super-sensitive temperature sensors can endow mechanical hands with the ability to identify the thermal physical parameters (such as thermal conductivity) of objects; in the industrial field, high-precision temperature monitoring is involved in many key links, and accurate temperature control is an important guarantee for process optimization and safety warning. Therefore, realizing real-time detection of high-precision and high-robustness temperature changes has become one of the core directions of current temperature sensing technology development.

[0003] With the development of topological physics, especially the research progress of Exceptional Point (EP) in non-Hermitian systems, a new way is provided for the improvement of detector performance. Exceptional Point is a kind of non-Hermitian singular point with simultaneous degeneracy of complex eigenvalues and their corresponding eigenvectors. The system has extremely high sensitivity to small perturbations near the EP, which makes the detector based on EP show great advantages in detecting weak signals.

[0004] Traditional temperature detectors (such as thermistors and thermocouples) achieve temperature sensing by directly measuring resistance or voltage changes. Their resolution is limited by environmental temperature fluctuations, thermal noise and device drift. Under conditions of small temperature difference or low thermal conductivity, the temperature resolution is significantly reduced, and the dynamic range is limited, making it difficult to meet the demand for high-precision micro-temperature difference detection. By utilizing the nonlinear response of the system near the EP to perturbations, the resolution of the detector can be improved by orders of magnitude compared to traditional temperature detection methods, providing a new way for weak temperature difference or high-precision temperature sensing. The integration of thermistors and LC circuits is low in cost and suitable for scenarios such as pathophysiological heat change monitoring and industrial automation temperature monitoring.

[0005] The disclosure of the above background art content is only used to assist in understanding the inventive concept and technical solutions of the present application, and it does not necessarily belong to the prior art of the present application, nor does it necessarily provide technical teaching. In the absence of explicit evidence that the above content was disclosed before the filing date of the present application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0006] The purpose of the present application is to provide a super-sensitive temperature sensing system and a method of using the same.

[0007] To achieve the above object, the technical scheme adopted by the first aspect of the present application is as follows:

[0008] An ultra-sensitive temperature sensing system, comprising a receiver circuit and a detector circuit, wherein the receiver circuit comprises a first inductor coil, a first resistor and a first resonant capacitor in parallel, the detector circuit comprises a second inductor coil, a second resistor and a second resonant capacitor in parallel, wherein the second resistor is composed of a thermistor and an adjustable resistor in parallel, the ultra-sensitive temperature sensing system satisfies the following relationship to make the ultra-sensitive temperature sensing system at a singular point:

[0009] β2=±2η+β1;

[0010] wherein, A2 is the total resistance value of the thermistor and the adjustable resistor in parallel, A1 is the resistance value of the first resistor, B is the inductance value of the first inductor coil and the second inductor coil, D is the capacitance value of the first resonant capacitor and the second resonant capacitor, and K is the mutual inductance coupling coefficient between the receiver circuit and the detector circuit.

[0011] In some embodiments, the inductance values of the first inductor coil and the second inductor coil are equal, and / or the capacitance values of the first resonant capacitor and the second resonant capacitor are equal.

[0012] In some embodiments, the receiver circuit further comprises an alternating current source in series with the first resistor.

[0013] In some embodiments, when the resistance value of the thermistor changes with temperature, the resistance value of the adjustable resistor is adjusted to make the ultra-sensitive temperature sensing system work near the singular point. This is mainly applied to the case where the ambient temperature changes greatly, which expands the temperature detection range of the ultra-sensitive temperature sensing system in the present application and enriches its application scenarios.

[0014] In some embodiments, the corresponding external temperature change value is obtained by detecting the frequency splitting of the ultra-sensitive temperature sensing system.

[0015] To achieve the above object, the technical scheme adopted by the second aspect of the present application is as follows:

[0016] A use method of an ultra-sensitive temperature sensing system, comprising the following steps:

[0017] Constructing a singular point: making the ultra-sensitive temperature sensing system satisfy:

[0018] β2=±2η+β1;

[0019] wherein, A2 is the total resistance value of the parallel-connected thermistor and adjustable resistor, A1 is the resistance value of the first resistor, B is the inductance value of the first inductor coil and the second inductor coil, D is the capacitance value of the first resonant capacitor and the second resonant capacitor, and K is the mutual inductive coupling coefficient between the receiver circuit and the detector circuit;

[0020] constructing the receiver circuit: connecting the first inductor coil, the first resistor and the first resonant capacitor in parallel to obtain the receiver circuit;

[0021] constructing the detector circuit: connecting the second inductor coil, the thermistor, the adjustable resistor and the second resonant capacitor in parallel to obtain the detector circuit;

[0022] calculating the temperature change value: detecting the frequency split of the ultra-sensitive temperature sensing system to obtain the corresponding external temperature change value.

[0023] In some embodiments, between the step of constructing the detector circuit and the step of calculating the temperature change value, there is further included adjusting the adjustable resistor: when the ambient temperature causes the resistance of the thermistor to change, and the system deviates from the singularity point, the resistance of the adjustable resistor needs to be adjusted again to satisfy:

[0024] β2=±2η+β1,

[0025] The ultra-sensitive temperature sensing system works near the singularity point. This mainly applies to the case where the ambient temperature changes greatly, which expands the temperature detection range of the ultra-sensitive temperature sensing system in the application and enriches the application scenarios.

[0026] In some embodiments, in the step of constructing the detector circuit, the inductance values of the first inductor coil and the second inductor coil are equal, and / or, in the step of constructing the detector circuit, the capacitance values of the first resonant capacitor and the second resonant capacitor are equal.

[0027] In some embodiments, in the step of constructing the receiver circuit, an alternating current source is further connected in series with the first resistor.

[0028] In some embodiments, in the step of calculating the temperature change value, based on the corresponding relationship between the resistance change of the thermistor and the temperature change, the corresponding external temperature change value is obtained

[0029] The technical scheme provided by the application has the following beneficial effects:

[0030] a. In view of the problems of insufficient sensitivity and weak anti-interference ability of the conventional temperature detector, the present application constructs a super-sensitive temperature sensing system of singular point composed of a receiver circuit and a detector circuit, energy transmission from the detector to the receiver is realized through mutual inductive coupling, the detector circuit uses a thermistor as a cavity resistance, the environmental temperature change drives the system to work near the singular point, and temperature-electric signal conversion is realized by monitoring frequency splitting. The sensitivity is greatly improved compared with the conventional thermoelectric detection by using the nonlinear response characteristics near the singular point.

[0031] b. The system circuit disclosed by the present application has simple structure and wide application scenarios, and is suitable for pathological physiological heat change monitoring, industrial automation temperature monitoring and the like. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0033] Figure 1 The schematic diagram of the super-sensitive temperature sensing system provided for an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to enable the persons skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort should belong to the scope of protection of the present application.

[0035] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, device, product or equipment including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or equipment.

[0036] AsFigure 1 As shown, in some embodiments of the present application, a super-sensitive temperature sensing system is provided, by which temperature can be sensitively detected.

[0037] In some embodiments, the super-sensitive temperature sensing system of the present application specifically comprises a receiver circuit and a detector circuit.

[0038] The receiver circuit comprises a first inductor coil (B1) in parallel, a first resistor (A1) and a first resonant capacitor (D1), wherein the receiver circuit further comprises an AC source (V0) in series with the first resistor in some embodiments. Figure 1 Figure 1 Figure 1 Figure 1 The detector circuit comprises a second inductor coil (B2) in parallel, a second resistor (A2) and a second resonant capacitor (D2), wherein the second resistor is composed of a thermistor (A

[0039] The detector circuit comprises a second inductor coil (B2) in parallel, a second resistor (A2) and a second resonant capacitor (D2), wherein the second resistor is composed of a thermistor (A Figure 1 Figure 1 Figure 1 Figure 1 t The inductance values of the first inductor coil and the second inductor coil are equal, and the capacitance values of the first resonant capacitor and the second resonant capacitor are equal. Figure 1

[0040] The super-sensitive temperature sensing system satisfies the following relationship to make the super-sensitive temperature sensing system at a singular point:

[0041] β2=±2η+β1;

[0042] Wherein, A2 is the total resistance value of the thermistor and the adjustable resistor in parallel, and the initial resistance value of the thermistor and the resistance value of the adjustable resistor are not equal, A1 is the resistance value of the first resistor, B is the inductance value of the first inductor coil and the second inductor coil, D is the capacitance value of the first resonant capacitor and the second resonant capacitor, and K is the mutual inductive coupling coefficient between the receiver circuit and the detector circuit.

[0043] For β2=±2η+β1, the calculation process is as follows:

[0044] For the coupled inductor, the relationship between voltage and current is:

[0045] V1=jωB1I1+jωKI2, (1)

[0046] V2=jωB2I2+jωKI1, (2)

[0047] ​​​​​​​​Wherein, V1 is the voltage across the first inductor in the receiver circuit, V2 is the voltage across the second inductor in the detector circuit, I1 is the current flowing through the first inductor, I2 is the current flowing through the second inductor, B1 is the inductance of the first inductor, B2 is the inductance of the second inductor, B1=B2=B, K is the mutual inductance coupling coefficient between the receiver circuit and the detector circuit, j is the imaginary unit, and ω is the frequency of the AC source.

[0048] For the receiver circuit and the detector circuit, the voltage-current relationship satisfies the following Kirchhoff equations, respectively:

[0049]

[0050] Wherein, A1 is the resistance of the first resistor in the receiver circuit, A2 is the total resistance of the parallel-connected thermistor and adjustable resistor on the detector side, D1 is the capacitance of the first resonant capacitor, D2 is the capacitance of the second resonant capacitor, and D1=D2=D.

[0051] Substituting formulas (1) and (2) into formulas (3) and (4) and eliminating V1 and V2, the equation containing only I1 and I2 and the circuit element parameters is obtained as follows:

[0052]

[0053] Wherein, is the resonant frequency of the resonant cavity of the receiver circuit and the detector circuit when the coupling is zero.

[0054] The equation is written in the form of a matrix, and there is

[0055]

[0056] Assume ω=ω0-Δ ω and Δω<<1, there is and ω≈ω0,

[0057] The equation set is simplified as follows:

[0058]

[0059] Further assume and Multiply ω0 / 2 on both sides of the equation, and obtain

[0060]

[0061] Substitute into the left matrix of the equation, and obtain

[0062]

[0063] Define the characteristic quantity The circuit equivalent Hamiltonian is obtained as:

[0064]

[0065] The eigen equation of the system det(H-Iω)=0 is solved, i.e.

[0066] [ω0(1-jβ1)-ω][ω0(1-jβ2)-ω]-(ηω0) 2 =0,

[0067] The eigen frequency of the system is obtained as:

[0068]

[0069] where ω1and ω2are both the resonance frequencies of the coupled system.

[0070] When the system is at the singular point, the eigen frequency of the system is degenerate, and ω1=ω2. From the expression of ω1and ω2, it can be seen that when 4η 2 -(β1-β2) 2 =0, ω1=ω2, which indicates that when the system is at the singular point, the parameters satisfy the condition β2=±2η+β1.

[0071] Therefore, the super-sensitive temperature sensing system in the present application can be set at the singular point by β2=±2η+β1.

[0072] In an example, the condition β2=2η+β1is taken, and the calculation can obtain the working frequency of the sensing system at the singular point as ω 1，2 =ω0(1-j(η+β1)).

[0073] Considering that a small perturbation is given to the thermistor by the temperature near the singular point, the resistance change of the thermistor is denoted as δ, then where β'2represents the parameter value of β2after the temperature change, is the partial derivative symbol, representing the partial derivative of the dependent variable β2with respect to its independent variable A2, and substituting the above expression of the eigen frequency of the system into the expression, the frequency splitting of the receiver circuit side is obtained as:

[0074]

[0075] When the system is at the singular point, 4η 2 -(β1-β2) 2 =0 is satisfied, and combined with the above expression of the frequency splitting of the receiver circuit side is obtained as:

[0076]

[0077] When the change amount δ is very small, δ 2 The final frequency splitting expression is obtained:

[0078]

[0079] According to the final frequency splitting expression, the value of the frequency splitting is proportional to the 1 / 2 power of the change of the resistance of the thermistor, which indicates that the sensing system of the present application has extremely sensitive response to the slight change of the temperature near the singular point.

[0080] The final frequency splitting expression of the super-sensitive temperature sensing system in the present application is verified by using the simulation software Multisim, with B=0.2mH, D=2nF, K=0.02mH, A1=50000Ω, A2=A0+A t The initial value of A0 is 7110Ω, wherein A t The initial resistance and A0 are not equal. The thermistor is selected from the TFPT0805 series, and the thermistor is 4kΩ near the normal temperature of 25℃. When the temperature changes by 0.061℃, the resistance of the thermistor changes by 1Ω, and the resonant frequency of the sensing system is split by 2000Hz. When the above values are directly substituted into the final frequency splitting expression, the following is obtained:

[0081]

[0082] That is, the resonant frequency of the sensing system obtained by the simulation software Multisim and the resonant frequency splitting of the sensing system obtained by direct calculation are both in the order of thousands of hertz.

[0083] As a comparison, the simulation software Multisim is further used to verify that A2=5000Ω, at this time the system works at a non-singular point, and the resonant frequency splitting of the system is about 10Hz when the temperature changes by 0.061℃. Therefore, the sensitivity is significantly improved at the singular point.

[0084] It can be seen that whether the final frequency splitting expression obtained by theoretical analysis or simulation simulation, the super-sensitive temperature sensing system of the present application has extremely sensitive response to the slight change of the temperature.

[0085] The present application also provides a use method of the super-sensitive temperature sensing system, comprising the following steps:

[0086] Constructing a singular point: making the super-sensitive temperature sensing system satisfy:

[0087] β2=±2η+β1;

[0088] wherein, A2 is the total resistance value of the parallel thermistor and adjustable resistor, and the initial resistance value of the thermistor and the resistance value of the adjustable resistor are not equal, A1 is the resistance value of the first resistor, B is the inductance value of the first inductor and the second inductor, D is the capacitance value of the first resonance capacitor and the second resonance capacitor, and K is the mutual inductive coupling coefficient between the receiver circuit and the detector circuit.

[0089] Constructing the receiver circuit: connecting the first inductor, the first resistor and the first resonance capacitor in parallel to obtain the receiver circuit; in some embodiments, when constructing the receiver circuit, the alternating current source V0 is also connected in series with the first resistor.

[0090] Constructing the detector circuit: connecting the second inductor, the thermistor, the adjustable resistor and the second resonance capacitor in parallel to obtain the detector circuit, wherein the inductance value of the first inductor and the second inductor is equal, and the capacitance value of the first resonance capacitor and the second resonance capacitor is equal.

[0091] Calculating the temperature change value: detecting the frequency split of the ultra-sensitive temperature sensing system to obtain the corresponding external temperature change value. Specifically, the change of the environment temperature causes the change of the thermistor, which leads to the deviation of the sensing system from the original singular point, changes the resonance frequency of the receiver circuit, and calculates the quantitative detection temperature through the resonance frequency split Δω. The detection of the resonance frequency split Δω can be obtained by monitoring the change of the output voltage amplitude with the frequency in the receiver circuit. In the simulation software Multisim, the resistance value of the thermistor is adjusted. When the resonance frequency split given by the simulation software Multisim is the same as the actually measured resonance frequency split, the resistance value of the thermistor in the simulation software at this time is the resistance value of the actual thermistor. Based on the corresponding relationship between the resistance value change of the thermistor and the temperature change, the corresponding temperature change value is obtained.

[0092] In some embodiments, between the step of constructing the detector circuit and the step of calculating the temperature change value, there is also a step of adjusting the adjustable resistor: when the resistance value of the thermistor changes due to the change of the environment temperature, the resistance value of the adjustable resistor is adjusted to satisfy:

[0093] β2=±2η+β1,

[0094] Making the ultra-sensitive temperature sensing system work near the singular point. This step is mainly applied to the case where the environment temperature changes greatly. When the environment temperature changes little, such as in the range of 0-1℃, this step can be omitted.

[0095] In summary, the present application is analyzed and simulated by the ultra-sensitive temperature sensing system, the results show that even without using negative resistance, the sensing system can still appear singular point under certain parameter conditions, and the singular point of the system under the condition of mutual coupling has high sensitivity resonance frequency characteristics related to circuit parameters. At the singular point, the sensitivity is the highest, when the change of environmental temperature causes the change of the resistance value of the detection end, the resonance frequency of the receiver circuit will be obviously split when the system deviates from the original singular point. By monitoring the change of the output voltage of the receiver circuit with frequency, the ultra-high sensitivity conversion of temperature-electric signal is realized, so as to realize the high-precision detection of environmental change. Compared with using negative resistance to construct singular point, the present application enhances the universality of LC circuit, and simplifies the circuit structure, so it has more application scenarios.

[0096] The above description is merely a specific implementation of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should be considered as the protection scope of the present application.

Claims

1. An ultra-sensitive temperature sensing system, characterized in that, The super-sensitive temperature sensing system comprises a receiver circuit and a detector circuit, wherein the receiver circuit comprises a first inductor coil, a first resistor and a first resonant capacitor in parallel, the detector circuit comprises a second inductor coil, a second resistor and a second resonant capacitor in parallel, wherein the second resistor is composed of a thermistor and an adjustable resistor in parallel, the super-sensitive temperature sensing system satisfies the following relationship to make the super-sensitive temperature sensing system at a singular point: β2 = ±2η + β1; wherein, A2 is the total resistance value of the thermistor and the adjustable resistor in parallel, A1 is the resistance value of the first resistor, B is the inductance value of the first inductor coil and the second inductor coil, D is the capacitance value of the first resonance capacitor and the second resonance capacitor, and K is the mutual inductive coupling coefficient between the receiver circuit and the detector circuit.

2. The ultra-sensitive temperature sensing system of claim 1, wherein, The inductance of the first inductor coil and the second inductor coil is equal, and / or the capacitance of the first resonant capacitor and the second resonant capacitor is equal.

3. The ultra-sensitive temperature sensing system of claim 1, wherein, The receiver circuit further comprises an alternating current source in series with the first resistor.

4. The ultra-sensitive temperature sensing system of claim 1, wherein, When the resistance of the thermistor changes with temperature, the resistance of the adjustable resistor is adjusted to make the super-sensitive temperature sensing system work near the singular point.

5. The ultra-sensitive temperature sensing system of claim 1, wherein, The corresponding external temperature change value is obtained by detecting the frequency split of the super-sensitive temperature sensing system.

6. A method of using a super-sensitive temperature sensing system, characterized by, The method comprises the following steps: Constructing a singular point: making the super-sensitive temperature sensing system satisfy: β2＝±2n+β1； wherein, A2 is the total resistance value of the parallel-connected thermistor and adjustable resistor, A1 is the resistance value of the first resistor, B is the inductance value of the first inductor coil and the second inductor coil, D is the capacitance value of the first resonance capacitor and the second resonance capacitor, and K is the mutual inductive coupling coefficient between the receiver circuit and the detector circuit. Constructing a receiver circuit: connecting a first inductor coil, a first resistor and a first resonant capacitor in parallel to obtain the receiver circuit; Constructing a detector circuit: connecting a second inductor coil, a thermistor, an adjustable resistor and a second resonant capacitor in parallel to obtain the detector circuit; Calculating the temperature change value: detecting the frequency split of the super-sensitive temperature sensing system to obtain the corresponding external temperature change value.

7. The method of using a supersensitive temperature sensing system of claim 6, wherein: Between the steps of constructing the detector circuit and calculating the temperature change value, the method further comprises adjusting the adjustable resistor: when the resistance of the thermistor changes due to the change of the ambient temperature and the system deviates from the singular point significantly, the resistance of the adjustable resistor needs to be adjusted again to satisfy: β2 = ±2η + β1, So that the super-sensitive temperature sensing system works near the singular point.

8. The method of using a supersensitive temperature sensing system of claim 6, wherein: In the step of constructing the detector circuit, the inductance of the first inductor coil and the second inductor coil is equal, and / or in the step of constructing the detector circuit, the capacitance of the first resonant capacitor and the second resonant capacitor is equal.

9. The method of using a supersensitive temperature sensing system of claim 6, wherein: In the step of constructing the receiver circuit, an alternating current source is connected in series with the first resistor.

10. The method of using a supersensitive temperature sensing system of claim 6, wherein: In the step of calculating the temperature change value, the corresponding external temperature change value is obtained based on the corresponding relationship between the resistance change of the thermistor and the temperature change. In the step of calculating the temperature change value, the corresponding external temperature change value is obtained based on the corresponding relationship between the resistance change of the thermistor and the temperature change.

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