Temperature detection method of a composite temperature sensor

Abstract

The application provides a temperature detection method of a composite temperature sensor, which comprises the following steps: S10, electrically connecting a second end of a first temperature sensor and a first end of a second temperature sensor; S20, applying an initial excitation current to the composite temperature sensor, collecting the resistance of the composite temperature sensor at an initial moment, and obtaining the temperature at the initial moment based on the resistance of the composite temperature sensor at the initial moment; S30, obtaining the sensitivity at a current moment based on the resistance of the composite temperature sensor at the current moment and the temperature at the current moment; determining the excitation current at a next moment and the detection signal of the composite temperature sensor at the next moment according to the sensitivity at the current moment; S40, taking the result of dividing the detection signal of the composite temperature sensor at the next moment by the excitation current at the next moment as the resistance of the composite temperature sensor at the next moment; S50, obtaining the temperature at the next moment based on the resistance of the composite temperature sensor at the next moment; and S60, repeating S30-S50 to complete the temperature detection at subsequent moments.

Description

Technical Field

[0001] This invention relates to the field of temperature sensor technology, and in particular to a temperature detection method using a composite temperature sensor. Background Technology

[0002] Temperature measurement is crucial in scientific research, industrial process control, aerospace, and energy fields. In particular, in scenarios such as deep space exploration, superconducting research, and cold chain transportation, sensors are required to operate reliably in extremely low temperatures (such as -269°C to -196°C); while in applications such as engine monitoring, metallurgy, and chemical engineering, they must withstand high temperatures (such as exceeding 500°C).

[0003] Currently, mainstream temperature sensing technologies on the market all have significant limitations:

[0004] 1. Thermocouples have a wide high-temperature range, but their accuracy and sensitivity are insufficient in the low-temperature range;

[0005] 2. Although platinum resistance temperature sensors (RTDs) have high accuracy, their sensitivity drops sharply at extremely low temperatures, and they are also very expensive.

[0006] 3. Thermistors have a narrow temperature measurement range and cannot cover both extremely low and high temperatures;

[0007] 4. The temperature range of semiconductor integrated sensors is extremely limited.

[0008] The technical limitations of the aforementioned sensor performance mean that applications covering a wide temperature range must use multiple sensor systems, which not only increases system complexity and cost but also makes it difficult to guarantee measurement consistency and reliability. Summary of the Invention

[0009] This invention provides a temperature detection method for a composite temperature sensor, which can achieve good sensitivity in both extremely low and high temperature environments at a low cost, solving the problems of high cost and poor sensitivity in high temperature range of existing temperature sensors applied to extremely low temperature environments.

[0010] This invention provides a temperature detection method using a composite temperature sensor, the method comprising:

[0011] S10. Electrically connect the second end of the first temperature sensor and the first end of the second temperature sensor to realize the series connection of the two temperature sensors, thereby forming a composite temperature sensor; take the first end of the first temperature sensor as the first measurement point, the second end of the second temperature sensor as the second measurement point, and the connection point between the first temperature sensor and the second temperature sensor as the third measurement point; wherein, the temperature-resistance curve of the first temperature sensor is a direct proportional coefficient, and the temperature-resistance curve of the second temperature sensor is an inverse proportional coefficient.

[0012] S20. Apply an initial excitation current to the composite temperature sensor, collect the resistance of the composite temperature sensor at the initial moment, and obtain the temperature at the initial moment based on the resistance of the composite temperature sensor at the initial moment; wherein, the initial excitation current is set to an arbitrary value; the resistance of the composite temperature sensor at the initial moment is the sum of the resistance values ​​of the first temperature sensor and the second temperature sensor.

[0013] S30. Based on the current resistance and temperature of the composite temperature sensor, the sensitivity of the composite temperature sensor at the current moment is obtained. If the sensitivity at the current moment is less than -X, the excitation current at the next moment is adjusted to the 10uA level, and the voltage between the second and third measurement points is collected as the detection signal of the composite temperature sensor at the next moment. If the sensitivity at the current moment is greater than X, the excitation current at the next moment is adjusted to the 1mA level, and the voltage between the first and third measurement points is collected as the detection signal of the composite temperature sensor at the next moment. If the absolute value of the sensitivity at the current moment is less than or equal to X, the excitation current at the next moment is adjusted to the 100uA level, and the voltage between the first and second measurement points is collected as the detection signal of the composite temperature sensor at the next moment. Wherein, X is the preset sensitivity.

[0014] S40. Divide the detection signal of the composite temperature sensor at the next moment by the excitation current at the next moment and use the result as the resistance of the composite temperature sensor at the next moment.

[0015] S50. Obtain the temperature at the next moment based on the resistance of the composite temperature sensor at the next moment;

[0016] S60, repeat S30~S50 to complete the temperature detection at each subsequent time point.

[0017] Preferably, during the cooling process in the low-temperature range, the resistance of the first temperature sensor gradually decreases from less than 10Ω, and the resistance of the second temperature sensor gradually increases to the level of 1000Ω; during the heating process in the high-temperature range, the resistance of the second temperature sensor gradually decreases from less than 100Ω, and the resistance of the first temperature sensor gradually increases to the level of 100Ω.

[0018] Preferably, the temperature range of the low-temperature range is 4K~77K, and the temperature range of the high-temperature range is 77K~350K.

[0019] Preferably, the sensitivity of the composite temperature sensor at the current moment is obtained by the following formula:

[0020] D = d(R1 + R2) / dT

[0021] In the formula, D is the sensitivity at the current moment, R1+R2 is the resistance of the composite temperature sensor at the current moment, R1 is the resistance of the first temperature sensor at the current moment, R2 is the resistance of the second temperature sensor at the current moment, and T is the temperature at the current moment.

[0022] Preferably, the first temperature sensor uses a platinum resistance chip.

[0023] Preferably, the second temperature sensor uses a ceramic carbon resistor chip.

[0024] By applying the technical solution of this invention, two low-cost temperature sensor chips are simultaneously encapsulated and connected in series within a composite temperature sensor. The temperature-resistance curves of the two chips are opposite, and the composite temperature sensor extends to three measurement points. Based on the sensitivity at the current moment, the excitation current is switched for the next moment to always provide a suitable detection voltage, avoiding excessively high or low voltage. Simultaneously, based on the sensitivity at the current moment, the voltage signal detection point is switched to always provide good sensor sensitivity. This invention exhibits good measurement sensitivity at low (4K), medium (77K), and high (350K) temperatures, and is applicable across the entire temperature range. Attached Figure Description

[0025] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0026] Figure 1 A flowchart of a temperature detection method using a composite temperature sensor according to an embodiment of the present invention is shown.

[0027] Figure 2 A circuit diagram of a composite temperature sensor according to an embodiment of the present invention is shown. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] like Figure 1 As shown, the present invention provides a temperature detection method using a composite temperature sensor, the method comprising:

[0032] S10. Electrically connect the second terminal of the first temperature sensor and the first terminal of the second temperature sensor to achieve a series connection of the two temperature sensors, thereby forming a composite temperature sensor, such as... Figure 2 As shown; the first end of the first temperature sensor is taken as the first measurement point, the second end of the second temperature sensor is taken as the second measurement point, and the connection between the first temperature sensor and the second temperature sensor is taken as the third measurement point; wherein, the temperature-resistance curve of the first temperature sensor is a direct proportional coefficient, and the temperature-resistance curve of the second temperature sensor is an inverse proportional coefficient.

[0033] S20. Apply an initial excitation current to the composite temperature sensor, collect the resistance of the composite temperature sensor at the initial moment, and obtain the temperature at the initial moment based on the resistance of the composite temperature sensor at the initial moment; wherein, the initial excitation current is set to an arbitrary value; the resistance of the composite temperature sensor at the initial moment is the sum of the resistance values ​​of the first temperature sensor and the second temperature sensor.

[0034] S30. Based on the current resistance and temperature of the composite temperature sensor, the sensitivity of the composite temperature sensor at the current moment is obtained. If the sensitivity at the current moment is less than -X, the excitation current at the next moment is adjusted to the 10uA level, and the voltage between the second and third measurement points is collected as the detection signal of the composite temperature sensor at the next moment. If the sensitivity at the current moment is greater than X, the excitation current at the next moment is adjusted to the 1mA level, and the voltage between the first and third measurement points is collected as the detection signal of the composite temperature sensor at the next moment. If the absolute value of the sensitivity at the current moment is less than or equal to X, the excitation current at the next moment is adjusted to the 100uA level, and the voltage between the first and second measurement points is collected as the detection signal of the composite temperature sensor at the next moment. Wherein, X is the preset sensitivity.

[0035] S40. Divide the detection signal of the composite temperature sensor at the next moment by the excitation current at the next moment and use the result as the resistance of the composite temperature sensor at the next moment.

[0036] S50. Obtain the temperature at the next moment based on the resistance of the composite temperature sensor at the next moment;

[0037] S60, repeat S30~S50 to complete the temperature detection at each subsequent time.

[0038] In this invention, such as Figure 2 As shown, the composite temperature sensor consists of two temperature sensors, R1 and R2, with different parameter characteristics. Both R1 and R2 are electrodeless temperature sensors, each with two signal detection points, neither of which is polarity-sensitive. R1 and R2 are connected in series, and the remaining two measurement points (a and b) become the new positive and negative measurement points of the composite temperature sensor. A third measurement point (c) is led out from the connection point of the two temperature sensors. Measurement points a and b are not strictly polarity-sensitive and can be interchanged.

[0039] Furthermore, the R1 temperature sensor chip provides a good resistance slope for the composite temperature sensor in the high-temperature range (77K~350K). Therefore, a common sensor model suitable for high-temperature detection should be selected for R1, and its temperature-resistance curve should have a direct proportionality coefficient (dR1 / dT>0). Generally, a PT100 platinum resistance chip can be used. The R2 temperature sensor chip provides a good resistance slope for the composite temperature sensor in the low-temperature range (4K~77K). Therefore, a common sensor model suitable for low-temperature detection should be selected for R2, and its temperature-resistance curve should have an inverse proportionality coefficient (dR2 / dT<0). Generally, a TVO ceramic carbon resistance chip can be used.

[0040] Furthermore, during the cooling process in the low-temperature range (4K~77K), the resistance of the R1 temperature sensor chip gradually decreases from less than 10Ω (dR1 / dT≈0), while the resistance of the R2 temperature sensor chip gradually increases to the 1000Ω level (dR2 / dT is relatively large). Therefore, the resistance characteristics in this range are mainly provided by the R2 temperature sensor, which provides good sensitivity characteristics for low-temperature range measurements.

[0041] During the heating process in the high-temperature range (77K~350K), the resistance of the R2 temperature sensor chip gradually decreases from less than 100Ω (dR2 / dT≈0), while the resistance of the R1 temperature sensor chip gradually increases to the 100Ω level (dR1 / dT is relatively large). Therefore, the resistance characteristics in this range are mainly provided by the R1 temperature sensor, which provides good sensitivity characteristics for high-temperature range measurements.

[0042] In addition, in order to ensure that the two temperature sensor chips have an appropriate excitation current in their respective advantageous temperature ranges to achieve the best measurement results, the excitation current is switched in real time according to the rate of change of R1+R2.

[0043] (1) d(R1+R2) / dT<-X, excitation current is in the 10uA range;

[0044] (2) d(R1+R2) / dT>+X, excitation current is in the 1mA range;

[0045] (3) |d(R1+R2) / dT|≤X, excitation current level 100uA.

[0046] Generally, the preset sensitivity X is set to 1Ω / K.

[0047] To ensure a relatively ideal resistance measurement accuracy during testing, a high-sensitivity chip should be selected as the voltage detection target to obtain better sensor sensitivity.

[0048] (1) d(R1+R2) / dT<-X, Ubc is used as the composite sensor to detect the signal;

[0049] (2) d(R1+R2) / dT>+X, Uac is used as the composite sensor to detect the signal;

[0050] (3) |d(R1+R2) / dT|≤X, Uab is used as the composite sensor to detect the signal.

[0051] In summary, this invention provides a temperature detection method using a composite temperature sensor. By simultaneously encapsulating two low-cost temperature sensor chips in series within the composite temperature sensor, and with the two chips exhibiting opposite temperature-resistance curves, the composite temperature sensor generates three measurement points. Based on the current sensitivity, the excitation current is switched for the next moment to consistently provide a suitable detection voltage, avoiding excessively high or low voltage. Simultaneously, based on the current sensitivity, the voltage signal detection point is switched to consistently provide good sensor sensitivity. This invention exhibits good measurement sensitivity at low (4K), medium (77K), and high (350K) temperatures, and is applicable across the entire temperature range.

[0052] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0053] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A temperature detection method using a composite temperature sensor, characterized in that, The method includes: S10. Electrically connect the second end of the first temperature sensor and the first end of the second temperature sensor to realize the series connection of the two temperature sensors, thereby forming a composite temperature sensor; take the first end of the first temperature sensor as the first measurement point, the second end of the second temperature sensor as the second measurement point, and the connection point between the first temperature sensor and the second temperature sensor as the third measurement point; wherein, the temperature-resistance curve of the first temperature sensor is a direct proportional coefficient, and the temperature-resistance curve of the second temperature sensor is an inverse proportional coefficient. S20. Apply an initial excitation current to the composite temperature sensor, collect the resistance of the composite temperature sensor at the initial moment, and obtain the temperature at the initial moment based on the resistance of the composite temperature sensor at the initial moment; wherein, the initial excitation current is set to an arbitrary value; the resistance of the composite temperature sensor at the initial moment is the sum of the resistance values ​​of the first temperature sensor and the second temperature sensor. S30. Based on the current resistance and temperature of the composite temperature sensor, the sensitivity of the composite temperature sensor at the current moment is obtained. If the sensitivity at the current moment is less than -X, the excitation current at the next moment is adjusted to the 10uA level, and the voltage between the second and third measurement points is collected as the detection signal of the composite temperature sensor at the next moment. If the sensitivity at the current moment is greater than X, the excitation current at the next moment is adjusted to the 1mA level, and the voltage between the first and third measurement points is collected as the detection signal of the composite temperature sensor at the next moment. If the absolute value of the sensitivity at the current moment is less than or equal to X, the excitation current at the next moment is adjusted to the 100uA level, and the voltage between the first and second measurement points is collected as the detection signal of the composite temperature sensor at the next moment. Wherein, X is the preset sensitivity. S40. Divide the detection signal of the composite temperature sensor at the next moment by the excitation current at the next moment and use the result as the resistance of the composite temperature sensor at the next moment. S50. Obtain the temperature at the next moment based on the resistance of the composite temperature sensor at the next moment; S60, repeat S30~S50 to complete the temperature detection at each subsequent time.

2. The method according to claim 1, characterized in that, During the cooling process in the low-temperature range, the resistance of the first temperature sensor gradually decreases from less than 10Ω, while the resistance of the second temperature sensor gradually increases to the level of 1000Ω; during the heating process in the high-temperature range, the resistance of the second temperature sensor gradually decreases from less than 100Ω, while the resistance of the first temperature sensor gradually increases to the level of 100Ω.

3. The method according to claim 1, characterized in that, The temperature range of the low-temperature range is 4K to 77K, and the temperature range of the high-temperature range is 77K to 350K.

4. The method according to claim 1, characterized in that, The sensitivity of the composite temperature sensor at the current moment can be obtained using the following formula: D = d(R1 + R2) / dT In the formula, D is the sensitivity at the current moment, R1+R2 is the resistance of the composite temperature sensor at the current moment, R1 is the resistance of the first temperature sensor at the current moment, R2 is the resistance of the second temperature sensor at the current moment, and T is the temperature at the current moment.

5. The method according to any one of claims 1-4, characterized in that, The first temperature sensor uses a platinum resistance chip.

6. The method according to any one of claims 1-5, characterized in that, The second temperature sensor uses a ceramic carbon resistor chip.

Images