Temperature drift compensation method and system for Stirling cryocooler controller

Abstract

The invention discloses a temperature drift compensation method for a Stirling cryocooler controller, and the method comprises the steps: building a compensation function: T is an actual refrigeration temperature, Te is an environment temperature, and k1, k2, k3,..., kn + 1 are compensation coefficients; s120, n + 1 environment temperatures Te and n + 1 actual refrigeration temperature data T in one-to-one correspondence with the environment temperatures Te are obtained, and the value of a compensation coefficient is calculated; and S130, the environment temperature Te is obtained in real time, the actual refrigeration temperature T is calculated, and the refrigeration temperature of the controller is corrected according to the actual refrigeration temperature. By establishing the compensation function and calculating the compensation coefficient in the compensation function, the refrigerating temperature of the controller can be corrected in real time according to the environment temperature in the using process of the controller, and therefore it is ensured that the refrigerating temperature of the controller is accurate. And meanwhile, temperature drift compensation is carried out on the controller, so that the qualified controller does not need to be screened through an experiment, and a large amount of resource waste is avoided. The invention further discloses a temperature drift compensation system of the Stirling cryocooler controller.

Description

Technical Field

[0001] This application belongs to the field of controller temperature drift compensation technology, specifically relating to a method and system for temperature drift compensation of a Stirling refrigerator controller. Background Technology

[0002] A Stirling cryostat is an ultra-low temperature refrigeration device commonly used to produce liquid nitrogen temperatures (77K) or even deep cryogenic temperatures (below 10K). Therefore, this device is widely used in military, aerospace, superconductivity, infrared detection, and guidance fields. During application, the voltage reference source inside the ADC chip shifts when the ambient temperature changes significantly. This causes fluctuations in the operating temperature of the detector provided by the Stirling cryostat's cold head, known as controller temperature drift. For short-wave and mid-wave detector chips, a temperature drift of ±0.5K or more can cause skewing interference and image jitter in the imaging; for long-wave detectors, the operating conditions are even more demanding, with a temperature drift exceeding ±0.15K leading to a decrease in image quality. This deterioration in imaging quality not only worsens the user experience but can even cause the infrared seeker to lose its target.

[0003] For Stirling refrigerators that generate an operating temperature of 77K, while most controllers can meet the environmental requirements of short- and mid-wave infrared detection chips, only a small number can meet the stringent requirements of long-wave detectors. Currently, most manufacturers screen and select qualified controllers through environmental testing, but this method results in a significant waste of resources. Summary of the Invention

[0004] The technical problem this application aims to solve is that the current method of selecting qualified controllers through experiments results in a large waste of resources. To solve this problem, this application provides a method and system for compensating the temperature drift of a Stirling refrigerator controller, which can compensate for the temperature drift of the controller and enable the controller to meet the requirements of the working environment.

[0005] The technical solution proposed in this application is as follows: A method for temperature drift compensation in a Stirling refrigerator controller includes the following steps: S110, Establish the compensation function: Where T is the actual cooling temperature, T e Let k1, k2, k3, ..., k be the ambient temperature. n+1 The compensation coefficient; S120, obtain n+1 ambient temperatures T e and the relationship with ambient temperature T e The compensation coefficient is calculated by substituting the values ​​of n+1 actual cooling temperature data T into the compensation function. S130, real-time acquisition of ambient temperature Te The ambient temperature T e Substitute the values ​​into the compensation function to calculate the actual cooling temperature T, and then correct the controller's cooling temperature based on the actual cooling temperature.

[0006] By employing the aforementioned temperature drift compensation method for Stirling refrigerator controllers, a compensation function is established and the compensation coefficients within it are calculated. This allows the controller to adjust its cooling temperature in real-time based on the ambient temperature during operation, ensuring accurate cooling. Furthermore, by compensating for temperature drift, experimental screening of qualified controllers is eliminated, preventing significant resource waste.

[0007] Furthermore, S110 includes the following steps: S111, place the Stirling refrigerator inside the incubator; S112, control the ambient temperature inside the temperature chamber to gradually increase from a first preset temperature to a second preset temperature with equal time and temperature gradients, and acquire multiple ambient temperatures T. e and the relationship with ambient temperature T e The actual cooling temperature T that corresponds one-to-one; S113, with ambient temperature T e A coordinate system is established with the ambient temperature T as the horizontal axis and the actual cooling temperature T as the vertical axis. A curve showing the relationship between the ambient temperature and the actual cooling temperature is plotted based on the data obtained in S112. S114, Fit the curve to obtain the compensation function.

[0008] Furthermore, the S111 contains multiple Stirling refrigerators.

[0009] Furthermore, S110 also includes: S115. Replace with other functions and compare the fitted curve with the actual data to verify the accuracy of the compensation function.

[0010] Furthermore, in S115, the residuals, mean square error, and R² of the fitted curve and the actual data are compared.

[0011] Furthermore, S120 also includes the following steps: S121, determine the value of n; S122, obtain n+1 ambient temperatures T e and the relationship with ambient temperature T e A one-to-one correspondence of n+1 actual cooling temperature data T; S123, Substitute the numerical values ​​into the compensation function to calculate the value of the compensation coefficient; S124 stores the compensation function and compensation coefficients.

[0012] Furthermore, in S130, through the formula: Correct the controller's cooling temperature, where T a The corrected controller cooling temperature, T b The original controller cooling temperature.

[0013] A temperature drift compensation system for a Stirling refrigerator controller includes: An incubator is used to house a Stirling refrigerator and to regulate the ambient temperature of the Stirling refrigerator. A temperature sensor is installed in the temperature chamber to detect the ambient temperature; The host computer and the constant current source are both connected to the temperature measuring diode inside the Stirling refrigerator. The host computer is also connected to the temperature chamber, the temperature sensor and the Stirling refrigerator controller.

[0014] Furthermore, it also includes a correction card module, the host computer is connected to the correction card module, and the correction card module is connected to multiple Stirling refrigerator controllers.

[0015] In summary, the temperature compensation method and system for Stirling refrigerators provided in this application have at least one of the following advantages: 1. By establishing a compensation function to correct the cooling temperature of the controller, the cooling temperature of the controller is ensured to be accurate, eliminating the need for experimental screening of qualified controllers and avoiding a large waste of resources. 2. It can correct multiple controllers at once, improving operational efficiency. Attached Figure Description

[0016] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0017] Figure 1 A flowchart of a temperature drift compensation method for Stirling refrigerator control provided in an embodiment of this application. Detailed Implementation

[0018] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0019] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0024] To facilitate understanding of the technical solution of this application, the temperature drift problem of existing Stirling refrigerator controllers used to generate a 77K low-temperature operating temperature is explained here: The temperature drift phenomenon of existing Stirling refrigerator controllers is mainly manifested in the controller's control temperature changing with the ambient temperature. The root cause is that the reference voltage source inside the ADC sampling chip used in the controller drifts with changes in ambient temperature. This drift characteristic is fixed and highly correlated with the individual controller. For example, when a Stirling refrigerator generates a 77K operating temperature, after the temperature stabilizes, the controller determines that the operating temperature of 77K has been reached. However, due to the influence of the ambient temperature, the controller exhibits temperature drift, resulting in an actual cooling temperature of 76K. Because the drift characteristic is fixed, the controller's cooling temperature can be corrected to 78K under the current ambient temperature, thereby correcting the actual cooling temperature to 77K.

[0025] On one hand, this application provides a temperature drift compensation method for a Stirling refrigerator controller, which can compensate for the temperature drift of a Stirling refrigerator that generates an operating temperature of 77K. Of course, the Stirling refrigerator can also generate other operating temperatures as needed, such as operating temperatures below 10K. It should be noted that the operating temperature of the Stirling refrigerator in this application is known, and the temperature drift compensation method is based on this known operating temperature.

[0026] like Figure 1 As shown, the temperature drift compensation method includes the following steps: S110, Establish the compensation function: Where T is the actual cooling temperature, T e Let k1, k2, k3, ..., k be the ambient temperature. n+1 This is the compensation coefficient. S120, obtain n+1 ambient temperatures T. e and the relationship with ambient temperature T e The n+1 corresponding actual cooling temperature data T are used to calculate the compensation coefficient by substituting the values ​​into the compensation function. S130, real-time acquisition of ambient temperature T. e The ambient temperature T e Substitute the values ​​into the compensation function to calculate the actual cooling temperature T, and then correct the controller's cooling temperature based on the actual cooling temperature.

[0027] In other words, this compensation method first establishes a compensation function to compensate for the temperature drift of the controller under different ambient temperatures. Then, it calculates the compensation coefficient in the compensation function based on the measured ambient temperature and the actual cooling temperature. Finally, it stores the compensation function and the compensation coefficient in the controller. Subsequently, the controller can correct the controller cooling temperature in real time according to the ambient temperature to ensure the accuracy of the controller cooling temperature and improve the imaging quality of the infrared detector.

[0028] By employing the aforementioned temperature drift compensation method for Stirling refrigerator controllers, a compensation function is established and the compensation coefficients within it are calculated. This allows the controller to adjust its cooling temperature in real-time based on the ambient temperature during operation, ensuring accurate cooling. Furthermore, by compensating for temperature drift, experimental screening of qualified controllers is eliminated, preventing significant resource waste.

[0029] It should be explained that the ambient temperature mentioned above can be obtained through a temperature sensor, and the actual cooling temperature can be obtained by connecting a constant current source to the temperature sensing diode inside the Stirling refrigerator. This provides the excitation current for the diode to operate normally and detects the real-time PN junction voltage of the diode. Then, the host computer is connected to the temperature sensing diode, for example, through an AD converter, so that the host computer can obtain the actual cooling temperature in real time.

[0030] In one embodiment, S110 includes the steps of: S111, placing the Stirling refrigerator inside a temperature chamber; and S112, controlling the ambient temperature inside the temperature chamber to gradually increase from a first preset temperature to a second preset temperature with equal time and temperature gradients, and acquiring multiple ambient temperatures T. e and the relationship with ambient temperature T e The actual cooling temperature T corresponds one-to-one with S113, based on the ambient temperature T. e A coordinate system is established with ambient temperature T as the horizontal axis and actual cooling temperature T as the vertical axis. A curve showing the relationship between ambient temperature and actual cooling temperature is plotted based on the data obtained in S112. In S114, the curve is fitted to obtain a compensation function.

[0031] It should be explained that in S111, the temperature chamber can regulate the ambient temperature of the Stirling refrigerator. Furthermore, in this step, multiple Stirling refrigerators are placed in the temperature chamber, meaning multiple Stirling refrigerator controllers are corrected simultaneously, improving correction efficiency. In S112, a temperature sensor can be installed inside the temperature chamber to obtain the ambient temperature inside the chamber, i.e., the ambient temperature of the Stirling refrigerator. The actual cooling temperature is obtained as described above. For obtaining multiple ambient temperatures and multiple actual cooling temperatures, assuming the ambient temperature is raised from -55℃ (218.15K) to 70℃ (343.15K), increasing the ambient temperature by 5℃ every ten minutes, other heating methods and ranges can also be used, without limitation. Simultaneously, after each instance of the ambient temperature and the cold screen temperature of the Stirling refrigerator stabilizing, the ambient temperature and the actual cooling temperature are measured, thus obtaining multiple corresponding ambient temperatures and multiple actual cooling temperatures.

[0032] In S113 and S114, curve plotting and fitting can be performed using existing technologies, such as using tools like MATLAB or Python to plot the ambient temperature-actual cooling temperature curve and then using these tools to fit the curve to obtain the aforementioned compensation function.

[0033] In one embodiment, S120 includes the steps of: S121, determining the value of n; and S122, acquiring n+1 ambient temperatures T. e and the relationship with ambient temperature T e S123: Substitute the values ​​into the compensation function to calculate the compensation coefficient; S124: Store the compensation function and compensation coefficient.

[0034] It needs to be explained that for S121, after curve fitting, the linearity of the compensation function can be determined. At this point, it is necessary to determine the number of compensation coefficients in the compensation function, i.e., to determine the value of n, and then the value of n+1. The number of compensation coefficients needs to be determined based on the allowable value of temperature drift error, controller performance, and the variance between the model and the actual curve. For example, the more compensation coefficients there are, the higher the accuracy of temperature drift compensation, but the computational load will increase. Therefore, the controller performance will limit the number of compensation coefficients. For example, the compensation parameter can be determined as follows: The value of n is 3, and the number of compensation coefficients is 4.

[0035] For S122 and S123, based on the above description, it can be determined that the compensation function is... For example, to calculate the compensation coefficient, at least four sets of ambient temperature and actual cooling temperature data are required. After the compensation coefficient is calculated, as described in S124, the compensation function and compensation coefficient are stored, specifically in the Stirling refrigerator controller. The controller can then directly call the compensation function and corresponding compensation coefficient to calculate the actual cooling temperature based on the ambient temperature.

[0036] In one embodiment, S130 uses the following formula: Correct the controller's cooling temperature, where T a The corrected controller cooling temperature, T b This represents the controller's cooling temperature before correction. It is understandable that in this formula, To correct the difference between the original controller cooling temperature and the actual cooling temperature, a temperature drift value is used to adjust the controller cooling temperature. Taking a 77K operating temperature as an example, if the original controller cooling temperature is 77K and the actual cooling temperature is 76K, the temperature drift value is 1K. The actual cooling temperature is 1K lower. By adding the temperature drift value to the original controller cooling temperature, the controller cooling temperature is corrected to 78K, corresponding to an actual cooling temperature of 77K.

[0037] On the other hand, based on the temperature drift compensation method of the Stirling refrigerator controller in the above embodiments, this application also provides a temperature drift compensation system for the Stirling refrigerator controller that can perform the above temperature drift compensation method in real time.

[0038] In one embodiment, the temperature drift compensation system includes a temperature chamber, a temperature sensor, a host computer, and a constant current source. The temperature chamber houses the Stirling refrigerator and regulates the ambient temperature of the Stirling refrigerator; specifically, as described above, it can control the ambient temperature to gradually increase from a first preset temperature to a second preset temperature with equal time and temperature gradients. The temperature sensor is located in the temperature chamber to detect the ambient temperature, thereby acquiring multiple ambient temperature data points during the heating process.

[0039] Both the host computer and the constant current source are connected to the temperature-sensing diode inside the Stirling refrigerator. The host computer can be a computer or other control unit with a touch screen. The constant current source provides excitation current to the temperature-sensing diode and detects the PN junction voltage of the diode. The detected data is then input into the host computer, which calculates the actual cooling temperature of the Stirling refrigerator. Simultaneously, the host computer is also connected to the Stirling refrigerator's controller, temperature chamber, and temperature sensors. The host computer can control the temperature chamber to perform gradient heating, then acquire two sets of data: ambient temperature and actual cooling temperature. After acquiring the data, a relationship curve is plotted, and curve fitting is performed. The compensation function's linearity is then determined and verified, and the number of compensation coefficients in the compensation function can be determined based on requirements and controller performance. Next, the host computer inputs the compensation function, multiple ambient temperature data points, and multiple actual cooling temperature data points into the controller. The controller calculates the compensation coefficients and saves the compensation function and the calculated compensation coefficients. Next, the host computer sends a correction command to the controller and sends the ambient temperature data to the controller in real time. The controller calls the compensation function to calculate the actual cooling temperature and corrects the controller's cooling temperature according to the actual cooling temperature and the formula in S130.

[0040] It should be further explained that this compensation method and system primarily correct for the ambient temperatures experienced during the application of the Stirling refrigerator. In actual Stirling refrigerator operation, if other ambient temperatures occur due to temperature anomalies, the ambient temperature will be detected by a temperature sensor. Simultaneously, a host computer will acquire the ambient temperature data and send it to the controller. Specifically, after determining that the ambient temperature is abnormal, the host computer first sends a correction command to the controller, then sends the ambient temperature data to the controller. The controller calls the compensation function and compensation coefficients, calculates the actual cooling temperature based on the ambient temperature, and then corrects the controller's cooling temperature according to the formula in S130.

[0041] In one embodiment, the temperature drift compensation system further includes a correction card module. A host computer connects to the correction card module, which can connect to multiple Stirling refrigerator controllers. This allows for simultaneous correction of multiple controllers, or individual correction of each controller, eliminating the need for frequent testing and improving efficiency.

[0042] In summary, the temperature compensation method and system for Stirling refrigerators provided in this application have at least one of the following advantages: 1. By establishing a compensation function to correct the cooling temperature of the controller, the cooling temperature of the controller is ensured to be accurate, eliminating the need for experimental screening of qualified controllers and avoiding a large waste of resources. 2. It can correct multiple controllers at once, improving operational efficiency.

[0043] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for compensating for temperature drift in a Stirling refrigerator controller, characterized in that, Including the following steps: S110, Establish the compensation function: Where T is the actual cooling temperature, T e Let k1, k2, k3, ..., k be the ambient temperature. n+1 The compensation coefficient; S120, obtain n+1 ambient temperatures T e and the relationship with ambient temperature T e The compensation coefficient is calculated by substituting the values ​​of n+1 actual cooling temperature data T into the compensation function. S130, real-time acquisition of ambient temperature T e The ambient temperature T e Substitute the values ​​into the compensation function to calculate the actual cooling temperature T, and then correct the controller's cooling temperature based on the actual cooling temperature.

2. The temperature drift compensation method for the Stirling refrigerator controller according to claim 1, characterized in that, S110 includes the following steps: S111, place the Stirling refrigerator inside the incubator; S112, control the ambient temperature inside the temperature chamber to gradually increase from a first preset temperature to a second preset temperature with equal time and temperature gradients, and acquire multiple ambient temperatures T. e and the relationship with ambient temperature T e The actual cooling temperature T that corresponds one-to-one; S113, with ambient temperature T e A coordinate system is established with the ambient temperature T as the horizontal axis and the actual cooling temperature T as the vertical axis. A curve showing the relationship between the ambient temperature and the actual cooling temperature is plotted based on the data obtained in S112. S114, Fit the curve to obtain the compensation function.

3. The temperature drift compensation method for the Stirling refrigerator controller according to claim 2, characterized in that, The S111 contains multiple Stirling refrigerators.

4. The temperature drift compensation method for the Stirling refrigerator controller according to claim 2, characterized in that, S110 also includes: S115. Replace with other functions and compare the fitted curve with the actual data to verify the accuracy of the compensation function.

5. The temperature drift compensation method for the Stirling refrigerator controller according to claim 4, characterized in that, In S115, the residuals, mean square error, and R² of the fitted curve and the actual data are compared.

6. The temperature drift compensation method for a Stirling refrigerator controller according to claim 1, characterized in that, S120 also includes the following steps: S121, determine the value of n; S122, obtain n+1 ambient temperatures T e and the relationship with ambient temperature T e A one-to-one correspondence of n+1 actual cooling temperature data T; S123, Substitute the numerical values ​​into the compensation function to calculate the value of the compensation coefficient; S124 stores the compensation function and compensation coefficients.

7. The temperature drift compensation method for the Stirling refrigerator controller according to claim 1, characterized in that, In S130, by formula: Correct the controller's cooling temperature, where T a The corrected controller cooling temperature, T b The original controller cooling temperature.

8. A temperature drift compensation system for a Stirling refrigerator controller, characterized in that, include: An incubator is used to house a Stirling refrigerator and to regulate the ambient temperature of the Stirling refrigerator. A temperature sensor is installed in the temperature chamber to detect the ambient temperature; The host computer and the constant current source are both connected to the temperature sensing diode inside the Stirling refrigerator. The host computer is also connected to the temperature sensor and the Stirling refrigerator controller.

9. The temperature drift compensation system for the Stirling refrigerator controller according to claim 8, characterized in that, It also includes a correction card module, the host computer is connected to the correction card module, and the correction card module is connected to multiple Stirling refrigerator controllers.

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