Shell temperature control method of large-power-consumption spacecraft in life evaluation test

Abstract

The invention discloses a shell temperature control method for a high-power-consumption spacecraft in a life evaluation test. The method comprises the following steps: determining heating power required by a heating resistor according to characteristics of the high-power-consumption spacecraft and an expected shell temperature during the life evaluation test; selecting the type and parameters of a heating resistor according to the required heating power, and determining the resistance value; determining power supply voltage required by the heating resistor according to the heating power and the resistance value; the heating resistor is fixedly installed on a shell of the large-power-consumption spacecraft part; and when the service life evaluation test is carried out on the large-power-consumption spacecraft part, the heating resistor is powered by the required power supply voltage. According to the method, the shell temperature of the large-power-consumption spacecraft in the life evaluation test process can be effectively controlled, so that the influence rule of thermal stress on key characteristic parameters of the device is explored in the life evaluation test, the service life of the large-power-consumption spacecraft in the space irradiation environment is predicted, and the design or process weak points of the large-power-consumption spacecraft are identified; and support is provided for improvement of large-power-consumption spacecraft parts.

Description

Technical Field

[0001] The present invention belongs to the field of device life assessment, and in particular relates to a shell temperature control method for a high-power aerospace device in a life assessment test. Background Art

[0002] High-power aerospace components, such as DC / DC power supplies, typically possess the following characteristics: ① high performance and reliability; ② long service life; ③ large design margins, making reliability improvements difficult; and ④ high development costs. Given these characteristics, traditional lifespan evaluation methods are clearly unsuitable for lifespan assessment testing of high-power aerospace components like DC / DC power supplies. These tests typically operate under normal stress levels. While the resulting product reliability is relatively close to realistic levels, the data acquisition process requires long testing times and high costs. This is unacceptable for high-power aerospace components, such as DC / DC power supplies, which require high reliability and long lifespans. More efficient accelerated stress lifespan evaluation methods are essential. Currently, scholars and research institutions at home and abroad have conducted extensive research on the aging effects and lifespan prediction techniques for DC / DC power supplies, but a more scientific method for controlling case temperature has yet to be reported. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a shell temperature control method for a high-power aerospace device in a life assessment test.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A method for controlling the shell temperature of a high-power aerospace device during a life assessment test comprises the following steps:

[0006] S100. Determine the heating power required by the heating resistor based on the characteristics of the high-power aerospace device and the expected shell temperature during the life assessment test;

[0007] S200, selecting the type and parameters of the heating resistor according to the heating power required by the heating resistor, and determining the resistance value;

[0008] S300, determining the power supply voltage required by the heating resistor according to the heating power and resistance of the heating resistor;

[0009] S400, install and fix the heating resistor on the housing of the high-power aerospace component;

[0010] S500. When conducting life assessment tests on high-power aerospace components, power the heating resistor with the required supply voltage.

[0011] Furthermore, the step S100 includes the following sub-steps:

[0012] S110. Calculate the equivalent power P of the heat dissipation characteristics of high-power aerospace components H ;

[0013] S120. Calculate the equivalent power P at ambient temperature based on the shell temperature expected to be maintained during the life assessment test of high-power aerospace components. e ;

[0014] S130, equivalent power P based on heat dissipation characteristics H Equivalent power P with ambient temperature e The sum is the heating power P required by the heating resistor R .

[0015] Furthermore, the equivalent power P of the heat dissipation characteristic H The calculation formula is:

[0016] P H =hAΔT

[0017] Wherein, h represents the natural convection heat transfer coefficient; A represents the heat dissipation surface area of ​​the shell of the high-power aerospace device; ΔT represents the difference between the shell temperature of the high-power aerospace device and the ambient temperature.

[0018] Furthermore, the equivalent power P of the heat dissipation characteristic H The calculation formula is:

[0019] Equivalent power P at ambient temperature e The calculation formula is:

[0020]

[0021] Wherein, ε represents the surface emissivity of the shell of the high-power aerospace device; σ represents the Stefan-Boltzmann constant; A represents the heat dissipation surface area of ​​the shell of the high-power aerospace device; T s It represents the expected shell temperature of high power consumption aerospace components during life assessment test; T e Indicates the ambient temperature.

[0022] Furthermore, in the step S200, a resistor having a rated power greater than the heating power required by the heating resistor and a small temperature coefficient is selected as the heating resistor.

[0023] Furthermore, in the step S200, a precision metal film resistor is selected as the heating resistor.

[0024] Furthermore, in the step S400, a compression structure is used to fix and compress the heating resistor at the four corners of the housing of the high-power aerospace component; or

[0025] Use thermal conductive adhesive to evenly stick the heating resistor on the shell surface of the high-power aerospace device.

[0026] Furthermore, in the step S400, a voltage stabilizing diode is connected in parallel across the two ends of the heating resistor, and the voltage stabilizing diode limits the maximum operating voltage of the heating resistor; or

[0027] The heating resistor is connected in series with a current limiting resistor, and the maximum operating current of the heating resistor is limited by the current limiting resistor.

[0028] Furthermore, in the step S100, the expected shell temperature during the life assessment test of the high-power aerospace device is in a range. In the step S500, a constant voltage source is used to provide a stable power supply voltage for the heating resistor, and when the shell temperature of the high-power aerospace device exceeds the expected shell temperature range, the voltage of the constant voltage source is adjusted accordingly.

[0029] Furthermore, the high-power consumption aerospace device is a DC / DC power supply, an LDO or an operational amplifier.

[0030] The present invention can effectively control the shell temperature of high-power aerospace devices during life assessment tests, and can be used in life assessment tests to explore the influence of thermal stress on key characteristic parameters of devices, predict the service life of high-power aerospace devices under space radiation environments, identify design or process weaknesses of high-power aerospace devices, and provide support for the improvement of high-power aerospace devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 The present invention is a flowchart of an embodiment of a method for controlling the shell temperature of a high-power aerospace device in a life assessment test.

[0033] Figure 2 Flowchart for determining the heating power required by the heating resistor. DETAILED DESCRIPTION

[0034] The following describes the implementation of the present invention through specific examples. The illustrations provided in the following embodiments are only used to schematically illustrate the basic concept of the present invention. The following embodiments and features in the embodiments may be combined with each other unless there is any conflict.

[0035] Mutual diffusion is the most basic characteristic of various conductive materials. Due to different material properties, the diffusion rate will also be different - the higher the temperature, the faster the diffusion rate of various materials, and the greater the difference in diffusion rate. In this way, as time goes on, it will also cause problems with the continuity of the contact surface, resulting in problems such as void accumulation. This phenomenon is called thermal migration. Taking aerospace DC / DC power supplies as an example, the two main factors affecting thermal migration are material properties and temperature. The influence of temperature is absolute, and the increase in the internal junction temperature of aerospace DC / DC power supplies will lead to increased thermal migration, which can clarify the impact of thermal stress on aerospace DC / DC power supplies. The shell temperature of aerospace DC / DC power supplies can intuitively reflect the changes in its internal junction temperature. Therefore, the life assessment test of aerospace DC / DC power supplies requires monitoring and controlling the shell temperature. Thermal stress is proportional to the change in temperature. At this time, the failure time TTF of aerospace DC / DC power supplies can be expressed as the following formula:

[0036]

[0037] Wherein, T0 represents a constant related to the material, which can be obtained by fitting the accelerated life test (ALT) data; T0 represents the stress-free temperature of the metal (for aluminum, it is approximately equal to the metal deposition temperature); E a represents the activation energy, which is 0.5eV~0.6eV for grain boundary diffusion and 1.2eV~1.4eV for intra-grain diffusion only; k represents the Boltzmann constant; T represents the absolute temperature.

[0038] To quickly assess the reliable lifespan characteristics and performance changes of aerospace DC / DC power supplies, increasing the test temperature is often used to accelerate product failure and shorten test time. The aging effects of DC / DC power supplies during storage are studied under varying temperature stress conditions. This testing method primarily accelerates the product's failure process by increasing the product's operating stress, thereby providing a relatively short prediction of the product's lifespan under actual operational stress levels. However, the test environment temperature does not represent the actual case temperature of aerospace DC / DC power supplies, necessitating the solution to maintain a stable case temperature within the required research range.

[0039] See also Figure 1 , Figure 1 This is a flow chart of an embodiment of a method for controlling the shell temperature of a high-power aerospace device during a life assessment test. The following uses a DC / DC power supply for aerospace as an example. The method for controlling the shell temperature of a high-power aerospace device during a life assessment test in this embodiment includes the following steps:

[0040] S100. Determine the heating power P required by the heating resistor based on the characteristics of the aerospace DC / DC power supply (i.e., high-power aerospace components) and the expected shell temperature during the life assessment test. RSee Figure 2 , this step may include the following sub-steps:

[0041] S110. Calculate the equivalent power P of the heat dissipation characteristics of aerospace DC / DC power supplies H In this embodiment, natural convection heat dissipation is used as an example to calculate the equivalent power P of the heat dissipation characteristics. H , the calculation formula is as follows:

[0042] P H =hAΔT

[0043] Where h represents the natural convection heat transfer coefficient; A represents the heat dissipation surface area of ​​the aerospace DC / DC power supply housing; and ΔT represents the difference between the housing temperature of the aerospace DC / DC power supply and the ambient temperature.

[0044] S120. Calculate the equivalent power P at ambient temperature based on the shell temperature expected to be maintained during the life assessment test of the aerospace DC / DC power supply. e In this embodiment, the equivalent power P of the heat dissipation characteristic is calculated by taking radiation heat dissipation as an example. H , the calculation formula is as follows:

[0045]

[0046] Where, ε represents the surface emissivity of the shell of the aerospace DC / DC power supply; σ represents the Stefan-Boltzmann constant; T s Indicates the expected case temperature of aerospace DC / DC power supply during life assessment test; T e Indicates the ambient temperature.

[0047] Since it is impossible to keep the shell temperature of aerospace DC / DC power supply precisely at one temperature during the life evaluation test, the shell temperature that the aerospace DC / DC power supply is expected to maintain during the life evaluation test can be a range, so as to calculate the equivalent power P at the corresponding ambient temperature. e interval.

[0048] S130, equivalent power P based on heat dissipation characteristics H Equivalent power P with ambient temperature e The sum is the heating power P required by the heating resistor R , the calculation formula is as follows:

[0049] P R =P H +P e

[0050] When the ambient temperature is equal to the equivalent power P e When it is an interval, the calculated heating power P R It is also an interval.

[0051] S200, select the type and parameters of the heating resistor according to the required heating power of the heating resistor, and determine the resistance R of the heating resistor. The resistance R of the heating resistor can be selected as needed to facilitate implementation. In this step, the rated power of the selected heating resistor must be greater than the required heating power P of the heating resistor calculated in the previous step. R , to meet the requirements of long-term stable heating operation and avoid damage due to overload. At the same time, it is also important to choose resistors with a small temperature coefficient to minimize the impact of temperature fluctuations on resistance, which in turn affects heating power. Testing has shown that precision metal film resistors offer the most stable performance in this regard. Therefore, after comprehensively considering resistance, power, and temperature coefficient, precision metal film resistors are used as the heating resistors in this embodiment.

[0052] S300, determining the power supply voltage U required by the heating resistor according to the heating power and resistance of the heating resistor. The power supply voltage U required by the heating resistor can be calculated according to the following formula:

[0053] P R =U 2 / R

[0054] Using the above formula to calculate the power supply voltage U required by the heating resistor, the heating power of the heating resistor can be just maintained at P calculated in the previous step. R .

[0055] S400: Install and secure the heating resistor to the housing of the aerospace DC / DC power supply. In this embodiment, a clamping structure is used at the four corners of the aerospace DC / DC power supply housing to secure and compress the heating resistor. Alternatively, thermally conductive adhesive can be used to evenly attach the heating resistor to the surface of the aerospace DC / DC power supply housing, or other securing methods can be employed. As long as the heating resistor maintains good contact with the housing surface, heat transfer efficiency will be improved.

[0056] In this embodiment, to prevent the heating resistor from being damaged due to overload, additional devices can be added to protect the heating resistor. For example, a voltage-stabilizing diode can be connected in parallel across the heating resistor to limit the maximum operating voltage of the heating resistor, thereby limiting the maximum heating power of the heating resistor and preventing it from exceeding the power of the heating resistor. Of course, a current-limiting resistor can also be connected in series with the circuit where the heating resistor is located to limit the maximum operating current of the heating resistor and thus limit the maximum heating power of the heating resistor.

[0057] S500. When performing a life assessment test on a DC / DC power supply for aerospace, the heating resistor is powered with the required power supply voltage. In this embodiment, a constant voltage source is used to provide a stable power supply voltage U for the heating resistor. Since in this embodiment, the expected shell temperature during the life assessment test of the DC / DC power supply for aerospace is a range, therefore, during the life assessment test, when the shell temperature of the DC / DC power supply for aerospace exceeds the expected shell temperature range, the output voltage of the constant voltage source can also be adjusted accordingly. For example, when the shell temperature of the DC / DC power supply for aerospace is lower than the expected shell temperature range, the output voltage of the constant voltage source can be increased accordingly; and when the shell temperature of the DC / DC power supply for aerospace is higher than the expected shell temperature range, the output voltage of the constant voltage source can be reduced accordingly to ensure that the shell temperature of the DC / DC power supply for aerospace remains within the expected shell temperature range, so as to avoid the shell temperature fluctuation of the DC / DC power supply for aerospace affecting the results of the life assessment test.

[0058] Of course, this embodiment is only described by taking the high-power aerospace device as a DC / DC power supply as an example. The method of this embodiment can also be extended to other high-power aerospace devices such as LDO or operational amplifier.

[0059] Experimental verification demonstrates that the method of this embodiment can effectively control the case temperature of aerospace DC / DC power supplies during life assessment testing. This method, when used in life assessment testing, can be used to investigate the impact of thermal stress on key power supply parameters, predict the service life of aerospace DC / DC power supplies under space radiation environments, and identify design or process weaknesses, providing support for improvements to aerospace DC / DC power supplies. Furthermore, this method can be extended to other devices, such as LDOs and op amps, and has broad application prospects.

[0060] The above embodiments merely represent preferred embodiments of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A shell temperature control method for a high-power aerospace device in a life assessment test, characterized in that: The following steps are involved: S100. Determine the heating power required by the heating resistor based on the characteristics of the high-power aerospace device and the expected shell temperature during the life assessment test; S200, selecting the type and parameters of the heating resistor according to the heating power required by the heating resistor, and determining the resistance value; S300, determining the power supply voltage required by the heating resistor according to the heating power and resistance of the heating resistor; S400, install and fix the heating resistor on the housing of the high-power aerospace component; S500. When conducting life assessment tests on high-power aerospace components, power the heating resistor with the required supply voltage.

2. The shell temperature control method for a high-power aerospace device in a life assessment test according to claim 1, characterized in that: The step S100 includes the following sub-steps: S110. Calculate the equivalent power P of the heat dissipation characteristics of high-power aerospace components H ; S120. Calculate the equivalent power P at ambient temperature based on the shell temperature expected to be maintained during the life assessment test of high-power aerospace components. e ; S130, equivalent power P based on heat dissipation characteristics H Equivalent power P with ambient temperature e The sum is the heating power P required by the heating resistor R .

3. The shell temperature control method for a high-power aerospace device in a life assessment test according to claim 2, characterized in that: Equivalent power P of heat dissipation characteristics H The calculation formula is: P H =hAΔT Wherein, h represents the natural convection heat transfer coefficient; A represents the heat dissipation surface area of ​​the shell of the high-power aerospace device; ΔT represents the difference between the shell temperature of the high-power aerospace device and the ambient temperature.

4. The shell temperature control method for a high-power aerospace device in a life assessment test according to claim 3, characterized in that: Equivalent power P of heat dissipation characteristics H The calculation formula is: Equivalent power P at ambient temperature e The calculation formula is: Wherein, ε represents the surface emissivity of the shell of the high-power aerospace device; σ represents the Stefan-Boltzmann constant; A represents the heat dissipation surface area of ​​the shell of the high-power aerospace device; T s It represents the expected shell temperature of high power consumption aerospace components during life assessment test; T e Indicates the ambient temperature.

5. The shell temperature control method for a high-power aerospace device in a life assessment test according to claim 1, characterized in that: In the step S200 , a resistor having a rated power greater than the heating power required by the heating resistor and a small temperature coefficient is selected as the heating resistor.

6. The shell temperature control method for a high-power aerospace device in a life assessment test according to claim 5, characterized in that: In the step S200 , a precision metal film resistor is selected as the heating resistor.

7. The shell temperature control method for a high-power aerospace device in a life assessment test according to any one of claims 1 to 6, characterized in that: In the step S400, a compression structure is used to fix and compress the heating resistor at the four corners of the housing of the high-power aerospace component; or Use thermal conductive adhesive to evenly stick the heating resistor on the shell surface of the high-power aerospace device.

8. The shell temperature control method for a high-power aerospace device in a life assessment test according to any one of claims 1 to 6, characterized in that: In the step S400, a voltage stabilizing diode is connected in parallel to both ends of the heating resistor, and the voltage stabilizing diode limits the maximum operating voltage of the heating resistor; or The heating resistor is connected in series with a current limiting resistor, and the maximum operating current of the heating resistor is limited by the current limiting resistor.

9. The shell temperature control method for a high-power aerospace device in a life assessment test according to any one of claims 1 to 6, characterized in that: In the step S100, the expected shell temperature during the life assessment test of the high-power aerospace device is in a range. In the step S500, a constant voltage source is used to provide a stable power supply voltage for the heating resistor, and when the shell temperature of the high-power aerospace device exceeds the expected shell temperature range, the voltage of the constant voltage source is adjusted accordingly.

10. The shell temperature control method for a high power consumption aerospace device in a life assessment test according to any one of claims 1 to 6, characterized in that: The high-power consumption aerospace device is a DC / DC power supply, an LDO or an operational amplifier.

Images