Active and passive temperature control combined mK-level ultra-stable constant temperature device and method

Abstract

The invention discloses an mK-level ultra-stable constant-temperature device and method combining active and passive temperature control, belongs to the technical field of aerospace, and aims to solve the problem that the constant-temperature stability of a constant-temperature system in the field of spacecrafts cannot reach the mK level. According to the scheme, an aluminum foil shell wraps the outer surface of a heat insulation structure, and a constant-temperature structure is arranged in a cube groove in the dead center of the heat insulation structure; the constant-temperature structure is a solid aluminum alloy cube block with a groove reserved in the middle, the outer surface of the constant-temperature structure is covered with a heating film, a temperature measurement I-path detection head of the high-precision thermodetector is arranged in the groove of the constant-temperature structure and used for detecting the real-time temperature of the constant-temperature structure, and a temperature measurement II-path detection head of the high-precision thermodetector is used for detecting the environment temperature. The real-time temperature and the environment temperature of the constant-temperature structure are simultaneously sent to the constant-temperature control circuit, and the constant-temperature structure calculates a corresponding voltage value to drive the heating film to carry out heating temperature control on the constant-temperature structure, so that the temperature of the constant-temperature structure reaches and is stabilized at the target temperature.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace technology, and in particular relates to a mK-level ultra-stable constant temperature device and method combining active and passive temperature control for precise constant temperature of a spacecraft. Background Art

[0002] High-precision spacecraft core temperature control is the prerequisite for achieving accurate and stable control of the spacecraft's internal temperature and thus ensuring the stability of the satellite's state and performance. Especially in the space gravitational wave detection mission, the high-precision laser interferometer measurement system and inertial measurement sensor have extremely high requirements for environmental stability, and temperature stability has an important impact on their performance. In order to ensure that the space gravitational wave satellite detector can detect gravitational wave signals with a frequency of 0.1mHz to 1Hz, the satellite optical platform temperature noise spectral density must be less than 0.1mK / Hz 1 / 2 , the temperature noise spectral density of the inertial sensor system needs to be less than 5μK / Hz 1 / 2 , which requires the constant temperature system to have a constant temperature stability of mK level.

[0003] Constant temperature technology includes passive constant temperature technology and active and passive combined constant temperature technology. Passive constant temperature technology mainly includes constant temperature technologies such as heat insulation, heat preservation, and heat dissipation. Its principle is to wrap and cover the required constant temperature structure with heat insulation materials or dissipate the internal heat through evaporation, conduction, radiation, etc., so as to achieve passive temperature control. At present, the widely used passive temperature control products include heat pipes, thermal control coatings, thermal conductive fillers, multi-layer insulation components, etc. Heat pipes spread heat through the evaporation and condensation of materials in the vacuum shell. In practical applications, heat pipes are usually used for heat dissipation and temperature control of large instruments with low accuracy. Thermal control coatings are coated with a coating with thermal radiation characteristics on the outer surface of the constant temperature structure. It is often used in passive constant temperature technology for satellite precision instruments, but the exhaust characteristics of the thermal control coating must be considered and a specific outlet path must be set. The design is relatively complex and is generally suitable for suppressing the influence of thermal radiation in the external environment. The multi-layer insulation component consists of a reflective screen with low thermal radiation emissivity and a thermal insulation structure with low thermal conductivity. Constant temperature is achieved by suppressing thermal radiation and heat conduction. Multilayer insulation components have the advantages of good thermal insulation performance, light weight, no pollution, low cost, and easy processing. Therefore, they are widely used in the constant temperature control of internal instruments in satellites and have become one of the most commonly used passive constant temperature means in spacecraft and other high and low temperature projects.

[0004] Passive thermostatic technology represented by multi-layer thermal insulation components is widely used in spacecraft, but pure passive thermostatic technology cannot achieve mK-level thermostatic stability. In order to meet the mK-level thermostatic stability requirements of space gravitational wave detection missions, it is necessary to adopt a thermostatic technology that combines active and passive technologies. The active and passive thermostatic technology is based on multi-layer thermal insulation components and can be divided into heating thermostatic control technology and cooling thermostatic control technology.

[0005] Refrigeration constant temperature control technology is a temperature control technology that uses semiconductor refrigerators or other refrigeration devices to lower the temperature to the set temperature. The patent "202410446919.7 A high-stability precision temperature control system for a microwave ground station" adopts a multi-stage temperature control solution of a liquid cooler and a TEC thermoelectric cooler to achieve a temperature control accuracy of 1°C. The refrigeration constant temperature control system will generate significant heat at the hot end during operation, and this heat must be quickly discharged from the system to avoid interfering with temperature regulation. To address this problem, the system is often equipped with a high-power cooling system. However, these cooling systems may cause significant noise interference to precision measuring equipment. Therefore, in applications that require extremely high precision, a refrigeration system may not be an ideal choice.

[0006] Heating constant temperature control technology refers to the temperature control technology that raises the temperature to the set temperature by heating film or other heating devices. Polyimide heating film has the advantages of high stability resistance, high electrical conductivity efficiency, excellent insulation performance, good film flexibility, low cost, etc. In addition, polyimide heating film can achieve high temperature control accuracy in heating control, and has strong applicability under different environments and requirements. In temperature control applications that pursue high stability, active heating control methods are widely used. The patent "202311368780.0 A small high-precision temperature control device" uses electric heating film and thermal control coating solutions to achieve temperature stability control of the controlled object better than 0.1K under the condition of large temperature fluctuations in the satellite (greater than 2°C); the patent "202111658327.4 A high-precision temperature control device for a space optical remote sensing satellite star sensor" uses electric heating film and multi-layer thermal insulation component solutions to achieve high-precision control of the temperature change range of the star sensor flange of 10±2°C. However, they cannot achieve the temperature stability requirements of the mK level and cannot be used in scenarios such as space gravitational wave detection that require high ambient temperature stability.

[0007] In summary, the thermostat device that combines the passive thermostat technology multi-layer insulation components and the active heating thermostat technology can meet the high stability of the onboard thermostat. However, the existing thermostat devices are not designed for spacecraft with high thermostat stability requirements, and the thermostat stability cannot reach the mK level; at the same time, the existing thermostat devices have poor adaptability to the use environment and are usually only applicable to a certain type of spacecraft. Therefore, it is necessary to design a mK-level thermostat device and method that combines active and passive technologies with high thermostat stability and strong environmental adaptability. Summary of the invention

[0008] In view of the problem that the thermostatic stability of the existing thermostatic systems in the field of spacecraft cannot reach the mK level, the present invention provides a mK-level ultra-stable thermostatic device and method combining active and passive temperature control.

[0009] In one aspect of the present invention, there is provided a mK-class ultra-stable constant temperature device combining active and passive temperature control, comprising a thermal structure, a high-precision thermometer 7, a constant temperature control circuit 8 and a heating film 5; the thermal structure comprises an aluminum foil shell 1, a heat insulation structure 2 and a constant temperature structure 3; the aluminum foil shell 1 is wrapped on the outer surface of the heat insulation structure 2, a cube groove is left in the center of the heat insulation structure 2, and the constant temperature structure 3 is placed in the cube groove in the center of the heat insulation structure 2; the constant temperature structure 3 is a solid aluminum alloy cube block with a groove in the middle, the outer surface of the constant temperature structure 3 is covered with a heating film 5, the temperature measurement I detection head of the high-precision thermometer 7 is set in the groove of the constant temperature structure 3, and is used to detect the real-time temperature of the constant temperature structure 3, and the temperature measurement II detection head of the high-precision thermometer 7 is used to detect the ambient temperature, the real-time temperature of the constant temperature structure 3 and the ambient temperature are sent to the constant temperature control circuit 8 at the same time, and the constant temperature structure 3 calculates the corresponding voltage value to drive the heating film 5 to heat the constant temperature structure 3 to achieve the temperature of the constant temperature structure 3 and stabilize at the target temperature.

[0010] Preferably, a host computer 9 is further included, and the constant temperature structure 3 sends the real-time temperature, target temperature, ambient temperature and voltage value for driving the heating film 5 of the constant temperature structure 3 to the host computer.

[0011] Preferably, the constant temperature control circuit 8 includes a digital-to-analog conversion circuit 8-1, a power amplifier circuit 8-2, a data processing circuit 8-3 and an isolation filter power supply circuit 8-4; the isolation filter power supply circuit 8-4 includes an analog power supply and a digital power supply; the analog power supply supplies power to the digital-to-analog conversion circuit 8-1 and the power amplifier circuit 8-2; the digital power supply supplies power to the data processing circuit 8-3;

[0012] The data processing circuit 8-3 receives the temperature data from the high-precision thermometer 7, calculates the digital output voltage value according to the temperature data, the digital-to-analog conversion circuit 8-1 converts the digital output voltage value into an analog output voltage value, and outputs the analog output voltage value to the power amplifier circuit 8-2. The voltage value output by the power amplifier circuit 8-2 after amplification is used to drive the heating film 5 to heat.

[0013] Preferably, the power amplifier circuit 8-2 includes a balancing resistor R2, an adjusting resistor R1, and an adjusting resistor R f and integrated operational amplifier A; the analog output voltage value is transmitted to the integrated operational amplifier A through the balancing resistor R2; the adjusting resistor R1 and the adjusting resistor R f Used to adjust the amplification factor A of the power amplifier circuit uf =1+R f / R1.

[0014] Preferably, the aluminum foil shell 1 is made of glass fiber cloth aluminum foil material, and the heat insulation structure 2 is made of polyurethane foam material with a thermal conductivity coefficient less than 0.024 W / (m·K) and a compression strength greater than 0.604 Mpa.

[0015] Preferably, the heating film 5 is a flexible polyimide heating film.

[0016] In a second aspect, the present invention provides a mK-level thermostatic method combining active and passive temperature control, which is implemented based on the mK-level ultra-stable thermostatic device combining active and passive temperature control, and comprises the following steps:

[0017] S1, set the target temperature T0, the constant temperature control circuit receives the real-time temperature T from the high-precision thermometer k and ambient temperature T W ; Where k represents the kth time data is received;

[0018] S2. The thermostat uses a discrete feedforward compensation adaptive incremental PID control algorithm for temperature control. The output voltage increment Δu(k) is calculated by the three most recent temperature deviations e(k-2), e(k-1), and e(k):

[0019] Δu(k)=(K pmn +K imn +K dmn )e(k)-(K pmn +2K dmn )e(k-1)+K dmn e(k-2)

[0020] e(k) is the kth temperature deviation, e(k) = T k -T0;

[0021] e(k-1) is the k-1th temperature deviation, e(k-1) = Tk-1-T0, T k-1 is the real-time temperature received for the k-1th time;

[0022] e(k-2) is the k-2th temperature deviation, e(k-2) = Tk-2-T0, T k-2 is the real-time temperature received for the k-2th time;

[0023] K pmn , K imn , K dmn They are proportional coefficient, integral coefficient, and differential coefficient respectively. m represents the initial temperature difference state, and n represents the external temperature fluctuation state. The proportional coefficient K corresponding to different m and n is pmn , integral coefficient K imn , differential coefficient K dmn Determined through thermal model simulation and PID parameter adjustment experiments;

[0024] S3. Get the digital output voltage value u(k):

[0025] u(k)=u(k-1)+Δu(k)

[0026] Where, u(k-1) is the k-1th digital output voltage value;

[0027] S4. The constant temperature control circuit 8 converts the digital output voltage value u(k) into an analog value and amplifies it to drive the heating film 5 for heating.

[0028] Preferably, the determination rule of the initial temperature difference state m is:

[0029] Calculate the ambient temperature T W The difference from the target temperature T0 is Δt1 = T W -T0, the initial temperature difference state m is determined by the temperature range of Δt1:

[0030] When 0k<Δt1≤1k, m=1,

[0031] When 1k<Δt1≤2k, m=2,

[0032] When 2k<Δt1, m=3;

[0033] The determination rule of the external temperature fluctuation state n is:

[0034] In the initial state, n=0, and the output voltage increment Δu(k) is calculated according to PID to obtain the voltage value for controlling the heating film until the constant temperature device reaches a stable state. The standard for reaching a stable state is that e(k) is less than 0.1mK for 100s continuously.

[0035] After the thermostat reaches a stable state, record the average ambient temperature within every p hundred seconds from the beginning of the stable state, and calculate the average temperature difference between two adjacent hundred seconds Δt2=t(p)-t(p-1), where t(p) and t(p-1) are the average ambient temperatures within the pth and p-1th hundred seconds, respectively. The external temperature fluctuation state n is determined by the temperature range of Δt2.

[0036] When -2.5k<Δt2≤-1.5k, n=1,

[0037] When -1.5k<Δt2≤-0.5k, n=2,

[0038] When -0.5k<Δt2≤0.5k, n=3,

[0039] When 0.5k<Δt2≤1.5k, n=4,

[0040] When 1.5k<Δt2, n=5;

[0041] Update the proportional coefficient K according to the new n value pmn , integral coefficient Kimn , differential coefficient K dmn , recalculate the output voltage increment Δu(k) and the digital output voltage value u(k) to achieve constant temperature.

[0042] According to a third aspect of the present invention, there is provided an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method according to claim 7 or 8 when executing the computer program.

[0043] According to a fourth aspect of the present invention, a computer-readable storage medium is provided for storing computer instructions, wherein the computer instructions implement the steps of the method according to claim 7 or 8 when executed by a processor.

[0044] Beneficial effects of the present invention:

[0045] 1. High constant temperature stability. The present invention designs a constant temperature device that combines a passive constant temperature technology multi-layer insulation component and an active heating constant temperature technology, and uses a feedforward compensation adaptive incremental PID constant temperature control algorithm. Before the temperature reaches a steady state, the optimal PID coefficient is adaptively determined using different initial temperature difference states m. After the temperature reaches a steady state, the optimal PID coefficient is updated using different external temperature fluctuation states n, so that the instructions for controlling the heating film are accurate, and finally the mK level constant temperature stability is achieved, which is much higher than the existing common k level constant temperature stability.

[0046] 2. Strong environmental adaptability. The multi-layer thermal insulation components and flexible heating films are easy to process and form, making the present invention applicable to spacecraft with different internal structures; feedforward compensation and adaptive algorithms make the thermostat applicable to different target temperatures and variable temperature environments; when the ambient temperature is lower than the temperature of the controlled object, and the temperature difference matches the heat consumption of the controlled object, the temperature control target can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of a mK-class ultra-stable constant temperature device combining active and passive temperature control according to the present invention;

[0048] Figure 2 It is a specific circuit schematic diagram of a mK-level ultra-stable constant temperature device combining active and passive temperature control according to the present invention;

[0049] Figure 3 It is a temperature curve diagram of a simulation experiment of an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0052] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0053] Specific implementation method 1: The following is combined Figures 1 to 3 The present embodiment is described. The present embodiment describes a mK-class ultra-stable constant temperature device combining active and passive temperature control, including a thermal structure, a high-precision temperature measuring instrument 7, a constant temperature control circuit 8 and a heating film 5; the thermal structure is used to reduce the interference of external temperature fluctuations on the constant temperature component, and the thermal structure includes an aluminum foil shell 1, a heat insulation structure 2 and a constant temperature structure 3; the aluminum foil shell 1 is wrapped on the outer surface of the heat insulation structure 2, a cube groove is left in the center of the heat insulation structure 2, and the constant temperature structure 3 is placed in the cube groove in the center of the heat insulation structure 2; the constant temperature structure 3 is a solid with a groove in the middle Aluminum alloy cube block, the outer surface of the constant temperature structure 3 is covered with a heating film 5, the temperature measuring I detection head of the high-precision thermometer 7 is set in the groove of the constant temperature structure 3, and is used to detect the real-time temperature of the constant temperature structure 3. The temperature measuring II detection head of the high-precision thermometer 7 is used to detect the ambient temperature. The real-time temperature of the constant temperature structure 3 and the ambient temperature are sent to the constant temperature control circuit 8 at the same time. The constant temperature structure 3 calculates the corresponding voltage value to drive the heating film 5 to heat the constant temperature structure 3 to control the temperature, so that the temperature of the constant temperature structure 3 reaches and stabilizes at the target temperature.

[0054] Furthermore, a host computer 9 is included, and the constant temperature structure 3 sends the real-time temperature, target temperature, ambient temperature and voltage value of driving the heating film 5 of the constant temperature structure 3 to the host computer.

[0055] The constant temperature control circuit 8 includes a digital-to-analog conversion circuit 8-1, a power amplifier circuit 8-2, a data processing circuit 8-3 and an isolation filter power supply circuit 8-4; the isolation filter power supply circuit 8-4 includes an analog power supply and a digital power supply; the analog power supply supplies power to the digital-to-analog conversion circuit 8-1 and the power amplifier circuit 8-2; the digital power supply supplies power to the data processing circuit 8-3;

[0056] The data processing circuit 8-3 receives the temperature data from the high-precision thermometer 7, calculates the digital output voltage value according to the temperature data, the digital-to-analog conversion circuit 8-1 converts the digital output voltage value into an analog output voltage value, and outputs the analog output voltage value to the power amplifier circuit 8-2. The voltage value output by the power amplifier circuit 8-2 after amplification is used to drive the heating film 5 to heat.

[0057] The data processing circuit 8-3 is a main control chip, and the output port of the main control chip is connected to the digital-to-analog conversion circuit 8-1; the main control chip receives the temperature measurement data of the high-precision thermometer 7, calculates the digital output voltage value using the temperature data, and transmits the temperature and output voltage value to the host computer 9 through the serial port.

[0058] The digital-to-analog conversion circuit 8 - 1 includes a digital-to-analog conversion chip DAC, which converts a digital output voltage value into an analog output voltage value, and outputs the analog output voltage value to the power amplifier circuit 8 - 2 .

[0059] The power amplifier circuit 8-2 includes a balancing resistor R2, an adjusting resistor R1, and an adjusting resistor R f and integrated operational amplifier A; the analog output voltage value is transmitted to the integrated operational amplifier A through the balancing resistor R2; the adjusting resistor R1 and the adjusting resistor R f Used to adjust the amplification factor A of the power amplifier circuit uf =1+R f / R1.

[0060] The aluminum foil shell 1 is made of glass fiber cloth aluminum foil material, and the heat insulation structure 2 is made of polyurethane foam material with a thermal conductivity coefficient less than 0.024 W / (m·K) and a compression strength greater than 0.604 Mpa.

[0061] The heating film 5 is a flexible polyimide heating film.

[0062] Specific implementation method 2: The following is combined Figures 1 to 3 This embodiment is described. This embodiment is a mK-level ultra-stable constant temperature method combining active and passive temperature control. This method is based on the mK-level ultra-stable constant temperature device combining active and passive temperature control described in the first embodiment. The method includes the following steps:

[0063] S1, set the target temperature T0, the constant temperature control circuit receives the real-time temperature T from the high-precision thermometer k and ambient temperature T W ; Where k represents the kth time data is received;

[0064] S2. The thermostat uses a discrete feedforward compensation adaptive incremental PID control algorithm for temperature control. The output voltage increment Δu(k) is calculated by the three most recent temperature deviations e(k-2), e(k-1), and e(k):

[0065] Δu(k)=(K pmn +K imn +K dmn )e(k)-(K pmn +2K dmn )e(k-1)+K dmn e(k-2)

[0066] e(k) is the kth temperature deviation, e(k) = T k -T0;

[0067] e(k-1) is the k-1th temperature deviation, e(k-1) = Tk-1-T0, T k-1 is the real-time temperature received for the k-1th time;

[0068] e(k-2) is the k-2th temperature deviation, e(k-2) = Tk-2-T0, T k-2 is the real-time temperature received for the k-2th time;

[0069] K pmn , K imn , K dmn They are proportional coefficient, integral coefficient, and differential coefficient respectively. m represents the initial temperature difference state, and n represents the external temperature fluctuation state. The proportional coefficient K corresponding to different m and n is pmn , integral coefficient K imn , differential coefficient K dmn Determined through thermal model simulation and PID parameter adjustment experiments;

[0070] S3. Get the digital output voltage value u(k):

[0071] u(k)=u(k-1)+Δu(k)

[0072] Where, u(k-1) is the k-1th digital output voltage value;

[0073] S4. The constant temperature control circuit 8 converts the digital output voltage value u(k) into an analog value and amplifies it to drive the heating film 5 for heating.

[0074] The determination rule of the initial temperature difference state m is:

[0075] Calculate the ambient temperature T W The difference from the target temperature T0 is Δt1 = T W -T0, the initial temperature difference state m is determined by the temperature range of Δt1:

[0076] When 0k<Δt1≤1k, m=1,

[0077] When 1k<Δt1≤2k, m=2,

[0078] When 2k<Δt1, m=3;

[0079] The determination rule of the external temperature fluctuation state n is:

[0080] In the initial state, n=0, and the output voltage increment Δu(k) is calculated according to PID to obtain the voltage value for controlling the heating film until the constant temperature device reaches a stable state. The standard for reaching a stable state is that e(k) is less than 0.1mK for 100s continuously.

[0081] After the thermostat reaches a stable state, record the average ambient temperature within every p hundred seconds from the beginning of the stable state, and calculate the average temperature difference between two adjacent hundred seconds Δt2=t(p)-t(p-1), where t(p) and t(p-1) are the average ambient temperatures within the pth and p-1th hundred seconds, respectively. The external temperature fluctuation state n is determined by the temperature range of Δt2.

[0082] When -2.5k<Δt2≤-1.5k, n=1,

[0083] When -1.5k<Δt2≤-0.5k, n=2,

[0084] When -0.5k<Δt2≤0.5k, n=3,

[0085] When 0.5k<Δt2≤1.5k, n=4,

[0086] When 1.5k<Δt2, n=5;

[0087] Update the proportional coefficient K according to the new n value pmn , integral coefficient K imn , differential coefficient K dmn , recalculate the output voltage increment Δu(k) and the digital output voltage value u(k) to achieve constant temperature.

[0088] For example, initially, n=0, m=1, K p10 , K i10 , K d10 is a known quantity, extracted from the experimental data set and substituted into Δu(k)=(K pmn +K imn +K dmn )e(k)-(K pmn +2K dmn )e(k-1)+K dmne(k-2) calculates the output voltage increment Δu(k), and then obtains the corresponding voltage value output.

[0089] After the thermostat reaches a stable state, the temperature range of Δt2 is determined to determine the external temperature fluctuation state n. If the value of n changes, for example, n = 4, the three coefficients K are updated. p14 , K i14 , K d14 Similarly, these three coefficients are also extracted from the experimental data set and re-substituted into the formula

[0090] Δu(k)=(K pmn +K imn +K dmn )e(k)-(K pmn +2K dmn )e(k-1)+K dmn e(k-2) is used to calculate the output voltage increment Δu(k), and then the corresponding voltage value is output. Finally, e(k) is less than 0.1mK within a time range of 10000s.

[0091] See also Figure 3 , the constant temperature device was simulated by simulation software, the ambient temperature was set to 25.99990℃, the random fluctuation of ambient temperature was 1℃ / s, and the ambient humidity was 40%, and the simulation temperature curve was obtained as follows Figure 3 It is concluded that the maximum temperature fluctuation can be less than 0.1 mK within 10000 s according to the embodiment of the present invention.

[0092] Specific implementation method three: An electronic device described in this implementation method includes a memory and a processor, the memory stores a computer program, and the processor implements the steps of the method described in implementation method two when executing the computer program.

[0093] Specific implementation method 4: This implementation method describes a computer-readable storage medium, which is used to store computer instructions. When the computer instructions are executed by a processor, the steps of the method described in implementation method 2 are implemented.

[0094] The memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory, ROM, a programmable read-only memory, PROM, an erasable programmable read-only memory, EPROM, an electrically erasable programmable read-only memory, EEPROM, or a flash memory. The volatile memory may be a random access memory, RAM, which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory static RAM, SRAM, dynamic random access memory dynamic RAM, DRAM, synchronous dynamic random access memory synchronous DRAM, SDRAM, double data rate synchronous dynamic random access memory double data rate SDRAM, DDRSDRAM, enhanced synchronous dynamic random access memory enhanced SDRAM, ESDRAM, synchronous link dynamic random access memory synch link DRAM, SLDRAM, and direct memory bus random access memory direct Rambus RAM, DRRAM. It should be noted that memory of the methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0095] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center through a wired such as coaxial cable, optical fiber, digital subscriber line digital subscriber line, DSL or wireless such as infrared, wireless, microwave, etc. to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium such as a floppy disk, a hard disk, a magnetic tape, an optical medium such as a high-density digital video disc (DVD), or a semiconductor medium such as a solid state disk (SSD).

[0096] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor for execution, or a combination of hardware and software modules in a processor for execution. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

[0097] It should be noted that the processor in the embodiment of the present application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiment can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, a digital signal processor DSP, an application-specific integrated circuit ASIC, a field programmable gate array FPGA or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined to perform. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0098] The above is a detailed introduction to the mK-level ultra-stable constant temperature device and method combining active and passive temperature control proposed in the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A mK-level ultra-stable constant temperature device combining active and passive temperature control, characterized in that: The invention comprises a thermal structure, a high-precision temperature measuring instrument (7), a constant temperature control circuit (8) and a heating film (5); the thermal structure comprises an aluminum foil shell (1), a heat insulation structure (2) and a constant temperature structure (3); the aluminum foil shell (1) is wrapped on the outer surface of the heat insulation structure (2), a cube groove is left in the center of the heat insulation structure (2), and the constant temperature structure (3) is placed in the cube groove in the center of the heat insulation structure (2); the constant temperature structure (3) is a solid aluminum alloy cube block with a groove in the middle, and the outer surface of the constant temperature structure (3) is covered with a heating film (5). The temperature measuring head of the high-precision thermometer (7) is arranged in the groove of the constant temperature structure (3) to detect the real-time temperature of the constant temperature structure (3). The temperature measuring head of the high-precision thermometer (7) is used to detect the ambient temperature. The real-time temperature of the constant temperature structure (3) and the ambient temperature are simultaneously sent to the constant temperature control circuit (8). The constant temperature structure (3) calculates the corresponding voltage value to drive the heating film (5) to heat the constant temperature structure (3) to control the temperature, so as to achieve the temperature of the constant temperature structure (3) reaching and stabilizing at the target temperature.

2. According to claim 1, a mK-level ultra-stable constant temperature device combining active and passive temperature control, characterized in that: It also includes a host computer (9), and the constant temperature structure (3) sends the real-time temperature of the constant temperature structure (3), the target temperature, the ambient temperature and the voltage value of the driving heating film (5) to the host computer.

3. The mK-level ultra-stable constant temperature device combining active and passive temperature control according to claim 1 or 2, characterized in that: The constant temperature control circuit (8) comprises a digital-to-analog conversion circuit (8-1), a power amplifier circuit (8-2), a data processing circuit (8-3) and an isolation filter power supply circuit (8-4); the isolation filter power supply circuit (8-4) comprises an analog power supply and a digital power supply; the analog power supply supplies power to the digital-to-analog conversion circuit (8-1) and the power amplifier circuit (8-2); the digital power supply supplies power to the data processing circuit (8-3); The data processing circuit (8-3) receives temperature data from a high-precision temperature measuring instrument (7), calculates a digital output voltage value based on the temperature data, and the digital-to-analog conversion circuit (8-1) converts the digital output voltage value into an analog output voltage value, and outputs the analog output voltage value to the power amplifier circuit (8-2). The voltage value outputted after amplification by the power amplifier circuit (8-2) is used to drive the heating film (5) to heat.

4. According to claim 3, a mK-level ultra-stable constant temperature device combining active and passive temperature control, characterized in that: The power amplifier circuit (8-2) includes a balancing resistor R2, an adjusting resistor R1, and an adjusting resistor R f and integrated operational amplifier A; the analog output voltage value is transmitted to the integrated operational amplifier A through the balancing resistor R2; the adjusting resistor R1 and the adjusting resistor R f Used to adjust the amplification factor A of the power amplifier circuit uf =1+R f / R1.

5. According to claim 1, a mK-level ultra-stable constant temperature device combining active and passive temperature control, characterized in that: The aluminum foil shell (1) is made of glass fiber cloth aluminum foil material, and the heat insulation structure (2) is made of polyurethane foam material with a heat conductivity coefficient of less than 0.024 W / (m·K) and a compression strength of greater than 0.604 Mpa.

6. According to claim 1, a mK-level ultra-stable constant temperature device combining active and passive temperature control, characterized in that: The heating film (5) is a flexible polyimide heating film.

7. A mK-level ultra-stable constant temperature method combining active and passive temperature control, the method is implemented based on the device described in any one of claims 1 to 6, characterized in that: The method comprises the following steps: S1, set the target temperature T0, the constant temperature control circuit receives the real-time temperature T from the high-precision thermometer k and ambient temperature T W ; Where k represents the kth time data is received; S2. The thermostat uses a discrete feedforward compensation adaptive incremental PID control algorithm for temperature control. The output voltage increment Δu(k) is calculated by the three most recent temperature deviations e(k-2), e(k-1), and e(k): Δu(k)=(K pmn +K imn +K dmn )e(k)-(K pmn +2K dmn )e(k-1)+K dmn e(k-2) e(k) is the kth temperature deviation, e(k) = T k -T0; e(k-1) is the k-1th temperature deviation, e(k-1) = Tk-1-T0, T k-1 is the real-time temperature received for the k-1th time; e(k-2) is the k-2th temperature deviation, e(k-2) = Tk-2-T0, T k-2 is the real-time temperature received for the k-2th time; K pmn , K imn , K dmn They are proportional coefficient, integral coefficient, and differential coefficient respectively. m represents the initial temperature difference state, and n represents the external temperature fluctuation state. The proportional coefficient K corresponding to different m and n is pmn , integral coefficient K imn , differential coefficient K dmn Determined through thermal model simulation and PID parameter adjustment experiments; S3. Get the digital output voltage value u(k): u(k)=u(k-1)+Δu(k) Where, u(k-1) is the k-1th digital output voltage value; S4, the constant temperature control circuit (8) converts the digital output voltage value u(k) into an analog value and amplifies it to drive the heating film (5) to heat.

8. The mK level ultra-stable constant temperature method combining active and passive temperature control according to claim 7 is characterized in that: The determination rule of the initial temperature difference state m is: Calculate the ambient temperature T W The difference from the target temperature T0 is Δt1 = T W -T0, the initial temperature difference state m is determined by the temperature range of Δt1: When 0k<Δt1≤1k, m=1, When 1k<Δt1≤2k, m=2, When 2k<Δt1, m=3; The determination rule of the external temperature fluctuation state n is: In the initial state, n=0, and the output voltage increment Δu(k) is calculated according to PID to obtain the voltage value for controlling the heating film until the constant temperature device reaches a stable state. The standard for reaching a stable state is that e(k) is less than 0.1mK for 100s continuously. After the thermostat reaches a stable state, record the average ambient temperature within every p hundred seconds from the beginning of the stable state, and calculate the average temperature difference between two adjacent hundred seconds Δt2=t(p)-t(p-1), where t(p) and t(p-1) are the average ambient temperatures within the pth and p-1th hundred seconds, respectively. The external temperature fluctuation state n is determined by the temperature range of Δt2. When -2.5k<Δt2≤-1.5k, n=1, When -1.5k<Δt2≤-0.5k, n=2, When -0.5k<Δt2≤0.5k, n=3, When 0.5k<Δt2≤1.5k, n=4, When 1.5k<Δt2, n=5; Update the proportional coefficient K according to the new n value pmn , integral coefficient K imn , differential coefficient K dmn , recalculate the output voltage increment Δu(k) and the digital output voltage value u(k) to achieve constant temperature.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method according to claim 7 or 8 when executing the computer program.

10. A computer-readable storage medium, characterized in that: Used to store computer instructions, which implement the steps of the method according to claim 7 or 8 when executed by a processor.

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