A cryogenic refrigeration system with ultra-low disturbance and its control method

Abstract

A cryogenic refrigeration system and control method with ultra-low disturbance can reduce the impact of vibration on the workspace, reduce heat loss during transmission, and achieve cryogenic cooling of the controlled object to -150°C. o Below 100°C and under long-term precise control, this system avoids vibration interference caused by cryogenic liquid refrigeration, resulting in lower operating costs and high temperature control accuracy. The gas collection pipe is placed in liquid refrigerant. Power is supplied to the gas generator to vaporize the liquid refrigerant, producing cryogenic refrigeration gas, which is collected through the gas collection pipe. A cryogenic gas insulated transmission pipe introduces the refrigeration gas into the ultra-low temperature refrigeration working space. The object being refrigerated is placed in an ultra-high vacuum environment. Temperature control is achieved through heat exchange between the active temperature control layer and the object via thermal radiation. A temperature sensor measures the temperature of the active temperature control layer, and the control signal output by the temperature controller is fed back to the power supply of the cryogenic gas generator through the refrigeration logic control circuit, achieving high-precision ultra-low temperature control of the object.

Description

Technical Field

[0001] This invention relates to the technical field of cryogenic refrigeration, and more particularly to an ultra-low disturbance cryogenic refrigeration system and a control method for such an ultra-low disturbance cryogenic refrigeration system. Background Technology

[0002] Cryogenic refrigeration technology has a wide range of applications, such as cryopreservation of biological materials, blackbody radiation measurement, and low-temperature physics experiments. Many low-temperature processing technologies also require cryogenic refrigeration to ensure the precision and accuracy of the processing. Common materials used in cryogenic refrigeration include semiconductor refrigeration, physical refrigeration, and ultra-low temperature material refrigeration. For semiconductor refrigeration, it is usually used to cool the working object in the room temperature range, with the difference between the working temperature and the heat dissipation temperature being less than 30°C, thus its application is relatively limited. For physical refrigeration, common cooling methods include air cooling, water cooling, and oil cooling, which achieve cooling through heat dissipation and are also usually located in the room temperature range. For ultra-low temperature material refrigeration, the most common are liquid nitrogen and liquid helium. Due to their extremely low boiling point, they can achieve extremely low temperature control for the working material. In the chemical industry, liquid nitrogen (gas or liquid) is often used as a coolant. Its availability, low cost, and inert properties make it a convenient refrigerant. Its extremely low boiling point (-195.8°C) and high cooling capacity at atmospheric pressure make it a practical refrigerant in most low-temperature applications.

[0003] Common liquid nitrogen cryogenic refrigeration methods include: (1) direct surface cooling: liquid nitrogen cools the working material through a heat-conducting wall, and the heat exchange plate and the heat-conducting wall of the liquid nitrogen transmission pipe are in contact, using liquid nitrogen to remove the heat from the working material; (2) secondary loop cooling: by introducing an intermediate heat-conducting liquid, the liquid nitrogen heat-conducting wall is limited by the contact of the intermediate heat-conducting liquid, the intermediate heat-conducting liquid is cooled, and then the heat-conducting liquid is brought into contact with the heat-conducting wall of the working material to achieve refrigeration; (3) immersion cooling: the material is placed in liquid nitrogen for cooling; (4) spray cooling: liquid nitrogen is sprayed onto the surface of the material through a nozzle to achieve refrigeration; (5) cold nitrogen gas cooling: the liquid nitrogen is vaporized to obtain low-temperature nitrogen gas, which is used to cool the material. For some processes and experiments that are not sensitive to vibration, the above-mentioned liquid nitrogen refrigeration methods can meet the requirements well. However, for some experiments that are highly sensitive to vibration, such as optical experiments and ultra-low vibration cryogenic optical systems, the vibration and liquid nitrogen effects brought by these methods are difficult to guarantee the safety and stability of the system. Using liquid nitrogen for refrigeration can damage material structures, and the turbulent vibrations caused by liquid nitrogen flow can severely affect the stability of precision systems. Using nitrogen gas for refrigeration can reduce the impact of vibrations caused by fluid flow. However, when using cold nitrogen for refrigeration, the heat loss due to its high rate of heat transfer necessitates rigorous design and evaluation of the heat loss in each part of the system. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the technical problem to be solved by this invention is to provide an ultra-low disturbance cryogenic refrigeration system that can reduce the impact of vibration on the workspace, reduce heat loss during transmission, and achieve ultra-low temperature cooling of the controlled object to -150°C using ultra-low temperature gas. o It can be kept below 100°C and can be precisely controlled for a long time, avoiding vibration interference caused by low temperature liquid refrigeration, and has lower operating costs and high temperature control accuracy.

[0005] The technical solution of the present invention is: this ultra-low disturbance cryogenic refrigeration system includes: a cryogenic gas generator, a cryogenic gas transmission system, and a cryogenic working space;

[0006] The cryogenic gas generator includes a gas generator (1), a cryogenic liquid nitrogen storage system (2), a gas collection pipe (3), and a power supply (5). The cryogenic liquid nitrogen storage system contains liquid refrigerant. The gas collection pipe with a heat insulation layer (4) is placed in the liquid refrigerant. There is a certain distance between the gas collection pipe and the bottom of the cryogenic liquid nitrogen storage system. The gas generator is placed in the gas collection pipe. The power supply is used to power the gas generator so that the liquid refrigerant vaporizes to generate cryogenic cooling gas, which is then collected through the gas collection pipe.

[0007] The cryogenic gas transmission system includes three coaxial pipes: an outer shielding layer (6), a passive shielding layer (7), and a cryogenic gas transmission pipe (8). The cryogenic gas transmission pipe is directly connected to the gas collection pipe by welding to transmit the collected gas. The passive shielding layer is connected to the heat insulation layer and the vacuum working space (10). The passive shielding layer and the cryogenic gas transmission pipe are in a vacuum environment. The transmission loss is reduced by the vacuum environment. The outer shielding layer is connected to the exhaust gas collection pipe (12). The exhaust gas is used to cool the passive shielding layer and reduce its thermal radiation power.

[0008] The main body of the low-temperature working space is the vacuum working space (10). The heat exchange zone (14) for heat exchange of low-temperature refrigeration gas is located in the vacuum working space. The temperature of the heat exchange zone is measured by the temperature sensor (9), and the temperature data is transmitted to the temperature controller (16). The control signal output by the temperature controller is fed back to the power supply of the low-temperature gas generator through the refrigeration logic control circuit (15), thereby realizing the control of the low-temperature gas flow rate.

[0009] In this invention, a certain distance is maintained between the gas collection pipe and the bottom of the cryogenic liquid nitrogen storage system to ensure that the consumed refrigerant gas can be replenished in a timely manner. A gas generator is placed in the gas collection pipe; power is supplied to the gas generator to vaporize the liquid refrigerant, generating cryogenic refrigerant gas, which is then collected through the gas collection pipe. A cryogenic gas transmission pipe is directly welded to the gas collection pipe to transmit the collected gas. The passive shielding layer is connected to the thermal insulation layer and the vacuum working space. A vacuum environment exists between the passive shielding layer and the cryogenic gas transmission pipe to reduce transmission losses. The outer shielding layer is connected to the exhaust gas collection pipe, using the exhaust gas to cool the passive shielding layer and reduce its thermal radiation power. The cryogenic refrigerant gas undergoes heat exchange. The heat exchange zone is located within the vacuum working space. A temperature sensor measures the temperature of the heat exchange zone and transmits the data to a temperature controller. The control signal output by the temperature controller is fed back to the power supply of the cryogenic gas generator via a refrigeration logic control circuit, thereby controlling the cryogenic gas flow rate. Therefore, this invention achieves ultra-precise temperature control of the cryogenic working space by designing a cryogenic gas generator, a cryogenic gas transmission system, a heat exchange zone in the cryogenic working space, and an active temperature controller. Compared to commercial refrigeration systems, it reduces the impact of refrigeration structure vibration on the working space, reduces heat loss during transmission, and enables the use of cryogenic gas to cryogenically cool the controlled object to -150°C. o It can be kept below 100°C and can be precisely controlled for a long time, avoiding vibration interference caused by low temperature liquid refrigeration, and has lower operating costs and high temperature control accuracy.

[0010] A control method for an ultra-low disturbance cryogenic refrigeration system is also provided, which includes the following steps:

[0011] (1) In the vacuum working space, the temperature sensor acquires the temperature data signal of the object being controlled. The data signal is input to the temperature controller. At the same time, the temperature is acquired by the temperature acquisition card, and the data is recorded and plotted by the computer.

[0012] (2) The voltage signal output by the temperature controller is a DC signal. By filtering and amplitude compression of the voltage signal, the signal at this time is amplified by inverse addition with the signal from the voltage source that has been amplitude compressed, and then a voltage amplitude adjustment module is used to adjust the voltage amplitude.

[0013] (3) A voltage follower is used to isolate the front and back circuits. The signal output by the voltage follower and the controllable DC current source form a voltage-controlled constant current circuit to control the gas flow rate of the gas generator, thereby controlling the amount of low-temperature gas generated. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the ultra-low disturbance cryogenic refrigeration system according to the present invention.

[0015] Figure 2 This is a schematic diagram of the control circuit of the cryogenic refrigeration system with ultra-low disturbance according to the present invention.

[0016] Figure 3 This is a flowchart of a control method for an ultra-low disturbance cryogenic refrigeration system according to the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0018] It should be noted that the term "comprising" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products or devices.

[0019] like Figure 1 As shown, this ultra-low disturbance cryogenic refrigeration system includes: a cryogenic gas generator, a cryogenic gas transmission system, and a cryogenic working space;

[0020] The cryogenic gas generator includes a gas generator 1, a cryogenic liquid nitrogen storage system 2, a gas collection pipe 3, and a power supply 5. The cryogenic liquid nitrogen storage system contains liquid refrigerant. The gas collection pipe with a heat insulation layer 4 is placed in the liquid refrigerant. There is a certain distance between the gas collection pipe and the bottom of the cryogenic liquid nitrogen storage system. The gas generator is placed in the gas collection pipe. The power supply is used to power the gas generator to vaporize the liquid refrigerant and generate cryogenic cooling gas, which is collected through the gas collection pipe.

[0021] The cryogenic gas transmission system includes three coaxial pipes: an outer shielding layer 6, a passive shielding layer 7, and a cryogenic gas transmission pipe 8. The cryogenic gas transmission pipe is directly connected to the gas collection pipe by welding to transmit the collected gas. The passive shielding layer is connected to the heat insulation layer and the vacuum working space 10. The passive shielding layer and the cryogenic gas transmission pipe are in a vacuum environment, which reduces transmission loss. The outer shielding layer is connected to the exhaust gas collection pipe 12, which uses the exhaust gas to cool the passive shielding layer and reduce its thermal radiation power.

[0022] The low-temperature working space is placed flat on the working platform 11. The main body of the low-temperature working space is the vacuum working space 10. The heat exchange zone 14 for heat exchange of low-temperature refrigeration gas is located in the vacuum working space. The temperature of the heat exchange zone is measured by the temperature sensor 9 and the temperature data is transmitted to the temperature controller 16. The control signal output by the temperature controller is fed back to the power supply of the low-temperature gas generator through the refrigeration logic control circuit 15, thereby realizing the control of the low-temperature gas flow rate.

[0023] The other end of the exhaust gas collection pipe 12 is connected to the heat exchange zone 14, and the outer shielding layer is provided with a pipe to guide the exhaust gas into the exhaust gas collection tank 13.

[0024] In this invention, a certain distance is maintained between the gas collection pipe and the bottom of the cryogenic liquid nitrogen storage system to ensure that the consumed refrigerant gas can be replenished in a timely manner. A gas generator is placed in the gas collection pipe; power is supplied to the gas generator to vaporize the liquid refrigerant, generating cryogenic refrigerant gas, which is then collected through the gas collection pipe. A cryogenic gas transmission pipe is directly welded to the gas collection pipe to transmit the collected gas. The passive shielding layer is connected to the thermal insulation layer and the vacuum working space. A vacuum environment exists between the passive shielding layer and the cryogenic gas transmission pipe to reduce transmission losses. The outer shielding layer is connected to the exhaust gas collection pipe, using the exhaust gas to cool the passive shielding layer and reduce its thermal radiation power. The cryogenic refrigerant gas undergoes heat exchange... The heat exchange zone is located within the vacuum working space. Temperature sensors measure the temperature of the heat exchange zone and transmit the data to a temperature controller. The control signal output by the temperature controller is fed back to the power supply of the cryogenic gas generator via a refrigeration logic control circuit, thereby controlling the cryogenic gas flow rate. Therefore, this invention achieves ultra-precise temperature control of the cryogenic working space by designing a cryogenic gas generator, a cryogenic gas transmission system, a heat exchange zone in the cryogenic working space, and an active temperature controller. Compared to commercial refrigeration systems, it reduces the impact of refrigeration structure vibration on the working space, reduces heat loss during transmission, and enables the use of cryogenic gas to cryogenically cool the controlled object to -150°C. o It can be kept below 100°C and can be precisely controlled for a long time, avoiding vibration interference caused by low temperature liquid refrigeration, and has lower operating costs and high temperature control accuracy.

[0025] Preferably, the gas collecting pipe is made of copper, and the cryogenic liquid nitrogen storage system is sealed with a heat-insulating structure.

[0026] Preferably, the cryogenic gas transmission pipeline is made of stainless steel corrugated pipe.

[0027] Preferably, the cryogenic gas transmission system is connected to the pipeline in the cryogenic working space via a flange.

[0028] Preferably, all interfaces connected to the cryogenic working space use standard flanges, the cryogenic working space is located on an active vibration isolation platform, and the cryogenic working space is connected to the cryogenic gas transmission pipeline through a bellows.

[0029] Preferably, the temperature controller is a PID temperature servo controller. The output control voltage of the PID temperature servo controller is controlled by a refrigeration logic control circuit. The refrigeration logic control circuit amplifies, limits, and filters the signal before controlling the control power supply of the cryogenic gas generator, thereby changing the generation rate of the cryogenic gas.

[0030] like Figure 2 , 3 As shown, a control method for an ultra-low disturbance cryogenic refrigeration system is also provided, which includes the following steps:

[0031] (1) In the vacuum working space, the temperature sensor acquires the temperature data signal of the object being controlled. The data signal is input to the temperature controller. At the same time, the temperature is acquired by the temperature acquisition card, and the data is recorded and plotted by the computer.

[0032] (2) The voltage signal output by the temperature controller is a DC signal. By filtering and amplitude compression of the voltage signal, the signal at this time is amplified by inverse addition with the signal from the voltage source that has been amplitude compressed, and then a voltage amplitude adjustment module is used to adjust the voltage amplitude.

[0033] (3) A voltage follower is used to isolate the front and back circuits. The signal output by the voltage follower and the controllable DC current source form a voltage-controlled constant current circuit to control the gas flow rate of the gas generator, thereby controlling the amount of low-temperature gas generated.

[0034] Preferably, the control method further includes step (4), in which the theoretical simulation of the heat loss of the vacuum working space and the cryogenic gas transmission system is achieved through finite element simulation.

[0035] Preferably, the control method further includes step (5), in which the actual calculation of the heat loss of the vacuum working space and the cryogenic gas transmission system is carried out by multi-point temperature monitoring in the cryogenic gas transmission pipeline, and then the heat loss of the cryogenic gas is calculated.

[0036] The present invention will now be described in more detail.

[0037] 1. A cryogenic gas generator was constructed. The main body of the cryogenic gas generator is made of a cryogenic refrigerant storage system, and also includes a gas generator, a power supply, a gas collection pipeline, and a sealing system. The gas generator is used to vaporize the liquid refrigerant, and its current carrying capacity must meet the heat loss power consumption of the entire refrigeration system. The power supply needs to have an output power greater than the total heat loss power consumption of the entire refrigeration system to ensure that enough cryogenic gas can be generated to lower the temperature-controlled object from room temperature to the cryogenic cooling point. The gas collection pipeline is made of copper and collects the cryogenic gas into the cryogenic gas transmission system. The cryogenic liquid nitrogen storage structure adopts a sealed and insulated structure to ensure that the liquid level remains stable during the normal storage and collection of liquid refrigerant gas, reducing liquid nitrogen loss due to natural vaporization.

[0038] 2. A cryogenic gas transmission system was designed and manufactured. This system comprises a cryogenic gas transmission pipeline made of stainless steel corrugated pipe, an insulated transmission system for the pipeline, and a cryogenic environment shielding layer. The cryogenic gas transmission pipeline is connected to a cryogenic gas collection device. The passive shielding layer of the insulated transmission system is located outside the cryogenic gas transmission pipeline, forming a vacuum insulation layer between the shielding layer and the pipeline. This vacuum level reaches an ultra-high vacuum environment, reducing heat loss in the pipeline. The passive shielding layer ensures that the pipeline does not directly contact air, further reducing heat loss. An outer shielding layer is fitted over the passive shielding layer, with a cryogenic exhaust gas (temperature lower than air) between them. This exhaust gas is a cryogenic gas that has already undergone heat exchange within the working space. An active shielding layer ensures that the passive shielding layer remains in a cryogenic environment, reducing heat loss from thermal radiation. The cryogenic gas transmission system is connected to the pipeline in the working space via flanges to ensure airtightness. Since the transmission process involves the highest heat loss, even though a vacuum is used between the gas supply bellows and the outer bellows to eliminate heat loss from air conduction, heat loss from thermal radiation is still unavoidable. The magnitude of thermal radiation is related to the surface area difference between the outer gas supply pipe and the passive shielding layer, their respective temperatures, and the emissivity of the materials themselves. Therefore, the length and dimensions of the gas supply pipe and the passive shielding layer require strict design. The temperature of the gas supply pipe is consistent with the temperature of the cryogenic gas, and the temperature of the outer shielding layer is consistent with the air temperature. Therefore, a cryogenic environment is created through the outer shielding layer, ensuring that its temperature is lower than the ambient temperature, thus reducing thermal radiation from the gas supply pipe and the passive shielding layer. The constructed cryogenic environment is cooled by recovering the exhaust gas after heat exchange with the cryogenic gas through the working space.

[0039] 3. A high-vacuum, low-heat-loss cryogenic workspace was designed and fabricated. To cool the controlled object to below -150°C, the main heat loss comes from heat exchange between the controlled object and the external environment. Therefore, the controlled object is placed in a vacuum insulation system. The vacuum level affects the overall heat loss of the controlled object. Simultaneously, it is necessary to strictly control the temperature and flow rate of the cryogenic gas entering the active temperature control layer of the controlled object, as well as the vacuum level of the controlled object. The high-vacuum environment places extremely high demands on the interfaces of all parts; standard flange connections are used for all interfaces. To obtain a low-disturbance workspace and reduce the impact of vibration, the workspace is located on an active vibration isolation platform, and the workspace is connected to the cryogenic gas transmission pipeline via a corrugated pipe.

[0040] 4. An active servo control system for temperature was designed and fabricated. This system includes a temperature sensor, a PID temperature controller, a refrigeration logic control circuit, and a cryogenic gas generator. The temperature sensor is an ultra-low temperature sensor; the PID temperature controller is a commercially available temperature controller; and the refrigeration logic control circuit is a control circuit designed and fabricated based on an integrated operational amplifier. All control circuits are integrated onto a single 40mm*60mm PCB board. The control logic of the active servo control system is as follows: data obtained from the ultra-low temperature sensor is input to the PID temperature servo controller. The output control voltage of the PID temperature controller is controlled by the refrigeration logic control circuit. The refrigeration logic control circuit amplifies, limits, and filters the signal before controlling the power supply of the cryogenic gas generator, thereby changing the generation rate of the cryogenic gas.

[0041] 5. Theoretical simulations and practical calculations were performed on the heat loss of the vacuum working space and the cryogenic gas transfer system. An ultra-low disturbance cryogenic refrigeration working system was designed and fabricated. This ultra-low disturbance cryogenic working system is a concrete implementation of the ultra-low disturbance cryogenic refrigeration method. The theoretical simulation of the heat loss of the cryogenic working space and the cryogenic gas transfer system was achieved using finite element method (FEM). The practical calculation of the heat loss of the cryogenic working space and the cryogenic gas transfer system involved multi-point temperature monitoring within the cryogenic gas transfer pipeline to calculate the heat loss of the cryogenic gas. Through optimized design, the cryogenic gas transfer loss was ultimately reduced to less than 7W, and the vacuum working space heat loss was reduced to less than 5W.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An ultra-low-disturbance cryogenic refrigeration system, characterized by: It includes: Low-temperature gas generator, low-temperature gas transmission system, low-temperature working space; The low-temperature gas generator includes a gas generator (1), a low-temperature liquid nitrogen storage system (2), a gas collecting pipeline (3), and a power supply (5). The low-temperature liquid nitrogen storage system contains liquid refrigerant. The gas collecting pipeline with an adiabatic insulation layer (4) is placed in the liquid refrigerant. The gas collecting pipeline and the bottom of the low-temperature liquid nitrogen storage system are spaced apart by a certain distance. The gas generator is placed in the gas collecting pipeline. The power supply supplies power to the gas generator to make the liquid refrigerant vaporize to produce low-temperature refrigeration gas and collect the gas through the gas collecting pipeline. The low-temperature gas transmission system includes three coaxial pipelines, namely, an outer shielding layer (6), a passive shielding layer (7), and a low-temperature gas transmission pipeline (8). The low-temperature gas transmission pipeline is directly connected to the gas collecting pipeline through welding to transmit the collected gas. The passive shielding layer is connected to the adiabatic insulation layer and the vacuum working space (10). The passive shielding layer and the low-temperature gas transmission pipeline are in a vacuum environment to reduce transmission loss. The outer shielding layer is connected to the tail gas collecting pipeline (12) to use the tail gas to cool the passive shielding layer and reduce its thermal radiation power. The main body of the low-temperature working space is the vacuum working space (10). The heat exchange area (14) where the low-temperature refrigeration gas exchanges heat is arranged in the vacuum working space. A temperature sensor (9) is used to measure the temperature of the heat exchange area and transmit the temperature data to a temperature controller (16). The control signal output by the temperature controller is fed back to the power supply of the low-temperature gas generator through a refrigeration logic control circuit (15) to control the flow rate of the low-temperature gas.

2. The ultra-low disturbance cryogenic refrigeration system of claim 1, wherein: The gas collecting pipeline is made of copper, and the low-temperature liquid nitrogen storage system adopts a sealed insulation structure for sealing.

3. The ultra-low-disturbance cryogenic refrigeration system of claim 2, wherein: The low-temperature gas transmission pipeline is made of a stainless steel bellows.

4. The ultra-low-disturbance cryogenic refrigeration system of claim 3, wherein: The low-temperature gas transmission system and the pipeline in the low-temperature working space are connected through flanges.

5. The ultra-low-disturbance cryogenic refrigeration system of claim 4, wherein: The interfaces of each part connected to the low-temperature working space use standard flanges. The low-temperature working space is located on an active vibration isolation platform. The low-temperature working space and the low-temperature gas transmission pipeline are connected through a bellows.

6. The ultra-low-disturbance cryogenic refrigeration system of claim 5, wherein: The temperature controller is a PID temperature servo controller. The control voltage output by the PID temperature servo controller is controlled through a refrigeration logic control circuit. The refrigeration logic control circuit performs reverse amplification, amplitude limiting, and filtering on the signal to control the control power supply of the low-temperature gas generator, thereby changing the generation rate of the low-temperature gas.

7. The control method of an ultra-low-disturbance cryogenic refrigeration system of claim 1, characterized by: It includes the following steps: (1) The temperature sensor in the vacuum working space acquires the temperature data signal of the controlled temperature object. The data signal is input to the temperature controller. A temperature acquisition card is used to collect the temperature. The data is recorded and plotted by a computer. (2) The voltage signal output by the temperature controller is a direct current signal. The signal is filtered and amplitude-compressed. The signal is reverse-amplified by adding the signal from the amplitude-compressed voltage source. A voltage amplitude adjustment module is used to adjust the voltage amplitude. (3) The front-stage and rear-stage circuits are isolated by using a voltage follower, and a signal output by the voltage follower and a controllable direct current source form a voltage-controlled constant current circuit, so as to control the gas flow rate of the gas generator and further control the amount of the generated cryogenic gas.

8. The control method of an ultra-low-disturbance cryogenic refrigeration system according to claim 7, characterized in that: It further comprises step (4) that the theoretical simulation of the heat loss of the vacuum working space and the cryogenic gas transmission system is realized by means of finite element simulation.

9. The control method of an ultra-low-disturbance cryogenic refrigeration system according to claim 8, characterized in that: It further comprises step (5) that the actual calculation of the heat loss of the vacuum working space and the cryogenic gas transmission system is realized by means of multi-point temperature monitoring in the cryogenic gas transmission pipeline and further calculation of the heat loss of the cryogenic gas.

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