A bidirectional temperature control system for the gas chamber of an inertial measurement system based on a thermal atom ensemble

Abstract

The present invention provides an air chamber bidirectional temperature control system for an inertial measurement system based on a thermal atom ensemble. The system is characterized by comprising: a magnetic shielding tube, an air chamber, a cooling end heat conducting plate, a heating end heat conducting plate, a cooling end temperature measuring resistor, a heating end temperature measuring resistor, a heat sink, a first thermal switch, a second thermal switch, a third thermal switch, four sets of superconducting magnets, a magnetocaloric module ADR1 and a magnetocaloric module ADR2, a heating module, a control module, and a magnetic shielding layer. The system has an overall structure, a scientific and reasonable design, and safe and reliable operation. It avoids a passive cooling method that relies solely on natural heat dissipation and refrigeration. By combining passive heat dissipation with active control for cooling, the system has higher cooling efficiency, overcomes errors caused by long waiting times, and improves the temperature stability of the inertial measurement system based on the thermal atom ensemble. The system is suitable for popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature control system design, in particular to an air chamber bidirectional temperature control system of an inertial measurement system based on a thermal atom ensemble. Background Art

[0002] As an autonomous navigation system that does not require external information input, the inertial measurement system based on the hot atom ensemble has the advantages of high precision, fast response, and strong anti-interference ability. It plays a vital role in modern warfare and national defense and military construction. With the continuous development of informatization and intelligence in the quantum field, the hot atom ensemble inertial measurement system has good development prospects and huge development potential. In the future, it will become the backbone of the navigation market with advantages such as lower cost, higher precision and smaller size.

[0003] The hot atom ensemble inertial measurement system polarizes the alkali metal gas atoms in the gas chamber by applying a longitudinal static magnetic field and pump light to the gas chamber, thereby hyperpolarizing the nuclei in the gas chamber. Then, a transverse oscillating magnetic field is applied to cause the atomic nuclei in the gas chamber to resonate magnetically, generating a macroscopic magnetic moment. When the carrier rotates, the intensity of the received detection light will change. At this time, high-frequency carrier magnetic field modulation is used to filter out low-frequency noise, and then the horizontal magnetic field is obtained through demodulation, and finally the angular velocity of the carrier rotation is obtained.

[0004] The working principle shows that for an inertial measurement system based on a hot atom ensemble to function properly, the gas chamber must be heated to a high temperature to increase the number density of alkali metal atoms, maximizing the alkali metal vapor content within the chamber. This results in greater signal strength and an improved signal-to-noise ratio. However, when the temperature is too high, the collision rate between atoms increases, leading to increased broadening and hindering signal extraction. Therefore, there is an optimal operating temperature for a hot atom ensemble inertial measurement system with a fixed gas chamber composition.

[0005] At present, the research on gas and room temperature control is mainly divided into two parts:

[0006] On the one hand, there is research on current heating coils, which aims to improve heating efficiency and suppress the magnetic field generated during operation by changing the coil configuration and material.

[0007] On the other hand, there is research on high-precision temperature control circuits, which can improve the stability of heating by increasing control accuracy and response speed. However, when the ambient temperature rises, a single heating solution cannot quickly stabilize the temperature of the atomic gas chamber, and can only rely on natural cooling.

[0008] Therefore, bidirectional control of the gas chamber temperature is critical to improving the stability of the hot atom ensemble inertial measurement system. The current heating coils commonly used at present can only perform unidirectional heating and reduce the temperature by passive heat dissipation, but the ambient temperature fluctuates in both directions. When the ambient temperature rises, the heating temperature needs to be lowered. At this time, it can only wait for a period of time for it to cool naturally. There is a lack of active cooling control schemes suitable for inertial measurement systems based on hot atom ensembles. The temperature control efficiency is low and the temperature stability acting on alkali metal atoms is poor. Therefore, there is an urgent need for a temperature control system that can maintain temperature stability while being able to adjust the gas chamber temperature in both directions with a faster response.

[0009] In order to overcome the above technical defects, the existing technology proposes two solutions:

[0010] ① Bidirectional temperature control solution combining water cooling box and electric current heating technology;

[0011] The hot atom ensemble inertial measurement system is placed in a water cooling box to achieve cooling by lowering the temperature of the system's working environment;

[0012] However, water has a high specific heat capacity and low cooling efficiency, and the water-cooling box is large and difficult to miniaturize, which increases the system volume; the pumping vibration during the water-cooling box pumping process will generate a certain amount of noise, affecting the stability of the optical platform; the water-cooling box achieves the cooling effect by condensing the air in the box, which will cause a certain amount of water vapor in the box, which has a great impact on the optical path and causes errors; and the cost is high, and the requirements for the coolant are also high, and pure water needs to be prepared; the current water-cooling box integrates the condenser at the bottom, which will cause squeezing during transportation, resulting in damage to the condenser and high maintenance costs.

[0013] ② Thermoelectric cooler (TEC) control scheme;

[0014] The working principle of TEC cooling is thermoelectric conversion. When the TEC is connected to an external DC power supply, the electrons in the N-type semiconductor and the holes in the P-type semiconductor flow to one side due to the action of the electric field. This process will transfer heat. By changing the current passing through the TEC, the flow direction of electrons and holes in the semiconductor is changed, thereby changing the direction of heat absorption and heat release, achieving the effect of both heating and cooling.

[0015] However, TEC cooling efficiency is not high, and heating and cooling occur simultaneously. Auxiliary heat dissipation must be taken into account during cooling, otherwise the cooling effect will be affected. TEC devices will be damaged due to thermal fatigue during long-term thermal cycles, and they have no moving parts, so the maintenance cost is high.

[0016] ③ Stick a heating film on the outside of the oven and control the heating through electric current;

[0017] This heating method of electric heating film can provide faster temperature rise operation, and the heating temperature range is more balanced and controllable;

[0018] However, when the heating temperature needs to be lowered, the temperature can only be controlled through natural heat dissipation and PID, which will take a certain amount of time. In the process of waiting for heat dissipation to cool down, the internal or external environment of the air chamber may change. When the heat dissipation drops to a specific temperature, the temperature at this time may not necessarily be the temperature that maximizes the air chamber signal, which will introduce some unnecessary noise and reduce the signal-to-noise ratio. In addition, the accuracy of temperature control relying solely on heat dissipation is also limited. Summary of the Invention

[0019] In order to solve the above technical problems, the present invention provides a bidirectional temperature control system for the gas chamber of an inertial measurement system based on a hot atom ensemble. Based on adiabatic demagnetization and current heating technology, a bidirectional temperature control system for the gas chamber with both heating and cooling is designed. On one side, the magnetic entropy of the magnetocaloric module can be controlled by current, thereby controlling the temperature reduction; on the other side, the heating is turned off for natural heat dissipation while cooling is carried out, avoiding the inaccurate cooling method of relying solely on heat dissipation, improving the temperature control efficiency, and further improving the signal-to-noise ratio of the hot atom ensemble inertial measurement system.

[0020] A gas chamber bidirectional temperature control system for an inertial measurement system based on a thermal atom ensemble, comprising: a magnetic shielding cylinder, an gas chamber, a cooling end thermal conductive sheet, a heating end thermal conductive sheet, a cooling end temperature measuring resistor, a heating end temperature measuring resistor, a heat sink, a first thermal switch, a second thermal switch, a third thermal switch, four sets of superconducting magnets (a first superconducting magnet, a second superconducting magnet, a third superconducting magnet, and a fourth superconducting magnet), a magnetocaloric module ADR1 and a magnetocaloric module ADR2, a heating module, a control module, and a magnetic shielding layer;

[0021] As an example, the air chamber is the temperature control object of the present invention.

[0022] As an example, the temperature measuring resistor is a platinum resistor.

[0023] As an example, the heat sink uses a diamond heat sink, which has the characteristics of high thermal conductivity, low thermal expansion, and low thermal mismatch. The temperature of the diamond heat sink does not change with the heat transferred to it, and can help the heat source dissipate heat efficiently.

[0024] As an example, the three sets of thermal switches are used to control the transfer and blocking of heat. When the three sets of thermal switches are closed, heat is transferred, and when they are open, heat is insulated.

[0025] As an example, the four groups of superconducting magnets are sources of magnetic fields, the magnitude of which is controlled by electric current, and are used for the excitation and demagnetization operations of the magnetocaloric module ADR1 and the magnetocaloric module ADR2.

[0026] As an example, the magnetic thermal module ADR1 and the magnetic thermal module ADR2 are made of the magnetic thermal material potassium chromium sulfate dodecahydrate (CPA), and rely on its magnetocaloric effect to absorb and release heat;

[0027] The magnetic thermal module ADR1 and the magnetic thermal module ADR2 together constitute an ADR system.

[0028] As an example, the heating module is used to heat the heating end heat conducting plate.

[0029] As an example, the control module adopts a fuzzy neural network architecture to control the magnetic field changes of the four groups of superconducting magnets and control the on and off of the three groups of thermal switches, and has a PID control and adjustment function.

[0030] As an example, the magnetic shielding layer is used to reduce the impact of the magnetic fields of the four groups of superconducting magnets on the gas chamber.

[0031] A control method for a gas chamber bidirectional temperature control system of an inertial measurement system based on a thermal atom ensemble, comprising:

[0032] Step 1: When cooling is required;

[0033] ① The heating module is stopped, and one side of the heat conducting plate at the heating end is cooled passively by natural heat dissipation;

[0034] ② At the same time, close the third thermal switch, set the expected temperature, and actively cool down the cooling side by connecting the cooling end heat conducting plate of the ADR system;

[0035] ③ The active cooling process further includes: closing the first thermal switch and the second thermal switch, and the control module controlling the four sets of superconducting magnets to magnetize the magnetothermal module ADR1 and the magnetothermal module ADR2 to the corresponding maximum magnetic field, respectively, and entering the isothermal excitation stage;

[0036] ④ Then, the first thermal switch is disconnected, and the control module controls the first superconducting magnet and the second superconductor to perform adiabatic demagnetization. At this time, the temperature of the magnetocaloric module ADR1 decreases due to the decrease in magnetic field, increase in magnetic entropy, and decrease in thermal entropy. Since the second thermal switch is in a closed state, the magnetocaloric module ADR1 will simultaneously drive the magnetocaloric module ADR2 to cool down. When the temperature drops to near the expected temperature, the second thermal switch is disconnected;

[0037] As an example, the temperature near the expected temperature means a difference of 1-2°C from the expected temperature.

[0038] ⑤ Then, the control module controls the third superconducting magnet and the fourth superconductor to perform adiabatic demagnetization on the magnetocaloric module ADR2, so that the temperature of ADR2 is reduced to the expected temperature, and at the same time, the heat is transferred to the cooling end heat conducting plate through the heat bus to achieve cooling of the gas chamber.

[0039] As an example of the effect, the advantage of the cascade structure ADR system compared to the single-stage ADR is that it overcomes the single-stroke disadvantage of the single-stage ADR. After one refrigeration cycle is completed, there is no window period caused by the regeneration of a single ADR, and the cascade structure can achieve continuous refrigeration.

[0040] Step 2: When heating is required;

[0041] ① Simply disconnect the third thermal switch to cut off the cooling of the ADR system and use the control module to control heating;

[0042] ②At this time, the heating end heat conducting sheet electrically connected to the heating module will perform a precise and controllable heating operation on the air chamber.

[0043] Beneficial effects of the present invention:

[0044] The overall structure of the present invention is scientifically and rationally designed, and operates safely and reliably. It avoids the passive cooling method that relies solely on natural heat dissipation and refrigeration. By combining passive heat dissipation with active control for cooling, the cooling efficiency is higher, the error caused by long waiting times is overcome, and the temperature stability of the inertial measurement system based on the thermal atom ensemble is improved.

[0045] The present invention provides a bidirectional air chamber temperature regulation system that combines heating and cooling. The heating part uses current heating technology, and the cooling part adopts adiabatic demagnetization technology. While ensuring heating, it can cool down more efficiently. The invention has a fast cooling response, improves the air chamber temperature control accuracy, and helps to improve the signal-to-noise ratio of the thermal atom ensemble inertial measurement system.

[0046] The technical structure of the present invention using heating and cooling is superior to the structural design of the prior art, so that the floor area of ​​the entire volume is smaller than that of the prior design structure, and is suitable for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the overall structural design diagram of the gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble of the present invention.

[0048] Figure 2 This is a schematic diagram of the ADR structure of Example 2 of a gas chamber bidirectional temperature control system of an inertial measurement system based on a hot atom ensemble of the present invention.

[0049] Figure 3Schematic diagram of the ADR working principle of embodiment 2 of the gas chamber bidirectional temperature control system of the inertial measurement system based on the hot atom ensemble of the present invention DETAILED DESCRIPTION

[0050] Below, reference Figures 1 to 2 As shown, a gas chamber bidirectional temperature control system of an inertial measurement system based on a thermal atom ensemble comprises:

[0051] It includes: a magnetic shielding tube 1, an air chamber 2, a cooling end heat conducting sheet 3, a heating end heat conducting sheet 4, a cooling end temperature measuring resistor 5, and a heating end temperature measuring resistor 6.

[0052] The cooling end heat conducting sheet 3 and the heating end heat conducting sheet 4 are symmetrically arranged on the left and right sides of the air chamber 2 respectively; the cooling end temperature measuring resistor 5 is arranged on the right side of the cooling end heat conducting sheet 3; the heating end temperature measuring resistor 6 is arranged on the left side of the heating end heat conducting sheet 4;

[0053] The system further includes: a magnetic shielding layer 19 and a heat sink 7 in the magnetic shielding layer 19, a first thermal switch 8, a second thermal switch 9, a third thermal switch 10, a first superconducting magnet 11, a second superconducting magnet 12, a third superconducting magnet 13 and a fourth superconducting magnet 14, a magnetothermal module ADR115 and a magnetothermal module ADR216, a heating module 17, and a control module 18;

[0054] Wherein: one end of the heat sink 7 is connected to one end of the first thermal switch 8, the other end of the first thermal switch 8 is connected to one end of the magnetocaloric module ADR115, the other end of the magnetocaloric module ADR115 is connected to one end of the second thermal switch 9, the other end of the second thermal switch 9 is connected to one end of the magnetocaloric module ADR216, the other end of the magnetocaloric module ADR216 is connected to one end of the third thermal switch 10, and the other end of the third thermal switch 10 is connected to the lower end of the cooling end thermal conductive sheet 3; one end of the control module 18 is connected to one end of the first superconducting magnet 11; a second end of the control module 18 is connected to one end of the second superconducting magnet 12; a third end of the control module 18 is connected to one end of the third superconducting magnet 13; a fourth end of the control module 18 is connected to one end of the fourth superconducting magnet 14; a fifth end of the control module 18 is connected to one end of the heating module 17; the other end of the heating module 17 is connected to the lower end of the heating end thermal conductive sheet 4;

[0055] As an example, the air chamber 2 is the temperature control object of the present invention.

[0056] As an example, the cooling end temperature measuring resistor 5 and the heating end temperature measuring resistor 6 are both platinum resistors.

[0057] As an example, the heat sink 7 is a diamond heat sink, which has the characteristics of high thermal conductivity, low thermal expansion, and low thermal mismatch. The temperature of the diamond heat sink does not change with the heat transferred to it, and can help the heat source dissipate heat efficiently.

[0058] As an example, the first thermal switch 8, the second thermal switch 9, and the third thermal switch 10 are all used to control the transfer and blocking of heat. When the three sets of thermal switches are closed, heat is transferred, and when they are open, heat is insulated.

[0059] As an example, the four groups of superconducting magnets are the source of magnetic field, the magnitude of the magnetic field is controlled by current, and are used for the excitation and demagnetization operations of the magnetocaloric module ADR115 and the magnetocaloric module ADR216.

[0060] As an example, the magnetic thermal module ADR115 and the magnetic thermal module ADR216 are made of the magnetic thermal material potassium chromium sulfate dodecahydrate (CPA), and rely on its magnetocaloric effect to absorb and release heat;

[0061] The magnetic thermal module ADR115 and the magnetic thermal module ADR216 together constitute an ADR system.

[0062] As an example, the heating module 17 is used to heat the heating end heat conducting plate 4 .

[0063] As an example, the control module 18 adopts a fuzzy neural network architecture to control the magnetic field changes of the four groups of superconducting magnets and control the on and off of the three groups of thermal switches, and has a PID control and adjustment function.

[0064] As an example, the magnetic shielding layer 19 is used to reduce the influence of the magnetic fields of the four groups of superconducting magnets on the gas chamber.

[0065] A control method for a gas chamber bidirectional temperature control system of an inertial measurement system based on a thermal atom ensemble, comprising:

[0066] Step 1: When cooling is required;

[0067] ① The heating module 17 is stopped, and one side of the heating end heat conducting plate 4 is cooled passively by natural heat dissipation;

[0068] ② At the same time, close the third thermal switch 10, set the expected temperature, and actively cool down the cooling side by connecting the cooling end heat conducting plate 3 of the ADR system;

[0069] ③ The active cooling process further includes: closing the first thermal switch 8 and the second thermal switch 9, and the control module 118 controls the four sets of superconducting magnets to magnetize the magnetocaloric module ADR1 and the magnetocaloric module ADR2 to the corresponding maximum magnetic field, respectively, and enter the isothermal excitation stage;

[0070] ④ Then, the first thermal switch 8 is disconnected, and the control module 18 controls the first superconducting magnet 11 and the second superconductor 12 to perform adiabatic demagnetization. At this time, the temperature of the magnetocaloric module ADR1 decreases due to the decrease in magnetic field, increase in magnetic entropy, and decrease in thermal entropy. Since the second thermal switch 9 is in a closed state, the magnetocaloric module ADR1 will simultaneously drive the magnetocaloric module ADR2 to cool down. When the temperature drops to near the expected temperature, the thermal switch 9 is disconnected;

[0071] As an example, the temperature near the expected temperature means a difference of 1-2°C from the expected temperature.

[0072] ⑤ Then, the control module 18 controls the third superconducting magnet 13 and the fourth superconductor 14 to perform adiabatic demagnetization on the magnetocaloric module ADR2, so that the temperature of ADR2 is reduced to the expected temperature, and at the same time, the heat is transferred to the cooling end heat conducting plate 3 through the heat bus to realize the cooling operation of the gas chamber 2.

[0073] As an example of the effect, the advantage of the cascade structure ADR system compared to the single-stage ADR is that it overcomes the single-stroke disadvantage of the single-stage ADR. After one refrigeration cycle is completed, there is no window period caused by the regeneration of a single ADR, and the cascade structure can achieve continuous refrigeration.

[0074] Step 2: When heating is required;

[0075] ① Simply disconnect the third thermal switch 10 to cut off the cooling of the ADR system and use the control module 18 to control heating;

[0076] ② At this time, the heating end heat conducting plate 4 electrically connected to the heating module 17 will perform a precise and controllable heating operation on the air chamber 2.

[0077] In order to better illustrate the working principle of the present invention, the following examples are given through specific embodiments of key units:

[0078] Example 1:

[0079] The specific regeneration process of the cascade structure ADR system is as follows:

[0080] First, the first thermal switch 8 and the second thermal switch 9 are both in the off state, and the magnetocaloric module ADR1 is adiabatically excited by controlling the first superconducting magnet 11 and the second superconductor 12 until the regeneration temperature is reached;

[0081] Then, the first thermal switch 8 is turned on to put the magnetocaloric module ADR1 into an isothermal excitation state. When the magnetic field of the magnetocaloric module ADR1 reaches a maximum value, the first thermal switch 8 is turned off to perform adiabatic demagnetization on the magnetocaloric module ADR1 until the temperature of the magnetocaloric module ADR1 drops to an intermediate temperature.

[0082] Since the second thermal switch 9 is in the open state at this time, the magnetocaloric module ADR2 is adiabatically magnetized. When the temperature of the magnetocaloric module ADR2 rises to slightly above the intermediate temperature, the second thermal switch 9 is closed. At this time, the magnetocaloric module ADR1 is isothermally demagnetized and ADR2 is isothermally magnetized until the magnetocaloric module ADR2 reaches the corresponding maximum magnetic field.

[0083] Finally, the second thermal switch 9 is disconnected, and the magnetocaloric module ADR1 is adiabatically demagnetized to the maintenance temperature, which is slightly lower than the regeneration temperature of the magnetocaloric module ADR2. At the same time, the magnetocaloric module ADR2 is adiabatically demagnetized to the expected temperature, and the constant temperature cooling stage is entered again.

[0084] As an example, the adiabatic demagnetization method is an entropy change process based on the magnetocaloric effect, and its structural composition includes a magnetocaloric module, a superconducting magnet and a thermal switch; the magnetocaloric module is composed of magnetocaloric material and a thermal bus, and the magnetocaloric material relies on its magnetocaloric effect to absorb and release heat; the thermal bus is used to transfer heat, transferring heat to a heat sink or a cold head; the superconducting magnet is the source of the magnetic field, and the size of the magnetic field can be controlled by electric current; the thermal switch connects the heat sink and the magnetocaloric module to control whether it is adiabatic; the heat sink is a type of substance, and its temperature does not change with the heat energy transferred to it; the cold head is responsible for providing cooling to the load; the size of the magnetic field of the superconducting magnet is controlled by electric current, thereby causing the magnetocaloric module to absorb and release heat.

[0085] Example 2: Explanation of relevant knowledge;

[0086] Adiabatic demagnetization refrigeration is an entropy change process based on the magnetocaloric effect;

[0087] According to different types of magnets, it can be divided into paramagnetic salt adiabatic demagnetization and nuclear adiabatic demagnetization, and the cooling magnitudes of the two are mK and uK respectively.

[0088] From the perspective of entropy, entropy is a measure of the disorder of a system. Under adiabatic conditions, the entropy of the system becomes 0. For magnetocaloric materials, due to the orbital angular momentum and spin of the electrons in the atoms, the atoms have magnetic moments. When no external magnetic field is applied, the orientation of the magnetic moments is disordered. This disorder is the magnetic entropy S. B , which is the state with the largest magnetic entropy. In addition to magnetic entropy, temperature is also the main factor affecting the entropy change of magnetic medium, corresponding to the thermal entropy S of the system. T , so the entropy of the system is S = S T +S BWhen the magnetic medium is adiabatically magnetized, that is, an external magnetic field is applied, the directions of the magnetic moments tend to be arranged in the same direction and parallel to the external magnetic field, so the disorder decreases and the magnetic entropy decreases, △S B <0, because the entropy of the system changes to 0 during the adiabatic process, that is, △S=△S B +△S T =0, so there must be △S T >0, indicating that the degree of thermal motion of the molecules of the magnetocaloric material increases, heat is released to the outside, or in other words, under adiabatic conditions, the magnetic entropy is converted into lattice entropy, and the temperature rises; similarly, when adiabatic demagnetization is performed, the external magnetic field is removed, and the arrangement of each magnetic moment will return to the original chaotic state, the disorder increases, the magnetic entropy becomes larger, and △S B >0, so there must be △S T <0, which means absorbing heat from the outside, or lowering the temperature under adiabatic conditions to achieve a cooling effect.

[0089] For paramagnetic materials, their magnetization is reversible. When the material exchanges heat with the external environment, the intensity of the magnetic field can be controlled to make the material isothermal. Therefore, the cooling effect can be achieved by controlling the intensity of the external magnetic field and the heat exchange state.

[0090] The composition structure of ADR is as follows Figure 2 As shown in the figure, the three most basic components are the magnetocaloric module, superconducting magnet, and thermal switch. The magnetocaloric module consists of magnetocaloric material and a thermal bus. The magnetocaloric material absorbs and releases heat through its magnetocaloric effect. The thermal bus is used to transfer heat to a heat sink or cold head. The superconducting magnet is the source of the magnetic field, and the magnitude of the magnetic field can be controlled by current. The thermal switch connects the heat sink and the magnetocaloric module to control thermal insulation. The heat sink is a material whose temperature does not change with the amount of heat energy transferred to it. The cold head is responsible for providing cooling to the load.

[0091] The specific working process is as follows Figure 3 As shown, including:

[0092] (1) Adiabatic excitation of section ab. The thermal switch is disconnected and an external magnetic field is applied. Because it is an adiabatic condition, the magnetic entropy of the magnetocaloric module decreases and the thermal entropy increases, so the temperature rises to T h , that is, the heat sink temperature, reaches point b.

[0093] (2) Isothermal excitation in section bc. The thermal switch is closed, and the magnetocaloric module is connected to the heat sink. Then, a magnetic field is applied and the magnetization rate is controlled, so that the magnetocaloric module isothermally releases heat to the heat sink until the maximum magnetic field B is reached. h , arrive at point c.

[0094] (3) Adiabatic demagnetization in the cd section. The thermal switch is disconnected, reducing the magnetic field. At this time, the magnetic entropy increases and the thermal entropy decreases, so the system cools down to the cooling temperature T d , which is the target temperature of adiabatic demagnetization refrigeration;

[0095] (4) Isothermal demagnetization in the da stage. Control the demagnetization rate to make the magnetothermal module isothermal demagnetized until B d At this point, a refrigeration cycle is completed, in which the cooling process of the load is mainly carried out in the da section.

[0096] The above are only preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and core ideas of the present invention, and is not used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, etc. made within the ideas and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A bidirectional temperature control system for the gas chamber of an inertial measurement system based on a thermal atom ensemble. It is characterized by: include: A magnetic shielding tube and an air chamber, a cooling end heat conducting sheet, a heating end heat conducting sheet, a cooling end temperature measuring resistor, and a heating end temperature measuring resistor arranged in the magnetic shielding tube; Wherein: the cooling end heat conducting sheet and the heating end heat conducting sheet are symmetrically arranged on the left and right sides of the air chamber respectively; the cooling end temperature measuring resistor is arranged on the right side of the cooling end heat conducting sheet; the heating end temperature measuring resistor is arranged on the left side of the heating end heat conducting sheet; The system further comprises: a magnetic shielding layer and a heat sink in the magnetic shielding layer, a first thermal switch, a second thermal switch, a third thermal switch, a first superconducting magnet, a second superconducting magnet, a third superconducting magnet and a fourth superconducting magnet, a magnetothermal module ADR1 and a magnetothermal module ADR2, a heating module and a control module; Wherein: one end of the heat sink is connected to one end of the first thermal switch, the other end of the first thermal switch is connected to one end of the magnetocaloric module ADR1, the other end of the magnetocaloric module ADR1 is connected to one end of the second thermal switch, the other end of the second thermal switch is connected to one end of the magnetocaloric module ADR2, the other end of the magnetocaloric module ADR2 is connected to one end of the third thermal switch, and the other end of the third thermal switch is connected to the lower end of the cooling end thermal conductive sheet; one end of the control module is connected to one end of the first superconducting magnet; the second end of the control module is connected to one end of the second superconducting magnet; the third end of the control module is connected to one end of the third superconducting magnet; the fourth end of the control module is connected to one end of the fourth superconducting magnet; the fifth end of the control module is connected to one end of the heating module; and the other end of the heating module is connected to the lower end of the heating end thermal conductive sheet.

2. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 1, characterized in that: The gas chamber is the temperature control object of the present invention; the magnetic shielding layer is used to reduce the influence of the magnetic field of the four groups of superconducting magnets on the gas chamber.

3. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 1, characterized in that: The temperature measuring resistor at the cooling end and the temperature measuring resistor at the heating end are both platinum resistors.

4. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 1, characterized in that: The heat sink is made of a diamond heat sink, which has the characteristics of high thermal conductivity, low thermal expansion, and low thermal mismatch. The temperature of the diamond heat sink does not change with the heat transferred to it, and can help the heat source dissipate heat efficiently.

5. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 1, characterized in that: The first thermal switch, the second thermal switch and the third thermal switch are all used to control the transfer and blocking of heat. When the three sets of thermal switches are closed, heat is transferred, and when they are open, heat is insulated.

6. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 2, characterized in that: The four groups of superconducting magnets are sources of magnetic fields, the magnitude of which is controlled by electric current, and are used for the excitation and demagnetization operations of the magnetocaloric module ADR1 and the magnetocaloric module ADR2.

7. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 1, characterized in that: The magnetic thermal module ADR1 and the magnetic thermal module ADR2 are made of the magnetic thermal material potassium chromium sulfate dodecahydrate (CPA), and rely on its magnetocaloric effect to absorb and release heat; The magnetic thermal module ADR1 and the magnetic thermal module ADR2 together constitute an ADR system.

8. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 1, characterized in that: The heating module is used to heat the heating end heat conducting plate.

9. The gas chamber bidirectional temperature control system of the inertial measurement system based on the thermal atom ensemble according to claim 6, characterized in that: The control module adopts a fuzzy neural network architecture to control the magnetic field changes of the four groups of superconducting magnets and control the on and off of the three groups of thermal switches, and has a PID control and adjustment function.

10. A bidirectional temperature control system for an air chamber of an inertial measurement system based on a thermal atom ensemble according to any one of claims 1 to 9, characterized in that: Also included is a temperature control method, specifically: Step 1: When cooling is required; ① The heating module is stopped, and one side of the heat conducting plate at the heating end is cooled passively by natural heat dissipation; ② At the same time, close the third thermal switch, set the expected temperature, and actively cool one side of the cooling end heat conducting plate by connecting the cooling end heat conducting plate of the ADR system; ③ The active cooling process further includes: closing the first thermal switch and the second thermal switch, and the control module controlling the four sets of superconducting magnets to magnetize the magnetothermal module ADR1 and the magnetothermal module ADR2 to the corresponding maximum magnetic field, respectively, and entering the isothermal excitation stage; ④ Then, the first thermal switch is disconnected, and the control module controls the first superconducting magnet and the second superconductor to perform adiabatic demagnetization. At this time, the temperature of the magnetocaloric module ADR1 decreases due to the decrease in magnetic field, increase in magnetic entropy, and decrease in thermal entropy. Since the second thermal switch is in a closed state, the magnetocaloric module ADR1 will simultaneously drive the magnetocaloric module ADR2 to cool down. When the temperature drops to near the expected temperature, the second thermal switch is disconnected; ⑤ The control module controls the third superconducting magnet and the fourth superconductor to perform adiabatic demagnetization on the magnetocaloric module ADR2, so that the temperature of ADR2 is reduced to the expected temperature, and at the same time, the heat is transferred to the cooling end heat conducting plate through the heat bus to achieve cooling of the gas chamber; Step 2: When heating is required; ① Simply disconnect the third thermal switch to cut off the cooling of the ADR system and use the control module to control heating; ②At this time, the heating end heat conducting sheet electrically connected to the heating module will perform a precise and controllable heating operation on the air chamber.

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