An adaptive system and control method for starting a superconducting magnet cold head

Abstract

This invention discloses an adaptive system and control method for starting a superconducting magnet cold head, relating to the field of superconducting magnet technology. The adaptive system for starting a superconducting magnet cold head includes: a cold head, a frequency converter, and a control unit. The cold head is used to cool the superconducting coil and includes a drive motor that drives a piston inside the cold head to reciprocate for cooling. The frequency converter is electrically connected to the drive motor and is used to adjust the operating frequency of the drive motor. The control unit is signal-connected to the frequency converter and is configured to: when a restart is detected after the cold head has stopped, control the frequency converter to drive the drive motor to operate at a first frequency lower than a preset operating frequency; and when preset conditions are met, control the frequency converter to drive the drive motor back to the preset operating frequency. This configuration avoids the instantaneous heating shock that occurs inside the cold head when the superconducting magnet restarts after a cold head stop, which could cause a sharp rise in the temperature of the superconducting coil and lead to quench failure.

Description

Technical Field

[0001] This invention relates to the field of superconducting magnet technology, and in particular to an adaptive system and control method for starting a superconducting magnet cold head. Background Technology

[0002] Conductively cooled superconducting magnets utilize a cold head to provide a cryogenic environment for the superconducting coil through solid-state heat conduction. During steady-state operation, the superconducting magnet operates at full field. However, if the compressor stops for a period due to power outages, cooling water issues, or helium pressure problems, restarting the cold head can cause a brief thermal instability within the cold head during the startup process (for example, after turning off an air conditioner for a period in summer, restarting it results in the airflow being hot, close to room temperature, instead of comfortable cool air). In other words, although the cold head has started, it is heating instead of cooling, which significantly impacts the stability of the conductively cooled superconducting magnet and can lead to quench failure in severe cases. Existing conductively cooled superconducting magnets do not employ effective measures to suppress this instantaneous thermal shock during cold head shutdown and restart, failing to avoid the heating effect at startup and thus exposing the superconducting coil to a high risk of quench failure.

[0003] Therefore, how to prevent the instantaneous heating shock inside the cold head from causing a sharp rise in the temperature of the superconducting coil and leading to quench failure when the superconducting magnet restarts after a shutdown is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive system and control method for starting a superconducting magnet cold head, which can prevent the instantaneous heating shock inside the cold head from causing a sharp rise in the temperature of the superconducting coil and leading to quench loss when the superconducting magnet restarts after a cold head shutdown.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A superconducting magnet cold head start adaptive system includes: A cold head is used to cool a superconducting coil. The cold head includes a drive motor, which drives a piston inside the cold head to reciprocate in order to achieve cooling. A frequency converter is electrically connected to the drive motor and is used to adjust the operating frequency of the drive motor. The control unit is connected to the frequency converter signal and is configured to: when a restart is required after the cold head stops, control the frequency converter to drive the drive motor to run at a first frequency lower than the preset operating frequency, and when the preset conditions are met, control the frequency converter to drive the drive motor to return to the preset operating frequency.

[0006] In one possible implementation, it also includes a cryogenic holding container, which includes an inner cold shield and an outer container spaced apart, with a vacuum chamber formed between the inner cold shield and the outer container; The cryogenic container is equipped with current leads, which are electrically connected to a superconducting coil.

[0007] In one possible implementation, the cold head includes a primary cylinder and a secondary cylinder, with the diameter of the primary cylinder being larger than that of the secondary cylinder. A drive motor is located at the end of the primary cylinder away from the secondary cylinder. The primary cylinder passes through a cryogenic holding container, and the secondary cylinder is located inside the cryogenic holding container. A first connecting block is provided at the end of the secondary cylinder away from the primary cylinder, and a second connecting block is provided on the upper side of the superconducting coil. The first connecting block is connected to the second connecting block through a thermal connector to form a heat conduction circuit.

[0008] In one possible implementation, a first temperature sensor and a second temperature sensor are also included. The first temperature sensor is disposed on a first connecting block, and the second temperature sensor is disposed on a second connecting block. Both the first temperature sensor and the second temperature sensor are connected to the control unit via connectors.

[0009] In one possible implementation, a compressor is also included, which is connected to the cold head via a helium pipeline to provide high-pressure helium to the cold head.

[0010] In one possible implementation, a piston is provided inside the cold head, the piston including a primary piston and a secondary piston, a flange is provided between the primary cylinder and the drive motor, and the cold head is connected to the cryogenic holding container through the flange.

[0011] In one possible implementation, the preset operating frequency is 50Hz or 60Hz, the first frequency is 30Hz, and the preset conditions include the temperature detected by the first temperature sensor being lower than the temperature detected by the second temperature sensor.

[0012] This invention also provides an adaptive control method for starting a superconducting magnet cold head, applied to the aforementioned adaptive system for starting a superconducting magnet cold head. The method includes the following steps: Obtain the temperature T1 of the cold head near the end of the superconducting coil and the temperature T2 of the superconducting coil; When the cold head is detected to be in a stopped state and T1 is greater than T2, the operating frequency of the cold head will be reduced to a level lower than the preset operating frequency.

[0013] In one possible implementation, it also includes: When the cold block is detected to be in the start-up state and T1 is less than T2, the operating frequency of the cold block is restored to the preset operating frequency.

[0014] In one possible implementation, when the cold head is detected to be in a stopped state, and T1 is greater than T2, the operating frequency of the cold head is reduced to below a preset operating frequency, specifically including: The control unit receives the start command; The control unit sends a low-frequency signal to the frequency converter, controlling the drive motor to be in a low-speed reciprocating motion state at the moment of startup.

[0015] Compared with the above-mentioned background technology, the superconducting magnet cold head start adaptive system provided by the present invention has at least the following beneficial effects: This invention introduces a frequency converter between the drive motor and the control unit, allowing for precise adjustment of the drive motor's operating frequency. When the control unit detects a restart after a cold head shutdown, it first controls the frequency converter to drive the drive motor at a first frequency lower than the preset operating frequency. At this time, the piston's reciprocating speed decreases, reducing the violent disturbances caused by the high-temperature helium gas inside the piston. Furthermore, the superconducting magnet system has sufficient time to fill the piston with low-temperature helium gas, thus preventing the high-temperature helium gas from being rapidly transported to the cold end before sufficient heat exchange. Once the preset conditions are met—that is, the control unit detects that the cold end of the cold head has begun to enter normal cooling—the control unit then controls the frequency converter to restore the drive motor to the preset operating frequency, allowing the cold head to enter its rated cooling state. In summary, this invention effectively suppresses the instantaneous heating shock during the cold head restart process, preventing quench loss in the superconducting coil due to instantaneous temperature rise, and significantly improving the operational stability and reliability of the superconducting magnet under cold head shutdown-restart cycle conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the adaptive system structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the cold head structure provided in an embodiment of the present invention.

[0018] in: 110 - Cold head; 111 - First stage cylinder; 112 - Second stage cylinder; 113 - First stage piston; 114 - Second stage piston; 115 - Flange; 120 - Drive motor; 130 - Frequency converter; 131 - Cable; 140 - Control Unit; 151 - Inner cold shield; 152 - Outer container; 160-Current Lead; 170-Superconducting coil; 181 - First connecting block; 182 - Second connecting block; 183 - Thermal connector; 191 - First temperature sensor; 192 - Second temperature sensor; 193 - Connector; 194 - First lead; 195 - Second lead; 200 - Compressor; 210 - Helium pipeline. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0020] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left" and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the position or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of this invention.

[0022] The purpose of this invention is to provide an adaptive system and control method for starting a superconducting magnet cold head, which can prevent the instantaneous heating shock inside the cold head from causing a sharp rise in the temperature of the superconducting coil and leading to quench loss when the superconducting magnet restarts after a cold head shutdown.

[0023] To achieve the above objectives, the present invention provides the following technical solution: Please see Figure 1 and Figure 2 This embodiment provides a superconducting magnet cold head start-up adaptive system, including a cold head 110, a frequency converter 130, and a control unit 140.

[0024] The cold head 110 is used to cool the superconducting coil 170. The cold head 110 includes a drive motor 120, which drives the piston inside the cold head 110 to reciprocate to achieve cooling. Specifically, the drive motor 120 is connected to the piston inside the cold head 110 through a crank-connecting rod mechanism or a similar mechanical transmission structure. One rotation of the motor drives the piston to complete one reciprocating motion, thereby driving the working fluid helium gas to complete the compression and expansion cycle inside the cold head 110, thus generating a cooling effect at the cold end.

[0025] The frequency converter 130 is electrically connected to the drive motor 120 via cable 131. The frequency converter 130 is used to adjust the operating frequency of the drive motor 120. The frequency converter 130 can output AC power of different frequencies to the drive motor 120, thereby adjusting the speed of the drive motor 120 and thus adjusting the frequency of the piston reciprocating motion.

[0026] Control unit 140 is signal-connected to frequency converter 130. Control unit 140 is configured to: when a restart is required after the cold head 110 has stopped, control frequency converter 130 to drive drive motor 120 at a first frequency lower than the preset operating frequency; and when preset conditions are met, control frequency converter 130 to drive drive motor 120 back to the preset operating frequency. Control unit 140 can be implemented using programmable controllers such as PLCs, microcontrollers, or industrial control computers. It should be noted that the preset operating frequency here is the normal operating frequency of drive motor 120.

[0027] This invention introduces a frequency converter 130 between the drive motor 120 and the control unit 140, allowing the operating frequency of the drive motor 120 to be precisely adjusted. When the control unit 140 detects that the cold head 110 has stopped and is restarting, it first controls the frequency converter 130 to drive the drive motor 120 at a first frequency lower than the preset operating frequency. At this time, the reciprocating speed of the piston is reduced, which can reduce the violent disturbance caused by the high-temperature helium gas inside the piston. Moreover, the superconducting magnet system has sufficient time to fill the piston with low-temperature helium gas. In this way, the high-temperature helium gas at the hot end is prevented from being rapidly transported to the cold end before sufficient heat exchange. When the preset condition is met, that is, when the control unit 140 detects that the cold end of the cold head 110 has begun to enter the normal cooling state, the control unit 140 then controls the frequency converter 130 to restore the drive motor 120 to the preset operating frequency, so that the cold head 110 enters the rated cooling state. In summary, the present invention can effectively suppress the instantaneous heating shock during the restart process of the cold head 110 after shutdown, avoid the superconducting coil 170 from losing quench due to instantaneous temperature rise, and significantly improve the operational stability and reliability of the superconducting magnet under the shutdown-restart cycle of the cold head 110.

[0028] In one possible implementation, the adaptive system further includes a cryogenic holding container, which includes an inner cold shield 151 and an outer container 152 spaced apart, forming a vacuum chamber between the inner cold shield 151 and the outer container 152; the cryogenic holding container is also provided with a current lead 160, which is electrically connected to a superconducting coil 170.

[0029] In this embodiment, the vacuum chamber formed between the inner cold shield 151 and the outer container 152 effectively blocks convection and gas heat conduction between the external environment and the superconducting coil 170, leaving only radiative heat transfer and a limited solid heat conduction channel. This minimizes the impact of the external environment on the low-temperature environment, and, together with the conductive cooling of the cold head 110, maintains a stable low-temperature environment for the superconducting coil 170. The current lead 160 allows the excitation current to be safely introduced from the ambient temperature outside into the low-temperature superconducting coil 170. More specifically, in this embodiment, the inner cold shield is a 50K cold shield, the outer container is a 300K container, and the current lead is connected to the superconducting coil via an internal cable.

[0030] In one possible implementation, the cold head 110 includes a primary cylinder 111 and a secondary cylinder 112, with the diameter of the primary cylinder 111 being larger than that of the secondary cylinder 112. A drive motor 120 is disposed at the end of the primary cylinder 111 away from the secondary cylinder 112. The primary cylinder 111 passes through a cryogenic holding container, and the secondary cylinder 112 is located inside the cryogenic holding container. A first connecting block 181 is disposed at the end of the secondary cylinder 112 away from the primary cylinder 111. A second connecting block 182 is disposed on the upper side of the superconducting coil 170. The first connecting block 181 is connected to the second connecting block 182 through a thermal connector 183 to form a heat conduction circuit.

[0031] Specifically, such as Figure 2 As shown, the cold head 110 in this embodiment adopts a two-stage structure of a first-stage cylinder 111 and a second-stage cylinder 112, enabling the cold head 110 to achieve two-stage cooling in sequence. The first-stage cold end obtains an intermediate temperature, and the second-stage cold end obtains a lower temperature, meeting the requirements of the superconducting coil 170 for an extremely low temperature environment. The second-stage cylinder 112 is located inside the cryogenic holding container and is connected to the superconducting coil 170 through a heat conduction circuit formed by the first connecting block 181, the thermal connector 183, and the second connecting block 182, ensuring that the cooling energy can be conducted to the superconducting coil 170 with the shortest path and the lowest thermal resistance, thereby improving cooling efficiency. At the same time, if the cold head 110 exhibits a heating effect at the moment of startup, the heat will also directly impact the superconducting coil 170 through this heat conduction circuit. This is precisely the conduction path of the instantaneous thermal shock problem that this invention needs to solve. Therefore, the monitoring and feedback control of the temperature along this path in this invention is of targeted significance.

[0032] In one possible implementation, a first temperature sensor 191 and a second temperature sensor 192 are also included. The first temperature sensor 191 is disposed on the first connecting block 181, and the second temperature sensor 192 is disposed on the second connecting block 182. Both the first temperature sensor 191 and the second temperature sensor 192 are connected to the control unit 140 through a connector 193.

[0033] Specifically, such as Figure 1 As shown, in this embodiment, a first temperature sensor 191 and a second temperature sensor 192 are respectively set on the first connecting block 181 (i.e., the cold end side of the cold head 110) and the second connecting block 182 (i.e., the superconducting coil 170 side). The two temperature sensors are respectively connected to the connector 193 through the first lead 194 and the second lead 195. The connector 193 is directly connected to the control unit 140. The first temperature sensor 191 and the second temperature sensor 192 are used to monitor the cold end temperature T1 of the cold head 110 and the temperature T2 of the superconducting coil 170 in real time, and transmit the temperature signals to the control unit 140 through the connector 193. The control unit 140 can accurately determine whether the cold head 110 is in a cooling state or a heating state based on the relative relationship between the two temperatures. Specifically, when T1 is lower than T2, the cold head 110 absorbs heat and cools normally. When T1 is higher than T2, the cold head 110 releases heat in the opposite direction to heat the superconducting coil 170, thereby providing an accurate basis for subsequent adaptive control based on temperature feedback.

[0034] In one possible implementation, a compressor 200 is also included, which is connected to the cold head 110 via a helium line 210 to provide high-pressure helium to the cold head 110.

[0035] In this embodiment, the compressor 200 forms a closed helium circulation loop with the cold head 110 through the helium pipeline 210, providing a continuous and stable high-pressure, low-temperature helium to the inside of the cold head 110, which is the working fluid source for the cold head 110 to achieve refrigeration. When the compressor 200 restarts after stopping due to power, cooling water, or helium pressure issues, the helium circulation has just resumed, and a stable low-temperature state has not yet been formed inside the cold head 110. This is a typical operating condition where the instantaneous thermal shock that this invention aims to avoid occurs.

[0036] In one possible implementation, a piston is provided inside the cold head 110, the piston including a primary piston 113 and a secondary piston 114, a flange 115 is provided between the primary cylinder 111 and the drive motor 120, and the cold head 110 is connected to the cryogenic container through the flange 115.

[0037] Specifically, such as Figure 2As shown, the first-stage piston 113 and the second-stage piston 114 reciprocate within the first-stage cylinder 111 and the second-stage cylinder 112, respectively, to achieve synchronous propulsion of the two-stage gas circulation, enabling the cold head 110 to obtain staged cooling capability; the flange 115 provides a detachable connection interface between the cold head 110 and the cryogenic holding container, facilitating the installation, maintenance and replacement of the cold head 110, and also serves as a seal to prevent the vacuum level of the vacuum chamber inside the cryogenic holding container from decreasing.

[0038] In one possible implementation, the preset operating frequency is 50Hz or 60Hz, the first frequency is 30Hz, and the preset conditions include that the temperature detected by the first temperature sensor 191 is lower than the temperature detected by the second temperature sensor 192.

[0039] Understandably, the operating frequency and the first frequency can be adjusted appropriately according to the actual application scenario. This article does not make specific restrictions here. However, it should be noted that the first frequency should be less than the preset operating frequency. Preferably, the first frequency is about half or even lower than the preset operating frequency. In this way, the piston reciprocating speed is significantly reduced, and the superconducting magnet system has enough time to establish a low temperature environment, thereby avoiding instantaneous heating shock.

[0040] Furthermore, in this embodiment, the temperature detected by the first temperature sensor 191 is lower than the temperature detected by the second temperature sensor 192 as a preset condition, that is, the temperature of the cold end of the cold head is lower than the temperature of the superconducting coil. At this time, the cold head 110 has established a normal cooling state, and switching back to the preset operating frequency will no longer cause thermal shock to the superconducting coil 170.

[0041] This invention also provides an adaptive control method for starting a superconducting magnet cold head, applied to the aforementioned adaptive system for starting a superconducting magnet cold head. The method includes the following steps: The temperature T1 of the cold head 110 near the end of the superconducting coil 170 and the temperature T2 of the superconducting coil 170 are obtained. When the cold head 110 is detected to be in a stopped state and T1 is greater than T2, the operating frequency of the cold head 110 is reduced to a level lower than the preset operating frequency.

[0042] By monitoring the working status of the cold head 110 and the temperature of the cold end of the cold head 110 and both sides of the superconducting coil 170 in real time, the system automatically identifies the working conditions where restarting is required after shutdown and there is a risk of heating, i.e., T1>T2. It then actively reduces the working frequency to a level lower than the preset working frequency, which is the preset working frequency of the cold head 110. In this way, the cold head 110 will run at a lower working frequency when restarting, thereby suppressing the heating shock at the moment of startup without manual intervention. It has strong adaptability and high reliability, and can effectively prevent the superconducting coil 170 from losing its supercharger due to instantaneous temperature rise.

[0043] In a possible implementation, the superconducting magnet cold head startup adaptive control method further includes: When it is detected that the cold head 110 is in the startup state and T1 is less than T2, the operating frequency of the cold head 110 is restored to the preset operating frequency.

[0044] When T1 < T2, that is, when the cold head 110 has successfully established a refrigeration state and the cold end temperature is lower than the temperature of the superconducting coil 170, switching back to the preset operating frequency at this time can enable the cold head 110 to quickly enter the rated refrigeration mode, timely provide sufficient cooling capacity for the superconducting coil 170, avoid the problem of insufficient refrigeration efficiency caused by long-term low-frequency operation, and achieve a smooth transition from low-frequency startup to steady-state high-frequency operation.

[0045] In a possible implementation, when it is detected that the cold head 110 is in the shutdown state and T1 is greater than T2, the operating frequency of the cold head 110 is lowered below the preset operating frequency, specifically including: The control unit 140 receives a startup instruction; The control unit 140 sends a low-frequency signal to the frequency converter 130 to control the drive motor 120 to be in a low-speed reciprocating motion state at the moment of startup.

[0046] With this setting, the execution process of the control unit 140 immediately sending a low-frequency signal to the frequency converter 130 after receiving the startup instruction is clarified, enabling the drive motor 120 to enter the low-speed reciprocating motion state at the moment of startup, rather than starting at the preset operating frequency, that is, the normal operating frequency and then reducing the frequency. This fundamentally avoids the heating impact caused by high-speed reciprocation at the moment of startup; at the same time, this control process has clear logic and is easy to implement in controller devices such as PLCs or single-chip microcontrollers.

[0047] It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0048] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0049] The above has introduced the embodiments provided by the present invention in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A superconducting magnet cold head start adaptive system, characterized in that, include: A cold head (110) is used to cool a superconducting coil (170). The cold head (110) includes a drive motor (120) for driving a piston inside the cold head (110) to reciprocate in order to achieve cooling. A frequency converter (130) is electrically connected to the drive motor (120) and is used to adjust the operating frequency of the drive motor (120); The control unit (140) is connected to the frequency converter (130) by signal. The control unit (140) is configured to: when it is detected that the cold head (110) needs to be restarted after it stops, control the frequency converter (130) to drive the drive motor (120) to run at a first frequency lower than the preset operating frequency, and when the preset conditions are met, control the frequency converter (130) to drive the drive motor (120) to return to the preset operating frequency.

2. The superconducting magnet cold head start-up adaptive system according to claim 1, characterized in that, It also includes a cryogenic holding container, which includes an inner cold shield (151) and an outer container (152) spaced apart, with a vacuum chamber formed between the inner cold shield (151) and the outer container (152); The cryogenic container is provided with a current lead (160), which is electrically connected to the superconducting coil (170).

3. The superconducting magnet cold head start adaptive system according to claim 2, characterized in that, The cold head (110) includes a primary cylinder (111) and a secondary cylinder (112), and the diameter of the primary cylinder (111) is larger than that of the secondary cylinder (112). The drive motor (120) is located at the end of the primary cylinder (111) away from the secondary cylinder (112). The primary cylinder (111) passes through the cryogenic holding container and the secondary cylinder (112) is located inside the cryogenic holding container. A first connecting block (181) is provided at the end of the secondary cylinder (112) away from the primary cylinder (111). A second connecting block (182) is provided on the upper side of the superconducting coil (170). The first connecting block (181) is connected to the second connecting block (182) through a thermal connector (183) to form a heat conduction circuit.

4. The superconducting magnet cold head start adaptive system according to claim 3, characterized in that, It also includes a first temperature sensor (191) and a second temperature sensor (192). The first temperature sensor (191) is disposed on the first connecting block (181), and the second temperature sensor (192) is disposed on the second connecting block (182). Both the first temperature sensor (191) and the second temperature sensor (192) are connected to the control unit (140) through a connector (193).

5. The superconducting magnet cold head start-up adaptive system according to claim 1, characterized in that, It also includes a compressor (200) which is connected to the cold head (110) via a helium pipeline (210) to provide high-pressure helium to the cold head (110).

6. The superconducting magnet cold head start-up adaptive system according to claim 3, characterized in that, A piston is provided inside the cold head (110), the piston includes a primary piston (113) and a secondary piston (114), a flange (115) is provided between the primary cylinder (111) and the drive motor (120), and the cold head (110) is connected to the cryogenic container through the flange (115).

7. The superconducting magnet cold head start adaptive system according to claim 4, characterized in that, The preset operating frequency is 50Hz or 60Hz, the first frequency is 30Hz, and the preset conditions include that the temperature detected by the first temperature sensor (191) is lower than the temperature detected by the second temperature sensor (192).

8. A control method for an adaptive system for starting a superconducting magnet cold head, characterized in that, The method, applied to the superconducting magnet cold head start adaptive system as described in any one of claims 1-7, comprises the following steps: The temperature T1 of the cold head (110) near the end of the superconducting coil (170) and the temperature T2 of the superconducting coil (170) are obtained; When the cold head (110) is detected to be in a shutdown state and T1 is greater than T2, the operating frequency of the cold head (110) is reduced to a lower than the preset operating frequency.

9. The superconducting magnet cold head start adaptive system control method according to claim 8, characterized in that, Also includes: When the cold head (110) is detected to be in the start state and T1 is less than T2, the operating frequency of the cold head (110) is restored to the preset operating frequency.

10. The superconducting magnet cold head start adaptive system control method according to claim 8, characterized in that, When the cold head (110) is detected to be in a stopped state, and T1 is greater than T2, the operating frequency of the cold head (110) is reduced to below a preset operating frequency, specifically including: The control unit (140) receives a start command; The control unit (140) sends a low-frequency signal to the frequency converter (130) to control the drive motor (120) to be in a low-speed reciprocating motion state at the moment of startup.

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