High-temperature superconducting magnet system

Abstract

The invention discloses a high-temperature superconducting magnet system, which relates to the technical field of superconducting magnets, and is characterized by comprising a frequency converter, a high-temperature superconducting transformer, a low-temperature rectifier, a low-temperature low-resistance circuit breaker, a low-temperature low-resistance field effect switch, a sectional type high-temperature superconducting solenoid magnet and an energy release assembly, the frequency converter supplies power to the sectional type high-temperature superconducting solenoid magnet through the high-temperature superconducting transformer, the low-temperature rectifier, the low-temperature low-resistance circuit breaker and the low-temperature low-resistance field effect switch; the segmented high-temperature superconducting solenoid magnet is provided with a plurality of shunt taps which are connected in parallel, and a pair of shunt taps are correspondingly connected with the two ends of an energy release assembly through high-temperature superconducting energy release current leads which can be turned off to form an energy release loop with magnets connected in parallel. A traditional magnet binary current feeder line is omitted, heat leakage in the magnet excitation and normal operation process is greatly reduced, the excitation current of the magnet can be remarkably improved, the excitation voltage can be remarkably reduced, and the operation economical efficiency and inherent safety of the magnet are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting magnets, and more particularly to a high-temperature superconducting magnet system. Background Art

[0002] Thanks to the fact that superconducting materials have no DC resistance, they have the advantages of small size, low power consumption, and low operating cost when used in high-field magnets. In particular, the rapid development of high-temperature superconducting materials has given high-temperature superconducting magnets stronger technology and more suitable and broader application prospects. REBCO and Bi-based high-temperature superconductors have practical value at temperatures of 77K and below, and the lower the temperature, the higher the current density and practical magnetic field. Since the quench propagation speed of high-temperature superconductors is more than two orders of magnitude slower than that of low-temperature superconductors, high-temperature superconducting magnets are prone to heat concentration and burning after quenching, so optimizing the thermal stability of the magnet is the core issue to ensure the safe operation of the magnet.

[0003] For insulating superconducting magnets, the main method to improve the thermal stability of the magnet is to increase the conductor current, reduce the number of turns and inductance, which is beneficial to the rapid energy dissipation of the magnet and the improvement of the cooling efficiency of the magnet. With the increase of conductor current, the use of traditional power supply to power the magnet will lead to excessive heat leakage of the current lead of the magnet and rapid increase in the heating of the joint, which will seriously affect the economy of the construction and operation of the magnet power supply and cryogenic system. The current magnet system technology is difficult to achieve both performance advantages, economic advantages and reliability, which is one of the important reasons that limit the large-scale application of high-temperature superconducting magnets.

[0004] Therefore, how to study and design a high-temperature superconducting magnet system that can overcome the above-mentioned defects is a problem that we urgently need to solve. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a high-temperature superconducting magnet system, which adopts a high-temperature superconducting transformer, a low-temperature rectifier and a high-temperature superconducting current lead to supply power to the magnet, thereby eliminating the traditional magnet binary current feeder, greatly reducing the heat leakage during magnet excitation and normal operation, and can significantly increase the excitation current of the magnet, reduce the excitation voltage, and significantly improve the operating economy and inherent safety of the magnet.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: a high temperature superconducting magnet system, including a frequency converter, a high temperature superconducting transformer, a low temperature rectifier, a low temperature low resistance circuit breaker, a low temperature low resistance field effect switch, a segmented high temperature superconducting solenoid magnet and an energy dissipation component;

[0007] The output end of the frequency converter is connected to the input end of the high temperature superconducting transformer;

[0008] The output end of the high temperature superconducting transformer is connected to the input end of the low temperature rectifier;

[0009] The positive output end of the low-temperature rectifier is connected to the positive pole of the segmented high-temperature superconducting solenoid magnet through a low-temperature low-resistance circuit breaker, and the negative output end of the low-temperature rectifier is connected to the negative pole of the segmented high-temperature superconducting solenoid magnet through a low-temperature low-resistance field effect switch;

[0010] The segmented high-temperature superconducting solenoid magnet is provided with a plurality of parallel shunt taps, and a pair of shunt taps are respectively connected to the two ends of an energy dissipation component through switchable high-temperature superconducting energy dissipation current leads to form a magnet parallel energy dissipation circuit, so that the energy dissipation component absorbs the stored energy discharged when the magnet is abnormal.

[0011] Furthermore, the frequency converter converts the mains electricity into primary alternating current of set frequency and voltage, and supplies power to the primary of the high-temperature superconducting transformer via the copper current lead.

[0012] Furthermore, the low-temperature rectifier is composed of a high-temperature superconducting tape and a low-voltage field effect transistor, and is used to rectify the low-voltage and high-current alternating current output by the high-temperature superconducting transformer into direct current.

[0013] Furthermore, the low-temperature, low-resistance circuit breaker and / or the low-temperature, low-resistance field effect switch are connected to the low-temperature rectifier via a high-temperature superconducting current bus.

[0014] Furthermore, the low temperature and low resistance circuit breaker and / or the low temperature and low resistance field effect switch are connected to the segmented high temperature superconducting solenoid magnet through a high temperature superconducting variable temperature current lead.

[0015] Furthermore, the segmented high-temperature superconducting solenoid magnet is wound by an armored internally cooled high-temperature superconducting high-current conductor, and the shunt tap is located in the layer winding transposition interval at the end of the magnet.

[0016] Furthermore, the switchable high-temperature superconducting energy-draining current lead remains normally open under normal operating conditions and closes rapidly under abnormal operating conditions.

[0017] Furthermore, the energy dissipation component includes a high-resistance energy dissipation resistor, a low-resistance energy dissipation resistor and an IGBT switch; the low-resistance energy dissipation resistor and the IGBT switch are connected in series and then connected in parallel with the high-resistance energy dissipation resistor.

[0018] Furthermore, when the magnet is operating normally, the high-temperature superconducting transformer, low-temperature rectifier, high-temperature superconducting current bus, low-temperature low-resistance circuit breaker, low-temperature low-resistance field effect switch and high-temperature section of the high-temperature superconducting variable temperature current lead between the frequency converter and the segmented high-temperature superconducting solenoid magnet are cooled by forced flow of liquid nitrogen, and the temperature is maintained at 78-63K;

[0019] The low temperature section of the high temperature superconducting variable temperature current lead, the segmented high temperature superconducting solenoid magnet, and the low temperature section of the switchable high temperature superconducting energy dissipation current lead are cooled by forced flow of cold helium or liquid helium;

[0020] The temperature-variable section of the high-temperature superconducting temperature-variable current lead is cooled by conduction;

[0021] Furthermore, the low-temperature section of the switchable high-temperature superconducting energy dissipation current lead is injected with liquid nitrogen for cooling before the magnet is excited, and then cooled to solid nitrogen through conduction.

[0022] Furthermore, the system also includes a status monitoring and control module;

[0023] The state monitoring and control module is used to:

[0024] Monitor the temperature, voltage, magnetic field and stress state parameters of high-temperature superconducting magnets during magnet operation;

[0025] When an abnormality occurs, the high-temperature superconducting transformer, low-temperature rectifier, low-temperature low-resistance circuit breaker, low-temperature low-resistance field effect switch, turnable high-temperature superconducting energy dissipation current lead and energy dissipation component are controlled to change the working mode to achieve energy dissipation of the magnet.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. A high-temperature superconducting magnet system provided by the present invention adopts a high-temperature superconducting transformer, a low-temperature rectifier and a high-temperature superconducting current lead to supply power to the magnet, thereby eliminating the traditional binary current feeder of the magnet, greatly reducing the heat leakage during the magnet excitation and normal operation, and can significantly increase the excitation current of the magnet, reduce the excitation voltage, and significantly improve the operation economy and inherent safety of the magnet;

[0028] 2. The high-temperature superconducting transformer and low-temperature rectifier in the present invention can provide low-voltage and high-current for magnet excitation, which is much higher than the conventional power supply mode, and can greatly reduce the number of coil turns and inductance, and improve the protectability of the magnet;

[0029] 3. The power supply scheme of the frequency converter and high-temperature superconducting transformer in the present invention has a volume, construction and operation cost far lower than that of the traditional power supply and current feeder scheme. During high-frequency transformation, a higher excitation voltage can be provided to the magnet to increase the excitation rate. During constant magnetic field operation, low-frequency transformation can be used to intermittently compensate for the current loss caused by the joint and reduce the AC loss of the transformer.

[0030] 4. The high-temperature superconducting magnet in the present invention is connected in parallel with a normal temperature switch and an energy dissipation resistor through a high-temperature superconducting energy dissipation current lead that can be turned off. Since the heat leakage caused by the low-temperature vacuum circuit breaker is extremely low under normal conditions, multiple sections of parallel energy dissipation can be set for the high-temperature superconducting magnet, which can greatly increase the energy dissipation or energy transfer speed of the magnet and improve the reliability of the magnet quench protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0032] Figure 1 It is a working principle diagram in an embodiment of the present invention.

[0033] Marks and corresponding parts names in the attached drawings:

[0034] 1. Frequency converter; 2. Copper current lead; 3. High-temperature superconducting transformer; 4. Low-temperature rectifier; 5. High-temperature superconducting current busbar; 6. Low-temperature, low-resistance circuit breaker; 7. Low-temperature, low-resistance field effect switch; 8. High-temperature superconducting variable temperature current lead; 9. Segmented high-temperature superconducting solenoid magnet; 10. Turnable high-temperature superconducting energy-discharging current lead; 11. High-resistance energy-discharging resistor; 12. Low-resistance energy-discharging resistor; 13. IGBT switch. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0036] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to the other component.

[0037] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] Embodiment: A high temperature superconducting magnet system, such as Figure 1 As shown, it includes a frequency converter 1, a high temperature superconducting transformer 3, a low temperature rectifier 4, a low temperature low resistance circuit breaker 6, a low temperature low resistance field effect switch 7, a segmented high temperature superconducting solenoid magnet 9 and an energy dissipation component.

[0040] Among them, the output end of the inverter 1 is connected to the input end of the high-temperature superconducting transformer 3; the output end of the high-temperature superconducting transformer 3 is connected to the input end of the low-temperature rectifier 4; the positive output end of the low-temperature rectifier 4 is connected to the positive pole of the segmented high-temperature superconducting solenoid magnet 9 through a low-temperature and low-resistance circuit breaker 6, and the negative output end of the low-temperature rectifier 4 is connected to the negative pole of the segmented high-temperature superconducting solenoid magnet 9 through a low-temperature and low-resistance field effect switch 7; the segmented high-temperature superconducting solenoid magnet 9 is provided with a plurality of parallel shunt taps, and a pair of shunt taps are respectively connected to the two ends of an energy dissipation component through a switchable high-temperature superconducting energy dissipation current lead 10 to form a magnet parallel energy dissipation circuit, so that the energy dissipation component absorbs the stored energy discharged when the magnet is abnormal.

[0041] The present invention converts the mains electricity into AC with set frequency and voltage through the frequency converter 1, supplies power to the primary of the high-temperature superconducting transformer 3, and the high-temperature superconducting transformer 3 converts the high-voltage AC into low-voltage and high-current AC; the low-temperature rectifier 4 further rectifies the low-voltage and high-current AC into DC, and the DC is supplied to the segmented high-temperature superconducting solenoid magnet 9 through the low-temperature and low-resistance circuit breaker 6 and the low-temperature and low-resistance field effect switch 7, and the high-temperature superconducting solenoid magnet generates a stable strong magnetic field. The high-temperature superconducting magnet is connected to the energy dissipation component through multiple pairs of switchable high-temperature superconducting energy dissipation current leads 10, and the energy dissipation component is used to absorb the stored energy discharged when the magnet is abnormal.

[0042] In this embodiment, the inverter 1 is a conventional single-phase inverter 1, the operating parameters of the inverter 1 are 220V, 120A, frequency 0-500Hz, and it operates at room temperature. The primary of the high-temperature superconducting transformer 3 is powered through the copper current lead 2. The power supply end of the copper current lead 2 is at room temperature and the transformer end is at a low temperature of 78-63K. The output voltage of the power supply is proportional to the frequency, and the primary voltage of the transformer is adjusted by adjusting the frequency.

[0043] The high temperature superconducting transformer 3 can adopt a high transformation ratio transformer, with typical values ​​of 0.1-10V, 1-100kA, immersed in liquid nitrogen, and operating temperature of 78-63K, to convert the primary high voltage AC into the secondary low voltage and high current AC. Since the primary current of the transformer is small, the heating and heat leakage of the system are greatly reduced.

[0044] In this embodiment, the low-temperature rectifier 4 is composed of REBCO high-temperature superconducting tape and low-voltage field effect tube, and the input end is connected to the secondary output of the high-temperature superconducting transformer 3 to rectify the low-voltage high-current AC into DC. The low-temperature rectifier 4 is immersed in liquid nitrogen and the operating temperature is 78-63K. Since the voltage loss of the low-temperature superconducting rectifier can be controlled below 6mV, the required refrigeration power is much lower than the power required by the same level current lead and conventional rectifier circuit, achieving energy saving and cost reduction.

[0045] In addition, the low temperature and low resistance circuit breaker 6 and the low temperature and low resistance field effect switch 7 are connected to the low temperature rectifier 4 through the high temperature superconducting current bus 5. The low temperature and low resistance circuit breaker 6 and the low temperature and low resistance field effect switch 7 are connected to the segmented high temperature superconducting solenoid magnet 9 through the high temperature superconducting variable temperature current lead 8.

[0046] Specifically, one end of the positive high-temperature superconducting current busbar 5 is connected to the positive output end of the low-temperature rectifier 4, and the other end is connected to the input connector of the low-temperature low-resistance circuit breaker 6; one end of the negative high-temperature superconducting current busbar 5 is connected to the negative output end of the low-temperature rectifier 4, and the other end is connected to the input end of the low-temperature low-resistance field effect switch 7. The normal operating temperature is 78-63K. The high-temperature superconducting current busbar 5 keeps the high-temperature superconducting transformer 3 and the low-temperature rectifier 4 away from the magnet and is not affected by the strong magnetic field.

[0047] The output connector of the low-temperature and low-resistance circuit breaker 6 is connected to the high-temperature superconducting variable temperature current lead 8 of the positive pole; the output end of the low-temperature and low-resistance field effect switch 7 is connected to the high-temperature superconducting variable temperature current lead 8 of the negative pole. The high-temperature superconducting variable temperature current lead 8 realizes the transition from the liquid nitrogen temperature zone to the lower temperature zone, with the operating temperature of the high-temperature end being 78-63K and the lowest operating temperature of the low-temperature section being 4.2K. The variable temperature current lead is further connected to the positive and negative poles of the high-temperature superconducting magnet.

[0048] It should be noted that the low temperature and low resistance circuit breaker 6 can be a vacuum circuit breaker with low temperature and low resistance characteristics in the prior art, and can be selected according to actual needs. The low temperature and low resistance field effect switch 7 can also be a field effect switch with low temperature and low resistance characteristics in the prior art, and can be selected according to actual needs.

[0049] The segmented high-temperature superconducting solenoid magnet 9 is wound by an armored internally cooled high-temperature superconducting high-current conductor. The magnet has multiple parallel shunt taps, which are located in the layer winding transposition interval at the end of the magnet. The minimum operating temperature is 4.2K, which is used to stably generate a strong magnetic field.

[0050] The segmented high-temperature superconducting solenoid magnet 9 has an operating current of 20 kA and a self-inductance of 0.1 H. Eight switchable high-temperature superconducting energy-discharging current leads 10 are provided to divide the magnet into seven segments, wherein the first and last energy-discharging current leads are connected in parallel with the variable temperature current lead.

[0051] It should be noted that the innovation of the magnet is that the magnet is divided into multiple sections by a shunt tap, so the segmented high-temperature superconducting solenoid magnet 9 can also be replaced by a magnet wound in other forms, such as a folded type.

[0052] A plurality of switchable high-temperature superconducting energy-discharging current leads 10 are connected to a plurality of parallel shunt taps of the magnet. Under normal working conditions, the switchable high-temperature superconducting energy-discharging current leads 10 remain normally open, the connection end with the magnet remains at a low temperature, the connection end of the energy-discharging circuit remains at room temperature, and the circuit breaker in the vacuum isolates the low temperature from the room temperature end, with only a weak structural heat leakage, which is less than 0.15W; under abnormal working conditions, the switchable high-temperature superconducting energy-discharging current leads 10 close quickly, and the current leads heat up under the heating of Joule heat and conduction heat, and rely on the stored fixed nitrogen to absorb the Joule heat during the heating, so as to complete the magnet performance within the temperature safety range, and the maximum temperature in the liquid nitrogen (fixed nitrogen) zone is less than 80K.

[0053] As an optional implementation, the energy dissipation component includes a high-resistance energy dissipation resistor 11, a low-resistance energy dissipation resistor 12 and an IGBT switch 13; the low-resistance energy dissipation resistor 12 and the IGBT switch 13 are connected in series and then connected in parallel with the high-resistance energy dissipation resistor 11. Under normal working conditions of the magnet, the switch and the energy dissipation resistor do not work. Under the energy dissipation working condition, the switch is turned on according to a preset mode, and the magnet energy dissipation is completed through the energy dissipation resistor.

[0054] It should be noted that the energy dissipation component may also adopt other structures having the above-mentioned operating characteristics composed of one or more energy dissipation resistors and switches, and its specific connection method is not limited.

[0055] When the magnet operates normally, the high-temperature superconducting transformer 3, the low-temperature rectifier 4, the high-temperature superconducting current busbar 5, the low-temperature low-resistance circuit breaker 6, the low-temperature low-resistance field effect switch 7 and the high-temperature section of the high-temperature superconducting variable temperature current lead 8 between the inverter 1 and the segmented high-temperature superconducting solenoid magnet 9 are cooled by forced flow of liquid nitrogen, and the temperature is maintained at 78-63K; the low-temperature section of the high-temperature superconducting variable temperature current lead 8, the segmented high-temperature superconducting solenoid magnet 9, and the low-temperature section of the switchable high-temperature superconducting energy discharge current lead 10 are cooled by forced flow of cold helium or liquid helium; the variable temperature section of the high-temperature superconducting variable temperature current lead 8 is cooled by conduction; and the low-temperature section of the switchable high-temperature superconducting energy discharge current lead 10 is injected with liquid nitrogen for cooling before the magnet is excited, and then cooled to solid nitrogen by conduction.

[0056] A high-temperature superconducting magnet system described in the present invention also includes a state monitoring and control module; the state monitoring and control module is used to monitor the temperature, voltage, magnetic field and stress state parameters of the high-temperature superconducting magnet during the operation of the magnet; and when an abnormality occurs, the high-temperature superconducting transformer 3, the low-temperature rectifier 4, the low-temperature low-resistance circuit breaker 6, the low-temperature low-resistance field effect switch 7, the turnable high-temperature superconducting energy dissipation current lead 10 and the energy dissipation component are controlled to change the working mode to achieve energy dissipation of the magnet.

[0057] In this implementation case, the energy dissipation speed of the segmented high-temperature superconducting magnet quench protection is more than 10 times higher than that of the unsegmented one, which greatly improves the reliability of the magnet quench protection. In addition, when the 4.2K heat load of the high-temperature superconducting variable temperature current lead 8 and the joint is the same as the traditional power supply scheme for the magnet, the 77K heat load can be reduced from the minimum of about 1400W of the traditional scheme to about 200W. Although the 4.2K heat load is increased by about 1.2W due to the high-temperature superconducting energy dissipation current lead, the overall power of the required GM refrigerator is still reduced by more than 20kW, which significantly reduces the operating cost.

[0058] Working principle: The present invention adopts a high-temperature superconducting transformer 3, a low-temperature rectifier 4 and a high-temperature superconducting current lead to supply power to the magnet, eliminating the traditional binary current feeder of the magnet, greatly reducing the heat leakage during the excitation and normal operation of the magnet, and can significantly increase the excitation current of the magnet, reduce the excitation voltage, and significantly improve the operation economy and inherent safety of the magnet; the high-temperature superconducting transformer 3 and the low-temperature rectifier 4 in the present invention can provide a low-voltage and high-current for magnet excitation that is much higher than the conventional power supply method, which can greatly reduce the number of coil turns and inductance, and improve the protectability of the magnet; the high-temperature superconducting magnet in the present invention is connected in parallel with the normal temperature switch and the energy discharge resistor through a high-temperature superconducting energy discharge current lead 10 that can be turned off. Since the heat leakage caused by the low-temperature vacuum circuit breaker is extremely low under normal conditions, multiple sections of parallel energy discharge can be set for the high-temperature superconducting magnet, which can greatly improve the energy discharge or energy transfer speed of the magnet and improve the reliability of the magnet quench protection.

[0059] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high temperature superconducting magnet system, characterized in that: It comprises a frequency converter (1), a high temperature superconducting transformer (3), a low temperature rectifier (4), a low temperature low resistance circuit breaker (6), a low temperature low resistance field effect switch (7), a segmented high temperature superconducting solenoid magnet (9) and an energy dissipation component; The output end of the frequency converter (1) is connected to the input end of the high temperature superconducting transformer (3); The output end of the high temperature superconducting transformer (3) is connected to the input end of the low temperature rectifier (4); The positive output end of the low-temperature rectifier (4) is connected to the positive pole of the segmented high-temperature superconducting solenoid magnet (9) through a low-temperature low-resistance circuit breaker (6), and the negative output end of the low-temperature rectifier (4) is connected to the negative pole of the segmented high-temperature superconducting solenoid magnet (9) through a low-temperature low-resistance field effect switch (7); The segmented high-temperature superconducting solenoid magnet (9) is provided with a plurality of parallel shunt taps, and a pair of shunt taps are respectively connected to two ends of an energy dissipation component through switchable high-temperature superconducting energy dissipation current leads (10) to form a magnet parallel energy dissipation circuit, so that the energy dissipation component absorbs stored energy discharged when the magnet is abnormal.

2. A high temperature superconducting magnet system according to claim 1, characterized in that: The frequency converter (1) converts the city electricity into primary alternating current of set frequency and voltage, and supplies the primary power to the high-temperature superconducting transformer (3) via the copper current lead (2).

3. A high temperature superconducting magnet system according to claim 1, characterized in that: The low-temperature rectifier (4) is composed of a high-temperature superconducting tape and a low-voltage field effect transistor, and is used to rectify the low-voltage, high-current alternating current output by the high-temperature superconducting transformer (3) into direct current.

4. A high temperature superconducting magnet system according to claim 1, characterized in that: The low-temperature, low-resistance circuit breaker (6) and / or the low-temperature, low-resistance field effect switch (7) are connected to the low-temperature rectifier (4) via a high-temperature superconducting current busbar (5).

5. A high temperature superconducting magnet system according to claim 1, characterized in that: The low-temperature, low-resistance circuit breaker (6) and / or the low-temperature, low-resistance field effect switch (7) are connected to a segmented high-temperature superconducting solenoid magnet (9) via a high-temperature superconducting variable-temperature current lead (8).

6. A high temperature superconducting magnet system according to claim 1, characterized in that: The segmented high-temperature superconducting solenoid magnet (9) is formed by winding an armored internally cooled high-temperature superconducting high-current conductor, and the shunt tap is located in the layer winding transposition interval at the end of the magnet.

7. A high temperature superconducting magnet system according to claim 1, characterized in that: The switchable high-temperature superconducting energy-discharging current lead (10) remains normally open under normal working conditions and quickly closes under abnormal working conditions.

8. A high temperature superconducting magnet system according to claim 1, characterized in that: The energy dissipation component comprises a high-resistance energy dissipation resistor (11), a low-resistance energy dissipation resistor (12) and an IGBT switch (13); the low-resistance energy dissipation resistor (12) and the IGBT switch (13) are connected in series and then connected in parallel with the high-resistance energy dissipation resistor (11).

9. A high temperature superconducting magnet system according to claim 1, characterized in that: When the magnet is operating normally, the high-temperature superconducting transformer (3), the low-temperature rectifier (4), the high-temperature superconducting current busbar (5), the low-temperature low-resistance circuit breaker (6), the low-temperature low-resistance field effect switch (7) and the high-temperature section of the high-temperature superconducting variable temperature current lead (8) between the frequency converter (1) and the segmented high-temperature superconducting solenoid magnet (9) are cooled by forced flow of liquid nitrogen, and the temperature is maintained at 78-63K; The low temperature section of the high temperature superconducting variable temperature current lead (8), the segmented high temperature superconducting solenoid magnet (9), and the low temperature section of the switchable high temperature superconducting energy dissipation current lead (10) are cooled by forced flow of cold helium gas or liquid helium; The temperature-variable section of the high-temperature superconducting temperature-variable current lead (8) is cooled by conduction; Furthermore, the low-temperature section of the switchable high-temperature superconducting energy-discharging current lead (10) is injected with liquid nitrogen for cooling before the magnet is excited, and then cooled to solid nitrogen through conduction cooling.

10. A high temperature superconducting magnet system according to claim 1, characterized in that: The system also includes a status monitoring and control module; The state monitoring and control module is used to: Monitor the temperature, voltage, magnetic field and stress state parameters of high-temperature superconducting magnets during magnet operation; When an abnormality occurs, the high-temperature superconducting transformer (3), the low-temperature rectifier (4), the low-temperature low-resistance circuit breaker (6), the low-temperature low-resistance field effect switch (7), the switchable high-temperature superconducting energy dissipation current lead (10) and the energy dissipation component are controlled to change the working mode to achieve energy dissipation of the magnet.

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