A conduction-cooled high-temperature superconducting electric suspension magnet structure

Abstract

The invention discloses a conduction-cooled high-temperature superconducting electric suspension magnet structure, which includes a low-temperature container, a high-temperature superconducting magnet is arranged in the low-temperature container, and the high-temperature superconducting magnet includes a coil box, which is encapsulated by a coil cover, and a plurality of layers of high-temperature superconducting coils stacked on each other are arranged in the coil box, and the high-temperature superconducting coils are separated by a conduction cooling plate; the inner side and the outer side of the high-temperature superconducting coil are respectively provided with an inner aluminum block and an outer aluminum block, the inner aluminum block is sleeved on the coil skeleton, and a fastener is arranged outside the outer aluminum block; the coil box is fixed on the magnet force transmission rod, and a push rod is arranged in the magnet force transmission rod, one end of the push rod contacts the thin wall surface of the low-temperature container, and the other end of the push rod passes through the thick wall surface of the low-temperature container and is connected to the support mechanism. The invention realizes the detachable assembly and disassembly of the high-temperature superconducting electric suspension magnet in the low-temperature container, limits the deformation amount of the low-temperature container, improves the temperature distribution uniformity of the high-temperature superconducting magnet, and reduces the number of joints when the high-temperature superconducting magnet is in closed-loop operation.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic suspension, and in particular to a conduction-cooled high-temperature superconducting electric suspension magnet structure. Background Art

[0002] Superconducting electric magnetic levitation technology has passed the test of manned operation at a speed of 603 kilometers per hour and is one of the main development directions of future ultra-high-speed ground rail transit technology.

[0003] The core component of a superconducting electric maglev train is the onboard superconducting magnet, which is divided into onboard low-temperature superconducting magnets and onboard high-temperature superconducting magnets. Low-temperature superconducting magnets need to be cooled by liquid helium (4.2K), and their low-temperature structure is complex and the refrigeration cost is high; high-temperature superconducting magnets can be cooled by liquid nitrogen (77K), solid nitrogen and refrigerator conduction, and their low-temperature structure is relatively simple and the refrigeration cost is low. Therefore, high-temperature superconducting magnets have more application prospects in electric maglev trains.

[0004] High-temperature superconducting materials have strong current carrying capacity in the temperature range of 20-50K. The temperature of liquid nitrogen is 77K, which cannot make high-temperature superconducting magnets fully exert their superconducting properties. Solid nitrogen can provide a temperature environment of 20-50K for high-temperature superconducting magnets, but the cooling time of solid nitrogen is long and the mechanical properties are poor. Refrigerator conduction cooling can make high-temperature superconducting magnets work in the temperature range of 20-50K, and the cooling time is shorter and the low-temperature structure is simpler than that of solid nitrogen cooling. Therefore, the refrigerator conduction cooling method is more suitable for high-temperature superconducting magnets.

[0005] The working conditions of the onboard superconducting magnets in electric magnetic levitation are very complex. There are not only electromagnetic disturbances from the ground track coils and the metal components in the onboard cryogenic container, but also random vibrations of the train body during operation. Therefore, in order to improve the stability of the conduction-cooled high-temperature superconducting electric levitation magnet system, the following problems need to be solved:

[0006] (1) How to improve the uniformity of temperature distribution of superconducting magnets;

[0007] (2) How is the electromagnetic force of the superconducting magnet transmitted to the cryogenic container?

[0008] (3) How to reduce the closed-loop operating resistance of superconducting magnets;

[0009] (4) How to limit the deformation of the cryogenic container.

[0010] In view of these problems, the present invention proposes a conduction-cooled high-temperature superconducting electric suspension magnet and a cryogenic structure thereof. Summary of the invention

[0011] In view of the above-mentioned deficiencies in the prior art, the present invention provides a conduction-cooled high-temperature superconducting electric suspension magnet structure, which realizes the detachable assembly and disassembly of the electric suspension magnet in a cryogenic container, limits the deformation of the cryogenic container, improves the uniformity of the temperature distribution of the superconducting magnet, and reduces the number of joints during the closed-loop operation of the high-temperature superconducting electric suspension magnet.

[0012] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0013] Provided is a conduction-cooled high-temperature superconducting electric suspension magnet structure, comprising a cryogenic container, a high-temperature superconducting magnet arranged in the cryogenic container, the high-temperature superconducting magnet comprising a coil box, the coil box being packaged by a coil cover, a plurality of layers of high-temperature superconducting coils stacked on each other arranged in the coil box, each layer of high-temperature superconducting coils being separated by a conduction cooling plate; an inner aluminum block and an outer aluminum block are respectively arranged on the inner side and the outer side of the high-temperature superconducting coil, the inner aluminum block is sleeved on the coil skeleton, and a fastener is arranged outside the outer aluminum block; the coil box is fixed on a magnet force transmission rod, a push rod is arranged in the magnet force transmission rod, one end of the push rod is in contact with a thin wall surface of the cryogenic container, and the other end of the push rod passes through a thick wall surface of the cryogenic container and is connected to a supporting mechanism.

[0014] Furthermore, the thickness of the thick wall surface is greater than that of the thin wall surface, a sealing ring is provided at the connection between the thin wall surface and the thick wall surface, and the thin wall surface and the thick wall surface are connected by screws.

[0015] Furthermore, a plurality of high temperature superconducting coils are connected in series, and surfaces of the cold plate, the inner aluminum block and the outer aluminum block are all provided with insulating layers.

[0016] Furthermore, an indium sheet or thermal conductive silicone grease is applied to the contact surface between the coil box and the coil cover to improve the cooling effect.

[0017] Furthermore, the center of the high temperature superconducting magnet is hollowed out to form a central hole.

[0018] Furthermore, the supporting mechanism includes a fixed flange, a force transmission flange and a sealing flange fixed on the thick wall surface. The magnet force transmission rod and the push rod pass through the fixed flange and are fixedly connected to the force transmission flange. The force transmission flange is arranged in the sealing flange. The force transmission flange and the sealing flange are both connected to the fixed flange by bolts.

[0019] Furthermore, a sealing ring is arranged between the sealing flange and the fixing flange.

[0020] Furthermore, the magnet force transmission rod is connected to the coil box and the force transmission flange by threaded connection.

[0021] Furthermore, a number of cold plates are arranged on the coil cover, the cold plates are evenly distributed, the cold plates are connected by cold belts, the cold plates are connected to the cold head of the refrigerator by cold belts, a cold screen is arranged outside the high-temperature superconducting magnet, the cold screen is connected to the cold head of the refrigerator, and the magnet force transmission rod and the cold plate are connected by a cold belt.

[0022] Furthermore, the high-temperature superconducting coil is welded to a superconducting switch for realizing its closed-loop operation, and the superconducting switch is wound by an inlet terminal or an outlet terminal of the high-temperature superconducting coil.

[0023] The beneficial effects of the present invention are:

[0024] 1. The high-temperature superconducting coil can be disassembled in the cryogenic container. The high-temperature superconducting coil is fixed in the coil box by screw connection, so that the high-temperature superconducting coil can be disassembled in the coil box; the high-temperature superconducting magnet is enclosed in the cryogenic container by bolt connection, and the thin wall and thick wall of the cryogenic container are connected by screws, so that the high-temperature superconducting magnet can be disassembled in the cryogenic container.

[0025] 2. The deformation of the cryogenic container is small. One end of the ejector pin is fixedly connected to the force transmission flange, and the other end is in contact with the thin wall of the cryogenic container. When the cryogenic container is evacuated, the atmospheric pressure forces the cryogenic container to deform, and this deformation will cause the ejector pin of the cryogenic container to generate a reaction force, preventing the container from further deforming.

[0026] 3. The temperature distribution uniformity of the high-temperature superconducting magnet is good. The coil cover is evenly arranged with cold plates, which are connected by cold belts, and the cold plates are connected to the cold head of the refrigerator by cold belts. The cold source of the refrigerator will be effectively transferred to the superconducting magnet through the cold plates and cold belts, which improves the cooling rate and temperature distribution uniformity of the superconducting magnet.

[0027] 4. The number of joints is small when the high-temperature superconducting magnet is in closed-loop operation. The superconducting switch of the high-temperature superconducting magnet is wound with the inlet or outlet of the high-temperature superconducting coil. Therefore, there is only one joint between each high-temperature superconducting coil and its corresponding superconducting switch, which reduces the resistance of the high-temperature superconducting coil when it is in closed-loop operation.

[0028] In summary, the present invention realizes the detachable assembly of a high-temperature superconducting electric suspension magnet in a cryogenic container, limits the deformation of the cryogenic container, improves the uniformity of the temperature distribution of the superconducting magnet, and reduces the number of joints during the closed-loop operation of the high-temperature superconducting magnet. The present invention has good application prospects in ultra-high-speed magnetic levitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A cross-sectional view of the conduction-cooled high-temperature superconducting electric suspension magnet structure.

[0030] Figure 2This is a front view of the conduction-cooled high-temperature superconducting electric suspension magnet structure.

[0031] Figure 3 This is the closed-loop operation principle diagram of the conduction-cooled high-temperature superconducting electric suspension magnet structure.

[0032] Figure 4 This is a simulation result of the deformation of the conduction-cooled high-temperature superconducting electric suspension magnet structure after vacuuming.

[0033] Figure 5 This is a diagram showing the stress distribution simulation results of a conduction-cooled high-temperature superconducting electric suspension magnet structure under load conditions.

[0034] Figure 6 This is a diagram showing the simulation results of the temperature distribution of a conduction-cooled high-temperature superconducting electric suspension magnet structure under load conditions.

[0035] Among them, 1. cold plate, 2. high-temperature superconducting coil, 3. inner aluminum block, 4. coil frame, 5. coil box, 6. outer aluminum block, 7. fasteners, 8. screws, 9. coil cover, 10. fixing flange, 11. bolts, 12. sealing ring, 13. sealing flange, 14. force transmission flange, 15. cold shield, 16. low-temperature container, 16a. thin wall of low-temperature container, 16b. thick wall of low-temperature container, 17. high-temperature superconducting magnet, 18. center hole , 19. Push rod, 20. Magnet force transmission rod, 21. Refrigerator, 22. First-stage cold head, 23. Second-stage cold head, 24. Cold conduction belt, 25. Left incoming line terminal, 26. Conductive copper block, 27. High-temperature superconducting current lead, 28. Copper electrode, 29. Superconducting switch, 30. Left joint, 31. High-temperature superconducting tape, 32. Left outgoing line terminal, 33. Copper bridge, 34. Right outgoing line terminal, 35. Heater, 36. Right joint, 37. Right incoming line terminal. DETAILED DESCRIPTION

[0036] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0037] like Figures 1 to 3 As shown, the conduction-cooled high-temperature superconducting electric suspension magnet structure of the present scheme includes a low-temperature container 16, in which a high-temperature superconducting magnet 17 is arranged, and the high-temperature superconducting magnet 17 includes a coil box 5, which is encapsulated by a coil cover 9, and in which a plurality of layers of high-temperature superconducting coils 2 stacked on each other are arranged, and each layer of high-temperature superconducting coils 2 is separated by a conduction cooling plate 1.

[0038] An inner aluminum block 3 and an outer aluminum block 6 are respectively arranged on the inner and outer sides of the high-temperature superconducting coil 2. The inner aluminum block 3 is sleeved on the coil frame 4, and a fastener 7 is arranged on the outside of the outer aluminum block 6. The coil box 5 is fixed to the magnet force transmission rod 20 by threaded connection. A push rod 19 is arranged inside the magnet force transmission rod 20. One end of the push rod 19 contacts the thin wall surface 16a of the low-temperature container, and the other end of the push rod 19 passes through the thick wall surface 16b of the low-temperature container and is connected to the supporting mechanism.

[0039] The cooling plate 1 is a copper plate, which enhances the cooling effect between the layers of high-temperature superconducting coils 2 stacked on each other; the high-temperature superconducting coils 2 are wound with second-generation high-temperature superconducting tapes; the inner aluminum block 3 and the outer aluminum block 6 are made of high-purity aluminum, which plays a role in relieving the radial stress of the high-temperature superconducting coils 2. The coil skeleton 4 and the fastener 7 are made of high-strength glass fiber material to resist the cold contraction stress and strain of the high-temperature superconducting magnet 17; the coil box 5 and the coil cover 9 are made of aluminum alloy material to enhance the cooling effect of the high-temperature superconducting magnet 17, and a center hole 18 is provided in the high-temperature superconducting magnet 17 to reduce the overall weight of the high-temperature superconducting magnet 17.

[0040] The cryogenic container 16 includes a thin-walled surface 16a and a thick-walled surface 16b. The thickness of the thick-walled surface 16b is greater than that of the thin-walled surface 16a. A sealing ring 12 is provided at the connection between the thin-walled surface 16a and the thick-walled surface 16b. The thin-walled surface 16a and the thick-walled surface 16b are connected by screws 8.

[0041] The supporting mechanism includes a fixed flange 10, a force transmission flange 14 and a sealing flange 13 fixed to the thick wall surface 16b of the low-temperature container. The magnetic force transmission rod 20 and the push rod 19 pass through the fixed flange 10 and are fixedly connected to the force transmission flange 14. The force transmission flange 14 is arranged in the sealing flange 13. The force transmission flange 14 and the sealing flange 13 are connected to the fixed flange 10 by bolts 11; a sealing ring 12 is arranged between the sealing flange 13 and the fixed flange 10.

[0042] A number of cold plates 1 are also arranged on the coil cover 9, and the cold plates 1 are connected to each other through a cold belt 24. The cold plate 1 is connected to the secondary cold head 23 of the refrigerator 21 through the cold belt 24. A cold shield 15 is arranged outside the high-temperature superconducting magnet 17, and the cold shield 15 is connected to the primary cold head 22 of the refrigerator 21. The magnet force transmission rod 20 is connected to the cold plate 1 by a cold belt 24.

[0043] Several high-temperature superconducting coils 2 are connected in series, and the surfaces of the cooling plate 1, the inner aluminum block 3 and the outer aluminum block 6 are all provided with an insulating layer; the contact surface between the coil box 5 and the coil cover 9 is affixed with an indium sheet or coated with thermal conductive silicone grease to improve the cooling effect.

[0044] The low-temperature container 16 is made of aluminum alloy, the thickness of the thin wall 16a of the low-temperature container is about 4 mm, and the thickness of the thick wall 16b of the low-temperature container is about 10 mm; the cold shield 15 is made of copper with good thermal conductivity and has a thickness of about 1 mm; the top rod 19 and the force transmission flange 14 are made of titanium alloy to enhance their bending strength; the magnet force transmission rod 20 is made of high-strength glass fiber to reduce its conduction heat leakage and enhance its bending strength; the fixing flange 10 and the sealing flange 13 are made of aluminum alloy; the outer surfaces of the magnet force transmission rod 20, the top rod 19 and the cold shield 15 are all affixed with multiple layers of super insulation material to reduce radiation heat leakage.

[0045] After the cryogenic container 16 is evacuated, the cryogenic container 16 is deformed under the action of atmospheric pressure, and the force on the thin wall surface 16a of the cryogenic container is transmitted to the force transmission flange 14 through the top rod 19, thereby preventing the further deformation of the thin wall surface 16a of the cryogenic container. During the cooling, excitation and external disturbance of the high-temperature superconducting magnet 17, the force applied to the high-temperature superconducting magnet 17 will first be transmitted to the force transmission flange 14 through the magnet force transmission rod 20, and then transmitted to the fixing flange 10 through the bolt 11, and finally act on the thick wall surface 16b of the cryogenic container. Because the force transmission flange 14 is sealed in the sealing flange 13, the deformation of the force transmission flange 14 after being subjected to force will not affect the sealing of the cryogenic container 16.

[0046] The refrigerator 21 transfers the cold source to the cold shield 15 through the first-stage cold head 22, and transfers the cold source to the cold plate 1 through the second-stage cold head 23. The cold plate 1 then transfers the cold source to the magnet force transmission rod 20 and the coil cover 9. The coil cover 9 then transfers the cold source to the coil box 5, and finally to the inner aluminum block 3, the outer aluminum block 6 and the high-temperature superconducting coil 2. The cold plate 1 is evenly arranged on the coil cover 9, ensuring uniform temperature distribution in the coil cover 9 and the coil box 5; and because the high-temperature superconducting coil 2 is surrounded by the cold plate 1, the inner aluminum block 3 and the outer aluminum block 6, the temperature difference in the high-temperature superconducting coil 2 is small.

[0047] The superconducting switch 29 is wound by using the left inlet terminal 25 and the right outlet terminal 34 of the high-temperature superconducting coil 2. The other end of the superconducting switch 29 is welded to the left outlet terminal 32 and the right inlet terminal 37 of the high-temperature superconducting coil 2 to form a left joint 30 and a right joint 36 respectively. The left joint 30 and the right inlet terminal 37 are both welded to the copper bridge 33. A plurality of high-temperature superconducting tapes 31 connected in parallel are arranged on the upper surface of the copper bridge 33 to reduce the resistance of the copper bridge. A heater 35 is arranged on the lower surface of the superconducting switch 29. The two ends of the high-temperature superconducting current lead 27 are respectively connected to the copper electrode 28 and the conductive copper block 26. The left inlet terminal 25 and the right outlet terminal 34 of the high-temperature superconducting coil 2 are both welded to the conductive copper block 26.

[0048] The closed-loop operation process of the high-temperature superconducting magnet 17 is as follows: start the heater 35 to put the superconducting switch 29 in a quenched state, excite the high-temperature superconducting magnet 17, and the current will flow in direction ①; after the excitation current is reached and the magnetic field is stable, turn off the heater 35, and after the superconducting switch 29 returns to the superconducting state, gradually reduce the excitation current until the excitation current is 0; disconnect the external power supply, the high-temperature superconducting magnet 17 works in a closed-loop mode, and the current will flow in direction ②.

[0049] Figure 4 , Figure 5 and Figure 6 This is the simulation result of the present invention. Figure 4 It shows that the maximum deformation of the cryogenic container 16 after evacuation is only 1.31 mm, and the maximum deformation position appears on the thin wall surface 16a of the cryogenic container. Figure 5 It shows that the maximum temperature difference of the high temperature superconducting magnet 17 is less than 0.1K and the temperature distribution uniformity is good. Figure 6 It shows that under load conditions, the maximum stress of the high-temperature superconducting magnet is less than 300MPa, which meets the strength design requirements.

[0050] The high temperature superconducting coil 2 of the present invention can be disassembled in the low temperature container 16. The high temperature superconducting coil 2 is fixed in the coil box 5 by screws 8, so that the high temperature superconducting coil 2 can be disassembled in the coil box 5; the high temperature superconducting magnet 17 is sealed in the low temperature container 16 by bolts 11, and the thin wall surface 16a and the thick wall surface 16b of the low temperature container are connected by screws 8, so that the high temperature superconducting magnet 17 can be disassembled in the low temperature container 16.

[0051] The low temperature container 16 of the present invention has a small deformation. One end of the push rod 19 is fixedly connected to the force transmission flange 14, and the other end is in contact with the thin wall surface 16a of the low temperature container; when the low temperature container 16 is evacuated, the atmospheric pressure forces the low temperature container 16 to deform, and the deformation causes the push rod 19 to generate a reaction force, which hinders the further deformation of the low temperature container 16.

[0052] The temperature distribution uniformity of the high-temperature superconducting magnet 17 of the present invention is good. The coil cover 9 is evenly arranged with cooling plates 1, which are connected by cooling belts 24, and the cooling plates 1 are connected to the secondary cold head 23 of the refrigerator by the cooling belt 24. The cold source of the refrigerator 21 will be effectively transferred to the high-temperature superconducting magnet 17 through the cooling plates 1 and the cooling belt 24, thereby improving the cooling rate of the superconducting magnet 17 and the uniformity of its temperature distribution.

[0053] The high temperature superconducting magnet 17 of the present invention has a small number of joints when in closed loop operation. The superconducting switch 29 of the high temperature superconducting magnet 17 is wound with the left inlet terminal 25 and the right outlet terminal 34 of the high temperature superconducting coil 2. Therefore, there is only one joint between each high temperature superconducting coil 2 and its corresponding superconducting switch 29, which reduces the resistance of the high temperature superconducting coil 2 when in closed loop operation.

[0054] In summary, the present invention realizes the detachable assembly of the high-temperature superconducting electric suspension magnet in the cryogenic container 16, limits the deformation of the cryogenic container 16, improves the uniformity of the temperature distribution of the high-temperature superconducting magnet 17, and reduces the number of joints during the closed-loop operation of the high-temperature superconducting magnet 17. The present invention has broad application prospects in ultra-high-speed magnetic levitation.

Claims

1. A conduction-cooled high-temperature superconducting electric suspension magnet structure, characterized in that: The invention comprises a low temperature container (16), wherein a high temperature superconducting magnet (17) is arranged in the low temperature container (16), wherein the high temperature superconducting magnet (17) comprises a coil box (5), wherein the coil box (5) is encapsulated by a coil cover (9), wherein a plurality of layers of high temperature superconducting coils (2) stacked on each other are arranged in the coil box (5), wherein each layer of the high temperature superconducting coils (2) is separated by a cold plate (1); and inner aluminum blocks (3) are respectively arranged on the inner side and the outer side of the high temperature superconducting coil (2). and an outer aluminum block (6), the inner aluminum block (3) being sleeved on the coil frame (4), the outer aluminum block (6) being provided with a fastener (7); the coil box (5) being fixed on the magnet force transmission rod (20), the magnet force transmission rod (20) being provided with a push rod (19), one end of the push rod (19) being in contact with the thin wall surface (16a) of the low temperature container (16), and the other end of the push rod (19) passing through the thick wall surface (16b) of the low temperature container (16) and being connected to the supporting mechanism; The center of the high-temperature superconducting magnet (17) is hollowed out to form a center hole (18); The support mechanism comprises a fixed flange (10), a force transmission flange (14) and a sealing flange (13) fixed on the thick wall surface (16b); the magnetic force transmission rod (20) and the push rod (19) pass through the fixed flange (10) and are fixedly connected to the force transmission flange (14); the force transmission flange (14) is arranged in the sealing flange (13); and the force transmission flange (14) and the sealing flange (13) are both connected to the fixed flange (10) by bolts (11); A sealing ring (12) is arranged between the sealing flange (13) and the fixing flange (10).

2. The conduction-cooled high-temperature superconducting electric suspension magnet structure according to claim 1, characterized in that: The thickness of the thick wall surface (16b) is greater than the thickness of the thin wall surface (16a), a sealing ring (12) is provided at the connection between the thin wall surface (16a) and the thick wall surface (16b), and the thin wall surface (16a) and the thick wall surface (16b) are connected by screws (8).

3. The conduction-cooled high-temperature superconducting electric suspension magnet structure according to claim 1, characterized in that: A plurality of the high-temperature superconducting coils (2) are connected in series with each other, and surfaces of the cold plate (1), the inner aluminum block (3) and the outer aluminum block (6) are all provided with an insulating layer.

4. The conduction-cooled high-temperature superconducting electric suspension magnet structure according to claim 1, characterized in that: An indium sheet or thermal conductive silicone grease is pasted on the contact surface between the coil box (5) and the coil cover (9) to improve the cooling effect.

5. The conduction-cooled high-temperature superconducting electric suspension magnet structure according to claim 1, characterized in that: The magnet force transmission rod (20) is connected to the coil box (5) and the force transmission flange (14) by threaded connection.

6. The conduction-cooled high-temperature superconducting electric suspension magnet structure according to claim 1, characterized in that: A plurality of cold plates (1) are also arranged on the coil cover (9), the cold plates (1) are evenly distributed, the cold plates (1) are connected to each other via a cold belt (24), the cold plates (1) are connected to a cold head of a refrigerator (21) via a cold belt (24), a cold shield (15) is arranged outside the high-temperature superconducting magnet (17), the cold shield (15) is connected to a cold head of a refrigerator (21), and the magnet force transmission rod (20) is connected to the cold plate (1) via a cold belt (24).

7. The conduction-cooled high-temperature superconducting electric suspension magnet structure according to claim 1, characterized in that: The high-temperature superconducting coil (2) is welded to a superconducting switch (29) for realizing closed-loop operation thereof, and the superconducting switch (29) is wound around an inlet end or an outlet end of the high-temperature superconducting coil (2).

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