A high-temperature superconducting solenoid coil system and forming method for rapid current changes

Abstract

The present invention discloses a high-temperature superconducting solenoid coil system and forming method for rapid current changes, and relates to the field of high-temperature superconducting technology. A CORC conductor composed of multiple layers of YBCO superconducting tape, an outer armor, and an insulating tape form a high-temperature superconducting cable, which is tightly wrapped around a central skeleton. After the high-temperature superconducting cable wraps around the central skeleton, the outer shell is put on the outside, and together with the central skeleton, it wraps the high-temperature superconducting cable inside; the upper and lower end covers are used to connect the outer shell and the central skeleton, and the end covers are provided with holes, and the cast steel pipes are inserted into the holes of the end covers; the gap sealing glue is used to fill the gap between the end cover and the outer shell and the central skeleton, providing a sealed environment, and is used to seal the gap between the cast steel pipe and the end cover. The high-temperature superconducting solenoid coil of the present invention is formed by a set of solenoid coils of different diameters, connected by an upper flange and a lower flange, which increases the replaceability of the coil.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature superconductivity, and in particular relates to a high-temperature superconducting solenoid coil system and a forming method for rapid current changes. Background Art

[0002] Superconducting materials can be divided into low-temperature and high-temperature superconductors based on their critical temperatures. Low-temperature superconductors have been developed longer and are relatively mature, but high-temperature superconductors offer greater development potential. High-temperature superconductors typically have higher critical temperatures and critical magnetic fields. YBCO is a common copper oxide superconductor. Magnets wound with YBCO superconducting material offer high operating temperatures, low operating costs, and excellent stability.

[0003] The CORC conductor, a compact and flexible superconducting conductor developed by the National Institute of Standards and Technology (NIST) and the University of Colorado, consists of a copper core supported by an insulating outer layer, around which superconducting tape is helically wound. Its critical temperature increases with the number of winding layers. CORC conductors have a circular cross-section, are simple to manufacture, and offer high critical current density, low inductance, and low AC losses. They are often used in high-current transmission applications or magnetic coils.

[0004] High-temperature superconducting solenoid coils can be wound using either a double- or single-coil arrangement, which reduces lateral bending damage. However, gaps between the coils and the resulting coils require a large number of joints, reducing coil tightness and stability. Alternatively, a layer-wound method can be used, using a long cable to complete the winding in a single pass, reducing errors and the number of joints. The most critical aspect of layer-wound solenoid coils is the initial winding layer. Parallel winding can be used, where the initial turn of the ribbon is secured to the solenoid coil's central bobbin and then tension is applied to the coil along the central bobbin's axis. Alternatively, a lamination method can be used, where the ribbon is wound around the bobbin once, then the second turn is pressed against the first turn to prevent it from falling out, and then the winding process continues as normal. However, the initial turn of the lamination method is thicker, resulting in uneven coil thickness and potentially compromising the coil's superconductivity. Therefore, parallel winding is generally preferred.

[0005] Superconducting coils operating under conditions of rapid current fluctuations face numerous risks. Rapid current fluctuations generate a fluctuating magnetic field within the superconducting coils. The interaction between the magnetic field and the current generates significant stress within the coils. Superconducting coils subjected to long-term rapid current fluctuations may suffer material fatigue damage from repeated stress cycles, threatening their safe operation. For energy-storage superconducting magnets, excessively rapid current fluctuations can lead to excessive energy release, damaging the coil's insulation or other components. Once such a risk occurs, the superconducting coils are highly likely to quench, resulting in significant economic losses. Summary of the Invention

[0006] To address the aforementioned technical issues, the present invention provides a high-temperature superconducting solenoid coil system and molding method for rapid current fluctuations. Multiple solenoid coils of varying diameters are individually solidified and then assembled together to form a single unit. The present invention utilizes a CORC conductor made of YBCO high-temperature superconducting material for both the housing and conductor. While leveraging the advantages of high critical current and high critical magnetic field of high-temperature superconducting coils, this system improves the solenoid coil's reliability in handling rapid current fluctuations and reduces the cost of accidents.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A high-temperature superconducting solenoid coil system for rapid current changes includes a central frame, a high-temperature superconducting cable, a housing, an upper end cap, a lower end cap, an upper flange, and a lower flange. The central frame, high-temperature superconducting cable, housing, upper end cap, and lower end cap constitute a single high-temperature superconducting solenoid coil, and multiple high-temperature superconducting solenoid coils constitute a high-temperature superconducting solenoid coil system. The high-temperature superconducting cable is a CORC conductor composed of multiple layers of YBCO superconducting tape, wrapped with insulating tape and tightly wrapped around the central frame. The housing is mounted on the outside of the high-temperature superconducting cable after it wraps around the central frame. The upper end cover and the lower end cover are made of G10 material and are used to connect the outer shell and the central frame; the upper end cover and the lower end cover are both uniformly opened circumferentially for glue injection, and another hole is provided for extending the head end or the end of the high-temperature superconducting cable; each high-temperature superconducting solenoid coil is individually solidified and formed, and then a single high-temperature superconducting solenoid coil with a small diameter is inserted into a single high-temperature superconducting solenoid coil with a large diameter, and the two coils are coaxially arranged in series. Upper flanges and lower flanges are installed at both ends of the multiple high-temperature superconducting solenoid coils that have been inserted, thereby forming a high-temperature superconducting solenoid coil system including multiple layers of parallel high-temperature superconducting solenoid coils.

[0009] Furthermore, a plurality of holes are formed on the upper flange and the lower flange.

[0010] Furthermore, the holes with small diameters correspond to the holes of the upper end cap and the lower end cap of each internal coil, and there are also holes with large diameters.

[0011] Furthermore, the central skeleton, the outer shell, the upper end cover and the lower end cover form an inner cavity, and the high-temperature superconducting cable is wrapped in the inner cavity.

[0012] Furthermore, gap sealing glue is applied to the gaps formed between the upper end cover, the lower end cover, the central frame, and the outer shell respectively.

[0013] The present invention also provides a molding method for a high-temperature superconducting solenoid coil system for rapid current changes, which adopts a curing molding method to perform curing molding on a single high-temperature superconducting solenoid coil, including: inserting a casting steel pipe into the holes of the upper end cover and the lower end cover, applying a gap-sealing glue to seal; using a bottom-up and top-out casting method, allowing the curing glue to enter from the casting steel pipe of the lower end cover, flow through the inner cavity formed by the outer shell, the central skeleton, the upper end cover, and the lower end cover, immerse the high-temperature superconducting cable, and then flow out from the casting steel pipe of the upper end cover to the external environment; after the curing glue fills the inner cavity, the upper end cover and the lower end cover are clamped with an F-type clamp. , compress and fix the single high-temperature superconducting solenoid coil as a whole to ensure the stability of the single high-temperature superconducting solenoid coil during the curing process; then send the single high-temperature superconducting solenoid coil into the curing furnace for heating and baking to solidify the curing glue and complete the curing of the single high-temperature superconducting solenoid coil; finally, the single high-temperature superconducting solenoid coil with a small diameter is inserted into the single high-temperature superconducting solenoid coil with a large diameter, and the two coils are coaxially arranged in series. Upper flanges and lower flanges are installed at both ends of the multiple high-temperature superconducting solenoid coils that have been inserted, thereby forming a high-temperature superconducting solenoid coil system including multiple layers of parallel high-temperature superconducting solenoid coils.

[0014] Furthermore, the casting steel pipe is plugged into the hole of the end cover for subsequent casting of curing glue.

[0015] Furthermore, the gap between the cast steel pipe and the end cover is sealed by a gap sealing glue.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] Most existing solenoid coils have only a central skeleton and an outer shell, with multiple layers of superconducting conductors wound inside. They only need to be solidified and formed once. This design and processing is relatively simple, but once an accident occurs, the superconducting conductor inside the coil is damaged and the entire solenoid coil loses its ability to work.

[0018] The solenoid coil of the present invention is composed of multiple coils of varying diameters, each with a central framework and outer shell. This prevents the burning of one coil from affecting other coils. Once a quench occurs, the corresponding quench detection and protection systems activate, rapidly shutting off power upon detecting the quench signal and preventing further damage to the coils. Therefore, after an accident, the coils of the present invention are not completely destroyed. Only the damaged internal coil can be replaced, leaving the remaining intact coils intact, thus reducing the cost of the accident. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A partial cross-sectional view of a high-temperature superconducting solenoid coil system for rapid current changes according to the present invention;

[0020] Figure 2 This is a schematic top view of the structure of a high-temperature superconducting solenoid coil system for rapid current changes according to the present invention, with the upper flange removed;

[0021] Figure 3 Schematic diagram of the structure of a single solenoid coil of the present invention.

[0022] In the figure: 1. Upper flange; 2. Outer shell; 3. Lower flange; 4. Lower end cover; 5. High-temperature superconducting cable; 6. Center frame; 7. Upper end cover. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] like Figure 1-Figure 3 As shown, a high-temperature superconducting solenoid coil system for rapid current changes of the present invention includes an upper flange 1, a housing 2, a lower flange 3, a lower end cover 4, a high-temperature superconducting cable 5, a central frame 6, and an upper end cover 7. The housing 2, lower end cover 4, high-temperature superconducting cable 5, central frame 6, and upper end cover 7 constitute a single high-temperature superconducting solenoid coil.

[0025] Specifically, the high-temperature superconducting cable 5 is composed of a CORC conductor, external armor, and insulating tape. The CORC conductor is made of multiple layers of YBCO high-temperature superconducting tape wrapped around a hollow copper tube. The external armor isolates the tape from the curing adhesive, preventing performance degradation during curing. The insulating tape is wrapped around the external armor to further enhance insulation. The central skeleton 6 can reduce eddy current losses during coil operation. Because the CORC conductor is equipped with its own external armor, spiral grooves do not need to be machined on the central skeleton 6, reducing the difficulty of coil skeleton processing. The high-temperature superconducting cable 5 is tightly wrapped around the central skeleton 6, ensuring that there are no gaps between each layer of cable. Before wrapping, a clamp is used to secure one end of the high-temperature superconducting cable 5 to prevent the cable from falling off during the wrapping process.

[0026] After the high-temperature superconducting cable 5 is wrapped around the central frame 6, the coil formed by the high-temperature superconducting cable 5 begins to be sealed. In this embodiment, the outer shell 2 is placed over the outer surface of the high-temperature superconducting cable 5, followed by the upper end cap 7 and the lower end cap 4 at the upper and lower ends, respectively. Finally, a gap sealant is applied to the gaps between the outer shell 2, the lower end cap 4, the central frame 6, and the upper end cap 7. The upper end cap 7 and the lower end cap 4 are provided with holes.

[0027] After the sealing work, the individual high-temperature superconducting solenoid coils are cured separately. The curing molding method is as follows: the casting steel pipe is inserted into the holes of the upper end cover 7 and the lower end cover 4, and the gap sealing glue is also applied to seal. A bottom-up and top-out casting method is adopted, that is, the curing glue is allowed to enter from the casting steel pipe of the lower end cover 4, flow through the inner cavity formed by the outer shell 2, the central skeleton 6 and the upper end cover 7 and the lower end cover 4, and then flow out from the casting steel pipe of the upper end cover 7 to the external environment after immersing the high-temperature superconducting cable 5. After the curing glue fills the inner cavity, an F-type clamp is used to clamp the upper end cover 7 and the lower end cover 4, and the coil is compressed and fixed as a whole to ensure the stability of the coil during the curing process. Finally, the coil is sent to a curing furnace for heating and baking to solidify the curing glue and complete the curing of the single high-temperature superconducting solenoid coil.

[0028] The upper flange 1 and lower flange 3 are identical circular rings, with small-diameter holes on their surfaces corresponding one-to-one with the holes in the upper and lower end caps 7 and 4, reflecting the casting positions of the internal coils. The large-diameter holes are used to lead out the head and tail ends of the high-temperature superconducting cable 5 within the high-temperature superconducting solenoid coil system, facilitating subsequent connection to superconducting connectors. After all high-temperature superconducting solenoid coils are solidified, the smaller-diameter solenoid coil is nested within the larger-diameter solenoid coil, coaxially arranged in series. The upper flange 1 and lower flange 3 are installed at both ends to form a single unit, creating a multi-layer parallel solenoid coil system that generates a high-magnetic field strength. This increases the interchangeability of the coils. If a quench occurs, the impact between the individual coils is minimal; only the damaged coil needs to be replaced, reducing the cost of the accident.

[0029] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the specific examples described, or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A high-temperature superconducting solenoid coil system for rapid current changes, characterized in that: The system comprises a central frame, a high-temperature superconducting cable, an outer shell, an upper end cap, a lower end cap, an upper flange, and a lower flange. The central frame, high-temperature superconducting cable, outer shell, upper end cap, and lower end cap constitute a single high-temperature superconducting solenoid coil, and multiple high-temperature superconducting solenoid coils constitute a high-temperature superconducting solenoid coil system. The high-temperature superconducting cable is a CORC conductor made of multiple layers of YBCO superconducting tape, wrapped with insulating tape and tightly wrapped around the central frame. The outer shell is sleeved onto the outside of the high-temperature superconducting cable after the high-temperature superconducting cable wraps around the central frame. The upper and lower end caps are used to connect the outer shell and the central frame. Each high-temperature superconducting solenoid coil is individually cured and formed. Then, a single high-temperature superconducting solenoid coil with a smaller diameter is sleeved into a single high-temperature superconducting solenoid coil with a larger diameter. The coils are coaxially arranged in series. Upper and lower flanges are installed at both ends of the sleeved multiple high-temperature superconducting solenoid coils, thereby forming a high-temperature superconducting solenoid coil system comprising multiple layers of parallel high-temperature superconducting solenoid coils.

2. A high-temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: A plurality of holes are formed on the upper flange and the lower flange.

3. The high-temperature superconducting solenoid coil system for rapid current changes according to claim 2, characterized in that: The small diameter holes correspond to the holes of the upper end cover and the lower end cover of each internal coil, and there are also large diameter holes.

4. The high-temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: The central skeleton, the outer shell, the upper end cover and the lower end cover form an inner cavity, and the high-temperature superconducting cable is wrapped in the inner cavity.

5. The high-temperature superconducting solenoid coil system for rapid current changes according to claim 4, characterized in that: Use gap sealing glue to apply to the gaps formed between the upper end cover, lower end cover and the central frame and outer shell respectively.

6. The high-temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: The upper end cover and the lower end cover are made of G10 material.

7. The high-temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: The upper end cover and the lower end cover are both circumferentially and evenly opened with holes for glue injection, and another hole is provided for extending the head end or the tail end of the high-temperature superconducting cable.

8. The method for forming a high-temperature superconducting solenoid coil system for rapid current changes according to any one of claims 1 to 7, characterized in that: A single high-temperature superconducting solenoid coil is cured and formed by a curing molding method, including: inserting a casting steel pipe into the holes of the upper end cover and the lower end cover, applying a gap sealing glue to seal; using a bottom-up and top-out casting method, allowing the curing glue to enter from the casting steel pipe of the lower end cover, flow through the inner cavity formed by the outer shell, the central skeleton, the upper end cover, and the lower end cover, and then immerse the high-temperature superconducting cable and flow out from the casting steel pipe of the upper end cover to the external environment; after the curing glue fills the inner cavity, use an F-type clamp to clamp the upper end cover and the lower end cover to form a single high-temperature superconducting solenoid coil. The whole is compressed and fixed to ensure the stability of the single high-temperature superconducting solenoid coil during the curing process; then the single high-temperature superconducting solenoid coil is sent to the curing furnace for heating and baking to solidify the curing glue and complete the curing of the single high-temperature superconducting solenoid coil; finally, the single high-temperature superconducting solenoid coil with a small diameter is inserted into the single high-temperature superconducting solenoid coil with a large diameter, and the two coils are coaxially arranged in series. Upper flanges and lower flanges are installed at both ends of the multiple high-temperature superconducting solenoid coils that have been inserted, thereby forming a high-temperature superconducting solenoid coil system including multiple layers of parallel high-temperature superconducting solenoid coils.

9. The molding method according to claim 8, characterized in that: The pouring steel pipe is plugged into the hole of the end cover for pouring the subsequent curing glue.

10. The molding method according to claim 9, characterized in that: The gap between the cast steel pipe and the end cover is sealed by gap sealing glue.

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