A partially insulated high-temperature superconducting coil, a high-temperature superconducting magnet and a maglev train

Abstract

The application provides a partially insulated high-temperature superconducting coil, a high-temperature superconducting magnet and a magnetic levitation train, which comprises high-temperature superconducting tapes and an insulation layer, wherein the high-temperature superconducting tapes are used to wind coils, every n turns of the high-temperature superconducting tapes are a group of coils, adjacent high-temperature superconducting tapes in the n turns of coils in each group are not insulated, one layer of the insulation layer is arranged between the coils in each group, and the above steps are sequentially repeated until the whole coil is wound. The partially insulated high-temperature superconducting coil for the magnetic levitation train has the advantages of self-protection in case of quenching and shortened charging and discharging time, and is more suitable for superconducting high-speed magnetic levitation trains.

Description

Technical Field

[0001] This application relates to the field of superconducting electric levitation high-speed maglev transportation, especially high-temperature superconducting coils for maglev trains, which have advantages such as quench self-protection and adjustable charging time. In particular, it relates to a partially insulated high-temperature superconducting coil and a maglev train. Background Technology

[0002] In superconducting electric levitation high-speed maglev trains, superconducting magnets mounted on both sides of the vehicle interact with the long stator and levitation coils on the ground to generate traction and electro-levitation forces, thus achieving traction and levitation of the train. Compared with low-temperature superconducting materials, high-temperature superconducting materials have advantages such as lower cooling difficulty, higher critical current, and better performance under strong magnetic fields. Therefore, high-temperature superconducting coils wound with high-temperature superconducting materials have better application prospects than low-temperature superconducting coils. High-temperature superconducting coils can be divided into non-insulated high-temperature superconducting coils and insulated high-temperature superconducting coils. Non-insulated coils have advantages such as better electrothermal stability and quench self-protection, but disadvantages such as longer charging and discharging times. Insulated high-temperature superconducting coils have advantages such as shorter charging and discharging times, but disadvantages such as more difficult quench protection. Therefore, whether non-insulated or insulated coils are directly applied to high-speed maglev, there are corresponding engineering challenges.

[0003] like Figure 1 As shown, the existing magnetic levitation system includes: a vehicle body 1, a figure-eight shaped suspension coil 2, a linear synchronous motor stator coil 3, a high-temperature superconducting magnet 4, and a track 5. The high-temperature superconducting magnet 4 is located on both sides of the magnetic levitation train body 1. The strong magnetic field generated by the high-temperature superconducting magnet 4 interacts with the linear synchronous motor stator coil 3 and the suspension coil on the ground to generate traction and levitation forces, thereby achieving traction, levitation, and guidance of the train. The high-temperature superconducting magnet consists of a high-temperature superconducting coil and a low-temperature Dewar. The high-temperature superconducting coil carries a large current, thus generating a strong magnetic field. The low-temperature Dewar provides a low-temperature environment of approximately 30K for the high-temperature superconducting coil, ensuring the normal operation of the high-temperature superconducting material.

[0004] like Figure 2 As shown, the high-temperature superconducting coil is a racetrack-shaped coil wound from high-temperature superconducting tape. Figure 2 The subgraph (a) is shown in the figure.

[0005] The high-temperature superconducting tape 41 is wound in a spiral pattern on the racetrack-shaped coil 43, with the turns tightly bonded together. High-temperature superconducting coils are generally divided into insulated high-temperature superconducting coils and uninsulated high-temperature superconducting coils. Insulated high-temperature superconducting coils are wound using high-temperature superconducting tape with insulation wrapped around it, meaning that there is an insulating layer (usually a polyimide film) between the turns of the high-temperature superconducting tape. Figure 2As shown in sub-figure (b), in the insulated high-temperature superconducting coil, there is an insulating layer between adjacent high-temperature superconducting tapes, i.e., one layer of high-temperature superconducting tape 41 and one layer of insulating layer 42. In the uninsulated coil, the high-temperature superconducting tape is directly wound into a coil, and there is no insulating layer between the turns of the high-temperature superconducting tape. Figure 2 As can be seen from sub-figure (c), there is no insulating layer between adjacent high-temperature superconducting tapes of the non-insulated high-temperature superconducting coil; they are directly and tightly bonded together by the high-temperature superconducting tape 41.

[0006] Equivalent circuits of insulated and uninsulated high-temperature superconducting coils, such as Figure 3 As shown, where Figure 3 Sub-diagram (b) shows the equivalent circuit of an insulated high-temperature supercoil, in which... Figure 3 Sub-diagram (c) shows the equivalent circuit of an uninsulated high-temperature supercoil, V coil I represents the charging voltage of the coil. op I represents the charging current of the coil. s The current representing the direction of winding of the high-temperature superconducting tape (called the tangential current), I r The current representing the direction perpendicular to the winding direction of the high-temperature superconducting tape (called radial current), L coil R represents the coil inductance. s The resistance along the winding direction of the high-temperature superconducting tape (called tangential resistance), R s The reason for using a variable resistor is that the tangential resistance is related to the temperature of the coil, R. r The resistance representing the direction perpendicular to the winding of the high-temperature superconducting tape (called radial resistance) can be represented by the coil inductance L in the circuit of the high-temperature superconducting coil. coil With tangential resistance R s It is connected in series and then in parallel with the radial resistor Rr.

[0007] Figures 4-5 The charging characteristics of high-temperature superconducting coils, including the charging process of insulated coils, are as follows: Figure 4 As shown, because there is an insulating layer between adjacent high-temperature superconducting tape turns of the insulated high-temperature superconducting coil, the resistance of the insulating layer can be considered infinite. Therefore, the charging current can only flow tangentially, and the tangential current is exactly equal to the charging current. The radial current is zero. When the charging current reaches a stable value, charging is complete. The charging process of an uninsulated coil is as follows... Figure 5As shown, as the charging current increases, a large charging voltage is induced across the coil due to the coil's inductance. Since there is no insulating layer between the turns of the high-temperature superconducting tape in the uninsulated coil, the radial resistance Rr is the resistance of the metal layer between the turns. Under the influence of the charging voltage, a portion of the charging current flows through the radial resistance, thus the tangential current is less than the radial current. When the charging current stabilizes, the induced voltage across the coil gradually decreases. Because the tangential resistance of the coil (the superconducting layer resistance is almost zero) is much smaller than the radial resistance (the metal layer has resistance), the charging current gradually flows tangentially. Therefore, the tangential current gradually increases while the radial current gradually decreases. When the tangential current is almost equal to the charging current, charging is complete. Figure 5 It can be seen that the charging time of an uninsulated coil is much longer than that of an insulated coil, and similarly, the discharging time of an uninsulated coil is also much longer than that of an insulated coil.

[0008] Regarding quench protection, in uninsulated coils, when a local quench occurs, the local temperature rises sharply, causing a rapid increase in the resistance of the superconducting layer. Since there is no insulation between the turns, the current naturally flows radially through the metal layer between the turns, thus reducing the current flowing through the quench region and preventing further rapid temperature increases. The local heat gradually dissipates through heat transfer, gradually lowering the temperature of the quench region and preventing its spread. Therefore, it has quench self-protection capability and good electrothermal stability. In insulated coils, due to the insulation between the turns, the current can only flow tangentially within the high-temperature superconducting tape. When a local quench occurs, the resistance of the superconducting layer increases sharply, but the current still can only flow through the quench region, generating significant heat. This causes the temperature of the quench region to rise further, leading to further spread of the quench. Therefore, insulated coils lack quench self-protection capability and have poor electrothermal stability.

[0009] In the application scenarios of superconducting electric high-speed maglev systems, it is required that the charging and discharging time of the high-temperature superconducting coil is short, and that the superconducting coil has good electrothermal stability and quench self-protection capability. Therefore, both uninsulated and insulated coils have their own disadvantages and are difficult to be directly applied to superconducting electric high-speed maglev systems.

[0010] Patent application number 201980011273.7, entitled "Partially Insulated HTS Coil," proposes partial insulation by adding a windowed partial insulation layer between the turns. While this allows current sharing between the turns, it still doesn't solve the aforementioned problem. Patent publication number US9324486B2, entitled "Partial Insulation Superconducting Magnet," and its family of patents, "Partial Insulation Magnet with Directed Quench Energydump," both propose partial insulation technologies for superconducting magnets used in nuclear fusion, but they still cannot solve the problem. The paper "The Project Overview of the HTS Magnet for Superconducting Maglev," published in IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, Vol. 17, No. 2, describes paralleling multiple turns of high-temperature superconducting tape before inter-turn insulation, but this also fails to solve the problem. Summary of the Invention

[0011] To address the aforementioned issues, this application provides a partially insulated high-temperature superconducting coil and a magnetic levitation train.

[0012] This application provides a partially insulated high-temperature superconducting coil, comprising: a high-temperature superconducting tape and an insulating layer. The coil is wound using the high-temperature superconducting tape, with each n turns of high-temperature superconducting tape forming a group of coils. Adjacent high-temperature superconducting tapes in each group of n turns of coils are uninsulated, and an insulating layer is provided between each group of coils. This process continues until the entire coil is wound.

[0013] In some embodiments, the high-temperature superconducting tape is a high-temperature superconducting tape without insulation wrapping.

[0014] In some embodiments, the high-temperature superconducting tape is wound in a spiral manner on a racetrack-shaped reel.

[0015] In some embodiments, the turns of the high-temperature superconducting tape in each group of coils are tightly bonded together.

[0016] In some embodiments, the insulating layer is a polyimide film.

[0017] In some embodiments, the partially insulated high-temperature superconducting coil is approximately equivalent to a plurality of n-turn uninsulated coils connected in series.

[0018] In some embodiments, n turns is 10-20 turns.

[0019] In some embodiments, n turns is 14-16 turns.

[0020] This application provides a high-temperature superconducting magnet, which is composed of a partially insulated high-temperature superconducting coil as described in any of the above claims.

[0021] This application provides a magnetic levitation train, including the aforementioned high-temperature superconducting magnet, which is located on both sides of the magnetic levitation train.

[0022] The partially insulated high-temperature superconducting coil and magnetic levitation train provided in this application have the following beneficial effects:

[0023] 1. This application solves the technical problems of low electrothermal stability of superconducting coils used in superconducting electric magnetic levitation trains, difficulty in quench protection, and excessively long charging and discharging times;

[0024] 2. The partially insulated high-temperature superconducting coil proposed in this application has good quench self-protection capability, which can greatly simplify the design of quench detection and protection system, improve the robustness of the system, and facilitate engineering implementation. Attached Figure Description

[0025] The present application will be described in more detail below based on embodiments and with reference to the accompanying drawings.

[0026] Figure 1 A schematic diagram of a high-temperature superconducting electric maglev train based on existing technology;

[0027] Figure 2 Schematic diagrams of insulated and non-insulated high-temperature superconducting coils provided for existing technologies;

[0028] Figure 3 Equivalent circuit diagrams of insulated and uninsulated high-temperature superconducting coils provided for existing technologies;

[0029] Figure 4 The charging characteristics of the insulated high-temperature superconducting coil provided by the existing technology;

[0030] Figure 5 Charging characteristics of a non-insulated high-temperature superconducting coil provided as an example of existing technology;

[0031] Figure 6 This application provides a schematic diagram of a partially insulated high-temperature superconducting coil in an embodiment.

[0032] Figure 7 This application provides an approximate equivalent circuit diagram of a partially insulated high-temperature superconducting coil in its embodiments;

[0033] In the diagram, 1-vehicle body, 2-figure-eight levitation coil, 3-linear synchronous motor stator coil, 4-high temperature superconducting magnet, 41-high temperature superconducting tape, 42-insulation layer, 43-coil, 5-track.

[0034] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0037] If the application documents contain similar descriptions such as "first, second, third", the following explanation shall be added: In the following description, the terms "first, second, third" are used only to distinguish similar objects and do not represent a specific order of objects. It is understood that "first, second, third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0039] Before introducing a partially insulated high-temperature superconducting coil provided in the embodiments of this application, a brief introduction is given to the problems existing in the related technology:

[0040] In superconducting electric levitation high-speed maglev trains, superconducting magnets mounted on both sides of the vehicle interact with the long stator and levitation coils on the ground to generate traction and electro-levitation forces, thus achieving traction and levitation of the train. Compared with low-temperature superconducting materials, high-temperature superconducting materials have advantages such as lower cooling difficulty, higher critical current, and better performance under strong magnetic fields. Therefore, high-temperature superconducting coils wound with high-temperature superconducting materials have better application prospects than low-temperature superconducting coils. High-temperature superconducting coils can be divided into non-insulated high-temperature superconducting coils and insulated high-temperature superconducting coils. Non-insulated coils have advantages such as better electrothermal stability and quench self-protection, but disadvantages such as longer charging and discharging times. Insulated high-temperature superconducting coils have advantages such as shorter charging and discharging times, but disadvantages such as more difficult quench protection. Therefore, whether non-insulated or insulated coils are directly applied to high-speed maglev, there are corresponding engineering challenges.

[0041] Example 1

[0042] This application provides a partially insulated high-temperature superconducting coil. Figure 6 This application provides a schematic diagram of a partially insulated high-temperature superconducting coil; as shown in the embodiments. Figure 6 As shown, the partially insulated high-temperature superconducting tape includes: a high-temperature superconducting tape 41 and an insulating layer 42. Coils are wound using the high-temperature superconducting tape 41, with each n turns of high-temperature superconducting tape forming a group of coils. Adjacent high-temperature superconducting tape turns in each group of n turns are uninsulated, and an insulating layer is placed between each group of coils. This process continues until the entire coil is wound. The high-temperature superconducting tape is an uninsulated high-temperature superconducting tape. The high-temperature superconducting tape is wound in a spiral pattern on a racetrack-shaped coil. The turns of the high-temperature superconducting tape in each group of coils are tightly bonded together. The insulating layer is a polyimide film. The partially insulated high-temperature superconducting coil is approximately equivalent to multiple uninsulated coils with n turns connected in series. Through model building and analysis, it was found that when the number of n turns is too large, the charging time is long, failing to solve the problems mentioned in the background technology. When the number of n turns is too small, the quench self-protection capability is poor, and the electrothermal stability is also poor. After extensive experiments and trial production verification, it was found that 10-20 turns is optimal, which can reduce the charging time by more than 30% compared to an uninsulated coil of the same size. More preferably, the number of n turns is 14-16 turns, which can reduce the charging time by more than 40% compared to an uninsulated coil of the same size, and also has excellent quench self-protection capability and electrothermal stability.

[0043] This application is ingenious, simple, easy to process, and economical. Most importantly, it combines the advantages of both insulated and non-insulated coils, which shortens the charging and discharging time while also having excellent quench self-protection capability and electrothermal stability.

[0044] The partially insulated high-temperature superconducting coil proposed in this embodiment can ensure that the coil has good quench self-protection capability and also has a short charging and discharging time, which is very beneficial to the application of high-temperature superconducting coils in electric levitation high-speed maglev systems.

[0045] The partially insulated high-temperature superconducting coil proposed in this embodiment can have its charging and discharging time adjusted according to design requirements, which is beneficial for optimizing high-temperature superconducting magnets for different application scenarios.

[0046] The partially insulated high-temperature superconducting coil proposed in this embodiment has good quench self-protection capability, which can greatly simplify the design of quench detection and protection system, improve the robustness of the system, and facilitate engineering implementation.

[0047] Example 2

[0048] Based on the foregoing embodiments, the partially insulated high-temperature superconducting coil proposed in this embodiment balances shortened charging and discharging time with quench self-protection capability, making it better suited for high-speed maglev applications. The partially insulated high-temperature superconducting coil proposed in this embodiment is as follows: Figure 6 As shown, high-temperature superconducting tape without insulation is wound in a spiral pattern on a racetrack-shaped coil. Adjacent n turns of the high-temperature superconducting tape are wound without insulation, meaning there is no insulating layer in these n turns; the superconducting tape is directly and tightly bonded together. However, after winding all n turns without insulation, an insulating layer is added, and this process is repeated until the entire coil is wound. A cross-sectional diagram is shown below. Figure 6 As shown in sub-figure (b), the n-turn superconducting tape layer and the insulating layer are arranged sequentially. The partially insulated high-temperature superconducting coil is approximately equivalent to multiple n-turn uninsulated coils connected in series.

[0049] Figure 7 The partially insulated high-temperature superconducting coil provided in this application provides an approximate equivalent circuit diagram. The charging and discharging time of the uninsulated coil decreases as the number of turns decreases because the number of turns in each uninsulated portion (adjacent n turns) is much smaller than the total number of turns in the coil. Therefore, the charging and discharging time of the partially uninsulated coil is much shorter than that of the uninsulated coil. When n equals 1, the partially insulated coil becomes an insulated coil; when n equals the total number of turns, the partially insulated coil becomes an uninsulated coil. Therefore, the smaller n is, the shorter the charging and discharging time; the larger n is, the longer the charging and discharging time. The charging and discharging time can be adjusted by adjusting the value of n.

[0050] In this embodiment, regarding quench protection, in a partially insulated high-temperature superconducting coil, when a local quench occurs, the local temperature rises sharply, causing a rapid increase in the resistance of the superconducting layer. Since there is no insulating layer between each n turns of the high-temperature superconducting tape, the current naturally flows radially through the metal layer between the turns, thereby reducing the current passing through the quench region and preventing the temperature from rising further rapidly. The local heat gradually dissipates through heat transfer, thus gradually reducing the temperature of the quench region and preventing the quench from spreading. Therefore, it has quench self-protection capability and good electrothermal stability. When the value of n is small, the quench self-protection capability is poor; the larger the value of n, the stronger the quench self-protection capability.

[0051] Analysis through model building revealed that when the number of n turns is too large, the charging time is too long, failing to solve the problems mentioned in the background technology. When the number of n turns is too small, the quench self-protection capability is poor, and the electrothermal stability is also poor. After extensive experiments and trial production verification, it was found that 10-20 turns is optimal, which can reduce the charging time by more than 30% compared to an uninsulated coil of the same size. More preferably, 14-16 turns is optimal, which can reduce the charging time by more than 40% compared to an uninsulated coil of the same size, and also has excellent quench self-protection capability and electrothermal stability.

[0052] This embodiment can solve the technical problems of low electrothermal stability of superconducting coils used in superconducting electric magnetic levitation trains, difficulty in quench protection, and excessively long charging and discharging times. At the same time, the partially insulated high-temperature superconducting coil proposed in this embodiment has good quench self-protection capability, which can greatly simplify the design of quench detection and protection system, improve the robustness of the system, and facilitate engineering implementation.

[0053] Example 3

[0054] Based on the foregoing embodiments, the high-temperature superconducting magnet is composed of the partially insulated high-temperature superconducting coils described in Embodiments 1-2.

[0055] Example 4

[0056] Based on the foregoing embodiments, this application provides a magnetic levitation train, including the high-temperature superconducting magnet described in Embodiment 3, wherein the high-temperature superconducting magnet is located on both sides of the magnetic levitation train.

[0057] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0058] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0059] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0060] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units. They may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs.

[0061] In addition, each functional unit in the various embodiments of this application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0062] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A partially insulated high-temperature superconducting coil, characterized in that, It includes a high-temperature superconducting tape and an insulating layer. The high-temperature superconducting tape is used to wind the coil. Every n turns of high-temperature superconducting tape is a group of coils. The adjacent high-temperature superconducting tapes in each group of n turns of coils are not insulated. An insulating layer is set between each group of coils. This process is repeated until the entire coil is wound. The high-temperature superconducting tape is a high-temperature superconducting tape without wrapping insulation; The turns of the high-temperature superconducting tape in each group of coils are tightly bonded together; The smaller n is, the shorter the charging and discharging time; the larger n is, the longer the charging and discharging time. In terms of quench protection, in the partially insulated high-temperature superconducting coil, when a quench occurs locally, the local temperature rises, causing the resistance of the superconducting layer to increase. Since there is no insulation between each n turns of high-temperature superconducting tape, the current naturally flows radially through the metal layer between the turns, thereby reducing the current through the quench region and preventing the temperature from rising further. The larger n is, the stronger the quench self-protection capability. The partially insulated high-temperature superconducting coil is approximately equivalent to multiple n-turn uninsulated coils connected in series; The number of turns n is 10-20 turns.

2. The partially insulated high-temperature superconducting coil according to claim 1, characterized in that, The high-temperature superconducting tape is wound in a spiral shape on a racetrack-shaped reel.

3. The partially insulated high-temperature superconducting coil according to claim 1, characterized in that, The insulating layer is a polyimide film.

4. The partially insulated high-temperature superconducting coil according to claim 1, characterized in that, The number of turns n is 14-16 turns.

5. A high-temperature superconducting magnet, characterized in that, The high-temperature superconducting magnet is composed of a partially insulated high-temperature superconducting coil as described in any one of claims 1 to 4.

6. A magnetic levitation train, characterized in that, Includes the high-temperature superconducting magnet as described in claim 5, wherein the high-temperature superconducting magnet is located on both sides of the magnetic levitation train.

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