Power supply and control system and method for multiple closed-loop operation superconducting coils

Abstract

The invention provides a power supply and control system and method for multiple closed-loop operation superconducting coils, and the system comprises a DC power supply which is used for providing a constant current, and meets the charging demands of the closed-loop superconducting coils; the closed-loop superconducting coil is used for generating a magnetic field, constraining plasma and supporting configuration switching of the magnetic field; the superconducting switch is connected between the power supply wire and the closed-loop connector of the closed-loop superconducting coil and is used for controlling the closed-loop and open-circuit states of the closed-loop superconducting coil and realizing switching between a charging mode and a persistent current mode; each shunt resistor is connected with one closed-loop superconducting coil in series and is used for adjusting the current of each coil when the multiple coils supply power at the same time so as to realize accurate shunt; and the current direction switch comprises a first switch S1 and a second switch S2 and is used for controlling the current direction of the closed-loop superconducting coil and supporting different magnetic field configurations. According to the invention, low-cost, efficient and accurate coil current regulation and control and flexible switching of magnetic field configuration are realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of superconducting electrical engineering, and specifically relates to a power supply and control system and method for multiple closed-loop operating superconducting coils, particularly to a charging method and current precision control technology for high-temperature or low-temperature superconducting coils, which is applied to realize flexible switching and long-time steady-state operation of the magnetic field configuration of a magnetic confinement fusion device. BACKGROUND

[0002] In addition to overcoming the loss of residual resistance of weak joints, closed-loop operating superconducting coils do not require continuous power supply, and the energy consumption is almost zero during long-term operation, greatly reducing the operating cost. In some application scenarios, such as a planar coil stellarator, multiple (such as 300) superconducting coils need to be powered and controlled. It is obvious that providing independent power supply for so many coils will greatly increase the construction cost. The following is a citation of related background technology and its problems:

[0003] Application of low-temperature superconducting coils in stellarators:

[0004] Source: Konrad Risse et al., Fabrication of the superconducting coils for Wendelstein 7-X, Nuclear Fusion, Vol. 66-68, pp. 965-969 (2003).

[0005] Content: This paper introduces the application of low-temperature superconducting materials in Wendelstein 7-X stellarators, describes the coil manufacturing and closed-loop operation technology, and proves the stability and reliability of low-temperature superconducting coils.

[0006] Problem: Although the closed-loop technology of low-temperature superconducting coils is relatively mature, the magnetic field strength generated is limited and cannot meet the needs of higher-performance flexible configuration stellarators.

[0007] Application of high-temperature superconducting materials in the field of fusion:

[0008] Source: Pierluigi Bruzzone et al., High temperature superconductors for fusion magnets, Nuclear Fusion, Vol. 58, 103001 (2018).

[0009] Content: This paper summarizes the application history and prospects of high-temperature superconducting materials (such as YBCO) in fusion devices, and points out that they can generate stronger magnetic fields, which are suitable for small-volume high magnetic field requirements.

[0010] Problem: The closed-loop junction technology for high-temperature superconducting materials is not yet fully mature, resulting in high junction resistance and critical current loss, which limits the ability to operate in a steady state for extended periods. Furthermore, high-temperature superconducting materials are expensive, requiring a trade-off between performance and cost-effectiveness.

[0011] High-temperature superconducting joint technology:

[0012] Source: Daxing Huang et al., “An efficient approach for superconducting joint of YBCO coated conductors”, Superconducting Science and Technology, Vol. 35, p. 075004 (2022).

[0013] Content: A technique for preparing YBCO high-temperature superconducting joints via a rapid chemical solution method is proposed, which significantly reduces the joint resistance and meets the requirements for closed-loop operation.

[0014] Problem: Although existing connector technology has been improved, further optimization is still needed in practical applications to ensure ultra-low resistance (< The system suffers from high current losses (<5%) and a lack of efficient integrated power supply control systems to manage large-scale coil arrays.

[0015] Experimental verification of closed-loop superconducting coils:

[0016] Source: Daxing Huang et al., “Development of a multi-pancake HTS magnet operated in persistent current mode based on superconducting joint of REBCO coated conductors”, Superconducting Science and Technology, Vol. 37, pp. 085024 (2024).

[0017] Content: The reliability of the high-temperature superconducting closed-loop coil and superconducting switch was verified through experiments, and their stability in the continuous current mode was demonstrated.

[0018] Problem: The experiments mainly focus on small-scale coil systems, and the problem of how to achieve low-cost, precise current control and configuration switching in large-scale coil arrays (such as 300 coils) has not yet been solved.

[0019] Multi-superconducting coil magnetic field experiment:

[0020] Source: D. Nash et al., "Prototyping and Test of the 'Canis' HTS Planar Coil Array for Stellarator Field Shaping", arXiv preprint repository (arXiv:2503.18960v1) (2025).

[0021] Content: The feasibility of generating complex three-dimensional magnetic fields using a multi-coil system was verified through an experiment with a 3×3 high-temperature superconducting planar coil array.

[0022] Problems: The experimental scale is relatively small, making it difficult to directly scale up to a complex stellarator system with 300 coils, and no efficient power supply and control scheme has been proposed to support precise current distribution and long-term operation of a large number of coils. Summary of the Invention

[0023] To address the above technical problems, this invention proposes a power supply and control system and method for multiple closed-loop superconducting coils. Each superconducting coil operates in a closed loop after charging, and precise control of the current of hundreds of coils can be achieved with only a few independent power supplies, greatly reducing the number of power supplies required and reducing economic costs. This invention addresses the power supply and control problems of multiple superconducting coils in flexible and variable configuration stellarators, solving the technical difficulties of high cost due to the large number of power supplies, difficulty in precise current control, insufficient stability in long-term steady-state operation, and low system integration in traditional solutions.

[0024] The technical solution of this invention is as follows:

[0025] A power supply and control system for multiple closed-loop superconducting coils includes:

[0026] DC power supply: used to provide a constant current to meet the charging requirements of the closed-loop superconducting coil;

[0027] Closed-loop superconducting coils: used to generate magnetic fields, confine plasma, and support magnetic field configuration switching;

[0028] Superconducting switch: Connected between the power supply wire and the closed-loop connector of the closed-loop superconducting coil, it is used to control the closed-loop and open-loop states of the closed-loop superconducting coil and realize the switching between charging and continuous current modes.

[0029] Shunt resistors: Each shunt resistor is connected in series with a closed-loop superconducting coil and is used when multiple coils are powered at the same time to adjust the current of each coil and achieve precise current shunting.

[0030] Current direction switch: includes two first switches S1 and two second switches S2. The two first switches S1 are respectively located at the connection point between one end of the closed-loop superconducting coil and the positive terminal of the current lead and the connection point between the other end of the closed-loop superconducting coil and the negative terminal. The two second switches S2 are respectively located at the connection point between one end of the closed-loop superconducting coil and the negative terminal of the current lead and the connection point between the other end of the closed-loop superconducting coil and the positive terminal. It is used to control the current direction of the closed-loop superconducting coil and support different magnetic field configurations.

[0031] A method for power supply and control of multiple closed-loop superconducting coils, comprising:

[0032] S110, Coil Grouping and Initialization: Based on the circumferential periodicity of the stellarator, the coils are divided into a predetermined number of groups; each group of coils is numbered, and coils with the same number in different groups are charged with the same current; the centralized control system is initialized, the target magnetic field configuration parameters are input, and the required current value for each coil is calculated;

[0033] S120, charging preparation: The central control system controls the superconducting switch to heat up, causing the superconducting switch to lose its supercharge and connect to the power supply; adjusts the shunt resistors connected in series with each coil, setting the resistance value according to the target current value; sets the current direction switch state to ensure that the coil current direction is consistent with the target magnetic field configuration;

[0034] S130, charging process: The DC power supply increases the total current at a specified rate, and the coils in the group are charged; the centralized control system dynamically adjusts the shunt resistor based on real-time feedback from the current diagnostic equipment to ensure that the current of each coil reaches the preset value.

[0035] S140, closed-loop operation: After charging is completed, the central control system controls the superconducting switch to cool down, restore the superconducting state, and form a closed-loop circuit; the power supply is disconnected from the coil, the power supply current drops to 0 at a specified rate, and the coil enters the continuous current mode.

[0036] Beneficial effects:

[0037] This invention proposes a power supply and control system for multiple closed-loop superconducting coils, addressing the power supply and precise current control issues of several to hundreds of superconducting coils (e.g., 300 superconducting coils). It solves the technical challenges of traditional solutions, such as a large number of power sources, high cost, low current regulation accuracy, insufficient long-term stability, and low system integration. Through grouped power supply, variable shunt resistors, superconducting switches, current direction control, and real-time current diagnostics, combined with a unified centralized control system, it achieves low-cost, efficient, and precise coil current regulation and flexible switching of magnetic field configuration. Attached Figure Description

[0038] Figure 1(a) is a schematic diagram of the power supply system for each superconducting coil in a power supply and control system for multiple closed-loop superconducting coils;

[0039] Figure 1(b) is a schematic diagram of a superconducting coil power supply system;

[0040] Figure 2 This is a structural diagram of a single superconducting coil;

[0041] Figure 3 This is a schematic diagram of a current direction control switch. Detailed Implementation

[0042] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0043] Figure 1(a) is a schematic diagram of the individual power supply system for the superconducting coils in a power supply and control system with multiple closed-loop superconducting coils, and Figure 1(b) is a schematic diagram of the simultaneous power supply system for the superconducting coils. The composition and structure of this system are described below with reference to Figures 1(a) and 1(b). As shown in Figures 1(a) and 1(b), the system includes a DC power supply, closed-loop superconducting coils, a superconducting switch, a shunt resistor, and a current direction switch, which are described one by one below.

[0044] DC power supply: Used to provide a constant current to meet the charging requirements of the closed-loop superconducting coils. In one embodiment, the DC power supply includes 4-8 constant current source DC power supplies, each powering a group of coils. For example, based on the circumferential periodicity and symmetry of the stellarator, 300 coils are divided into 4-8 groups, each group powered by a single power supply.

[0045] Regarding the output current of DC power supplies: If simultaneous power supply is used, the maximum output current of each power supply must be equal to or greater than the total current required by all coils in its corresponding group (for example, if each group has 75 coils and each coil requires an average of 100A, then the power supply output must be at least 75×100A=7.5kA); if individual power supply is used, the maximum output current of each power supply must be equal to or greater than the maximum current of the coils in its corresponding group.

[0046] The connection methods between the DC power supply and the coil include: each group of coils is connected in parallel to the power supply line of the corresponding power supply.

[0047] Closed-loop superconducting coil: used to generate magnetic fields, confine plasma, and support magnetic field configuration switching.

[0048] In one embodiment, the closed-loop superconducting coil is made of either a low-temperature superconducting material (such as NbTi) or a high-temperature superconducting material (such as ReBCO), depending on cost and magnetic field strength requirements.

[0049] A closed-loop superconducting coil can be a regular planar coil or an irregularly shaped three-dimensional coil. The two ends of the coil are welded together using superconducting connectors to form a closed loop; the connector resistance is lower than [missing value]. Ohms, critical current loss less than 5%, ensuring current decay of less than 0.01% within 10 hours.

[0050] Grouping and numbering: Based on the circumferential periodicity and stellarator symmetry, the coils are divided into 4-8 groups. Each group of coils is numbered according to its position. Coils with the same number in different groups are charged with the same current to ensure magnetic field consistency.

[0051] Connection method: Each coil is connected in series with a variable shunt resistor at one end, and then connected in parallel with other coils in the group to the power supply.

[0052] Superconducting switches: such as Figure 2 As shown, it is connected between the power supply wire and the closed-loop connector to control the closed-loop and open-loop states of the coil, thereby switching between charging and continuous current modes.

[0053] Structurally, superconducting switches can employ adjustable heating elements or other controllable quench devices (such as electromagnetic trigger quench devices).

[0054] The working process of the superconducting switch is as follows:

[0055] During charging: heating causes the superconducting switch to lose its supercharger state, the coil is connected to the power supply, and current flows into the coil through the power supply wire.

[0056] After charging is complete: the coil cools down to restore the superconducting state, forming a closed loop, the coil is disconnected from the power supply, and it enters the continuous current mode.

[0057] Heating temperature: Set according to the critical temperature of the superconducting material (e.g., YBCO is about 90K, NbTi is about 9K) to ensure rapid loss of superconductivity and recovery.

[0058] Response time: Switch state switching time is less than 1 second to ensure efficient charging.

[0059] Shunt resistors: Each shunt resistor is connected in series with a closed-loop superconducting coil and is used when multiple coils are powered at the same time to adjust the current of each coil and achieve precise current shunting.

[0060] The resistance range of the shunt resistor is dynamically adjusted according to the current required by the coil.

[0061] Working principle: The coils in the group are connected in parallel to the power supply, and the total current is provided by the power supply. The current is distributed according to Kirchhoff's laws by adjusting the resistance value of the series resistors of each coil.

[0062] Resistance adjustment accuracy: The resistance change step is less than 0.01 ohms, ensuring that the current control error is less than 1A.

[0063] Power withstand capability: The resistor must withstand Joule heat at maximum current (e.g., 0.01 ohms at 100A, with a power of 0.1kW).

[0064] Current direction switch: Includes two first switches S1 and two second switches S2. The two first switches S1 are respectively located at the connection point between one end of the closed-loop superconducting coil and the positive terminal of the current lead, and at the connection point between the other end of the closed-loop superconducting coil and the negative terminal. The two second switches S2 are respectively located at the connection point between one end of the closed-loop superconducting coil and the negative terminal of the current lead, and at the connection point between the other end of the closed-loop superconducting coil and the positive terminal. Figure 3 As shown, it is used to control the direction of coil current and supports different magnetic field configurations.

[0065] Working principle: The first switch S1 and the second switch S2 control the direction of current inflow and outflow, respectively. When S1 is open and S2 is closed, current flows into the coil from the end closest to the positive terminal of the current conductor and flows out from the end closest to the negative terminal of the current conductor. When S1 is closed and S2 is open, the current direction is reversed.

[0066] Switch withstand current: matched to coil current.

[0067] Switching time: less than 0.1 seconds, ensuring rapid response.

[0068] The above systems may also include current diagnostic equipment and centralized control systems, which are described in detail below:

[0069] Current diagnostic equipment, such as Figure 2 As shown, it is connected in series in the closed-loop circuit of each closed-loop superconducting coil to monitor the coil current in real time and determine whether charging is complete or recharging is required.

[0070] In one embodiment, the current diagnostic device may be a galvanometer, with each coil equipped with an independent galvanometer (such as a Hall sensor or a superconducting quantum interference device), and the measurement accuracy error is less than 1A.

[0071] Working principle: The coil current value is fed back to the centralized control system in real time to determine whether the preset current has been reached or whether the attenuation exceeds 0.01%.

[0072] Measurement frequency: at least once per minute to ensure real-time performance.

[0073] Operating environment: Adaptable to low temperature (4K-77K) or high temperature superconducting environment (77K-90K).

[0074] The centralized control system has a communication interface that connects to the power supply, superconducting switch, shunt resistor, current direction switch, and current diagnostic equipment. It is used to uniformly control all equipment and realize automated charging, replenishment, and configuration switching.

[0075] Working principle: Receives user-defined magnetic field configuration parameters and calculates the current required for each coil; controls power output, resistance adjustment, switching status, and current monitoring. Automatically executes charging, recharging, and configuration switching processes.

[0076] Control accuracy: Current regulation error is less than 1A, and configuration switching time is less than 1 hour.

[0077] Data processing capability: Supports real-time data acquisition and processing of 300 coils.

[0078] This invention also provides a method for powering and controlling multiple closed-loop superconducting coils, including the following detailed steps to ensure accurate and efficient charging of, for example, 300 coils and to achieve magnetic field configuration switching:

[0079] S110, Coil Grouping and Initialization: Based on the stellarator's circumferential periodicity (e.g., 4-8 periods), the coils are divided into a predetermined number of groups. For example, in one example, 300 coils are divided into 4-8 groups, with 37-75 coils in each group. Each group of coils is numbered, and coils with the same number in different groups are charged with the same current. The centralized control system is initialized by inputting the target magnetic field configuration parameters and calculating the required current value for each coil.

[0080] S120, charging preparation: The central control system controls the superconducting switch to heat up (e.g., to above 90K of YBCO) to cause the superconducting switch to lose supercharging and connect to the power supply; adjusts the variable shunt resistor connected in series with each coil, setting the resistance value according to the target current value; sets the current direction switch state to ensure that the coil current direction is consistent with the design direction.

[0081] S130, charging process: The DC power supply increases the total current at a specified rate (e.g., 10A / s) to charge the coils in the group; the centralized control system dynamically adjusts the shunt resistor based on real-time feedback from the current diagnostic equipment to ensure that the current of each coil reaches the preset value (error <1A).

[0082] Optionally, in step S130, the coils within the group can be charged sequentially or simultaneously through a parallel circuit; if the power output is insufficient for simultaneous charging, the coils can be charged individually sequentially or in batches (e.g., 2-3 batches per group).

[0083] S140, closed-loop operation: After charging is completed, the central control system controls the superconducting switch to cool down (e.g., to 4K-77K) to restore the superconducting state and form a closed-loop circuit; the power supply is disconnected from the coil, and the power supply current drops to 0 at a specified rate (e.g., 10A / s), and the coil enters the continuous current mode.

[0084] The method may also include the following steps:

[0085] Current monitoring and recharging steps: The current diagnostic device monitors the coil current every second. If the attenuation exceeds 0.01% or the current is lower than the target value, recharging is triggered.

[0086] The charging process includes: superconducting switch malfunctions, power is connected, shunt resistor is adjusted to charge to the target value, and closed-loop operation is restored. For coils requiring less than 1A of current, charging may be omitted to simplify operation.

[0087] Magnetic field configuration switching steps: Based on the new configuration requirements, the centralized control system recalculates the current value of each coil, adjusts the current direction switch and shunt resistor, and repeats the charging process. The switching time is controlled within 1 hour to ensure rapid response.

[0088] This invention addresses the issues of high cost, insufficient current control accuracy, inadequate long-term stability, and low system integration in the prior art for a flexible, variable-configuration stellarator superconducting coil power supply control system. The specific advantages, underlying causes, and supporting data are analyzed below.

[0089] (1) Group power supply reduces costs:

[0090] 1) Unique technical features: Utilizing the circumferential periodicity and symmetry of the stellarator, for example, 300 superconducting coils are divided into 4-8 groups, with each group powered by a DC power supply, replacing the traditional method of equipping each coil with an independent power supply.

[0091] 2) Advantages and effects:

[0092] Cost reduction: The number of power supplies is reduced from 300 to 4-8, significantly reducing equipment procurement, installation and maintenance costs.

[0093] Space optimization: Reducing the number of power sources lowers the size of the power supply system, facilitating compact device design.

[0094] Improved energy efficiency: Centralized power supply reduces energy loss during power supply operation.

[0095] 3) Causes of formation:

[0096] The circumferential periodicity (2-4 cycles) of the stellarator's magnetic field allows coils with the same number to be charged with the same current, reducing the need for independent control.

[0097] Each power supply achieves current distribution across multiple coils through parallel shunt resistors, eliminating the need for a separate power supply for each coil.

[0098] (2) Precise current shunting control improves current regulation accuracy:

[0099] 1) Unique technical features: Each superconducting coil is connected in series with a variable shunt resistor, and all coils are connected in parallel to the power supply. The current of each coil is accurately distributed by adjusting the resistance value in real time, and the error is controlled within 1A.

[0100] 2) Advantages and effects:

[0101] High-precision current control: The current of each coil can be independently adjusted to the target value to meet the requirements of complex magnetic field configurations.

[0102] Enhanced flexibility: Supports switching between various stellarator configurations without requiring hardware modifications.

[0103] Simplify control complexity: Replace independent control of multiple power supplies with resistor regulation to reduce system complexity.

[0104] 3) Causes of formation:

[0105] In parallel circuits, Kirchhoff's laws ensure that the total current is distributed proportionally to the resistance, and dynamic adjustment of the variable resistor achieves precise current shunting.

[0106] The centralized control system receives current diagnostic data in real time and automatically adjusts the resistance value to ensure that the error is minimized.

[0107] (3) The efficient power replenishment mechanism enhances long-term stability:

[0108] 1) Unique technical features: Each coil is equipped with an independent current diagnostic device (error <1A) to monitor current decay in real time (<0.01% / 10 hours) and quickly restore the target current through the same power replenishment process as charging.

[0109] 2) Advantages and effects:

[0110] Long-term steady-state operation: Ensures that the coil current decays by less than 0.01% within 10 hours, supporting long-term discharge of the stellarator.

[0111] Rapid power replenishment: The power replenishment process is efficient and does not interrupt the operation of the device.

[0112] Automated operation: The centralized control system automatically triggers power replenishment, reducing manual intervention.

[0113] 3) Causes of formation:

[0114] The resistance of the superconducting joint is extremely low ( (Ohms), combined with high-precision current diagnostics, to detect minute attenuations in a timely manner.

[0115] The power replenishment strategy reuses the charging process, using superconducting switches and shunt resistors to achieve fast and accurate power replenishment.

[0116] (4) Optimize the integration and operational efficiency of the centralized control system:

[0117] 1) Unique technical features: All equipment (power supply, superconducting switch, shunt resistor, current direction switch, current diagnostic equipment) are connected to a unified centralized control system, supporting complex magnetic field configuration switching.

[0118] 2) Advantages and effects:

[0119] High integration: A single system coordinates the charging, replenishing, and configuration switching of 300 coils, making operation simple.

[0120] Rapid configuration switching: switching time < 1 hour, supporting flexible experimental needs.

[0121] Improved reliability: Automated control reduces human error and improves system stability.

[0122] 3) Causes of formation:

[0123] The centralized control system integrates data and control logic from multiple devices and dynamically adjusts parameters based on real-time current feedback.

[0124] The modular design supports efficient management of large-scale coil arrays.

[0125] (5) Ultra-low resistance connector enhances continuous current mode:

[0126] 1) Unique technical feature: Superconducting coil junction resistance < With an ohm and critical current loss of <5%, YBCO connectors are prepared using a rapid chemical solution method to ensure high stability in closed-loop operation.

[0127] 2) Advantages and effects:

[0128] Ultra-low current decay: In continuous current mode, the decay is less than 0.01% within 10 hours, supporting long-term steady-state operation.

[0129] High reliability: Stable connector performance reduces the frequency of power replenishment and lowers operating costs.

[0130] Wide applicability: Supports both low-temperature (NbTi) and high-temperature (YBCO) superconducting materials, adapting to different design requirements.

[0131] 3) Causes of formation:

[0132] Rapid chemical solution method optimizes joint process (refer to Huang et al., 2022) to reduce resistance and critical current loss.

[0133] The closed-loop design, combined with the superconducting switch, ensures stable current after the coil is disconnected from the power supply.

[0134] Specific application examples of this invention are as follows:

[0135] Example 1: Six sets of superconducting coils in a power supply system based on high-temperature superconducting materials are powered simultaneously.

[0136] 1) System preparation and equipment:

[0137] DC power supply: 6 ABB DCS800 power supplies, 10kA, 0-100V, stability ±0.5%.

[0138] Superconducting coils: 300 YBCO coils, 30km, 4mm × 0.1mm, 200A (77K), junction resistance < ohm.

[0139] Superconducting switch: YBCO tape, heating element 50W, overrun 100K, recovery 77K, switching time <1 second.

[0140] Shunt resistor: Vishay potentiometer.

[0141] Current direction switch: TE Connectivity relay, 1500A, switching time <0.1 seconds.

[0142] Current diagnostic equipment: LEM ITZ sensor, 0-200A, error <0.5A, 10Hz.

[0143] Centralized control system: Siemens S7-1500 PLC, Modbus TCP.

[0144] Communication line: Fiber optic cable.

[0145] 2) How to use:

[0146] Initialization: Set the total output current of the power supply to 6kA, calculate the current of each superconducting coil, and evaluate the shunt resistance of each coil.

[0147] Charging preparation: Heat the superconducting switch of each superconducting coil to 100K, and select S1 or S2 to turn on according to the current direction. Figure 3 ).

[0148] Charging: Power supply from 10A / s to 6kA, sensor feedback, error <1A.

[0149] Closed loop: The superconducting switch cools down to 77K, and the power supply is disconnected.

[0150] Power replenishment is triggered when attenuation > 0.01%.

[0151] Configuration switching: Adjust the switch / resistor, time < 1 hour.

[0152] Applications: High-temperature superconducting stellarators, 20K-77K.

[0153] Example 2: Eight sets of superconducting coils in a power supply system based on low-temperature superconducting materials are powered sequentially.

[0154] 1) System preparation and equipment:

[0155] DC power supply: ordinary constant current source, 200-500A, stability ±0.2%.

[0156] Superconducting coils: 300 NbTi coils, 200A (4K), junction resistance < ohm.

[0157] Superconducting switch: NbTi wiring harness, 50W heating element, 100K quench failure, 77K recovery, switching time <0.5 seconds.

[0158] Current direction switch: CHINT relay.

[0159] Current diagnostic equipment: S LEM ITZ sensor, 0-200A, error <0.5A, 10Hz.

[0160] Centralized control system: Siemens S7-1500 PLC, Modbus TCP.

[0161] Communication line: Fiber optic cable.

[0162] 2) How to use:

[0163] Process: Each coil is powered sequentially, which takes a long time, with a current of 200-400A, a power supply of 10A / s, and an error of <1A.

[0164] Application scope: Low-temperature superconducting stellarator, 4K-20K.

[0165] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0166] Although the invention has been described with respect to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments can be conceived within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of explaining or limiting the subject matter of the invention.

Claims

1. A power supply and control system for multiple closed-loop superconducting coils, characterized in that, include: DC power supply: used to provide a constant current to meet the charging requirements of the closed-loop superconducting coil; Closed-loop superconducting coils: used to generate magnetic fields, confine plasma, and support magnetic field configuration switching; Superconducting switch: Connected between the power supply wire and the closed-loop connector of the closed-loop superconducting coil, it is used to control the closed-loop and open-loop states of the closed-loop superconducting coil and realize the switching between charging and continuous current modes. Shunt resistors: Each shunt resistor is connected in series with a closed-loop superconducting coil and is used when multiple coils are powered at the same time to adjust the current of each coil and achieve precise current shunting. Current direction switch: includes two first switches S1 and two second switches S2. The two first switches S1 are respectively located at the connection between one end of the closed-loop superconducting coil and the positive terminal of the current lead and the connection between the other end of the closed-loop superconducting coil and the negative terminal. The two second switches S2 are respectively located at the connection between one end of the closed-loop superconducting coil and the negative terminal of the current lead and the connection between the other end of the closed-loop superconducting coil and the positive terminal. It is used to control the current direction of the closed-loop superconducting coil and support different magnetic field configurations.

2. The power supply and control system for multiple closed-loop superconducting coils according to claim 1, characterized in that, The DC power supply includes 4-8 constant current source DC power supplies, each of which supplies power to a set of closed-loop superconducting coils.

3. The power supply and control system for multiple closed-loop superconducting coils according to claim 2, characterized in that, The connection method between the DC power supply and the coil includes: each group of closed-loop superconducting coils is connected in parallel to the power supply line of the corresponding power supply.

4. The power supply and control system for multiple closed-loop superconducting coils according to claim 1, characterized in that, The closed-loop superconducting coil is made of either low-temperature or high-temperature superconducting materials. The closed-loop superconducting coil is either a regular planar coil or an irregular three-dimensional coil. The two ends of the coil are welded together through superconducting joints to form a closed loop. Based on the circumferential periodicity and the symmetry of the stellarator, the coil is divided into 4-8 groups. Each group of coils is numbered according to its position. Coils with the same number in different groups are charged with the same current. Each coil is connected in series with a shunt resistor at one end and then connected in parallel with other coils in the group to the power supply.

5. The power supply and control system for multiple closed-loop superconducting coils according to claim 1, characterized in that, The superconducting switch uses an adjustable heating element or an electromagnetic trigger quench device.

6. The power supply and control system for multiple closed-loop superconducting coils according to claim 1, characterized in that, It also includes current diagnostic equipment, which is connected in series in the closed-loop circuit of each closed-loop superconducting coil to monitor the coil current in real time and determine whether charging is complete or recharging is required.

7. The power supply and control system for multiple closed-loop superconducting coils according to claim 6, characterized in that, It also includes a centralized control system with a communication interface that connects to a DC power supply, superconducting switch, shunt resistor, current direction switch, and current diagnostic equipment. This system is used to: receive user-defined magnetic field configuration parameters, calculate the current required for each coil; control power output, resistance adjustment, switch status, and current monitoring; and automatically execute charging, recharging, and configuration switching processes.

8. A method for power supply and control of multiple closed-loop superconducting coils, characterized in that, include: S110, Coil Grouping and Initialization: Based on the circumferential periodicity of the stellarator, the coils are divided into a predetermined number of groups; Number each group of coils, and charge coils with the same number in different groups with the same current; initialize the centralized control system, input the target magnetic field configuration parameters, and calculate the required current value for each coil; S120, charging preparation: The central control system controls the superconducting switch to heat up, causing the superconducting switch to lose superconductivity and connect to the power supply; adjust the shunt resistors connected in series with each coil, and set the resistance value according to the target current value; Set the current direction switch state to ensure that the coil current direction is consistent with the target magnetic field configuration; S130, charging process: The DC power supply increases the total current at a specified rate, and the coils in the group are charged; the centralized control system dynamically adjusts the shunt resistor based on real-time feedback from the current diagnostic equipment to ensure that the current of each coil reaches the preset value. S140, closed-loop operation: After charging is completed, the central control system controls the superconducting switch to cool down, restore the superconducting state, and form a closed-loop circuit; the power supply is disconnected from the coil, the power supply current drops to 0 at a specified rate, and the coil enters the continuous current mode.

9. The method for power supply and control of multiple closed-loop superconducting coils according to claim 8, characterized in that, Also includes: Current monitoring and recharging steps: The current diagnostic equipment monitors the coil current every second. If the attenuation exceeds 0.01% or the current is lower than the target value, recharging is triggered: the superconducting switch fails to quench, the power supply is connected, the shunt resistor is adjusted to charge to the target value, and the closed loop is restored.

10. The method for power supply and control of multiple closed-loop superconducting coils according to claim 8, characterized in that, Also includes: Magnetic field configuration switching steps: Based on the new configuration requirements, the centralized control system recalculates the current value of each coil, adjusts the current direction switch and shunt resistor, and repeats the charging process.

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