磁通泵用高温超导变压器电流输出特性的等效电路建模与实验研究

doi:10.19595/j.cnki.1000-6753.tces.250892

Abstract
Figure/Table
References
Related Citation (15)

Download: PDF (2558 KB) HTML (1 KB)
Export: BibTeX | EndNote (RIS)

Abstract As a low-voltage, high-current DC power supply device, the superconducting flux pump charges superconducting loads through contactless power transfer, offering significant advantages such as compact structure, low heat leakage, and high output current. It holds important application value in fields like magnetic resonance imaging (MRI), high-field magnet facilities, superconducting magnetic energy storage, and superconducting maglev. The transformer-rectifier type flux pump utilizes a superconducting switch to rectify the transformer’s AC current into DC, featuring benefits such as high charging voltage and flexible control over the charging process. Within a transformer-rectifier flux pump, the superconducting transformer plays a critical role. In typical designs, to achieve a high current amplification ratio, the primary winding turns are usually increased while the secondary winding is correspondingly reduced to a single-turn structure. This configuration leads to a significantly large primary self-inductance and an extremely small secondary self-inductance. Simultaneously, due to the very low resistance of the superconducting secondary, the reactive component dominates the secondary impedance, making the transformer current highly sensitive to changes in secondary inductance. Accurately obtaining the inductance parameters thus becomes key to precisely calculating the transformer’s current output and the flux pump’s charging performance. However, existing methods typically calculate parameters like transformer reluctance or inductance based on theoretical formulas, which struggle to accurately characterize the nonlinear permeability of the core and leakage flux effects, limiting computational accuracy. Furthermore, the circuit models commonly employed are mostly based on solving transient differential equations, leading to low computational efficiency when simulating the slow charging of large inductive loads, which hampers the timeliness of system optimization design.
To address the aforementioned issues, this paper focuses on the current output characteristics of high-temperature superconducting (HTS) transformers used in flux pumps. Firstly, the transformer’s inductance parameters are determined experimentally, its equivalent circuit model is established, and its short-circuit characteristics are analyzed. Building upon this, an equivalent circuit model for the flux pump system is further constructed, and an HTS transformer with high output current capability is designed. Subsequently, the charging performance of the flux pump system for a superconducting electrodynamic suspension (EDS) magnet is investigated.
The main conclusions are as follows:
(1) Transformer short-circuit experiments show that as the primary voltage U₁ increases, the short-circuit current variation can be divided into four stages: linear increase, nonlinear increase, nonlinear decrease, and sudden drop. These nonlinear changes originate from the increase in the resistance of the superconducting secondary winding.
(2) Regarding the two equivalent circuit models of the transformer: the frequency-domain model can effectively predict the linear increase stage of the short-circuit current (when the peak secondary current is below its critical current); the time-domain model can accurately predict both the linear and nonlinear increase stages of the short-circuit current (when the peak secondary current exceeds its critical current but does not cause significant temperature rise).
(3) By introducing the load charging curve equation into the frequency-domain model, the proposed model can quickly and fairly accurately reproduce the charging process of the flux pump. Compared with the time-domain model, its maximum relative error is 7.4%, but the computational efficiency is improved by three orders of magnitude, providing an efficient computational tool for transformer optimization design and flux pump charging performance analysis.
(4) To improve the current output capability of the HTS transformer, a superconducting transformer based on a parallel secondary structure was designed. The flux pump system using this transformer can excite an HTS EDS magnet to its rated current of 250 A, but the required excitation time is as long as 30 hours, necessitating further optimization to shorten the excitation time.

Key words： High-temperature superconducting(HTS) magnets flux pumps transformers equivalent circuit superconducting electrodynamic suspension (EDS)

Received: 26 May 2025

PACS:

TM26

	Service

	E-mail this article
	Add to my bookshelf
	Add to citation manager
	E-mail Alert
	RSS
	Articles by authors
	Gong Tianyong
	Loï
	c Qué
	val
	Ma Guangtong

Cite this article:

Gong Tianyong,Loï,c Qué等. Equivalent Circuit Modeling and Experimental Study on Current Output Characteristics of High-Temperature Superconducting Transformers for Flux Pumps[J]. Transactions of China Electrotechnical Society, 2026, 41(13): 4515-4526.

URL:

https://dgjsxb.ces-transaction.com/EN/10.19595/j.cnki.1000-6753.tces.250892 OR https://dgjsxb.ces-transaction.com/EN/Y2026/V41/I13/4515

[1] 翟雨佳, 刘欣怡, 汪沨, 等. 高温超导磁通泵研究进展与发展趋势[J]. 电工电能新技术, 2021, 40(11): 37-45.
Zhai Yujia, Liu Xinyi, Wang Feng, et al.Research progress and development trend of high temperature superconducting flux pump technology[J]. Advanced Technology of Electrical Engineering and Energy, 2021, 40(11): 37-45.
[2] Wang Wei, Wei Jiafu, Yang Chao, et al.Review of high temperature superconducting flux pumps[J]. Superconductivity, 2022, 3: 100022.
[3] Geng Jianzhao, Lin Yi, Bumby C W, et al.High-T_c superconducting transformer-rectifiers: principle, realization, and applications[J]. Superconductor Science and Technology, 2025, 38(4): 043001.
[4] Gong Tianyong, Quéval L.Impact of switch overcritical regime on the output voltage and charging current in an AC field-controlled transformer-rectifier HTS flux pump[J]. Superconductor Science and Technology, 2025, 38(4): 045001.
[5] 翟耀, 马光同, 刘力豪, 等. 自驱式高温超导磁通泵的跨壁励磁实验与粒子群优化研究[J]. 电工技术学报, 2025, 40(18): 5759-5775.
Zhai Yao, Ma Guangtong, Liu Lihao, et al.Through-wall charging experiment and particle swarm optimization design of self-regulating high temperature superconducting flux pump[J]. Transactions of China Electrotechnical Society, 2025, 40(18): 5759-5775.
[6] Lin Yi, Hu Changhao, Yang Zaixing, et al.A full-wave high-T_c superconducting transformer-rectifier flux pump activated with two electromagnets[J]. Superconductor Science and Technology, 2025, 38(4): 045007.
[7] Zhang Heng, Geng Jianzhao, Coombs T A.Magnetizing high-T_c superconducting coated conductor stacks using a transformer-rectifier flux pumping method[J]. Superconductor Science and Technology, 2018, 31(10): 105007.
[8] Geng Jianzhao, Badcock R A, Bumby C W.A wireless rectifier for inductively energizing high direct-current high-temperature superconducting magnets[J]. IEEE Transactions on Industrial Electronics, 2021, 68(4): 3273-3281.
[9] Geng Jianzhao, Bumby C W, Badcock R A.Maximising the current output from a self-switching kA-class rectifier flux pump[J]. Superconductor Science and Technology, 2020, 33(4): 045005.
[10] 马韬, 朱志芹, 邱清泉, 等. 1250kV·A三相高温超导变压器的系统集成与试验[J]. 电工技术学报, 2016, 31(21): 188-195.
Ma Tao, Zhu Zhiqin, Qiu Qingquan, et al.Integration and tests of the 1250 kV·A three-phase high temperature superconducting transformer[J]. Transactions of China Electrotechnical Society, 2016, 31(21): 188-195.
[11] Geng Jianzhao, Matsuda K, Fu Lin, et al.Operational research on a high-T_c rectifier-type superconducting flux pump[J]. Superconductor Science and Technology, 2016, 29(3): 035015.
[12] Geng Jianzhao, Painter T, Long P, et al.A kilo-ampere level HTS flux pump[J]. Superconductor Science and Technology, 2019, 32(7): 074004.
[13] Geng Jianzhao, Wang Bin, Baghdadi M, et al.Feedback control of a rectifier type HTS flux pump: stabilizing load current with minimized losses[J]. IEEE Transactions on Applied Superconductivity, 2017, 27(4): 0500104.
[14] Iftikhar M, Zhang Min, Yuan Weijia.Feedback-controlled flux modulation for high-temperature superconducting magnets in persistent current mode[J]. Superconductor Science and Technology, 2023, 36(5): 055008.
[15] Yao Hongtai, Lin Yi, Zhou Miaoyan, et al.An integrated controller for compact rectifier-type HTS flux pumps[J]. IEEE Transactions on Applied Superconductivity, 2023, 33(8): 4501006.
[16] Mallett B P P, Venuturumilli S, Geng J, et al. Effective circuit modelling and experimental realization of an ultra-compact self-rectifier flux pump[J]. Superconductor Science and Technology, 2023, 36(6): 065005.
[17] Rice J H P, Mallett B P P, Moseley D A, et al. A full-wave HTS flux pump using a feedback control system[J]. Superconductivity, 2023, 8: 100064.
[18] Francis A C, Venuturumilli S, Moseley D A, et al.Electrical, magnetic and thermal circuit modelling of a superconducting half-wave transformer rectifier flux pump using Simulink[J]. Superconductivity, 2023, 7: 100053.
[19] Francis A C, Moseley D A, Clarke J, et al.J_c (B) transformer rectifier flux pump optimisation via simulation[J]. Superconductor Science and Technology, 2024, 37(12): 125005.
[20] Li Chao, Wang Shengjie, Jia Hanru, et al.Impacts of the saturated transformer on the HTS flux pump[J]. IEEE Transactions on Applied Superconductivity, 2021, 31(8): 5500504.
[21] Rice J H P, Moseley D A, Petrov A, et al. Current-sharing behaviour of single-phase HTS transformers with stacked-tape cables[J]. IEEE Transactions on Applied Superconductivity, 2024, 34(3): 5500105.
[22] Geng Jianzhao, Coombs T A.Modeling methodology for a HTS flux pump using a 2D H-formulation[J]. Super-conductor Science and Technology, 2018, 31(12): 125015.
[23] Li Chao, Li Gengyao, Xin Ying, et al.Modeling methodology for the transformer-rectifier flux pump considering electromagnetic and thermal coupling[J]. Superconductor Science and Technology, 2024, 37(1): 015002.
[24] Gong Tianyong, Quéval L.A field-controlled high-temperature superconducting switch: experiment and simulation[J]. IEEE Transactions on Applied Supercon-ductivity, 2025, 35(5): 5000305.
[25] Casali M.Experimental analysis and numerical simulation of quench in superconducting HTS tapes and coils[D]. Bologna: University of Bologna, 2014, p.113.
[26] 宋萌, 周羽生, 唐跃进, 等. 电磁发射用高温超导空心脉冲变压器[J]. 电工技术学报, 2007, 22(12): 72-76.
Song Meng, Zhou Yusheng, Tang Yuejin, et al.HTS air-core pulse transformer for electromagnetic launch[J]. Transactions of China Electrotechnical Society, 2007, 22(12): 72-76.
[27] COMSOL Multiphysics. Finite-element software package[OL]. http://www.comsol.com.
[28] 李晓松, 陈乔夫, 龙谷宗, 等. 超导变压器几种不同绕组形式的环流分析[J]. 电工技术学报, 2005, 20(7): 28-33.
Li Xiaosong, Chen Qiaofu, Long Guzong, et al.Study of circulating current distributions for different types of HTS transformer windings[J]. Transactions of China Electrotechnical Society, 2005, 20(7): 28-33.
[29] Ma Guangtong, Gong Tianyong, Wang Ruichen, et al.Design, fabrication and testing of a coated conductor magnet for electrodynamic suspension[J]. Superconductor Science and Technology, 2022, 35(2): 025013.
[30] Gong Tianyong, Ma Guangtong, Quéval L.An accurate and efficient 3D steady-state model for simulating the voltage-current characteristics of HTS coils[J]. Superconductor Science and Technology, 2025, 38(10): 105011.