Modeling and characteristics investigation of self-regulating HTS flux pump

High-temperature superconducting (HTS) magnets are promising in the application of high-intensity magnetic field. HTS flux pumps are devices that can charge closed HTS magnets without direct electrical contact. Simulation is an effective way to clarify the physical mechanism and provide further insight into the design of the device. In this work, we propose an accurate and efficient modeling methodology to simulate the transformer-rectifier HTS flux pump, which has considered electromagnetic and thermal coupling. The validity of the model has been verified by experimental results and theoretical calculations. The working characteristics of the HTS flux pump are investigated based on the proposed model, including DC bias component in the charging loop, the voltage recovery delay of the dynamic bridge and the temperature distribution in the dynamic bridge. The simulation results clearly depict working details of the device, in terms of electricity, magnetism and heat. The proposed model can serve as a powerful tool to design the HTS flux pump in practical applications.

Section: Introductionmentioning

confidence: 99%

Modeling methodology for the transformer-rectifier flux pump considering electromagnetic and thermal coupling

Li,

Xin

et al. 2023

“…Recent numerical modelling work utilizing an effectivecircuit (or 'lumped parameters') methodology has been limited to exploring the influence of sub-components of the FP, such as the bridge [18] or the transformer [19]. Combining these subsystems into the same model has only just been reported by Zhai et al [20] with some explanatory success for an air-core transformer self-rectifier. What such modelling should enable however is; (i) quantitative performance prediction to facilitate model validation, and (ii) an understanding of the interplay between all subcomponents of the FP such as the input waveform, transformer and circuit impedances.…”

Section: Introductionmentioning

confidence: 99%

Effective circuit modelling and experimental realization of an ultra-compact self-rectifier flux pump

Mallett

Venuturumilli

Geng

et al. 2023

This paper presents experimental and modelling results of an ultra-compact self-rectifier flux pump energizing a superconducting coil. The device fits inside a volume of 65x65x50 mm and generates up to 320 A dc through the coil and a peak output voltage up to 60 mV. We also develop and present a full electromagnetic effective circuit model of the flux pump and compare its predictions to the experimental results. We show that our model can reproduce accurately the charging of the load coil and that it reproduces the systematic dependence of the maximum load coil current on the input current waveform. The experiments and modelling together show also the importance of dc-flux offsets in the transformer core on the final achievable current through the coil. The miniaturization possible for this class of flux pump and their minimal heat-leak into the cryogenic environment from thermal conduction make them attractive for applications with demanding size, weight and power limitations. Our effective circuit model is a useful tool in the understanding, design and optimization of such flux pumps which will accelerate their progression from research devices to their application.

“…Various developments in HTS flux pumps have been reported recently. These flux pumps include traveling magnetic field-induced flux pumps (dynamo, linear flux pumps) [22,24,[43][44][45] and HTS rectifier flux pumps (thermally switching, dynamic resistance switching, JcB switching, and selfswitching) [26][27][28][46][47][48]. HTS flux pumps can charge the magnet and compensate for any current decay, enabling the quasi-persistent operation of HTS-CC magnets.…”

Section: Introductionmentioning

confidence: 99%

Feedback-controlled flux modulation for high-temperature superconducting magnets in persistent current mode

Iftikhar

Zhang²,

Yuan³

2023

High-temperature superconducting (HTS) magnets have found wide applications in high-field settings owing to their high current capabilities. Typically, these magnets are powered by high-current power supplies via current leads, which can complicate insulation between cryogenic and room temperature environments. However, new developments in flux pumps for HTS magnets have enabled charging of kA levels of current without power supplies. By combining flux pumps with HTS persistent current operation, it is possible to achieve accurate flux modulation and eliminate the need for power supplies and current leads. In this study, we report on a novel feedback-controlled flux modulation for HTS magnets in persistent current operations. This flux modulation is based on a flux pump mechanism that generates a DC voltage across the charging superconductor by applying a current higher than its critical current. With closed-loop feedback control, our flux modulation can achieve precise injection and reduction of HTS magnet current in increments of 0.5 A. This technology can lead to stable magnetic fields in HTS magnet designs. We anticipate that this work will enable future magnets to operate in a stable persistent current mode within a closed cryogenic chamber, significantly reducing the footprint and power demand of HTS magnets and opening up new opportunities for their applications.