A direct current conversion device for closed HTS coil of superconducting magnetic energy storage

High-temperature superconducting (HTS) magnets are widely used in various fields because of their superior performance. However, the dc operating current of a closed HTS coil, after energization, cannot be adjusted flexibly and efficiently, which limits the application scenarios of HTS magnets. Besides, the joint resistance within HTS magnets will cause obvious decay of operating current, which seriously impacts the performance. In this work, a novel dc conversion device using variable superconducting inductor is proposed, which can effectively step up and step down the dc operating current of closed HTS coils. An experimental prototype was designed and built. Experimental results show the proposed dc conversion device can tune the operating current of the closed HTS coil in a wide range with little power loss. Simulation tests are carried out to explore further working details and application potential of the proposed device. Apart from adjusting the operating current, the proposed dc conversion device could also serve to compensate field decay of the HTS magnets caused by joint resistance or external field.

Automated summary

In this study, a novel dc conversion device using variable superconducting inductor is proposed to adjust the operating current of closed HTS coils flexibly and efficiently. Experimental results demonstrate that the proposed device can tune the current in a wide range with little power loss. Simulation tests further explore the working details and application potential. Besides adjusting the current, the device can also compensate field decay of the HTS magnets caused by joint resistance or external field.