关键词: high temperature superconducting magnet, magnetic flux conservation, field cooling method, excitation efficiency

Abstract: Gourd-shaped closed-loop high-temperature superconducting (HTS) stacked magnets are excited by the field cooling (FC) method and can operate in persistent current mode (PCM). While the FC method enables stable PCM operation, its efficiency is limited, and real-time magnetic field adjustment is challenging. According to the law of flux conservation of a superconducting closed loop, an efficient and flexible excitation method is proposed. That is, after the FC excitation process, a reverse current is passed through the excitation coil to generate a reverse magnetic flux, thereby stimulating the magnet to generate a higher magnetic field. Moreover, the magnetic field can be flexibly adjusted by changing the excitation current during the operation of the magnet. Taking the single gourd-shaped HTS plate as the research object, the feasibility of the proposed excitation method is verified through finite element simulations and experiments. The excitation effects of the two methods under the same excitation conditions are compared, and the relationship between magnetic flux density and excitation current is obtained. Results show that the proposed excitation method can stimulate the gourd-shaped HTS magnet to generate a high-intensity magnetic field, and the magnetic field of a single HTS plate is increased by 99.1% compared with that of the FC method under the same excitation conditions. Additionally, the magnetic field intensity can be flexibly adjusted as needed by changing the excitation current during operation.

Key words: high temperature superconducting magnet, magnetic flux conservation, field cooling method, excitation efficiency