Since bulk magnets can easily generate magnetic fields of 2 tesla or higher, they are being considered for applications such as generators for large wind turbines and electric propulsion systems for aircraft and large ships. Pulsed-field magnetization (PFM) is a practical method for industrial applications because it can magnetize a bulk in any location using general-purpose equipment. On the other hand, since the performance of the bulk is not fully demonstrated in terms of the trapped field, it is necessary to improve the amplitude of trapped field and to simplify magnetization process. In previous studies, it has been found that magnetic flux penetrates from areas with low characteristics and is trapped in areas with high characteristics. However, since recent improvements in bulk fabrication methods have improved the uniformity of the bulk, the trapped field becomes larger if the magnetic flux can penetrate, but strong magnetic shielding makes it difficult for the magnetic flux to penetrate into the bulk. We have focused on the shape of the soft-iron yoke used in PFM and have examined the possibility of improving the magnetization efficiency by changing the shape of the yoke. Originally, our aim was to reduce the weight of equipment by reducing the amount of soft-iron, but we understood that changing the shape of the yoke distorts the applied field distribution, which may affect the magnetic-flux trapping characteristics. This paper investigates numerically how the applied field changes by changing the shape of the soft-iron yoke and how the applied field distribution affects the trapped field characteristics.

This work was supported by JSPS KAKENHI Grant Number 24K07458.

Keywords: REBCO bulk, pulsed-field magnetization, soft-iron yoke, applied field