Pulsed-Field Magnetization of Bulk HTS magnets in Twinned Rotor Assembly for Axial-type Rotating Machines

We study a pulsed-field magnetization of HTS bulks and application to rotating synchronous machine of axial-gap type. To increase the output performance of the rotating machine, the multiple rotor structure is designed with the alternation of the rotor with Gd-bulks and the fixed armature. Thus, we obtain a redundancy for rotor magnets operation without additional current leads nor slip rings. To assess the present redundancy, we show the result of the pulsed-field magnetization for Gd-bulks in the above mentioned multiple rotor geometry. Two Gd-bulks with 60 mm in diameter and 19 mm thick were inserted into three vortex-type Cu coils, alternatively. They are immersed into liquid nitrogen. The pulsed current was applied to three vortex-type coils as serial. The maximum applied magnetic filed was 5.7 T with the rise time of 6.6 ms. The trapped field for two Gd-bulk were 0.851 T and 0.835 T, respectively. We evidenced it is possible to perform the pulsed field magnetization for two Gd-bulks sandwiched among three armature vortex-type Cu coils, i.e., double layered rotor assembly