In many high-temperature superconducting (HTS) rotating machines, the magnetic field from one side surface of the field pole is employed as opposed to the armature winding. However, both side surfaces of the field pole can face the armature windings. Thus, we designed a double armature structure on both sides of the field poles to the HTS rotating machines.
We introduce the design and the electromagnetic study of the double armature HTS bulk synchronous machine in which the double armatures as rotors were adopted with a field pole composed of the HTS bulks for tidal current power generation.
The power and the torque density were calculated with a low speed that depends on the turbine design. A generator model consistent with the input mechanical torque of the turbine was obtained from the analysis of compatibility with the 500 kW class tidal current power generation.

 Acknowledgements
This work is supported by JSPS KAKENHI Grant Number JP16H04597.

Keywords: HTS bulk, Double armature, Synchronous machine