Speaker
Description
We are developing an advanced electric propulsion system as a promising solution to achieve carbon-neutral growth in the aviation sector. In a previous study, we successfully developed and tested a 400 kW-class fully superconducting synchronous machine using REBCO racetrack-shaped coils for both the field and armature. The cooling system utilized sub-cooled liquid nitrogen for the armature coil and helium gas for the field coil. The machine operated stably at 2,500 rpm, with a maximum line voltage and short-circuit current of 590 V and 490 A, respectively, thereby resulting in an estimated generator output of 250 kW. Building on these results, we have initiated a new project supported by the New Energy and Industrial Development Organization (NEDO) to scale up to a 2 MW-class fully superconducting synchronous generator. For the field coil, a saddle-shaped coil wound on a through-shaft was adopted to withstand high-speed rotation at 3,600 rpm. To prevent critical current degradation of the coil from bending strains during three-dimensional winding, a Face-to-Face Double Stacked REBCO tape (FFDS) was employed. For the armature coil, distributed winding using REBCO tapes was proposed to reduce AC losses and improve output performance. The armature coil wounds with 40 stacked transposed REBCO tapes to handle a large AC current of 881 Arms at 65 K. Furthermore, each REBCO tape was divided into four strands via a laser ablation technique to reduce AC loss. This presentation will provide an overview of the project and the electromagnetic design of the 2 MW superconducting synchronous generator.
