Conceptual Design of a Superconducting Aero Electric Engine System

The goal of the development of an electric aircraft engine is to create an aircraft system that achieves ultimate efficiency using hydrogen fuel instead of fossil fuels. Therefore, it is necessary to focus on reducing weight as much as possible, and this paper describes the approach to such fuel cell-powered aircraft. The authors have adopted a superconducting coreless rotating electric machine with an integrated hydrogen tank and are pursuing a target of 70kg or less for the main components of a 2MW rotating electric machine. High-temperature superconducting wires have zero electrical resistance and can carry a very high current density, but the alternating current (AC) loss generated when used in AC has been an issue in their application to rotating electric machines. In 2023, The SCSC cable was developed to be a low-AC-loss, robust, and high current cable concept, in which copper-plated multifilament coated conductors are wound spirally on a core. In addition to using this superconducting cable, the structure is designed to minimize the weight required to maintain the cryogenic state, and it consists of a single structure that combines a hydrogen tank and a rotating electric motor. This new type of superconducting rotating machine combines flux concentrated type field rotor technology and canned motor technology and provides a seal structure and bearings that make it practical. To put superconducting rotating machines to practical use in electric aircraft engines, it is necessary to transmit high currents from fuel cells, and this system proposes a flexible superconducting cable for power transmission with a hydrogen supply function that combines light weight and flexibility. As a result of performance estimation, we have confirmed that this superconducting rotating machine has the potential to improve performance by more than 10 times compared to our conventional products.