Flux-Switching Machine Based All-Electric Power Train for Future Aircraft

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Santa Cruz,
Project Term:
03/24/2021 - 09/23/2024

Critical Need:

It is estimated that flights on narrow-body aircraft are responsible for nearly half of aviation-related greenhouse gas (GHG) emissions. A decarbonized, narrow-body aircraft with electrified propulsion would provide the greatest impact on GHG emissions from a single aircraft type. ARPA-E seeks to mitigate the growing environmental burden associated with commercial air travel at minimum economic cost by developing elements of an ultra-high efficient aircraft propulsion system that uses carbon neutral liquid fuels (CNLFs). It is anticipated that the developed lightweight and high-efficiency all-electric powertrains will find direct application in the emerging urban air mobility, unmanned aircraft aerial vehicle, and select regional aircraft markets. These markets are likely to be the first adopters before the technology scales to a single-aisle aircraft.

Project Innovation + Advantages:

Power density and efficiency are crucial to electric propulsion for future aviation systems. The University of California, Santa Cruz proposes a novel all-electric power train. Each aspect of the proposed power train encompasses unique technology. The machinery relies on a flux-switching motor with high temperature superconducting field coils, which is smaller and lighter than conventional designs and has an immense advantage in terms of thermal management. The electronics are based on state-of-the-art silicon carbide-based multilevel inverter technology, which can easily interface to a medium-voltage power supply and lower electromagnetic noise and insulation stress on the motor. Preliminary designs using wide-bandgap semiconductor devices indicate that the necessary power density can be achieved. An innovative cryogenic system using solid or slushed coolant will cool stationary high-temperature superconductor field coils at 60K. Traditional air cooling will be used for the drive.

Potential Impact:

The ASCEND program has the potential to accelerate innovations and cause disruptive changes in the emerging electric aviation field.


The program will further enhance U.S. technology dominance in the field of high-performance electric motors for hybrid electric aviation. Electrified aircraft architectures can increase reliability by increasing redundancy.


An all-electric propulsion system operating on CNLF would have net-zero emissions and be much quieter for passengers and people in the vicinity of airports.


By targeting propulsion system efficiency and specific power improvements, CNLF-powered, zero-net emission aircraft will be capable of a longer range and reduced fuel cost, making them economically more attractive.


ARPA-E Program Director:
Dr. Peter de Bock
Project Contact:
Dr. Leila Parsa
Press and General Inquiries Email:
Project Contact Email:


Air Force Research Laboratory

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