Power converters are essential components in electrified aircraft systems as they help manage electrical energy by converting power from one form to another, including alternating current (AC) to direct current (DC) power or vice versa.
Overview
NASA is sponsoring efforts to research and develop advanced power converter technologies for future electrified aircraft. They would be larger, lighter, and more efficient, with power densities that are 2-3 times greater compared to the state-of-the-art converters on today’s aircraft in the megawatt (MW)-class or larger.
Research conducted by the agency will pave the way for achieving the performance, functions, and safety needed for large electric and hybrid electric aircraft.
NASA Innovations
Researchers at NASA Glenn have designed a variety of converters that can be used on different electrified aircraft configurations and offer improvements in vehicle performance and efficiency.
Generalized Intelligent Motor Control (GIMC) Hybrid Electric Integrated System Testbed (HEIST)
2016-2017
The GIMC-HEIST was designed to produce 11 kilowatts (kW) of power while taking in a 400-voltage direct current (VDC) bus that carries direct current to various system components. Developed to support testing of electrified aircraft propulsion at NASA’s Armstrong Flight Research Center in Edwards, California, this converter was the first time researchers at NASA Glenn used silicone carbide (SiC) MOSFETs, or metal-oxide-semiconductor-field-effect-transistors in the system design, which allowed them to achieve significantly higher efficiency motor converters through fast switching capabilities. This technology supported NASA’s Advanced Air Transport Technology (AATT) project enabling fixed-wing transport aircraft.
High Lift Motor Controller (HLMC)
2018-2023
The HLMC was designed to spin the smaller motors that made up the distributed electric propulsion (DEP) system of NASA’s first all-electric X-57 experimental aircraft. This converter produced a maximum power of 14-kW output while taking in a 538-VDC bus and weighing only 1 kg, with a peak efficiency of 98.3%. The system operated with a microcontroller-based control and used only passive air cooling from the propeller wash, which is the airflow generated around the propeller when operating, instead of the more traditional fluid cooling loops that would have added unacceptable weight. The HLMC completed all pre-flight acceptance tests for both hardware and software.
High-Efficiency Electric Aircraft Thermal Research (HEATheR) Converter
2019-2021
The HEATheR converter was a two-year effort under NASA’s Convergent Aeronautics Solutions (CAS) program, intended to promote short-term aeronautics research efforts. This converter was designed for a 72-kW power output at a 538-VDC input, a significant power jump from the HLMC, with a slight bump in efficiency up to 98.6%. The HEATheR converter featured commercial off-the-shelf (COTS) Field Programmable Gate Arrays (FPGA) based control and a more complicated architecture using multi-level and interleaving topologies for a MOSFET configuration.
Cruise Motor Controller (CMC)
2020-2023
The CMC was designed for the higher power cruise motors on NASA’s X-57 aircraft. This converter produced a 36-kW power output at a 538-VDC input, with over 97% efficiency. Similar to the HLMC, this converter also featured passive air cooling and completed pre-flight acceptance testing.
Advanced Power Electronics Group 250 kW Converter
2021-Present
Developed for NASA’s Advanced Air Transport Technology (AATT) project, this converter features another significant jump in power up to 250 kW with a 1,000-VDC bus. Rated for an altitude of 40,000 feet and boasting an efficiency of 99.3% and a specific power of 10.6 kW/kg, this converter features the greatest advancement in all aspects of electrical and mechanical design to date. The system incorporates the multi-level and interleaved MOSFET topology of the HEATheR converter and introduces custom FPGA control.
Motor And Generator Intelligent Converter (MAGIC)
2022-Present
MAGIC was developed under NASA’s Convergent Aeronautics Solutions (CAS) program, supporting the SUbsonic Single Aft eNgine (SUSAN) hybrid electric aircraft concept. MAGIC features bi-directional conversion capabilities with 37.5-kW alternating current (AC) and 270-VDC. The biggest innovation on MAGIC comes from its fluid immersion-based cooling method. A dielectric fluid is directly flowed over all electronics to cool them efficiently without requiring access to airflow. Pressurizing the box for fluid flow also means it can withstand operation at high altitude.
Energy efficient technology
Motor Control Software
In an electrified aircraft propulsion system, a motor controller is used to operate the power converter that controls the motor. To help improve design and test processes, researchers at NASA developed a scalable control architecture that enables automatic generation of motor control software from a simulated environment. This makes the development process quicker and more efficient compared to traditional software development practices.
Resources
Publications
Explore and download a collection of publications highlighting NASA’s converter research and innovations.
Aircraft Concepts
Learn more about NASA’s conceptual aircraft design studies for future electrified aircraft.
EAP Labs and Testbeds
Learn about NASA’s labs and testbeds enabling advanced electrified aircraft propulsion research.
Technology
Discover the innovative systems and technologies that enable safe and efficient electrified propulsion.
