SBIR Phase I: Fault-tolerant drive for High-Power-Density Motors

This Small Business Innovation Research Phase I project will prove the feasibility of a high reliability motor drive optimized for lightweight propulsion systems for electric aircraft. The NASA green flight challenge proved the viability of electric flight with a 400 passenger mile per gallon pure electric flight last year, but products specific to this market are not yet available. Presently available motor drives limit the reliability of electric propulsion system to unacceptably low levels. These drives are designed for ground vehicles and have reliability significantly less than general aviation planes. These drives also require heavy load inductors to interface with the highest power density electric motors. The novel drive architecture proposed will provide high reliability and operate directly with low inductance motors in the 10 kW to>250 kW range. Rigorous reliability analysis techniques from the commercial aviation industry will be applied to system models to optimize the architecture for reliability and power density. The design will be validated in hardware by fabricating and testing a single phase of the drive. This drive coupled with an advanced motor will form an electric aircraft propulsion system with the highest power density available and a reliability level consistent with aviation usage. The broader impact/commercial potential of this project is to address a developing market for propulsion systems that will enable non-polluting and reliable electric aviation in the small aircraft and Unmanned Aerial Vehicle (UAV) sectors. UAV use is expanding rapidly. Many domestic applications of UAVs such as law enforcement or surveying could be served by electric UAVs. Congress has mandated that the FAA integrate UAVs into the airspace, but present UAVs do not have reliability levels consistent with use in the civilian airspace. General aviation is looking to electric flight as a way to reduce operating costs and greenhouse emissions in an age of ever increasing fuel prices and concern for the environment. The FAA is updating regulations to create a class of "Electric Light Sport Aircraft" (eLSA), but no commercially available motor drives meet general aviation reliability levels. This project will combine rigorous commercial aviation high reliability electronics design techniques with power electronics designs from heavy industry motor drives to create an electric aviation motor drive that is lightweight, fault tolerant, and highly reliable. The proposed drive will have reliability levels consistent with operation of electric aircraft in the civilian airspace while still retaining exceptional power density.