We are pursuing the development of a new induction motor through innovative design with embedded drives enabling advanced electric drive technology to meet aircraft propulsion needs. The Phase II will continue to focus on the design improvements started in the Phase I: (1) power loss and cooling and (2) electric drive integration, and will also include the building and testing of a prototype motor and drive system. In this work, we have avoided the use of a permanent magnet (PM) based motor arrangement, which of course, would contain NdFeB magnets. Our concept incorporates an asynchronous (induction) style motor with embedded inverters and a two-phase semi-evaporative cooling system. Our total system (motor and drive) ultimately targets a continuous power density of 10 kW/kg and 12.6 kW/L or greater.
The motor and inverter design is based on two novel technologies and related controls for electric motors that have yielded record torque density and power density. The first novel technology is Variable Cross-Section Wet Coils (VCSWC) that configures the conductor windings with integrated cooling. The second technology is the integrated electronic drives, which are cooled as part of the same circuit that cools the stator, and which makes the full system very compact. Based on the results of the Phase I the proposed electric motor to be built in the Phase II should be a 2 MW, 5000 RPM machine that represents a number of advances over the extant OSU record-breaking induction motor, and will be a world record winning motor with double the torque and an increased power density (25% improvement to12.5 kW/kg, continuous) with, at the same time, an increased efficiency (98.5%, cruise). The Phase I/Phase II electric motor has an increased number of conductors per slot, and this is a key to loss reduction and increased efficiency. The Phase II will be focused on a design optimization within these basic parameters, and then a build and test program.
In addition to electric passenger aircraft, NASA can benefit from these high power density induction motors because of low cost, and high efficiency for space applications. Because these motors do not use permanent magnets, in the future NASA can avoid shortages of motors due to lack of availability of permanent magnet materials
These low cost, high efficiency induction motors can be used in passenger aircraft (eVTOL, 4-40 passenger aircraft, 40-400 passenger aircraft), trucks, trains, ships, and cars. Because these motors do not use permanent magnets, in the future commercial customers can avoid shortages of motors due to lack of availability of permanent magnet materials