Shivang with adviser A. Banerjee
Turboelectric propulsion uses no batteries for propulsive energy during any phase of flight (unlike hybrid and all-electric systems) and is considered a critical enabler for low-carbon emissions in the aircraft industry. As batteries with high enough power capacity and the specific power required for commercial aircraft are unlikely to be developed within the next 30 years, turboelectric systems are the only feasible option.
A brushless doubly-fed machine (BDFM) is attractive for megawatt-scale turbo-electric propulsion systems due to use of a partially-rated power converter, reduced maintenance, and absence of permanent magnets. However, the BDFM has poor torque density because of machine saturation, even at low current density. This offsets all the benefits. Figure 13 shows the BDFRM drive architecture. We have proposed an approach to maximize the torque density by finding appropriate electrical excitations on the two stator windings for a given machine dimension while remaining within flux- and current-density limits. The machine torque capability is enhanced by 75% for an identical machine dimension while simultaneously improving the power factor of the secondary stator, and hence reducing the power converter size. The overall efficiency also increases with the proposed design. This research is supported by Grainger Center for Electric Machinery and Electromechanics.