Emphasis in the electrical machines activity is on advanced motor technologies, performance, low-cost materials, and thermal management systems that will yield higher power densities and cost-effective solutions. Induction motors have the advantage of being the most widely manufactured and used, but they cannot meet the FreedomCAR and Fuel Partnership requirements of cost, weight, volume, and efficiency; and the likelihood of achieving additional improvements is low because the technology is already mature.
A permanent magnet motor has the highest power density; but it does not have a sufficient constant power speed range, and its cost is too high. Switched reluctance motors are potentially the lowest-cost candidate but have serious problems of high torque ripple, high noise, and low power factor.
The Automotive Electric Motor Drive (AEMD) task has developed an external permanent magnet motor that met the power requirements but fell considerably short of cost, weight, and volume goals for the FreedomCAR and Fuel Partnership. Future research will focus on alternate designs for a permanent magnet motor and on field weakening to increase the constant power speed range. The unacceptably high cost of permanent magnet motors is due to the high cost of magnet materials, magnet manufacturing, and rotor fabrication. Research is being conducted on polymer-bonded particulate magnets with the objectives of increasing the useful operating temperature from 150°C to 200°C and decreasing the cost to about 25% of the current price of approximately $90 per kilogram.