Design, analysis and fabrication of a high-performance fractional-slot concentrated winding surface PM machine

A high-performance 55 kW (peak) fractional-slot concentrated winding (FSCW) surface permanent magnet (SPM) machine has been designed to meet demanding performance requirements based on the FreedomCar advanced traction motor requirements prepared by the US Department of Energy. This paper describes key steps in the design, analysis, fabrication, and testing of this machine. Design challenges arising from the high-speed, high-efficiency requirements are presented followed by a discussion of design features that have been introduced to address them. A prototype version of the machine has been fabricated using a segmented stator configuration and segmented neodymium-iron rotor magnets. Test results gathered to date demonstrate promising torque production and efficiency characteristics that are consistent with the machine performance predictions.