Hub-mounted electric drive-train for a high performance all-electric racing vehicle

The authors describe how the brushless DC permanent magnet motor can be designed to very high specific outputs and is particularly suited for wheel-hub mounted, traction drives for electric vehicles, where low unsprung mass is highly desirable. Results to date on a prototype system have demonstrated a continuous specific power capability exceeding 2.4 kW/kg for the drive motor alone and 0.5 kW/kg for the entire electrical drive-train, that is the inverter, filter, motor and final gear reduction. However, rotor loss in permanent magnet machines remains a major issue and is exaggerated in these high specific output machines as a result of their inherent low inductance and the resultant operation with high current ripple