Choice of drives for electric vehicles: a comparison between two permanent magnet AC machines

Most motors for electric vehicles are based on the DC machine, nevertheless, the brushless surface mounted permanent magnet AC machine seems to be a good alternative. The authors propose a method of design and a comparison of two types of brushless machine that takes into account the requirements for the propulsion of electric vehicles. Two types of AC machine are designed taking into account the limitations due to the limited voltage power supply in terms of the airgap magnetic field shape and the corresponding stator current waveforms. Finally, a very simple analytical optimal design is proposed and verified both by numerical simulations and prototypes realisation.