Drive system design for an electric vehicle based on alternative motor types

This paper compares three different AC motors as potential candidates for use in an electric vehicle drive. The conventional squirrel cage induction motor is taken as a reference in terms of its ability to operate over a wide speed range with a suitable inverter drive, and its operating efficiency over the torque-speed plane. Motors using the same stator but two different rotors are compared with the reference machine. The first alternative rotor uses surface mounted permanent magnets while the second is a composite rotor with a surface mounted permanent magnet section and an axially laminated reluctance section mounted adjacent to each other on the same axis. Measurements have been made on experimental machines to derive the torque-speed envelope and the efficiency map over the operating area for each machine