Design optimisation of field-intensified permanent magnet machine

In this paper, with the application of an electric vehicle traction drive, the design optimisation of field-intensified permanent magnet machines is considered and explained. Two rotor types are considered in the design optimisation namely a simple salient-pole rotor and a rotor with internal flux barriers. The optimisation algorithm used is explained in detail and optimised machine structures are presented and discussed. Due to high torque ripple a new topology is implemented whereby the adjacent rotor poles and barriers are made asymmetric to avoid skewing the PM rotor. The FE results of the optimised machines are verified by laboratory measurements.