Optimization of external rotor surface permanent magnet machines based on efficiency map over a target driving cycle

Abstract

The external rotor surface permanent magnet (SPM) machine is attractively used for in-wheel traction application. In view of energy consumption, the efficiency of SPM machine over a driving cycle is more important than that at a single working point. This paper focuses on optimizing the external rotor SPM machine considering a target driving cycle. Under a target driving cycle, the whole motor working points are equivalent to several representative points. By using the SPM machine efficiency model, an external rotor SPM motor is optimized for the average efficiency of the target driving cycle, and validated by the finite element analysis (FEA).