High Efficiency Axial Flux Permanent Magnet Machine Design for Electric Vehicles

Abstract

Design and optimization of electrical machines for electric vehicle (EV) applications is achallenging task. In response to variable driving circumstances, the machine should be designedto operate in a wide range of speed and torque. This paper aims to optimize a surface-mountedaxial-flux permanent-magnet (AFPM) traction machine taking the influence of the driving cycleinto account. The AFPM motor is designed to maximize the overall efficiency over a predefineddriving cycle. EV requirements and geometric constraints are taken into account in the designprocess. Hundreds of operating points in a driving cycle are reduced to the limited number ofrepresentative points by calculating the energy centre points in the energy distribution curve.Therefore, the number of calculations during the design optimization is significantly reduced. Ananalytical design procedure based on quasi-3D approach is used for accurate modelling of AFPMmachine and genetic algorithm (GA) is implemented to find out the optimal design parameters.Functionality of the proposed approach is validated via comprehensive three-dimensional (3D)finite-element analysis (FEA).