Design and Optimization of an In-wheel Unequal Stator Teeth Motor

Abstract

Recently, many researches have been focusing on finding new machine topologies that maximize the efficiency and minimize the mass of in-wheel motors for electric vehicles. This paper presents the design and the optimization of a new in-wheel motor for electric vehicles. This was achieved by proposing a new topology including unequal stator teeth. The design of the machine was performed with an analytical model that considers the slotting effect and the saturation when calculating the air gap flux density. The main purpose of the optimization process is to determine the optimal machine geometric dimensions. This optimization was performed according to three objective functions while respecting a set of constraints. The first objective function is to maximize the machine’s efficiency, the second is to minimize the mass, and the third is to minimize the torque ripple. In this regard, four multiobjective optimization algorithms were employed: two of them belong to the particle swarm optimization family, and the others are genetic algorithms. An optimized machine design was chosen and analyzed using finite element analysis (FEA). The comparison of FEA and optimization results showed a good agreement between both of them, and proves the validity of the proposed design.