Multi-objective optimisation design and performance comparison of permanent magnet synchronous motor for EVs based on FEA

The requirements of high efficiency, power density, and low price for the motor of electric vehicles (EVs) make the design of the driving motor become a process of multi-objective optimisation. For purpose of the permanent magnet synchronous motor (PMSM) used for EVs has the higher efficiency, wider range of speed regulation with flux-weakening and better cost superiority, a multi-objective optimisation design approach based on finite element analysis (FEA) and modified particle swarm optimisation (MPSO) algorithm which takes efficiency, flux-weakening rate, and price as optimisation objectives is proposed in this study. Five PMSMs with different rotor topologies (V-shape, U-shape, double V-shape, delta-shape, and double tangential-shape) are optimised by the proposed optimisation method and their performance characteristics, including flux-weakening ability, efficiency, price, and anti-demagnetisation ability, are compared. The results suggest that double V-shape rotor topology has the wider constant power range and double-layer PMs topology has stronger anti-demagnetisation ability and wider high efficiency interval, whereas single-layer topology has lower cost price. Furthermore, a PMSM prototype with V-shape PMs is manufactured, so that the feasibility of multi-objective optimisation design approach and accuracy of FEA are verified by prototype experiments.