Multi-physics and multi-objective optimisation design of interior permanent magnet synchronous motor for electric vehicles

The electrical machine design method plays a decisive role in electric vehicles (EVs). However, only a few designs consider the coupling of multiple fields simultaneously. This study proposes an improved multi-physics and multi-objective optimisation design approach for designing a 75 kW interior permanent-magnet synchronous machine dedicated to EVs. Five optimal objectives including power density, temperature rise, price, torque ripple, and cogging torque are selected, and the first three objectives are optimised based on the sensitivity analysis of design parameters, where an improved thermal resistance network combining with finite-element analysis model is developed. Meanwhile, the torque ripple and cogging torque are involved in subsequent design optimisation. The temperature rise and structural strength are recalculated by using commercial finite-element model software, respectively, for validating the accuracy of optimisation design. Finally, a prototype motor is manufactured; both simulation and experimental results verify the feasibility and validity of the proposed optimisation design method.