Lightweight design of the in-wheel motor considering the coupled electromagnetic-thermal effect

The lightweight problem of in-wheel motor is one of the key problems to be solved in the development of in-wheel motor driving electric vehicles. However, in-wheel motor involves the cross-coupling effect of multi-physical fields, such as the structure field, electromagnetic field and thermal field. The lightweight design for the in-wheel motor means the change in the structure, which will lead to the change in other physical field characteristics. Aiming at this problem, a lightweight design method is proposed in this paper. A 15Kw embedded permanent magnet synchronous in-wheel motor is taken as the research object, the minimum volume is set as the optimization objective, and the topology optimization design method is adopted to reduce the weight of the motor. And in the optimization design process, the bilateral coupling constraint of the electromagnetic field and thermal field is taken into account simultaneously. This study aims to find the optimal topology distribution considering the cross-coupling effect of structure-electromagnetic-thermal fields, and obtain the optimal structure of the in-wheel motor that meets the design requirements. Furthermore, the validity of the lightweight design method is verified by comparing and analyzing the characteristics of each physical field of the in-wheel motor before and after optimization.