This paper presents a comparative analysis of two interior permanent magnet synchronous motors (IPMSMs) using rare-earth (RE) permanent magnet (PM) and rare-earth-free (REF) PM for electric vehicle (EV) traction. Both motors are designed with the same...
This paper presents a comparative analysis of two interior permanent magnet synchronous motors (IPMSMs) using rare-earth (RE) permanent magnet (PM) and rare-earth-free (REF) PM for electric vehicle (EV) traction. Both motors are designed with the same outer dimensions and operated under identical output conditions, while exhibiting similar back-EMF characteristics within the voltage limit. An electromagnetic–thermal coupled analysis is employed to account for loss-induced temperature variations during driving cycles. Energy efficiency is evaluated under UDDS and HWFET driving cycles. The results show that the REF model exhibits slightly lower energy efficiency than the RE model, with a difference of 1.33% under UDDS cycle and 0.55% under HWFET cycle. In particular, under high-speed and steady driving conditions, the difference in energy efficiency remains below 1%, indicating that the performance degradation of the REF model is limited. These results suggest that REF PM based IPMSM can be a viable alternative for EV traction motors under appropriate driving conditions.