Rotor Design to Prevent PM Irreversible Demagnetization of Axial Flux Permanent Magnet Motors

The application of Soft Magnetic Composite (SMC) cores and Nd bonded magnets, known for their ease of manufacturing in various shapes and low-loss characteristics, has been implemented in the development of Axial Flux Permanent Magnet Motors (AFPMM) for EV traction in this paper. However, these components exhibit lower residual magnetic flux density and coercive force characteristics when compared to Nd sintered magnets. Consequently, there is a crucial need to enhance both the electromagnetic field performance and design strategies to effectively mitigate the potential risk of irreversible demagnetization in permanent magnets, a critical consideration for EV traction motors. Despite the advantages of SMC cores and Nd bonded magnets, there remains a gap in research concerning the electromagnetic field performance of AFPMM and the characteristics of irreversible demagnetization with various shapes of Nd bonded permanent magnets and SMC cores. This study addresses this gap by investigating the electromagnetic field performance and irreversible demagnetization characteristics of AFPMMs, specifically focusing on different shapes of Nd bonded permanent magnets and SMC cores. By employing a consistent quantity of permanent magnets at the same operating point, improvements in the electromagnetic field performance of AFPMM are achieved, and designs aimed at preventing irreversible demagnetization are implemented.