A Study on the Application of Groove Structures for Reducing Eddy Current Loss in Axial Flux Permanent Magnet Motors

Eddy current losses generated in permanent magnet motors during high-speed operation cause internal heating of the magnets, leading to a temperature rise that can result in irreversible demagnetization. This phenomenon directly affects the output stability and reliability of the motor. In particular, high-performance materials such as NdFeB-based rare-earth magnets exhibit high temperature sensitivity, requiring careful consideration during the design process. A common method for suppressing eddy current losses is to segment the magnets, thereby interrupting the path of the induced currents. However, such physical segmentation increases the complexity and cost of precision machining and assembly, and presents significant challenges when applied to axial flux motors. In this study, an integrated magnet structure is proposed that effectively controls eddy current paths without requiring segmentation. The proposed design is evaluated using three-dimensional finite element analysis to compare torque characteristics, induced current distribution within the magnets, and the resulting eddy current losses with those of a conventional design.