Influence of Magnet Layout on Excitation Requirements for Post Assembly Rotor Magnetization in PM Motors : Used in Battery Electric Vehicles

This paper investigates the influence of magnet layout on the excitation effort required for post assembly magnetization (PAM) of permanent magnets (PM) in PM motor rotors. A modeling platform is developed and used to analyze interior PM configurations due to their prominence in battery electric vehicles, with findings applicable to other rotor topologies. Results show that increasing the PM angle toward a spoke-type arrangement reduces magnet saturation near the inner regions. The impact of this reduced saturation on back EMF, torque, and demagnetization of various rotor topologies are quantified, and measured back EMF from a prototype rotor with double V PM layout is compared with simulation predictions to verify the proposed models.