Temperature-Dependent Demagnetization of Nd-Fe-B Magnets for Electrified Vehicles

This paper experimentally investigates temperature-dependent demagnetization of Nd-Fe-B magnets used in high power density permanent magnet synchronous machines (PMSMs) for electric vehicles. BH curves simulated using first-order, second-order and optimal temperature coefficients were compared with measured BH curves. A temperature control system was built to control the magnet temperature. Two N48H magnet samples were demagnetized by a demagnetization test fixture under various combinations of temperature and demagnetization field intensity. Simulation results of temperature-dependent demagnetization using the optimal temperature coefficient were compared with experimental test results. The insight gained in this work will help guide the electromagnetic design of PMSMs with enhanced anti-demagnetization capability at high temperatures.