The simulation of low core loss high speed permanent magnet motor based on soft-magnetic ferrite

Abstract

High core loss is the most outstanding problem in high speed permanent magnet motors. To solve this problem, water cooling or oil cooling is usually adopted, which increase the complexity and cost. Considering the characters of high permeability, high resistivity, low loss and low cost for soft magnetic ferrite, this paper proposes a novel high speed PM motor based on soft magnetic ferrite. Soft magnetic ferrite ring is used as stator core, rare earth PM ring serves as the rotor poles, and the slotless configuration with long effective air gap is adopted. The size matching design between the stator magnetic ring and the PM magnetic ring can make themselves work in their best operating points respectively, lower core loss and higher power density will be ensured in the motor. The results of magnetic field analysis, core loss analysis and the prototype test prove that the core loss can be greatly reduced, which verifies that the high speed PM BLDC motor based on soft magnetic ferrite is feasible.