Magnetization modeling of a bonded magnet for performance calculation of inner-rotor type BLDC motor

In many cases, ferrite bonded magnets used in inner-rotor type brushless DC (BLDC) motors do not have rotor core, and the magnetization directions of permanent magnets do not have only parallel or radial direction. The characteristics of magnets are different from cored type ones which have uniform magnetization direction. In this paper, the magnetization directions and intensities of a ferrite bonded magnet are analyzed by finite element analysis for magnetization procedure. The characteristics of an inner-rotor type BLDC motor are analyzed by using the determined magnetization. The analysis results are compared with the measured ones.