A Study on the Effect of Eddy Current Loss and Demagnetization Characteristics of Magnet Division

Permanent magnet motor is used in various fields because of their relatively small size, high power and high efficiency. However, an electric machine performance using permanent magnet can be decreased as temperature, humidity, and magnetic field related demagnetization phenomenon. Therefore, the motor should be designed considering the demagnetization characteristics. In this paper, the demagnetization characteristics and eddy current loss of a BLDC motor generator are analyzed according to magnet segments. For the comparison of eddy current loss, 3D analysis is performed by dividing the magnet into Non segment, three segments, five segments, and seven segments. The magnet demagnetization according to the change in eddy current is analyzed. The rotor temperature is measured to determine the difference in heating caused by the change in eddy current loss. The electromagnetic characteristics are analyzed by ANSYS EM 19.0. The validity of the results is verified by comparing the simulation and experimental data.