Thermal Analysis of BLDC Motor With Propose New Arrangement for Permanent Magnets to Magnet Eddy Current Loss Reduction

NdFeB permanent-magnets (PM) are very often used in the PM machines due to their high energy density. As the NdFeB-magnets are good electric conductive materials, electric currents are induced in the magnets when they are exposed to a varying magnetic field. The temperature rise due to eddy current loss in the PM leads to serious deterioration of the PM, especially in high speed operation. To reduce the eddy current loss produced in the PM, many studies have presented, and proposed several schemes, including the segmented PM. In this paper, a new structure based on segmentation was proposed to optimize the eddy current loss. Then “transient thermal circuit” is used for thermal analysis of BLDC motor, and thermal circuit are implemented in PSpice to calculate temperature of various parts of motors. Thermal analysis is carried out for both solid and optimization model of permanent magnet and their results are compared.