Design of IPMSM for reduction of eddy current loss in permanent magnets to prevent irreversible demagnetization

A design process for interior permanent magnet synchronous motor for reduction of eddy current loss in permanent magnet (PM) is presented. In order to minimize the temperature inside of the PM, the eddy current loss in PM is reduced by finite element analysis (FEA) and optimizing the core shape. Although the eddy current loss is 3-Dimensional (3D) problem, 2-dimensional (2D) FEA is employed to calculate the eddy current loss based on flux variation in PM calculated by 2D FEA. After then, prediction of the temperature in PM is performed by the thermal equivalent circuit network using a thermal source such as copper loss, iron loss and eddy current loss in PM. Lastly analysis of the irreversible demagnetization is conducted with the condition of the calculated temperature from the thermal equivalent circuit network.