Nondestructive Inverse Estimation Method of Permanent Magnet Magnetization Using No-load BEMF of PMSM

Because a magnetization process of permanent magnet (PM) with high accuracy is desirable for manufacturing a high-performance PM synchronous motor (PMSM), the PM magnetization estimation in the design process is essential. After the post-assembly magnetization of PM loaded on the PMSM, the no-load back electromotive force (no-load back EMF, hereafter abbreviated as BEMF) is utilized for the simple estimation of the magnetization condition of PM. However, since the estimation is performed by comparing the back EMF measured under the no-load condition with the reference PM, the PM magnetization is not directly estimated. In this study, the direct estimation method of PM magnetization using back EMF of PMSM is proposed.