Inverse Estimation Method of Permanent Magnet Magnetization Using No-load Back Electromotive Force of Permanent Magnet Synchronous Motor

A high-accuracy magnetization process of permanent magnets (PMs) is desirable for manufacturing a high-performance PM synchronous motor (PMSM). Therefore, estimating the PM magnetization on a manufacturing process is essential. After the post-assembly magnetization of a PM loaded on a PMSM, the no-load back electromotive force (EMF) is utilized for estimating the magnetization condition of the PM. However, the estimation involves comparing the no-load back EMF measured using reference PM. Therefore, the PM magnetization is indirectly estimated. In this letter, a direct estimation method of magnetization of the PM of a PMSM using a back EMF of the PMSM is proposed.