Demagnetization fault diagnosis of PMSM based on analytic inductance calculation

Demagnetization fault of Permanent magnet synchronous machine (PMSM) degrades motor´s performance. As the strength of permanent magnet (PM) decreases, inductance of the PMSM changes since flux density affects electrical steel´s nonlinear characteristics. It makes difficult to estimate exact flux linkages of the PMSM to diagnose demagnetization fault. In this paper, we suggested analytic inductance prediction considering magnetic saturation effect and varying flux linkages of PMSM, which shows better results in estimation of flux linkages. Finite Element Analysis (FEA) results demonstrate that the proposed method works well.