Influence of PM flux variation and magnetic saturation on sensorless control for interior permanent magnet synchronous motors

Influence of permanent magnet flux variation and magnetic saturation on sensorless control for interior permanent magnet synchronous motors (IPMSM) is evaluated. By using FEM analysis, partial differential values of flux-linkage are calculated directly and precisely in a short time. High-speed analysis of a motor voltage equation is realized by interpolating table data of calculated partial differential values. Analyzed results show good correlation with experimental results. The performance of sensorless control is greatly improved using analyzed results and the influence of permanent magnet flux variation is predicted well. The proposed method is very useful for designing control algorithms considering the influence of permanent magnet flux variation and magnetic saturation.