Extended EMF Observer of Dual Three-Phase Permanent Magnet Synchronous Motor Operable in Overmodulation Drive

Abstract

This paper proposes a novel extended electromotive force (EEMF) observer of a dual three-phase permanent magnet synchronous motor (DTP-PMSM) operable to the position sensorless overmodulation drive. The overmodulation drive occurs in current harmonics, and the estimated EEMF also contains harmonic components, leading to ripple error in the estimated position. Based on the vector space decomposition (VSD) utilized in DTP-PMSM current control, the proposed method can decrease the current harmonics in the overmodulation and the harmonic components in the estimated EEMF, and it can also improve position estimation. The effectiveness of the proposed EEMF observer and the improvement in the position estimation were experimentally verified.