A synchronous coordinates approach in position and speed estimation for Permanent Magnet Synchronous Machines

A novel and simple observer scheme is proposed for rotor speed and position reconstruction for Permanent Magnet Synchronous Machines. The reference frame adopted in the observer is pushed toward the synchronous one by forcing it to be intrinsically aligned with the estimated back-emf vector and by designing suitable adaptations law for its speed and angle along with the back-emf amplitude. Stator flux dynamics are not used in this approach, leading to an improved robustness with respect to voltage and current measurement uncertainties. Stability analysis is carried out by using singular perturbation approach. Effective tuning rules are drawn exploiting insightful linearization of the proposed nonlinear adaptive observer. Simulations show the properties of the presented method.