Comprehensive Analysis of Extended Electro Motive Force Observers for Position Estimation in Interior Permanent Magnet Synchronous Machines

Extended Electro Motive Force observers exhibit good performances at medium and high speeds. However, voltage and current errors, together with parameter uncertainties, lead to inaccurate rotor position estimation. Thus, this paper proposes a novel analytical approach to identify estimated position errors of Extended Electro Motive Force Observers in both the stationary and the estimated synchronous reference frames. A unified analytical framework is presented, that allows to derive a closed-form expression for these errors in both frames. Steady state errors are extensively investigated with respect to stator resistance mismatch, inductances mismatch, voltage distortion, and current measurement errors. Results are validated through simulations.