Recent Development of Online Parameter Estimation of PMSMs

Online parameter estimation is essential for improving the control performance, efficiency, and reliability of permanent magnet synchronous machine (PMSM) drives. Numerous parameter estimation methods have been proposed for both position sensor-based and sensorless control. This paper presents a comprehensive review of recent developments in online parameter estimation for both three-phase and multi-phase PMSMs. Conventional methods for addressing the rank-deficiency issue, including partially fixed parameters, additional measurements, harmonic extraction, signal injection, and variable-speed excitation, are first summarized. Subsequently, the challenges of parameter estimation under sensorless control are discussed, followed by a review of virtual back-EMF, virtual extended-EMF, virtual flux linkage, and virtual active flux injection methods. Finally, recent advances in dual three-phase PMSMs are reviewed by exploiting the additional degrees of freedom provided by multi-phase machines. The advantages, limitations, and future research directions of representative parameter estimation methods are also discussed.