An Extended Flux Model-Based Rotor Position Estimator for Sensorless Control of Salient-Pole Permanent-Magnet Synchronous Machines

Starting from the classical dynamic model of salient-pole permanent-magnet synchronous machines (PMSMs) expressed in the stationary reference frame, this paper presents a mathematical model reconstruction process for salient-pole PMSMs, from which an extended flux-based machine model is derived. Compared with the commonly used extended electromotive force-based model, the extended flux-based model has notable advantages of simpler model structure and less sensitive to the variations of machine parameters and operating conditions. A new extended flux model-based rotor position estimator is then proposed for sensorless control of salient-pole PMSMs by utilizing a sliding-mode observer with a dynamic position compensator. The latter improves the dynamic performance and low-speed operating capability of the sensorless control system. Both simulation and experimental results are provided to validate the proposed rotor position estimator and the sensorless control system for salient-pole PMSMs.