A Modified Flux Sliding-Mode Observer for the Sensorless Control of PMSMs With Online Stator Resistance and Inductance Estimation

In this article, the conventional flux sliding-mode observer (FSMO) is modified by taking the motor parameter variations into consideration, and an embedded flux observer is constructed to replace the conventional phase-locked loop for estimating the speed and position in the permanent-magnet synchronous motor (PMSM) sensorless control system. Compared with conventional FSMO, the improved method has certain robustness to parameter variations and improves the dynamic performance of the system under speed reversal. Furthermore, in the real experimental environment, after the long-term operation, the increasing of the motor temperature changes the values of the stator resistance and inductance. This phenomenon mismatches the actual and the setting motor specifications, which may induce ripples in the estimation results and affect the system stability. To address this issue, an online parameter estimation method is proposed in this article and incorporated into the modified FSMO to improve system performance and eliminate parameter mismatching. The control scheme of a PMSM prototype based on the proposed method is designed, and the corresponding experimental platform is built; the performance of the proposed method is validated and compared with that of the conventional FSMO via simulations and experiments.