Cascaded Generalized Super-Twisting Observer Design for Sensorless PMSM Drives

This brief investigates the use of a new cascaded generalized super-twisting observer (GSTO) for sensorless permanent magnet synchronous motor (PMSM) drives. Specifically, the developed first-stage observer extracts information about internal back-EMF, and then, ensures that the estimation error converges to an arbitrarily small region within a finite time. Meanwhile, the second-stage observer reconstructs the position and speed information synchronously, which can improve the transient performance to a certain extent compared with the arctangent function calculation-based technique. The benefits of the proposed strategy lie in that the cascaded configuration of the two observers minimizes the high-frequency noise of the back-EMF reconstruction system and provides accurate estimations of rotor position and speed. Furthermore, the chattering problem commonly seen in the conventional sliding mode observer (SMO) can be avoided in the presented scheme. Experimental results validate the effectiveness of the proposed methodology.