Sliding Mode Observers Combined with Locked Loop Techniques for Sensorless Vector Controlled Synchronous Reluctance Machines

This paper presents a comparative study of four different rotor position and speed estimation methods for sensorless vector control of synchronous reluctance machines (SynRMs). The estimation methods are based on the active-flux concept, the different sliding-mode observers (SMOs) and locked loops. For SMO control vectors, a signum function and a super-twisting algorithm are used. The SMOs are combined with phase-locked loop (PLL) and dual second-order generalized integrator frequency-locked loop (DSOGI-FLL) for position and speed extraction from observed active flux derivatives. The methods are verified and compared by simulation tests in MATLAB Simulink. The saturable SynRM model is used, and parameter sensitivity analysis is performed.