Two sliding mode based observers for sensorless control of PMSM

This paper develops two sliding mode-based observers for sensorless control of permanent magnet synchronous motor (PMSM) drives. These observers estimate the rotor position and speed from the stator currents and the DC-link,voltage measurements. The first observer uses the alphabeta stator reference, while the second observer uses an estimated dq(<^>) rotor reference. Both observer structures have two main parts. The first part is a sliding mode-based observer that uses the equivalent control to estimate a disturbance term containing information on the position and speed. The second part is a specific observer used to extract these desired variables. The observer designs the implementation aspects, and a comparative study on the extensive experimental results are given.