Sensorless Control of Nonsinusoidal Back-EMF PMSM Based on State Observer

This paper presents a sensorless vector control method based on current and back-EMF state observers for a surface-mounted permanent magnet synchronous machine (PMSM) with nonsinusoidal back electromtive force (EMF). The mathematical modeling of the PMSM is presented in the stationary reference frame. The estimated rotor position is presented in terms of flux linkage in the stationary reference frame. Then, current and back-EMF observers are used, in order to obtain both actual and observed αβ currents and αβ EMF. The performance of the proposed approach for speed and current control is demonstrated by simulation results.