Speed and position estimation technique for PMSM based on modified machine model

This paper presents a new sensorless speed and position estimation method for salient-pole Permanent Magnet Synchronous Motor (PMSM) based on a new mathematical model. All the system variables are expressed in a γδ estimated rotating reference frame. The modified back Electromotive Force (EMF) observer estimates the rotor speed and position utilizing the equivalent control signals of a sliding mode observer (SMO). PMSM parameter changes including stator resistance and permanent magnet flux are compensated by means of SMO. Additionally the initial rotor position is not needed for the overall observer implementation. Simulation results demonstrate the effectiveness of the proposed estimation method using Matlab/Simulink facility.