Nonlinear observer for the PM synchronous motor

This paper deals with nonlinear states and parameters estimation of a permanent magnet synchronous motor (PMSM) without mechanical sensors. In the proposed method, a change of coordinates is established in order to transform the PMSM system into an observer form which enables us to apply an adaptive or a high gain observer. Then the load torque, rotor speed and some parameters can be estimated from both measurable currents and voltages. The efficiency of the proposed methods is illustrated by the simulation results.