A nonlinear reduced order observer for permanent magnet synchronous motors

This paper introduces a nonlinear reduced order observer for speed and rotor position estimation in permanent magnet synchronous motors (PMSMs). The observer is based on a model of the motor represented by stationary two-axes coordinates. The theoretical principles of the proposed observer are discussed. Sufficient conditions for convergence as well as convergence speed are established. The observer is designed and tested by simulation. The results show that the observer gives a good estimation of speed and rotor position. In addition, it has low sensitivity to torque disturbances and perturbations of the mechanical parameters.