Rotor position estimator using non-linear observer of surface permanent magnet synchronous motor

This paper presents a new estimation method of rotor position to achieve a position sensorless control for surface permanent magnet synchronous motor. DC current adds to SPMSM and nonlinear observer is applied to the torque equation to estimate the rotor position from the induced voltage while the motor is vibrating. When the error of the measured and calculated induced voltage is converged, the estimated rotor position is converged to the real value. The validity of the proposed method is verified by the experiment.