Sensorless permanent magnet synchronous motor drive with reduced order observer

In this paper, we present a new approach to the sensorless drive of permanent magnet synchronous motors based on the reduced order observer. First, we propose the new control inputs that decouple the d-axis current with the q-axis one. This enables us to construct the linear reduced order observer for estimating rotor speed and position. Owing to the linearization of the motor model, we can fix optimum gains of the observer under any operating condition. To confirm the validity of the proposed control scheme, experiments are carried out. The control is performed for the prototype of an eight-pole, 750 W permanent magnet synchronous motor by using the software with DSP-TMS320C31. The experimental results show high dynamic performance of the proposed control scheme.