Sensorless non-salient permanent magnet synchronous motor drive using sliding-mode observer

This paper presents a new strategy in starting a non-salient sensorless permanent magnet synchronous motor (PMSM) and in estimating the rotor flux position and the rotor speed of the motor. The sensorless algorithm is based on sliding-mode control technique, in which a switching surface using the error vector between the observed and actual stator currents is defined. First, a simple strategy proposed for the start-up of the PMSM is introduced. Next, the detailed theory and the proof of the stability of the sliding-mode observer based sensorless algorithm are described. Then, a field-oriented control PMSM drive using current-controlled voltage source inverter (VSI) is built for the implementation of the proposed start-up strategy and sensorless algorithm. Moreover, to test the speed control characteristics of the sensorless drive, both the integral-proportional (IP) and fuzzy neural network (FNN) controllers are implemented as the speed controller for comparison. In addition, the sensitivity of the sensorless algorithm to the electrical parameter variations is discussed. Finally, some simulated and experimental results are demonstrated to show the effectiveness of the proposed start-up and sensorless algorithms.