Enhanced Back EMF Sensorless Control for Permanent Magnet Synchronous Motors

Improvement of sensorless control of Permanent Magnet Synchronous Motors, is still an important industrial topic since this kind of electrical machines are still used for applications involving high performances, high levels miniaturization, heavy reliability. Typical examples are the propellers and actuators of marine and air drones or wearable equipment. In this work authors focused their attention on back-EMF techniques for sensorless control. Respect to current state of art, authors have investigated some smart filtering techniques in order to improve performance and reliability of motor speed control in known critical situations (low rotational speed of the motor). Respect to contributions available in literature and previous studies of the same authors, in this work are introduced some innovative issues related to the reduction of chattering and high frequency noise introduced in motor state by conventional estimators. By reducing these disturbances authors were able to improve the speed range in which the motor can be smoothly controlled minimizing noise, vibration and losses. Also authors performed an experimental campaign in which the proposed estimation and control algorithms are applied to different motors in order to verify performances, robustness and easiness of use of the proposed solution.