Sensorless Control of Permanent Magnet Synchronous Motors for Medium- and High-Speed Region

The research outlines the outcomes of utilizing methods based on a mathematical model of the motor for sensorless control of permanent magnet synchronous motors (PMSM) in the medium and high speed range using different strategies, such as Sliding Mode Observer (SMO), Pseudo-Sliding Mode Observer (P-SMO), Luenberger observer (LU) and Luenberger observer in quasi-synchronous γδ frame (LUγδ). The Back-EMF observer utilises stator voltages (u*), stator currents (i), and a mathematical model of the motor. An estimator, like a phaselocked loop (PLL) or an Atan function, is used to determine the rotor speed and position. As the accuracy of these estimates has a direct influence on the quality and dynamics of the sensorless control, precise Back-EMF signal observation is paramount. Additionally, the research exhibits how this was implemented on an actual motor. The results show that the investigated method is able to control the motor at medium and high speed with relatively low deviation between measured and estimated frame. This means that the deviation between the measured and estimated quantities is almost negligible. We conclude that this technique is highly appropriate for controlling the motor at medium and high speeds due to its robustness against parameter changes.