Sensorless Control of Permanent Magnet Synchronous Motors Based on Novel Position Angle Extraction With SMO

This paper presents an improved sensorless controller scheme for a robust permanent magnet synchronous motor. Firstly, a sliding mode observer based on a variable rate approach rate is designed to observe the back electromotive force, enhance the robustness of the back electromotive force acquisition process, and reduce the system buffeting. Secondly, the concept of finite control set model predictive control is introduced, and the position angles are divided into small angles to form finite control sets. Then the position Angle of the finite control set is entered into the sliding mode observer to calculate the back electromotive force. At the same time, the optimal position angle is obtained based on the cost function of the back electromotive force. In order to reduce the number of iterations, the dichotomy is adopted to reduce unnecessary calculations. The proposed finite position-set phase-locked loop (PLL) avoids the PI controller in the traditional PLL and further improves the robustness of the system. Finally, the effectiveness of the proposed scheme is verified by relevant experiments.