Sensorless Predictive Control of Series/Open-End Winding PMSM Drives Using Third-Harmonic Back EMF Observer and Iterative PLL

Series and open-end winding permanent magnet synchronous motor (PMSM) drives necessitate precise control of the zero-sequence current (ZSC) to ensure optimal performance. In model predictive control (MPC), the ZSC is managed through the motor model, which requires accurate estimation of the third-harmonic back electromotive force (EMF). This paper presents a novel sensorless control method leveraging third-harmonic back EMF for simultaneous rotor position estimation, eliminating the need for additional observers in the control algorithm. A second-order generalized integrator (SOGI) is employed to observe the third-harmonic back EMF, while a Newton-Raphson iterative algorithm is utilized as a phase-locked loop (PLL) to extract rotor position. Additionally, a disturbance observer-based speed control strategy is implemented to enhance dynamic performance. The proposed method integrates finite control-set MPC to regulate dq-axis currents and ZSC effectively. Simulation results validate the accuracy of the proposed methodology, demonstrating its efficacy in sensorless operation of series/open-end winding PMSM drives.