EEMF-Based Sensorless Control of PMaSynRM Drives Using Complex-Coefficient Filtering and Adaptive QPLL Tuning

This article proposes an enhanced extended electromotive force (EEMF)-based sensorless control strategy for permanent magnet assisted synchronous reluctance motor (PMaSynRM) drives. Conventional quadrature phase locked loop (QPLL) exhibits inherent position estimation errors during speed transients, while conventional sliding mode observer (SMO)-based methods suffer from severe high-frequency chattering. Moreover, the low-pass filter (LPF) used for EEMF extraction introduces phase lag and amplitude attenuation. To address these issues, a quasi-Newton-based adaptive QPLL tuning method is developed to improve the trade-off between dynamic response and noise immunity, thereby enhancing position estimation accuracy under varying operating conditions. In addition, a complex-coefficient filter (CCF) is introduced to replace the LPF for EEMF filtering, which effectively suppresses chattering while avoiding phase delay and amplitude attenuation at the center frequency. Experimental results on a 5.5-kW PMaSynRM test bench demonstrate that the proposed strategy effectively reduces position estimation errors and improves dynamic robustness under both speed and load transients.