An Improved Rotor Flux Observer-Based Sensorless Control Method for Dual Three-Phase Axial Flux PMSM

Due to the remarkable performance, dual three-phase axial flux 33permanent magnet synchronous motors (DTP-AFPMSMs) are increasingly being adopted in the field of electric vehicles (EVs). However, the installation of position sensors limits the application scenarios of DTP-AFPMSMs owing to increased complexity, size and cost. This article proposes an innovative high-speed sensorless control method for surface-mounted DTP-AFPMSMs using an improved rotor flux observer. The proposed observer achieves precise rotor flux estimation by filtering out harmonic distortion and noise from the rotor flux of the first winding set using high-pass and low-pass filters, followed by a tracking-mode PI controller that accurately tracks the phase and amplitude of the rotor flux in the second winding set. Therefore, the proposed method can enable accurate rotor position estimation without the need for a phase-locked loop (PLL) and realise a more precise sensorless motor control. A series of simulations and experiments are carried out to validate the effectiveness of the observer, which reveals that the proposed method can effectively estimate the electrical position angle with a tiny error and presents a considerable improvement over the conventional method.