Reduced-Order Adaptive Observer With Asymptotic Stability for Sensorless Control of SPMSM

The design of the back electromotive force (EMF) observer is important in sensorless speed control of surface-mounted permanent magnet synchronous motors. However, many existing back EMF observers are coupled with the phase-locked loop (PLL), which not only complicates observer design but also poses challenges in ensuring global asymptotic stability. To address this challenge, this article introduces a reduced-order adaptive observer (ROAO) characterized by PLL-independent, which greatly simplifies the parameter design of the observer. In addition, the proposed ROAO is globally asymptotically stable with rigorous proof via the Lyapunov theorem. Finally, the effectiveness of the proposed observer is verified by simulation and experiment.