An Adaptive SMO Approach for Low-Chattering Sensorless Control of PMSM

This article presents a sensorless control strategy for permanent magnet synchronous motors (PMSMs) with low chattering based on an adaptive sliding mode observer (SMO). The strategy incorporates an improved SMO with a novel adaptive fast power reaching law (NAFPRL-SMO) and a higher-order phase-locked loop based on an extended state observer (ESO-HOPLL). First, the NAFPRL-SMO is designed with adaptive gains to address the issue of slow reaching velocity that is commonly associated with traditional power reaching laws when far from the sliding mode surface. This is achieved by utilizing system state variables for enhancement. Then, to effectively suppress the chattering phenomenon, a sigmoid function is employed as a switching function. Finally, the ESO-HOPLL structure is utilised to reduce the effects of differential noise and improve the performance of the system, allowing for precise estimation of rotor position and speed information. Simulations and experiments are conducted to validate the steady-state and dynamic performance of the proposed sensorless control strategy, demonstrating its effectiveness and potential for enhancing performance in PMSM applications.