Adaptive Sliding Mode Observer-Based Sensorless Control for SPMSM Employing a Dual-PLL

In order to get rid of the chattering problem of a sliding mode observer, this article presents an adaptive sliding mode observer (ASMO)-based sensorless control for surface-mounted permanent-magnet synchronous machines (SPMSMs). In the conventional sliding mode observer, a large gain is required to ensure the sliding motion stability. However, it leads to undesired chattering and degrades the position estimation accuracy. With the proposed ASMO strategy, the observer gain can be dynamically adjusted according to the back electromotive force (EMF), and it is applicable in wide speed range with improved estimation accuracy. Then, a dual-phase-locked loop (DPLL) is improved to extract accurate rotor position information under dynamic process in both positive and negative rotating directions of the SPMSM. Finally, the effectiveness of the proposed method has been verified by simulation and experiment on a Higale platform with a 0.2-kW SPMSM.