This study aims to improve the stability and reduce chattering in the sensorless control system of surface-mounted permanent magnet synchronous motors (SPMSM) utilizing a sliding mode observer. An enhanced super-twisting sliding mode observer incorporating fuzzy logic optimization is presented. Initially, the sliding mode gain is adaptively tuned via a fuzzy control strategy to boost observer robustness. Subsequently, a newly designed continuous switching function replaces the conventional sign function, substantially mitigating system chattering. Furthermore, a phase-locked loop (PLL) is implemented instead of the arctangent function to elevate estimation accuracy. Simulation outcomes confirm that the proposed approach effectively curbs chattering and strengthens overall system stability.