To　address　the　challenges　of　single　current　sensor　(SCS)　control　in　Permanent　Magnet　Synchronous　Motor　(PMSM)　drives,　this　paper　proposes　a　novel　discrete-time　current　state　observer　control　method.　Traditional　discretization　techniques,　such　as　Euler＇s　and　Tustin＇s　methods,　are　widely　used　in　observer-based　control　but　have　notable　limitations:　Euler＇s　method　introduces　significant　discretization　errors　and　potential　instability,　while　the　Tustin　method　improves　numerical　stability　at　the　cost　of　increased　computational　complexity,　placing　higher　demands　on　processing　resources.　To　overcome　these　issues,　this　paper　first　analyzes　the　performance　of　state　observers　based　on　these　conventional　methods　and　a　fourth-order　Runge-Kutta　hybrid　discretization　approach.　Then,　a　new　discretization　scheme　is　introduced,　leading　to　the　development　of　a　discrete-time　adaptive　observer,　which　significantly　enhances　discretization　accuracy　while　ensuring　computational　efficiency.　To　validate　the　effectiveness　of　the　proposed　approach,　extensive　simulation　experiments　are　conducted　in　MATLAB/SIMULINK　under　various　operating　conditions.　The　results　demonstrate　that　the　proposed　observer　improves　current　reconstruction　accuracy,　enhances　system　stability,　and　ensures　reliable　PMSM　operation,　making　it　a　cost-effective　and　computationally　efficient　solution　for　SCS-based　motor　drives.　©　2025　IEEE.