Addressing the sensitivity of permanent magnet synchronous motors to external disturbances, a novel sliding mode control (NSMC) strategy is proposed to suppress sliding mode jitter and enhance speed regulation performance. First, an advanced non-singular fast terminal sliding mode (ANFTSM) surface and a new adaptive power rate reaching law (NAPRRL) were developed. A new switching function replaces the conventional sign function to enhance the system’s disturbance immunity and dynamic response speed. Then, the system’s anti-interference performance was further enhanced by introducing an improved novel sliding mode observer (INSMO) for feedback compensation of the aggregate disturbance. Finally, MATLAB/Simulink simulations and experimental validations demonstrate that the NSMC control strategy exhibits superior performance in both the start-up response and load disturbance phases, with enhanced dither-resistance, rapid dynamic response, and disturbance suppression capabilities.