To address the decline in drive system efficacy due to uncertainties in the model, variations in parameters, and interruptions from external sources affecting permanent magnet synchronous motors (PMSMs), a novel control strategy is proposed. First, to reduce the reliance on the system’s mathematical model, a new super-twisting algorithm is formulated for the speed loop of the PMSM. Secondly, based on the new super-twisting model of the speed loop, a novel model-free super-twisting fast integral terminal sliding mode controller (MFSTFITSMC) is designed by integrating a new type of integral terminal sliding surface and an improved super-twisting control law, achieving precise control of the motor speed. Furthermore, a non-singular fast terminal sliding surface and a dual-power approaching law are used to devise an improved extended nonsingular terminal sliding mode disturbance observer (IENTSMDO). This observer accurately detects and provides feedforward compensation for unknown disturbances, effectively suppressing parameter perturbations and external disturbances, thus enhancing the system’s robustness and improving both dynamic and steady-state performances. Finally, through simulation and experimental comparison with traditional control methods, the proposed algorithm has been verified to improve speed overshoot resistance by 0.412 5% and enhance the torque response speed by 0.013 s. The results indicate that the proposed method possesses strong robustness and good interference rejection capabilities in the presence of unknown disturbances.