Abstract: With the continuous development of new energy technologies, the research on three-phase inverter control strategies has become increasingly important. However, the traditional control methods have the drawback of poor dynamic response. This paper addresses the difficulties in precise modeling of three-phase inverters, internal parameter perturbations, and external unknown disturbances. It proposes a non-singular terminal sliding mode controller (NTSMC) based on the generalized proportional-integral observer (GPIO). Through GPIO, it observes the total disturbances and performs feedforward compensation to improve the control accuracy and fault-tolerant capability under various disturbances. Compared with the traditional PI control, this strategy has the finite-time convergence of voltage tracking error and active anti-interference ability. Finally, simulations were conducted in the MATLAB/Simulink environment, and a hardware experimental platform was built under laboratory conditions. The simulation results show that, in the presence of disturbances, the proposed control strategy has better robustness and smaller jitter. The experimental results indicate that the controller eliminates the current sensor and has active anti-interference capability. Under disturbance conditions, the jitter and overshoot of the output voltage are significantly reduced.