Discrete-time sliding mode control for output voltage regulation of three-phase voltage source inverters

This paper presents the application of discrete-time sliding mode control for the output voltage regulation of three-phase PWM VSI systems. The effect of computational and pulse width implementation delay on the stability of the closed-loop system is analyzed and the switching function for the sliding mode is selected appropriately to compensate the effect of computational time delay. The tracking performance of the control scheme is demonstrated in terms of transient and steady-state characteristics by simulation and experimental results. The invariance and the robustness features of the control are verified in the presence of large uncertainty in parameters and external perturbations. The performance of the voltage control scheme is also verified under unbalanced load conditions.