Abstract
This paper proposes a sliding-mode observer (SMO) based cascaded proportional-integral (PI) controller design for LC-filtered three-phase voltage source inverters (VSI). First, the proposed SMO-based PI-PI controller contributes to further improvements by providing good control performances in the transient state and steady state with minimal tuning effort as well as robustness against external disturbances and substantial parameter changes. Second, the overall stability including the SMO dynamics is guaranteed by using the Lyapunov theory. In order to validate the upgraded performance of the control system, simulation results using MATLAB/Simulink are presented. Also, the insight results are carried out to show superior performances such as fast dynamic responses, low THDs, small steady-state error (SSEs), and robust performance under three load situations (i.e., a step change in load, imbalanced load, and nonlinear load using a three-phase diode rectifier) with parameter uncertainties.