Adaptive Sliding Mode Control for Converters in Smart Grid System with Disturbances

Different types of converters have been serving as indispensable components in energy conversion process of smart grid, playing important roles in energy saving and efficiency promotion. In this paper, an observer based composite adaptive discrete-time sliding mode controller (ADSMC) is proposed for buck converter systems with mismatch disturbances. To eliminate the effects of multiple disturbances, a time-delay disturbance observer is first applied to have accurate estimations and subsequently compensated by designing an modified sliding surface. Further more, to alleviate the control input chattering and ensure shorter arrival time, a new adaptive discrete-time sliding mode reaching law is designed and applied. Religious stability and convergence analysis of the closed-loop system are presented. Finally, the effectiveness of ADSMC is verified by simulation results. As compared to the conventional discrete-time sliding mode controller, the proposed ADSMC can obtain higher voltage tracking accuracy and stronger disturbance rejection ability.