Fixed time control based on finite time observer for Buck converter system with load disturbance

Abstract

To improve transient response and reduce current ripple, a fixed time voltage regulation control strategy based on finite time observer for Buck converter is proposed in this paper. Different from the previous methods of adding additional circuits, the proposed fixed time controller combined with load finite time observer can be directly applied in integrated circuits. Meantime it avoids the chatter and vibration of sliding mode control strategy, relaxing constraint on initial condition of finite time control strategy. Firstly, a finite time observer is designed to estimate the uncertain load resistance. Secondly, combined with the backstepping method, a fixed time voltage regulation control strategy is designed by fixed time control theory, so that the output voltage has a credible ability to converge to the reference voltage in a fixed time. Finally, the proposed control strategy is verified by comparing with the finite time controller\cite{WB:8} and sliding mode controller\cite{WB:13}, where the obtained simulation and experiment results show the proposed strategy can make better performance in terms of convergence speed and ripple reduction when the reference voltage and the load change.