Adaptive saturated finite-time control algorithm for buck-type DC-DC converter systems

Summary To enhance the convergent rate and robustness of buck-type DC-DC converter system, a new finite-time voltage regulation control algorithm is proposed in this paper. First, an average state space-based model is analyzed, which considers both the parameters uncertainties and the variations of load and input voltage. By using saturation finite-time control theory, at the first step, in the absence of disturbance, a new fast voltage regulation control algorithm is designed, which can guarantee that the output voltage converges to the reference voltage in a finite time. Because the saturation constraint is considered during the controller design, the duty ratio function of the converter satisfies the constraint between 0 and 1. Second, in the presence of disturbance, a finite-time convergent disturbance observer is designed to estimate the unknown disturbances in a finite time. Finally, a disturbance observer-based finite-time voltage regulation control algorithm is developed. Compared with PI (Proportional-Integral) control algorithm, circuit simulations show that the proposed algorithm has a faster regulation performance and stronger robustness performance on disturbance rejection.