Overcurrent Protection Control Design for DC-DC Buck Converter With Disturbances

This paper deals with the output voltage regulation problem for dc-dc buck converters. Overcurrent protection and disturbances are both taken into consideration. The main challenge of control design is how to ensure that the current constraints are not violated at any time in the presence of disturbances. At first, a high-gain disturbance observer is utilized to estimate the disturbances. Then, a novel punishment mechanism for the inductor current is designed in the control scheme. Finally, based on the novel current-constrained technique and the high-gain disturbance observer, a composite control approach is proposed. The new control method not only guarantees the current within the required range but also has a nice ability on the disturbance rejection. In the meantime, rigorous stability proof is also presented. The theoretical analysis also explains how disturbances affect the satisfaction of the current constraints. The experimental results on a buck converter system are illustrated to verify the feasibility and effectiveness of the proposed control scheme.