Current-Limited Suboptimal Sliding Mode Control for Voltage-Regulated Synchronous Buck Converters

This article proposes a new sliding mode control based on a nonlinear switching surface that provides a suboptimal current-limited start-up response in step-down converters. The main idea behind the design consists in combining different switching surfaces. The first one forces the system trajectories to track a constant current path until the output voltage error is small. A nonsingular terminal switching surface then drives the trajectories to the vicinity of the steady-state operating point. Finally, a first-order switching surface regulates the steady state providing very good rates of load and line regulation. The article presents the design guidelines of the suboptimal sliding mode control and the experimental evaluation that confirms the effectiveness of the proposal.