Event-Triggered Control for Safety-Critical Buck DC-DC Converters Using Robust Barrier Lyapunov Functions

This article presents a robust event-triggered voltage regulation strategy for DC-DC converters that address both state constraints and disturbances. Conventional barrier Lyapunov functions (BLFs) may face limitations in handling transient constraint violations caused by external disturbances or abrupt reference changes and can lead to potential control singularities. To overcome this, we propose a novel robust BLF (RBLF) integrated with a dynamic safety boundary (DSB). The DSB adaptively adjusts based on the tracking error, enabling the RBLF-based controller to manage large state deviations and robustly guide the system back into the specified safe set with bounded control inputs. This approach effectively prevents singularities and offers resilient safety. To enhance resource efficiency, an RBLF-based event-triggered controller is developed within the backstepping framework. This controller specifically addresses the discontinuity and nondifferentiability of the virtual control law under event-triggered sampling by leveraging its partial derivatives and sampled states. Theoretical analysis confirms closed-loop signal boundedness, uniform ultimate boundedness (UUB) of the system, and Zeno-free operation. Experimental results demonstrate stable voltage regulation, robust performance under multiple disturbances, and a substantial reduction in control updates.