LAUSR

This article proposes a second-order sliding mode control law, based on a super twisting algorithm (STA), aimed at regulating the output voltage of a dc–dc buck converter. A closed-loop system is designed consisting of two distinct nested loops organized within a cascaded STA structure. Several sliding mode control algorithms are here surveyed for the regulation of a dc–dc buck converter. The STA of second-order sliding mode is also experimented in an HIL system. The comparative evaluations include comparing the output voltage transient responses to load step changes for all developed sliding mode control algorithms and the start-up responses of the output voltage to step changes of the input voltage of the buck converter. Furthermore, theoretical considerations, numerical simulations, and experimental results from a laboratory prototype are compared, at different operating points, for all surveyed control methods. It results from the simulations and experiments that the designed STA achieves the fastest convergence, a consistent chattering reduction, the smallest settling time under loaded situations, and small steady-state error during load changes over all contrasted control methods.