Design and Experimental Validation of an Embedded Sliding Mode Controller for Voltage Regulation With SEPIC Converters

This paper addresses the challenge of regulating the output voltage in single-end primary inductor converters (SEPICs) and introduces a practical solution based on the generation of second-order suboptimal sliding modes (2-SOSM). In contrast to the common assumption of a lossless SEPIC, in this paper, a lossy SEPIC is explored. A concise mathematical representation of its model is presented, and the equilibrium point is explicitly defined. Using only the output voltage as a measurement, it is proven that the proposed 2-SOSM strategy achieves finite-time convergence of the output voltage with its reference. The proposed method effectively handles saturation constraints on the control variable, ensuring that the SEPIC duty ratio remains between 0 and 1. Furthermore, the approach proves to be robust to variations in the load resistor. The experimental analysis validates the effectiveness of our proposal and highlights its practical benefits. A comparison with a standard proportional integral control (PI) on an embedded platform underscores the superiority of the adopted approach.