This paper presents a sliding-mode control design of a boost–buck switching converter for a voltage step-up dc–ac conversion without the use of any transformer. This approach combines the step-up/step-down conversion ratio capability of the converter with the robustness properties of sliding-mode control. The proposed control strategy is based on the design of two slidingcontrol laws, one ensuring the control of a full-bridge buck converter for proper dc–ac conversion, and the other one the control a boost converter for guaranteeing a global dc-to-ac voltage step-up ratio. A set of design criteria and a complete design procedure of the sliding-control laws are derived from small-signal analysis and large-signal considerations. The experimental results presented in the paper evidence both the achievement of step-up dc–ac conversion with good accuracy and robustness in front of input voltage and load perturbations, thus validating the proposed approach.

Peer Reviewed