Robust Output Voltage Regulation for DC–DC Buck Converters Under Load Variations via Sampled-Data Sensorless Control

The global robust output voltage regulation problem for dc-dc buck converter systems is investigated by means of designing a sampled-data almost disturbance decoupling (ADD) control methodology. Aiming to effectively restrain the output fluctuation caused by load variations, a physically realizable robust controller is proposed by employing a linear discrete-time observer to generate reliable state-reconstructed information under the conception of sensorless control. By virtue of output feedback domination approach, the proposed control strategy is able to achieve ADD, i.e., the output voltage interference can be arbitrarily attenuated in the L2 gain sense. To ensure the theoretical rationality of the proposed approach, rigorous stability analysis for the hybrid closed-loop system is provided. Moreover, both simulation and experimental results demonstrate the effectiveness of the proposed controller, and the regulating principle and robustness analysis of involved parameter selection are studied. The direct-designed digital compensator will facilitate the practical implementation in power electronic systems.