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Journal of Applied Mathematics
Volume 2013 (2013), Article ID 915146, 10 pages
Research Article

Sliding-Mode Control of a Dc/Dc Postfilter for Ripple Reduction and Efficiency Improvement in POL Applications

1Department of Electronics and Telecommunications, Instituto Tecnológico Metropolitano (ITM), Calle 54A No. 30-01, Medellín, Colombia
2Departamento de Energía Eléctrica y Automática, Universidad Nacional de Colombia, Carrera 80 No. 65-223, Medellín, Colombia

Received 28 June 2013; Revised 2 September 2013; Accepted 5 September 2013

Academic Editor: Dewei Li

Copyright © 2013 S. I. Serna-Garcés et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper proposes an active postfilter based on two Buck converters, connected in parallel, operating in complementary interleaving. In such a configuration the ripple in the load current could be virtually eliminated to improve the power quality in comparison with classical Point-Of-Load (POL) regulators based on a single Buck converter. The postfilter is designed to isolate the load from the main Buck regulator, leading to the proposed three-converter structure named BuckPS. The correct operation of the postfilter is ensured by means of a sliding-mode controller. Finally, the proposed solution significantly reduces the current harmonics injected into the load, and at the same time, it improves the overall electrical efficiency. Such characteristics are demonstrated by means of analytical results and illustrated using numerical results.