Robust control of a single-ended primary-inductor converter (SEPIC)

Abstract

This paper approaches the topic of robust control for DC-DC power converters. A low-power single-ended primary-inductor converter (SEPIC) has been chosen as a case study, for which the output voltage regulation problem in presence of parameter uncertainties is stated in the Hinf formalism as a disturbance-rejection problem. This approach is assessed by numerical simulations in MATLAB against a classical integral state-feedback control from the point of view of robustness in stability and in performance, when two parameters — input voltage and load resistance — vary, but are bounded within known ranges. Comparison shows that Hinf control design, provided that it handles more degrees of freedom, can offer more detailed information about robustness ranges, but this advantage has to be weighed against its complexity compared to state-feedback control. Choice of some either classical or robust control solution depends upon requirements and constraints of each application.