Adaptive voltage regulation and equal current distribution of parallel-buck DC-DC converters using backstepping sliding mode control

This paper develops a novel methodology for voltage regulation and equal current distribution of parallel-buck DC-DC converters. Such converters are modeled as linear averaged state-space system models with adjustable loads. Two measurements, such as output voltage and inductor current, are used to accomplish the design of an adaptive backstepping sliding mode controller for the parallel-buck DC-DC converters. Based on the singular perturbation method, a reduced order model is derived in order to show that the effect of equivalent series resistance (ESR) of the capacitor can be ignored and the parallel converters can be well approximated by the reduced order model. With the reduced order model, an adaptive sliding mode control utilizing backstepping approach is proposed to control the parallel-buck DC-DC converters. This proposed control method has been verified by computer simulations, and has also been proven capable of giving satisfactory voltage regulation performance under input voltage variations and load changes.