Constrained Nonlinear Control of Buck-Boost DC-DC Power Converter with Continuous Input Current for Fuel Cell Energy Conversion

Abstract

This classical DC-DC buck-boost converter topology drains a pulsating current from the input power source. Using this converter for interfacing with a fuel cell could accelerate the aging rate of the fuel cell. In this paper, a dc-dc buck-boost converter with continuous input is investigated. In addition to its input current, the converter offers the advantage of using a reduced number of electronic components. The objective is to elaborate on a controller that achieves a dc-bus voltage regulation despite the load resistance uncertainty. The point is that the converter presents a no-minimum feature, and the duty ratio should be confined between 0 and 1. Then, a saturated nonlinear controller is elaborated. The advantage of the proposed control strategy lies in its simplicity compared to the existing nonlinear approaches. Detailed analysis and simulation show that the proposed controller meets all the control objectives, namely tight dc-bus voltage regulation and asymptotic stability of the closed-loop system. Experimental results, which show the effectiveness of the controller, are also given.