On Control of a Boost DC-DC Power Converter under Constrained Input

Received Jul 30, 2016; Revised Nov 14, 2016; Accepted Dec 6, 2016

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1. Introduction

The voltage of many electrical and electronic systems is often higher than the voltage of the main source, for example, in systems powered by batteries. A conventional solution employs the so called boost DC-DC (direct current to direct current) converter where the increase of the output voltage is accomplished. Textbooks giving introduction to the history, construction, and control of the boost power converters are [1–4].

The boost power converter is applied in photovoltaic systems [5], mobile communication circuits [6], power factor correction [7], and hybrid electric vehicle systems [8]. This power converter is a bilinear second order nonminimum phase system and under certain operation conditions can be affected by disturbances and other nonlinearities.

The perspective in power electronics engineering to control a boost power converter relies on the characterization of the devices and in the design of compensation circuits. On the other hand, in control engineering, the approach to regulate the output voltage is to modify the duty cycle, thus compensating the losses due to the operation of the components.

In order to provide a degree of robustness to compensate uncertainties in the load, supply voltage, and unmodeled disturbances, many control algorithms have been devised to achieve voltage output regulation; see, for example, [9–12]. More recently, the work in [13] presented a comparison of nonlinear controllers for the DC-DC boost power converter. In [14], the problem of output feedback regulation via Lyapunov’s theory was addressed.

Usually, the duty cycle percentage is the control input for the boost power converter. This a number that is into the set $[\mathrm{0,1})$ and this constraint is rarely taken into account to design a control system. The reason probably is the increasing in the complexity of the closed-loop system stability analysis. As pointed out in the textbook [15, p. 171]: “saturation is probably the most commonly encountered nonlinearity in control engineering.”

Works considering saturation of duty cycle in control input for buck converters can be found in [16, 17]. Specifically, the research in [16]...

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