Analysis and Design of a Controller for an Input-Saturated DC–DC Buck Power Converter

Octavio Garcia-Alarcon,Javier Moreno-Valenzuela

doi:10.1109/access.2019.2912858

Octavio Garcia-Alarcon, Javier Moreno-Valenzuela

Open Access

https://doi.org/10.1109/access.2019.2912858

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Abstract

In this paper, a novel controller for an input-saturated direct current to direct current (DC–DC) buck power converter has been proposed. The control scheme guarantees global asymptotic stability, even though the input to the power converter is affected by a hard saturation nonlinearity that results from the fact that in practice the duty cycle can only take continuous values between zero and one. Specifically, asymptotic stability is ensured by using a special quadratic-type Lyapunov function and LaSalle’s invariance principle. In addition, to prevent inductor current’s noisy measurements, an observer is proposed together with the proposed control law. Stability is also discussed rigorously for the resulting observer-based scheme. The real-time experimental comparisons with respect to a known approach are presented. Better performance is obtained with the novel observer-based controller.

Highlights

Most applications that require regulation of direct current to direct current (DC-DC) use a switched power converter [1]
The goal of this work is to achieve stability of the system given the constrained input of the DC-DC buck power converter
A controller deserving much attention is the one reported by El Fadil et al [35], which can conduct an output voltage regulation under the assumption that the system is affected by the input saturation μ(t) in (3)

Summary

Introduction

Most applications that require regulation of direct current to direct current (DC-DC) use a switched power converter [1]. The control action can be out of the physically admissible limits in that the PWM signal is produced. This is usually not considered for the design and closed-loop system analyses of the control system [4]. Saturation input is one of the most common non-linearities in physical systems and is rarely considered in the analysis and design of controllers for power converters because the complexity of the stability analysis of the closed loop system [5]

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