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

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.

Keywords

• Buck power converter
• input saturation
• Lyapunov’s stability
• observer-based controller
• real-time experiments