Boundary-Based PWM Control Scheme for a DC-DC Buck Converter Operating in CCM

Abstract

This paper presents a control scheme for DC-DC buck converters operating in Continuous Conduction Mode (CCM) that achieves fast and accurate regulation of the output voltage while reducing the computational burden on the control system. The study investigates the boundary-based control scheme for a buck converter and models the converter circuit as a Switched Dynamical System (SDS) using hybrid automaton due to its continuous and discrete states. The boundaries of these states are determined to enable the implementation of a fixed-frequency Pulse-Width Modulation (PWM) control scheme. The proposed control scheme was evaluated through simulation with variations in input voltage, load, and reference voltage. It was further analyzed for model mismatch due to parametric variations and parasitic parameters, which demonstrated its effectiveness and robustness under various operating conditions. The SDS approach for controlling the buck converter is simple, requires minimal mathematical calculations, and is free from modeling errors. The output voltage was stable under regulatory and servo problems, as well as sinusoidal input testing. The proposed scheme was compared with other conventional schemes and found superior in terms of steady-state and dynamic response. Additionally, integral compensation was introduced to counter parasitic parameters, which was found to be effective.