Hybrid Control of a Boost Converter Operating in Discontinuous Current Mode

Abstract

The control of DC-DC converters, in particular the boost converter, has been the focus of research for nearly 3 decades. Several attempts have been made to design a suitable controller for the boost converter. But these designs either suffer from model inaccuracy or their inability to apply to both continuous and discontinuous current modes (CCM and DCM). In this paper, a hybrid control scheme, based on hybrid automaton, is proposed for the output voltage regulation of a boost converter. Though the emphasis in this paper is on DCM, the scheme is applicable to both CCM and DCM operation. A safe area around the operating point is determined in the state space to ensure the stability of inter-mode switching. The safe area and the steady state set point are dynamic in the sense that they vary under various line and load disturbance conditions. Then, a suitably designed control algorithm prevents the system states from moving outside the safe area. Different load and input voltage disturbance conditions are simulated in MATLAB/SIMULINK and the results are presented to demonstrate the suitability of the controller. The transient and steady state performance of the closed loop control is found to be satisfactory.