Title: Bond graph models of DC-DC converters operating for both CCM and DCM

Authors: Antonios Markakis; William Holderbaum; Ben Potter

Addresses: Department of Cybernetics, School of Systems Engineering, University of Reading, Reading, Berkshire, UK ' Department of Cybernetics, School of Systems Engineering, University of Reading, Reading, Berkshire, UK ' Department of Cybernetics, School of Systems Engineering, University of Reading, Reading, Berkshire, UK

Abstract: In this paper, bond graphs are employed to develop a novel mathematical model of conventional switched-mode DC-DC converters valid for both continuous and discontinuous conduction modes. A unique causality bond graph model of hybrid models is suggested with the operation of the switch and the diode to be represented by a modulated transformer with a binary input and a resistor with fixed conductance causality. The operation of the diode is controlled using an if-then function within the model. The extracted hybrid model is implemented on a boost and buck converter with their operations to change from CCM to DCM and to return to CCM. The vector fields of the models show validity in a wide operational area and comparison with the simulation of the converters using PSPICE reveals high accuracy of the proposed model, with the normalised root means square error and the maximum absolute error remaining adequately low. The model is also experimentally tested on a buck topology.

Keywords: switching mode power converters; bond graphs; hybrid models; diode model; buck topology; boost; CCM; continuous conduction mode; DCM; discontinuous conduction mode; simulation; mathematical modelling.

DOI: 10.1504/IJPELEC.2014.060706

International Journal of Power Electronics, 2014 Vol.6 No.1, pp.18 - 41

Received: 15 Aug 2013
Accepted: 06 Mar 2014

Published online: 23 Oct 2014 *

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