This paper presents the derivation of a linear model with changeable parameters of constant frequency peak current mode controlled DC/DC boost converter supplied by a PEM fuel cell stack. The derived model has the same structure irrespective of the conduction mode and therefore, it is suitable for design of simple and advanced controllers of the output voltage. Experimental results on the system with 450W boost converter supplied by PEM fuel cell emulator show that the derived model accurately describes the system in a given operating point, determined by the load resistance or output current. (C) 2011 Elsevier B.V. All rights reserved.