Linear Identification and Model Adjustment of a PEM Fuel Cell Stack

KUNUSCH, CRISTIAN; HUSAR, ATILA; PULESTON, PABLO FEDERICO; MAYOSKY, MIGUEL ÁNGEL; MORÉ, JERÓNIMO JOSÉ

Posadas, Pcia. Misiones, Argentina

Congreso; Hidrógeno y Fuentes Sustentables de Energía (HYFUSEN); 2007

Instituto de Energía y Desarrollo Sustentable - Comisión Nacional de Energía Atómica (CNEA)

From the dynamic modeling point of view, the fuel cell stack represent a major challenge because their associated subsystems reveal complex dynamics. For instance, the cathode subsystem model of a classical hydrogen-oxygen feed stack is described by a fifth order nonlinear model. In many cases, the states interaction is usually modeled through several look-up tables, decision blocks and piecewise continuous functions. Many internal variables are inaccessible for measuring and cannot be used in control algorithms. To make significant contributions in this area, it is necessary to develop reliable models for control and design purposes. Thus, in the present paper, a dynamic linear model of a 7-cell stack is obtained through experimental data. The procedure followed to obtain a linear model of the considered system, in a specific operating point, consisted of performing spectroscopy tests of the four different single-input single-output subsystems. The considered inputs for the tests were the stack current and the cathode oxygen flow rate, while the measured outputs were the stack voltage and the cathode total pressure. Different linear models were fitted to the data in order to develop a complete representative model.