Experimental Characterization of an Autonomous Power Unit Equipped with a PEM Fuel Cell

SUMMARY The paper presents a developed test facility, equipped with a Digital Signal Processor (DSP), for the experimental characterization of an autonomous Auxiliary Power Unit (APU), which is based on a Proton Exchange Membrane (PEM) fuel cell and a set of electrochemical batteries, both connected to a common AC bus through power electronic converters. The paper also describes a steady state model for the simulation of the APU; the model is specifically tuned for a 4.8 kW commercial PEM fuel cell by means of experimental data acquired by the test facility. 1 INTRODUCTION Proton Exchange Membrane (PEM) fuel cells are potentially suitable for the application in autonomous Auxiliary Power Unit (APU) and various schemes of fuel cell/battery power sources have been recently investigated [1-13]. In a previous study of the authors [14], a preliminary procedure for the sizing of the APU components and for a first identification of the operation rules of the fuel cell (FC), taking into account the stochastic nature of load demands has been presented. This paper is devoted to the description of a test facility, developed, at the DIEM Laboratories of the University of Bologna, for the experimental characterization of an APU for on-board applications, composed of a commercial grid-connected PEMFC and a battery. Both fuel cell and battery are connected to a common AC bus through power electronic converters. Moreover, the paper describes an empirical steady state model developed to reproduce and monitor the FC operation and to evaluate the FC system performances. The model could be used for the system components optimization, for example if a fuel cell unit is given, while the main auxiliaries are to be established in order to maximize the system electric efficiency. The outline of the proposed paper is the following: Section 2 briefly describes the considered APU and section 3 describes the experimentally developed test facility with the implemented sensors and DSP system features. Section 4 shows the characteristics of the conceived fuel cell model, highlighting the experimental data acquired with the test facility and required by the model.