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SIZING OF A STAND-ALONE PEM FUEL CELL POWER SYSTEM PART I: LOAD DATA ANALYSIS, DESIGN SPECIFICATIONS AND FUEL CELL DESIGN


MARIAN GAICEANU
“DUNAREA DE JOS” UNIVERSITY OF GALAŢI,

Issue:

MOCM, Number 14, Volume I

Section:

Issue No. 14 - Volume I (2008)

Abstract:

This paper intends to be a real useful tool into designing the fuel cell power systems for stationary applications. A complete methodology, sustained with a certain system example is shown. This tool can calculate the necessary power for the overall system, followed by the design of each fuel cell power system’s component having the maximum load power as main data input. Because the changes in the electrical load are faster than in the fuel cell process, the storage elements are necessary. In order to design the storage elements of the system, the real ac and dc load profiles of a certain application have been used. The single phase inverter, 220Vac, 50Hz in stand-alone operating mode has been established through an adequate analysis of the load profiles. The fuel cell stack voltage, Vfc, has 48Vdc, as nominal value. The dc bus voltage level (48Vdc) was chosen by taking into account the fuel cells manufactures. Therefore, the voltage level must be increased to 220Vac. Moreover, the galvanic isolation is required. The isolation aspect is covered by using an adequate push-pull converter. In this way the voltage level is increased to 400Vdc. The second energy conversion is mandatory. By using a half bridge inverter topology, the 220 Vac-50Hz desired voltage level is obtained. The hydrogen necessary for the proton exchange membrane (PEM) fuel cell stack is obtained from the reformer. The fuel cell polarization curve has been modeled by using the Amphlett model. In order to charge the battery pack, a bidirectional half-bridge dc-dc converter has been used. The main requirement in sizing of the battery stack is to support accordingly the start-up of the fuel cell stack. In the same time, the battery must support the auxiliary system consumption in order to supply the fuel cell during operation. The detailed energy analysis, the components sizing and output results from this tool are presented.

Keywords:

PEM, stand-alone, dc-dc converter, inverter, load profile, stack, battery.

Code [ID]:

MOCM200814V01S01A0013 [0001864]


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