Abstract
The PEMFCs systems are seen as a likely fuel cell choice
for the automotive applications. Automotive applications
lead to variable power operation. The architectures
typically adopted are load following or fuel cell-battery
hybrid systems. This article studies a control strategy
of the operating conditions for the variable power
configuration, typical in a load following applications.
In most of the existing applications, the operating
conditions are fixed to the nominal values. Typically,
the temperature is set to 70°C, the air stoichiometry
ratio is set to 2, the cell voltage is set to 0.6V,
operating at ambient pressure (1 atm). Fuel cells have a
wide power density range. At steady state conditions for
fixed operating variables it is possible to change the
produced power by changing the load current. The proposed
control strategy is obtained by numerical optimization.
The optimization process uses a zero dimensional fuel
cell mathematical model, taking into account also the
losses related to the air compressor system and the
balance of plant. The power loss in the intake air
compressor system is a critical factor because it can
reach values as high as 25% of the total stack power. The
numerical optimization is performed in order to maximize
the energy conversion efficiency at desired power density
by optimizing the operating conditions such as
temperature, pressure, air stoichiometry ratio and load
current. The optimization algorithm is an exhaustive
discrete optimal search. Each variable has a fixed range
and fixed number of values. Variables are i,?,T,p and
Power. For each set of operating points, voltage and the
stack power are computed. The power consumed by the air
compressor is subtracted from the stack power
subsequently. The optimization algorithm can also run in
on-line control scheme. The results of the optimization
process are curves that show values of the optimum
operating variables as a function of the net power. The
parameters of the fuel cell model correspond to the
characteristics of the GORE Primea Series. 56 MEAs. The
power of the fuel cell PEM stack corresponds to a 1 kW,
20 cells, 200cm2. The air compressor model corresponds to
the Thomas Industries, Inc., diaphragm pump, 2.4atm
gauge. The numerical optimization of the system and the
data management is performed using LabVIEWr by National
Instruments.
| Original language | English |
|---|---|
| Title of host publication | 1st European Fuel Cell Technology and Applications Conference (EFC2005) |
| Subtitle of host publication | Book of Abstracts |
| Publisher | American Society of Mechanical Engineers (ASME) |
| ISBN (Print) | 978-0-7918-4209-6 |
| Publication status | Published - 2005 |
| MoE publication type | Not Eligible |
| Event | 1st European Fuel Cell Technology and Applications Conference - Rome, Italy Duration: 14 Dec 2005 → 16 Dec 2005 Conference number: 1 |
Conference
| Conference | 1st European Fuel Cell Technology and Applications Conference |
|---|---|
| Abbreviated title | EFC |
| Country/Territory | Italy |
| City | Rome |
| Period | 14/12/05 → 16/12/05 |
