Environmental Engineering Reference
In-Depth Information
a
Electric Brake
DC/DC
Controlled
Converter
AIR
M
FUEL CELLS
SYSTEM
INVERTER
Electric Drive
AUXILIARY MANAGEMENT
H
2
BATTERY
P
AC
K
MONITORING SYSTEM
b
S1
A
A
+
+
V
V
-
-
A
S2
BATTERY
PACK
Fig. 6.2 a Overall scheme of fuel cell power train on test bench. b Electrical connections
between stack, batteries, and load with location of sensors
Figure
6.2
a shows the scheme of the integrated fuel cell power train as installed
on the laboratory test bench, whereas Fig.
6.2
b shows the electric connections
between the stack, storage system and electric drive. In particular, the stack
electric outputs are connected to the DC-DC converter, whose function is to raise
the stack output voltage to the value required by the battery pack and electric drive
connected in electric parallel. The energy flow is unidirectional from stack toward
DC bus, while the battery pack can be recharged by both stack and engine (during
regenerative braking) as well as discharged when the energy required from the
engine is higher than the energy provided by the fuel cell system. Current and
voltage transducers are used for monitoring the main power flows between the
components of the system. Furthermore, some security switches are installed in
case of unpredictable events which require the instantaneous disconnection of the
battery pack and/or stack from the other parts of the system to avoid any damage.
