Fuel
Cell Power Controllers
Power Supplies
for Fuel Cells (Application Notes)
 Fuel
Cells are similar to solar panels in that they exhibit a
VI curve where the voltage decreases with increasing output
current. Adapting a switch mode DC-DC converter to work
with a fuel cell is similar to a solar panel. To prevent
the converter from drawing too much current from the fuel
cell and 'locking' it down to an un-useable voltage level,
Analytic Systems uses a 'discontinuous operating mode' once
the output voltage from the fuel cell falls below the optimum
operating voltage. Once the load on the converter is reduced
so that the fuel cell voltage recovers, the converter resumes
a normal continuous mode of operation. As this is a normal
mode of operation for the converter, the audible alarm is
disabled for the low input voltage condition, although the
low input LED will still light to show when the converter
is running in discontinuous mode.
If
the peak load exceeds the maximum power output of the fuel
cell, then a battery should be added to the system to handle
the peak currents, and the converter should be built as a
DC-DC battery charger.
Fuel
Cell Converter Product Descriptions
The
type of converter to be used with the fuel cell varies depending
on the voltage required by the load and the range of voltages
available from the cell. If the voltage from the cell is always
greater than required by the load, then a simpler step-down
or 'buck' converter such as the VTC300 or VTC600 can be used.
Conversely, if the load voltage is always greater that the
output voltage of the cell then a step-up or 'boost' converter
such as the VTC305 or VTC605 can be used. All of these converters
are 'common negative'.
If
the voltage required by the load is both greater and less
than the fuel cell output voltage (i.e. The fuel cell voltage
ranges from 40 to 60 VDC, and the load is 48 VDC) then we
recommend a fully isolated converter such as the VTC315, VTC615
or VTC1015. We also recommend these converters if full electrical
isolation is required between the fuel cell and the load.
If
the fuel cell is being used to charge a battery, then simply
changing the first 3 digits of the part number from VTC to
BCD will add the necessary components for battery charging.
We
can build converters for load voltages from 1.5 to 48 VDC,
fuel cell voltages from 12 to 300 VDC, and power levels from
60 to 1500 watts.
Please
contact our Engineering Support team
if your application is for operation with a fuel cell. Provide
a VI graph if possible to allow us to tailor the converter
exactly to your requirements. We will advise on the extra
charges (usually minimal) to adapt one of our converters to
your exact requirements.
To Download the PDF Version of this report please click <HERE>
To View Our NASA Fuel Cell Case Study please click <HERE>
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