Fuel cell Voltage Monitoring system

A security system for a stackable fuel cell, with which 40 cell voltages, at the most, can be measured.

Working
For experiments, carried out with fuel cells (stacks), it is necessary to measure all cell voltages; in case one of the cell voltages decreases below a certain level, the supervisory system has to be able to intervene, based on this information. In case one of the cell voltages gets too low, two 'relais' exits will be de-activated (= open circuit). Depending on the setpoint of two, in advance, tuned tension values, either the 'warning' exit or the 'fatal' exit will be activated. By this, the cell or stack can be switched off or disconnected from the electrical load (ofcourse through a therefore suitable powerswitch).

Stackable fuel cells
Because the total voltage over a stack (existing of, for example, 400 cells) can rise up to approximately 400 Volt DC and higher, the design of the VMS must be resistant to this voltage difference. The system is designed in such way, that it is suitable for small (1-40 cells) as well as large stacks (1-400 cells).

Interfaces
The board is standard equipped with a CAN 2.0B-interface. In order to relieve the CAN-communication network, it is possible to, by choice, either send all measurement values, or just the lowest values and cellnumber through the CAN-controller(s) and the CAN-network to the supervisory system.

On the VMS-board, a DIP-switch is installed to set the base-addresses of the CAN-system.

At the front side, the cell voltages must be connected. Also, there are warning lights and a RS232 monitor at the front side.