Control Scenarios for an SOFC System

This report is intended to summarize the work of a semester project conducted on a gPROMS model (developed in LENI) of an existing stand-alone 1kW solid oxide fuel cell (SOFC) system. Different means of controlling the cathode gas temperature with single-input-single-output PID controllers were investigated. Particular attention was directed to the issue of erroneous thermocouple readings due to radiation and how this error can be minimized. It was shown that the discrepancy between thermocouple reading and real temperature depends strongly on the method used to control the temperature. In some cases, the incorrect thermocouple reading can be fatal for the system even in regular operation. With this basic type of PID controller, lambda control was shown to be the scenario with the smallest discrepancy. However, it is still non-negligible and a more advanced control approach should be investigated before an implementation on the physical system.