This example shows a model of a solid oxide fuel cell (SOFC) which can be utilized in Specialized Power Systems.
The system consists of a SOFC which is connected to a three-phase infinite bus through an IGBT inverter. The inverter uses hysteresis switching and controls active power by manipulation of direct-axis current while holding reactive power at 0VAr.
The measurement blocks are rated at 50kW. Therefore, an active power reference of 1pu = 50kW.
Start the simulation.
At t = 0s, an active power reference (Pref) of 0.3pu is commanded. Observe that the reference is captured within 0.2s.
At t = 0.4s, Pref = 1pu is commanded. Again, the reference is captured within 0.2s.
Observation of the H2, H20 and O2 pressures shows that the fuel cell does not reach a new equilibrium for the simulation of duration 1 second. Extended simulation periods are required to observe the dynamics of the chemical reaction.
This model assumes the following:
The fuel cell gases are ideal
Only one pressure is defined in the interior of the electrodes
The fuel cell temperature is invariant
Nernst's equation applies.
The model is taken from:
Y. Zhu and K. Tomsovic, 'Development of models for analyzing the load-following performance of microturbines and fuel cells', Electric Power Systems Research, 62, 2002, 1-11.