  The integration of a solid oxide electrolysis cell (SOEC) with a photovoltaic
(PV) system presents a viable method for storing variable solar energy through
the production of green hydrogen. To ensure the SOEC's safety and longevity
amidst dramatic fluctuations in solar power, control strategies are needed to
limit the temperature gradients and rates of temperature change within the
SOEC. Recognizing that the reactant supply influences the current, a novel
control strategy is developed to modulate heat generation in the SOEC by
adjusting the fuel flow rate. The effectiveness of this strategy is assessed
through numerical simulations conducted on a coupled PV-SOEC system using
actual solar irradiance data, recorded at two-second intervals, to account for
rapid changes in solar exposure. The results indicate that conventional control
strategies, which increase airflow rates, are inadequate in effectively
suppressing the rate of temperature variation in scenarios of drastic solar
power changes. In contrast, our proposed strategy demonstrates successful
management of the SOEC's heat generation, thereby reducing the temperature
gradient and rate of variation within the SOEC to below 5 K/cm and 1 K/min,
respectively.
