Power source assembly for an aeronautical vehicle

A power source assembly for an aeronautical vehicle, the power source assembly comprising:

• a fuel cell module configured to provide a first direct current (DC) power output;
• a battery module configured to provide a second direct current power output;
• a direct current electric bus configured to provide a net direct current power output to a load;
• a DC/DC converter in electrical connection with the direct current electric bus, the DC/DC converter configured to receive the first direct current power output from the fuel cell module or the second direct current power output from the battery module;
• and
• a controller operably coupled to the DC/DC converter and configured to receive data indicative of the first direct current power output, the controller configured to control the DC/DC converter based on the data indicative of the first direct current power output to maintain a slew rate from the fuel cell module within a slew rate range for the fuel cell module.