Solid oxide fuel cell system responsive to explosive vaporization of water in reformer to control power

A solid oxide fuel cell system for generating electrical power using reformed fuel reformed by adding steam to supplied fuel, comprising:

• a fuel cell module including a plurality of fuel cell units;
• a fuel supply device configured to supply fuel;
• a reforming chamber configured to react the fuel supplied from the fuel supply device with steam to reform the supplied fuel and supply the reformed fuel to the fuel cell module;
• a vaporization chamber disposed on the upstream side of the reforming chamber and configured to generate the steam therein and supply the generated steam to the reforming chamber;
• a water supply device configured to supply water to the vaporization chamber for vaporization of the water to generate the steam;
• a controller programmed to control the fuel supply device and the water supply device, and to control extraction of electric power from the fuel cell module, wherein the controller includes a bumping determination circuit and an extracted power limiting circuit,
• wherein the bumping determination circuit is programmed to determine an occurrence of excessive and sudden vaporization of water in the vaporization chamber, and
• wherein the extracted power limiting circuit is programmed to reduce extraction of the electrical power from the fuel cell module when the bumping determination circuit determines an occurrence of excessive and sudden vaporization of water in the vaporization chamber.