Patent ID: 7087327

Claim:
An electric power plant comprising: a power supply system, the power supply system comprising: a power bus, a first and second fuel cell system, each fuel cell system comprising a fuel cell stack, an electrical power storage device electrically coupled in parallel with the fuel cell stack, and means for controlling a flow of current from the fuel cell stack to the electrical power storage device and the power bus, a first switch selectively operable to electrically couple the first fuel cell system in series in the power bus, and a second switch selectively operable to electrically couple the second fuel cell system in series in the power bus; an oxidant supply system for supplying an oxidant gas to at least one of the fuel cell stacks; and a fuel supply system for supplying a fuel gas to at least one of the fuel cell stacks, wherein the first switch is selectively operable according to an operating condition of the first fuel cell system, and wherein the power supply system further comprises a first redundancy switch electrically coupled in series with the first switch and selectively operable therewith to electrically couple the first fuel cell system in series to the power bus, the first redundancy switch being selectively operable according to at least one of the operating condition of at least the second fuel cell system, a voltage across the power bus, a desired output of the power supply system and a desired nominal current output of the power supply system.