Fuel cell systems and control methods including a fuel cell and a second energy
source, such as a battery that is adapted to supplement the fuel cell. In addition,
the fuel cell system utilizes a single bipolar switching module, such as an IGBT
six pack module that is configured to implement a DC/DC converter, such as a DC/DC
boost converter, for both the fuel cell and the battery. The fuel cell system also
makes use of a controller that is configured to control either or both of input
current and output voltage of the DC/DC converter.