Current-Fed Full Bridge Converters for Fuel Cell Systems Connected to the Three Phase Grid

Fuel cells for low or medium power deliver comparatively low voltages compared to the mains voltage at high currents. A high dc-link voltage is needed to feed in electrical energy from fuel cells to the mains via a voltage source inverter. In the considered higher power range the full bridge dc-dc converter circuit is an appropriate solution. In this paper current fed full bridge converters with two types of regenerative clamping circuits as dc/dc converters for fuel cell inverter systems in the power range of 20 kW and higher are presented. The systems are analysed and compared to each other regarding their operating behaviour, their system complexity and semiconductor losses