The topologies that are compared in this paper vary in the number of DC/DC-converters. In the single-converter topology, the traction drive is directly connected to the fuel cell whereas the battery is connected to the common link by a DC/DC-converter. In the dual-converter topology, the battery as well as the fuel cell is both connected to the dc-link by a DC/DC-converter. This permits the control of a constant, to the operating point adjusted, dc-link voltage and considerable cost savings are predicted for the manufacturing of the fuel cell stack. To attain this feature, a higher power electronic complexity and additional losses in the fuel cell converter have to be accepted. Despite the vehicle costs, the questions will be answered in this paper how the efficiency of the electrical drive train will be influenced by a variable dc-link voltage and with which topology the maximum efficiency can be reached in a drive cycle.