Kreutzer, O.O.KreutzerEckardt, B.B.EckardtMärz, M.M.März2022-03-122022-03-122014https://publica.fraunhofer.de/handle/publica/38799310.1109/EPE.2014.6910797This paper describes the power stage of a non-isolated unidirectional 400 V 100 kW DCDC converter for fuel cell vehicles that reaches a switching frequency of 150 kHz with industry power modules. The power modules are equipped with custom made DCB-substrates assembled with a combination of fast 600 V super-junction Si-Mosfets and SiC-Schottky Diodes. For all other components like drivers, current sensors and the auxiliary supply converter standard products have been used to facilitate an automotive specification, and a cost efficient production. The inductors are custom-made to reduce choke losses and volume. The converter reaches an efficiency of 98 % at full load (166->400 V, 590 A lowside current). Furthermore a simple and reliable DC-link discharge unit is described that discharges with constant power and is far smaller and faster than a conventional resistor solution. Based on a constant current discharge device using a Power MOSFET in linear operation, it is extended with a small analog circuit to a roughly constant power discharge device.enconference paper