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Fuel cells in aircraft applications are gaining more and more interest because of higher possible efficiency and increasing air pollution standards. A necessary supplement is an efficient, lightweight and reliable DC/DC-converter to adjust the weak fuel cell characteristic to the voltage level of buffer batteries and drive inverters. Cosmic radiation, condensation, strict EMI-limits and significantly increased creepage distances impair a light and efficient converter. This paper explains approaches to solve those technical difficulties, especially a way to fulfill EMI standards without a large and heavy EMI-filter and introduces the first converter's application, a fuel cell powered UAV. The converter is developed with a strictly scalable design. Therefore an up-rating to multi megawatt applications for larger aircraft is discussed and possible occurring challenges are evaluated

SiC-MOSFETs are available since several years, but unlike SiC diodes they have not arrived in the mass market yet. The main reason is that the higher costs do not get compensated by the technical advantages in common applications. This lack is not only caused by the SiC-MOSFETs itself, but also by the packaging and the gate drivers. Consequently the main challenge for getting SiC-MOSFETs to a wider acceptance by application engineers is to show how all benefits of the new technology can be used. This paper demonstrates how SiC-MOSFETs can be operated in a standard half bridge application with exceptional switching speeds of less than 4 ns, resulting in slopes of more than 200 kV/μs and lowest possible switching losses. Previous publications have claimed to use “the full potential of the SiC devices for power conversion applications” achieving switching times of 20 ns [1].