Non-isolating DC/DC converter for a fuel cell powered aircraft

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.