Optimized cabin power supply with a +/− 270 V DC grid on a modern aircraft

This paper deals with an onboard power supply of +/− 270 V DC (HVDC, high voltage DC). Conventional aircraft grids have a main voltage level of 115 V AC with a variable frequency of 360…800 Hz. In the future, fuel cells might replace the conventional auxiliary power unit (APU) to optimize the eco efficiency. With that technology HVDC-grids can be integrated in an aircraft. Changing to a HVDC-grid has a lot of advantages. Higher voltage means lower cable weight. Furthermore, the electrical converter architecture can be optimized. Especially the converters inside the loads can be build much lighter when using a +/− 270 V DC supply. This paper gives an overview of the electrical architecture on a modern short- and midrange aircraft and the effect of a +/− 270 V DC power grid thus focusing on the converter architecture in a modern aircraft. Concluding all benefits are summarized.