Comparison of different electrical HVDC-architectures for aircraft application

Abstract

This paper deals with an integration of High Voltage DC (HVDC1) in the onboard power supply system. Conventional aircraft grids have a main voltage of 115 V AC (star voltage) with a variable frequency of 360…800 Hz. Newer aircraft try to integrate 230 V AC generators in the grid to save cable weight. With the “More Electric Aircraft”- concept HVDC grids could be integrated in future airplanes. In all concepts the airport infrastructure has to be considered. The ground power supply is based on mobile Ground Power Units (GPUs) or an inverter supplied by the airport grid (Fig. 1). The ground supply allocates 115 V AC with a fixed frequency of 400 Hz and a maximum power of 90 kVA per unit. Changing to an 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 built much lighter when using a DC supply. This paper compares different possibilities of HVDC integration. Ancillary conditions like carbon fiber reinforced plastic fuselages and a possible ground power supply with conventional technology are taken into consideration. The attention is focused on an efficient cabin power supply. But to make a global assessment, the entire onboard power supply system is analyzed.