An electrical architecture for an aircraft having a main electrical machine connected to a fuel burning engine and a secondary electrical machine connected to a power transmission assembly. A high-voltage electrical master box is connected by a first line and by a second line to a multifunction converter, the high-voltage electrical master box connecting the first line to the secondary electrical machine, and the second line to at least the main electrical machine and the secondary electrical machine. The multifunction converter includes a supervisor connected to an avionics system and to a control system controlling the engine, and to a controller of the high-voltage electrical master box.