Power supply system with prioritised network selection

The system (10) has a set of controllable energy transfer units (T1-TN), where each of the energy transfer unit is connected to a set of power supply networks (R1-RN). An energy converter (16) is connected to an output of the set of controllable energy transfer units. The energy transfer units are utilized for selection of a power source from the set of power supply networks. A control unit (14) is utilized for controlling the energy transfer units for selection of the power source as a function of input voltages (V1-VN) and storage voltage (Ve).