DC power supply and control method thereof

The invention relates to a DC power supply and a control method thereof. The direct-current power supply comprises a direct-current power circuit, a plurality of direct-current/direct-current conversion circuits, a plurality of electric energy output ports and a voltage control circuit. The direct-current power circuit is used for generating bus power. Each DC/DC conversion circuit is used for converting a bus power supply into a corresponding output port power supply and outputting a corresponding output voltage from a corresponding electric energy output port. The voltage control circuit sets a selected bus voltage according to the required voltage of each electric energy output port, and adjusts the voltage of the bus power supply to the selected bus voltage. And when any output voltage is smaller than the corresponding required voltage, the voltage control circuit increases the default value-added voltage to the selected bus voltage until each output voltage meets the corresponding required voltage. 本发明涉及