Bidirectional powering on-board charger, vehicle power supply sysem including the same, and control method thereof

A vehicle power supply system, comprising:

• a main battery;
• an on-board charger (OBC) having a first input/output terminal connected to electric vehicle service equipment (EVSE) and a second input/output terminal connected to the main battery, in which alternating current (AC) power input to the first input/output terminal is converted into direct current (DC) power to be output to the second input/output terminal, and a magnitude of the DC power input to the second input/output terminal is converted and output to the first input/output terminal;
• a lower voltage DC-DC converter (LDC) in which a DC voltage is input from the main battery and the input DC voltage is converted into a low voltage to be supplied to an auxiliary battery or an electronic load of a vehicle;
• a switching unit connected between the first input/output terminal and the LDC;
• and
• a controller configured to adjust a powering direction of the OBC and an on/off state of the switching unit, based on whether the main battery is charged by the OBC and whether the LDC fails.

A method of controlling a vehicle power supply system, comprising:

• determining, by a controller, whether a low voltage direct current-direct current converter (LDC) of a vehicle fails;
• electrically connecting, by the controller a first input/output terminal of an on-board charger (OBC) and an output terminal of the LDC when the LDC is determined to fail, the OBC having the first input/output terminal connected to electric vehicle service equipment (EVSE) and a second input/output terminal connected to a main battery of the vehicle, and alternating current (AC) power input to the first input/output terminal is converted into direct current (DC) power to be output to the second input/output terminal, and a magnitude of the DC power input to the second input/output terminal is converted and output to the first input/output terminal;
• and
• operating, by the controller, the OBC to convert power for charging the main battery and output to the first input/output terminal by the OBC.