Power conversion system for vehicles and control method thereof

A power conversion system for vehicles included in a vehicle, comprising:

• a switching circuit including first input/output terminals, second input/output terminals, and a plurality of switching elements connected between the first input/output terminals and the second input/output terminals, wherein the switching circuit is a bi-directional alternating current/direct current (AC/DC) converter;
• a first energy storage device connected to the second input/output terminals and having a preset charging/discharging voltage;
• a first voltage conversion circuit for converting power output from the first input/output terminals to output a voltage less than the voltage of the first energy storage device;
• a second energy storage device charged/discharged with the output voltage of the first voltage conversion circuit;
• and
• a controller configured to control open/short-circuit states of the plurality of switching elements based on whether the first energy storage device is being charged and whether the vehicle is being driven,
• wherein when the first energy storage device is being charged, then alternating current (AC) charging power for charging the first energy storage device is provided to the first input/output terminals from outside of the vehicle, and
• wherein the first input/output terminals are connected to a charging port to receive the AC charging power from the outside.