POWER SUPPLY SYSTEM FOR ELECTRIC VEHICLE

A power supply system disclosed herein may include: a first voltage sensor measuring voltage of a main power source; a power converter connected to a main power source through a relay; a voltage converter; and a controller. The power converter includes a capacitor connected to the main power source and a second voltage sensor measuring voltage of the capacitor. The controller precharges the capacitor with the voltage converter before closing the relay. The controller may be configured to: set target voltage by a measurement value of the first voltage sensor; acquire the measurement value of the first voltage sensor again as verification voltage when a difference between the target voltage and control voltage which is a measurement value measured by the third voltage sensor has fallen within a predetermined tolerance; and close the relay if a difference between the control voltage and the verification voltage is within the tolerance.