Apparatus and method for controlling LDC in electric vehicle

An apparatus for controlling a direct current-direct current (DC-DC) converter in an electric vehicle, comprising:

• a first controller configured to determine an initial command voltage of the DC-DC converter;
• a second controller configured to determine a compensation voltage allowing the initial command voltage to correspond to a terminal voltage of an auxiliary battery;
• a third controller configured to generate a first output voltage that corresponds to a charging current limit of the auxiliary battery;
• a fourth controller configured to generate a second output voltage that corresponds to an output current limit of the DC-DC converter;
• and
• a command voltage determiner configured to determine a first final command voltage of the DC-DC converter based on the initial command voltage from the first controller, the compensation voltage from the second controller, and the first output voltage of the third controller, and to operate the DC-DC converter based on the first final command voltage,
• wherein an operating cycle of the third controller is faster than an operating cycle of the second controller, and an operating cycle of the fourth controller is faster than the operating cycle of the third controller.