Method of controlling state of charge (SOC) of battery, apparatus for controlling SOC of battery, and recording medium having stored therein computer program to execute the method

A method of controlling state of charge (SOC) of a first battery and a second battery that are connected in parallel with each other, the method comprising:

• calculating the SOC of the first battery and the SOC of the second battery;
• controlling output voltage command values of a first direct current (DC-DC) converter and a second DC-DC converter based on the SOC of the first battery and the SOC of the second battery, the first DC-DC converter and the second DC-DC converter being connected to ends of the first battery and the second battery, respectively;
• and
• controlling the SOC of the first battery and the SOC of the second battery to match each other based on the controlling of the output voltage command values of the first DC-DC converter and the second DC-DC converter,
• wherein the controlling of the SOC of the first battery and the SOC of the second battery comprises:
• performing an SOC average control operation by amplifying a difference between an average SOC of the first battery and the second battery and the SOC of the first battery or the SOC of the second battery;
• and
• performing an excess component output operation to output an excess value by comparing an SOC limit value of the first battery and the second battery with the SOC of the first battery or the second battery, and
• wherein the controlling of the SOC of the first battery and the SOC of the second battery further comprises performing an SOC limit value control operation by outputting a value obtained by multiplying the excess value output by the excess component output operation by a signal before amplification by the SOC average control operation.