Apparatus and method for charging balance and grid connected type battery charging and discharging system thereof

摘要

PURPOSE: A charge balancing apparatus and a grid connected battery charge and discharge system using the same are provided to prevent an electrical power system to become bigger and configuration costs to be increased by creating DC input voltage without using a bidirectional boost DC-DC converter. CONSTITUTION: First and second batteries(110,120) are serially connected between a first electrode(P) and a second electrode(N). One side of an inductor(130) is connected to a contact point of the second battery and the first battery. A first switch(140) is connected between the first electrode and the other side of the inductor. A second switch(150) is connected between the second electrode and the other side of the inductor. A switch operation control part(160) outputs first and second switch control signals for operating the first switch and thee second switch when difference in electric energy which is charged in the first and second batteries is generated.