Apparatus for balancing voltages of dc link capacitor in inverter

An apparatus for balancing voltages applied to first and second capacitors in an inverter system including a smoothing unit configured with the first and second capacitors which are equivalently connected in series to each other, comprising:

• first and second resistors connected in series to each other, wherein the serial connection of the first and second resistors is connected in parallel to the smoothing unit;
• a switching unit connected to a node (a reference point) between the first and second resistors and a node (a neutral point) between the first and second capacitors and configured to short and open between the reference point and the neutral point;
• a control unit configured to control the switching unit to short between the reference point and the neutral point when a voltage of the reference point (a reference point voltage) and a voltage of the neutral point (a neutral point voltage) are different from each other;
• and
• a voltage measuring element connected between the reference point and the neutral point.