Apparatus and method for protecting grid-connected inverter from occurrence of low grid voltage

An apparatus for protecting a grid-connected inverter from occurrences of low grid voltage comprises: a first output current sensing unit for sensing output current from a grid-connected inverter; a first output current calculation unit for calculating D-axis and Q-axis currents of the sensed output current to obtain the sensed output current; a first output current control unit for determining whether the difference between the calculated output current and a reference current exceeds a set range, and if the difference therebetween exceeds the set range, then reducing the output current by an amount equal to a set value.