Patent ID: 9712043
Date: 2017-07-18
CPC Classifications: H02M

Claim:
1. An apparatus of controlling overcurrent of a grid-connected inverter due to an abnormal grid voltage, the apparatus comprising: a grid voltage sensor configured to sense a grid voltage according to an output current of the grid-connected inverter; a voltage variation calculator configured to calculate a D-axis voltage and a Q-axis voltage of the grid voltage to obtain variation values of the D-axis voltage and the Q-axis voltage; an output current controller configured to determine whether at least one of the D-axis voltage variation value and the Q-axis voltage variation value exceeds a set value of the grid voltage variation, and decrease the output current by a predetermined value when one of the D-axis voltage variation value and the Q-axis voltage variation value exceeds the set value of the grid voltage variation; and a timer configured to count a predetermined time period after decreasing the output current by the predetermined value,