A method for compensating instantaneous power failure in an inverter including a plurality of power cells, each power cell comprising a rectification unit, a DC link unit and an inverter unit, the method comprising: determining whether an input voltage of the plurality of power cells is less than or equal to a first threshold voltage, the input voltage being supplied to the DC link unit through the rectification unit; decreasing, when the input voltage is less than or equal to the first threshold voltage, an output frequency of the inverter unit; determining whether a voltage of a direct current link unit is greater than or equal to a second threshold voltage; and increasing, when the voltage of the DC link unit is greater than or equal to the second threshold voltage, the output frequency of the inverter unit, characterized in, that the increasing of the output frequency of the inverter unit comprises: monitoring change of the voltage of the DC link unit resulting from regenerative energy supplied from a motor to the plurality of power cells and a restored input voltage, and increasing the output frequency by a predetermined value based on an increment of the voltage of the DC link unit at a time when the input voltage of the plurality of power cells, greater than or equal to the first threshold voltage, is restored, and a gradient of the output frequency is predetermined according to a load amount applied to the motor at the time when the input voltage of the plurality of power cells, greater than or equal to the second threshold voltage, is restored. determining whether an input voltage of the plurality of power cells is less than or equal to a first threshold voltage, the input voltage being supplied to the DC link unit through the rectification unit; decreasing, when the input voltage is less than or equal to the first threshold voltage, an output frequency of the inverter unit; determining whether a voltage of a direct current link unit is greater than or equal to a second threshold voltage; and increasing, when the voltage of the DC link unit is greater than or equal to the second threshold voltage, the output frequency of the inverter unit, characterized in, that the increasing of the output frequency of the inverter unit comprises: monitoring change of the voltage of the DC link unit resulting from regenerative energy supplied from a motor to the plurality of power cells and a restored input voltage, and increasing the output frequency by a predetermined value based on an increment of the voltage of the DC link unit at a time when the input voltage of the plurality of power cells, greater than or equal to the first threshold voltage, is restored, and a gradient of the output frequency is predetermined according to a load amount applied to the motor at the time when the input voltage of the plurality of power cells, greater than or equal to the second threshold voltage, is restored. monitoring change of the voltage of the DC link unit resulting from regenerative energy supplied from a motor to the plurality of power cells and a restored input voltage, and increasing the output frequency by a predetermined value based on an increment of the voltage of the DC link unit at a time when the input voltage of the plurality of power cells, greater than or equal to the first threshold voltage, is restored, and a gradient of the output frequency is predetermined according to a load amount applied to the motor at the time when the input voltage of the plurality of power cells, greater than or equal to the second threshold voltage, is restored.