Inverter

The present disclosure relates to an inverter, and more specifically to an inverter that can be restarted stably by determining whether to restart it when power is supplied after a failure has occurred in the inverter due to a fault in the main supply. The inverter includes: a first restart reference voltage generator (210) configured to receive three phase currents output from the electric motor (250) and a frequency of the inverter and a rating current of the motor to output a first restart voltage and a first restart phase angle; a second restart reference voltage generator (220) configured to receive an inverter output voltage output from the inverter to output a second restart voltage and a second restart phase angle; and a switch unit (230) configured to the first restart voltage, the first restart phase angle, the second restart voltage and the second restart phase angle to output a restart voltage and a phase angle according to a restart flag. The inverter determines whether to restart an inverter bas