A power converting apparatus comprising: an input unit including an AC connection unit which is configured to receive an alternating current, AC, power from an external, a DC connection unit which is configured to receive a direct current, DC, power, and a relay which is configured to interrupt an input of the AC power received through the AC connection unit ; a bridge diode unit configured to output the DC power having a given polarity when the DC power is connected to the input unit , and to rectify the AC power received through the input unit when the AC power is connected to the input unit ; a DC input detection unit (S1) configured to detect an input of the DC power; an AC input detection unit (S2) configured to detect the input of the AC power; a capacitor (C) which is connected to a DC terminal which is an output terminal of the bridge diode unit ; and a controller configured to control the relay , characterized in that : the relay is configured to maintain a turned-on state except when the input of the DC power and the input of the AC power is both detected, and the controller is further configured to: control the relay to be turned off so that the input of the AC power is blocked when the input of the DC power and the input of the AC power is both detected; check a state of the DC power while the input of the AC power is blocked through the relay ; and control the relay to release the blocking of the AC power when a DC power failure occurs. an input unit including an AC connection unit which is configured to receive an alternating current, AC, power from an external, a DC connection unit which is configured to receive a direct current, DC, power, and a relay which is configured to interrupt an input of the AC power received through the AC connection unit ; a bridge diode unit configured to output the DC power having a given polarity when the DC power is connected to the input unit , and to rectify the AC power received through the input unit when the AC power is connected to the input unit ; a DC input detection unit (S1) configured to detect an input of the DC power; an AC input detection unit (S2) configured to detect the input of the AC power; a capacitor (C) which is connected to a DC terminal which is an output terminal of the bridge diode unit ; and a controller configured to control the relay , characterized in that : the relay is configured to maintain a turned-on state except when the input of the DC power and the input of the AC power is both detected, and the controller is further configured to: control the relay to be turned off so that the input of the AC power is blocked when the input of the DC power and the input of the AC power is both detected; check a state of the DC power while the input of the AC power is blocked through the relay ; and control the relay to release the blocking of the AC power when a DC power failure occurs. the relay is configured to maintain a turned-on state except when the input of the DC power and the input of the AC power is both detected, and the controller is further configured to: control the relay to be turned off so that the input of the AC power is blocked when the input of the DC power and the input of the AC power is both detected; check a state of the DC power while the input of the AC power is blocked through the relay ; and control the relay to release the blocking of the AC power when a DC power failure occurs. control the relay to be turned off so that the input of the AC power is blocked when the input of the DC power and the input of the AC power is both detected; check a state of the DC power while the input of the AC power is blocked through the relay ; and control the relay to release the blocking of the AC power when a DC power failure occurs. <EOS>