Apparatus and method for diagnosis of fault of 3-level t type inverter switch

Disclosed are an apparatus and a method for the diagnosis of a fault of a 3-level T type inverter switch. The apparatus for the diagnosis of a fault of a 3-level T type inverter switch according to one embodiment of the present invention comprises: a 3-level T type inverter in which a first direct current link capacitor connected to a first direct current link and a second direct current link capacitor connected to a second direct current link are connected in series, and multiple inverse parallel diodes and a switch are connected, in a T type and for every three legs, to neutral points serving as connecting nodes between the first direct current link and the second direct current link and between the first direct current link capacitor and the second direct current link capacitor; a voltage calculation unit for calculating the difference between the voltage of the first direct current link capacitor and the voltage of the second direct current link capacitor; an average value calculation unit for calculating an average value of the current standardized for each leg using the output three-leg current of the 3-level T type inverter; a faulty leg diagnosis unit for diagnosing whether each leg is faulty or not using the average value of the current standardized for each leg calculated by the average value calculation unit; and a faulty switch determination unit for determining a faulty switch in the faulty leg using the average value of the standardized current of the leg diagnosed as being faulty as the result of the diagnosis of the faulty leg diagnosis unit and the difference between the voltage of the first direct current link capacitor and the voltage of the second direct current link capacitor.