APPARATUS AND METHOD FOR FAULT DIAGNOSIS OF SWITCHING DEVICE IN NEUTRAL POINT CLAMPED INVERTER SYSTEM

摘要

PURPOSE: A switching element fault diagnosis device of a neutral point clamped(NPC) inverter and a method are provided to diagnose a fault of switching elements in the NPC inverter without adding an voltage sensor. CONSTITUTION: A NPC inverter switching element fault diagnosis device includes a NPC inverter(1) and a fault diagnosis determination unit(2). The NPC inverter comprises a plurality of switching elements including an inverse diode by every three phase and a plurality of clamping diodes. The NPC inverter converts a DC current into a three phase AC current, and applies the same to a system. [Reference numerals] (2) Fault diagnosis determination unit; (20) Coordinate conversion unit; (21) Radius calculation unit; (22) Angle calculation unit; (23) Fault switching element determination unit; (AA) Positive bus of a DC link; (BB) Neutral point; (CC) Negative bus of the DC link