NPC 3레벨 PWM 인버터에서 고장 발생에 따른 고장 진단과 중성점 전압 제어

The 3-level converter/inverter system is very efficient In the ac motor drives of high voltage and high power application. This paper proposed a simple method to diagnose faults using change of current vector pattern In space vector diagram when the faults occurrence In the 3-level Inverter and a control method that can protect system from unbalance of the neutral point voltage according to faults. The validity of the proposed method IS demonstrated by the simulation results.