A new fault tolerant NPC converter system for high power induction motor drives

Neutral Point Clamped (NPC) converter topology is one of the most common static conversion structures used in high power medium voltage motor drives. In recent years, fault tolerance has become one of the most interesting features which could be requested by the market, in order to improve drives reliability and availability, thus avoiding the stop of means of transport and/or plants. This paper proposes new fault tolerant strategies for NPC inverter feeding asynchronous motor drives supplied by Active Front End (AFE) or Diode Front End (DFE) converters with very low cost and small complexity increase.