A Carrier-Based Fault-Tolerant Control Method for Three-Level Neutral-Point-Clamped Inverter

This paper firstly analyzes the space vectors that can be used when a single switching device of three-level (3-L) neutral-point clamped (NPC) inverter has a short-switch or an open-switch fault. On the premise of avoiding two-level voltage jump and simultaneous action of three-phase switching devices, a fault-tolerant space vector sequence (FTSVS) is designed which can be applied to any fault of a single switching device. On this basis, the equivalent relationship between FTSVS and carrier-based PWM (CBPWM) is deduced, and a carrier-based fault-tolerant control (CBFTC) method is further proposed. It can realize the fault-tolerant operation of 3-L NPC inverter and ensure the balance of the neutral point voltage, and its calculation is simple and implementation is convenient. Simulation results verify the validity of the proposed method.