Analysis and control of active neutral-point-clamping three-level inverters under fault tolerant operation modes

This paper studies the fault tolerant control schemes for the active neutral-point-clamping three-level (ANPC-3L) inverters under different fault conditions. The fault conditions include the device-level faults in one inverter leg, the inverter-leg faults, and the open-circuit faults in load. The impacts of faults in devices, inverter leg and load on output voltage levels and mid-point voltages of DC link are analyzed in detail. Based on those, the syntheses of remaining voltage vectors and reconfiguration of power circuits are developed to implement the fault tolerant control. The experiments on a laboratory prototype are given to verify the validity of the theoretical analysis and control schemes.