Research on the fault characteristics and fault diagnosis methods of three-level high-power inverter

As one kind of multilevel inverters, three-level inverter is widely used in the high-power and high-voltage applications. However, the increasing of the power devices improves the system's fault rate. How to ensure stable operation of the system has become an important research question. Through theoretical analysis and simulation on three-level high-power inverter, the paper analyses the working situation of the power devices of main circuit under the open-circuit fault, the specific fault characteristics and the typical waveform in detail, and sums up the rules of fault diagnosis. Finally, based on the three-level high-power inverter, the open-circuit fault experiment of power devices is carried out .The experimental results further validate the fault analysis and simulation results of the power devices.