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.