Open Circuit Fault Diagnosis of NPC Three-Level Inverter Based on Stator Voltage Errors

This paper presents an open circuit fault diagnosis method of NPC three-level inverter based on stator voltage error. The three-phase stator voltage error is taken as the characteristic quantity, and the fault phase is quickly located by comparing the magnitude, positive and negative relationship between the stator voltage errors of different phases, and then the hybrid logic dynamic fault model is used to distinguish the power components from the inner and outer parts of the bridge arm. This method does not need to add additional sensors, requires little calculation of fault location, and avoids the influence of load dependence on the selection of diagnostic thresholds, so it has a good engineering application prospect.