A new Method of Open-Circuit Fault Diagnosis for Voltage-Source Inverter in UPS System

In this paper, a open-circuit fault diagnosis method for voltage-source inverters (VSI) in uninterruptible power supply (UPS) system is proposed. Being distinct from other fault diagnosis methods for inverters feeding ac motors innovated and promoted in the past few decades, this method presented at this stage aims at increasing the stability of operation in UPS system, which plays an irreplaceable role nowadays. Through the diagnosis method, the reliability of the VSI in UPS system can be monitored in real timey. In terms of diagnosis parameters, they are extracted from phase currents, which means there is no need for extra sensors due to its existing of the phase current in the UPS system. The simulation results at last prove its reliability, practicality as well as robustness.