Performance of diagnosis methods for IGBT open circuit faults in voltage source active rectifiers

Fault diagnosis of electrical drives is becoming more and more important today, since variable speed drives have become industrial standard in many applications. As an integral part of the drive, many faults occur within the inverter. One possible fault within the inverter is an open circuit transistor fault, whose diagnosis is subject of this paper. The practical performances of several open-circuit fault diagnostic methods are tested in simulation and experiment. An overview of the different strategies is given, including the algorithms used to localize the open transistor. Simulation results are presented and show different capabilities of each diagnostic strategy in terms of effectivity and false alarm resistivity for a voltage source inverter used as an active rectifier. The existing methods are further developed and adapted to a closed loop controlled active rectifier. An experimental setup in the laboratory is used to validate simulation results. Typical detection results are presented including time-to-detection measurements.