Investigation of fault modes of voltage-fed inverter system for induction motor drive

The authors describe a systematic investigation into the various fault modes of a voltage-fed pulse-width-modulated (PWM) inverter system for induction motor drives. All the fault modes were identified, and a preliminary mathematical analysis was made for the key fault types-namely, input supply single line to ground fault, rectifier diode short circuit, inverter transistor base drive open, and inverter transistor short circuit conditions. The predicted fault performances were substantiated by a simulation study. The study was used to determine stresses in power circuit components and to evaluate satisfactory postfault steady-state operating regions. The results are equally useful for better protection system design and easy fault diagnosis