A novel diagnostic method for single power switch open-circuit faults in voltage-fed PWM motor drives

Nowadays, variable speed AC drives have become a standard in many industrial applications. Hence, due to the widespread adoption of advanced power control devices, fault diagnosis of power converters, in particular the voltage source inverter in variable speed AC drives, is becoming more and more important. Although there are different fault types that may occur in these converters, in this paper, only single power switch open-circuit failures are considered in a vector controlled permanent magnet synchronous motor drive. A new real-time algorithm that allows the detection and localization of the faulty device using just the motor phase currents is proposed. Several results under different operating conditions are presented, proving the method effectiveness, low detection time and robustness against false alarms.