Single power switch open-circuit fault diagnosis in voltage-fed PWM motor drives by the reference current errors

Due to the widespread adoption of variable speed ac drives in many industrial applications, power converters fault diagnosis is becoming more and more important, particularly for the voltage source inverters used in these systems. Accordingly, this paper presents a new diagnostic method that allows the real-time detection and localization of single power switch open-circuit faults in VSI-fed PWM motor drives. The proposed algorithm is quite simple and just requires the measured motor phase currents and their corresponding reference signals, available from the main control system. Several simulation and experimental results using a vector controlled permanent magnet synchronous motor drive are presented, showing the diagnostic method effectiveness, through a relatively fast detection time and its robustness against false alarms.