Open-Transistor Faults Diagnosis in Voltage-Source Inverter Based on Phase Voltages with Sliding-Window Counting Method

This paper presents a diagnosis method for open-transistor faults in voltage-source inverter (VSI) based on output phase voltages. When fault occurs, the faulty phase voltage will vanish during certain half periods, which can be utilized for diagnosing. In order to reduce calculation and improve noise resistance, the sliding-window counting method with first-in-first-out algorithm are introduced to detect the vanishment which indicates the faulty phase. Afterwards, the faulty transistor can be located by observing which half period the vanishment is in. Only output phase voltages are utilized and no complex algorithm is needed, thus this method can be easily embedded in existing voltage-loop or dual-loop controlled system without extra hardware circuits. Based on the time-domain characteristic of the faulty phase voltage, this method can achieve relative short detection time. Furthermore, it is capable of diagnosing simultaneous two-transistor faults. To validate the effectiveness of this method, experiments are carried out and discussed.