The switch open-circuit faults can cause a large distortion in output voltages and currents of power converters,thus reducing the performance of the converter.After the occurrence of a open-circuit fault,the remaining power switches may have higher losses,therefore increasing the probability of secondary faults in the circuits.A fault diagnosis method for switch open-circuit faults of three-phase inverters is proposed in this paper.The identification of fault type and faulty switches is achieved by analyzing the output voltage patterns on αβ plane,with only the filtered output line voltages required to be measured.The proposed method is easy to implement and it can diagnose all conditions of switch open-circuit faults in a three-phase inverter.Finally,the feasibility and accuracy of the proposed method is verified by simulations and experiments.
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