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Voltage-source inverter is a significant part of power supply for various applications. In hard working conditions, the inverter is prone to failure, such as open-circuit (OC) faults, which bring great risk to the safe operation. Therefore, a simple and robust fault diagnosis method for OC faults of voltage-source inverter is proposed. First, the fault principle of OC fault is studied, and a rule of voltage sequence is found that the sequence of positive and negative abnormal voltages is related to the fault position. Then, available line voltages are used as fault diagnosis variables, the fault phase is detected by abnormal values of line voltages, and the fault switch is located according to the fault phase and the rule of voltage sequence. Different from existing OC fault diagnosis methods, the proposed method is immune to phase to phase short-circuit fault, which has not been referred to or discussed in existing literatures yet but can lead to the false diagnosis of OC fault diagnosis methods. Moreover, the proposed method is robust to load variation, switching and fundamental frequencies. The experimental tests are carried out on a dSPACE platform, and the proposed method is verified. [ABSTRACT FROM AUTHOR]

The safety and reliability of inverters play a significant role in stable power electronic system operations. Considering a railway vehicle air-conditioning inverter as a case study, this paper presents a generic open-circuit fault diagnosis method that can be applied to various inverter and control schemes. First, a detailed model of three-phase output currents under both normal and fault status is derived, and then the concept of space trajectory is introduced based on the three-phase output currents. The open-circuit faults of the inverter lead to output phase current distortion. Therefore, different types of faults have different space trajectories, and the corresponding shape of the space trajectory is considered to be a fault feature. Then, the fault is located by the direction vector and center-of-mass coordinate. The effectiveness and reliability of the diagnosis method are verified and analyzed using a hardware-in-the-loop test platform. [ABSTRACT FROM AUTHOR]

A noninvasive diagnosis method for open-circuit faults of a locomotive inverter is proposed. Two different voltage transients are defined according to output voltage values, and the ratio of them is used for diagnosis. Faults can be detected immediately when they occur. The method and its robustness are verified on dSPACE. [ABSTRACT FROM AUTHOR]