In this paper, the problem of open-switch faults of a voltage source inverter system is investigated. A new fault diagnosis method based on an observer and an adaptive threshold is proposed. This method only needs to utilize the signals existing in a system without the need for extra hardware circuits. First, an observer is designed on a model of a three-phase voltage source inverter system to estimate currents. Then, an adaptive threshold is designed on fault residuals, dynamics of the currents and variations of the system operating state. Moreover, the dead time and switching delay time are also included in the threshold to consider practical applications. Furthermore, to achieve on-line real-time diagnosis and to improve the reliability of the proposed method, the averages of the current residuals in a current fundamental period are defined as diagnostic variables. Finally, the reliability and effectiveness of the proposed method are verified by simulation and experiment results.

中文翻译：

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基于观测器的电压源逆变器开路故障自适应阈值诊断方法

在本文中，研究了电压源逆变器系统的开路故障问题。提出了一种基于观测器和自适应阈值的故障诊断新方法。这种方法只需要利用系统中存在的信号，不需要额外的硬件电路。首先，在三相电压源逆变器系统模型上设计了一个观测器来估计电流。然后，针对故障残差、电流动态和系统运行状态的变化设计了自适应阈值。此外，死区时间和开关延迟时间也包含在阈值中以考虑实际应用。此外，为了实现在线实时诊断并提高所提出方法的可靠性，当前基本周期中当前残差的平均值被定义为诊断变量。最后，通过仿真和实验结果验证了所提方法的可靠性和有效性。