Model parameter identification-based inverter fault diagnosis method

Three-phase inverters have been widely applied in modern industry, transportation, aerospace, and other fields, holding a significant position. To address the serious impact of open-circuit faults in three-phase inverters on the normal and stable operation of systems in practical applications, a detection and location method for inverter open-circuit faults based on model parameter identification was proposed. The method involved collecting the three-phase output currents of the inverter, performing Clarke transformation and normalization on the current values, and constructing an inverter parameter model. By combining the fast recursive algorithm with the parameter model, real-time parameter estimation was conducted for the inverter. The estimated parameters were used to form a fault diagnosis vector, which corresponded to a basic vector matrix library for 21 different types of switch faults in the inverter. During normal operation, the Euclidean distance between the monitored vector and the basic vector was close to zero. However, when an open-circuit fault occurred in the inverter, the Euclidean distance between vectors would quickly exceed a threshold. This change could be used to detect whether an open-circuit fault had occurred in the inverter. Upon detecting an open-circuit fault, precise localization of the faulty switch was performed. By comparing real-time Euclidean distance values with those in the basic matrix library, the fault label corresponding to the minimum distance was obtained. Consulting the fault classification table allows for the identification of the switch responsible for the open-circuit fault. Experiments on inverter faults were conducted on a hardware-in-the-loop simulation platform to validate the effectiveness and accuracy of the proposed method. The experiments included the diagnosis of open-circuit faults in different types of three-phase inverter switches under various loads. The results can demonstrate the method ability to accurately locate different types of three-phase inverter open-circuit faults and exhibited high robustness in fault diagnosis under different load conditions. © 2024, Central South University Press. All rights reserved.