Open-Circuit Fault Diagnosis for Interleaved Totem-Pole PFC Converter Based on Inductor Current Path Modelling

Online fault diagnosis is crucial for ensuring reliable operation in interleaved totem-pole power factor correction (PFC) converters. In this paper, a fault diagnosis and localization strategy for open-circuit faults based on the inductor current path modelling with diagnostic interval threshold is proposed. By analyzing the behavior of the inductor current and the input voltage phase during open-circuit faults, branch inductor currents are employed as the fault indicator. Specifically, an inductor current path model is established based on the instantaneous input voltage and the inductor current. This model helps in extracting open-circuit fault features and establishing the relationship between fault criteria and location. Furthermore, by investigating the influence of the phase error and current sampling frequency, a diagnostic interval threshold is introduced. This threshold can suppress the interference caused by zero-crossing distortion in the inductor current. The proposed method eliminates the need for additional hardware or complex algorithms. Experimental results verify the effectiveness of the proposed strategy.