A Novel Open-Circuit Fault Detection and Localization Method for the CLLC Converter

This article proposes a novel method for open-circuit fault detection and localization (OCFDL) in CLLC converters, which is characterized by high speed and independence from output load. The precise location of the open-circuit fault (OCF) is rapidly identified using voltage waveforms across the terminals of the resonance tank capacitor. After fault detection (FD), the converter employs a backup leg to address the issue and ensure uninterrupted power transmission. Compared to existing OCFDL methods, the proposed approach offers lower complexity, reduced implementation costs, and load independence. Experimental validation using a laboratory prototype demonstrates the theoretical advantages of the method in terms of speed, robustness, and effectiveness. Experimental results confirm the proposed method's ability to accurately detect and localize faults within 25 $\mu \text{s}$ and replace the faulty switch, ensuring reliable operation.