Single Sensor-Based Fault Localization and Detection in GaN Three-Phase Dual Active Bridge Converters

This paper presents a novel approach for single-switch fault detection and localization in three-phase dual active bridge (DAB) converters. The proposed control scheme leverages an existing current sense resistor that is typically used for output current regulation, to extract the necessary αβ parameters for detecting and localizing open-circuit faults (OCFs). Additionally, secondary-side short-circuit faults (SCFs) are detected and localized without the need for additional sensors. Simulated results demonstrate successful detection and localization of both OCFs and SCFs during 400V operation. The proposed method is validated on a 400V, 6.6kW liquid-cooled converter equipped with 650V GaN devices, operating at a switching frequency of 300 kHz and achieving a peak efficiency of 96.6% at 6.5 kW. Experimental results confirm the successful detection and localization of single-switch OCFs within four switching cycles.