Enhanced Fault Detection, Localization, and Tolerance Strategy for Dual Active Bridge DC–DC Converters Through Frequency-Domain Analysis of Remote Voltage

Featuring high control flexibility, high efficiency, and fast dynamic response, modular dual active bridge (DAB) dc–dc converters have been frequently employed for energy conversion and management. However, DAB converters are also susceptible to open-circuit faults, primarily attributed to the vulnerability of the power switches. Therefore, a fault detection, localization, and tolerance control method is proposed in this work, based on frequency-domain analysis of far-end or remote voltage. The frequency characteristics of DAB converters in normal and faulty operations are analyzed. From the perspective of remote fault monitoring and diagnosis, the output voltage is used as the characteristic variable for fault feature extraction. The detection and localization of an open-circuit fault involve an analysis of the fundamental and second harmonic components of the output voltage. The associated fault tolerance control method is implemented by isolating a specific secondary-side switch. The realization of the proposed method is straightforward and cost-effective, requiring no additional devices and sensors. The feasibility and effectiveness of this approach are validated through simulation and experimental results.