Single IGBT Open‐Circuit Fault Mitigation in Cascaded Converters Using Zero‐Mode Control and Half‐Wave Reconfiguration Composite Control

This article proposes a composite fault‐tolerant control strategy combining zero‐mode control and half‐wave reconfiguration to address single IGBT open‐circuit faults in cascaded H‐bridge converters. The composite strategy enables continuous operation without bypassing faulty modules by dynamically adjusting the working modes of faulty modules and reconstructing modulation waves for cascaded converters. The zero‐mode control strategy, as the core of this study, adopts a digital logic‐based architecture and utilizes the zero‐mode equivalence of the two operating modes of the H‐bridge module to dynamically switch modes according to the fault type. Through collaboration with the half‐wave reconfiguration control strategy, precise compensation for missing positive or negative voltage levels caused by faulty modules is achieved within a specific interval, ensuring that the cascaded converter can maintain output characteristics even under single IGBT open‐circuit faults and meet the requirements of grid‐connected operation. The maximum power control strategy dynamically adjusts the output power of faulty and healthy modules to minimize power deviations between them, thereby optimizing energy distribution efficiency and extending the lifespan of the battery energy storage system. Experimental results validate the effectiveness of the strategy in addressing single IGBT faults in cascaded energy converters.