Fault-tolerant operation of multilevel diode-clamped converters for a device open-circuit fault

This paper presents fault-tolerant operation strategies for a grid-connected three-level diode-clamped converter system. The proposed fault-tolerant control method enables continuous operation under device open-circuit failure conditions. The location of the faulty components is considered as identified. The fault-tolerant scheme is developed based on the inherent redundant voltage vectors in a three-level (3L) diode-clamped converter (DCC). By selecting an appropriate switching pattern, 3L-DCC can manage rated power with sinusoidal currents during faulty states. Therefore, the proposed solution requires no additional hardware and complex calculations. Simulation results prove the effectiveness of the proposed concept and confirm good fault handing capabilities.