Wireless Distributed Control with Open-Phase Fault-Tolerance for Delta-Connected Three-Phase Three-Wire Solid-State Transformers

This paper proposes wireless distributed control with a fault-tolerant for a solid-state transformer (SST) in single-wire open fault. A voltage imbalance occurs at the input side of each cell in the SST when an open-phase fault occurs. The voltage imbalance causes overmodulation in the power factor correction (PFC) converter. The proposed method employs the current droop control as an autonomous distributed control to achieve the voltage balance of each cell and prevent overmodulation without communication among each cell. The proposed method reduces the imbalance of the input voltage among series-connected cells by up to 95% compared to the control without the current droop control. Moreover, continuous operation is achieved during single-wire open-phase faults.