A New Fault Tolerant SST Topology and Operation Strategy for Alleviating HVAC Grid Faults

One of the most important reliability concerns for Solid-State Transformers (SSTs) is related to high voltage side switches and grid faults. High voltage grid faults that result in unbalanced operating conditions in SSTs can lead to dire consequences in regards to safety and reliability in comparison to traditional transformers. The proposed SST overcomes occurrence of faults by balancing the output line-to-line voltages using a fault tolerant technique. This paper proposes a new SST topology in conjunction with a fault-tolerant operation strategy that can fully restore operation of the proposed SST in case of one of the grid fault scenarios. Preliminary theoretical and simulation results are provided to support the proposed idea.