Individual Module-power Control With Minimum Power Loss for Solid-state Transformer-based Extreme Fast Charging Stations

This article proposes an individual module-power control with minimum power loss (IMC m ) for extreme fast charging (XFC) stations built with a cascaded-H-bridge multilevel (CHM)-based solid-state transformer (SST). In general, outputs of XFC are in a parallel configuration, having a DC-bus with an additional DC-DC conversion stage (Ad-stage). However, with IMC m , the DC-bus with Ad-stage can be eliminated because module powers of CHM-based SST can be controlled individually. This means that XFC stations only with a SST are possible; thus, low cost, small size, and less power loss can be achieved. To realize IMC m , this article takes the following. First, a modulation method based on one-pulse switching is suggested to control module powers individually with minimum power loss. Second, a reactive current injection strategy is described for the realization even under a light load condition. Finally, a control block diagram for implementation is provided. The proposed IMC m is verified by simulation results.