Individual Module Power Transmission Control for Extreme Fast Charging Stations Configured With Solid-state Transformer

This paper proposes individual module power transmission (IMPT) control for extreme fast charging (XFC) stations configured with a solid-state transformer (SST). Generally, since module powers in SST are not controlled individually, module outputs are in parallel connection to form DC-bus. This means additional power conversion stages consisting of DC-DC converters should be connected to DC-bus in SST-based XFC stations in order to charge multiple electric vehicles (EVs) simultaneously. However, with the proposed IMPT, module outputs of SST can be connected to EVs directly without additional power conversion stages, resulting in low construction cost and power loss. In this paper, first, the modulation method is suggested for synthesizing switching reference voltages individually in the AC-DC conversion stage. Second, reactive current injection is considered for full-range operation regardless of the number of charging EVs. Finally, the control block diagram that realizes IMPT is presented. The validity of IMPT is demonstrated by simulation results.