Highly Power Dense MVDC to LVDC Conversion for Fast EV Charging Applications Based on N-Switch-Leg MAB Converter

This article proposes a medium voltage DC (MVDC) to low voltage DC (LVDC) high power multi-active bridge (MAB) converter utilising a single core multi-winding transformer for fast EV charging applications. The proposed converter eliminates the need for a low-frequency bulky transformer and offers bidirectional power flow with Zero Voltage Switching (ZVS) capability. In comparison with the state-of-the-art topologies, the proposed converter offers less dv/dt, which enables high-frequency operation, reducing the size of magnetics and EV charging station footprint. In addition, the proposed converter also eliminates the need for series-connected module capacitors and the requirement for voltage balancing control. The steady-state analysis and control algorithm of the topology has been operated with the conventional Single-Phase Shift (SPS) modulation scheme. The proposed converter is validated with simulation studies carried out in PLECS software. Also, a scaled-down prototype of the proposed converter is developed and operated for a 1kW load.