Dynamic EV charging mode to support LVDC Microgrid operation

Abstract

The rapid proliferation of Distributed Energy Resources (DERs) and Electric Vehicles (EVs) has accelerated the adoption of Low-Voltage Direct Current (LVDC) microgrids (MGs). Efficient control of DC fast chargers within these networks is critical for maintaining system stability and efficient operation. This paper presents a primary control strategy for EV chargers that utilizes the ISO 15118-20 communication protocol to support LVDC microgrid operation. By leveraging the standard’s Dynamic Charging Mode and Bidirectional Power Transfer (BPT) capabilities, the proposed system adheres to Current/OS droop control rule setpoints without requiring session renegotiation with the vehicle. Experimental tests showed an average reaction time of 31 ms under normal voltage-ramp conditions, whereas current interruption times varied between approximately 6 ms and 570 ms depending on power-flow direction and fault scenario, and full bidirectional mode reversal required approximately 3.2 s in total.