Design and Development of a Multi-Port EV Fast Charger with Dynamic Control Strategy

Electric vehicles (EVs) demand is increasing due to their significant impacts on different aspects of society, the economy, and the environment. Unlike a normal-charger, a fast EV charger is critical for EV charging because it reduces the EV charging time significantly from several hours to just 30 minutes to 1 hour. To charge multiple EVs simultaneously and reduce the waiting time of other EVs, more power electronics converters are required which may also increase the infrastructure cost. To minimize the waiting time and infrastructure cost, and accommodate more EVs, a multi-port EV fast charger is designed in this paper. A dynamic mode control strategy is developed which not only controls the individual EV charging but also controls the charging of other EVs connected for charging in the meantime. In the developed dynamic control strategy, the charging current is controlled based on the state of charge (SoC) of each EV. When the SoC of any EV achieves its next predefined level, it triggers the mode synchronization and the level of charging current to all EVs connected to this multi-port charger adapts to change in real-time. Instead of a fixed charging current allocated to each EV, the charging current level for each EV dynamically changes even when one EV connected to a multi-port fast charger reaches to the next predefined SoC level. To design a multi-port offboard EV-fast charger, EVTECH & espresso charge standard specifications are used. The simulation is carried out using a Simulink environment to verify and evaluate the effectiveness of the developed dynamic mode control strategy for multi-port fast charger application.