A real-time hardware-in-the-loop approach for estimating EV on-board charger efficiency and assessing its impact on EV users

Smart charging strategies mitigate the effects of large-scale and uncontrolled integration of electric vehicles (EVs) into the grid. These strategies rely on power modulation within the EV's on-board charger (OBC), which may reduce charging efficiency and increase energy losses. However, the impact of smart charging on both OBC efficiency and the end-user has not been fully addressed. This paper proposes a real-time Hardware-in-the-Loop (HIL) methodology to estimate OBC efficiency under different power modulation profiles, enabling more representative efficiency models. Results show that dumb charging draws 33.94~kWh to store 32.55~kWh in the battery (1.39~kWh losses), while smart charging increases losses to 2.01~kWh per charging session. These results highlight a direct impact on the users, who are billed for the energy delivered by the charging station rather than the energy actually stored in the battery.