Efficiency measurement and maximization for EV charging technologies

EV charging technologies could improve grid flexibility, reduce the charging infrastructure need, and increase revenues when their operating efficiency is higher. This paper presents this operating efficiency measurement of AC, DC, and V2G charging using different EV models. The common trend for all the charging technologies and EV models is their low efficiency at lower charging power. In AC charging, the operating efficiency is lower than 85% when operating at lower than 25% to 40% of the nominal power depending on the EV models. In DC charging, the efficiency is around 85.21% to 89.41%. The operating efficiency of V2G is lower than 85% when operating around 10% to 15% of the nominal power. The charging efficiency is higher than the discharging one. The average round-trip efficiency is around 76.12%. Several solutions to maximize this operating efficiency are discussed based on the measurement results.