Experimental Evaluation of Impact of Sustained Supply Voltage on Electric Vehicle Charging

The widespread adoption of Electric Vehicles (EVs), which increase electricity demand, has posed certain challenges for the electrical power system. Coupled with the elevated level of renewable energy penetration, distribution networks are encountering voltage regulation issues. This paper investigates the behaviour of EV chargers when exposed to rms voltage magnitudes across the allowable range through analysis of laboratory and field measurements of the electrical performance of several EV models and chargers, ranging from Level 1 to Level 3. The charger rms current, current total harmonic distortion (ITHD), displacement power factor (DPF), and power consumption have been measured. The data revealed that across the tested voltage range, the EV chargers primarily exhibited constant current (CC) behaviour, with some switching to constant power (CP) mode at higher voltage magnitudes. In addition, variation in supply voltage magnitude had no visible effects on the DPF, which remained close to unity, or ITHD. The outcomes of this study enable a more accurate understanding of EV load models, which aids the precision of power flow analysis, load management, and system planning.