Measurement-Based Analysis of Power Quality and Harmonic Distortion Characteristics for Electric Vehicle AC Charging Modes

The rapid deployment of electric vehicles (EVs) has introduced new challenges to distribution networks, which are mainly related to power quality and grid reliability. Electric vehicle chargers behave as nonlinear loads because they are based on power electronic converters, which generate harmonic currents, cause voltage distortion, increase stress on network components, and might impact the overall power quality of distribution networks. In this study, power quality (PQ) measurements and harmonic characteristics were investigated for five electric vehicle models, namely the BYD Song Plus, Volkswagen ID6, Neta U, Nissan LEAF 2016, and Tesla Model 3. Measurements were carried out for different power levels—slow AC, low-power and fast AC, high-power charging modes—to evaluate the PQ characteristics and harmonic behavior of EVs. Fast charging power levels for most vehicles ranged between 5 and 11 kW, while slow charging ranged between 2.7 and 3.6 kW. It is found that harmonic characteristics, total harmonic current distortion (THDI), and harmonic distribution depend on the EV type and the charging mode. This study found that THDI varies between 1.5% and 10.72% for the tested EVs. Comparison with IEC power quality standards indicates that the impact of electric vehicle charging on voltage quality is limited, while current harmonic distortion varies significantly among vehicle models. Harmonic analysis reveals that the third and fifth orders dominate across most of the tested EVs, while the transition from slow to fast charging power level generally reduces low-order harmonics in most models, with vehicle-specific redistribution patterns that reflect converter topology and control strategy. The results also show that some EV chargers draw reactive power and operate with a lagging power factor, whereas other vehicles inject reactive power and operate under leading power factor conditions.