Harmonic Evaluation of Electric Vehicle Charging Rectifier Circuits

Electric vehicles operate with rechargeable battery systems, which are critical in achieving zero carbon emission targets. EV chargers, which enable the conversion of alternating current, which is the energy source of these vehicles, into direct current, include various rectifier circuits according to different charging modes (Mode 1, Mode 2, and fast DC charging). This study investigated the harmonic effects of rectifier circuits on the electrical system in single-phase, three-phase, and DC charging modes. As a result, it was determined that three-phase six-pulse rectifier circuits have lower harmonic content compared to single-phase rectifiers by keeping the total harmonic distortion (THD) value of the current drawn from the grid below approximately 20%. This is possible thanks to the elimination of 3rd and multiples of 3 harmonic components in three-phase systems and the achievement of lower fluctuations in the DC link voltage. These findings show that three-phase rectifier circuits provide a cleaner and more efficient power source, even without a filter capacitor.