Analysis of bidirectional DC fast charging according to distribution transformer loading conditions

In this paper, a bidirectional dc fast charging system for electric vehicle is analysed by considering its impact on the distribution transformer. The proposed battery charger topology combines constant voltage and constant current strategy as the battery charging control techniques. Both of working mode works interchangeably depends on distribution transformer loading condition. The model is verified by simulation that is performed by using a Thevenin model of a battery. The calculation time of charging battery is also performed for each working mode. Moreover, the impact of the dc fast charging system to the harmonics of the distribution grid is also analysed. It can be shown that the total harmonic distortion impact of charging infrastructure is less than 5%.