Optimal charging of large-scale electric vehicles over extended time scales

The multi-day spaced charging, hardly considered in current strides aiming at optimal electric vehicle charging, is the concern of this study, and thus, an extended time scale covering several days should be dealt with. This study firstly analyzed the routines and implementations of charging behaviors over the extended time scale and then quantified the range of charging start time of electric vehicles precisely, which turned out to be discontinuous, huge and complicated. Finally, the mathematical formulation of the optimal charging strategy over the extended time scale as well as its constraints was established. The proposed problem can be solved by MATLAB simulations, which was addressed in details. Moreover, numerous simulations were conducted and demonstrated that the proposed strategy can reach a better system load characteristics than the ordered charging on a daily basis with a good maneuverability.