Upon further reflection, I think the answer to this problem is to simply coordinate charging 'slots' on a sub-grid(not sure what you call a local delivery circuit with a certain capacity). It should be possible to request charging time slots from a local power company server and negotiate when your vehicle can charge with millisecond accuracy. Doing so also might help the power company supply that power more effectively/efficiently. Sure, this means in peak times you may not get the charging rate you want, because you have to wait for the network to be available, but in off-peak times you get the fast charging rate you're capable of.