Well, this is a 400kVA 3 phase transformer. You can estimate the size – it is roughly 2m wide. 11kV or 33kV input.
That will feed just one such charger.
Nah, rectify it then use a 1 MHz DC-DC converter, transformer the size of a thimble. Just need some hefty power transistors. Actually the latter do exist, the IGBTs used in things like trains are good for 1MW (1000A @ 1000V) though they do need some pretty hefty heatsinks.
The distribution will be at (UK) 11kV or 33kV, or even 110kV if you have a whole pile of these chargers, at 50Hz and that is the sort of transformer you will need for just one such charger. You are talking of 6 digit cost from the power company to install that.
What is in the charger and the car is another thing. Yes; modern power conversion is done at high frequencies but good luck switching 1kV at 1MHz 
You would be competing with the BBC World Service, Voice of America, and Radio Luxembourg all at the same time 
IGBTs don’t switch that fast anyway. I used to design these things.
Looking at ~100kW AC motor drives, the input to those tends to be ~3kV 3 phase. So most likely a 350kW charger won’t be fed with 230V.
I wonder if anybody knows anything about this? Does it exist?
The EV6 has a 77,4 kWh battery. Charging the battery from 10 to 80%, so 70% would require 54 kWh. 18 minutes at 350 kW is 105 kWh. The charging losses are low, especially if charging up to 80%, maybe a few %? Something doesn’t add up..
No 350 kW chargers available AFAIK.
High power DC chargers need 400V 3-phase AC at 500A per phase. Which sounds high but really the wire thickness required is the same as for the DC cable which at 350kW and 700V also has to conduct 500A. But these have to be short so such a charger will be right next to a 11kV substation.
11kV substations deliver anywhere between 500 and 1,500 kW (well, kVA, which for EV charging is the same).
A larger 1,500 kW substation can run four of these 350kW chargers at full tilt all of the time, but in practice 10 or more of these chargers will be installed. The chargers talk to each other and make sure that they are throttled if required.
As @Peter wrote, these substations are not small, altogether the supporting elecrics take the space of around 2 charging spots so around 15% of the total area required for the installation. Here is an aerial photo of a Tesla 12-charger installation, eight 250kW and six older 150 kW charger, with the substation (left) and AC-DC power circuits (bottom left).
Aren’t the high speed chargers DC?
In France there are approximately 300,000 EVs registered.
Total Energy have charger stations at the moment of up to 300Kw but they have a programme to install 350kw chargers this year. I can’t find how many at the moment.
I wonder where the charging control electronics are. This sort of power is not dirt cheap to implement, so I think most of the control hardware is in the charger, not in the vehicle. The vehicle will likely maintain control of its battery state but the charger will likely feed the battery pretty much directly – obviously with DC.
I thought the charger is built into the car.
Only some cars can take the whole 300kw at at time, making for the fast charge of 20mins or so..
Well, yes, normally, the battery charging controller and all electronics are in the appliance. The mains power unit is just a DC supply, say 12V.
But if you are going to be charging an appliance at 700V 500A (350kW) then the power electronics is not going to be cheap or compact and it makes sense to move it to the charger. It is a similar idea to TV broadcasting (originally done c. 1940): the complexity is in the data encoding and the transmitter and the TV appliance is very simple, with just a simple RF receiver and a driver for the scan coils.
A “plug-in” car obviously needs to be fully self-contained because it is getting 230V 50Hz input, but it takes days to charge a high end EV from a mains socket. It’s completely unviable unless you rarely drive, or the vehicle is very small (which itself is a big application sphere).
Anyway I am sure the information is out there…
But fast charge EV charge points are DC. I think the dividing line comes at around 120kw but it might well be less.
Whereas when you plug in at home, the same car is getting 240v 3kw to 7kw AC depending on type of connector and what type of installation you have at home. Or maybe the type 2 7Kw installation is DC also.
