Fast E.V. Charging.

I am not sure where the nominal 1000V comes from. It may be technology dependant. When the current EV generation (Lithium batteries, a few hundred volts, inverter with 3 phase motor) was being developed there were no standards. Milk float, FLTs, etc with lead acid batteries, generally less than 100V, brushed DC motors were not appropriate. Full size electric rail with a few thousand volts and over 1000kW in a single drive package was again not appropriate. I believe that tram and trolly bus technology was used, so a few hundred volts and drive packeges of a few hundred kW. Under 1000V single semiconductors can be used for swithching and DC fuses are reasonably practical. Moving above this brings a new set of problems.

Current EVs operate at around 400V so even 800-1000V charging is a problem. Porsche have used a DC-DC converter (cost and weight). Splitting the battery pack and using series-parallel switching would be another solution but that depends on how the modules are configured. I am not sure how charging at a few kV would work? A DC-DC converter could be used however a HF supply and just the transformer and rectifier on board may be lighter and cheaper.

Lots to think about.


Best regards


Roger

I am not sure where the nominal 1000V comes from. It may be technology dependant. When the current EV generation (Lithium batteries, a few hundred volts, inverter with 3 phase motor) was being developed there were no standards. Milk float, FLTs, etc with lead acid batteries, generally less than 100V, brushed DC motors were not appropriate. Full size electric rail with a few thousand volts and over 1000kW in a single drive package was again not appropriate. I believe that tram and trolly bus technology was used, so a few hundred volts and drive packeges of a few hundred kW. Under 1000V single semiconductors can be used for swithching and DC fuses are reasonably practical. Moving above this brings a new set of problems.

Current EVs operate at around 400V so even 800-1000V charging is a problem. Porsche have used a DC-DC converter (cost and weight). Splitting the battery pack and using series-parallel switching would be another solution but that depends on how the modules are configured. I am not sure how charging at a few kV would work? A DC-DC converter could be used however a HF supply and just the transformer and rectifier on board may be lighter and cheaper.

Lots to think about.


Best regards


Roger