garygid said:
While charging, battery voltages as low as 280 or so have
been reported for a Turtle-stopped battery pack.
A voltage of 420 plus or minus a bit might be required
for charging at higher currents.
However, during the "mating dance", it appears that the
output voltage must climb to the max (maybe 450 is sufficient,
but we do not know the exact number).
Also, the output voltage must fall to within a few volts of zero,
but again we do not know the exact number).
OK thanks Gary, that helps and those numbers will be the target to include in the 12kW design.
Note that it would be no problem at all to go another 50V higher just for the initial "mating dance"
as that would be solved with adding a small 48V supply that I have plenty of.
My intend was indeed to allow the power supply to go to full voltage and zero voltage (no current
in both cases) as well as the normal charging voltages, which I suspect are *entirely* determined by
the Leaf battery voltage and the charger is only *current* controlled.
I have not yet been able to decode the loggings you made from the CAN bus, so it is only a guesstimate.
garygid said:
Presently we are using an AVR-CAN development board because
it has one CAN interface completely included
That sounds like an interesting board. I see that Olimex offers it for 25 Euro while Mouser carries it for $35.
I will need to look into that board to see if the 35 GPIO that it has also offer DAC and ADC to control the
power supply to build it into a charger without further additional controllers or interfaces, otherwise a
PWM output and comparator are needed to add the necessary glue to the power supply.
garygid said:
Our primary control of the Power Supply is by
providing the Pulse Width Modulated (PWM) control signal to
the output regulating switcher stage of the Power Supply.
Owww, no wonder that you need a lot of processing power - that is a hard way to solve this problem.
From your reference to the Arduino I conclude that you use it to control the power supply?
Or is the CAN interface an Arduino shield and controlled by the Arduino also?
I get the impression from the Olimex website that it is a stand-alone controller,
you are probably using it as a simple CAN-to-RS232 converter for logging the CAN bus,
but I think the logic to control the power supply should be simple enough to add that
code to the CAN bus board and make it a stand-along board, so you only have the
8 (or 9) 48V power supplies with this CAN board in a box and the only two wires are
the 240V AC input and the Leaf fast charge cord, which contains the DC bus to the
battery and the CAN bus. Possibly a user selectable max power setting in case he
does not have the full 12kW 240V 50A, but for example needs to run half power because
he only has a dryer outlet (30A) or plugs into a J1772 that only allows 24 or 30A.