BMW I3 Project

[arber333]

OK, it make sens... I tough the resolver poles pair was absolutely related to the number of lobs on the resolver rotor... 6 lobs = 3 poles pairs... but in this motor it's a 6 poles pairs on 6 lobs!

Resolver was set to 3PP and motor was set to 3PP (working but haft real speed)
But in real Resolver is a 6PP and motor is a 6PP (to be tested)

I took apart many traction motors an they usually have motor pole count same as resolver. Excitation to signal ratio is usually 2 to 1. Not the case with industrial resolvers. Some tamagawa resolvers even reverse the ratio to 1 to 2. So 3V3 on exciter would show 8V on signal return. This is why i couldnt run some bosch industrial motor with Openinverter...

[lumax]

Thanks for feed back, really appreciated!!!

Start looking in to the charger schematics...

From the BOOST charger docs:
"This mode is used if the DC input voltage is LOWER than the lowest battery pack voltage. For example rectified 230V AC results in 320V DC"

My battery pack have the following specs
96 cells @ 3.7V = 355.2V

ABSOLUTE Cell Vmin = 259.2V (2.70)
ABSOLUTE Cell Vmax = 393.6V (4.10)

Power available
120Vac = 170Vdc
240Vac = 340Vdc

So if I use 240VAC (340VDC) with the boost converter what will happen in the lower state of charge (between 259.2V and 340V) does the charger will be able to limit the current by PWM or it will stay ON and send infinite current to the battery ???

[lumax]

Lots of improvement since my last update

I had a problem... the motor has no regen, as soon as I try to apply brake, It accelerate rather than slowing down, I thought it was related to a bad parameter, so I tried all kind of settings with no luck, the problem was the syncofset... it was perfectly dialed in at example; 16000 but in fact I have found that it can also be tuned at example; 32000, and now I got regen as it is supposed

The BMW battery have been modded with simp bms and seem to work perfectly


Battery, inverter and motor have been tested together, so far so good... still a little problem with the simp bms current sensor reading, I got little false reading sometime, I will probably need to add a little filtering cap to the ADC input. Still need to implement the can message in the inverter to read battery staus

Next step is the charger, I will go with the boost mode at 120Vac, since the 240V is to high for my pack voltage, in fact I would need around 180Vac rectified to 254Vdc... Will see how it goes, I might also build charge station on 240V with a step down transformer or simply an auto transformer... will see

[johu]

So if I use 240VAC (340VDC) with the boost converter what will happen in the lower state of charge (between 259.2V and 340V) does the charger will be able to limit the current by PWM or it will stay ON and send infinite current to the battery ???

No, current will flow straight through rectifier and diode, nothing can stop it. Check the basic schematic of boost converters.
In practise it is mostly not a problem since there is not much charge between 2.5 and 3.4V. So you will be above 340V in most situations.
I have the same issue with Touran. Sometimes I did discharge it down to 280V and then I cannot use the boost charger as it would just trip the breaker.

[arber333]

Next step is the charger, I will go with the boost mode at 120Vac, since the 240V is to high for my pack voltage, in fact I would need around 180Vac rectified to 254Vdc... Will see how it goes, I might also build charge station on 240V with a step down transformer or simply an auto transformer... will see

I would rather recommend you use 3phase charging with buck setup. That way you will not run out of voltage . Also your house AC will be more gratefull because of better PF.

[johu]

Well, he'd have to move to Central Europe I'm starting to learn that 3-phase power (especially domestic) is actually quite exotic.

[lumax]

Well, he'd have to move to Central Europe I'm starting to learn that 3-phase power (especially domestic) is actually quite exotic.

Yes, It's quite exotic for us... only commercial / industrial got 3 phases here

[Scott166]

Hi @lumax

Did you already start to disassemble the battery pack? If so could you share some detailed photos + measurements of the modules? I would like to create a CAD model to see how I could fit them in my project – or if I have to go a different route after all. Thanks!

Have you got any more info on this?
B as in Bjorn and persteel on YouTube have some good videos on the i3 batteries.

[arber333]

Yes, It's quite exotic for us... only commercial / industrial got 3 phases here

Yes i understand why PF is so important. I could only get my 16A fuses to work with 2kW power from a single phase. But i used a split cap voltage doubler to get voltage up to 600Vdc and then to buck that to normal 360Vdc. It works rather nicely as emergency charger. PF is still dreadfull though.

[lumax]

Have you got any more info on this?
B as in Bjorn and persteel on YouTube have some good videos on the i3 batteries.

No, sorry and the battery will not be dismantled for now, since I use the complete battery for the project, SIMPbms have been installed on the battery without problem

i used a split cap voltage doubler to get voltage up to 600Vdc and then to buck that to normal 360Vdc

So you are doubling 220 50hz to 620V... How big is your cap (uf) and how many amps at the input ???
Never thought of building an high power voltage multiplier