BMW I3 REME Inverter Reverse Engineering

[sdobbie]

Hi everyone, I have been doing more work on reverse engineering the small inverter for the range extender on the I3 with the intention of creating a vesc board for it. I thought everyone here would also appreciate some pinouts and images so that we can create an openinverter board for it too. It may never work in vesc as vesc requires phase voltages to work and I do not want to create a board where the customer is to solder stuff onto the high voltage pins. Here is the pinout I have so far for the ribbon connector on the top board. There are a few strange signals on it I do not understand. The DC input voltage is measured using one of four channels on an ADS7841 ADC which is isolated via ADUM1401, the following shows where each ADC channel is connected to. The other three channels measure the IGBT temperature on each phase.

Here is the ribbon pinout where the interface for the ADC is shown on the left.

This is the bottom of the board with the HC6H800-S current sensors on it.

This is the other isolator which is attached to a two channel comparator, one of the channels is picking up a 793KHZ signal from somewhere and feeding it back to the mainboard. No idea what the other channel does.

My original disassembly video
https://www.youtube.com/watch?v=V54dUIX68ms

[johu]

Thanks for posting.
A similar measuring setup is used in the main drive inverter viewtopic.php?p=23956#p23956

[gourab]

Hello,

I am very new to power electronics, I wanted to know how many capacitors do we use in an Inverter and what sort of capacitors would be most useful.

Thank you
Gourab

[sdobbie]

After doing a bit more, I found these PTC devices on one of the boards in the inverter, they seem to be attached to a digital isolator via a voltage comparator. Any idea what they do?

[johu]

First guess would be overtemp shutdown but then that's a lot of drama. I'd ignore it for now

[CarTek]

Hello There,

Is there a chance you can provide a measurement at the inverter between the two HVIL pins at the inverter connector?
I do not have access to an inverter myself to make the test.
If tou can grab a measurement and post rhe resistance value it will be greatly appreciated!

Thanks,
C