Small drive unit inverter teardown and repair

EV_Builder · Post by **EV_Builder** » Wed Apr 13, 2022 6:23 pm

Ok but if power is lost of the buffer the outputs go to?

catphish · Post by **catphish** » Wed Apr 13, 2022 7:49 pm

EV_Builder wrote: ↑Wed Apr 13, 2022 6:23 pm Ok but if power is lost of the buffer the outputs go to?

I'm not sure about that, it wasn't the focus of my testing. I don't know if there are already pulldowns in the power stage. If 12v power is lost the IGBTs will also not be powered, but I don't know the exact order in which this will happen. Pulldowns on both sides of the buffer are a god idea really.

arber333 · Post by **arber333** » Wed Apr 13, 2022 7:57 pm

catphish wrote: ↑Wed Apr 13, 2022 6:15 pm
They should be pull-downs (probably 10k) on the lines between the STM32 and the 74HC buffer.

That was exactly what i used to actively pulled down non active gates since volt inverter used active low commands. I even used 6k8 resistors for more pulldown power. I used hex inverter with active high signals and did not trust stm32 signal inversion.
At first when i was playing with signals i would get a jolt when resetting controler. Then i figured it was bootloader...

EV_Builder · Post by **EV_Builder** » Thu Apr 14, 2022 1:06 am

catphish wrote: ↑Wed Apr 13, 2022 7:49 pm I'm not sure about that, it wasn't the focus of my testing. I don't know if there are already pulldowns in the power stage. If 12v power is lost the IGBTs will also not be powered, but I don't know the exact order in which this will happen. Pulldowns on both sides of the buffer are a god idea really.

No prob. we try to make best decision. I need to see datasheet.
Also we should make a scope recording of a reset and reboot etc.
pull-up/down to be sure nothing strange happens.

js1tr3 · Post by **js1tr3** » Sat Apr 23, 2022 11:15 pm

Loaded up the new firmware and had some success until today.

Looks like I might need a 3rd drive unit... everything was running with the new firmware at 48V. Ran fine at 340v with wheels In the air. Went to take a test drive today and blew the 350A fuse when closing the contactors.... 0.2 ohms at the hv input... again.

EV_Builder · Post by **EV_Builder** » Sun Apr 24, 2022 6:36 am

Did you pre-charge? Before closing the contactors?

js1tr3 · Post by **js1tr3** » Sun Apr 24, 2022 10:33 am

Yes, I had the precharge set for a fixed time, of 1s from the BMS. it worked fine the day before..
based on the 14 ohm resistor and 340 pack voltage, that should limit the inrush to a reasonable 24A.

js1tr3 · Post by **js1tr3** » Sun Apr 24, 2022 10:41 am

Beginning to think it has something to do with HV applied but no 12V. I had the car on the charger all day harvesting solar energy, so the HV was on but the inverter 12V was switched off.

catphish · Post by **catphish** » Sun Apr 24, 2022 7:18 pm

js1tr3 wrote: ↑Sun Apr 24, 2022 10:41 am Beginning to think it has something to do with HV applied but no 12V. I had the car on the charger all day harvesting solar energy, so the HV was on but the inverter 12V was switched off.

I'm sorry about your drive unit :'(

While I'm not certain of the details, I would suggest that applying HV and not +12V is dangerous for the same reason that applying HV during a firmware update is. The IGBTs are in an undefined (possibly floating) state.

With that said, I don't understand why HV would ever be applied if there was no +12v, as the contactors shouldn't be closed, and the charger would be on the battery side of the (open) contactors. Is this not the case in your setup?

js1tr3 · Post by **js1tr3** » Sun Apr 24, 2022 8:04 pm

No the contractors are between the battery and everything, Actually I have two mid-pack Contractors since the pack is split front/rear and the HV leads run through the heating ducts from front to rear. something in my mind thought that leaving the inverter unpowered was acting as a charge lockout to prevent drive away under charge.

I will add a 2nd separate contractor and precharge for the motor and one for DC/DC and Brusa charger, I had everything controlled by the BMS... since I was running a Soliton1 controller with a warp11 motor previously.

guess its time to move the contractor and precharge control over to the SDU, and re-wire the 12V

anyone have a good source for just an inverter?

js1tr3 · Post by **js1tr3** » Mon May 09, 2022 10:16 pm

Some progress.

Gooey gooey

http://warpedporsche.blogspot.com/2022/ ... rdown.html

js1tr3 · Post by **js1tr3** » Mon May 16, 2022 6:25 pm

After picking potting compound for an hour I realized Everything is resistance welded.

Now I need that hacksaw!!!

Roger · Post by **Roger** » Sun Oct 30, 2022 4:25 am

js1tr3 wrote: ↑Tue Apr 05, 2022 3:31 am Got it apart, once I figured out how the Rosenberger hpk connectors work. Pictures added on the blog.
I was right the little purple lock rings were key. Then simultaneously lifting the four fingers that hold the pins in place. I lifted each the slid a small zip tie into the slot to hold it unlocked.

https://www.rosenberger.com/product/hpk/

Thank you js1tr3 for posting all the info and pics, must have taken a whole lot effort and patience, much appreciated

Small drive unit inverter teardown and repair

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Re: Small drive unit inverter teardown and repair

Re: Small drive unit inverter teardown and repair

Re: Small drive unit inverter teardown and repair

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