Jerky car at pull up

[hanstoorman]

(5.35.R on inverter, v2.2 of web interface)

I have some trouble with my SDU rotordir.
The SDU works fine, only sometimes when I start the drive unit the spotvalues 'seldir' and 'rotordir' are opposite. In this case the car is not driving at all, when I press the trottle the car is very jerky. This doesn't stop when I restart the drive unit.

It can only be fixed by waiting 5 minutes and restart again, when I'm lucky the problem is gone...
Does anyone have this problem as wel?

[johu]

Can you attach your parameters please

[hanstoorman]

Here are the params

[johu]

Ok, some comments.
- These parameters aren't from v5.35 because then potmax would be limited to 3500. Read here: viewtopic.php?t=5075
- What is your full battery voltage? You have set udcmax=350V so it will start derating at about 340V

At standstill it is likely that rotordir is opposed to seldir because the direction can only be determined once the rotor is spinning. So I think your problem is not related to that

[hanstoorman]

I have attached the 2 screenshots of the spot values, one is from a godd working SDU and one from a jerky SDU.

When the SDU starts jerking the rotordir and seldir have opposite value, this behaviour is very constant.

[hanstoorman]

Sorry Johannes, you are right about the version, it is v5.34.R-sine

My maximum voltage is 84cells x 4,2V = 353V

[johu]

Are we talking about 2 drive units or one?

[hanstoorman]

One drive unit

[johu]

Ok. When it is jerky can you make a plot of potnom please

[hanstoorman]

Here are two plots with potnom, pot and idc.

[johu]

Ok, so it's not derating.
Can you plot fstat when jerky?

[hanstoorman]

Here is a plot of fstat, idc and potnom

[johu]

Ok, so it's only at slow speed then?

[hanstoorman]

It is not possible to drive, the car only bouncing. When you press the throttle the bouncung gets louder.
When you push the car a bit forward and it starts rolling it is possible to drive bud it drives jerky.

[hanstoorman]

This problem only happens once in the 5 times at starting up the car. The other 4 times there is no problem at all and the car drives smoothly

[hanstoorman]

Is it possible with my hardware to downgrade to 5.13.R-sine? I have more experience with this firmware version.

[johu]

Yes
Would be interesting to see if that fixes it and in which version it reappears

[hanstoorman]

I tried 3 different firmware versions: v5.35_r_sine, v5.32_r_sine and v5.27_r_sine, same problem.

During the last firmware update by accident the 12V to the SDU was disconnected, now I can't connect to the board again.....

Is there a way to connect to the board again with CAN and upload a new firmware version?

[johu]

now I can't connect to the board again

the wifi it not there or you just don't see parameters? If the latter just re-run the update
Otherwise get can-updater.py here https://github.com/jsphuebner/stm32-CANBootloader
Of course that needs some CAN adapter to be set up

[hanstoorman]

Thanks, I re-run the updater and it works again

I also found the jerking problem!!!
The handbrake of one wheel got stuck. After fixing the brake it all works

Thanks Johannes for your responses and help.

[johu]

ABC always blame car

[hanstoorman]

Hahaha, you are right

Is it possible to change the topic name to jerky car problems, it makes more sense then rotordir problem

[johu]

Just edit your entry post, there you can change the title

[hanstoorman]

the handbrake was unfortunately not the problem, the inverter was defective. probably got too hot and therefore 1 or 2 phases failed. With a new inverter it drives smoothly again