Shudder on Regen with Tesla Small Drive Unit

[Kitlacey]

Hi All,

I have a strange, occasional problem with my Tesla SDU. I'm in final stages of tweaking and occasionally, after rapid acceleration, I get a shudder on regen as I decelerate. It's not huge, and makes no difference if I'm off pedal regen, or on brake pedal. It also makes no difference what values I use

I've attached the file. If anyone can suggest where to start; it would be appreciated.

[johu]

Looks like Zero EV firmware. It is rather outdated so if you don't need the special features you should consider upgrading to 5.32.R

Apart from that it might be worthwhile to set udcnom to some midrange battery voltage. Regen raises the DC bus voltage so you may be saturating the stator or something. Setting udcnom will compensate for voltage changes

[Kitlacey]

OK, so UDCnom is currently 0, but the nominal battery voltage is 350.4, so I should try setting it to that?

I'm due to finish the project this week so I don't want to mess with anything else at this stage.

[johu]

Yes, try that. You can always revert the change