openinverter forum

Hi all,

We have an SDU in a VW T2. We've used several of these with success using Zero EV's inverter settings. We're now using an Open inverter board so I'm copying a lot of settings from my previous Zero EV boards to this one. Everything is working great except setting off from 0RPM. At present, I slowly press the throttle until it reaches 30% travel (my regen limit) and then the SDU jumps us forwards into motion. Once it's moving, it drives great, but setting off is scary and a little uncomfortable. The inverter temp doesn't love me for it, and slow manoeuvers in reverse are nearly impossible.

Any suggestion what figures to adjust? I can supply full parameters if necessary, I just wondered if someone knows the magic bullet!

Kit

AAP - Always attach parameters

Sounds like ampmin too high

Almost definitely ampmin or boost are too high. Post parameters and we can comment more accurately.

here you go!

johu wrote: ↑Thu Sep 07, 2023 6:33 pm AAP - Always attach parameters

Sounds like ampmin too high

AMPMIN was 5 so I lowered it to 4
BOOST was 2900 so I oput that back to the 2200 default.

The Jump is a little better after that, but the acceleration now feels very sluggish

At least for me the parameters don't look suspicious. Anyone?
Is your throttle signal all nice and linear?

Yes, it's a new 0-5v variable pedal so it's all very smooth

johu wrote: ↑Sun Sep 10, 2023 6:51 pm At least for me the parameters don't look suspicious. Anyone?
Is your throttle signal all nice and linear?

For what it's worth, I believe everyone suffers with "jumpy" start on the SDU. It's one of the primary reasons I created my fork, and I believe a major reason why ZeroEV stopped using this drive unit. I spend weeks tuning the SDU so you might want to try these parameters to see how it compares:

boost: 3200
fweak: 230
ampmin: 0
fslipmin: 1.50

It's also worth noting that the throttle dead zone makes this "feel" worse, because your foot isn't used to finding the zero point. I don't use regen so my throttle doesn't have the 30% deadzone, and I found that made the experience quite a bit better.

Is it possible to create a plot which shows the throttle and the torque for some seconds while the "jumpy start"?

catphish wrote: ↑Thu Sep 14, 2023 8:07 pm
It's also worth noting that the throttle dead zone makes this "feel" worse, because your foot isn't used to finding the zero point. I don't use regen so my throttle doesn't have the 30% deadzone, and I found that made the experience quite a bit better.

uhi22, tom91, I and others have discussed the "dead zone" problem here.

viewtopic.php?p=60101#p60101

Maybe it's time to implement something like this in the firmware.

Could you please share your successful parameters? Tuning an SDU on my T2 as well.