Dyno Tuning LDU

[MrMoparMan]

Hello, I am looking for some advice from the experts, beyond the already terrific information on this forum.

I have a newly running build and I am feeling my way through the settings. My dyno guy from my Turbo builds has offered me a free dyno day so we can learn the Inverter tuning.

I would like to approach the session with a solid plan on what to tune first, second, and so on. Any advise would be very much appreciated, thanks in advance.

The car is a 4000lb + 1972 Plymouth Satellite
LDU Sport motor with Zero EV control board
100 kWh Tesla Battery pack
Orion 2 BMS

So far the car makes decent power but I would like to safely maximize the potential with some fine tuning.

I look forward to sharing all the results and hopefully have a good base tune for similar builds.

https://photos.google.com/u/0/photo/AF1 ... 7oZlMb5xMp
https://photos.google.com/u/0/photo/AF1 ... NYXIXEvd6b

[jon volk]

What are your current parameters?

[MrMoparMan]

Thanks for the reply Jon, great question...I should have included this.

I am happy with the slow speed manners, very smooth, no jerkyness.

Regen using just brake switch is great, fits my drive style.

"Launch Control" Holding brake and full throttle is good initially but then cuts and powers and cuts and so on.

Full throttle at speeds above 40 mph seems to consistently pull with out a power cut.

[jon volk]

The parameters look pretty good. I’m not 100% on what you’re referring to with cutting power but it sounds like it’s tagging a derating limit. Zero has custom firmware so I can’t tell you what values like roadspeed gain might be affecting. If it cuts power perhaps it gives a de-rate error that will tell you what’s going on. Could perhaps raise IDC max to 1200-1300 and see if it goes away.

[MrMoparMan]

Ok, I'll try the IDC change.

Not really sure how to describe the power cut, it's like I lift and floor it and lift and floor it.

I'll try to log some of the parameters.

Thanks for your input!

[Isaac96]

I had similar issues when my Tesla inverter was overheating due to large quantities of air in the loop - it would hit the temperature limit and shut off, then come back on quickly. Might be helpful to take a look at the motor and inverter temps, see if they rise quickly on power?

[MrMoparMan]

Funny you mention that, I just went out today to watch the temps after Chris from Zero mentioned motor temp.

DU temps started at 28C, didn't get further than that...

I did one Brake on full throttle launch with the attached settings, The car had good traction, and pulled hard all the way to 50 or 60 MPH when I let off. After coasting for a few seconds, I heard the Pyro Fuse blow.

I got the car home, checked for any shorts, there are none. I put a jumper wire across the fuse and powered the car. Everything powers fine, but I get an Overcurrent fault as soon as I switch to forward or reverse.

I assume something went wrong in the inverter.

[Isaac96]

Yup, that would be a blown inverter phase. Blowing while coasting -- that's really weird.

[muehlpower]

What happens if udcmax exceeds the set 410V during recuperation? Does the controller disconnect the maincontactor?

[jon volk]

Curious to hear what you find. I would doubt a blown igbt alone can pull enough current to blow the pyro fuse. I would think it requires a direct short somewhere.

[MrMoparMan]

Curious to hear what you find. I would doubt a blown igbt alone can pull enough current to blow the pyro fuse. I would think it requires a direct short somewhere.

I am curious as well, No indication of any short right now, all high voltage components run normal except when selecting fwd/rev.
Any idea on what settings I may have messed up to cause the problem, or is it just something that an happen?

Yup, that would be a blown inverter phase. Blowing while coasting -- that's really weird.

I thought so too, I was expecting a hard short to blow the fuse. I patched it with some 8 ga wire to test and everything powers up fine.

[MrMoparMan]

What happens if udcmax exceeds the set 410V during recuperation? Does the controller disconnect the maincontactor?

Not quite sure

[MrMoparMan]

Found the smoke.

I have probably 1000 miles on the car with lots of hard acceleration. Not sure what would cause the Tesla pyro fuse to blow, it was power off regen at the time, battery cells were about 4.05 max.

Here is a picture of the inverter, the bottom phase took hit. Do you guys think this is due to the fuse blowing?

https://photos.google.com/u/0/photo/AF1 ... LexJhtllH4

[Jack Bauer]

How are your contactors controlled?

[tom91]

Here is a picture of the inverter, the bottom phase took hit. Do you guys think this is due to the fuse blowing?

If a LDU is spinning when the fuse blows or contactor drops out there is a large chance of irreversible damage.

[jon volk]

Photos not working for anyone else?

[MrMoparMan]

How are your contactors controlled?

Ignition on powers the pre-charge contactor, and then the DU closes the main contactor with start switch input. The BMS can shut down the ignition/DU power and contactor but it would be a total car shut down which did not happen in this case.

[MrMoparMan]

Photos not working for anyone else?

It's probably me...Let me see if I can figure out a better way to attach them.

[jon volk]

Holy shit. That certainly looks like enough to blow a pyro fuse.

[MrMoparMan]

If a LDU is spinning when the fuse blows or contactor drops out there is a large chance of irreversible damage.

That looks to be the case...

I think using a used Tesla pyro fuse was a bad idea. It blew at a strange time for not having any indication of a short.

[MrMoparMan]

Holy shit. That certainly looks like enough to blow a pyro fuse.

So going forward, I would like to prevent this from happening.

Hopefully I can pinpoint the failure.

[muehlpower]

I'm not very familiar with the fuse system from the tesla S. The model 3 has only one fuse, the model S apparently has a pyrofuse and a normal fuse. I think the pyrofuse is normally only triggered in the event of a crash. There are fuses on the internet for the Model S with 450A, 550A and 630A. What kind of fuse system do you have and do you actually control the pyrofuse?

[MrMoparMan]

I'm not very familiar with the fuse system from the tesla S. The model 3 has only one fuse, the model S apparently has a pyrofuse and a normal fuse. I think the pyrofuse is normally only triggered in the event of a crash. There are fuses on the internet for the Model S with 450A, 550A and 630A. What kind of fuse system do you have and do you actually control the pyrofuse?

As far as I know, Tesla developed the pyro fuse when they started blowing conventional fuses as they increased power.

So it could have possibly been a failed experiment with the fuse. It is a self contained fuse that senses current and is supposed to blow at 2000 amps. It has an airbag like charge to do the work when it decides to go, so it is quick. It was the only main fuse in my system. I will be using a conventional fuse going forward.

[muehlpower]

Thanks for the reply Jon, great question...I should have included this.

I am happy with the slow speed manners, very smooth, no jerkyness.

Regen using just brake switch is great, fits my drive style.

"Launch Control" Holding brake and full throttle is good initially but then cuts and powers and cuts and so on.

Full throttle at speeds above 40 mph seems to consistently pull with out a power cut.

You say you only regenerate when the brake is applied. When it failed, you didn't brake, right. Could it be that the voltage in the inverter rises to a value that is sufficient to destroy the ITGBs because nothing is diverted into the battery?

[MrMoparMan]

You say you only regenerate when the brake is applied. When it failed, you didn't brake, right. Could it be that the voltage in the inverter rises to a value that is sufficient to destroy the ITGBs because nothing is diverted into the battery?

I did a full throttle acceleration for a few seconds, then I let off and it does have a mild throttle-off regen. I may have also applied brakes which is slightly more aggressive regen. The fuse blew a few seconds after letting off of the throttle, so there was regen at the time.

It is something I would like to get to the bottom of, did my settings have something to do with it? Is it unable to handle full throttle, followed by immediate regen? Or did the pyro fuse blow when it should not have?