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VESC 100V 250A - don't reach 50000ERPM

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tobiokanobi
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VESC 100V 250A - don't reach 50000ERPM

Dear VESC supporter and team,

I've bought two VESC 100V/250A, both show on the same motor the same behaviour. I believe it has something to do with my settings:

Goal: Test the Motor Hemotec 135.20; (135kV; 28pole) with props to reach ~3600rpm (3600*14=50400eRPM).

Setup: original setup 2(2x5s in series, each 5000Ah) LiIon Battery each connected to one VESC. Tried also: 3x(2x5s) for a single VESC; sharing ground

Description: FOC Setup works fine. 158A max current for the motor.

Experimental tab: RPM controlled from 1000 to 50000erpm; 100rom steps; 0,25s waiting (to reduce Amp Peaks); increased Max Motor Current to 200A after few tests; increased max battery current to 250A; for testing;

Problem: At around 40000erpm; motor stops suddenly, erratic on off; 

Tried: (more batteries in parallel, but same voltage). 

Tried: Google Digging: FOC-> Advanced Tab: Increase Frequency to 60kHz; disable v0_v7 (was disabled)Hemotec135_20.jpg_FOC.jpg

Tried: Higher Current settings (in  case of current limit)

Current max shown in real time: ~70A, a bit jumpy

Problem still exists.

Has anyone a hint for me, or are 2x5s = 10s simply to low for higher RPMs with a 135kV 

 

Hemotec135_20.jpg

Hemotec_135_20_40000erpm_drop.PNG

Thanks a lot for all hints you can give me!

-Tobias

frank
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You can try to change the observer gain (double or quadruple).

But please try with little amps first and go to RT-Data and look at the FOC Tab, Q currents. When you see bigger ripples stop the test and re-adjust!

Watch: https://cloud.vedder.se/index.php/s/4jgcBKfmPZZqHR3

Please note that the new VESC- tool typically only needs the observer gain to be adjusted. The video was shot using an older Tool and we played with many parameters. This is not needed in your case.

 

 

 

tobiokanobi
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Thanks Feank, will do. Do you recpmmend to leave the Frequency at 60k or to lpwer it back to 30k? Shall the Oberver Type "Ortega Original" be enabled or not?

 

 

Many thanks, Tobias

 

tobiokanobi
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Another question - when recording the Experiment and save it as .csv; there is no header in the file; I tried to guess a little - maybe some of you have a hint? I really appreciate your support :-D

 

VESC_header.PNG

frank
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Try the 30Khz first. 60 is a lot! I would go for 40 first. Don't change any standard values, just change the observer gain.

You can also try to change the time constant T in the Motor FOC. As standard it is 1000uS. If you change it to 500 or 250uS and press CALC APPLY OLD, KP and KI will change accordingly.

 

 

tobiokanobi
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Thanls a lot Frank. Funny as it is, we run now in a current limit at ~130A MC, but the current limits are set to 180A (even for test to 240A)...is there another secret 😁?

 

tobiokanobi
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So topic can be marked as "solved" - Observer from 100 to 200 and T from 1000 to 500 made it happen (with 12s and 14s battery, but 12s is way more efficient).

Thanks Frank!