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Configuration of a 2Kg Outrunner Predator 37/6 RC Motor

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electricfox
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Configuration of a 2Kg Outrunner Predator 37/6 RC Motor

I am testing a Predator 37/6 Motor on an Vesc 75/300 with a 28x14 propeller reaching 200 Phaseamps with a 16S Li ion battery without problems. 

 

The motor is a 2kg sensorless Outrunner 170KV used for RC planes. I am using it in current control in beta fw from 27.06.2021

In detection it suggested 250A. In general the motor is capable of 15KW peak. So in theory I should reach more than 7KW as now.

Going on higher currents than 200A makes Absolut Overcurrent Faults at 50-60% duty cycle on 48-54000ERPM. ABS Overcurrent Max is set to 280A at the moment. 300A as value didn´t help and I don´t want to go much higher not to burn the Vesc.

When doing the detection I get different values for inductance of 1,07- 2,2uH. Other values stay the same, even when the motor is cold or warm.

A LCR Meter for better L values is on its way. As I read that measurement of L value on such motors might be not perfect with the Vesc.

I already tried:

-Detection several times

-500ms, 1000ms and 2000ms time constant for calculating Current KP and Current KI

-Switching frequency 60khz instead of 40khz

 

When the motor is running it does not get hot, max was about 55 degrees celsius.

I want to understand what exactly happens and what I can change to not go into ABS Overcurrent Faults.

So maybe someone can can explain the behaviour to me?

Here I have some bug triggered data and csv files:

https://drive.google.com/drive/folders/17kHEDRCybqKBftmRF6IV3MMOQv4LswKg?usp=sharing

I wanted to open the sampled data csv files, but when opening in Log Analysis tab I can´t see anything in Sampled data tab. Is there a trick?

Thanks for your help!

IMG_7359.jpegIMG_7358.jpeg

vadicus
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ABS means bad FOC settings most of the time.

Isn't measured inductance suspiciously too low? What about other measured parameters?

I would also reduce the frequency to about 5khz during the detection and test with those detected parameters.

 

 

 

NextGen FOC High voltage 144v/34s, 30kw (https://vesc-project.com/node/1477)

electricfox
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Thank you Vadicus, you were right!

Without reading your post I did some more testing and  increased Inductance to 2,9uH. So now I can reach 260 Phaseamps over a long period without problems. But I also had to rise ABS Overcurrent Max to 350 A. I also tried 30KHZ,50KHZ and 60kHZ which didn’t work better. Values inbetween will be tested soon. Doubling Current KP or/and Current KI also didn’t help. V0 to V7 at 30KHZ made no difference. 

I made some more sampled data pictures when ABS Overcurrent Fault occurs. They look all the same. Any idea?

IMG_7387.jpg

vadicus
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Also, try to reduce the gain. Changing flux value slightly (1-2 up or down) made a difference in my case. 

 

 

 

NextGen FOC High voltage 144v/34s, 30kw (https://vesc-project.com/node/1477)

electricfox
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I got an LCR meter which was the solution for my abs_overcurrent faults. Inductance is now 3,92uH. I also doubled the Oberserver Gain. Now I am able to push 400 Phaseamps with a 13S battery at around 11KW. 400A Phaseamps are the limit of the default firmware. When changing to the NO HW LIMITS Firmware it did not use the 420A Phase I changed in Vesc-tool, which looks like a bug in beta fw from 27.06.2021. There is no other llimitation. I updated my data in the link of my first post.

PBR-Automatyka
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Olivier is very valuable information. What measurement frequency did you use when measuring inductance?

electricfox
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Witam :)

I measured at 100kHZ like Benjamin Vedder is doing in his YouTube videos :)