ESC32 V3 u7 420

Info and Discussion about the ESC32 hardware and software

ESC32 V3 u7 420

Postby richardpos » Sat Jan 02, 2016 11:00 pm

Hi

Happy new year everyone.

I'm having a bit of trouble trying to calibrate esc v3 with Tiger Motor U7 420kv. So far, each calibration is failing due to overcurrent at around 62% duty. I'm not sure if I'm doing something wrong or these motors are just too hungry for these esc's.

I've set max current to 40amps as this is around the current draw at 100% throttle (I'm aware the motor will draw much more than this during high demand but, as duty is only increase by 2% during cal then I shouldn't see a massive overcurrent??).

I've tried different timing advance from 5 degrees to 30 degrees and switch frequency from 12khz to 64khz. All result in overcurrent between 50-68% duty.

Just before the point of overcurrent I'm seeing around 14 amps give or take depending on settings. Over current reads in the 100's of amps +.

Is the current limiter active in the v3 during rpm to voltage cal? I've run the current limiter cal (not required for the v3) and I see max current (40 amps) is reached during the 10-60% duty cycle jump. The cal then continues to 100% while limiting to 40 amps. It seems strange a 2% duty cycle during RPM-voltage cal creates such a high current surge.

FET temps are all below 30 degrees C except my caps hit 80 C during current limiter cal. :shock:

I'm pretty sure I'm missing something here so any help will be much appreciated.

I'm going to run through everything again on Monday so will post all results.

Thanks Richard
richardpos
 
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Re: ESC32 V3 u7 420

Postby Max » Sun Jan 03, 2016 6:47 am

Hi Richard, welcome to the forums.

I don't have any experience with that motor so can only suggest you post some more information.

What prop are you using?

Could you post the ESC32 settings (saved to file) here? Whatever seems to work "best" so far, I understand you're trying some different settings to get this going. Perhaps a corresponding R2V calibration run log might be helpful as well, if you have that. Oh, I'm assuming you're using the ESC Config Utility (not QGC or command-line tools)?

Do you have an external way to verify voltage and current draw (volt/amp meter)? 100s of amps sounds strange to me. What logging rate are you using, and are you connecting via USB or UART port?

You can finish a CL calibration OK, all the way to the last jump of 95-100%? What's the current draw reported around 100%?

Current limiter should not be active during calibration runs. The cal routines specifically set MAX_CURRENT to zero before running the tests (and then resets it back to original value afterwards). It is unlikely but possible that this steps fails, but in this case ECU should cancel the calibration run entirely.

Another thing to try would be running the motor manually from the Telemetry screen of ECU and seeing if you can recreate the issue while logging telemetry values.

Cheers,
-Max
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Re: ESC32 V3 u7 420

Postby richardpos » Tue Jan 05, 2016 7:30 pm

Hi Max

Thanks for your help

Firstly my set up is as follows

ESC V3 with 3 x 50v 330uF caps in parallel and 600mm 14awg wire to battery (will be upping to 12awg as soon as it arrives)
Tiger motor U7 420kv
Tiger motor 18"x6.1" carbon prop
16000mah 6S lipo
Windows 10 running ESC config utility v1.0.0
flyduino UART (usb won't work with windows 10. Driver won't support win 10)
Timing advance 16 degrees
Switch frequency 20Khz
(my timing and advance are going to change its just mid range to get this going. Once working I'll make some adjustments)

Firstly as you suggested I've run the motor up in telemetry mode. The motor spooled up well throughout the full duty range. Current readings in the config utility are around 37 amps at 100% duty. I've placed an FrSky current sensor on the battery lead which was reading around 40 amps (purely for indication only as I'm not sure of the sample rate or accuracy). So i'm confident the ESC and motor combo work well together. There's no sink issues and temps are very low.

So now I try R2V calibration again. First attempt actually ran to 90% duty when the current limiter kicked in at 40 amps(I had set the limit to 40). Is this meant to happen or does it set to zero for cal?

I tried many more calibration runs after this which all failed due to apparent overcurrent and esc error. The separate current sensor showed no overcurrent. I decided to try a new ESC which resulted in exactly the same behaviour (motor running fine in telemetry mode but fails every cal).

I'm beginning to think it may be an issue with windows 10 and the UART. I'm gonna rob the wifes mac tomorrow and try over usb.

I'll post the logs later tonight once I've figured out how to do it properly.

Thanks
Rich
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Re: ESC32 V3 u7 420

Postby Max » Tue Jan 05, 2016 8:24 pm

Hi Rich,

Since you're using the UART, try lowering the Telemetry Rate setting (http://autoquad.org/wiki/wiki/aq-esc32/ ... -Functions). Try low like 50Hz or 100Hz to test the theory... if that works you can try faster rates, although it most likely won't affect the calibration results very much, if at all.

I don't have a Win 10 box for testing yet (soon!), so I'm not sure what is up with the USB driver. STMicro aren't always very good about drivers, that's for sure.

If Flyduino adapters are still using SiLabs CP210x chips, that could also be a problem... their drivers are (sometimes?) also crap. I stopped using my SL-based adapters and only use FTDI-based ones now == fewer problems.

You could be right about this being a Win 10/driver/USB chipset issue. Will be curious to see if the Mac yields better results.

-Max
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Re: ESC32 V3 u7 420

Postby richardpos » Wed Jan 06, 2016 6:29 pm

Hi Max

Success!

Looks like the problem is with either win10 and/or the flyduino UART.

I ran the R2V cal 3 times using the mac and USB with no issues.

So i've only tested with standard settings but will start to make some adjustments now.

Below are the settings

ACTIVE_FREEWHEEL 1
ADVANCE 16
AUDIO_VOLUME 0
BAD_DETECTS_DISARM 32
BAUD_RATE 230400
DIRECTION 1
ESC_ID 0
FF1TERM 0
FF2TERM 0
GOOD_DETECTS_START 48
ITERM 0.005
MAX_CURRENT 45
MAX_PERIOD 12000
MIN_PERIOD 50
MOTOR_POLES 14
PTERM 0.5
PWM_HI_VALUE 1950
PWM_LO_VALUE 1000
PWM_MAX_PERIOD 25000
PWM_MAX_VALUE 2250
PWM_MIN_PERIOD 2200
PWM_MIN_START 1100
PWM_MIN_VALUE 750
PWM_RPM_SCALE 6000
RPM_MEAS_LP 0.75
SERVO_D 0
SERVO_DUTY 5
SERVO_MAX_RATE 1000
SERVO_P 0.05
SERVO_SCALE 360
STARTUP_MODE 0
START_CURRENT 0.75
START_VOLTAGE 0.75
SWITCH_FREQ 20
THR1TERM 0
THR2TERM 1

And heres the R2V plot

Image

ESC temps reached around 40 C

I'd set max current to 45 amps which was reached at about 90% duty. Hence the cluster of plots at the end of the chart. Thrust was around 4750g at 90% duty. Will post a thrust plot later this week

Will be trying 8S next so will post these results also.

Many thanks for your help

Rich
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Re: ESC32 V3 u7 420

Postby LPR » Wed Jan 06, 2016 9:46 pm

Rich

Be careful when trying 8s lipos with the U7. The U7 is only rated for 25 Volts or 7s lipos. I've always for found that going over the rated voltage causes extra heat while developing the same thrust as with rated voltage.

Larry
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Re: ESC32 V3 u7 420

Postby richardpos » Wed Jan 06, 2016 10:35 pm

Hi Larry

Thanks for the heads up. The specs claim 8s is possible but I take it its not advisable? I tested the U5s at 8S which produced 4.1kgs of thrust at 24 amps with 15" props. The thrust at 6s is around 2.5kgs. I didn't notice excess heat but the motor was not run for a long period so I will re test.

Thanks
Rich
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Re: ESC32 V3 u7 420

Postby LPR » Wed Jan 06, 2016 11:55 pm

Rich

The specs I read only went up to 25 volts for the U7 420kv and at that voltage you should use 1187.5 watts with 5060 grams of thrust if your using the 18 x 6 prop.

I've run a U8 using a 29" prop with A 11s lipo but only for testing and not more than a minute.

You can test with 8s but take care not to get the motor too hot. You well need a good heat sink on the ESC32 V3.

Larry
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