Grin V4 Baserunner L10 Noisy Motor

[spooknik]

I retrofitted a stock eBike (SCO brand) with a CA3 and V4 Baserunner a few years ago. It's been running very well for me, however ever since changing the motor has been very noisy. With the stock motor controller it was mostly silent. The motor was set up using the autotune function in Phaserunner Suite (photo attached)

The bike has a Shengyi CMT03E mid motor, here is the datasheet and the product page.

And a video of the motor noise.

Any thoughts or ideas? The noise is driving me and my neighbors a bit crazy.

 

[amberwolf]

The first thing I'd try is change from hall sensor start and sensorless run, and force it to always use hall sensors, just to see if it changes things.

You may also need to decrease phase currents, or motor power limits, depending on what the system used when it was quiet. (i'ts possble that higher phase currents could induce greater physical vibration).

You can play with the motor settings that autotune detected; they're not always quite right. tiny changes at any one time are safest.

After that, you might try the feedback bandwidth tuning section, first noting present values and changing one thing at a time, just a little bit, to see if it helps or makes things worse, then either continue pushing that or go back to what it was, etc.

If it's a freewheeling motor that doesn't do regen, you might want to turn off the regen phase current.

Also, if it's a really high RPM motor, especially with a high pole count, it might just not run well with this controller--it might have too many transitions for it to keep up with, too high an ERPM.

 

[slaphappygamer]

I’m leaning towards your motor is trying to regen. Change your Max Regen (start) to 45 and Max Regen (end) to 47. Your 36v battery will never reach these values and Max Regen will never be achieved. Hopefully that’ll clear the fault.

Could also be an issue with feedback tuning, but the motor would sound more jittery and would stutter. I would look at regen and try to resolve the regen fault.

Also unsure about magnet pole pairs. There is no reference on the motor product page.

 

[spooknik]

The first thing I'd try is change from hall sensor start and sensorless run, and force it to always use hall sensors, just to see if it changes things.

You may also need to decrease phase currents, or motor power limits, depending on what the system used when it was quiet. (i'ts possble that higher phase currents could induce greater physical vibration).

You can play with the motor settings that autotune detected; they're not always quite right. tiny changes at any one time are safest.

After that, you might try the feedback bandwidth tuning section, first noting present values and changing one thing at a time, just a little bit, to see if it helps or makes things worse, then either continue pushing that or go back to what it was, etc.

If it's a freewheeling motor that doesn't do regen, you might want to turn off the regen phase current.

Also, if it's a really high RPM motor, especially with a high pole count, it might just not run well with this controller--it might have too many transitions for it to keep up with, too high an ERPM.

So far the following have not helped:

1. Changing to only hall sensors (no fallback to sensorless)
2. Phase current can't be any lower than 30A in the suite, I tried raising it a bit as well.
3. Setting Max power to 250W and 100W (just for the sake of trying)
4. Around 2.81 RPM/V seems to be right for this motor. Around 3.5 it starts to spin really fast during the spinning test.
   • My math:
   • KV = 90 RPM ÷ 36V = 2.5 RPM/V.
   • If gear ratio included then: True RPM = 90 × 31.1 (gear ratio) = 2,799 RPM. KV = 2,799 RPM ÷ 36V = 77.75 RPM/V.
   • But 77.75 RPM/V is a crazy number right?
5. Trial and errored all of the variables in feedback bandwidth tuning section, really not much effect for the noise.
6. Turned off regen by raising Regen voltages above the battery pack's voltage (per slaphappygamer)

Would the Rs or Ls values be worth changing?

Current settings:

 

[spooknik]

I’m leaning towards your motor is trying to regen. Change your Max Regen (start) to 45 and Max Regen (end) to 47. Your 36v battery will never reach these values and Max Regen will never be achieved. Hopefully that’ll clear the fault.

Could also be an issue with feedback tuning, but the motor would sound more jittery and would stutter. I would look at regen and try to resolve the regen fault.

Also unsure about magnet pole pairs. There is no reference on the motor product page.

Thanks for the suggestion, but raising the Max Regen voltages to 45 and 47 didn't help (see my settings above).

Motor has 16 poles so 8 pole pairs. Best I can figure it: pole pairs = 8 × 31.1 (gear ratio) = 248.8

 

[neptronix]

This drive has two reduction gears, doesn't it?
Plus a decent pole count on top..
If so..
You may be running against the electrical RPM limit of the phaserunner/baserunners.. it's possible to hit these limits with a MAC geared hub motor, which is 16 poles + a 5:1 reduction.

Good luck tuning, but you might end up with a high eRPM capable controller like a VESC if tuning fails to produce results..

 

[slaphappygamer]

Looks like you are no longer getting the regen fault you previously had. Thats a good start.

Did you run autotune after changing the Pole Pair count? Your torque (per phase current) seems off.

 

[spooknik]

This drive has two reduction gears, doesn't it?
Plus a decent pole count on top..
If so..
You may be running against the electrical RPM limit of the phaserunner/baserunners.. it's possible to hit these limits with a MAC geared hub motor, which is 16 poles + a 5:1 reduction.

Good luck tuning, but you might end up with a high eRPM capable controller like a VESC if tuning fails to produce results..

Yea, it has two reduction greats. Gear ratio is 1:31.1. So 249 pole pairs, which yea might be too much for the baserunner.

Pretty easy to swap in a VESC controller coming from a baserunner? My Baserunner fits so perfectly under my down tube battery, guess I'll have to give that up.

 

[spooknik]

Looks like you are no longer getting the regen fault you previously had. Thats a good start.

Did you run autotune after changing the Pole Pair count? Your torque (per phase current) seems off.

Yea I ran the auto-tune after updating the pole pair count. It didn't seem to touch Max Phase Current during the auto-tune. I bumped it up to 45A and the noise is still there.