ESC32 "kicks"

[Trnquill]

I'm building an AutoQuad hex and I'm using ESC32's. I got one arm assembled today and tried how one ESC works with DualSky XM5010TE-4 motor. The motor spooled up fine and ran really smooth even on very low RPM but when I cranked the throttle up it started "kicking". Almost like the ESC applied really heavy brakes for fraction of a second once every second or so, quite randomly. First the kicks were really seldom and quite soft (yet very noticeable), when I gave more throttle they became more violent and more frequent. When at or near full throttle the sound is like crackling! What's going on?

I tried with second motor and it was just the same. I haven't yet tried with another ESC to see if it is any different.

I have not flashed the ESC. All I did was solder on bullet connectors and pin headers and the 5V jumper. I was driving the ESC with a HobbyKing servo tester (the red one) powered by a BEC. The BEC and the ESC was fed off a 4S battery pack. ESC sits right next to the motor at end of the boom. I have approximately 40cm power and PWM wires running through the boom to the ESC. Both the power and PWM wires are tightly twisted (not together but separately). I have three 470uF 35V PANASONIC CE FM caps installed parallel to main power tabs of the ESC, right next to the ESC.

Any idea or experience on such behaviour? What is causing it and will flashing new firmware help? I have never seen any ESC do such a thing!

[chschmid]

Try something:
take the signal wire out of your boom and try again. If the sound is gone, the powerline disturbs your signal. With a shielded signal wire, your problem would be solved then.

Otherwise you might play with advance and switching frequency.

Just my 2 cents.

Cheers
Christof

[Trnquill]

I actually ran the system on table before putting things inside the boom and the wires were separated with good distance. The motor/ESC behaved exactly the same. But I will try pulling the power wires out of the boom and see if that helps, thanks!

Here's a short vid demonstrating the problem. You can hear and see the kicks when I'm at half throttle. Near full throttle the kicks are so common it starts to make a rattle sound.


Current limiter? Switching frequency? I thought I read somewhere the ESC32's are ready to use right out of the box. Just solder some wires on and go. I will update the firmware and try the RPM mode at later point but for now all I want to find out is if my ESC is faulty or what on earth is going on.

If and when I get things rolling I'll show some more detailed pics of my system. As you can (hardly) see in the video, I have 3D printed a mounting bracket/box/enclosure/airduct for ESC32 and its heat sinks. I have the three capacitors sitting under the ESC in a bracket, enjoying the same air flow that travels through the cooling fins.

[Jdmagoo]

Video is private

[Trnquill]

Sorry, it's now available! Thanks!

Had some trouble uploading the vid from my cell phone. It said "upload failed" but still the video showed up in my library. Looks like it failed to save the settings even though the upload was successful.

[bn999]

What RPM are you getting to? The MIN_PERIOD may need to be reduced slightly, especially since it looks like a very high pole count motor. If that's the problem, it should not happen under load since the RPM will be much lower.

If you hook up a serial line and watch the telemetry as you are running, you can see what the zc period is at high throttle.

[bluuu]

there is 24 magnet poles ?

[Trnquill]

[Trnquill]

Ok, flashed the firmware and things got a bit better. The "kicks" come in later and last lesser range of PWM. Also the rattling at high PWM & RPM got less obvious. Looking at the settings it seems like the default Advance setting got lowered from 15 to 10 when updating the firmware. This made experiment with even lower Advance settings. Setting the Advance to 5 make the kicks go away completely, but the rattle at high RPM remained. I lowered Advance to 0 (or 0.10 as it turned out when reading the settings back after writing) and the rattle was almost gone, too. However, the motor actually dropped its RPM when going past the throttle PWM value where the rattle usually started. Both the motor and ESC32 fets got really hot really fast so I ran only short 10 second test with this setting.

I also experimented with Switch frequenz. It is at 20 by default and first I decided to lower it. Value of 8 made the motor hardly turn at all, it rotated slowly and rattled a lot! The FETs on ESC32 got extremely hot in few seconds so I pulled the plug. Going higher on Switch frequenz doesn't seem to do anything as far as the kicks and rattles go. I experimented with 30 and 40 but couldn't notice any difference compared to the default value of 20.

Any ideas, what should I try next?

[Trnquill]