justin_le said:
Just checking in, have you had any more luck with this? After you autotune the phase impedance (Ls and Rs ), then it's really important to have the #poles and RPM parameters set correctly. The RPM is nominally referring to the speed that the motor spins at at the "rated voltage", which we've preshipped with them set to a 60V system rating. If you have a motor with say 16 pole pairs and a 4:1 gear reduction ratio, it's important to put a #pole pairs value of 64 in this case, rather than 16. From my records I have that the Cute Q100 motors was between 64-65 effective poles.
I really appreciate your efforts, thanks so much. I shamefully admit, I've been continually failing at this seemingly simple task.
If I understand you correctly, then maybe I should use 16(poles) multiplied by 12.6(reduction ratio of a Q100) and place 201.6 in poles instead of 16? I feel like I am misunderstanding something here, when you say 64-65 poles, where does this number come from?
On page 42 of the manual there is a flow chart, it says "Have 3 repeatable measurements been made?" For much of my previous attempts to use the autotune for the Ls and Rs measurements, the numbers can at come in pretty wild ranges much of the time. What qualifies as 'repeatable measurements'? If say I get 74-110 for the Ls, should I use the average, what I see most often or wait until I see something very close (103, 104, 102 for the three measurements) and use something closer to that? I don't know how important these numbers are in terms of accuracy, but I am sure there is some logic that would be better to use over another.
justin_le said:
If you aren't totally sure of the RPM/Volt, then use a best guess for the RPM at 60V and it should still spin up fine. When you run it while plugged into the computer, you'll see your motor rpm on display in the BacDoor software, divide this by your battery voltage to get the RPM/V, then multiply it by 60V to get the "motor rpm" parameter at our 60V system voltage.
The motor is rated for 201rpm at 36v. I divided 60 by 36 and get 1.67 and then multiply 1.67 by 201 to find the motor RPM at 60V, which would be 335.67. I don't know how much the rated RPM value accuracy matters, but my hot off the charger voltage is 58.4 and I usually have seen my battery packs running around 53v, perhaps it would make more sense for me to use 302 RPM, but maybe I don't really understand how this number influences the controller.
Without your information about changing the pole count to 64-65(from 16) and changing the motor RPM to 335(from 201), the motor was painfully jerky and the whole process of programming the controller went wrong.
With these changes, this q100 runs and sounds wildly better. I am sure these changes are obvious to some, but I may not have ever figured this out otherwise.
I've played a little bit with the hall offset and Kv tuning per the manual. I haven't seen any mention of this but the manual seems like it's necessary. Should I simply follow the manual on this?
I imagine with this information in mind, I may be able to gain much more success with a Q75 (sensorless geared) as well. Sorry for writing so much. Thanks!