LAUNCHXL-F28027F: Instaspin FOC motor identification very rough

Michael Mätzler

Hi folks,

Since a week I am trying to get my motors run smooth.

I am using lab_2b and can finish the identifying the motor but it`s running very rough and uses a lot of current (approx. 700mA) with no load attached.

Just matched the voltage in the user.h to 16V (4S LiPo) and the Motor_Frequency to 1114.6 (16V*380rpm/V /60s *11Polepairs) and the Motor_Voltage to 25.2V (6S LiPo). Further I have selected my own Motor in the file and added the datasheet values according to the instructions. Haven`t done any other changes to the project.

Does someone got an idea why my motor isn`t running as smooth as Instaspin normally does? It`s driving me crazy..

My Setup is:

-4S LiPo

-F28027F

-DRV8305

-380KV 22Pole Outrunner (https://hobbyking.com/en_us/4108-380kv-turnigy-multistar-22-pole-brushless-multi-rotor-motor-with-extra-long-leads.html

over 8 years ago

0 Han Zhang6 over 8 years ago

TI__Expert 7835 points

The motor you are running has fairly low inductance. Please try to run the motor identification with lab2c. Thanks.

Han

0 Michael Mätzler over 8 years ago in reply to Han Zhang6

Intellectual 320 points

Thanks for your answer. Just tried lab2c but the result is nearly the same. While estimating motor flux it is running very smooth but as it starts searching for ls-d its very rough again.

Probably there is some useful information in the gui itself for you?

0 Michael Mätzler over 8 years ago in reply to Michael Mätzler

Intellectual 320 points

Hi again,

the motor is running pretty smooth if I reduce the USER_MOTOR_MAX_CURRENT from the rated 17A (in my application even more because there is just a pulsed power on the motor) down to 5A. But as a conclusion it has no power at all.

Does somebody got an idea what possible could be wrong?

Best regards,

Michael

0 Han Zhang6 over 8 years ago in reply to Michael Mätzler

TI__Expert 7835 points

Hi Micheal,

Can you please share the custom motor setting section of your user.h file. Since you have a low inductance motor, you could consider to increase the USER_MOTOR_FLUX_EST_FREQ_Hz to up to 100 for better estimation performance. Thanks.

Han

0 Michael Mätzler over 8 years ago in reply to Han Zhang6

Intellectual 320 points

Hi Han,

I am already using 120Hz for USER_MOTOR_FLUX_EST_FREQ_Hz - with no change in the result.

The solution for my problem was to attach the flywheel already at the identification. It seems that the motor was too powerful for its low inertia.

Thank you all very much!

Michael

C2000™︎ microcontrollers

C2000 microcontrollers forum

LAUNCHXL-F28027F: Instaspin FOC motor identification very rough