Bug/Problem in MC library driving low inductance motors?

jouko.perkkio · ‎2019-09-22

I'm using motor control hardware very close to NUCLEO-G431RB with X-NUCLEO-IHM08M1 3Sh. It has only a bit different bus voltage and current feedback scaling resistors so I was able to spin the motor it with the motor profiler. The results were quite close as measured, RS=0.1 ohm and LS=0.08 mH. So I know that the hardware works.

Now when I configure the parameters in the MC Suite, it results in around 50% constant PWM phase output, exactly same for all U, V and W channels. Which obviously does not make any sense.. At the end there's an oscilloscope picture of U and V running at 10 kHz. Same figure is acquired with 30kHz too.

If I raise the inductance value closer to 1 mH, the PWM starts to get correct shape, but this is too big of an inductance value to make the motor spin, it just does not work. I tried to chase the possible bug/problem/issue where the PWM is configured according to the parameters derived from LS, but this seems to end up in the libmc closed library...

I'm using the latest MC Suite (5.4.1), CubeMX (5.3.0) with SW4STM32 IDE.

Anyone has experienced similar problems? Any workarounds?

jouko.perkkio · ‎2019-09-28

Answering to myself: there was no problem relating to the low inductance. I didn't mention, but the motor is pretty big (rated to 3kW) so I totally underestimated the required rev-up currents. After reconfiguring the startup conditions with MC SDK, the motor started spinning just fine!

By the way, now when the basic setup works for the motor, the on-the-fly motor startup and speed ramps work like a charm. I'd say that the MC SDK makes BLDC motor control pretty easy when the hardware is close to the evaluation boards.

Laurent Ca... · ‎2021-06-27

The question has been moved from the "Motor Control Hardware" section to the "STM32 Motor Control" section (the question is about the STM32 MC SDK).

Best regards

Efigu.1 · ‎2021-11-17

Hi. I have the same issue. X-NUCLEO-IHM08M1 + NUCLEO-F302R8. Motor BLCD 250W 36V 7A - Hall sensor or quadrature encoder (but with sensorless configuaration it works!)

Zq.1 · ‎2023-03-17

Hi. Have you solve the issue with quadrature encoder?

thx!