Motor startup in sensored mode

[JandreFrey]

Hi everyone

[PN]: STM32F303RE, X-Nucleo IHM17M1, Faulhaber 0620-006B
[VERSION]: 6.4.1
[TOOL]: MC Workbench setup
[DETAILS]: Hi everyone. I'm currently trying to configure the aforementioned hardware for motor control. My question is in regard with sensored startup. In sensorless mode, the open loop motor startup is configured in the "sensorless startup parameters" window in "Speed sensing config" settings. However, when in sensored mode (hall effect), there is no option to do configure the startup behaviour of the motor. I have tried both 6Step and FOC, and in both modes the motor fails to startup, but operates normally once I give it a "nudge". At least for my application, it seems like an open-loop startup is still required. Is there any way to accommodate this, or do I have a misunderstanding of the implementation in some regard.

[STuser2]

In sensored mode (Hall / Encoder) there will not be any option for startup configuration. In general motor detects the rotor position based on the hall feedback, and it will start on its own, no open loop startup required according to me. Verify the Hall placement angle which is very critical for proper start up.   

[JandreFrey]

Hi, thank you for the response.

From the motor datasheet, these are the properties:

And then my settings in MCSDK are as follows:
Sensor displacement: 120 degree

Placement electrical angle: 60 degree

Would you say this seems correct?

[STuser2]

To measure the placement angle is documented in the MCSDK, my suggestion would be to confirm either manually or through Motor Pilot.

[VictorChiou]

>>  but operates normally once I give it a "nudge"

it seems like the same issue to this report
https://community.st.com/t5/stm32-mcus-motor-control/6-step-commutation-with-hall-effect-sensors-not-updating-pwm-in/td-p/840662

he says "So if initial duty cycle is low, the motor never starts unless it is manually moved."

[Muthanna]

You've configured how the Hall effect sensors are spaced, which seems to be done correctly.
But you also have to ensure that the phase A/U ('s) peak aligns with the HALL A/U's rising edge by setting the Hall effect sensors displacement parameter. 
This will configure the system to match the phases with the position feedback.
This configuration is available in the MC Workbench as well as in pmsm_motor_parameters.h as HALL_PHASE_SHIFT

If you still see the same issue, try tuning the PI Current Controller.
Refine it even otherwise.
All the best

[Fabrice LOUBEYRE]

Hi @JandreFrey, some corrections regarding Hall sensor management for the 6-step algorithm will be included in the next release of the MCSDK. However, the updated files are attached. Update the project with these files and check the low-speed start performance.

Best regards.

Fabrice

[JandreFrey]

Hi Muthanna,

I’ve spun the motor manually and observed the back-emf and encoder values for hall A/motor U (since the motor profiler tool is not working as of yet). Unfortunately, I couldn’t get a super clear measurement since the motor inductance is very small. From my understanding the encoder electrical angle is 0. 
Nonetheless, after applying these changes, startup is still failing.