MCSPTE1AK116 - Stall check error occurred while using sensorless bldc motor

[satiz24]

Hi, Am using the mcspteak116 kit with in built bldc sensored motor - its works fine. But when i use the sensoless motor, after running through the FreeMaster the motor starts and spins, after some rotation its stopped, Stall fault occurred. Any insights or how i can avoid that error. Any parameters i need to change.

Is there any updates?

Thanks.

[RadekS]

Hello Satiz24,

If I understood correctly, you used a different BLDC motor. Correct? Did you change also the motor parameters?
if you know the motor parameters, you may enter them in MCAT, store the configuration, and generate the static header file.
If you need measure it, you may use one of our older application notes that may guide you https://www.nxp.com/webapp/Download?colCode=AN4680

In sensored mode, the stall detection is caused by missing pulses from hall sensors.
In sensorless mode, such a option missing and stall possition might be detected only from measured voltages and currents.

Another hint: In the sensorless configuration, the motor starts in open-loop mode because the backEMF voltage is too low for low values of rpms.
It seems that this somehow works on your side. There are necessary some minimum speed for switching into closed-loop (that we are able to correctly detect backEMF voltage). It is possible that your motor is not able to reach such speed in defined time. Please look at Sensorless tab in MCAT and try to increase e.g. the Cmt count parameter... 

BR

RadekS
  

[satiz24]

Hi Radeks,

Yes am using different sensorless bldc motor. The motor startup is working fine, it reaching the 800RPM also. If i let it run for >= 800 RPM continuously it runs fine, But, after some time it stopped and  shows stall error. Sometimes, after startup immediately it stopped, sometimes continuously running for less than a minute and stall error occurred then stopped. I believe the cmt count parameter is for open loop startup. its fine for initial startup and spinning.  I saw the width variation in the back-emf waveforms. So am thinking that this waveform width variation is causing the stall error? I attached the back-EMF waveforms. 

Thanks,

Sathish.

[RadekS]

Hello Satiz24,

thank you for sharing additional details.
Now I understand that the described issue is rather related to a closed loop instead open loop.
From waveforms is clear that there is some issue and most probably the sw does not capture zero cross point correctly. I can see some deviation already on the second "pulse" on the first waveform (E.g. the yellow ON part is too long). Maybe the issue happened soemewhere early.

Hard to say, what could be the reason.
Could you please share the technical spefication of the used motor and the parameters that you used (e.g. screeshot from MCAT or optionally BLDC_appconfig.h)? 

Idea: Maybe you may check the blanking time Toff (During this period, the BEMF voltage is not sensed or used for sensorless control - it filter the transient effects) and compare it with the waveforms.

BR

RadekS

[satiz24]

Hi Radeks,

I appreciate your analysis and update. It's 12V, 2 pole pair water pump motor, Max 4000-6000 RPM will run. Exactly I don't know the current and other parameters of the motor. Is there anything we can avoid these error for continuously run and vary the speed in the software?

[PetrS]

Hi,

Sensorless or HALL sensor mode is selected using HALL_SENSOR macro. This macro is located in motor_structure.h.
Do you have it properly set, rebuilt code and download it again to the MCU, then open FreeMASTER?

BR, Petr

[satiz24]

Hi Petr,

Yes i updated the HALL_SENSOR macro as sensorless. Compiled and downloaded, its spinning initially after some rotations, it stopped and shows stall error in FreeMaster.

[satiz24]

Hi NXP Team, Is there any updates regarding the stall issue?