Unable to spin the motor using Speed Sensing Mode - Hall Sensor

[AkhilDP]

Hello,

We have a 5 pole pair magnet rotor and we have been using STEVAL-CTM009V1 development kit along with NUCLEO-G474RE development board.

First, we did a preliminary testing with a sensorless control (observer+PLL) and after understanding the aspects of the Start-up Profile under Sensorless Startup Parameters in Workbench we got the motor to spin smoothly although the start was a little jerky and the direction of rotation wasn't consistent but took of quite well after 50rpm all the way upto the defined speed.

Second, we now tried to spin the motor with Hall sensor as Speed Sensing Mode and clicked "Start" button under the Control from Motor Pilot. While there was about 0.14A of current drawn from the power supply when we started the control, absolutely no action in the Motor. Waited for a while, before stopping or resetting the operation, and rotated the rotor manually by hand and now Speed Feedback Error showed up. Obvious to note, the motor still didn't spin. Just so you know, we got the Hall angle placement right (mechanically and electrically). Got each of the sensor checked and they are working fine too. They are also connected to appropriate 2,3 & 4 Pins respectively of CON8 on STEVAL-006V1. Also to note, this exact motor was spun using a different controller to validate and verify the unknowns from the Motor side and resolve if any. Motor is fine.

Few observations and settings that remained constant during both of the above 2 operations:

1. A constant whirring sound in the motor as soon as the control was started from the Motor Pilot irrespective of sensored or sensorless control.

2. Open loop was unchecked.

3. Modulation Flags: None.

4. Control Mode: Speed Control

What are we missing? How do we get it running with Hall Sensors? Let me know if you need any info from our end to understand the issue better.

Thanks.

[GMA]

Hello @AkhilDP.,

Could you please send a scope display of the H1/H2/H3 signals on NUCLEO-G474RE running the main=sto-pll - aux=Hall use case when motor is spinning (few cycles and scope channel - Hx signal correspondence)?

And also with main=Hall start-up?

[AkhilDP]

Hello @GMA ,

Sure, Below are the snaps of the oscilloscope for the Hall Feedbacks.

 
Img1: Main: STO-PLL, Aux: Hall. This is while the motor is spinning

 Img2: Main: Hall. (motor isn't spinning, hence no change in the Hall states. H1-1, H2-0, H3-1). Please note that the current is still getting drawn from the power supply as I mentioned about it earlier.

[GMA]

Hello @AkhilDP,

According to the scope, the "Sensors displacement" is 120°, is-it your used setting?

[AkhilDP]

Hello @GMA ,

Yes, Precisely. That's the setting I used.

As I had mentioned earlier we did all the necessary steps as provided in the Launch Workbench 6.1.2 -> About -> Documentations -> User Manual -> Hall sensor feedback processing.

[GMA]

Hello @AkhilDP,

Coming back to your first trial figure, switching motor U and V phase signals I have the same result as you on your first shared plot:

If I understand correctly, HALL sensor signals have been modified to align both electrical angles, but it seems that motor phases were not correctly connected... Could you try setting H1,H2,H3 as on your first trial but using U,V,W phases to align both electrical angle?

[AkhilDP]

Hello @GMA ,

As suggested we set our H1, H2, H3 as per the first trial and interchanged U & V. By doing so the motor spun in opposite direction and both 'STO_EL_Angle' and 'Hall_EL_Angle' followed the same pattern but weren't aligned. The Placement electrical angle had to be changed to get them aligned. But the motor still didn't run in Main:Hall Sensor Mode and behaved as usual drawing some amount of current without spinning.

Also, we tried with various other Hall and Phase combinations, but had not effect on Main:Hall Sensor mode.

There should be some issue with the algorithm and not in the hardware. We have exhausted all options on getting the placement angle of hall and phase but none of them seem to work.

[AkhilDP]

Hello @GMA ,

Any updates on how to resolve this? It's been a while since I heard from you.

Please let us know if you have anything in mind that we could try.