BLDC motor stalls when using only hall sensors

4 years 9 months ago - 4 years 9 months ago #29531475 by tbieler
Hi, I have a very simple configuration using hall sensors, no encoder and an analog pot to generate the speed set point. For this test, there is no current problem (working at 10 amps), no voltage problem (30V).
When a set a speed, the motor starts and suddenly stalls generating a high breaking current in the phase.
The hall sequence is OK, the motor always starts and runs the same way in both direction.
The applied PWM is suddenly modified (no synchro with a hall sensor, the speed set point is not modified) causing the motor current being regenerative, until stopped. There's no fault when viewing the drive state. Then the pot has to be back to a 0 speed set point before restarting.
On the attached graphs, Trace 1,2 & 3 are hall sensors input 1,2 & 3. Trace 4 is current of phase 1.
A read another topics where the motor drive was running correctly when an encoder has been connected, but I don't understand why it doesn't work properly using hall sensors.
Latest firmware has been updated.
Thanks for feed-back
Thierry
Attachments:

Please Log in or Create an account to join the conversation.

4 years 9 months ago #29531477 by niko
Hello,

Please give some more details. Are you in open loop? How much time passes after startup and the motor stalls? Can you move the rotor by hand and see the hall counter counting?

Please Log in or Create an account to join the conversation.

4 years 9 months ago #29531478 by tbieler
Hi,

I'm in closed loop, it happens when the speed increases. I can run the motor for an infinite time at lower speed.
The problem also appears in torque mode.
I can see the hall counter counting.

Please Log in or Create an account to join the conversation.

4 years 9 months ago #29531488 by niko
Hello,

it does not look like a regular problem.
What PID values do you use? Which closed loop mode do you use?

Please Log in or Create an account to join the conversation.

4 years 9 months ago #29531491 by tbieler
Please find attached the entire configuration
Attachments:

Please Log in or Create an account to join the conversation.

4 years 9 months ago #29531492 by niko
I would suggest for closed loop speed to use pid = 0,1,0. It works well in almost all setups. See if the problem is fixed. Same pid for torque as well.

Please Log in or Create an account to join the conversation.

4 years 9 months ago #29531493 by tbieler
I'll try tomorrow. Just one question: looking at your hall sensor sequence, '1' on the graph means "high level" thanks to the pull-up or hall activated -> low level?
To get the "high level" as it is on your graph, I had to add some logic inverter, I didn't fount any hall configuration to invert the signals.

Please Log in or Create an account to join the conversation.

Moderators: tonysantoni
Time to create page: 2.439 seconds