2024-04-12 03:59 AM
Hi
I am struggling with the appearance of my BEMF in my 6 step control.
The picture shows one of the phases. And according to all the documentation I've seen ( and I have read a lot ) my BEMF goes the wrong way. The BEMF looks like outstanding ears but it should look like hanging dog ears ( hope that made sense).
I hardware is homemade running a STM32G474.
The PWM is unipolar i.e the lower mosfet is on, during the step, and the PWM is done with the upper mosfet.
At this stage I am bit-banging ( very temporary of course) the PWM so that I have 100% control of the ON/OFF-state of all 6 mosfets.
I think my plan is to detect BEMF during upper mosfet On-time compared with virtual GND.
Any thoughts why my BEMF goes the wrong way is appreciated.