Sensorless BLDC control using sbRIO

[Gabs01]

Hello!

Is there any example of a sensorless/sensored BLDC low level control using sbRIO FPGA? I am using comparators to sense the back-emf but I am confused as to how should I filter the input, the analog readings of the comparators take 25-26 us and filtering several values would slow down the process too much.

Also I attach an example with what I have until now (sensorless), if anyone has any better suggestions. I use a manual activation of the digital output as pwm signal as the square signal generator seems to slow down my loop and the 1mhz duty cycle looks triangular on oscilloscope, following this example: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000015CPCSA2&l=ro-RO . But for some reason depending on the duty cycle and cycle(commutation) duration, my bldc vibrates and often gets stuck during acceleration.

[ZYOng]

May be Field-Oriented Controller (FOC) / Space-Vector Controller for a Brushless DC Motor Using LabVIEW - N...

[Gabs01]

Hello,

Yes I am aware of this example but unfortunately this is for a sensored bldc motor. I was looking for the low level commutation of a sensorless motor, using backemf and the acceleration phase for an sbRIO fpga. Maybe it can be adjusted but to be honest I don't have enough experience to  do it and was wondering if someone has any advice or direction/example.

[AndersSekanina]

Hi

For the analog input, I would suggest to look at:

https://www.ni.com/docs/en-US/bundle/c-series-reference-and-procedures/page/criodevicehelp/conversio...

In that way you can control the timing better and synchronize the analog input with the PWM.

I will also suggest to use a dedicated single cycle timed loop for PWM generation, in that way you have 100% control of the timing.

Regards Anders