Phase/angle calculation

Erik Friesen

Any pointers on calculating angle here? I am toying with a brushless rc motor and inductance angle sensing, not sure about where to start in with the math. I have three adc points taken at the peak amps period. I am giving each phase a short pulse, and measuring the amps.

Leon

This might help:

http://www.microchip.com/wwwcategory/TaxonomySearch.aspx?show=Application%20Notes&ShowField=no

Search on Application > Motor Control > Brushless DC Motors

This is a good one to start with:

http://ww1.microchip.com/downloads/en/AppNotes/00857a.pdf

Erik Friesen

Thanks Leon. Actually the ones I have been using are the an1160 and an1083. 1160 doesn't have a real good start up algorithm, thus I thought I'd give inductive angle sensing a try. It seems to me after a wasted day on the effort that there is too much variance in inductance and componenets to accurately do it. It could be done fairly accurately to 180 degrees, but the nature of it is that there is not enough difference between inductance shown plus and minus with the n and s poles to figure out positively which 180 degree pole it is on.(electrical revolution)