incememed
10 W
EDIT: Links to papers, appnotes or similar dealing with sensorless startup procedure (and especially of heavier loads) would be much appreciated.
Hi,
As many of you have experienced, fiddling with hall effect sensors for motor positioning can sometimes be quite annoying. I was affected to the extent that I decided to explore a sensorless controller alternative instead. Having first hand experience with the volatile nature of the R/C controller, and considering the kind of riding I do - trail riding - such controllers were ruled out. Further, considering the seemingly non-existance of alternative sensorless controllers, I opted to make one from scratch.
One major concern was its ability to maintain sync in critical conditions; for example during sudden load variations (roots, rocks etc) at low rpms, or just plain riding at very high rpms. I'm happy to conclude that initial tests show tentatively positive results in this respect, see vid for details.
[youtube]civcrAzjmsc[/youtube]
(Overcurrent protection is cutting out too easily, hence the careful throttling going uphill).
If things work out as planned, once rotating, I hope to see no difference in performance between the sensorless controller and a sensored one. However, recreating the awesome zero rpm torque of the sensored drive seems very far off.
The controller was implemented using a Microchip dsPIC processor. The power stage consists of six TO-247 size FETs.
Future plans include merging the controller and the power stage into one single circuit board. For the moment however, having the controller as a breadboard implementation facilitates testing new features, rewiring etc. The whole package also needs waterproofing. To be continued.
BR/Mattias Rahm
PS Nice job so far on saving the forum!
My wish for an improved forum: Controller Technology section. And in my dreams: a dedicated dirt/offroad/downhill section.
Hi,
As many of you have experienced, fiddling with hall effect sensors for motor positioning can sometimes be quite annoying. I was affected to the extent that I decided to explore a sensorless controller alternative instead. Having first hand experience with the volatile nature of the R/C controller, and considering the kind of riding I do - trail riding - such controllers were ruled out. Further, considering the seemingly non-existance of alternative sensorless controllers, I opted to make one from scratch.
One major concern was its ability to maintain sync in critical conditions; for example during sudden load variations (roots, rocks etc) at low rpms, or just plain riding at very high rpms. I'm happy to conclude that initial tests show tentatively positive results in this respect, see vid for details.
[youtube]civcrAzjmsc[/youtube]
(Overcurrent protection is cutting out too easily, hence the careful throttling going uphill).
If things work out as planned, once rotating, I hope to see no difference in performance between the sensorless controller and a sensored one. However, recreating the awesome zero rpm torque of the sensored drive seems very far off.
The controller was implemented using a Microchip dsPIC processor. The power stage consists of six TO-247 size FETs.
Future plans include merging the controller and the power stage into one single circuit board. For the moment however, having the controller as a breadboard implementation facilitates testing new features, rewiring etc. The whole package also needs waterproofing. To be continued.
BR/Mattias Rahm
PS Nice job so far on saving the forum!
My wish for an improved forum: Controller Technology section. And in my dreams: a dedicated dirt/offroad/downhill section.