Charles was kind enough to volunteer his daily mode of transportation for motor controller testing:
|Read: The previous controller melted, or something.|
|FreeFly David's custom e-bike motor.|
|It looks much more legit with a 3d-printed case.|
The next step for FFv1.1 ground firmware testing will be upgrading to nicer FETs and improving heat sinking a bit. One FET option is the proven 75V IRFS3107-7, used on Cap Kart's half-bridge and the Victor 883107-7 controller. These have already shown that they can handle 75A acceleration current with no trouble. An even lower resistance option would be the 60V IPB017N06N3 G. It also has half the gate charge of the 3107-7, so it will cut down on the switching losses. I'm not sure I would use it with a 12S LiPo (44.4V nominal, 50.4V fully charged) system, but the current 60V FETs have proven sufficient for 12S A123 (39.6V nominal, 43.2V fully charged).
On to smaller things...
FFv1.1 (and v1.0, really, since it was virtually the same) have been very successful so far. The DRV8301 magic chip has proven its worth, since I have yet to see any noise problems at all. The target application for FFv1.0 and v1.1 was large multirotor motors, specifically for the CineStar 6, and I designed them with 20-30A continuous motor phase currents in mind. With good heat sinking or air cooling, they can probably handle 50A continuous phase current. But now I realize that it might be useful to have a smaller, lighter version for things in the 10-15A continuous phase current range. So it's time for a new revision, FFv1.2s:
My target application for these is the smaller multirotor motors, such as the ones on my Talon quad. The FFv1.1 boards have already shown significant increase in efficiency on the Talon quad, but they eat up all their advantage by being much heavier than the Turnigy controllers it normally uses (65g from FFv1.1 vs. 19g for the Turnigy Plush 18A). I don't know if I'll get all the way down to 19g, but FFv1.2s should be close to that. Even though the board area is only 33% smaller, the weight should shrink by a lot more with the thin FETs and smaller capacitors.
Because the logic and gate drive section is the same as FFv1.1, it will still be a full-featured sinusoidal FOC setup with wireless capability through the XBee. (For minimum cost/weight configuration, the XBee will be left off, but it's useful to have the header there for wireless programming/debugging.) As usual, I will post the relevant design files pending testing.