Looking back to my (few) posts in e14 community, I realized that I've spent more or less 4 years playing with motors. This has been a love-hate relationship for me, and I really can't count how many component I've smoked since then!
About a couple of years ago I decided to challenge myself to build from scratch a brushless motor controller (ESC), without using any pre made scheme or firmware library. This decision escalated and quickly joined with my RC car passion, so the final goal rapidly become building an 1/8 scale capable ESC.
Design constrains that I imposed myself made for a difficult, but very rewarding, journey and I'm really pleased with all the stuff that I've learned along the way. The amount of experience I've gatered is something that I really could not even imagine at the beginning.
CAD image of my ESC
What is special about this ESC, compared to commercial ones?
- Well, it's my own of course!
- Thermal design is as simmetric as possible between high bridge side and low bridge side. I've found only one other commercial ESC that uses a similar thermal design
- Even if my design is sensorless, due to embedded current sensors it can measure rotor position when motor is not rotating, and start the rotation accordingly
- Acceleration profile can be set using current limitation, for a smoother torque control. This is quite helpful with slippery terrains, when a correct acceleration set up helps prevent any slide during acceleration
- It has a soft start mechanism that prevent sparks when connecting the battery
Is it perfect? Of course not! Probably it has more issues than features but it can run for 10 consecutive minutes (that's the duration of a race final) without (usually) giving me problems, thermal design works well even without any fan and efficiency seems to be at least on par compared to commercial ESC's. To me, that's an huge success.
The only thing that remains is to bring it to a local race and see if it can perform well. In the mean time, I will enjoy and continue test it on the road in front of my house.
Some photos of the prototype
Car test, standing start
