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ESC with FOC and sensor - why not

Posted by Jure M on March 28, 2015 at 1:10pm

So for a while I was thinking of creating a big ass tilt rotor tricopter with a X8 as a base frame. All good, but which ESC to use? After deciding that I don't really like anything on HobbyKing, I started working on my own. It had to have good quality components, rated for automotive applications (don't want my ESC to fail when flying...), FOC control, CAN/RS232/PWM interface and rotor position sensor input.

So after a couple of months, it is spinning. With a "bit" better micro than an 8 bit Atmel and a 12$ sensor chip we can get instant responses from motor to requests from the control - be it for faster/slower speed, startup from standstill or completely reversing rotational direction. And because it is field oriented control, when motor is decelerated it sends power back to the battery.

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Comments

  • Andrew Zaborowski March 29, 2015 at 8:30am

    What's FOC?

    You can probably get most of these things out of SimonK on an AfroESC.  I get direction reversal, 16-bit throttle, voltage, temperature and RPM / magnetic position over I2C with a modified SimonK firmware.

  • Jure M March 29, 2015 at 2:01am

    Some day I might open source the code, but currently it is much too messy and there are a few tweaks I want to make before that :).

    A "bit" better is Freescale's DSP 56f8037, but to be honest it could use a bit more power - it takes a lot of time to process the algorithms and I still want to have sensorless backup in case that the position sensor fails, and that means that I will probably have to switch to something like this: 56f84763. Why Freescale? I am most familiar with them when it comes to motor control, they have good motor control libraries and they have really good real time debugging tools.

  • Gerard Toonstra March 28, 2015 at 7:33pm

    Nice man!  They are certainly a lot more quiet and no high-pitched frequencies inbetween. 

    Can you elaborate what you mean with "bit" better than 8-bit atmel?

    The sensor may be a better choice in the end, because the sensorless implementation is pretty difficult to get right due to the computational complexity, the oscillations and the required calibration of motor parameters. Looking forward to seeing this thing fly and the sound it makes. Keep us updated!

  • Jerry Giant March 28, 2015 at 2:01pm

    great job! would you consider to open source it?

This reply was deleted.