I am working on a project where I need some ESC (electronic speed controllers)s. The project is a quad copter with 4 three-phase brushless motors.
The brains of the thing will be
https://www.olimex.com/Products/SOM/A20/ , the reason for picking this board is for a lot of reasons, but namely I am have a degree with an AI major and would like to play with the algorithms I learned (such as multi-agent systems, neual networks, etc). I also want to learn as much as I can about electronics with this project. So as such I would like to build my own board which will have 4 ESCs as well as sensors (MPU9250, MS5611-01BA03 and Venus838FLPx, all of which use SPI).
I have two options on controlling the speed via the CPU, I can either use a DAC, or PWM. After watching one of the best explanations of what PWM on actually is on YouTube
and considering all of my components will be using SPI. I plan on using a DAC to control speed (and its relatively cheaper than going with a PWM, because I would need 4 microcontrollers to maintain the PWM signal just for the motors). This also makes my circuit considerably simpler and modular as well.
So the next thing I need to do is convert that analog DC to three-phase AC to turn the motors. And this is where I am a bit stuck, the ON SEMICONDUCTOR STK5F1U3E2D-E does what I want (I think anyway), however its $95.
So my question is this, how do I convert DC into three-phase AC, which can support 50A without spending $95?