Mechatronics > Motor Control

Quad triphase driver using 8-10 pins

(1/1)

Lego:

Before going ahead with my driver project and wasting a lot of time (and money in parts) I wanted to have some "comfort" from someone with more experience with drivers than I have (which trully isn't much).

My plan Is to use a DAC (a paralel one, most likely just a few pins to control a r2r ladder ) and an analog MUX which uses four outputs to control each of the motors: three thru a pair of inverting and non-invering op-amps that drive a mosfet triphase bridge, another output is used to feed the op-amp that feeds +Vs to the op-apms that control the phases...




At that point I'm playing on my side, controlling the motors at this point is just a programming exercise...

I need either have "sine to r2r-ladder", and "power" tables to feed the DAC and use a timer for the sampling speed of each motor's phases (individual sampling period).
Or find an update frequency that allows me to use different sine tables for different frequencies, or a single table that can be read for more frequencies, there's a lot of choices that should work.

At that point I can give the user two registers (variables) for each motor
 - MxSPEED to control the speed, when changed adapts the sampling timer value to the new speed.
 - MxPOWER that sets the max voltage for the phases

Anything that would help me understand how to choose the right components will be most appreciated (I'm happy with R-This and That-FM).

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