RE: [CAD_CAM_EDM_DRO] DIY brushless controllers?

If you want to roll your own I would highly recommend using the PMD MC3310
chip which takes care of all the commutation, phasing, communication,
trajectory generation etc (no I don't work for them). We have close to 200
BLDC drives based on the PMD chipset that I designed out in the field and I
have not had a single problem with them to date. If you really want to write
the firmware yourself (a wonderful learning experience ) then consider the
TI or Motorola DSP chips that have been optimized specifically for brushless
DC control; Motorola even throws in some code snippets to get you started.
The OSMC group (check the OSMC yahoo news group) is currently discussing the
amplifier section of the BLDC drives; the FETs current sensing techniques
etc. That would be the group to join if you want to be a part of the open
source design they are pursuing right now.
Madhu

>-----Original Message-----
>From: bluecoast@... [mailto:bluecoast@...]
>Hi again,
>
>Has anybody taken a crack at homebrewed brushless controllers? I
>notice Microchip has two interesting appnotes that could be used for
>this:
>
>Brushless DC motor control made easy (speed-torque control)
>(http://www.microchip.com/1010/suppdoc/appnote/all/an857/index.htm
>
>PIC16XXXX/18XXXX DC Servomotor (brushed position control)
>http://www.microchip.com/1010/suppdoc/appnote/all/an696/index.htm
>
>So a position controller would be basically a combination of these
>two applications... the second addresses optical encoder up/down
>count; the first the pwm sinusoidal generation to drive the actual
>brushless motor.
>
>Has anybody seen or experimented with these?
>
>Microchip also has some other neat app notes about brushed servo
>control, and one cool sinusoidal microstepping drive.
>
>I just wanted to get talking about brushless drives and pitfalls
>with them since there aren't so many options for us as opposed to
>brushed/stepper etc.
>
>Cheers,
>Andrew