first steps with dsPIC + IRAMS AC servodrive

[andy55]

Been working on an AC servodrive using a microchip dsPIC microcontroller and an IRF IRAMS powerstage.

Got the motor spinning for the first time, see pics below (an entry to 'worlds ugliest servodrive' contest perhaps ? )

this is basically a realization of microchips application note AN1017
http://ww1.microchip.com/downloads/e...tes/01017A.pdf

when the code is tidy enough to release I will post it here or on my website.

When I'm moderately happy with this rough looking prototype I will have to make a nicer board, hopefully everything fits on an 100x160mm eurocard.

btw. anyone know how big a 0.3 - 0.5 C/W heatsink needs to be ? forced air-cooling with a fan ?

AW

[andy55]

I've described the latest progress in my blog at
http://www.anderswallin.net/2006/06/...pic-irf-irams/

[drawbar]

Hey,

No one ever said PROGRESS had to look PRETTY!

Nice going!

Brian

[tivoidethuong]

how about your project?

[andy55]

I have not had time to work with this project. We got some DC servos instead and are fitting them to the cnc mill now.
It would not be terribly hard to make a working AC servodrive from these components. So if anyone is interested do get in contact and I can help with the little experience I got...

[tivoidethuong]

thanks andy, i'll PM to you

[fr0st]

What control algorithm are you using? PID or a cascaded velocity and position loop?

IIRC a larger sized computer processor cooler should be around 0.5-0.6 C/W

[andy55]

if used with EMC, these AC servo drives would only need to take care of the three-phase sinusoidal commutation.
EMC would send a pwm/analog torque command, and the drive would set either the voltage(simple) or the winding current(a bit more involved) to a value corresponding to the pwm command.
EMC would then have knowledge of the encoder position and would run the position PID loop.

that was my original idea anyway - but as I wrote above I am not working on this anymore.

granitedevices recently have come out with a drive that also has the speed and position loops (so you can control it with step/dir signals). http://granitedevices.fi/