24 bit PWM to generate 3 Phase AC Voltage and Current Source

[BasePointer]

Hi to all,

We are producing 3 phase solid state enery meters. For test purpose, we need an accurate, stable three phase voltage and current sources. We want to make our own test machine in the factory. At first we may start with single phase voltage and current generator. Due to we produce solid state energy meters, we can easly measure rms voltage, current, active power, reactive power accurately as feedback. Our problem is generating signals and using measured values as feedback.

Our final goals are:

Voltage Range: 10Vac-550Vac, 0.1V steps (5500 steps, 16 bit PWM is enought)

Current Range: 1mAac-120Aac, 1mA steps (120000 steps, 24 bit PWM is enought)

Phase Angle: 0-360degree, 0.1degree steps (3600 steps, it needs 180Ksample/sec at 50Hz?)

We think of using PWM but 16 bit resolution doesn't seem enough.

What do you advice us for such as application? Where to start? We have no idea about if we need PID loop. May we use 24 bit sound driver(class-d) instead of 16 bit PWM outputs of the MCUs or DSCs?

Which MCU or DSC should be used for this application?

Regards,

BP.

Message Edited by BasePointer on 2008-05-22 08:41 AM

[trytohelp]

Hi,

I think we should forward your request to the MCU team and /or FAE.

This is not the right place for this type of question.

I suggest you to log your request to the Freescale CRM system.
Please use Freescale on line support web page.
  - Go to following URL: http://www.freescale.com/TechSupport
  - Click on Submit a Service Request to create a new one or Manage Existing Service Request.
  - You will come to a login page.
  - You can submit your request through the web from there or view the activities of a SR.

Regards

Pascal

[BasePointer]

Hi,

Actually I did it, but not happy with the result.

So I decided to try here.

10x,

BP.