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TMS320C28346: Using the DMC Library to Implement Field Oriented Control of Stepper Motors

Part Number: TMS320C28346
Other Parts Discussed in Thread: CONTROLSUITE, DRV8412

The examples included in the ControlSuite software tool for Field Oriented Control (FOC) all focus on 3-Phase BLDC or PMSM motors.  In recent years, there has been some focus on better drive performance of Stepper Motors by using FOC (see attachments for more information) as opposed to microstepping.  I am looking for examples of implementation of the DMC Library to drive a 2-Phase Hybrid Stepper Motor using FOC.  I have read through the TMS320C2000 Motor Control Primer Wiki and did find some reference to a potential project in the ControlSuite software that would focus on Stepper Motors.  However, I'm not sure this project was ever created.  

To be clear, because I think some people confuse the two, I am not trying to implement a microstep solution.  Instead, I would like to implement a closed loop control system with three PI loops, current, velocity, and position.  The current feedback will most likely be low side current sensing of the two phases.  The position feedback will not be sensored as I will have a stepper motor with an integrated position encoder.  The application requires very smooth motion at slow speeds.  Stall and step-skips are unacceptable.  This is why I am choosing to use a vector control system over an open-loop microstep system.  

To conclude, I am requesting any information on existing software and/or hardware examples of this type of motor control implementation.  If this does not exist, it would be great to discuss with someone how the current DMC library might be edited to allow a 2-phase drive architecture so that it will work for steppers.

Thank you,

Casey Shea

Microprocessor Designs

Shelburne, VT 05482

wp_040_jat_vergge.pdf

A-Novel-Vector-Control-Strategy-For-Bipolar-Stepper-Motor.pdf.

  • You are right. There are many topics about using SPWM or SVPWM for microstep control of stepper motor. You can find a reference design about the stepper in TI controlSUITE (\ti\controlSUITE\development_kits\DRV8412-C2-KIT_v131).
  • Thank you, Yanming.  After reading your reply, I did look into the DRV8412 example source code and the documentation describing the control mechanisms.  However, it does not appear that this is actually using Vector Control.  There is a closed loop system set up for current but the PI loop only uses current from a single phase as its input.  I do not see any park transformations being used to convert the two phase current components into a rotating reference frame.  Without this, I don't see how it could be performing vector control.

    Are there any examples using vector control for Stepper Motors?  The diagram attached is a good graphical representation of what I am looking for.

  • There are not such FOC example as you shown for stepper motor control now, which is based on sensored. Myabe you can design yourself algorithm refer to other sensored PMSM FOC example in TI controlSUITE.