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Simultaneous FOC of 3 motors

Taseen Jawad
Prodigy 70 points

Other Parts Discussed in Thread: TMS320F28027, TMS320F28069, TMS320F28075, CONTROLSUITE

Hi,

I have been trying to accomplish the simultaneous control of 3 motors with FOC. So far, I have had success using the TMS320F28027 and TMS320F28069 chipsets with InstaSPIN for 1 and 2 motors respectively. However there seems to be no option to do the same for 3 motors.

The solution I am currently exploring is implementing FOC using the TMS320F28075 chipset. However, it does not contain the FAST estimator necessary to implement FOC. The estimator is part of the ROM of the 28069 and 28027 chipsets. 

This brings me to my questions:

1) Is there any way to implement the FOC on the TMS320F28075? Preferably using the FAST (or similar) estimator? 

2) If not, do you have any recommendations for products/combinations of products that would allow me to implement 3-motor FOC without having to use a separate controller chipset for each motor (timing issues, etc.) as the 3 motor controls are dependent on eachother. For example, is the FAST estimator available on its own for me to use with the TMS320F28075? etc. 

3)If 1) and 2) don't apply, is there any way to get a packaged version of the estimator, I understand that it is proprietary, but is there any way for me to use it on a chipset that it does not come on by default?

All I really would like to do is control 3 motors simultaneously using FOC. All suggestions welcome! 

Thanks!

  • 0
    TI__Guru** 119680 points
    You can't use InstaSPIN-FOC for 3 motors on one chip. The Library is only built for 2 instances. You could try using the eSMO (sensorless) or Encoder FOC from controlSUITE on an F2807x or F2837x.

    No, there is no way to use FAST on other chips, only available in ROM on select devices.
  • 0 in reply to ChrisClearman
    Prodigy 70 points
    Thank you Chris for the prompt reply.

    I have looked at both the eSMO and SMOPOS documentations and have a few questions. From my understanding, FAST and eSMO/SMOPOS serve the same purpose - they are both observers. This leads me to a few questions

    1) What are differences between these modules and FAST in terms of performance? For FAST to be a product on its own, there must be some differences. (i.e. is it faster, more accurate, etc)

    2) When looking at:

    a)SMO modules as the observer

    vs.

    b) Figuring out a solution that allows the use of modules that already contain FAST (e.g. using multiple chipsets, etc) as the observer


    Are there benefits/costs with from a design and performance perspective with using either (a) or (b). Essentially, in terms of performance, are the integrated modules with FAST better? if so, how?

    The main reason I did not want to use multiple MCUs is due to synchronization issues possibly introducing delays into the system. However if the FAST algorithm is that much (haha) faster in implementation, it would overturn that concern.
  • 0 in reply to Taseen Jawad
    TI__Guru** 119680 points
    FAST is superior in every way except that it requires phase voltage sensing and it takes more calculations. It is MUCH easier to get running and tuned because InstaSPIN-FOC features motor ID, the motor parameters required are fewer, and the observer is self tuning, the current controller gains are auto set, and the speed controller gains are chosen to typically at least be stable to start. Getting SMO/eSMO running is much more difficult.

    once running, FAST will work at lower speeds, be stable at higher speeds (especially at ultra high speeds), work through zero speed, the control system will be stable (though not track) at zero speed, handle stall conditions, and will track a moving rotor even with the PWM/inverter turned off (so it can synch to an already moving motor).

    eSMO/SMO may be good enough for your application. IF you can get it running and tuned easily, which is not always the case.

    unless you are very experienced in sensorless control I would have a hard time recommending anything other than FAST / InstaSPIN-FOC.
  • 0 in reply to ChrisClearman
    Prodigy 70 points

    Hi Chris,

    Thanks for the quick reply yet again!

    Would it be possible to license the FAST/instaSPIN APIs or access the source code?

    Thanks!

  • 0 in reply to Taseen Jawad
    TI__Guru** 119680 points
    sorry, no, that's not an option
  • 0 in reply to ChrisClearman
    Prodigy 70 points
    Just to clarify, in case it changes things.

    By license, I am referring to accessing the libraries and using them on another TI chip with the hardware necessary for my purposes.

    Is there any process or option to go about doing that?

    Thanks!
  • 0 in reply to Taseen Jawad
    TI__Guru** 119680 points
    there is no process for that.
    The InstaSPIN-FOC & -MOTION libraries are only available in ROM on select Piccolo devices.