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PMSM sensorless control design using a Piccolo TMS320F28035

Bjornsn
Prodigy 20 points

Other Parts Discussed in Thread: TMS320F28035

Hi Folks,

I decided to use the new Piccolo TMS320F28035 DSC for designing a motor control platform and I ordered the experimenter's kit. I have a couple of question where I need some help:

1. Are there schematics to use in EAGLE that show me an example of how to connect the pins of the uC with peripherals (current sensing and ADC voltage levelling) and how to set up "housekeeping" circuitry (i.e. voltage supply)?

2. I learned in a different thread that there is the VisSim Embedded Controls Developper Suite. Does that software support the TMS320F28035 DSC hardware? I thought maybe it is possible to use parts of the auto-generated code and port it to the 28035 (I know the EDC supports 28027).

3. Even without using the CLA, is the 28035 capable of doing sensorless FOC at 30 kHz sample rate? If not, how about 20 kHz :-) ?

4. Will there be example projects that show the utilization and programming of the CLA?

5. Can I fire the ADC three times per PWM period by a programmable, but barying delay for single current shunt sensing (in order to eliminate phase current measurements?) ?

Thanks so much for your help!

-BJ

 

  • 0
    TI__Guru 57255 points

    BJornsn,

    1. Are there schematics to use in EAGLE that show me an example of how to connect the pins of the uC with peripherals (current sensing and ADC voltage levelling) and how to set up "housekeeping" circuitry (i.e. voltage supply)?

    -Each C2000 kit comes with schematics, BOM files, etc and these are included with each kit's hardware developer's package (found within C:/TI_F28xxx_SysHW/ when the kit software is installed).  Your kit, the F28035 Experimenter's Kit will come with a F28035 controlCARD; this controlCARD's schematics will give a good idea on how to set up the "housekeeping" circuitry.  All installers and such can be found at http://www.ti.com/f28xkits.  For these kits, we use ExpressPCB (http://www.expresspcb.com/), a free schematic and PCB editing tool.

    2. I learned in a different thread that there is the VisSim Embedded Controls Developper Suite. Does that software support the TMS320F28035 DSC hardware? I thought maybe it is possible to use parts of the auto-generated code and port it to the 28035 (I know the EDC supports 28027).

    -I am unsure, perhaps someone else here can answer.

    3. Even without using the CLA, is the F28035 capable of doing sensorless FOC at 30 kHz sample rate? If not, how about 20 kHz :-) ?

    -I did preliminary work on the F28035 which turned two motors with FOC.  Without cleanup, each motor was set at 10KHz switching frequency and was using about 60% utilization. Having one motor spin with 20KHz (and 30KHz with some optimization) should not be an issue.

    4. Will there be example projects that show the utilization and programming of the CLA?

    -Over time these projects will begin to come in. At this point the F2803x header file set includes a simple CLA initialization and ISR run example (http://focus.ti.com/docs/toolsw/folders/print/sprc892.html) When the part reaches its TMS date(the date that that full characterization data and documenation is completed) we expect to have many more projects that work with the CLA.

    5. Can I fire the ADC three times per PWM period by a programmable, but barying delay for single current shunt sensing (in order to eliminate phase current measurements?) ?

    -the answer for how to implement your question is dependent on how you configure your PWMs
    -for most of our previous motor control projects (http://focus.ti.com/mcu/docs/mcuorphan.tsp?contentId=51397) we use up-down PWM mode with all three phases being synchronized.  Because of this, when the PWM timers reach zero (the zero event), switching losses will be minimal.  At this PWM event (say when PWM1A reaches zero on the PWM timer) we trigger the ADC to sample each leg current.
    -on C2000 devices, and especially on Piccolo, ADC sampling is very flexible. To vary delay you will need to create different PWM event triggers to trigger ADC conversions.

  • 0 in reply to Brett Larimore
    Prodigy 20 points

    Thanks for your quick answer, Brett!

    It's too bad that I cannot use the schematic as PCBExpress uses a proprietary data format that I cannot import to EAGLE. I will have to look at it and redo all the devices and connections in EAGLE.

     

    Cheers,

    BJ

  • 0 in reply to Bjornsn
    TI__Intellectual 1615 points

    Bjornsn,

          We also include the Gerber files. I'm not familiar with Eagle, but perhaps you could use those instead of the Express PCB files.

    Charlie

  • 0
    Intellectual 340 points

    Hi Bjorn,

    As you point out, we do support the F28027, and the F28035 is not far removed from it. The F28035 just has some more RAM and flash + CAN.  We should have the support on-line this week. I'll post a note here when it's ready.

    Pete

  • 0 in reply to pete darnell
    Intellectual 340 points

    Hi Bjorn,

    The latest VisSim/ECD update now supports the F28035. We recently ran a closed position loop on a BLDC motor using Hall sensors for both commutation and positioning and it used about 36% CPU at 100kHz sample rate.

    You can download the latest VisSim/ECD here.

    Regards,

    Pete

  • 0 in reply to pete darnell
    Intellectual 890 points

    Hi Pete,

    Does VisSim make use of the CLA in the F28035?

     

  • 0 in reply to Gerry S
    Intellectual 340 points

    Hi Bluehash,

    No, not yet, but we have a complete working diagram to program the motor kit here: http://www.vissim.us/solutions/field_oriented_motor_control.html

    It explains how the diagram was developed and lets you download both the source diagram and the debug diagram. You can control motor operating mode (off, open loop speed, closed loop sensorless speed control), PWM phase gain, and speed command interactively from VisSim in the debug diagram as well as look at the sliding mode position estimation and phase currents in a digital scope block. With the control loop clocking at 10 kHz, only 27% of the main CPU is used, so the CLA is not really needed for this app.

    Regards,

    Pete

     

  • 0 in reply to pete darnell
    Intellectual 890 points

    Thanks for the clarification.

  • 0
    Expert 1845 points

    Hi,

    Does anyone know if a F28335 controlCard can be used with the DIMM slot on the experimenter board?

    Thanks,

    Tim

  • 0 in reply to Tim11828
    Genius 5170 points

    I believe it is possible - may be TI folks will clarify.

  • 0 in reply to Tim11828
    TI__Guru 57255 points

    Tim,

    Yes, the DIMM on the Experimenter Kit (and all evaluation kits) is built to accept any controlCARDs. Please take a look at the documentation/schematics found in the Hardware Developer's Package for the F28335.  This package can be found at http://www.ti.com/f28xkits.


    Thank you,
    Brett

  • 0
    Genius 5170 points

    hello BJ

    If possible, I would like to better understand your #2 question (3. Even without using the CLA, is the 28035 capable of doing sensorless FOC at 30 kHz sample rate? If not, how about 20 kHz :-) ?) - 30kHz switching for a motor drive sounds very high, in fact even 20kHz is kind of pushing the limit. Of course switching will depend on the size of the drive. Do you have any suggestion/advice on how to manage high switching losses?

  • 0 in reply to Arefeen
    Intellectual 340 points

    Hi Arefeen,

    As I posted above, we have use our block diagram language VisSim to program the F28035 for sensorless FOC. With the control loop clocking at 10 kHz, only 27% of the 100 microsecond sampling interval is used without using the CLA. So you could go 30kHz if you wanted to. Note that we have a large number of debugging items in the diagram as well (5 scalars in, 5 scalars out, and 2x200 element buffers of phase current waveform data for display on VisSim's digital scopes. You can read more and download a 2 month free VisSim trial plus the F28035 sensorless FOC diagrams here. Note that you will have to sign in to download the trial and the sample FOC diagrams.

  • 0 in reply to pete darnell
    Genius 5170 points

    Hello

    Thanks for the information as well as for the link. I will most likely download the material sometime in January in order to optimize the use of my free trial period [:D]

  • 0 in reply to pete darnell
    Genius 5170 points

    By the way, we will not be able to switch at 30kHz or even at 20kHz to keep out switching losses reasonable. So, your implementation of 10kHz will most likely work fine . Again, thanks for providing the reference.

  • 0 in reply to Arefeen
    TI__Guru** 119680 points

    Regarding the CLA questions, we are creating a CLA FOC library and are porting one axis of the Dual Axis kits to run off the CLA, the other running off of the 28x CPU.

    We plan to release this in the first part of Q1.

    BTW, on the topic of benchmarks, we have taken the standard release of the DMC Library and Systems and are optimizing them using:
    http://focus.ti.com/lit/an/spraak2/spraak2.pdf

    We will be releasing new Piccolo and then Delfino DMC Library / Systems starting mid-January.

    For the Dual Axis Kit these optimizations allow for the following on 60 MHz Piccolo F28035:
    Each FOC Axis @ 10 KHz = ~12 MIPS
    PFC @ 50 KHz = ~15 MIPS