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How to calculate calibration angle in PMSM3_1

Hrishikesh Mehta
Prodigy 50 points

Other Parts Discussed in Thread: TMS320F2812, HVPMSMMTR, CONTROLSUITE, TMS320F28335, MOTORWARE

Hi All,

I'm working on sensored field oriented control of PMSM (with Encoder + FOC) using TMS320F2812 eZdsp kit and referring to PMSM3_1 application note for the same. I have completed incremental build level 3 - PID Tuning for Id and Iq and also have verified the encoder feedback signals to be correct in build level 4.

Now I am stuck up with the issue to setting a correct value for the parameter qep1.CalibrationAngle in the program.

I am using the following text as a reference as given in document PMSM3_1 pg. 27-28. (sprc129)

I followed the given instructions. Whenever I set LockRotorFlag to 1, motor stops spinning and get locked but each time I get a different value in EvaRegs.T2CNT with random repeatability of a couple of  values.

Please let me know how do I set a correct value for the parameter 'Calibration Angle' and how to verify if the value is correct.

--

Hrishikesh Mehta

  • 0
    Guru 192875 points

    Hi,

    You will probably need to add the following lines before the QEP_MACRO is called in the interrupt:

     if (lsw==0) 
 {
   EQep1Regs.QPOSCNT=0; 
   EQep1Regs.QCLR.bit.IEL = 1;
 } // Reset position cnt.

if ((EQep1Regs.QFLG.bit.IEL==1) && Init_IFlag==0) // Check the index occurrence  
{
   qep1.CalibratedAngle= EQep1Regs.QPOSILAT; 
    Init_IFlag++;
 } // Keep the latched pos. at the first index

    Refer the HV Kit code more detailed implementation.

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Prodigy 50 points

    Thanks for the reply Gautam. The TMS320F2812 DSP doesnt use the eQEP module. So this piece of code cannot be used directly there. Only if I get a correct value for qep1.CalibrationAngle my problem would be solved.

  • 0 in reply to Hrishikesh Mehta
    Guru 192875 points

    Ohh! F2812 has event manager :)

    Sorry Hrishi, I'll have to go through the datasheet for this. Myself, being a bit busy would request you to be patient. By tomorrow you should receive an expert's opinion.

    Regards,

    Gautam

  • 0
    TI__Guru** 119680 points

    there are many 0 electrical angles per a given mechanical rotation, depending on poles.

    Every time you do a LockRotor you are injecting Id current to align the rotor to the closest 0 electrical angle. So it should be repeatable to the number of pole pairs you have.

  • 0 in reply to ChrisClearman
    Prodigy 50 points

    Yes Chris.. You are right but each time when I set the LockRotor flag to 1, I get a different value.. I tried the values which have high repeatability and used it in build level 5 but motor wont spin with those values.. So I if you can guide me with the procedure of verifying a correct value for Calibration Angle, then that would be useful..

  • 0 in reply to Hrishikesh Mehta
    TI__Guru** 119680 points

    Hrishi,

    I think we have reached the limit of the support we can provide on F2812 (15 yrs since we announced) and this application software (last update 2005, first created in ~2003).  I would recommend upgrading to more recent HW & SW.

    TMDSHVMTRPFCKIT + HVPMSMMTR

    and controlSUITE

    will allow you experiment with TMS320F28335 and Encoder based or sensorless projects.

    You could also take this same HW set-up and purchase TMDSCNCD28069M and experiment with www.ti.com/instaspin-motion , supported through MotorWare (instead of controlSUITE) which is an incredibly effective servo position control with motion solution.  It's the premium solution that we have available.

     

  • 0 in reply to ChrisClearman
    Prodigy 50 points

    Thanks for the suggestion Chris. I have been using TMS320F2812 for the last 1.5 years and suddenly shifting the platform wont be that feasible immediately for me. It can surely happen over a time period. Can this issue be solved in any way by not shifting the platform I am currently working on?..

  • 0 in reply to Hrishikesh Mehta
    TI__Guru** 119680 points

    we don't have a way to support you on this 9+ yr old software. We don't have any of the HW here and no one has used this software. 

    Doing a LockRotor (Id), reading the count, and using that as your offset is the standard way to do things.  We still use the same process in our InstaSPIN-MOTION with Position control.