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Power consumption of DRV8312-96EVM board

Amanuel Assefa
Prodigy 45 points

Other Parts Discussed in Thread: MOTORWARE

Hello ,

I am using the DRV8312-69EVM board with the BLDC motor that came with the kit. Is there a way I could get the current and voltage readings of the motor and calculate the power consumed? I wanted to know if I could get these values (current and voltage to motor) from the code. 

Thanks

  • 0
    Prodigy 45 points

    Sorry I posted to quick. The Code I am Referring to is the motorware software distribution and the available labs within it. 

  • 0 in reply to Amanuel Assefa
    TI__Guru** 119680 points

    In proj_lab10 you will find gMotorVars.Is_A variable. This is the total current through the motor.

    Voltage is available as gMotorVars.VdcBus_kV

  • 0 in reply to ChrisClearman
    Prodigy 45 points

    Hello Chris,

    Thanks for your quick reply. I have looked at lab 10 and found the variable you mentioned. I wanted to measure the power consumption while I was running lab 5d so I did the following modification to the updateGlobalVariables_motor(…) method in lab 5d:

    // Get the DC buss voltage

      gMotorVars.VdcBus_kV = _IQmpy(gAdcData.dcBus,_IQ(USER_IQ_FULL_SCALE_VOLTAGE_V/1000.0));

     

      // read Id and Iq vectors in amps

       _iq Id_A = _IQmpy(CTRL_getId_in_pu(ctrlHandle), _IQ(USER_IQ_FULL_SCALE_CURRENT_A));

       _iq Iq_A = _IQmpy(CTRL_getIq_in_pu(ctrlHandle), _IQ(USER_IQ_FULL_SCALE_CURRENT_A));

     

      // calculate vector Is in amps

       Is_A = _IQsqrt(_IQmpy(Id_A, Id_A) + _IQmpy(Iq_A, Iq_A));

     

      powerConsumed = _IQmpy(gMotorVars.VdcBus_kV, Is_A);

     

    when I run lab 5d after the modification, I am able to see the power consumed in the CCS debugger window ( I have it globally declared for testing). I get the following value

    (Please see the attached file) .7115.current_voltage_power_CCS_Read.pdf

     The motor is running at 1KPRM with no load attached.  I am assuming that the current is in Amps and voltage (as stated) is in KV. So my power should be 0.09956 * 23.9308 = 2.38255 Watts( with rounding errors). Does this look right to you? I have a feeling I missed something.

    Thanks.

    In another note, lab 10 doesn’t have any steps in the Instaspin_lProjectsabs guide. It just mentions the lab and there are no steps shown how to execute it. Is there an update to the document? I am using the one provided in motorware

  • 0 in reply to Amanuel Assefa
    TI__Guru** 119680 points

    your powerConsumed should be powerConsumed_kW as you are using kV * Amps.

    It looks correct: 0.0024 kW = 2.4 kW

    Amanuel Assefa said:
    In another note, lab 10 doesn’t have any steps in the Instaspin_lProjectsabs guide.

    Yes, these have been blank since we launched in Feb '13....we REALLY expect to actually update this in the next release in Oct/Nov.  But both 9 and 10 are very straightforward.  You can view video training module Part 5 where I demonstrate them using the Launchpad + Booster kit

    http://www.ti.com/ww/en/mcu/instaspin/support_community.shtml

  • 0 in reply to ChrisClearman
    Prodigy 45 points

    Thank you for the feedback and the link Chris.