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C2000WARE-MOTORCONTROL-SDK: TMS320F280049C

SHIVA SHANKAR
Prodigy 50 points
Part Number: C2000WARE-MOTORCONTROL-SDK

Hi Yanming Luo, Good evening!

Hope you are doing good!

I have few queries  regarding the duty cycle generation 

we have this  structure defined in SDK      HAL_PWMData_t pwmData = {{0.0,0.0, 0.0}};

0.0 = 50% duty cycle

0.45 = 95% duty cycle

and we have V_m  = Vdc / 2 * ( 2 * D - 1)   ,  Where VDC   = Inverter voltage, D = Duty cycle

for 50% duty cycle V_ m  = 0V

Whether duty cycle can be from 0 to 50% ??

for 0% to 50% V_m can be upto -VDC/2 and form 50% to 100% V_m can be upto +VDC/2  ?

Whether above statement is correct ??

Please give me feedback on this.

Thank you

shiva

  • 0
    TI__Guru** 110290 points

    The equations depend on what PWM and inverter type you are using?  In most cases, 2-level inverter is used for the 3-phase motor control, so the three phase with 50% duty means there is no current on motor. So, the statement and equations you mentioned above are correct.

  • 0 in reply to Yanming Luo
    Prodigy 50 points

    Hi Yanming Luo

    Below are few problem that i am facing during testing.

    PI_setMinMax(piHandle_Id, -userParams.maxVsMag_V), userParams.maxVsMag_V);

    float32_t Error;
    float32_t Kp = PI_getKp(handle);
    float32_t Ki = PI_getKi(handle);
    float32_t Up;
    float32_t Ui = PI_getUi(handle);      Ui is getting to saturation an getting to 0.5*Vdc   
    float32_t outMax = PI_getOutMax(handle);
    float32_t outMin = PI_getOutMin(handle);

    Error = refValue - fbackValue;

    //
    // Compute the proportional output
    //
    Up = Kp * Error;

    The Ui Output from pi_id loop goes to saturation at the start of the system. My DC voltage is 40V, so Id saturation is +/- 20V.

    we have Sqrt(Vs^2 - Vd^2)   =  Vq

    Since Ui of pi_id is going to saturation to +/- 20V  , Vq saturation is setting to zero since we have  Sqrt(Vs^2 - Vd^2)   =  Vq

    What can be potential issue that the pi_id is getting saturated 

    Can you suggest us to resolve this issue 

    Thank you

    shiva

  • 0 in reply to SHIVA SHANKAR
    TI__Guru** 110290 points

    Are you using your designed board? Or a TI EVM board? The issue should be from the current sensing or the motor electrical parameters. Please make sure that the current and voltage feedback signals are good for motor control, and also calibrate correctly the offset of current sampling circuit.

  • 0 in reply to Yanming Luo
    TI__Guru** 110290 points

    It's been a week since we heard from you,  so I am assuming you no longer need clarification for your question that will be marking this thread as closed. You can reply with a post or create a new thread if you have any further question on this topic. Thanks.