TMS320F28035: Current Limit Algorithm

Hi Yavuz,

Could you check this Q&A on MathWorks forum and see if it is helpful? Thanks!

https://www.mathworks.com/matlabcentral/answers/2129026-dc-current-limitation-in-foc-of-pmsm

Thanks,

Jiaxin

/*--------------------------DC Current Limit Code Snippet depend on SpeedRPM--------------------------*/
    if (DC_Bara_Current_value_mA > DC_BARA_Current_max_limit)
    {
        if (limitHizAtamaSwitch == 0)
            limitedSpeedRPM = YENI_REF_HIZ_FROM_RS422; // speed command assign to limitedRPM value when dc calculated value surpass the limit current value

        limitHizAtamaSwitch = 1;    //for once assign
        akimHizLimitleyici = 1;  // for doesnt assign new command speed value in control algorithm
        limitedSpeedRPM -= 0.1;             // decreasing 0.1RPM every loop
        SpeedRef = _IQ(limitedSpeedRPM / speed1.BaseRpm); // for new proccessing value for speed
    }
    else if (DC_BARA_Current_max_limit - DC_Bara_Current_value_mA < 150.0)   //schmitt zone for 150ma
    {
        if (limitedSpeedRPM > YENI_REF_HIZ_FROM_RS422)
            akimHizLimitleyici = 0; // In hysteresis zone if new RPM value is low from limited RPM valu, it run 
        else
            akimHizLimitleyici = 1; // In hysteresis zone if new RPM value is high from limited RPM valu, it doesnt run 
    }
    else        // normal proccesing 
    {
        limitHizAtamaSwitch = 0; //for new RPM value assign 
        akimHizLimitleyici = 0;
    }
/*-----------------------------------------------------------------------------------------------------------*/

Here my code for current limit depends on speed RPM.

I try to limit DC bara current with speed control of command value but my oppinion there can be another way with control id iq max min parameters. I already calculate DC bara with shunt resistor. If I find out how Id Iq values gives us how much current(their values come with per unit ), I can control them. And also they change through wiht DC bara voltage I know.