CCS/TMS320F28069M: How to change the PWM deadband falling/rising edge delay count

Jonathan Azevedo1

Part Number: TMS320F28069M
Other Parts Discussed in Thread: DRV8303

Tool/software: Code Composer Studio

Hello,

Thanks in advance for the help with this topic!

In hal.h, we define the below for the deadband. Due to some of the modes we use our motor in, we need to update the deadband on the fly. Is this possible? We are using TMS320F28069M and DRV 8303.

Thanks!
Jonathan

_________________________________________________________________

//hal.h This is where we define the deadband

//! \brief Defines the PWM deadband falling edge delay count (system clocks)

//!

#define HAL_PWM_DBFED_CNT 500 // 8205-725 8208-320

//! \brief Defines the PWM deadband rising edge delay count (system clocks)

//!

#define HAL_PWM_DBRED_CNT 500 // 8205-725 8208-320

______________________________________________________________________

//Main.c Below is a snipped where we are calling PWM functions

if(CTRL_isError(ctrlHandle)) {

// set the enable controller flag to false

CTRL_setFlag_enableCtrl(ctrlHandle,false);

// set the enable system flag to false

gMotorVars.Flag_enableSys = false;

// disable the PWM

HAL_disablePwm(halHandle);

} else {

// update the controller state

bool flag_ctrlStateChanged = CTRL_updateState(ctrlHandle);

// enable or disable the control

CTRL_setFlag_enableCtrl(ctrlHandle, gMotorVars.Flag_Run_Identify);

if(flag_ctrlStateChanged)

{

CTRL_State_e ctrlState = CTRL_getState(ctrlHandle);

if(ctrlState == CTRL_State_OffLine)

{

// enable the PWM

HAL_enablePwm(halHandle);

}

else if(ctrlState == CTRL_State_OnLine)

{

if(gMotorVars.Flag_enableOffsetcalc == true)

{

// update the ADC bias values

HAL_updateAdcBias(halHandle);

}

else

{

// set the current bias

HAL_setBias(halHandle,HAL_SensorType_Current,0,_IQ(I_A_offset));

HAL_setBias(halHandle,HAL_SensorType_Current,1,_IQ(I_B_offset));

HAL_setBias(halHandle,HAL_SensorType_Current,2,_IQ(I_C_offset));

// set the voltage bias

HAL_setBias(halHandle,HAL_SensorType_Voltage,0,_IQ(V_A_offset));

HAL_setBias(halHandle,HAL_SensorType_Voltage,1,_IQ(V_B_offset));

HAL_setBias(halHandle,HAL_SensorType_Voltage,2,_IQ(V_C_offset));

}

// Return the bias value for currents

gMotorVars.I_bias.value[0] = HAL_getBias(halHandle,HAL_SensorType_Current,0);

gMotorVars.I_bias.value[1] = HAL_getBias(halHandle,HAL_SensorType_Current,1);

gMotorVars.I_bias.value[2] = HAL_getBias(halHandle,HAL_SensorType_Current,2);

// Return the bias value for voltages

gMotorVars.V_bias.value[0] = HAL_getBias(halHandle,HAL_SensorType_Voltage,0);

gMotorVars.V_bias.value[1] = HAL_getBias(halHandle,HAL_SensorType_Voltage,1);

gMotorVars.V_bias.value[2] = HAL_getBias(halHandle,HAL_SensorType_Voltage,2);

// enable the PWM

HAL_enablePwm(halHandle);

}

else if(ctrlState == CTRL_State_Idle)

{

// disable the PWM

HAL_disablePwm(halHandle);

gMotorVars.Flag_Run_Identify = false;

}

if((CTRL_getFlag_enableUserMotorParams(ctrlHandle) == true) &&

(ctrlState > CTRL_State_Idle) &&

(gMotorVars.CtrlVersion.minor == 6))

{

// call this function to fix 1p6

USER_softwareUpdate1p6(ctrlHandle);

}

Hello Han,

We are getting back into this project and I have a few questions about implementing the functions you laid out below.

_____________________________________________________________________________________________________

_______________________________________________________________________________________________________

As we are controlling all the PWM functions through hal, will the above functions still work?

_______________________________________________________________________________________________________

________________________________________________________________________________________________________________________

With using the functions, do we still need to define both HAL_PWM_DBFED_CNT and HAL_PWM_DBRED_CNT in hal.h?

__________________________________________________________________________________________________________________________

____________________________________________________________________________________________________________________________

Would this be correct for a 500 microsecond delay? PWM_setDeadBandRisingEdgeDelay(PWM_Handle,500)

Thank you again for all the help!

Best,

Jonathan

over 6 years ago

0 Hareesh Janakiraman over 6 years ago

TI__Guru* 95315 points

Your post has been assigned to an expert. On a different note, if you insert a code snippet in your post, always paste it using the “Syntax Highlighter” option. That makes the code easier to read.

0 Jonathan Azevedo1 over 6 years ago in reply to Hareesh Janakiraman

Intellectual 412 points

Hello,

Thanks in advance for the help with this topic!

In hal.h, we define the below for the deadband. Due to some of the modes we use our motor in, we need to update the deadband on the fly. Is this possible? We are using TMS320F28069M and DRV 8303.

Thanks!
Jonathan



_________________________________________________________________

//hal.h  This is where we define the deadband


//! \brief Defines the PWM deadband falling edge delay count (system clocks)

//!

#define HAL_PWM_DBFED_CNT         500 // 8205-725  8208-320

//! \brief Defines the PWM deadband rising edge delay count (system clocks)

//!

#define HAL_PWM_DBRED_CNT         500 // 8205-725  8208-320

______________________________________________________________________

//Main.c Below is a snipped where we are calling PWM functions

if(CTRL_isError(ctrlHandle)) {

            // set the enable controller flag to false

            CTRL_setFlag_enableCtrl(ctrlHandle,false);

            // set the enable system flag to false

            gMotorVars.Flag_enableSys = false;

            // disable the PWM

            HAL_disablePwm(halHandle);

        } else {

            // update the controller state

            bool flag_ctrlStateChanged = CTRL_updateState(ctrlHandle);

            // enable or disable the control

            CTRL_setFlag_enableCtrl(ctrlHandle, gMotorVars.Flag_Run_Identify);

            if(flag_ctrlStateChanged)

              {

                CTRL_State_e ctrlState = CTRL_getState(ctrlHandle);

                if(ctrlState == CTRL_State_OffLine)

                  {

                    // enable the PWM

                    HAL_enablePwm(halHandle);

                  }

                else if(ctrlState == CTRL_State_OnLine)

                  {

                    if(gMotorVars.Flag_enableOffsetcalc == true)

                    {

                      // update the ADC bias values

                      HAL_updateAdcBias(halHandle);

                    }

                    else

                    {

                      // set the current bias

                      HAL_setBias(halHandle,HAL_SensorType_Current,0,_IQ(I_A_offset));

                      HAL_setBias(halHandle,HAL_SensorType_Current,1,_IQ(I_B_offset));

                      HAL_setBias(halHandle,HAL_SensorType_Current,2,_IQ(I_C_offset));

                      // set the voltage bias

                      HAL_setBias(halHandle,HAL_SensorType_Voltage,0,_IQ(V_A_offset));

                      HAL_setBias(halHandle,HAL_SensorType_Voltage,1,_IQ(V_B_offset));

                      HAL_setBias(halHandle,HAL_SensorType_Voltage,2,_IQ(V_C_offset));

                    }

                    // Return the bias value for currents

                    gMotorVars.I_bias.value[0] = HAL_getBias(halHandle,HAL_SensorType_Current,0);

                    gMotorVars.I_bias.value[1] = HAL_getBias(halHandle,HAL_SensorType_Current,1);

                    gMotorVars.I_bias.value[2] = HAL_getBias(halHandle,HAL_SensorType_Current,2);

                    // Return the bias value for voltages

                    gMotorVars.V_bias.value[0] = HAL_getBias(halHandle,HAL_SensorType_Voltage,0);

                    gMotorVars.V_bias.value[1] = HAL_getBias(halHandle,HAL_SensorType_Voltage,1);

                    gMotorVars.V_bias.value[2] = HAL_getBias(halHandle,HAL_SensorType_Voltage,2);

                    // enable the PWM

                    HAL_enablePwm(halHandle);

                  }

                else if(ctrlState == CTRL_State_Idle)

                  {

                    // disable the PWM

                    HAL_disablePwm(halHandle);

                    gMotorVars.Flag_Run_Identify = false;

                  }

                if((CTRL_getFlag_enableUserMotorParams(ctrlHandle) == true) &&

                  (ctrlState > CTRL_State_Idle) &&

                  (gMotorVars.CtrlVersion.minor == 6))

                  {

                    // call this function to fix 1p6

                    USER_softwareUpdate1p6(ctrlHandle);

                  }

              }

        }

0 Jonathan Azevedo1 over 6 years ago in reply to Jonathan Azevedo1

Intellectual 412 points

Hello Hareesh,

Following up on the question above to see if it is possible to adjust the deaband time on the fly?

Best,

Jonathan

0 Yanming Luo over 6 years ago in reply to Jonathan Azevedo1

TI__Guru** 114200 points

You might have a look at the datasheet of DRV8303, the dead time of DRV8303 is programmed through DTC pin. A resistor is connected from DTC to ground to control the dead time which range is from 50 ns to 500 ns.

Of course, you can set dead time by changing the registers of F28069M as the following code in HAL_setupPwms() in hal.c. Replace the HAL_PWM_DBRED_CNT and HAL_PWM_DBFED_CNT with two variables, set these vairables to the dead time value, and call these code at any time you want. But the minium dead time will be limited to DRV8303.

// setup the Dead-Band Rising Edge Delay Register (DBRED)
PWM_setDeadBandRisingEdgeDelay(halHandle->pwmHandle[0],HAL_PWM_DBRED_CNT);

PWM_setDeadBandRisingEdgeDelay(halHandle->pwmHandle[1],HAL_PWM_DBRED_CNT);

PWM_setDeadBandRisingEdgeDelay(halHandle->pwmHandle[2],HAL_PWM_DBRED_CNT);

// setup the Dead-Band Falling Edge Delay Register (DBFED)
PWM_setDeadBandFallingEdgeDelay(halHandle->pwmHandle[0],HAL_PWM_DBFED_CNT);

PWM_setDeadBandFallingEdgeDelay(halHandle->pwmHandle[1],HAL_PWM_DBFED_CNT);

PWM_setDeadBandFallingEdgeDelay(halHandle->pwmHandle[2],HAL_PWM_DBFED_CNT);

0 Jonathan Azevedo1 over 6 years ago in reply to Yanming Luo

Intellectual 412 points

Thank you Yanming Luo,

We are now able to update the deadband in real-time, but are not calling the HAL_setupPwms() function. Does this need to also be called or can we just update via:

// setup the Dead-Band Rising Edge Delay Register (DBRED)
PWM_setDeadBandRisingEdgeDelay(halHandle->pwmHandle[0],HAL_PWM_DBRED_CNT);

PWM_setDeadBandRisingEdgeDelay(halHandle->pwmHandle[1],HAL_PWM_DBRED_CNT);

PWM_setDeadBandRisingEdgeDelay(halHandle->pwmHandle[2],HAL_PWM_DBRED_CNT);

// setup the Dead-Band Falling Edge Delay Register (DBFED)
PWM_setDeadBandFallingEdgeDelay(halHandle->pwmHandle[0],HAL_PWM_DBFED_CNT);

PWM_setDeadBandFallingEdgeDelay(halHandle->pwmHandle[1],HAL_PWM_DBFED_CNT);

PWM_setDeadBandFallingEdgeDelay(halHandle->pwmHandle[2],HAL_PWM_DBFED_CNT);

Although we are able to update on the fly, the motor at times seems unstable with the change. Is there anything else impacted by this change that we are leaving out?

Thanks!
Jonathan

0 Yanming Luo over 6 years ago in reply to Jonathan Azevedo1

TI__Guru** 114200 points

That's fine as the code above you mentioned, only call a part of the code in HAL_setupPwms().

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CCS/TMS320F28069M: How to change the PWM deadband falling/rising edge delay count