Arduino due - problem with dead time

Dear all,

I have been trying to implement dead time on the Arduino Due board using complementary PWM outputs in order to control H-bridge inverter. On the first view, my program code works, but not completely correct. Actually, two problem are appeared :

  • at the beginning and in the end of the output signals I get overlaps - dead time in this two points does not have reaction
  • if I adjust constant modulation signal instead of sin, every some time I can see bigger value of the dead time than adjusted value in the program code.

Does anybody know how I can solve this problem? Maybe, I cannot see some detail which makes this problem.

One part of my program code is :

PWMC_ConfigureChannelExt(PWM, 0, PWM_CMR_CPRE_CLKA, PWM_CMR_CALG, 0, PWM_CMR_CES, PWM_CMR_DTE, 0, 0); PWMC_SetPeriod(PWM, 0, cprd); PWMC_SetDutyCycle(PWM, 0, Ton1); PWMC_SetDeadTime(PWM, 0, DeadTimeHigh, DeadTimeLow);

Thank you.

Milan UNIBO

Does anybody know how I can solve this problem?

Without seeing your code? No.

This belongs in the Due section.

Here is my program code, for channel 0 :

float x = 0; // argument of the sine function
const float pi = 3.1415;
int i = 0;
int k = 0;
float carrierfreq = 4000; // Carrier frequency
float modfreq = 50; // Modulation frequency
float ris = carrierfreq / modfreq; // points where the sine function is divided
float Ton1 = 0; // ignition time, random initialization
int DeadTimeHigh = 500;
int DeadTimeLow = 500;
float lookup1[2500];
int clkfreq = 42000000;
float cprd = (clkfreq /(carrierfreq*2));

void lookuptable() {
for (i = 0; i <= ris; i++) {
lookup1 = sin(x);
_ x = x + 2 * pi / ris;_

  • }*
    }
    void PWM_Handler(void)
    {

  • PWM->PWM_ISR2;*
    _ Ton1 = abs(lookup1[k + 1]) * cprd;_

  • if (lookup1[k + 1] >= 0) {*

  • PWM->PWM_CH_NUM[0].PWM_CDTYUPD = Ton1;*

  • PWM->PWM_CH_NUM[0].PWM_DTUPD = DeadTimeHigh;*

  • }*

  • else {*

  • PWM->PWM_CH_NUM[0].PWM_CDTYUPD = 0;*

  • PWM->PWM_CH_NUM[0].PWM_DTUPD = DeadTimeLow;*

  • }*

  • if ((k + 1) < ris) {*

  • k++;*

  • }*

  • else {*

  • k = 0;*

  • }*
    }
    void setPWMpin(uint32_t pin) {

  • PIO_Configure(g_APinDescription[pin].pPort,*

  • PIO_PERIPH_B,*

  • g_APinDescription[pin].ulPin,*

  • g_APinDescription[pin].ulPinConfiguration);*
    }
    void setup() {

  • Serial.begin(9600);*

  • lookuptable(); // calling the function to be done*

  • // Making active desired PWM pin*

  • setPWMpin(34); //PWML0*

  • setPWMpin(35); //PWMH0*

  • pmc_enable_periph_clk(ID_PWM);*

  • PWMC_DisableChannel(PWM, 0); *

  • PWMC_ConfigureClocks(clkfreq, 0, VARIANT_MCK);*

  • PWMC_ConfigureSyncChannel (PWM, PWM_SCM_SYNC0, PWM_SCM_UPDM_MODE1, 0, 0);*

  • PWMC_ConfigureChannelExt(PWM,*

  • 0, *

  • PWM_CMR_CPRE_CLKA, *

  • PWM_CMR_CALG, *

  • 0, *

  • PWM_CMR_CES, *

  • PWM_CMR_DTE, *

  • 0, *

  • 0); *

  • PWMC_SetPeriod(PWM, 0, cprd); *

  • PWMC_SetDutyCycle(PWM, 0, Ton1); *

  • PWMC_SetDeadTime(PWM, 0, DeadTimeHigh, DeadTimeLow);*

  • PWMC_EnableChannel(PWM,0); // Enabling the channel 0*

  • NVIC_DisableIRQ(PWM_IRQn);*

  • NVIC_ClearPendingIRQ(PWM_IRQn);*

  • NVIC_SetPriority(PWM_IRQn, 0);*

  • NVIC_EnableIRQ(PWM_IRQn);*

  • PWMC_EnableIt(PWM, 0, PWM_IER2_WRDY);*
    }
    void loop() {

  • Serial.println(34);*
    }

Thank you!

Thank you!