Configuring ePWM block for 3phase inverter for TI28335 DSP in SIMULINK

Hi I am using TI 28335 experimenters kit (I am pretty new to it) to design an experiment for 3-phase inverters. But I am not able to configure the ePWM block in SIMULINK for this. I am taking current as input to this DSP and PWM as output. The inverter kit that I use is designed to accept complementary signals with dead time of around 2microsec on each leg. Some of the problems that I have are

#1 How do I produce complementary outputs from each module. Should I enable both ePWMA/ePWMB and also check use deadband for both of these? When I enter deadband value RED or FED, what is unit for these (0-1023)? Are they in seconds or what?

#2 How do I sync the outputs? I think I need to SYNCI of ePWMA to an external pin and connect SYNCO of ePWM1 to SYNCI of ePWM2 and SYNCO of ePWM2 to SYNCI of ePWM3 (with zero phase difference). But I am not able to configure it from ePWM block parameters. Which parameters should I change?

#3 There should be some problem due to time delay in input from ADC and PWM output. If yes, how can I handle it?

[Z TJ]

Hi, from knowledge I know:

1.You can see the help to understand how to realize complementary signal.It's very easy. RED and FED, the unit is processor cycle, for 28335, if 150M, one presents 1/150M (6.67ns).

2.About the sync of PWM module,you can refer the model in the attachment.

3.What's mean about the delay? You can calculation in the PWM cycle,and update the value in the next PWM cycle.

[Seyedfoad Taghizadeh]

Hi ZTJ

I have the same problem with the same DSP. Would you please help me with the synchronization of the ePWM blocks?

Thanks Foad

[abolfazl mortazavi]

Hi

I could create two synchronized PWM. In order to do that, you should consider that PWM1 has SYNCO set to CTR=Zero and PWM2 has SYNCIN enabled and phase shift set to zero.

Regards,

Abolfazl

[Mohammad Tauquir Iqbal]

its all because of deadband use epWM of less than 50 % duty cycle at ePWM and ePWMB.

updown counter.

time period - 64000

cmpa - 3300

cmpb - 3100

ePWMA - set up cmpu. clear down cmpd

ePWMB - set up cmpd . clear cmpu.

hope it workds.

no deadband used.

[Mohammad Tauquir Iqbal]

https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/725974?LAUNCHXL-F28069M-Deadband-for-ePWM-in-Simulink-and-EPWMxB-enable