TMS320F28379D: Sycnronization problem of ePWMs in SIMULINK

Ege Ugur

Part Number: TMS320F28379D

Tool/software:

Hello,

I am generating a total of 3 ePWMs from the DSP, and 2 of them are sinusoidal ePWMs (SPWM) signals, one is a constant ePWM, from MATLAB SIMULINK.

I am facing an issue with changing the shape of PWM signals. After some time, the PWM signals start to change it's shape without having any feedback or closed-loop design.

I shared the oscilloscope images; you can see the changes clearly. Those signals are taken from the output of the logic gates. (The signals are also changing once I measured them from the DSP pins.)

I also shared the configurations of the ePWM (the first 5 images are for ePWM1) blocks. I synchronized ePWM1 and ePWM2, but it is still changing its shape. What could be the issue here?

29 days ago

0 Allison Nguyen 29 days ago

TI__Mastermind 23230 points

Hello,

Please take a look at MathWorks FAQ at this link below:

If you have further questions, the best way to get support on MathWorks products is to contact MathWorks live tech support.

You can also search for answers or post a question on MATLAB Answers C2000 forum. Additionally, there is info on MathWorks support C2000 in Documentation and Examples.

I will close the thread from here as the software is supported by MathWorks team on their forum.

Best Regards,

Allison

0 Aditya Dholakia 28 days ago

TI__Expert 7090 points

Hi,

From a quick check on the configuration setting that you've made, it seems your deadband is way too high for the time base period that you've provided. And since the duty is variable, you are bound to see significant variation in the EPWMB output.

Second tip - If you are going to go with the complementary PWM setting, I'd suggest avoiding all configurations relating to EPWMB in Counter Compare and EPWMB tab, since anyways they would be over-ridden by the deadband module. Please go over the EPWM block diagram to understand the workflow in case of a complementary output configuration.

As Allison pointed out, it'd be good to check with MathWorks if this still doesn't help.

Thanks,
Aditya

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TMS320F28379D: Sycnronization problem of ePWMs in SIMULINK