Compiler/LAUNCHXL-F28377S: Phase shift problems variable PWM

Gauthier Mervillie

Part Number: LAUNCHXL-F28377S

Tool/software: TI C/C++ Compiler

Hello everyone,

I have a problem concerning the modulation of my PWM signal. I'm using MATLAB and SIMULINK to acquire a variable PWM signal. I was able to generate three similar variable PWM signals thanks to the synchronisation option. Now, I wanted to implement a phase difference of 120° on the signal, but this is not possible. The 120° phase difference I get, is on the PWM puls itself and not on the simulated sine wave. Of course I want this phase difference on the simulated sine wave and not on the pulses. How should I solve this issue? Should I use another DMA channel or can I still use the phase offset which I was using before?

Thanks in advance!

over 6 years ago

0 Subrahmanya over 6 years ago

TI__Mastermind 24095 points

Hi,

Your understanding is correct - the synchronization inside the PWM using TBPHS register works across PWM signals.
It doesn't directly address the phase shift needed at the sine wave output.
You have to achieve that in your system software using modulation of different PWM modules for corresponding phase shift needed on the output.
You can refer to any of the motor related examples on controlSuite for software - as they all would have some sine modulation.
I'm not familiar with the SImulink setup to achieve this. For that you can reach out to Mathworks support.
The main link for MathWorks Support is: http://www.mathworks.com/support/

Also see if this link helps - https://www.mathworks.com/videos/motor-control-with-embedded-coder-and-tis-c2000-107667.html

C2000™︎ microcontrollers

C2000 microcontrollers forum

Compiler/LAUNCHXL-F28377S: Phase shift problems variable PWM