External mode error 28379D

I am trying to implement voltage control for a buck converter. I am using ADC pins on my 28379D launchpad to read the output voltage of my buck converter. I am then implementing the control as shown in figure below. I am then using the digital output pin GPIO DO to output the PWM.

I am using fixed step in the solver with step size being 1e-7. I am using 1e-7 because otherwise the signal generator does not output a proper sawtooth signal. With this step size I get the following error

But if I use auto step size the external mode runs. The problem is the signal generator does not output a proper sawtooth. I get more of a triangle wave. And I dont see any output at the GPIO DO pin.

Can anyone help me sort this issue? Or you can also suggest me a different approach to implementing the control.

Thanks,

Akarsh M

Answer 1

[Dr. Pemendra Kumar Pardhi]

I have same problem in close loop operation of VSI when PI controller is used from discrete library. I think as per your model you need to use PID(PI and D=0) controller from C28X DMC library with selection of data type conversion after ADC scaling block.

If you have already solve this problem than provide the solution sothat it will be help full for someone

Thanks

Pemendra Pardhi