Linearising a plant that has the 3 phase PLL block

I have a model which uses a 3 phase PLL block.

I want to linearise this model using linmod and then use the A matrix to get the eigenvalues.

But when I do it. I get an "A" matrix that has a lot of NaNs.

Is there a workaround for this issue?

[John D'Errico]

There is almost always a workaround.

You can write better code, that is based on a careful understanding of numerical analysis, numerical methods, and floating point arithmetic as it is implemented using double precision.

Do you want a less vague answer? If so, then you need to show what you are doing. Not just a vague description. All that we know from what you said so far are the results. You got NaNs out. That means you wrote code that did not deal well with the numerical issues. So all we can intelligently say so far is to write better code.

The crystal ball is cloudy today. That is all it tells me.

[ck12345]

Thanks for you response.

The code I wrote is fine. i.e. When I run the code without the PLL block LINMOD works fine and I get the expected A matrix and the correct Eigen values.

The only time I get an issue is when I add the 3 phase PLL block from the simulink library.

This is when I get all the NaNs.

Running the simulation works fine. The only issue is LINMOD has trouble linearising the library 3PH PLL block.