Linearization in GFM-based power system

Hello,

I have a system (depicted above) consisting in a GFM converter (including current limiter) connected to an equivalent representation (synchronous generator + load) through a coupling transformer and transmission lines. The control used is virtual synchronous machine (1 / (2*H*s + D)). I want to tune the parameters H and D using particle swarm optimization. To do that I want to find a metric that is really fast (without time-domain simulations). What I am trying to do is to linearize the system between the red dot (input) and the blue dot (output) and to compute a fitness function that aims to keep the phase and gain margins in a desired range.

However it seems that the linearization (with the function linearize) doesn't work well. There are lots of simscape blocks used in the model, could it be possible that some are not compatible with linearization? Or what could improve the linearization? Are there other metrics that could be used and are fast to compute and don't require time domain simulations?

Thank you

Answer 1

[Arushi]

Hi Lucas,

Based on my experience with similar setups, I recommend using the Linearization Manager (Model Linearizer) in Simulink for a more interactive approach and provide a way to select linearization points and analyse the results. Here is the link: https://www.mathworks.com/help/slcontrol/ug/modellinearizer-app.html

For models with Simscape blocks, the linearization process can be a bit different compared to standard Simulink blocks. Here is the documentation for Simscape model linearization : https://www.mathworks.com/help/slcontrol/ug/linearize-simscape-networks.html

Hope this helps!