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Implementing supervisory control via DLL in PSIM (real-time synchronization issue)

Hello,

I’m trying to implement a supervisory control system using optimization codes in PSIM to generate the reference signals for converters in the simulation environment. The optimization code is written in C++ and implemented as a DLL block in PSIM. I’m using the Gurobi solver to handle the energy management optimization problem.

My issue is that the converter-level (primary) controllers in the simulation run with a time step of 1 μs, while the supervisory control operates with a time step of 15 minutes. I’m wondering how I can properly integrate this high-level controller and synchronize it with the local controllers to apply the converter setpoints.

I’m looking for an approach that is as close to real-time implementation as possible, I’ve already tested an offline version before.

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NikosDimitrakopoulos

Hi @Nasrin90,

This is a very interesting question! I have a few comments:

1. I’m curious if the Gurobi library is bundled together with your DLL, or if it’s somehow linked separately at runtime in PSIM?

2. In my understanding the energy management has a long time constant →15 minutes which is a very long for a switching simulation that is solving with a small time step to capture switching effects. In these cases, we want to avoid the small time step by omitting switching effects. What type of converters are you simulating? PSIM is offering an average model for an inverter that will allow you to do that:

This model is essentially a set of controlled sources, producing ideal AC waveforms. The problem is that we cannot have such models for complex converter topologies.

3. In this case, a Neural Network trained with PSIM results can be used to map the performance of the converter, capturing dynamics, but omitting switching ripple. We can leverage Altair romAI to build this NN without scripting. Please take a look at the following articles and let me know what you think:

Looking forward to your feedback.

BR
Nikos D.

Nasrin90

Hi @NikosDimitrakopoulos

Thanks for your comment.

1- The Gurobi library is bundled within my DLL block; there is no solver linked separately in PSIM. Everything is contained in the DLL, which is connected to my inverter model.

2- You’re right, the main issue here is the time synchronization between the EMS and the primary control. Thank you for suggesting the average model. However, my system is quite complex, and I’d also like to explicitly demonstrate the EMS implementation and its performance in a simulation that includes switching effects.

3- That’s an interesting idea! I think it might be helpful, though perhaps not a comprehensive solution. If separate training is required for each model, that could introduce additional complexity. However, this is just my initial thought, we may need to discuss it further. I’ll review the articles and update you afterward.

In the meantime, I’d appreciate any suggestions you might have that could help in this regard.

Best
Nasrin

NikosDimitrakopoulos

Hi @Nasrin90,

Thank you for clarifying. During the 15min intervals, is steady state achieved, or things are changing in the simulation?

Let me also suggest a very helpful webinar on the topic:

AI Surrogate Models of Power Converters with Altair romAI | Webinar Recording

In this one we used NNs for a battery charging application which also includes long time constants.
I will also include my colleague @RSGarciarivas in this discussion to provide insights regarding the training process.

15 minutes, is a really long time for power electronics and if you don't replace the switching model with something else I cannot see a way to speed up your analysis.

To be able to support you more effectively and be able to share more information within a confidential portal, please consider creating a ticket in our Customer Support Portal:
https://support.altair.com/csm

BR
Nikos D.

RSGarciarivas

Hi @Nasrin90. Training AI ROMs with Altair romAI requires separate training, but that is a well-documented, straightforward process. Apart from the resources Nikos shared, you might find these useful:

Accelerating Battery Charging Simulations with Altair romAI - Part 1 - Altair Community

Creating Datasets from Results Files for Altair romAI - Altair Community

Rafael

Nasrin90

Thanks @NikosDimitrakopoulos for providing more information. I would like to discuss it more within a confidential portal, I may be able to explain the details better. But I could not create a ticket through the portal I get the following comment when I use the address you provided:

"Technical Support via our case management system is not enabled on your account."

Thanks @RSGarciarivas for providing more information which is really interesting, I will check out them.

Best
Nasrin