Question about VSG unit modify

[xiaoheimai95]

Dear Dr.Cui and Jinning,
I added the current limit in the VSGOuterPIModel：

However, the simulation results does not reflect the current limit, I would like to ask what the problem is?

[jinningwang]

[Update]

There can be a simpler way to determine the effects of the current limit. You can use two systems with the same disturbance. One system has REGCV2 and the other has REGCV3.

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In these figures, it is hard to determine whether the current limit is in effect or not. I would suggest giving a benchmark curve that compares similar variables from REGCV2. Let's say, plotting out REGCV2.Idref and REGCV3.Idref. This means you might also need a REGCV2 device in your case.

[cuihantao]

Yeah, as always, you want to test it in two steps:

1. Apply it to the original model to make sure the outcome is expected. This step makes sure the parameters are good.
2. Apply the same disturbance to your modified model. Compare the outputs (currents, in this case).

[xiaoheimai95]

Dr. Cui, there is still a small question. When I set up the SMIB system according to the above methods, although the current limitation can be triggered, there will be initialization problems. Is this normal?

[jinningwang]

The failed initialization can occur when developing a new model. In your case, it seems to be caused by unbalanced initialization equations. There are some discussions on similar topics that might be helpful for you.

Dr. Cui, there is still a small question. When I set up the SMIB system according to the above methods, although the current limitation can be triggered, there will be initialization problems. Is this normal?

[xiaoheimai95]

Dear Jinning,
Thanks for your answering, in my code, I did modify the PIId、PIIq and udref、uqref equation by change the PIvd_y、 PIvq_yinto Idref_y、 Iqref_y because the current limitation and it is the only change I have made in this part.

[xiaoheimai95]

Here is my log of init.
init_debug.txt

[cuihantao]

The other possible cause is that the initialized values calculated from the initialization equations are out of the limits you set.

You can check the variables on which your new limits are imposed, then compare the initialized values (logged in init_debug.txt) with the limits.