Question about VSG parameters change during the TDS

[xiaoheimai95]

Dear Dr. Cui and Jinning,
We want to modify the value of M and D of VSG unit during the TDS by the following code:

ss.TDS.config.tf = 2.0
ss.TDS.run()
ss.REGCV1.alter('M', REGCV1_10, 2)
ss.REGCV1.alter('D', REGCV1_10, 10)
ss.TDS.config.tf = 10
ss.TDS.run()

Can this method successfully modify the parameters of the VSG during the TDS process?

[jinningwang]

An easy way to test is that, after altering the parameter, using Model.get method to check if the value is changed.

[cuihantao]

Altering D should work as expected.

Altering M will not take effect in the current version. It is due to how time constants associated with differential equations are processed. You can tell from https://docs.andes.app/en/latest/groupdoc/RenGen.html#id16 that M is the time constant on the left side of differential equations T x' = f(x, y).

At the very beginning of simulations, left-hand-side time constants of differential equations are arranged into dae.Tf. To modify M, for now, you can do it in two steps:

First, do

ss.REGCV1.alter('M', REGCV1_10, 2)

to alter the value and store its per-unit value in ss.REGCV1.M.v.

Next, modify dae.Tf:

ss.dae.Tf[ss.REGCV1.dw.a] = ss.REGCV1.M.v

Edit: index dae.Tf by the address of the state, not the parameter.

[cuihantao]

The issue has been fixed on my latest develop branch. alter should work as expected without having to manually update dae.Tf.

[xiaoheimai95]

So if I install the former version of andes, I should use the above method to set up M. And if I update into the latest version of andes-develop, I just need to use the basic code ss.REGCV1.alter('M', REGCV1_10, 2) to set it up, right?

[cuihantao]

That is correct!

[xiaoheimai95]

Thanks a lot!