Experienced with PQ Control and PI Tuning for Inverter Power Control?

[GregoryGr]

Does anyone have experience modeling active/reactive management in an inverter? I'm working on it for a project, more precisely I'm trying to implement that PQ control with references of voltage, as is seen in this image:

Problem is I've tried many PI regulators, and my I_dq doesn't want to follow the references. Does anybody have experience either on PQ control or in PI tuning (I suppose there is software that can find the optimal PI values? )

 

[anorlunda]

How have you modeled the grid? The P and Q output is not determined entirely by the inverter, The grid's behavior plays a major role or even the dominant role.

How do you determine the zero degree reference angle in phase with Ed?

Where does actual system frequency come into play?

I_dq

What is that?

 

[GregoryGr]

How have you modeled the grid? The P and Q output is not determined entirely by the inverter, The grid's behavior plays a major role or even the dominant role.

How do you determine the zero degree reference angle in phase with Ed?

Where does actual system frequency come into play?What is that?

Hm, I haven't really modeled the grid, it's a fixated 3ph sine source with 400 polar voltage/50Hz and an inductance. What did you have in mind for the grid?

The approach was to orient the grid voltage so Vq = 0 as to use Iq and Id for decoupled power control (sensors are placed in the PCC). So in the image i posted in the modulator, the way i try to simulate it, is first to normalize Ed and Eq reference, and then dq->abc with the same angle the field orientation of the grid, which should in theory provide the necessary phase difference and amplitude to achieve PQ control...
(by Idq I meant both Id & Iq)

Thanks for the quick reply :)

 

[anorlunda]

Hm, I haven't really modeled the grid, it's a fixated 3ph sine source with 400 polar voltage/50Hz and an inductance. What did you have in mind for the grid?

See this PF Insights article, especially the equations that describe P and Q flow between two adjacent nodes in a grid.
https://www.physicsforums.com/insights/ac-power-analysis-part-2-network-analysis/

I think your inverter would work better by imitating conventional power plant controls. One loop to control real power by adjusting phase angle. Another loop to control voltage magnitude and therefore Q.

Control loops feeding back Id and Iq rather than V and $\theta$ sound strange to an old-timer like me.

 

[GregoryGr]

Thank you, I will check this out. What you are suggesting I am currently experimenting with (and even though I haven't managed to work it out, it seems to be responding in the right direction! ). Truth be told, current control without classic hysterysis or bandwidth control seems strange to me too, but it seems to have worked in some papers... The reason I'm attempting that is because in general field control should have a better response.

The topic of my project is about DER sources, so convetional power controls should be on point!