Inverter voltage and current loops

Jayvie Gabriel Templonuevo

Hi!

I'm creating a grid connected inverter. The DC source will later be changed to a PV with buck boost but as of now, I'm testing it with a DC source to tune the PR controllers. The Current PR controller was taken from the PSIM sample of PLL (z-domain) and I copied it for the voltage PR controller. However, following the equation of the PR contorller kp+(kr*s)/(s^2+w^2), is it a similar implementation as well for the voltage loop?

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NikosDimitrakopoulos

Dear Jayvie,

Are we talking about a stable AC gird at the output? If so, the AC voltage is imposed by the grid. The inverter cannot control the grid voltage; it can only respond to it. You have the ability to control the exchanged power to the grid by controlling the current.

When it comes to the DC side, the inverter might need to control the DC link voltage to ensure proper operation and maximum power point tracking (MPPT) when connected to a PV source. There are relevant examples within PSIM.

For grid link connected system tutorials, I would highly recommend this video:

https://www.youtube.com/watch?v=HbT_huAvL28

The tutorial also portrays the use of SmartCtrl to come up with the controller gains in a semi-automatic way.

Hope this helps!

BR,

Nikos Dimitrakopoulos