Hello,

First of all, what kind of a filter do you use between inverter and grid?

If it is an LCL type filter, it depends on where you close the loop.

The passive filter elements along the path cause voltage drop and phase shift depending on how big they are.

Give the details about your filter and I can give deeper answers then.

I have used  a single inductor for each phase  with a value of 3mH while connecting inverter output to grid

Hi,

If you are only facing problem in tracking Iq, a possible reason could be the DC voltage you are operating on. To track Iq>0 (i.e. PF < 1) you need higher dc voltages. Please see the reference:

Y. DENiZ, “Commissioning of a 30 kVA Variable-Speed, Direct-Drive Wind Power Plant,” University of Colorado, 1999.

Hi,

We should be talking about pu basis rather than real values. Anyway, 4% or 0.04 pu should be more or less the max value for the inductance so that no excessive voltage drop or phase shift occurs (size and losses also confines it likewise).

All in all, regarding the amount of inductance above, it is safe to set q-controller variable to zero.

Please find attached part of my thesis for the relevant q-axis tracking. I was using LCL filter and it was important to set the correct value of Iq set value depending on which side the feedback loop was closed.

So, your problem must be about the voltage drop on the inductors. Try increasing the DC input value to the inverter or try decreasing the inductance just so you confine the problem within a predictable region.

Regards,

Emre

How did you set Id*?@ Maulik Kandpal