Three phase y-d transformer for a pfc rectifier

Hello,

I’m trying to implement a rectifier with a grid voltage of 50V that feeds into a three phase wye-delta transformer with the ratings of 250VA and 50Y/25delta. In the attached simulation I set the line-line(rms) voltage to 61.23V and I observed the phase voltage on the primary side as 50V and the secondary side 25V which is the desired voltage but the sine wave has a lot of distortions. I didn’t use the exact inductance and resistance values of the transformer so I’m not sure if that’s why I’m getting a distorted sine wave on the secondary output voltage from the transformer.

Can someone provide me with some insight? It would be nice if PSIM can include a examples folder on transformers for grid connected systems.

Thanks,

Nadia

Attached is the revised psim file

Hi Nadia,

If you use a smaller timestep you’ll see that the “noise” is a result of your switching. Try with 1us, also, in this simulation the “print step” is step to 3 which only saves every third simulation data point, this is abstracting away some of the detail.

With regards to Tx parameters, it isn’t essentially to get the correct parameters, ballpark is fine for most simulations. It will be very clear if things aren’t working properly as the results will not be correct at all.

For grid connected examples there is a cycloconverter in the ac-ac folder or the harmonic cancellation examples in the AC-DC folder.

I hope this helps.