Hi, I'm trying to design a power inverter for solar panels. I'm out of school doing this on my own so any help would be appreciated.
It would be 450V going to a boost converter, to a DC link capacitor, and then the inverter, followed by an LCL filter.
The equation for a DC link capacitor, based on the target voltage ripple is:
C=duty/(R*Vripple*f_sw)
Where D is duty, f_sw is switching frequency, Vripple is the ripple (delta Vo/Vo) going into the inverter, and R is the resistance of the load. Well the load in this case is a switching inverter going into an LCL filter going into a 10 ohm load, so it's not intuitive as to what the resistance is.
My question is how do I calculate even a rough idea of what this resistance might be?'
If you need to know my specific design requirements, the output will be 2kVA on a 10 ohm load, target efficiency is 95%. Input is 450V (although could vary from 360V to 540V depending on sunlight) on a 10 Ohm load.
One thing I tried was ohms law: (450V)^2/(2000VA) = ~750 Ohms. I'm not sure if that's right.