CCS/TMDSSOLARUINVKIT: C2000 micro inverter questions

That Res is primarily to prevent any damage to the AC source and also in certain labs we are not allowed to feed power back into the grid. Using that resistance prevents us from feeding power back into the grid. 

Hence, at 220Vrms the 200 Ohms load should be ok. 

Also refer to the note on that page for more details. 

If we don't use AC source and connect the output of micro inverter with 220Vrms grid directly, do we still need to use a resistive load of 200 Ohms?

We have not performed that test, nor guarentee it working under that condition ( i do not have 220Vrms where I am in the US) . Refer to the UG.

You can perform your own experiment under those conditions.

I see. Does it also mean that "..~240W (max) if connecting to 220Vrms.." is under this test? That is, using 200 Ohms Power resistor with 220Vrsm output AC source to test max. power which reaches 240W.

240Max is the rating of the inveretr stage at 220Vrms,

The selection of the res was done to match that power, not vice versa.

Thanks. May I know what is the maximum power rating of Flyback stage(single)?

it's 250w,

How to increase the inverter stage to 250W with 110Vrms, 60Hz grid?

I am not sure what exactly your question is, we do test upto 200W output at 100Vrms grid. Though the eff is not good at that point.

www.ti.com/.../tidu405b.pdf

To change power ratings, improve performance, etc, typicall you need to understand the schematic and then see what components are not rated for the voltage and current. Including sensing range of sensors etc. Once you have performed this analysis, you will know a path forward.

Next part is to update sw and test.

In section 2.4 on page 12 of "tidu405b.pdf", it mentions "Output power: 280 W @ 220Vac, 140 W @ 110Vac" so that's why I asked the question. It seems to me that you have tested upto 200W output at 100Vrms grid. What is the maximum output power with 110Vrms, 60Hz? My target is 300W anyway.

I am going to assign this thread to the person who did the HW design to clarify absolute max's

For max power output pls use the spec and limit it to 140W at 110Vac. For 220Vac, the power will be limited to 280W.  

Shamim

On page 5 of QSG, it mentioned "With the EVM powered OFF, connect a resistive load of 200Ohms to the EVM AC output terminals (TP15 & TP16) when connecting to 220Vrms Grid,..". May I know what the resistive load of 200Ohms is used for with 220Vrms Grid?

This has been explained in the Note that immediately follows. We did not have a 220V grid in the lab. And so it was tested with an emulated grid. This emulated grid was created by an AC source and a 200 ohm resistor.

Shamim