> http://ww1.microchip.com/downloads/en/AppNotes/01444A.pdf
>
> An app note on using a dsPic in a grid feed converter. Appears to be base=
d
> around a 250W solar panel.
>
> Has info for both 120V/60Hz and 230V/50Hz.
>

Interesting! I wonder about the simplified model in figure 1. Do they
really need both Rp and Rs? It seems that the current source and Rp could
be converted to a Thevenin equivalent, which would be a voltage source
with a series resistance. That series resistance would then be in series
with Rs. So, it seems the equivalent circuit could be either a Norton
circuit (current source with Rp) or Thevenin circuit (voltage source and
Rs).

The active clamp circuit in the flyback converters is interesting. I've
not seen that before.

The H bridge FET driver circuit is interesting. They send high frequency
through a transformer, then rectify it to drive the gate. They then use an
opto coupler to pull the gate back down when turning off the FETs.

The MPPT tracking is interesting. They're using the "disturb and observe"
method. I used that in a solar car charger many years ago. I wonder if
that's a whole lot better than the somewhat simpler "regulate the input
voltage" method that LTC uses in their designs. Figure 2 shows the MPPT
changing by 10V under various illumination conditions.

I think it's a pretty impressive application note! There's a lot of detail
in making one of these things!

Harold




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