RE: What is the pupose of ESc capacitors?
The particular board I am working on is more for power grid level conversion of energy. It can be used for either converting high voltage AC (pre transformer power line stuff) to mid level DC (200 - 450 VDC at 50 or so amps) or for converting high energy DC (say from a wind farm or solar panel array) to AC that can be fed onto the grid for distribution. (I didn't design this particular system - that was done by one of my colleagues who was with NREL (the National Renewable Energy Laboratory) before they downsized - I am just doing the layout.)
We also do electric vehicles - my other current main project is an electric pickup (380V Lithium Ion battery pack with a 120 hp motor - it should be wheels on the ground in the next couple of weeks). We have also done electric bus systems for a couple of cities so they can have non-polluting vehicles for walking mall shuttles and such. It's actually kind of a cool place to work