Hello, there is not very much known about the specific implementation details of the KERS systems currently in use, but general information could be found here:
http://www.f1technical.net/features/11805
http://www.williamshybridpower.com/technology/
viewtopic.php?f=4&t=3619
viewtopic.php?f=4&t=6714
viewtopic.php?f=4&t=6305
For more info look under Engine, transmission and controls forum
viewforum.php?f=4&start=120
You could use the search function at the top of the site.
For info how to design this kind of systems i recommend you to look for "Handbook of automotive power electronics and motor drives" by Ali Emadi.
Good luck

"We will have to wait and see".