This is an old thread, but I'm interested to learn more about this topic.
My answers
1.) What the generate electric energy for spark plug?
coil (inductive ignition)
2.) What is the source of energy?
car battery with alternator
3.) What is the structure?
transistor, in most cases an IGBT
Part of the answer appears to be in this document link posted earlier.
http://argent.fia.com/web/appeloffre.ns ... finale.pdf
>>> 8 off inductive ignition drives
But we can look elsewhere, such as the Bosch Motorsport catalog from 2008, and search for "Single Fire Coil S16" or just search the document for "formula 1".
https://www.bosch-motorsport.com/media/ ... g_2008.pdf
You can also search the Bosch Motorsport catalog for 2013, search for "Single Fire Coil S19".
https://www.bosch-motorsport.com/media/ ... g_2013.pdf
Reading the description and specifications, it seems clear that these are very high performance inductive ignition coils, with coil on plug design, and in the case of the Single Fire Coil S19, rated to provide a 25A primary current with a 12V supply and a dwell time of just over 0.6 mS, or faster with a higher voltage.
There can be advantages of CDI, possibly faster rise times, useful for engines with forced induction and rich fuel/air mixtures, including alcohol fuels used in IndyCar and other series.
On the other hand, a modern inductive coil based system should be able to provide a longer duration spark, which is considered to be an advantage, especially when using lean fuel/air mixtures.
Disclaimer: The above is for 1989-2013 naturally aspirated cars, no idea what is used in post 2014 Formula One with Turbulent Jet Ignition (TJI) where the mixture in the pre-chamber can be quite rich.