YARO,
I posted the same circuit on page two of this post!This can be done by connecting 2 ignition coils primaries in parallel but of opposite polarity: Shown here:
http://www.rmcybernetics.com/projects/DIY_Devices/homemade_ignition_coil_driver.htm (SECOND CIRCUIT DOWN)
And believe it or not, you can actutally drive the ignition coils with a PWM, but they don't like kHz frequencies unless you get some high performance ones, even then a 15,000RPMX 8 cylinders=120,000/60=2000Hz.The higher you go the hotter the coil will get, and it won't be long before you burn it up!
It would be hard to achieve resonance with these coils(unless you build your cap and chokes to resonante at 1kHz or lower). If not your coils will heat up very quickly!!! I know cuase I've already played with ignition coils and given up on them. It's more practical to use one transformer than two ignition coils..
IF you have a 15 amp or larger PWM there's no need for all the transistors shown in the circuit.
The circuit below shows how you can drive the coils with a pwm. The .001uF cap is to absorb the HV BEMF spikes from the coil. This protects your PWM's MOSFET or TRANSISTOR, which ever you are using.
(http://i51.photobucket.com/albums/f389/xbradkx/Dualigncoildriver.jpg)
One thing I would say though, is stan worked on this stuff for years, he's probably tried all these types of things we think will work, but in the end the process he shows is the most simple, and most efficient way of doing it. I've you've got the money this might be worth building to play around with, but If you want to actutally replicate Stan you should build it the way he shows.
-That's my 2 cents
