Yes!
adding cap to L2 on low side (both sides a cap) did work.

let's think this over
it only works with L2 having double frequency if the impulses, why not single frequency?

impulse does not show up on other side of coil. Does it still show up in the middle of the bifilar pancake coil?

Wait... is the cap only charging and discharging? doesn't the coil do anything? nooo? yes? hmmm


orange is low side of coil/cap
yellow is high side of coil/cap

yes makes sense if you look at the square wave signals.
1 impulse per period. not 2.

I could test with both mosfets turned of, with alternating overlap at turn of.
but that would leave series resonant L2 ungrounded, only referenced to L1.

and how would those 2 square waves look..
same dead and on time, but one switches off little before the other, and that alternates? eh... how?

its nice but... does it really work? does L3 still get a kick?
one impulse enters in outside rim
other on inside rim.

I want both on inside rim. or doesn't that matter...?

FOOOD

If we take a look at the process of close coupled L1 and L2,
whereby L1 creates an impulse (due to its relatively high resonant frequency)
that feeds into series resonant L2,

we can see, L1 needs to be charged up, to produce a magnetic field.

then the switch is opened, and the magnetic field energy transforms (at the speed of its resonant frequency) into an inductive spike impulse.

The impulse is fed into series resonant L2 (low impedance path to ground).

Series resonant L2 is amplified by the impulse energy of L1.

And this amplified L2 is close coupled to L1.
amplified L2 is assisting L1 with the build up of its new magnetic field.

Now with a single impulse per period, we can't do this continuously. We need 2 impulses per period. each new magnetic field of L1 needs to have a impulse before it is build up.

This way you can have a continuous build up of energy.

with a single switch, a single impulse per period, you can't do this.

L1 is not building up its magnetic field for half of the period. the impulse is thus not assisting L1.

That's why we need the half bridge.
Because it produces 2 impulses per period. and each impulse into L2, is followed by a magnetic field build up in L2 AND L1.

I hope you all understand what I say here.
this is the cycle, whereby the energy of the previous cycle, is REcycled upon the next new cycle. This creates an energy build up.

this is able to overcome the losses in resistance.

but only if each maximum of L2 has its own impulse. It is vital to realize this.

The impulse is very fast, and it tranfers energy very fast from L1 into L2.
then the relative slower process of the build up of the magnetic field of both L1 and L2 follows.

the impulse is the longitudinal movement of the field energy. (relative fast)
the magnetic field of L1 and L2 is the transverse field energy. (relative slow).

IGBT is a dead end.
turn off tail is unavoidable making proper impulses is not for IGBTs. Especially in half bridge configuration, where they also have extreme oscillationts due to internal capacity and inductance.

I found a way to make a mosfet half bridge working. diode, between mosfet and power supply, blocks impulse that paase through body diode. cooling is needed, its not ideal, but far better then IGBT's.

I'll make a new thread again.
https://open-source-energy.org/?topic=3576