Yes, I know about using FETs, transistors, op-amps etc, if this thing actually works, go on and find out how to implement a PLL equivalent but also would use a microcontroller for reading the inputs and outputs (temperature, water and gas flow, current and voltage etc) and control the circuit.
I have put together a basic PWM driver circuit using opamps, schmitt triggers, variable resistors, this is linked to a FET that drives the transformer.
I am in the process of getting very fast and high power diodes, still trying to find a source for UU and UI cores but that will happen soon. I already have my 28 SWG wire that I will use.
I should probably make a coil winding jig, I also recently bought a rotary counter that I could use to count the turns if I connect it to the shaft the coil is wound on then I dont have to remember and can just focus on feeding the wire properly.
If possible, I would use the microcontroller for locking onto the required resonance frequency and also to generate the required frequency. Events such as sudden current spikes etc from changes in the water (maybe due to changes in concentrations of dissolved compounds and/or changes in water flow rate) should also be measured so the chip can be thriggered into locking onto the required frequency.
So I have not done much with PLLs but that can be done with descrete chips (like a LM565 I think) and Im sure microcontrollers can do it.
There is only a reason to go to PLLs if the concept works so I want to check that first and if it does then I will find out how to do it in a practical way (I have learned some theory but that does not help as much in a practical world)