R11 is too large. It should be about 2k.

There may be a problem with the inductor.
Since you are using an unknown inductor it's difficult to determine what it's doing.
If the inductance is too small it could give the results you are seeing.
Run the simulation with a 100μH inductor to see what I mean.

So you may need a larger inductor, or operate the circuit at a higher frequency (which is limited by the op amp frequency response).
Try reducing the value of R5 (to around 5kΩ or so) to increase the frequency and see if that has any effect.

 

So I'm going to test that with the resistor, but I have been getting better results by switching out the inductor for a transformer primary but I'm going to try changing R5 now and try the smaller inductors, but the primary right now gives a sinesoidal wave that is stable almost all the way

 

Well I have pushed my PWM generator to 9KHz and the signal is wonky AF but it drives my FETs. I have also decreased my output capacitance to 500nF and I'm still using the transformer as L1, I have been able to reduce my "minimum voltage" to 10V I have to go to bed now but I'm going to try reducing the output cap further tomorrow . Do you think it's going to help? Or should I go for different op amp, go to 100Khz or more and try agian also with better Mosfets(lower Rdson)? If so what characteristics should the op amps have?

Also thank your help so far improving/almost fixing my circuit good man

 

I have to go to bed now but I'm going to try reducing the output cap further tomorrow . Do you think it's going to help?

I doubt it but it doesn't hurt to try.

Or should I go for different op amp, go to 100Khz or more and try agian also with better Mosfets(lower Rdson)? If so what characteristics should the op amps have?

I don't think a lower Rds(on) will help unless the Rds(on) is quite high.
More important, you want a low gate charge specitication, which makes the MOSFET hard to rapidly switch.

You want op amps with a high gain-bandwidth-product (GBWP).

If you want to go to a faster PWM you might consider the alternate circuit I posted.
Here's a writeup on it.

 

So I have ran a couple test simulations and searched for a comparable part(LT1001) for my current real opamps(lm358p) and I found out, that my ciruit will work on higher frequencies with better opamps and also that your circuit with my opamps won't produce a higher frequency reliably than my current circuit is producing anyway, I will order new opamps and try it out with 200KHz or there about and tell you the resulsts then. Thank you anyway for that writeup as I will keep that circuit in mind (and on hard drive ) for the future

 

Hi for a last time in this post, because I'm going to mark it as solved now. The voltage can be controlled from ca. 2V to 34V with a potentiometer. The simulation helped me to adjust all the values and choose my components. Thank you a thousand times for your great help

As a summary I learned, that the problem was the "incompability" of my frequency and my output stage, especially the inductor. Right now I am working on the feedback system and other features, but I can tackle those on my own. Also I am now using proper comparators and the f goes up to about 200kHz somewhat nicely

Cheers!