Induction heater circuit problem
I have been afflicted with this circuit several times before .Its on the internet so it must be good?! .If L2 is saturated the loop gain of the osc is very low and it can stall .If input current is not limited then T1 and /or T2 will blow.Make sure that L2 can hack the prospective currents .Use a linear variable Psu for runup to avoid blowing fets .C1 must be high Quality because the circulating high frequency currents could be many times the Dc supply current .Use lots of lower value film caps in paralell for C1.If you use a seperate transformer with a ferrite core with a seperate gate winding for your feedback you will be better off .It is better to start your osc in a controlled class A situation .The ZVS royer is commonly used with BJTs but to make it reliable with mosfets requires a little more nouse .If you can get it to go on your lab supply then you can do a buck convertor with current limit and soft start for a reliable product.Under steady state conditions the peak drain volts is PI times the supply volts But with a hard start you can get twice this so check your ratings .Remember that the mosfets  must     have gain to start .If the biasing turns one hard on and one off you will stall.