DIY 6kw induction heater with delayed lock loop(DLL)and pulse density modulation control

this is another series resonant induction heater ,current limiting and power control is done with pulse density modulation algorithms, for tracking the resonant frequency, for the first time it use a delayed lock loop(DLL) instead of commonly used PLL ,the main advantage of using DLL is its very short locking time that increases the reliability of the switching devices ,as shown in this video the heater can withstand and track very fast changes on the resonant circuit,like shorting the work coil and beacuse of using pulse density modulation , there's no hard switching at any point and we can choose low rated components: IGBTs:4X fgh40n60smd on full bridge toplogy maximum output: 6KW single phase frequency range:30-100khz maximum output current:800A can withstand short circuit of work coil and noneloade situation continuesly