The Study Of Technique Of PLL-controlled In High Frequency Induction Heating Power Supply

In this paper the technique of PLL-controlled in high frequency induction heating power supply is studied. The author establishes the models of fixed-angle-control and fixed-time-control of MOSFET series resonant inverter. The advantages and disadvantages of these two methods are analyzed, and we get the conclusion that the fixed-angle-control method is the better one. The author explores the selection of the best angle through theoretical analysis and measuring the losses of MOSFET. The fixed-angle-control circuit which controlled by DSP is designed,and the modelling of simulation is established. Finally, the author verifies the feasibility of this method through simulation and generates the DSP codes. This method can guarantee the inverter operate in the small-inductive-quasi-resonant condition, reduce the switching losses of MOSFET, and it has some advantages including simple ciucuit, fast response and flexible controlling, so it establishes the good base of application of engineering.