The Research Of Super-Sonic Parallel Resonant Solid Induction Heating Power Supply

This paper has researched 20kHz super-sonic solid induction heating power supply. Firstly, it has introduced the history and basic knowledge of induction heating and the development of power electronic devices are also introduced. Furthermore it introduces the aim of the paper. Control strategy is designed in this paper. The load character and control object for a parallel inverter is analyzed, the conclusion that series and parallel resonant circuit are two antithetic circuits is used to provide a theoretical guide to the control circuit design for the inverter. Through the analysis of different operating states, it is pointed out that a capacitive quasi-resonant state is a safe and efficient working condition for a parallel inverter. A starting method is brought forward which switch the starting from separate exciting to self-exciting successfully; PLL(Phase Lock Loop) technology is employed to realize the frequency tracing; On the basis of Pspice simulation, we gave the detailed frequency closed-loop-control circuits. The Buck converter centering on PWM controller SG3525 is made up of IGBT to level off the output voltage of inverter. At last founded on the experiments of element circuit, we carried on the complete machine experiment which proved that the design is feasible.