Research On Increase Of High-Frequency Inverter's Capacity For Induction Heating

Induction heating power supply is equipment for heating the work piece, utilizing the electromagnetic induction principle. Selecting its working frequency and designing induction coils can control the density of power distributing inside the work piece. The emergence of fast-switching power semiconductor devices, which are applied widely in industry today, have made it possible to implement high-frequency inverters for induction heating. In studying and developing high-frequency inverter, it is expected to solve the problems of increasing capacities of power output. This paper regards power MOSFETs as the main switching device to improve capacity of high_frequency (1MHz-2.5MHZ) induction heating power in order to fulfill the requirement that the monocrystalline silicon craft produces.At first, series resonant inverter is selected by comparing several kinds of common topological structure of inverter circuit; load parameters of the component are calculated to improve Q; then the principle and characteristics in static and dynamic mode of power MOSFET are introduced. Grounding on the characteristics, the method is given to compute power dissipation in detail, the parameters of drive and subber circuit are calculated. Next, by working over the characteristics of dual, trinary and even multitudinous parallel operation of power MOSFETs to improve the capacity of output, studying theimpact of the inductance of the lead wire, giving the methods to compute the inductance, analyzing and simulating the dynamic and static state, the paper discussed some available measures to balance the current; At last, the paper indicates some tracing waves on the integral circuit, which can be made up of inverter circuit, PLL and subber circuit etc. The results could provide some experience for the designing and debugging of electrical source.