Research On HF MOSFET Drive Circuit And Parallel Characteristics

At present, the crystal growth equipment is equipped with vacuum tube HF(lMHz-2.5MHz) induction heating power supply. While this supply has many disadvantages, such as low reliability, short longevity of vacuum tube, operational safety, low transfer efficiency. Existing huge capacity solid induction heating power supply cannot meet this need. So it is urgent to design and produce this HF induction heating power supply. This task is based on MOSFET multidevices parallel inverter on HF(lMHz-2.5 MHz). It's very necessary to design the drive circuit and discuss problems that maybe occur on HF. This provides some experience for the designing and debugging of electrical source, reduce the cost and advancing efficiency.This thesis pays more attention to the HF MOSFET drive circuit and characteristics of balancing parallel MOSFETs' currents in dynamic mode. At first the principle and characteristics in static and dynamic mode of power MOSFET are introduced. Grounding on the characteristics, the parameters of drive circuit are calculated and an applied and reliable drive circuit is proposed. Next, parallel MOSFETs maybe make currentsof MOSFETs unbalanced because of the unequal parameters of components on HF, which is simulated and analysed. At last, research on the characteristics of two parallel power MOSFETs on megahertz in dynamic mode are experimented and some available measures are made to balance the currents.Experimental results show the measures are very effective and good effect is got.