Research On Frequency-Tracing Control Circuit For High Frequency Induction Heating Power Supply

At present, the crystal growth equipment is equipped with vacuum tube high frequency (lMHz-3MHz) induction heating power supply imported from overseas or produced in China. While this kind of power supply has many disadvantages, such as low reliability, short longevity of vacuum tube, operational safety and low transfer efficiency, existing huge capacity solid induction heating power supply cannot replace them to meet industrial needs. So it is urgent to design and produce a high frequency induction heating power supply. It' s very necessary to design and utilize the drive circuit of high frequency power MOSFET, power regulation circuit and frequency-tracing circuit as three very important parts in control system of induction heating power supply. All those provide some experience for the designing and debugging of electrical source, reducing the cost and advancing efficiency.This thesis pays more attention to the drive circuit of high frequency power MOSFET, power regulation circuit and frequency-tracing circuit.Firstly, the driving characteristics of high frequency power MOSFET and parameter computation of drive circuit are introduced briefly. Then the useful and reliable drive circuit is designed. Secondly, the power regulation circuit is discussed in detail, and the high frequency phase-shift power regulation circuit is studied detailedly. Lastly, the frequency-tracing circuit is designed with phase-locked-loop. After that, the protect circuit and current voltage regulation circuit are also designed.Experimental results show the measures are very effective and good effect is got.