The Design Of The High-frequency Induction Heating Power Supply

The main research object of this thesis is the high frequency induction heatingpower supply. First of all introduce the background knowledge and the basic principleof induction heating technology and expound the development situation, future trendsand advantages. After analysis and comparison of the two resonant circuit and theirinverter topology structure, according to the requirements, select the series resonantinverter. Analyzing the three kinds of working states of the series resonant inverter,choose the weak sensibility for the best practical working state.Then present the whole machine design of induction heating power supply andfigure out the parameters of bridge rectifiers, filter capacitor, power line filter, powerswitching device and resonant circuit in the main circuit and design the load matchingtransformer, current transformer and auxiliary power supply. The load parameterchanges effect on the resonance frequency in the process of heating, in order toeliminate the influence, design a frequency tracking circuit based on CC4098, thecircuit adopting the analog control circuit with SG3525PWM integrated circuit, cancarry out the frequency automatic tracking easily. Design the power control circuit tocontrol the load power. Design the driving circuit which can not only control thepower switching device on and off, but also insulate the main circuit and the controlcircuit. Also design the protection circuit, to ensure the normal operation of power.Finally present the experimental waveforms of each function module. Theresults show that the frequency tracking circuit has stable frequency trackingperformance and can achieve the ideal effect when the inverter works in weakemotional state. Therefore this design reaches the expected requirement.