The Key Technology Research Of The Digital Intermediate Frequency Induction Heating Power Supply

Medium frequency induction heating power have in a wide range of applicationsin industry because of the advantages of the small size, high efficiency, energy savingconvenient and the small pollution. At present domestic medium frequency inductionheating power key circuit is mainly parallel inverter circuits, the control system mainlybased on integrated digital control system.This subject taking the half bridge series resonant inverter circuits as the maincircuit, use the TMS320F2812DSP as the main control chip, carry on the research onthe main circuit and control system on the digital intermediate frequency inverterpower:(1) When the current which flows through the series resonant inverter circuitsswitch components reduced to zero, switch components can be natural shut off, savethe switch components shut off circuit. According to this characteristic, design a peakdetection circuit that is the auxiliary circuit of the zero detection circuit in order to testthe intermediate frequency output current of the inverter circuits, judge the natural shutbreakpoint of switch tube, prevent the phenomenon of switch tube connecting directly,solve the problem of the switch components in inverter circuits need to take a reversevoltage shut off. make sure that the switch tubes work in the natural state of reversing.(2) On the intermediate frequency power digital control, the domestic is mainlyadopt the integrated digital control system, there are to be further research in intelligentcontrol. Load equivalent parameters and the inherent frequency may change while thework piece heated to a certain temperature during the heating process, and this willreduce the efficiency of power supply, so the traditional load frequency tracking method was improved, use the frequency lock-phase lock loop to track the load circuitfrequency, control the pulse sending triggered by switch tube, make the switch tubework on the nearly inherent frequency, improve the power work efficiency, reducepower consumption.Modeling and simulation for the control system through the Multisim andSimulink software, verify the superiority and feasibility of this study.