The Application Research Of The DPLL In Special-shaped Plate Preheating Power Supply

The application background of this subject is the preheating treatment of the profiled sheetmetal before welding.It needs to preheat the special-shaped plate before welding in order toensure the welding quality.Preheating device uses electronmagnetic induction heating powersupply.So this paper study the heating power supply as a object.When the special-shaped plate is preheated,due to the different degrees of groove,Temperature and environmental change,it cause the changes of the preheating power loadinductance,therefore preheating device has wide frequency tracking range,and to be fast andreliable,if the frequenrcy tracking is not timely produced,the preheating power supply will bedamaged.Based on the demand above,in order to realize the wide range frequency tracking ofpreheating power supply and to overcome the traditional shortcomings of PLL,the paper is nolonger uses the PLL control system based on CD4046,but uses the DPLL based on DSP tocontrol.that is to use the PI controller and the DPLL controller in combination,even when theload has large disturbance,the system can quickly and reliably realize the frequency wide rangetracking.In this paper the control system is introduced and designed.At the same time this paperelabrates the working principle of the electromagnetic induction heating device,in the light of thepaper’s study requirements it selects the series resonant inverter and PWM power modulationafter topology analysis.Based on the foundation of the theretical analysis,this paper select TMS320F2812as themain control chip,it studies the induction heating power supply with75kw/20kHz as a object anddo experiments to verify the feasibility and correctness of the theory.