Simulation Research Of High Frequency Induction Heating Power Supply Based On DSP

Induction heating technology is a heat treatment technology which uses alternatingmagnetic field to generate eddy currents heating the metal devices. Induction heating powersupply works as a major energy conversion device in the power induction heating equipment,its output power increases with the needs of production, its frequency regulation is more andmore intelligent. On the one hand, induction heating power supply requires the loss of powerdevices as small as possible, on the other hand it requires its power regulation and frequencyregulation have the ability to quickly adjust. In this paper, respectively, a lot of research wasdone for both frequency tracking technology and power regulation technology.The inverter frequency of high frequency induction heating power supply should trackthe load natural resonant frequency directly. Firstly the equivalent circuit of the power supplyload was analyzed and the load natural resonant frequency of different resonant circuits wascalculated. Secondly inverter operations of the induction heating power supply at capacitive,inductive and resistive conditions were analyzed based on voltage-type series resonant circuitand small inductive quasi-resonant condition is the achieved ideal working condition in thepower supply. In order to working at small inductive quasi-resonant condition, the inverteroperation frequency should track the load natural resonant frequency timely. In theengineering, phase-locked loop was used to solve the tracking problems. Timing phase lockedmodel and fixed angle phase locked model with MATLAB/simulink software were builded tocompare. Finally fixed angle phase locked model was adopted to solve the frequency trackingproblem.Traditional analog phase-locked loop has shortcomings such as poor trackingperformance, small lock range, low circuit accuracy, and the inverter can not achievereal-time dead time adjustment. Digital processing chip not only has high processing speedand high data accuracy, but also internally integrates multiple PWM waveform generationmodule and simultaneously generates multiple PWM signals. This paper used digital signalprocessing chip to build a digital phase locked loop model with PI regulator (PI-DPLL), themodel can track faster load resonant frequency and inverters achieve online dead zoneadjustment. Meanwhile the paper studied the buck chopper dual closed loop poweradjustment to achieve a rapid adjustment of electrical power.