Series Resonant Type For Industrial Quenching Research And Design Of High Frequency Induction Heating System

Against the backdrop of a shortage of modern energy and the need for clean development in the 14 th Five-Year Plan period,modern industrial heating processes prioritize the use of induction heating over traditional coal heating methods.This thesis focuses on the surface hardening and local heat treatment of high-strength shaft parts in industrial production.It studies and designs a high-frequency and wide-tuning range induction heating system based on series resonant circuits,which provides high-frequency AC power through a single-phase full-bridge inverter unit.A DC/DC power matching circuit is added before the single-phase inverter circuit to control the output voltage,current,and power by pulse width modulation strategy,indirectly controlling the heating power of the induction heating coil and ultimately achieving temperature control of the workpiece.The main work of this thesis includes the following:First,this thesis proposes the use of a DC/DC power matching unit in combination with a single-phase voltage-type full-bridge inverter unit to provide high-frequency AC power to the induction heating unit,which is LC series resonant,to ensure the maximum power and highest efficiency of the system.The theoretical analysis and load characteristic calculation of the system’s operating state are carried out based on the switch mode.A power control strategy is designed for the front-end DC/DC power matching unit.A double-closed-loop control strategy for the Buck chopper circuit’s voltage outer loop and current inner loop is modeled based on the state space averaging method.The compensation network is designed using the MATLAB/SISOTOOL toolbox.The PI integral separation algorithm is used to improve the system’s dynamic response performance.A simulation model of the system’s circuit topology is built in PSIM to conduct open-loop parameter scanning and closed-loop control simulation,and to analyze the open-loop scanning characteristics of the circuit system and the stability of the designed closed-loop control system.Next,to address the surface hardening heat treatment problem of shaft parts,this thesis builds a finite element simulation model of the system in COMSOL according to actual application scenarios.The heating process temperature system is simulated by coupling the magnetic field with the temperature using finite element method.Temperature field parameter scanning and magnetic field response characteristic analysis are carried out to study the influence of power-related parameters on the induction heating effect.Finally,with ds PIC33FJ64GS606 digital controller as the core,this thesis builds a hardware experimental platform for the system,designs the main circuit,drive circuit,voltage/current sampling circuit,and DSP software processing flow for the system’s three operating modes,and conducts open-loop and closed-loop experiments on this platform to verify the correctness of the system and the effectiveness of the control system.