Research On The Design Optimization Of Induction Heating Coil And The Control Of Variable Frequency Power Sources

With the development of the induction heating technology,more domestic productions have replaced the import ones in a sharp increase rate,especially in the steel and relevant industries.The primary components include induction heating coil、the AC power and artifacts.Since heated objects are different,the coil could be made to different shapes.Connecting the power to coil,the coil can get the electricity,which generates a alternating magnetic field for producing the AC power to heating through the coil,from the power.Thus,the induction heating coil is one of the key factors to control the quality of heat treatment and improve the efficiency of the induction heating equipment.This dissertation introduces the design principle and improvement method of the induction heating coil,and the magnetic field control theory and implementation of eddy current effect and magnetic shielding.Based on the project of structural optimization design of IF electric induction heating coils of Special Steel Business Division of Baoshan Iron&Steel Co.Ltd,this dissertation focuses on problems of induction heating coil during the implementation and design drawbacks,we provide some design and improvement approaches for the coil of the waterways,and magnetic shielding,and heat-resistant,insulation and the water flow,temperature monitoring to solve the high frequency problems of the electric arc phenomenon,leaking and overheating to improve the reliability of the coil.The main contribute of this dissertation can be concluded as follows.1.According to the theory of IF induction heating technology and design parameters of induction heating coil,this dissertation focuses on the problems of the electric arc phenomenon,leaking and overheating,and improves the cooling system,enhances the insulation of induction heating coil,adds the thermal protection layer by using thermal radiation protection technology,adds the temperature sensor of cooling water for the connector and install the flows switch at the backwater of the coil.Thus,the above problems can be fixed completely and practice implementation can be guaranteed.2.Analyzing the theory of induction heating.Based on the studies the control methods of the system of induction heating,this dissertation improve the ability of loading and heating of the coil.It not only solves the problems of the electric arc phenomenon,leaking and overheating,but also improves the efficiency of the coil.The results shows the proposed methods meet the requirements in the practice.3.Analyzing the development trends of induction heating techniques.The dissertation analyzes the relationship between eddy current effect and AC frequency,and gives the relationship between induction healing and resonance.It also studies the control of variable frequency power sources.With the fact that performance of the large capacity and high frequency of the power device has been improved,the hardware level of induction heating coil will be raised along with its performance which also could be concerned in the future study and development.